Exam 2 Review Flashcards
1
Q
What is a gene?
A
a locus (region) of DNA that encodes a functional RNA or protein product, it is also the molecular unit for heredity
2
Q
What is the molecular unit for heredity?
A
a gene (the smallest unit of measurement)
3
Q
What is a polypeptide?
A
a chain of amino acids, proteins are made up of one or more polypeptide molecules
4
Q
Amino acids are linked _____ in _____ bonds in order to form a polypeptide.
A
covalently, peptide
5
Q
What are the subunits of proteins?
A
amino acids
6
Q
What are the 5 main functions of nucleic acids?
A
heredity (store and transport information), cell control, energy storage, electron carriers, and signaling (i.e. DNA and RNA)
7
Q
What is the central dogma of molecular biology?
A
DNA can be copied into DNA (replication). DNA codes for RNA, which codes for proteins. DNA is responsible for heredity (passing of traits onto offspring). It contains the instructions for building RNA and proteins, which make up the structure of the body and carry out most of its functions.
8
Q
What is the coding of DNA to RNA called?
A
transcription
9
Q
What is the coding of RNA to a protein called?
A
translation
10
Q
What is the process of DNA creating more DNA?
A
DNA replication
11
Q
What is a macromolecule?
A
a series of small subunits covalently bonded to form a larger molecule
12
Q
What is a monomer?
A
one subunit (relatively small molecule)
13
Q
What is a dimer?
A
two subunits
14
Q
What is a trimer?
A
three subunits
15
Q
What is a tetramer?
A
four subunits
16
Q
What are the subunits of lipids?
A
fatty acids and glycerol
17
Q
What are the subunits of carbohydrates?
A
monosaccharides
18
Q
What are the subunits of nucleic acids?
A
nucleotides
19
Q
What are isomers? Give an example.
A
molecules that have the same chemical formula, but a different arrangement of atoms in space (fructose and glucose)
20
Q
Plants store energy as _____ while animals store energy as _____.
A
starch, glycogen
21
Q
What is a disaccharide?
A
a sugar composed of two monosaccharides
22
Q
What are the three types of lipids?
A
triglycerides, phospholipids, and steroids
23
Q
What is polymerization?
A
a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks
24
Q
Subunits of a macromolecule are joined together in _____ bonds.
A
covalent
25
What type of reaction is responsible for the polymerization of the four main types of subunits/molecules?
a condensation reaction (a reaction accompanied with the formation of a water molecule, water is lost), also known as a "dehydration reaction"
26
What type of covalent bond do amino acids form?
peptide
27
What type of covalent bond do fatty acids and glycerol form?
ester
28
What type of covalent bond do monosaccharides form?
glycosidic
29
What type of covalent bond do nucleotides form?
phosphodiester
30
Are lipids hydrophobic or hydrophilic?
hydrophobic (not soluble in water)
31
What are triglycerides responsible for?
energy storage
32
What are phospholipids responsible for?
membranes
33
What are steroids responsible for?
signaling (hormones) and membranes
34
What are triglycerides responsible for?
energy storage
35
What are the components of a triglyceride?
one glycerol and three fatty acids
36
Within a triglyceride, each carbon atom will form exactly _____ bonds with other atoms.
four
37
What is a glycerol molecule?
three carbons and three hydroxyl (OH-) groups
38
What is a fatty acid?
chain of carbons (CH2) with carboxyl (COOH-) at one end, and CH3 on the other
39
What is a carboxyl group?
COOH-
40
How many carbons exist between the carboxyl and CH3 in a fatty acid?
10-40
41
Fatty acids are amphipathic, which means _____.
the two ends of the molecule differ in chemical properties
42
The hydrophilic part of a fatty acid consists of the _____ group, which means that this part of the molecule is _____.
carboxyl, polar (because water is polar, too)
43
The hydrophobic part of a fatty acid consists of a _____ chain and a _____ molecule, which means that this part of the molecule is _____.
carbon/hydrogen chain, CH3, nonpolar (because water is polar)
44
What does "saturated" mean when it comes to fatty acids?
hydrogen occupies all available bond space
45
What does "unsaturated" mean when it comes to fatty acids?
hydrogen does not occupy all available bond space
46
What forms if two adjacent carbons are missing hydrogen atoms within a fatty acid?
a double bond
47
Saturated fats are "regular," so they form _____.
tight crystals
48
Saturated fats have _____ melting points.
high
49
Unsaturated fats have _____ melting points.
low
50
What is a fatty acid "tail"?
string of carbons
51
Saturated fates have _____ bonded carbons because all of the bond space is occupied with hydrogen.
single
52
Unsaturated fats have _____ or _____ bonded carbons because not all of the bond space is occupied with hydrogen.
double, triple
53
Unsaturated fatty acids are usually in _____ form and have _____ tails.
liquid, short
54
Saturated fatty acids are usually in _____ form and have _____ tails.
solid, long
55
Amphipathic lipids form _____ in water.
micelles
56
What is a micelle?
a lipid molecule that arranges itself in a spherical form in an aqueous solution
57
An amphipathic lipid has a _____ head and a _____ tail.
hydrophilic, hydrophobic
58
What is the function of a phospholipid?
membranes
59
What happens when two hydroxyl groups meet of fatty acids?
The fatty acids bond, sharing the oxygen of one OH-, while the other becomes part of the water molecule that is lost.
60
What does a phospholipid consist of?
two fatty acid tails attached to the glycerol molecule, one phosphate (PO43-), and an R group
61
What does the "R" in "R group" stand for?
residue (as in an undefined molecular group, such as H, OH, CH3, etc.)
62
A phospholipid is has a _____ head and two _____ tails, which means that it is amphipathic.
hydrophilic, hydrophobic
63
Micelles _____ when they come into contact.
fuse
64
The fusing of micelles is a _____ process.
spontaneous
65
What is solubility of lipids in water determined by?
length of chains (tails), and saturation
66
Membranes in cells consist of _____ layers of phospholipids. This is called a singular _____ membrane. Understand this structure.
two, bilayer (hydrophilic heads face outward and inward toward the cell, and the hydrophobic tails face each other)
67
A double membrane consists of how many bilayers and how many phospholipid layers?
two, four
68
What is the "fluid mosaic model"?
the idea that membranes are fluid (with other components), to form a patchwork pattern of phospholipids with IMP's and PMP's scattered about
69
What is an integral membrane protein (IMP)?
a protein that spans the width of the membrane
70
What is a peripheral membrane protein (PMP)?
a protein that is embedded in the membrane but not all the way through
71
Name three functions of proteins.
channels (IMP), enzymes, and carriers
72
Membranes are fluid, so if they are pressed together, they will _____.
fuse
73
Name four things that will enhance the fluidity of a membrane.
warm temperatures, cholesterol, shorter fatty acid tails on the phospholipids, less saturation
74
Organic compounds always contain _____.
carbon
75
Micelles are specifically _____ molecules.
lipid
76
What are two of the functions of steroids?
increased membrane fluidity, hormones
77
What is the structure of a steroid?
ring structure, one carbon at every point of ring, other molecules also attached
78
What, specifically, is a hormone?
a steroid- signaling molecule that is derived from cholesterol
79
Is "equilibrium" synonymous to "equal distribution"?
no
80
How can you increase the rate of diffusion?
by adding energy
81
What does "turgid" mean?
swollen
82
Active transport requires _____.
energy (in the form of ATP)
83
What are the two major functions of macromolecules?
cytoskeleton (structural) and enzymes (functional)
84
What are the main three functions of enzymes?
catalysts, controls whether a reaction occurs, controls reaction speed
85
What are four important types of carbohydrates?
sugar, starch, glycogen, and cellulose
86
What are all membranes made out of?
lipids and proteins
87
More saturation results in _____ fluidity.
less
88
What are the two types of facilitated diffusion?
channel-mediated and carrier-mediated
89
What is simple diffusion?
random molecular movement so that eventually molecules become evenly distributed
90
What effect does energy have on simple diffusion?
it speeds up the process
91
Dialysis tubing is an example of a _____ or _____ permeable membrane.
selectively, differentially
92
What does tonicity mean?
concentration
93
What is plasmolysis?
the process of a cell using water in a hypertonic solution
94
The _____ is responsible for carrier-mediated diffusion.
peripheral membrane protein (PMP)
95
What is endocytosis? What effect does this have on the cell membrane?
movement into a cell, decreases the amount of cell membrane (vesicle used inside cell)
96
What is exocytosis? What effect does this have on the cell membrane?
movement out of a cell, increases the amount of cell membrane (vesicle that was used inside of cell becomes part of the membrane)
97
A _____ describes repeatedly dividing a cell.
clock
98
What is the clockwise "order" of components of the cell cycle clock, starting in the upper righthand corner?
G1 - S - G2 - M
99
What happens in G1?
this is "gap one," when the cell grows
100
What happens in S?
synthesis (DNA synthesis/replication)
101
What happens in G2?
this is "gap two," when the cell prepares for division
102
How can you describe, specifically, S (synthesis)?
single chromosome becomes double (they are both "one" chromosome, but with twice as much "stuff" after replication) -- 00 is one chromosome with one chromatid (monosome), 88 is one chromosome with 2 chromatids (disome)
103
What is the M phase on the cell cycle clock?
mitosis/meiosis
104
What is meiosis?
sexual reproduction, one nucleus becomes four, introduces variability (nuclei are not identical)
105
What is mitosis?
vegetative, somatic, asexual
responsible for growth, cell replacement, wound repair, hair and nail growth
results in two nuclei that are clones
106
What is cytokinesis?
the division of cell cytoplasm (may or may not occur after both meiosis and mitosis), the nuclei coexist in the cytoplasm until this occurs
107
What is G0?
Where cells go to no longer divide (outside of G1). They can pretty much enter and leave this state as they please.
108
The cell will divide if _____.
it passes the point of no return (a point on G2)
109
What is a "checkpoint" of cell division?
self-assessments to make sure the cell should divide (not going through the G2 checkpoint could result in cancer, where cell division is out of control)
110
What is a chromosome defined as?
one DNA molecule with its associated histone proteins (proteins that provide a "framework" for DNA to wrap around like a scarf)
111
How many types of histones are there?
five
112
What is an "interphase chromosome"?
one that is not wrapped or coiled tightly, it is invisible and called "chromatin," essentially an invisible blob
113
What happens to chromosomes during the "M phase"?
The chromosomes condense, making it easier for them to separate (rather than a glob, it's little 88 things)
114
What are the four main stages of mitosis, in order?
1. prophase
2. metaphase
3. anaphase
4. telophase
(PMAT?)
115
Describe what happens in the prophase of mitosis.
the centriole divides and migrates to the poles, the chromosomes condense, the nuclear envelope "disappears," and the spindle forms (microtubules (MTOC) and centrioles)
116
Describe what happens in the metaphase of mitosis.
chromosomes align at the equatorial plane and attach to the spindle
117
Describe what happens in the anaphase of mitosis.
the two halves of the chromosome separate, pulled by the spindle to opposite poles of the cell
118
Describe what happens in the telophase of mitosis.
the chromosomes have reached the poles of the cells, the nuclear envelope reforms, chromosomes decondense, the product is one cell with two nuclei (time for cytokinesis!)
119
How does cytokinesis work in bacteria?
no "M" phase because there is no nucleus, division in a process called "fission"
120
How does cytokinesis work in animal cells?
Furrowing- microtubules reorganize and pinch the cell in two
121
How does cytokinesis work in plants?
"phragmoplast" found in plants is used
122
What is the general structure of DNA?
DNA is a polymer of nucleotides, large subunits linked by covalent bonds (that are formed in the condensation/dehydration reaction)
123
What is the structure of a nucleotide?
sugar, phosphate, base
124
What does the sugar look like within a nucleotide?
5 carbons, ribose, deoxyribose (if it lost an oxygen)
125
Where is the phosphate molecule located within a nucleotide?
at carbon #5 (one of three phosphates is attached here)
126
What are the five possible bases of a nucleotide?
adenine, thymine, cytosine, guanisine, uracil (RNA only)
127
Where does the base attach within a nucleotide?
carbon number one
128
How are the carbons within a nucleotide ordered?
1-5 starting at the right upper corner and going clockwise
129
What is ATP as far as nucleotides go?
a nucleotide triphosphate
130
Which bases are pyrimidines?
cytosine, thymine, uracil
131
Which bases are purines?
adenine, guanisine
132
How does the polymerization of nucleotides work?
polymerization=chain building, from the 5' (front/phosphate) to 3' (tail) end
133
What is the result of the polymerization of nucleotides?
a DNA (sugar-phosphate) backbone
134
DNA is _____ stranded.
double
135
What type of bond holds the two DNA strands together?
hydrogen bonds
136
What stage of the cell cycle does DNA coil?
M phase
137
How many hydrogen bonds does the base pair A=T have?
two
138
How many hydrogen bonds does the base pair C=G have?
three
139
What does "denature" mean?
melt
140
How does DNA replication work?
occurs during the interphase (S phase), each half of the original DNA makes a copy, so each new DNA set has an old and new strand
