Unit 1 (all cards) Flashcards
1
Q
Define anatomy
A
Examining the structure of the human body
2
Q
Define physiology
A
The study of function of the human body
3
Q
True or false: Anatomy and physiology complement each other; you can not entirely separate the two because of the unity of form and function
A
True
4
Q
Define gross anatomy
A
Study of structures that can be seen with the eyes
5
Q
What are three examples of gross anatomy being applied in medicine?
A
Dissection, exploratory surgery, and medical imaging
6
Q
Name 3 areas that study anatomical structures too small to be seen with the naked eye
A
Histology, cytology, and ultrastructure
7
Q
What is another name for histology?
A
Microscopic anatomy
8
Q
What is histology?
A
The examination of tissues [under a microscope]
9
Q
What is cytology?
A
The study of structure and function of cells
10
Q
What is ultrastructure?
A
Viewing detail under an electron microscope
11
Q
Name 3 subdisciplines of physiology
A
Neurophysiology (physiology of the nervous system)
Endocrinology (physiology of hormones)
Pathophysiology (mechanisms of disease)
12
Q
Define pathophysiology
A
The study of mechanisms of disease
13
Q
Define comparative physiology
A
The study of another species to learn about body functions
14
Q
What is the basis for much of our understanding of human physiology and the development of new drugs and medical procedures?
A
Comparative physiology
15
Q
Why is comparative physiology important to research in physiology as a whole?
A
Physiology, unlike anatomy, requires live subjects due to the fact that you cannot observe function on a cadaver, so often relies on animals to perform research
16
Q
Define organization in anatomy
A
The idea that living things exhibit a higher level of organization than nonliving things.
17
Q
Living matter is always compartmentalized into ____ or more cells.
A
one
18
Q
What is cellular composition?
A
The idea that living matter is always compartmentalized into one or more cells.
19
Q
What is metabolism?
A
Internal chemical reactions
20
Q
True or false: all chemical reactions that take place inside your body are considered to be a part of your metabolism
A
True
21
Q
Define responsiveness in biology
A
The ability to sense and react to stimulate (irritability or excitability).
22
Q
Define movement in biology
A
The movement of organisms and/or of substances within the organism.
23
Q
Define homeostasis
A
Maintaining relatively stable internal conditions (regardless of external conditions)
24
Q
What is the one word that can sum up many of the topics covered in A&P one and two?
A
Homeostasis
25
Define development in biology
Differentiation and growth
26
Differentiation and growth make up the concept of ________.
development.
27
Give an example of why monitoring development is important to medicine
Looking a developing fetus in the womb to see if structures are differentiating and growing at the typical rates.
28
Define reproduction
Producing copies of themselves; passing genes to offspring.
29
Define evolution in biology
Changes in genes at the population level
30
Give an example of evolution that is relevant to modern medicine
Bacteria evolving to resist antibiotics on a population level.
31
What is the general idea of the body’s structural hierarchy of complexity?
Atoms are the least complex component of life, organisms are the most complex.
32
Define elements
The simplest form of matter with unique properties.
33
All elements are made up of what three things?
Electrons, protons, and neutrons
34
What are the three main elements covered in this course?
carbon, oxygen, and nitrogen
35
Define atomic number
The number of protons in an element; this gives the element its identity
36
Define protons
A positively charged particle within atoms, the number of which give the atom its elemental identity
37
What two things are located in the nucleus of an atom?
Protons and neutrons
38
Where are electrons located?
Around the nucleus
39
What is atomic mass?
Number of protons + number of neutrons = atomic mass
40
Define an isotope
Atoms with a missing or extra neutron
41
Define a neutron
A neutral particle in the nucleus of an atom that gives the element its atomic mass
42
Define an electron
A small negatively charged particle that orbits the nucleus of an atom
43
The first energy shell is full with _ electrons, the second shell is full/ stable with _ electrons, and the third shell is full/stable with _ electrons.
The first energy shell is full with 2 electrons, the second shell is full/ stable with 8 electrons, and the third shell is full/stable with 8 electrons.
44
Ionization occurs because _____
atoms want their shells to be stable and full of electrons.
45
Define an ion
A substance that has a charge from gaining or losing electrons
46
Define cation and anion
Cation: positively charged ion
Anion: negatively charged ion
47
Define ionic bond
A charge attraction between a cation and anion.
48
Define valence electrons
Electrons in the outermost shell
49
What is a covalent bond and how is it represented?
A bond through shared valence (outer) electrons. Usually represented by a dash or subscript (i.e. H-H or H₂)
50
Like a ____, water molecules have charged regions
battery
51
What kind of bond is found in water molecules?
Polar covalent bonds
52
Define polar versus nonpolar
```
Polar = evenly shared electrons
Nonpolar = unevenly shared electrons
```
53
What are polar covalent bonds?
Electrons are shared unequally within a covalent bond.
54
Give an example of an nonpolar molecule
O^2
55
Which of the following repel each other and don't mix?
a) polar and polar bonds
b) polar and nonpolar bonds
c) nonpolar and nonpolar bonds
b) polar and nonpolar bonds
56
Why don't oil and water mix?
Because nonpolar and polar bonds hate each other; lipids found in oil are mostly made of nonpolar covalent bonds, and water has polar covalent bonds.
57
Define hydrogen bonds
The weakest type of bond formed because of attraction between a slightly positive hydrogen and a slightly negative oxygen (or nitrogen).
58
What is the weakest type of bond?
Hydrogen bonds
59
When you put two molecules of water together, they form a hydrogen bond. Why?
The polar covalent bonds allow for the hydrogen bonds between water molecules.
60
Define cohesion and adhesion
Cohesion: Water is attracted to water
Adhesion: Water is attracted to other substances.
61
What mixes in water?
Substances similar to water (meaning polar, charged ions).
62
Define a solution in chemistry
A mixture of dissolved substances called solutes, and dissolving agents called solvents.
63
What is the most common solvent used in this class? Why?
Water, because our bodies are mostly water
64
Define a mixture
A combination of two or more elements without a chemical reaction
65
What are the four types of organic molecules?
Proteins, lipids, carbohydrates, and nucleic acids
66
What are the monomers and polymers of proteins?
```
Monomers = amino acids
Polymers = polypeptides
```
67
Where did polypeptides get their name?
The bond between amino acids is called a peptide bond
68
What are the monomers and polymers of carbohydrates?
```
Monomers = monosaccharides
Polymers = Polysaccharides, starch, glycogen, cellulose
```
69
What are the monomers and polymers of lipids?
```
Monomers = for triglycerides: glycerol, 3 fatty acids
Polymers = phospholipids
```
70
What are the monomers and polymers of nucleic acids?
```
Monomers = Nucleotides
Polymers = DNA, RNA, ATP
```
71
Proteins: There are ____ amino acids
20
72
Proteins: Side chains (also called the R group) can be _____ or _____.
Polar or nonpolar
73
Proteins: What do side chains/ the R group determine?
They can be polar or nonpolar, which determines how amino acids interact with each other.
74
Proteins: The sequences of amino acids determine what?
How the protein folds, which determines the protein’s function.
75
What are the four structures of proteins?
Primary structure = amino acid sequence
Secondary structure = hydrogen bonding between amino acids
Tertiary structure = interactions of side chains
This is what makes each protein really unique.
Quaternary structure = two or more polypeptides
76
In proteins, shape determines ______.
function
77
The hydrogen of one water molecule is attracted to what part of the other water molecule?
The negative part
78
What does it mean when we say that water is polar?
It means that water shares its electrons unequally between the oxygen atom and the hydrogen atom, which creates charge regions, which creates a partial charge.
79
The attraction between parts of two different polar molecules is called ______ bonding.
hydrogen
80
True or false: Hydrogen bonding usually takes place between two of the same molecule.
False; hydrogen bonding usually takes place between two different molecules (usually a molecule with hydrogen + one with oxygen or a molecule with hydrogen + one with nitrogen)
81
The tendency for molecules of water to cling to one another, is that an example of adhesion or cohesion?
Cohesion
82
Give an example of why cohesion (water sticking to water) is important to the human body
The water on the surfaces of our lungs clings to the water on the surface of our inner chest muscles, which is what allows our lungs to inflate when our chests rise (if the cohesion is lost, lungs can collapse).
83
Why does water bead up on some substances and soak into others?
Because some substances, like wax paper (which consists of lipids), have primarily non-polar bonds, which repel oxygen’s polar covalent bonds.
84
Why do we use cotton towels to dry ourselves when we get out of the shower?
Because cotton has a polar charge, which allows it to bind to water and dry you
85
Non-polar bonds of a substance (like oil or soap) repelling the polar bonds of water can lead to what?
Decreased surface tension
86
Why can insects walk on water?
Surface tension
87
Will nonpolar and polar molecules interact?
No
88
What happens when you bring two chloride ions together?
They repel each other because they are both negatively charged
89
Which of the following would have a higher level of salt: A solution of 15% NaCI or a solution of 30% NaCI?
30% NaCI
90
Which of the following would have a higher level of water: A solution of 15% NaCI or a solution of 30% NaCI?
15% NaCI
91
In a solution of 15% NaCI, is water the solute or solvent? What about the NaCI?
Water is the solvent and NaCl is the solute
92
What four types of molecules mix with water?
Polar molecules, hydrophilic molecules, molecules with ionic bonds, and proteins (most contain polar covalent bonds; some are anions)
93
What two types of molecules don't mix with water?
Nonpolar and hydrophobic molecules
94
In the human body, nutrients, including vitamins, are transported to the cells by the blood. Vitamins can be divided into two types– water-soluble vitamins and fat-soluble vitamins. Since blood is mostly water, the water-soluble vitamins are easily transported to their destinations. How do you think the fat-soluble vitamins travel in the blood?
Proteins pick them up and carry them.
95
Define elements
The simplest form of matter to have unique chemical properties cannot be broken down by ordinary chemical means
96
How many naturally occurring elements are there?
91
97
Define atoms
The building blocks for each element
98
How many elements have a biological role?
24
99
What 6 elements make up 98.5% of our body weight?
```
Oxygen (O)
Carbon (C)
Hydrogen (H)
Nitrogen (N)
Calcium (Ca)
Phosphorus (P
```
100
Lesser elements make up what percent of the body?
0.8%
101
Trace elements make up what percent of the body?
Less than 0.7%
102
Where and in what quantity are trace elements found in the body?
They're required in minute amounts and are found as a part of enzymes
103
Give examples of lesser and trace elements
Lesser: K, S, Na, Cl, Fe, Mg
Trace: I, Co, Cu, Z, Cr, etc.
104
Define minerals
Inorganic elements extracted from soil by plants and passed to humans
105
What percent of our body weight is made up of minerals?
4%
106
What two minerals are most commonly found in the body? What are some other minerals in the body?
Mostly Ca and P (also Cl, Mg, K, Na, and S)
107
Define electrolytes in the context of minerals
Mineral salts needed for nerve and muscle function
108
What are the three components of atoms?
Protons, neutrons, and electrons
**This is just a note to myself that this chapter does also cover the basics of protons, neutrons, and electrons, but those flashcards can be found in lab 2**
109
Elements with an abnormal number of neutrons are called ____
Isotopes
110
Average of mass numbers of an element = ______
Atomic weight
111
True or false: most isotopes are stable. Why?
True; few will disintegrate and give off energy
112
Intense radiation can be ionizing, how does this affect the body?
Intense radiation can be ionizing (ejects electrons, destroys molecules) and can cause genetic mutations and cancer
113
Where are radioactive isotopes used in medicine? What are some other examples?
Used for radiation therapy and diagnostic procedures. This includes PET scans, using I-131 determine size and activity of the thyroid gland, Hida scans (Tc-99 technetium with a ½ life of 6 hours), Cobalt-60 for cancer
Other examples of radioactive isotopes include UV radiation, X-rays, alpha particles, beta particles, gamma rays
114
True or false: All elements have at least one radioisotope
True
115
True or false: X-rays and CT scans use radioactivity
False; they use very short electromagnetic waves.
116
Electron shells are also called ________
energy levels
117
In neutral atoms, number of electrons equals number of protons. Non-neutral atoms have a different number of electrons than normal; what are they called?
Ions (or electrolyte)
118
Define cations and anions
Anion—particle that gains electron(s) (net negative charge)
| Cation—particle that loses electron(s) (net positive charge)
119
Ions with _____ charges are attracted to each other
a) opposite
b) same
a) opposite
120
Define electrolytes
Substances that ionize in water (acids, bases or salts)
121
Define salts
A compound (ex: NaCl) that can dissociate into water and contains cations (Na) and anions (Cl)
122
Define a molecule
Chemical particle composed of two or more atoms united by a chemical bond
123
Define a compound
Molecule composed of two or more different elements
124
Define molecular formula
Identifies constituent elements and how many atoms of each are present
125
Define structural formula
Identifies the location of each atom
126
What do chemical bonds do?
They hold atoms together within a molecule or attract one molecule to another
127
What are the three most important types of chemical bonds?
Ionic bonds, covalent bonds, and hydrogen bonds
128
Inert elements have a ____ outer shell
a) incomplete
b) full
b) full
129
Reactive elements have a ____ outer shell
a) incomplete
b) full
a) incomplete
130
Define ionic and covalent bonds
Ionic bonds: will transfer (gain/lose) electrons
| Covalent bonds: will share electrons
131
Describe ionic bonds in detail (the attractions are between ____ and ____; electrons are shared or transferred; how easily are they broken)
Attractions between anions and cations
Electrons donated from one atom to another
Easily broken by water
132
____ compounds form crystals instead of individual molecules
Ionic
133
Define a single covalent bond
One pair of electrons is shared
134
What is the strongest type of bond?
Nonpolar bonds
135
In what type of bonds do electrons spend more time near oxygen?
Polar bonds
136
Define polar and nonpolar bonds
Nonpolar bond: electrons shared equally (strongest bond)
| Polar bond: electrons shared unequally (spend more time near oxygen)
137
_____ sharing of electrons produces polar molecules
Unequal
138
What is an example of an intermolecular hydrogen bond? An intramolecular hydrogen bond?
Intermolecular hydrogen bond between water molecules
| Intramolecular hydrogen bonds helps protein folding; holds sides of DNA together
139
Define hydrogen bonds
Weak charge attraction between a slightly positive hydrogen and a slightly negative oxygen (or nitrogen)
140
Define mixtures
When elements/molecules/objects are physically blended but not chemically combined
141
What are body fluids?
Complex mixtures of chemicals
142
What percent of the body is made up of water? What factors determine this?
Water is 50% to 75% of body weight; this depends on age, sex, fat content, etc.
143
What two things give water the properties to support life? What are these properties?
Polar covalent bonds and a V-shaped molecule give water solvency, cohesion, adhesion, chemical reactivity, and thermal stability
144
Define solvency
The ability to dissolve other chemicals
145
Define hydrophilic and hydrophobic
Substances that dissolve (mix) with water are Hydrophilic
| Substances that do not mix easily with water are Hydrophobic
146
What is the universal solvent?
Water
147
Metabolic reactions depend on ______ of water
solvency
148
Define adhesion versus cohesion
Adhesion—water adheres to other substances
| Cohesion—water molecules cling to each other
149
Give an example of adhesion in the body
Water adheres to large membranes reducing friction around organs
150
Water adhering to large membranes is an example of _____
adhesion
151
Why is water so cohesive?
Its hydrogen bonds
152
What is surface film (think bugs walking on water) on the surface of water due to?
Surface film on surface of water is due to molecules being held together by surface tension
153
Which element's thermal stability helps stabilize the internal temperature of the body?
Water's
154
Define high heat capacity and explain why water's heat capacity is so high
Something with a high heat capacity absorbs and releases large amounts of heat before changing temperature.
In water, hydrogen bonds inhibit temperature increases by inhibiting molecular motion.
155
What is an effective coolant?
Water
156
What is chemical reactivity?
The ability to participate in chemical reactions
157
Water ionizes into what two things?
H^+ and OH^−
158
What can water ionize?
Water ionizes many other chemicals (acids and salts)
159
Define acids
A substance that dissociates in solution to produce hydrogen ions (H+) and anions.
160
Define bases (also called alkalines)
A substance that dissociates in solution to yield cations and hydroxide ions (OH-).
161
Name two important bases (aka alkalines) in the body
Bicarbonate ion (HCO3–) and ammonia (NH3) are important bases in the body
162
Define salt
A substance that dissociates in solution producing cations and anions but not hydrogen ions or hydroxide ions.
163
Define the three pH categories
Acidic: pH 0–6.99
Basic: pH 7.01–14
Neutral: pH 7.00
164
Body fluids each have their own ____ range they must maintain.
pH
165
What can help prevent large changes in pH?
Buffers
166
Define energy
The capacity to do work [move something]
167
True or false: all body activities are forms of work
True
168
Define potential energy and give an example
Energy stored in an object, but not currently doing work (ex: water behind a dam waiting to be released)
169
Define chemical energy and free energy
Chemical energy—potential energy in molecular bonds
| Free energy—potential energy available in a system to do useful work
170
Define kinetic energy and give an example
Energy of motion, doing work
| Example: water flowing through a dam, generating electricity
171
Define heat
Kinetic energy of molecular motion
172
Define a chemical reaction
A process in which a covalent or ionic bond is formed or broken
173
Define chemical equation
Symbolizes the course of a chemical reaction (reactants into products)
174
What are the two classes of chemical reactions?
Decomposition and synthesis reactions
175
What are decomposition reactions?
A large molecule breaks down into two or more smaller ones (i.e. AB > A + B)
176
What are synthesis reactions?
Two or more small molecules combine to form a larger one (i.e. A + B > AB)
177
Define reversible reactions. When do they reach equilibrium?
Reactions that can go in either direction under different circumstances. They reach equilibrium when ratio of products to reactants is stable.
178
When do reactions occur?
When molecules collide with enough force and correct orientation
179
When do reaction rates increase?
When:
the reactants are more concentrated
the temperature rises
a catalyst is present
180
Define metabolism
All chemical reactions of the body
181
Define catabolism
Energy-releasing decomposition reactions that break covalent bonds and produce smaller molecules
182
Define anabolism
Energy-storing synthesis reactions that require energy input and the production of protein or fat
183
Catabolism and anabolism are inseparably linked. Why?
Anabolism is driven by energy released by catabolism
184
Define organic chemistry
The study of compounds containing carbon
185
What are the four categories of carbon compounds/ organic molecules?
Carbohydrates, lipids, proteins, and nucleic acids
186
Define macromolecules
Very large organic molecules with high molecular weights
187
Define polymers and give an example
Macromolecules made of a repetitive series of identical or similar subunits (monomers).
Ex: starch is a polymer of about 3,000 glucose monomers.
188
Monomers are linked together by ____________ and polymers are broken apart by _____
Monomers are linked together by dehydration synthesis and polymers are broken apart by hydrolysis
189
Define dehydration synthesis
Monomers covalently bind together to form a polymer with the removal of a water molecule
190
Define hydrolysis
Splitting a polymer by the addition of water
191
What is the primary function of carbohydrates?
Energy
192
What is the general formula of carbohydrates? Give an example.
(CH2O)n, n = # of carbon atoms
| Ex: glucose, n = 6, so formula is C6H12O6
193
What are the three sizes of carbohydrate molecules
Monosaccharides, disaccharides, and polysaccharides
194
What are the three types of monosaccharides? How are they produced?
Glucose, galactose, and fructose. They're produced by digestion of complex carbohydrates
195
What is glucose known as in medicine?
Blood sugar
196
Define isomer
Same molecular formula – different arrangment
197
What are the three types of disaccharides?
Sucrose, lactose, and maltose
198
What is sucrose?
A disaccharide known as table sugar
| Glucose + fructose
199
What is lactose?
A disaccharide known as sugar in milk
| Glucose + galactose
200
What is maltose?
A disaccharide known as grain products
| Glucose + glucose
201
Give an example of a polysaccharide
Glycogen
202
What is glycogen and where is it found in the body?
A glucose polymer that is stored in the liver and skeletal muscles
203
Define starch
Energy storage in plants in the form of carbohydrates that is digestible by humans
204
Define cellulose
A structural molecule in plants that's a carbohydrate that is important for human dietary fiber (but indigestible to us)
205
Are carbohydrates hydrophilic or hydrophobic?
Simple carbohydrates are small polar molecules (containing several -OH groups) which makes them hydrophilic
206
Why are lipids only made up of one group?
Because either part of or the entire molecule is hydrophobic.
207
What makes lipids different from carbs and proteins?
Usually contains more nonpolar covalent bonds than carbs or proteins
208
True or false: lipids are a very diverse group
True
209
What is the difference between saturated and unsaturated fatty acids?
Saturated fatty acids have a lot of hydrogen
Unsaturated fatty acids contain some double bonds
Essential fatty acids must be obtained from food
210
What are triglycerides (neutral fats)?
Three fatty acids linked to glycerol
211
What is the primary function of triglycerides (neutral fats)? What other thing does it help with?
Their primary function is energy storage (2x more energy than carbs or proteins). They also help with insulation and padding (shock absorption (adipose tissue))
212
Since triglycerides are hydrophobic, how are they transported in the human body?
Proteins have to carry them (not sure about this one)
213
What are phospholipids?
They are similar to neutral fats except one fatty acid is replaced by a phosphate group
214
Phospholipids are made up of a ___ and ____
head and tail
215
What is the "parent" steroid from which the other steroids are synthesized?
Cholesterol
216
Give some examples of steroids
Cholesterol, cortisol, progesterone, estrogens, testosterone, and bile acids
217
What are steroids important for?
They're important for nervous system function and structural integrity of all cell membranes
218
15% of our cholesterol comes from our diet, where does the other 85% of cholesterol come from?
85% is internally synthesized (mostly in liver)
219
Define a protein
A polymer of amino acids
220
Define amino acids and what three things are attached to it.
They are a central carbon with three attachments:
| an amino group (NH2), carboxyl group (—COOH), and a radical group (R group)
221
What determines the properties of an amino acid?
The R group
222
How many amino acids are there?
20
223
Amino acids only differ from each other in what way?
The R groups differ
224
What is a peptide?
Any molecule composed of two or more amino acids joined by peptide bonds
225
How are peptides named?
```
According to the number of amino acids they have:
Dipeptides have 2
Tripeptides have 3
Polypeptides many
Proteins have more than 50
```
226
Peptides are a component of ____
Proteins
227
How do peptide bonds form?
Dehydration synthesis creates a peptide bond that joins the amino acid of one group to the carboxyl group of the next.
228
What does the confirmation of a protein mean?
The unique, three-dimensional shape of protein crucial to function
229
What is crucial to the function of a protein?
Its confirmation
230
True or false: Proteins can reversibly change conformation and thus function
True
231
Define denaturation and what causes it. Give an example.
Extreme conformational change that destroys the function of a protein caused by extreme heat or pH.
Example: when you cook an egg
232
What are three specific examples of body functions that require proteins?
Muscle contraction, enzyme catalysis, and membrane channel opening
233
What are the four levels of protein structure?
Primary, secondary, tertiary, and quaternary
234
What are the seven main functions of proteins?
Structure, communication, membrane support, catalysis, recognition & protection, movement, and cell adhesion
235
Give an example where proteins help with structure
In keratin and collagen.
(Keratin—tough structural protein of hair, nails, skin surface
Collagen—contained in deeper layers of skin, bones, cartilage, and teeth)
236
Give an example where proteins help with communication
Between some hormones and receptors
237
Give two examples where proteins help with membrane transport.
Channel proteins in cell membranes govern what passes. Carrier proteins transport solutes to other side of membrane.
238
Give an example where proteins are needed for catalysis
Most enzymes are globular proteins
239
Give an example where proteins help with recognition and protection
Antibodies are proteins
240
Give an example where proteins help with movement
Motor proteins are molecules with the ability to change shape repeatedly
241
Define motor proteins
Molecules with the ability to change shape repeatedly
242
Give examples where proteins help with cell adhesion
Proteins bind cells together (example: sperm to egg)
| and keep tissues from falling apart
243
What are enzymes and what do they do for our bodies?
They're proteins that function as biological catalysts by lowering activation energy. They permit reactions to occur rapidly at body temperature
244
What permits reactions to occur rapidly at body temp?
Enzymes
245
Define substrate
A substance an enzyme acts upon
246
How are enzymes named?
Named for substrate with -ase as the suffix
| Amylase enzyme digests starch (amylose)
247
What are the three steps of an enzymatic reaction?
1) Enzyme and substrate
2) Enzyme-substrate complex
3) Enzyme and reaction products
248
True or false: enzymes are reusable and not consumed by their reactions
True
249
Are enzymes fast or slow?
They work at an astonishing speed: One enzyme molecule can consume millions of substrate molecules per minute
250
What can change enzyme shape and function? What does changing an enzymes function do?
Temperature, pH and other factors can change enzyme shape and function, which can alter ability of enzyme to bind to substrate
251
Are proteins hydrophilic or hydrophobic?
Hydrophilic
252
Nucleic acids: Monomers are called _____
nucleotides
253
Nucleic acids: What are the four components of nucleotides?
1- Nitrogenous base
2- Adenine, Guanine, Cytosine, Thymine or Uracil
3- Sugar (ribose or deoxyribose)
4- One or more phosphate groups
254
Nucleotides become polymers called nucleic acids; what are three examples of nucleic acids?
ATP, RNA, and DNA
255
Nucleic acids: Describe DNA
Contains millions of nucleotides
Constitutes genes
Instructions for synthesizing proteins
256
Nucleic acids: Describe RNA's function
A nucleic acid that follows DNA instructions to assemble proteins
257
Nucleic acids: Describe ATPs function
ATP is body’s most important energy-transfer molecule
Holds energy in covalent bonds
Most energy transfers to and from ATP involve adding or removing the third phosphate
258
```
Which of the following are examples of compounds?
a) O2 and CO2
b) O2 and H2O
c) CO2 and H2O
d) all of the above
Bonus points: Why?
```
c) CO2 and H2O
Explanation: a compound contains two or more elements, and although O2 is a molecule, it is not a compound because it only has one element
259
True or false: a proton or electron of Carbon will act the same as a proton or electron of Oxygen.
True
260
Why do our bodies need iron?
Iron is needed for our blood; oxygen doesn’t go through blood on its own, so iron is needed to grab it and carry it around. This is why we have things like iron infused cereals.
261
Why do our bodies need iodine?
Iodine is used by the thyroid in thyroid hormones which are used for metabolism; you don’t need a lot, but if you don’t have it, you can’t make those hormones. This leads to low energy, cold feeling, etc. This is why we use iodized salt.
262
Give an example of why minerals are important to our bodies using potassium
High or low potassium (K) = cardiac arrest
263
What can radioactive isotopes do that stable isotopes can't?
They disintegrate and give off energy, and this energy can break chemical bonds
264
Give an example of using radioactive isotopes to negatively effect the human body
A former spy of soviet union was poisoned by someone putting a radioactive story in his tea (head this story before) and died due to radiation poisoning over a period of weeks.
265
Give an example of how radioactive isotopes are used in human medicine
We have ways to detect energy (like energy given off by radioactivity) and pick it up on a scan, so we can use these radioactive isotopes to see different parts of the brain (like plaques on the brains of Alzheimer’s pts)
266
True or false: atoms are not electrically neutral when they're not ions
False; they are electrically neutral
267
True or false: you always fill the inner electron shells first
True
268
Give an example of something that's a molecule but not a compound, and explain why
O2 is a molecule but not a compound, because compounds have two or more different elements.
269
Give an example of the importance of structural formula
Shape/location/structure can determine function (ex: glucose, fructose, and galactose all have the same formula, but different properties)
270
Give an example of inert elements with a full outer shell
Noble gasses
271
How are single covalent bonds usually represented?
Represented by a solid line
272
A weak charge attraction is also called a ____ ____
Hydrogen bond
273
Define intermolecular and intramolecular
Intermolecular: between individual molecules
Intramolecular: within an individual molecule
274
The intramolecular bonds in water are ____ _____ bonds, the intermolecular bonds between water molecules are _____ bonds
The intramolecular bonds in water are polar covalent bonds, the intermolecular bonds between water molecules are hydrogen bonds
275
The six most abundant elements in the human body are carbon, oxygen, hydrogen, phosphorus, calcium, and _____
nitrogen
276
_______ electrons are the electrons found in the outermost shell of the electron cloud.
Valence
277
Atoms of the same element that differ only in the number of neutrons are known as _____
isotopes
278
A cation has a net _____ charge.
positive
279
```
What is the term for an ion with a net negative charge (more electrons than protons)?
Cation
Isotope
Electron
Anion
```
Anion
280
Choose the six most abundant (by weight) elements that account for 98.5% of the body weight.
Carbon, oxygen, hydrogen, phosphorus, calcium, and nitrogen
281
What term refers to a covalent bond in which the electrons are not equally shared?
Polar
282
If an atom has 2 electrons in its innermost shell and 3 electrons in its outmost shell, how many valence electrons does it have?
3
283
Salt on a watermelon is an example of a ______.
mixture
284
Deuterium and tritium are isotopes of hydrogen. What is different about them?
They have a different number of neutrons
285
What term can be used to describe any molecule that is non-polar and does not dissolve in water?
Hydrophobic
286
What type of ion has lost an electron and, consequently, has a net positive charge?
Cation
287
Which term refers to polar molecules that dissolve in water?
Hydrophilic
288
The chlorine atom gains electrons to become a chloride ______.
anion
289
Saltwater is a solution of NaCl dissolved in water. In this example, NaCl is the solute and water is the ____
solvent
290
In a carbon dioxide molecule, electrons are shared equally among the atoms. What type of bond do they form?
Nonpolar covalent
291
In a solution, the solute can be a ______.
gas, solid, or liquid
292
A(n) ______ consists of substances that are physically blended but not chemically bound.
mixture
293
The abbreviation _____ is a measurement of acidity derived from the concentration of H+.
pH
294
Name a hydrophobic substance
Fats
295
Solution A prevents solution C from changing its pH. Solution A is therefore a what?
Buffer
296
Hydrophilic substances are soluble in ____
water
297
Energy contained in an object due to its position or state is referred to as what type of energy?
Potential
298
In a solution, the more abundant substance that dissolves another substance is known as what?
Solvent
299
The energy of motion is what type of energy?
Kinetic
300
The particles of matter that are dissolved in a solution are known as what?
Solute
301
Which of the following best describes what occurs in a decomposition reaction?
A molecule is broken down into smaller parts.
302
pH is a measurement of the concentration of what?
Hydrogen ions
303
Two amino acids are brought together to form a dipeptide. Which type of reaction is this?
Synthesis
304
Substances that resist changes in pH are known as _____
buffers
305
True or false: Some catalysts speed up reactions, while other catalysts slow down reactions.
False
306
Which term refers to energy in a system that is not being used to do work?
Potential energy
307
The term ______ refers to the sum of all the chemical reactions in the body.
metabolism
308
______ energy is energy that is actively doing work.
Kinetic
309
Which of the following describes a catabolic reaction?
Large protein molecules are broken down into smaller amino acids during digestion.
Reason: Catabolic reactions are decomposition reactions. Larger molecules are broken down into smaller molecules, and energy is released.
310
A chemical reaction in which a larger molecule is broken down into smaller ones is which type of reaction?
Decomposition
311
The term anabolism specifically applies to metabolic reactions that do which of the following?
Build large molecules from small molecules
312
A chemical reaction in which two or more smaller molecules combine to form a larger molecule is what type of reaction?
Synthesis
313
In many biochemical reactions, individual subunits are joined to form larger macromolecules with the release of water molecules. How are these reactions classified?
Dehydration synthesis reactions
314
How do catalysts affect reaction rates?
They increase reaction rates.
315
Name the chemical reaction that breaks a covalent bond in a molecule by adding an OH group to one side of the bond and H to the other side, thus consuming a water molecule.
Hydrolysis
316
Which 3 things are true regarding metabolism?
1) It can be defined as the sum of all of the chemical reactions in the body.
2) It includes reactions where new molecules are synthesized.
3) It includes reactions where molecules are broken down.
317
Which term is used to refer to a simple sugar, or sugar monomer?
Monosaccharide
318
Which term applies to metabolic decomposition reactions that release energy?
Catabolism
319
Name 5 types of lipids
1. Steroids
2. Fatty acids
3. Phospholipids
4. Eicosanoids
5. Triglycerides
320
Metabolic reactions that use energy and build more complex molecules from less complex molecules are considered which type of reaction?
Anabolic
321
A(n) ______ is a lipid that consists of two hydrophobic fatty acid tails and a hydrophilic phosphate head.
phospholipid
322
Sucrose or table sugar is formed when the simple sugars fructose and glucose are covalently bonded. This reaction releases water. What is the name of this type of reaction?
Dehydration synthesis
323
Which of the following best describes the chemical reaction called hydrolysis?
A. A covalent bond is broken by adding an OH to one side of the molecule, and an H to the other side.
B. Two ions join together to form a salt.
C. Electrons are transferred between two molecules.
D. A water molecule is removed from a molecule when it creates a covalent bond.
A. A covalent bond is broken by adding an OH to one side of the molecule, and an H to the other side.
324
Disaccharides can be broken down into ______.
monosaccharides
325
Peptide bonds are used to join two of these together.
Amino acids
326
Hydrophobic organic molecules, such as fatty acids, fats, steroids, and prostaglandins, are classified as what type of molecule?
Lipids
327
```
Which of the following molecules are the major component of the plasma membrane?:
Phospholipids
Steroids
Prostaglandins
Glycoproteins
```
Phospholipids
328
In many biochemical reactions, individual subunits are joined to form larger macromolecules with the release of water molecules. How are these reactions classified?
Dehydration synthesis reactions
329
The ____ structure of a protein is its amino acid sequence.
Primary
330
Name the chemical reaction that breaks a covalent bond in a molecule by adding an OH group to one side of the bond and H to the other side, thus consuming a water molecule.
Hydrolysis
331
Name the type of bond that holds amino acids together in a protein molecule.
Peptide bond
332
The ____ level of protein structure is determined by the folding of the protein due to hydrogen bonding between amino acids to form alpha helices and beta-pleated sheets.
secondary
333
```
Choose the lipids in the list below:
Eicosanoids
Steroids
Phospholipids
Polysaccharides
Polypeptides
Fatty acids
Triglycerides
```
```
Eicosanoids
Steroids
Phospholipids
Fatty acids
Triglycerides
```
334
A(n) _____ is a lipid that consists of two hydrophobic fatty acid tails and a hydrophilic phosphate head.
phospholipid
335
Which level of protein structure is due to bending and folding into various globular and fibrous shapes?
Tertiary
336
The quaternary structure consists of:
the interaction between multiple polypeptide subunits.
337
What does the quaternary structure of a protein depend upon?
Interactions between multiple polypeptide chains
338
Which of the following best describes the chemical reaction called hydrolysis?
A covalent bond is broken by adding an OH to one side of the molecule, and an H to the other side.
339
Which term refers to a change in the three-dimensional conformation of a protein that destroys its functional properties?
Denaturation
340
Name the level of protein structure that is determined by the folding of the protein into alpha helices and beta sheets due to hydrogen bonding between amino acids.
Secondary
341
A _____ is the substance that an enzyme acts upon.
substrate
342
Hydrophobic organic molecules, such as fatty acids, fats, steroids, and prostaglandins, are classified as what type of molecule?
Lipids
343
Which of the following is another term for enzyme?
Biological catalyst
344
The folding of proteins into various globular and fibrous shapes is referred to as the
____ structure of the proteins.
tertiary
345
Which term refers to the energy needed to get a chemical reaction started?
Activation energy
346
The _____ level of protein structure is determined by the interactions between two or more polypeptide chains within a protein.
quaternary
347
Which of the following statements about enzymes are true?:
Enzymes speed up reaction rates by lowering the activation energy of a specific reaction.
Enzymes show enzyme-substrate specificity.
Enzymes may act as reactants in the reactions they catalyze.
Enzymes are not affected by pH.
Enzymes are not consumed in the reactions they catalyze.
Enzymes speed up reaction rates by lowering the activation energy of a specific reaction.
Enzymes show enzyme-substrate specificity.
Enzymes are not consumed in the reactions they catalyze.
348
Which of the following best describes denaturation?
The unfolding of a protein's three-dimensional shape
349
Which term refers to the substance upon which an enzyme acts?
Substrate
350
Indicate how pH and temperature affect the activity of an enzyme:
Altering the enzyme concentration
Altering the shape of the substrate binding site
Altering the substrate concentration
Causing a conformational change in the enzyme
Altering the shape of the substrate binding site
| Causing a conformational change in the enzyme
351
A(n) _____ is a protein that functions as a biological catalyst.
enzyme
352
Which is an example of a nucleotide?
ATP
353
What effect do enzymes have on the activation energy of a chemical reaction in the body?
Enzymes lower activation energy
354
True or false: An enzyme is consumed by the reaction it catalyzes.
False
355
Which term refers to a change in the three-dimensional conformation of a protein that destroys its functional properties?
Denaturation
356
Which of the following factors affect enzyme conformation?:
Temperature
Enzyme concentration
pH
Temperature & pH
357
Which organic molecules are composed of a nitrogenous base, a monosaccharide, and a phosphate group?
Nucleotides
358
Nucleotides contain a phosphate, a sugar and a nitrogenous _____
base
359
Which is an example of a nucleotide?
ATP
360
True or false: All organisms are composed of cells
True
361
____ are responsible for all structural and functional properties of a living organism
Cells
362
Understanding cells is the key to understanding what three things?
Workings of human body
Mechanisms of disease
Rationale of therapy
363
What are the 5 components of cell theory?
1) All organisms composed of cells and cell products
2) Cell is the simplest structural and functional unit of life
3) An organism’s structure and functions are due to activities of cells
4) Cells come only from preexisting cells
5) Cells of all species exhibit biochemical similarities
364
How many types of cells are there in the human body?
About 200 different types
365
What does the plasma (cell) membrane do and what is it made up of?
It surrounds cell and defines boundaries. Made of proteins and lipids
366
What 4 things are included in the cytoplasm?
1) Organelles
2) Cytoskeleton
3) Inclusions (stored or foreign particles)
4) Cytosol (intracellular fluid, ICF)
367
True or false: extracellular fluid (ECF) is one of the basic components of a cell
True
368
Define organelle
Internal structures of a cell that carry out specialized metabolic tasks
369
What’s the difference between cytoplasm and cytosol?
Cytoplasm contains the organelles; cytosol does not.
370
How is the plasma membrane arranged?
In a bilayer
371
What is the border of the cell?
The plasma membrane
372
Name 3 functions of the plasma membrane
1) Defines cell boundaries
2) Governs interactions with other cells
3) Controls passage of materials in and out of cell
373
__% of membrane molecules are lipids
98%
374
What are the 3 most abundant membrane lipids?
Phospholipids (75% of membrane lipids), cholesterol (20%), and glycolipids (5%)
375
What does the membrane lipid cholesterol do?
Holds phospholipids still and can stiffen the membrane
376
What are glycolipids?
Phospholipids with short carbohydrate chains on extracellular face. A type of membrane lipid.
377
Membrane proteins make up __% of the molecules but __% of the weight of membrane
2% of the molecules but 50% of the weight of membrane
378
What are the two basic types of membrane proteins, and where are they located?
Integral proteins—penetrate membrane
| Peripheral proteins – on the surface of membrane
379
What is one type of integral protein?
Transmembrane proteins
380
________ proteins contain both hydrophilic and hydrophobic regions
Transmembrane
381
Where are transmembrane proteins located?
Some drift in membrane; others are anchored to cytoskeleton
382
Describe peripheral proteins
- Adhere to one face of the membrane (do not penetrate it)
| - Usually tied to the cytoskeleton and an integral protein.
383
What are some examples of the functions of membrane proteins?
Receptors, enzymes, channels, carriers, cell-identity markers, cell-adhesion molecules, etc
384
What is the glycoalyx? What is it made up of?
It's a fuzzy coat external to plasma membrane, and made up of glycoproteins and glycolipids
385
_______ is unique in everyone but identical twins
Glycocalyx
386
What does the glycocalyx do?
It helps with protection, immunity to infection, defense against cancer, transplant compatibility, cell adhesion, fertilization, and embryonic development
387
True or false: Some channel proteins are always open, but others are gated
True
388
What are channel proteins needed for?
They're crucial to nerve and muscle function
389
What are 3 different types of channel proteins?
Ligand-gated channels, voltage gated channels, and mechanically-gated channels
390
Ligand-gated channels respond to _____
chemical messengers
391
Voltage-gated channels respond to ____
charge changes
392
Mechanically-gated channels respond to ____
physical stress on the cell
393
What is an example of a stretch receptor?
Mechanically-gated channels
394
Give an example of chemical messengers for ligand-gated channels
Neurotransmitters
395
Microvilli are best developed in cells specialized in _____
absorption
396
What are microvilli?
Extensions of the membrane that gives 15 to 40 times more surface area
397
How big are microvilli?
1-2μm
398
What is it called when microvilli are very dense and appear as a fringe?
Brush border
399
What are cilia?
Hair-like processes that are 7–10 μm long
400
What is one type of cilia?
Motile cilia
401
____ cilia are found in the respiratory tract, uterine tubes, ventricles of brain, ducts of testes
Motile cilia
402
What do cilia do?
Beat in waves sweeping material across a surface in one direction
403
True or false: the flagellum of sperm is the only functioning flagella in humans
True
404
Describe the structure and movement of flagella
They have a whip-like structure and are much longer than cilium.
Their movement is undulating, snake-like, corkscrew; no power stroke and recovery strokes
405
What are pseudopods?
Continually changing extensions of the cell that vary in shape and size
406
What can pseudopods do?
They can be used for cellular locomotion or capturing foreign particles
407
The plasma membrane is selectively permeable. What does this mean?
It allows some things through, but prevents others from passing
408
Which of the following mechanisms consume ATP?:
a) passive transport
b) active transport
c) both active and passive transport
b) active transport
409
What does passive transport not require any of the cell's energy?
Random molecular motion of particles provides necessary energy
410
Is membrane transport a type of passive or active transport?
It can be either passive or active
411
Define membrane transport
Carrier-mediated mechanisms use a membrane protein to transport substances across membrane
412
Name 4 passive mechanisms of transportation
1) Filtration
2) Simple Diffusion
3) Facilitated Diffusion
4) Osmosis
413
Define filtration
A type of passive transport, particles are driven through membrane by physical pressure
414
Where can filtration be found in the human body? (3 examples)
1) Filtration of water and small solutes through gaps in capillary walls
2) Allows delivery of water and nutrients to tissues
3) Allows removal of waste from capillaries in kidneys
415
Define a gradient
A difference in chemical concentration, charge, temperature, or pressure between two points
416
True or false: Matter and energy tend to flow up gradients
False; matter and energy tend to flow DOWN gradients
417
Give an example of matter flowing down a gradient in the body
Blood flows from a place of higher pressure to a place of lower pressure
418
Moving up a gradient requires what?
Energy
419
Define simple diffusion
The net movement of particles from place of high concentration to place of lower concentration
420
Why does simple diffusion happen?
It happens due to constant, spontaneous molecular motion; molecules collide and bounce off each other
421
Substances diffuse ____ their concentration gradient
down
422
When can substances diffuse through a membrane?
If the membrane is permeable to the substance
423
True or false: the diffusion of substances down a concentration gradient doesn't require a membrane
True
424
In _____ diffusion, the substance passes directly through the phospholipid bilayer
simple
425
What 5 factors affect the diffusion rate through the membrane?
1) Temperature: ^ temp = ^ motion of particles = ^ rate
2) Molecular weight: larger molecules move slower
3) Steepness of concentrated gradient: ^ difference = ^ rate
4) Membrane surface area: ^ area = ^ rate
5) Membrane permeability: ^ permeability = ^ rate
426
Define osmosis
The diffusion of water through a selectively permeable membrane
427
In osmosis, water moves from the side where water is ____ concentrated to the side where it is ____ concentrated
more; less
428
Will osmosis speed up or slow down if a cell adds more aquaporins?
Speed up
429
Define aquaporins
Channel proteins in a membrane specialized for water passage
430
Define osmolarity
The measure of total concentration of solute particles
431
Define tonicity
The concentration of non-permeating solutes
432
Define hypotonic solution
A solution that has a lower concentration of non-permeating solutes than the other solution
433
Define a hypertonic solution
A solution that has a higher concentration of non-permeating solutes than the other solution
434
Define an isotonic solution
Where concentrations of non-permeating solutes in both solutions are the same
435
What happens to a cell if it's placed in a hypertonic solution?
Water diffuses out of the cell and causes crenation (shriveling) because now it doesn't have enough water
436
What happens to a cell if it's place in a hypotonic solution?
Water diffuses into the cell and causes hemolysis (explosion) because now it has too much water.
437
What happens to a cell if it's placed in an isotonic solution?
Nothing, stays the same
438
What are the three mechanisms of carrier-mediated transport?
1) Facilitated diffusion
2) Primary active transport
3) Secondary active transport
439
What is carrier-mediated transport?
Solute attaches to binding site on carrier, carrier changes conformation, then releases solute on other side of membrane
440
Describe facilitated diffusion
- Carrier moves the solute down its concentration gradient
| - Does not consume ATP
441
Describe primary active transport
- Carrier moves the solute through a membrane up (against) its concentration gradient
- Need ATP for energy
442
True or false: facilitated diffusion doesn't require ATP
True
443
Give 2 examples of primary active transport in the body
- Calcium pump (uniport)
| - Sodium–potassium pump (antiport)
444
What does the sodium-potassium pump do, and why?
- Three Na+ are pumped out and two K+ are pumped in by the sodium potassium pump
- Necessary because Na+ and K+ constantly leak through membrane
445
Define vesicular transport
Moves large particles, fluid droplets, or numerous molecules at once through the membrane in vesicles—bubble-like enclosures of membrane
446
Define endocytosis
Transports material into cell
447
Define exocytosis
Transports material out of the cell
448
Define transcytosis
Transport into, across, and then out of a cell
449
What are the two types of endocytosis? Describe them
Phagocytosis—“cell eating,” engulfing large particles
| Pinocytosis—“cell drinking,”
450
What does phagocytosis do?
Phagocytosis keeps tissues free of debris and infectious microbes
451
Describe receptor-mediated endocytosis
- More selective endocytosis
| - Enables cells to take in specific molecules that bind to extracellular receptors
452
Describe exocytosis and when it's needed (before or after endocytosis)
- Secreting material
| - Needed in the replacement of plasma membrane removed by endocytosis (after endocytosis)
453
What materials in the body can be released by exocytosis?
- Ejection of wastes
- Release of neurotransmitters
- Hormone secretion
- Mucus secretion
454
What is the cytoskeleton?
A network of protein filaments and cylinders
455
What is the largest organelle (5 μm in diameter)?
The nucleus
456
Most cells have how many nuclei?
1
457
True or false: cells can be mononuclear, polynuclear, or anuclear
True
458
Give an example of an anuclear cell in humans
Red blood cells
459
Give an example of a cell with many nuclei (a polynuclear cell) in the human body
Skeletal muscle cells & some bone dissolving cells
460
Define the nuclear envelope
A double membrane with pores surrounding the nucleus
461
Nucleoplasm is made up of what two things?
Chromatin and nucleoli
462
Define chromatin
A thread-like substance composed of DNA and protein; one of two substances that makes up nucleoplasm
463
Define nucleoli
Masses where ribosomes are produced; one of two substances that makes up nucleoplasm
464
Define endoplasmic reticulum
A system of channels (cisternae) enclosed by membrane
465
What makes up the rough endoplasm reticulum and what does it do?
It's made up of parallel, flattened sacs covered with ribosomes.
Functions: protein synthesis and packages proteins for transport
466
The ___ endoplasmic reticulum has ribosomes, whereas the ____ endoplasmic reticulum doesn't
The rough endoplasmic reticulum has ribosomes; the smooth endoplasmic reticulum doesn't
467
What does the smooth endoplasmic reticulum do? (three things)
1) Synthesizes steroids and other lipids
2) Detoxifies alcohol and other drugs
3) Calcium storage
468
What are ribosomes?
Small granules of protein and RNA
469
What do ribosomes do?
They “read” coded genetic messages (messenger RNA) and assemble amino acids into proteins specified by the code
470
What does the golgi complex do?
It receives newly synthesized proteins from rough ER. Then it sorts proteins, modifies proteins, and packages them into vesicles
471
What do vesicles become/do after leaving the golgi complex?
Some vesicles become lysosomes
Some vesicles migrate to plasma membrane and fuse to it
Some become secretory vesicles that store a protein product for later release
472
Define lysosomes
A package of enzymes bound by a membrane
473
What 3 things do lysosomes do?
1. Intracellular hydrolytic digestion
2. Phagocytosis
3. Autolysis
474
Define autolysis
"Cell suicide” or the digestion of a surplus cell by itself
475
What are peroxisomes and what do they do?
Resemble lysosomes but contain different enzymes. They detoxify certain harmful chemicals, enclose reactions that make toxic byproducts
476
Peroxisomes are found in all cells, but are especially abundant in what two organs?
The liver and kidney
477
Define mitochondria
Organelles specialized for synthesizing ATP
478
Mitochondria are surrounded by a ____ membrane
double
479
What makes mitochondrial DNA (mtDNA) unique, and what does it do?
It mutates more rapidly than nuclear DNA; continually changes shape from spheroidal to thread-like. It's responsible for hereditary diseases affecting tissues with high energy demands
480
What do centrioles do?
They form the mitotic spindle during cell division, unpaired centrioles form basic structure of cilia and flagella
481
Define (simple) diffusion
The net movement of particles from place of high concentration to place of lower concentration
482
Define osmosis
The diffusion of water through a selectively permeable membrane from an area of high concentration to an area of low concentration
483
Define (primary) active transport
A carrier moves the solute through a membrane up (against) its concentration gradient
484
Extracellular fluid is ____ the cell, whereas intracellular fluid is ____ the cell.
Extracellular fluid is outside the cell, whereas intracellular fluid is inside the cell
485
What is the most abundant cation in extracellular fluid? Most abundant anion?
Cation: Na+
Anion: Cl-.
486
What is the most abundant cation in intracellular fluid? Most abundant anion?
Cation: K+
Anions: proteins, atp
487
Define tonicity
The concentration of non-permeating solutes (solutes that cannot pass through the membrane)
488
Two major extracellular fluids are
Plasma and interstitial fluid
489
Name 4 passive mechanisms of transportation
1) Filtration
2) Simple Diffusion
3) Facilitated Diffusion
4) Osmosis
490
Define a gradient
A difference in chemical concentration, charge, temperature, or pressure between two points
491
True or false: Matter and energy tend to flow up gradients
False; matter and energy tend to flow DOWN gradients
492
Give an example of matter flowing down a gradient in the body
Blood flows from a place of higher pressure to a place of lower pressure
493
Moving up a gradient requires what?
Energy
494
Define hypotonic solution
A solution that has a lower concentration of non-permeating solutes than the other solution
495
Define a hypertonic solution
A solution that has a higher concentration of non-permeating solutes than the other solution
496
Define an isotonic solution
Where concentrations of non-permeating solutes in both solutions are the same
497
What happens to a cell if it's placed in a hypertonic solution?
Water diffuses out of the cell and causes crenation (shriveling) because now it doesn't have enough water
498
What happens to a cell if it's place in a hypotonic solution?
Water diffuses into the cell and causes hemolysis (explosion) because now it has too much water.
499
What happens to a cell if it's placed in an isotonic solution?
Nothing, stays the same
500
How can water flow quickly into cells?
Facilitated diffusion through aquaporins
501
```
The plasma membrane is made up of phospholipids and which of the following?
Protein
Calcium
Carbohydrates
Cellulose
```
Protein
502
What is the simplest structural and functional unit of living things?
Cells
503
What do voltage-gated ion channels open in response to?
A change in membrane potential
504
Cells that line the intestine are taller than they are wide and therefore described as what?
Columnar
505
Tissue fluid is also called ______.
Interstitial fluid
506
Which cellular structure is critical for identifying your body's own healthy cells from transplanted tissue?
Glycocalyx
507
The majority of the plasma membrane can be described as a bilayer of
_____ with associated proteins.
phospholipids
508
Extensions of the cell membrane that serve to increase surface area are called
Microvilli
509
Squamous cells line the ____
esophagus
510
When the concentration of a substance differs from one area to another, this creates a concentration
gradient
511
Smaller molecules diffuse ______ larger molecules.
faster than
512
A membrane coating called the
| ______ is chemically unique in everyone but identical twins.
glycocalyx
513
```
Water and electrolytes can cross a cell membrane through which of the following?
Transporters
Vesicles
Cholesterol molecules
Channels
```
Channels
514
Extensions of the plasma membrane that serve primarily to increase a cell's surface area are called ______.
microvilli
515
Plasma membranes are selectively permeable. What does this mean?
Some compounds can permeate (pass through) the membrane while others cannot.
516
The movement of water in and out of the renal tubules can be increased or decreased. The tubular cells are able to do this, by changing the number of water channels, also called
_____ in their membranes.
aquaporins
517
A(n) ______ solution has a lower osmotic pressure than the intracellular fluid of the cell and tends to cause osmotic swelling and lysis of cells.
hypotonic
518
Which factors would increase the rate of diffusion?
Decreased temperature
Decreased molecular weight of diffusing compound
Increased concentration difference
Increased cell surface area
Decreased molecular weight of diffusing compound
Increased concentration difference
Increased cell surface area
519
A cell placed into which solution will lose water by osmosis?
Isotonic
Hypertonic
Hypotonic
Hypertonic
520
```
Which of the following molecules can readily diffuse through a cell membrane?
Lipid-soluble molecules
Hydrophobic molecules
Nonpolar molecules
Large hydrophilic molecules
```
Lipid-soluble molecules
Hydrophobic molecules
Nonpolar molecules
521
What is a protein that participates in transmembrane transport called?
A carrier
522
What are the membrane channels that allow the movement of water across a membrane called?
Aquaporins
523
When all carriers are saturated, the transport of the molecule levels off at a rate called what?
Transport maximum
524
Cells placed in a(n) ______ solution will swell and burst due to water moving into the cell.
hypotonic
525
A(n) ____ solution has a higher osmotic pressure than the intracellular fluid of cells and tends to cause the cells to undergo osmotic shrinkage.
hypertonic
526
```
Mechanisms for moving substances across the plasma membrane that require the use of cellular ATP include which of the following:
vesicular transport
passive diffusion
osmosis
active transport
```
vesicular transport and active transport
527
The Na+-K+ pump moves ______ Na+ ions from the ICF to the ECF while simultaneously moving ______ K+ ions from the ECF into the ICF.
3; 2
528
In which process does a solute bind to a carrier in the plasma membrane that then changes shape and releases the solute to the other side of the membrane?
Carrier-mediated transport
529
The general term for the cell process in which the membrane invaginates, forming vesicles that bring extracellular particles or droplets of fluid into the cell, is known as ___
endocytosis
530
The Na+-K+ pump is a good example of which type of transport?
Primary active transport
531
Which cytoskeletal elements resist stresses placed on a cell and participate in junctions that attach some cells to their neighbors?
Intermediate filaments
532
What are the three types of endocytosis?
Pinocytosis, phagocytosis, and receptor-mediated
533
The organelle which controls cellular activity is the
Nucleus
534
The process of using a carrier to passively transport a solute through a membrane down its concentration gradient is known as
____ diffusion.
facilitated
535
Which of the following best defines chromatin?
Particles on the surface of rough endoplasmic reticulum
Tubular structures forming the centrioles
Folds of the inner membrane within mitochondria
Fine threads of DNA and protein
Fine threads of DNA and protein
536
The vesicular transport process of discharging material from a cell is called
exocytosis
537
What is the function of the smooth endoplasmic reticulum?
To synthesize lipids
538
_____ filaments are thicker and stiffer than microfilaments and participate in cell-to-cell adhesion.
Intermediate
539
What is the large centrally-located organelle visible with a light microscope called?
Nucleus
540
Where are proteins, such as enzymes, that are to be secreted from the cells produced?
Ribosomes on the ER
541
The fine thread-like genetic material (the form of DNA) found within the nucleus of a non-dividing cell is called
chromatin
542
The organelle that resembles stacked membranous sacs and is involved in "packaging" is the _____ complex.
golgi
543
Which membrane-bound organelle contains a mixture of enzymes that function in digesting foreign matter, pathogens, and expired organelles?
Lysosome
544
What is the function of the rough endoplasmic reticulum?
To synthesize proteins
545
Which cytoskeletal elements resist stresses placed on a cell and participate in junctions that attach some cells to their neighbors?
Intermediate filaments
546
Which organelle contains enzymes needed to neutralize free radicals, detoxify alcohol, other drugs, and blood-borne toxins?
Peroxisome
547
______ are the organelles that read coded genetic messages and assemble amino acids into proteins.
Ribosomes
548
Which organelle is comprised of stacked cisternae that synthesize carbohydrates?
Golgi complex
549
Which organelle is has a double unit membrane?
Mitochondria
550
_____ are the organelles that digest and dispose of worn-out mitochondria and other organelles by a process called autophagy.
Lysosomes
551
Which organelles participate in cell division?
Centrioles
552
Which endoplasmic reticulum has tubular, branched cisternae, and lacks ribosomes?
Smooth ER
553
The membrane-bound organelle that contains enzymes and oxygen used to oxidize organic material is the _____
peroxisome
554
Which of the following are small granules of RNA and protein that provide a site for protein synthesis?
Ribosomes
555
Basal bodies and the axonemes of flagella and cilia originate from which non-membranous organelles?
Centrioles
556
Which of the following is a short cylindrical assembly of microtubules arranged in nine groups of three?
Centrioles
557
What are the three major regions of a cell?
Plasma membrane, cytoplasm, and nucleus
558
What are the main components of the plasma membrane?
Phospholipids, proteins, and carbohydrates attached to some of the lipids and proteins.
559
What is selective permeability?
When some substances can pass through a membrane but not others
560
Define primary active transport
A carrier protein moves the solute through a membrane up (against) its concentration gradient. This process requires ATP from the cell.
561
Define passive transport
The movement of a molecule down its concentration gradient and across a membrane without the use of ATP
562
Define simple diffusion
The net movement of particles from place of high concentration to place of lower concentration
563
Define facilitated diffusion
A carrier protein moves the solute down its concentration gradient, and does not consume ATP
564
What's the difference between simple diffusion and facilitated diffusion?
Facilitated diffusion requires a carrier protein
565
Define the nucleus
The "brain" of a cell
566
Define the nuclear envelope
A double membrane with pores surrounding the nucleus
567
Define nucleolus/ nucleoli
Masses where ribosomes are produced
568
Define chromatin
A thread-like substance composed of DNA and protein; one of two substances that makes up nucleoplasm
569
What’s the difference between cytoplasm and cytosol?
Cytoplasm contains the organelles; cytosol does not.
570
What is included in the cytoplasm?
–Organelles
–Cytoskeleton
–Inclusions (stored or foreign particles)
–Cytosol (intracellular fluid, ICF)
571
Define cytosol
The aqueous component of the cytoplasm of a cell
572
Which organelle is best described as system of channels (cisternae) enclosed by a membrane?
The endoplasmic reticulum
573
Which organelle is best described as parallel, flattened sacs covered with
ribosomes?
Rough ER
574
What does the rough ER do?
Protein synthesis and packages proteins for transport
575
What does the smooth ER do?
–Synthesizes steroids and other lipids
–Detoxifies alcohol and other drugs
–Calcium storage
576
What do ribosomes do?
They “read” coded genetic messages
(messenger RNA) and assemble amino acids
into proteins specified by the code
577
Which organelle is best described as small granules of protein and
RNA?
Ribosomes
578
What does the golgi complex do?
•Receives newly synthesized proteins from
rough ER
•Sorts proteins, modifies proteins, and
packages them into vesicles
–Some vesicles become lysosomes
–Some vesicles migrate to plasma membrane and fuse to it
–Some become secretory vesicles that store a protein product for later release
579
Which organelle is best described as an organelle
| specialized for synthesizing ATP?
Mitochondria
580
What do mitochondria do?
They make ATP
581
What do centrioles do?
They form the mitotic spindle during cell division,
| unpaired centrioles form basic structure of cilia and flagella
582
Which organelle is best described as a package of enzymes bound by a membrane?
Lysosomes
583
What do lysosomes do?
–Intracellular hydrolytic digestion
–Phagocytosis
–Autolysis
584
What do peroxisomes do?
Detoxify certain harmful chemicals, enclose
| reactions that make toxic byproducts
585
What does the plasma membrane do?
•Defines cell boundaries
•Governs interactions with other cells
•Controls passage of materials in and out of
cell
586
Which organelle would best be described as the border of the cell (arranged in bilayer)?
Plasma membrane
587
Give 4 examples of genetic disorders that can impact hereditary traits.
Color blindness, cystic fibrosis, diabetes mellitus, and hemophilia
588
Define DNA
A long, thread-like molecule with uniform diameter, but varied length
589
There are ___ DNA molecules (chromosomes) in nucleus of most human cells
46
590
DNA and other nucleic acids are polymers of ______
nucleotides
591
Nucleotides consist of what 3 things?
A sugar, phosphate group, and nitrogenous base
592
Give an example of a type of sugar that can be found in nucleotides
Deoxyribose
593
What are the two types of nitrogenous bases in nucleic acids?
1) Purines
| 2) Pyrimidines
594
What distinguishes purines and pyrimidines from each other?
Purines have a double ring, pyrimidines have a single ring
595
Which bases are purines and which bases are pyrimidines?
1) Purines - adenine (A) and guanine (G)
| 2) Pyrimidines - cytosine (C), thymine (T), and uracil (U)
596
What are the 4 bases found in DNA? What are the 4 bases found in RNA?
DNA bases: A, T, C, G
| RNA bases: A, U, C, G
597
DNA has a ______ _____ shape.
double helix
598
The nitrogenous bases of DNA are united by ______ bonds
hydrogen
599
True or false: A purine on one strand always bound to a pyrimidine on the other
True
600
In DNA, the base A always pairs with ___ and G always pairs with ___
A - T & G - C
601
A–T has ___ hydrogen bonds
| C–G has ___ hydrogen bonds
A–T has two hydrogen bonds
| C–G has three hydrogen bonds
602
What is the law of complementary base pairing?
The idea that one strand determines base sequence of other
603
Define chromatin
Fine filamentous DNA material complexed with proteins
604
Define a gene using two different definitions
1) A segment of DNA coding for the synthesis of a specific protein.
2) An information-containing segment of DNA that codes for synthesizing one or more proteins
605
Define genome
All the genes of one person
606
Humans have about _____ genes
20,000
607
Genes only make up ____% of total DNA, the rest is noncoding DNA.
2%
608
___ interprets the code in ___ to synthesize proteins
RNA interprets the code in DNA to synthesize proteins
609
RNA functions mainly in the _____
cytoplasm
610
What are the 3 important types of RNA for protein synthesis?
- Messenger RNA (mRNA)
- Ribosomal RNA (rRNA)
- Transfer RNA (tRNA)
611
In what 4 ways does RNA differ from DNA?
1) Single stranded (one nucleotide chain not a double helix like DNA)
2) Ribose replaces deoxyribose as the sugar
3) Uracil replaces thymine as a nitrogenous base
4) Functions mainly in cytoplasm
612
What determines the amino acid sequence of a protein?
The nucleotide sequence in the DNA
613
The minimum code to symbolize 20 amino acids is ____ nucleotides per amino acid
three
614
The body can make millions of different proteins based on only ___ amino acids and is encoded by genes made of just ___ nucleotides
The body can make millions of different proteins based on only 20 amino acids and is encoded by genes made of just four nucleotides
615
Define a base triplet
A sequence of three DNA nucleotides that stands for one amino acid
616
Define a codon
The 3-base sequence in mRNA
617
How many codons are there?
64 possible codons available to represent the 20 amino acids.
618
__ codons code for amino acids; __ are stop codons
61 codons code for amino acids; 3 are stop codons
619
What are stop codons?
They signal “end of message”
620
What are start codons?
AUG codes for methionine, and begins the amino acid sequence of the protein
621
Define transcription
Copying genetic instructions from DNA to mRNA
622
Define RNA polymerase
An enzyme that binds to DNA and assembles mRNA
623
How does RNA polymerase assemble mRNA?
1) RNA polymerase reads bases from one strand of DNA
| 2) Makes corresponding mRNA
624
What is translation?
The process that converts the language of nucleotides into the language of amino acids
625
What 3 things participate in the process of translation?
mRNA, tRNA, and ribosomes
626
Briefly describe the process of translation
1) mRNA carries code from nucleus to cytoplasm
2) Transfer RNA (tRNA) delivers a single amino acid to the ribosome for it to be added to growing protein chain
3) Ribosome adds the amino acid to the protein chain.
627
_RNA contains an anticodon that are complementary to codon of mRNA
tRNA
628
Where are ribosomes found and what are they made of?
1) Found free in cytosol, on rough ER, and on nuclear envelope
2) Consist of enzymes and ribosomal RNA (rRNA)
629
Describe the structure of tRNA
1) One end includes three nucleotides called an anticodon
| 2) Other end has binding site specific for one amino acid
630
What are the 3 steps to translation?
Initiation, Elongation, and Termination
631
Describe the step of initiation (3 parts)
1) Initiator tRNA (bearing methionine) pairs with start codon
2) Ribosome pulls mRNA molecule through it like a ribbon
3) When start codon (AUG) is reached, protein synthesis begins
632
Describe the step of elongation (6 parts)
1) Next tRNA (with its amino acid) binds to ribosome while its anticodon pairs with next codon of mRNA
2) Peptide bond forms between methionine and second amino acid
3) Ribosome slides to read next codon
4) Next tRNA with appropriate anticodon brings its amino acid to ribosome
5) Another peptide bond forms (between 2nd and 3rd amino acids)
6) Process continually repeats, extending peptide to a protein
633
Describe the step of termination (3 steps)
1) Ribosome reaches stop codon
2) Finished protein breaks away from ribosome
3) Ribosome dissociates into two subunits
634
Describe DNA replication (4 steps)
1) DNA unwinds from histones
2) An enzyme unzips a segment of the double helix exposing its nitrogenous bases
3) DNA polymerase builds new DNA strands
4) Newly made DNA wraps around histones
635
Before a cell divides, it must duplicate its DNA. Why?
So it can give a complete copy of all its genes to each daughter cell
636
When preparing to divide, the cell makes copy of ____ DNA
nuclear
637
When preparing to divide, after nucelar DNA is replicated, each chromosome then consists of two parallel filaments of identical DNA called ______
Sister chromatids
638
Where are chromatids joined?
At the centromere
639
Define cell cycle
A cell’s life from one division to the next
640
What are the two main parts of the cell life cycle?
Interphase and mitotic phase
641
What does interphase of the cell cycle include
1) G1: first gap phase
2) S: synthesis phase
3) G2: second gap phase
642
What does the mitotic phase of the cell cycle include?
Prophase, Metaphase, Anaphase, Telophase
643
Describe G1 of interphase
- The first gap phase; the interval between cell birth (from division) and DNA replication
- Cell carries out normal tasks and accumulates materials for next phase
644
Describe the S stage of interphase
Synthesis phase; the cell replicates all nuclear DNA and duplicates centrioles
645
Describe G2 of interphase
- The second gap phase; the interval between DNA replication and cell division
- Cell repairs DNA replication errors, grows and synthesizes enzymes that control cell division
646
Briefly describe the mitotic phase of cell division
The cell replicates its nucleus and pinches in two to form new daughter cells
647
What is the G0 phase?
Describes cells that have left the cycle and cease dividing for a long time (or permanently)
648
True or false: Cell cycle duration varies between cell types
True
649
Define mitosis
Mitosis is cell division resulting in two genetically identical daughter cells
650
What are the 4 main functions of mitosis?
1) Development of the individual from one fertilized egg to roughly 50 trillion cells
2) Growth of all tissues and organs after birth
3) Replacement of cells that die
4) Repair of damaged tissues
651
What are the 4 stages of mitosis/ the mitotic phase?
Prophase, metaphase, anaphase, telophase
652
Describe the prophase stage of mitosis (6 steps)
1) Genetic material condenses into compact chromosomes
2) 46 chromosomes are made of two sister chromatids
3) Nuclear envelope disintegrates
4) Centrioles sprout spindle fibers (long microtubules)
5) Spindle fibers push centriole pairs apart
6) Some spindle fibers attach to kinetochores of centromeres of chromosomes
653
Describe the metaphase stage of mitosis (2 steps)
- Chromosomes are aligned on cell equator
| - Shorter microtubules from centrioles complete an aster which anchors itself to inside of cell membrane
654
Describe the anaphase stage of mitosis (2 steps)
- Enzyme cleaves two sister chromatids apart at centromere
- Single-stranded daughter chromosomes migrate to each pole of the cell as motor proteins in kinetochores crawl along spindle fibers
655
Describe the telophase stage of mitosis (5 steps)
- Chromosomes cluster on each side of the cell
- Rough ER makes new nuclear envelope around each cluster
- Chromosomes uncoil to chromatin
- Mitotic spindle disintegrates
- Each nucleus forms nucleoli
656
Define cytokinesis
The division of cytoplasm into two cells
657
True or false: Telophase is the end of nuclear division but overlaps cytokinesis
True
658
Describe the stage of cytokinesis (2 steps)
1) Creates cleavage furrow around the equator of cell
| 2) Cell eventually pinches in two
659
Cells replicate under what conditions?
Cells replicate if:
- They have enough cytoplasm for two daughter cells
- They have replicated their DNA
- They have adequate supply of nutrients
- They are stimulated by growth factors (chemical signals)
- Neighboring cells die, opening up space
660
Cells stop dividing under what conditions?
1) They snugly contact neighboring cells
2) Nutrients or growth factors are withdrawn
3) They undergo contact inhibition—the cessation of cell division in response to contact with other cells
661
```
Which of the following are components of nucleotides?
Phosphate groups
Nitrogenous bases
Sugars (ribose or deoxyribose)
Amino acids
Proteins
```
Phosphate groups
Nitrogenous bases
Sugars (ribose or deoxyribose)
662
In DNA, the base adenine pairs with the base ____
thymine
663
How many hydrogen bonds do adenine and thymine form with each other?
Two
664
In the nucleus, DNA is complexed with proteins to form a fine filamentous material called _____
chromatin
665
In the nucleus of a typical human cell, there are 46 DNA filaments. Which term refers to one of these structures?
Chromosome
666
Which of the following best describes a histone?
1) A protein component of chromatin that helps to organize and package DNA
2) The pinched spot on the chromosome where two sister chromatids join together
3) A long, noncoding sequence of DNA
4) A segment of the DNA that carries the genetic code for a particular protein
1) A protein component of chromatin that helps to organize and package DNA
667
When a cell is preparing to divide, it makes an exact copy of all its nuclear DNA. Each chromosome then consists of two parallel filaments called _____ chromatids
sister
668
How many hydrogen bonds do guanine and cytosine form with each other?
3
669
Which of the following is true about the centromere?
a) It is what chromosomes attach to, so they can be pulled to the middle of the cell.
b) It is located at the tips of the chromosome "arms".
c) It is where sister chromatids are joined together.
d) It is a short stretch of DNA wrapped around a cluster of histone proteins.
c) It is where sister chromatids are joined together.
670
Which term refers to the filamentous material composed of DNA and associated proteins that is found in the nucleus of a cell?
a) Centrioles
b) Chromatids
c) Chromatin
d) Chromosome
c) Chromatin
671
mRNA is short for ____ RNA
messenger
672
In the nucleus of a dividing cell, the chromatin condenses so that each _____ is now made of two sister chromatids, can be seen with a light microscope.
chromosome
673
```
Histones are ______.
triglycerides
proteins
carbohydrates
nucleic acids
```
proteins
674
How are DNA and RNA different?
A) RNA consists of only one nucleotide chain whereas DNA is a double helix.
B) RNA contains a sugar called ribose whereas DNA contains a sugar called deoxyribose.
C) RNA contains adenine, cytosine, thymine and guanine whereas DNA contains adenine, cytosine, thymine and uracil.
D) RNA is much smaller. DNA, by contrast, averages more than 100 million base pairs long.
A) RNA consists of only one nucleotide chain whereas DNA is a double helix.
B) RNA contains a sugar called ribose whereas DNA contains a sugar called deoxyribose.
D) RNA is much smaller. DNA, by contrast, averages more than 100 million base pairs long.
675
```
When a cell is preparing to divide, it makes an exact copy of all its nuclear DNA. Each chromosome then consists of two parallel filaments called what?
Chromatin
Sister chromatids
Base pairs
Histone groups
```
Sister chromatids
676
A(n) ______ is an information-containing segment of DNA that codes for the production of a molecule of RNA, and that in most cases codes for one or more proteins.
gene
677
```
A centromere holds _______ together.
proteins
kinetochores
sister chromatids
RNA
```
sister chromatids
678
Which of the following are true statements about the genetic code?
a) The genetic code relates mRNA codons to protein structure.
b) Each codon in the genetic code can stand for two or more amino acids.
c) The genetic code is expressed as three-nucleotide long sequences called codons.
d) The genetic code allows 20 amino acid to be coded by only 4 different nucleotides.
a) The genetic code relates mRNA codons to protein structure.
c) The genetic code is expressed as three-nucleotide long sequences called codons.
d) The genetic code allows 20 amino acid to be coded by only 4 different nucleotides.
679
rRNA is short for _____ RNA.
ribosomal
680
A three-base sequence of mRNA is called a(n) ____
codon
681
A polypeptide is made of 31 amino acids. What is the minimum number of DNA nucleotides needed to code for this number of amino acids?
93 base pairs
682
Transcription is the process of copying genetic instructions from a molecule of _____ to mRNA.
DNA
683
Which of the following statements about codons are true?
The genetic code is expressed as a sequence of codons.
A codon is a three-base sequence of mRNA.
Every codon codes for an amino acid.
A codon is a three-base sequence of tRNA.
The genetic code is expressed as a sequence of codons.
| A codon is a three-base sequence of mRNA.
684
Which term refers to a sequence of three DNA nucleotides that codes for one amino acid?
a) codon
b) base triplet
b) base triplet
685
```
The enzyme RNA polymerase participates in which of the following processes?
Transcription
Replication
Protein folding
Alternative splicing
Translation
```
Transcription
686
```
Where does transcription take place?
In the Golgi apparatus
On ribosomes
In the nucleus
In mitochondria
```
In the nucleus
687
The process of reading an mRNA molecule and synthesizing the protein encoded in its nucleotide sequence is known as _______
translation
688
A three-base sequence of mRNA is called a(n) ______
codon
689
What is the role of mRNA in protein synthesis?
a) It opens the DNA helix and reads the bases from one strand of DNA.
b) It stays within the nucleus and serves as the template for transcription.
c) It binds free amino acids and delivers them to the ribosome to be added to a growing protein chain.
d) It carries the genetic code from the nucleus to the cytoplasm.
d) It carries the genetic code from the nucleus to the cytoplasm.
690
```
Which enzyme is responsible for transcribing DNA?
DNA polymerase
DNA ligase
RNA polymerase
Helicase
```
RNA polymerase
691
Transcription is the process of copying genetic instructions from a molecule of
_____ to mRNA.
DNA
692
At one end of each tRNA there is a sequence of three nucleotides known as the ______. This sequence is complementary to the bases on mRNA.
anticodon
693
```
Which term refers to the conversion of nucleotide sequences into amino acid sequences?
Replication
Filtration
Translation
Transcription
```
Translation
694
```
Which molecule carries the genetic code from the nucleus to the cytoplasm?
tRNA
DNA
rRNA
mRNA
```
mRNA
695
A base _____ is a consecutive sequence of three DNA nucleotides that codes for one amino acid.
triplet
696
Translation occurs in three steps. List these steps in chronological order.
Initiation
Elongation
Termination
697
The cluster of several ribosomes reading one mRNA during translation is called a _____
polyribosome
698
```
Which of the following refers to a 3-base sequence found in tRNA?
mRNA
Anticodon
Codon
Amino Acid
```
Anticodon
699
```
Golgi vesicles containing proteins to be released from the cell will become which type of vesicle?
Lysosome
Secretory
Endocytic
Peroxisome
```
Secretory
700
The process by which a cell makes a copy of its DNA so it can give complete and identical copies of all of its genes to each daughter cell its DNA is called _______
replication
701
One mRNA can have several ribosomes attached to it at one time during translation of mRNA. What term refers to this cluster of ribosomes?
Polyribosome
702
```
When synthesized proteins are to be exported out of the cells, they are packaged into secretory vesicles that originate in what organelle?
Smooth endoplasmic reticulum
Golgi complex
Ribosomes
Nucleus
```
Golgi complex
703
Where does translation take place?
On the ribosome
704
```
Which enzyme is responsible for unwinding DNA during DNA replication?
Ligase
Transferase
Helicase
Polymerase
```
Helicase
705
```
Which enzyme joins the newly synthesized DNA segments during DNA replication?
Transcriptase
Polymerase
Ligase
Helicase
```
Ligase
706
List the phases of the cell cycle in the correct order starting with G1.
G1
S
G2
M
707
The law of complementary base pairing states that a cell can do which of the following?
a) Reproduce one strand of DNA based on information in the other
b) Increase the number of amino acids in a protein
c) Align pairs of chromosomes at the equator of the cell during metaphase
d) Regenerate ATP from ADP
a) Reproduce one strand of DNA based on information in the other
708
```
Name the period of synthesis during which a cell makes a duplicate copy of its centrioles and all of its nuclear DNA.
M phase
Telophase
S phase
G1 phase
```
S phase
709
Name the correct order of the phases of mitosis from beginning to end.
Prophase, metaphase, anaphase, telophase
710
During DNA replication, the new short segments of DNA in one of the strands are joined together by the enzyme DNA _____
ligase
711
During the mitotic phase called ______, chromosomes condense, the nuclear envelope disappears, spindle fibers grow, and centrioles migrate to the poles of cell.
prophase
712
During the cell cycle, the stages G1, S, and G2 make up what phase?
Interphase
713
During metaphase, the spindle fibers form a lemon-shaped array called the _____ spindle.
mitotic
714
Which of the following occurs during anaphase?
A) Chromosomes align along the center or equator of the cell.
B) Centrioles migrate to the poles of cell.
C) Chromosomes are gathered at the poles of the cell.
D) Daughter chromosomes migrate to opposite ends of the cell.
D) Daughter chromosomes migrate to opposite ends of the cell.
715
Indicate which of the following events occur during prophase of mitosis. Select all that apply.
A) Chromosomes condense.
B) Centrioles are pushed apart.
C) Chromosomes migrate to opposite poles.
D) Nuclear envelope disappears.
E) Spindle fibers grow from the centrioles
A) Chromosomes condense.
B) Centrioles are pushed apart.
D)Nuclear envelope disappears.
E) Spindle fibers grow from the centrioles.
716
The new nuclear envelopes forms, new nucleoli appear, and the mitotic spindle vanishes during which phase of mitosis?
Telophase
717
The division of the cytoplasm to form two cells is called ______
cytokinesis
718
The chromosomes are seen as fully aligned on the cell equator during which phase of mitosis?
Metaphase
719
Daughter chromosomes migrate to opposite poles of the cell during which phase of mitosis?
Anaphase
720
Select that statements that describe telophase.
A) Chromosomes align along the center of the cell.
B) Chromatids cluster on each side of the cell.
C) A nuclear envelope reappears.
D) DNA is replicated.
E) Centrioles migrate to the poles of cell.
B) Chromatids cluster on each side of the cell.
| C) A nuclear envelope reappears.
