Unit 1 Flashcards
1
Q
6 levels of structural organization
A
- Chemical
- Cellular
- Tissue
- Organ
- System
- Organismal
2
Q
What is the Chemical Level of organization
A
Atoms (the smallest units of matter) and molecules (2+ atoms joined together)
3
Q
What is the Cellular Level of organization
A
Molecules combine to form cells (the basic structural and functional units of an organism that are composed of chemicals)
4
Q
What is the Tissue Level of organization
A
Groups of cells and the materials surrounding them that perform a particular fxn
5
Q
What is the Organ Level of organization
A
Composed of 2+ different types of tissues and have specific fxns and typically recognizable shapes
6
Q
What is the System Level of organization
A
Consists of related organs with a common fxn
7
Q
What is the Organismal Level of organization
A
All the parts of the human body functioning together
8
Q
4 types of tissue
A
- Epithelial
- Connective
- Muscular
- Nervous
9
Q
6 basic life processes
A
- Metabolism = catabolism & anabolism
- Responsiveness = body’s ability to detect and respond to changes
- Movement
- Growth = increase in body size that results from an increase in the size of existing cells, an increase in the # of cells or both
- Differentiation = the development of a cell from an unspecialized to specialized state
- Reproduction = formation of new cells OR production of new individual
10
Q
Catabolism
A
Breakdown of complex chemical substances into simpler components
11
Q
Anabolism
A
Building of complex chemical substances from smaller, simpler components
12
Q
Homeostasis
A
A dynamic condition; the maintenance of relatively stable conditions in the body’s internal environment
13
Q
Body fluids
A
Dilute, watery solutions containing dissolved chemicals that are found inside cells and surrounding them
14
Q
2 types of fluid
A
- ICF (within cells)
- ECF (surrounds cells)
15
Q
Interstitial fluid
A
ECF that fills the narrow spaces between the cells of tissues (e.g., blood plasma, lymph, synovial fluid)
16
Q
How the cardiovascular system contributes to homeostasis
A
Transports O2 and nutrients through the body:
- O2 and nutrients diffuse into interstitial fluid via blood capillaries
- O2 and nutrients are taken up by cells and metabolized for energy
- During metabolization, cells produce waste which enter interstitial fluid and move across blood capillary walls into plasma
- Cardiovascular system transports waste to the appropriate organ for elimination to the external environment
17
Q
2 regulatory systems to control homeostasis
A
- Nervous system
- Endocrine system
18
Q
What does the nervous system do
A
Sends electrical signals (nerve impulses or action potentials) to organs that counteract (quick change)
19
Q
What does the endocrine system do
A
Glands secrete messenger molecules called hormones into the blood (slow change)
20
Q
Feedback systems (loops)
A
A cycle of events in which the status of a body condition is monitored, evaluated, changed, monitored, reevaluated, etc.
21
Q
3 basic components of feedback systems
A
- Receptor
- Control center
- Effector
22
Q
Receptor (afferent pathway)
A
body structure that monitors changes in a controlled condition and sends inputs to a control center
23
Q
Control center (efferent pathway)
A
Sets the narrow range within which a controlled condition should be maintained, evaluates the input it receives from receptors, and generates output commands when they are needed
24
Q
Effector
A
Body structure that receive outputs from the control center and produces a response or effect that changes the controlled condition
25
Negative feedback
Reverses a change in a controlled condition (regulate conditions that remain stable over long periods, e.g., blood pressure)
26
Positive feedback
Strengthens or reinforces a change in one of the body's controlled conditions (reinforce conditions that don't happen often, e.g., childbirth)
27
Anatomical position
Standard position of reference for regions of the body
28
Prone position
Lying face down
29
Supine position
Lying face up
30
6 principal regions of the body
1. Head
2. Neck
3. Trunk
4. Upper limbs
5. Lower limbs
6. Groin
31
Head (region)
Skull + Face
32
Trunk (region)
Chest, abdomen, pelvis
33
Upper limbs (region)
Attached to the trunk and includes the shoulder, armpit, arm (shoulder to elbow), forearm (elbow to wrist), wrist and hand
34
Lower limb (region)
Attached to the trunk and includes the buttock, thigh (buttock to knee), leg (knee to ankle), ankle and foot
35
Directional terms
Words that describe the position of one body part relative to another; most can be grouped into pairs that have opposite meanings
36
Superior
Towards the head or the upper part of a structure
37
Inferior
Away from the head, or the lower part of a structure
38
Anterior
Nearer to or at the front of the body
39
Posterior
Nearer to or at the back of the body
40
Medial
Nearer to the midline
41
Lateral
Farther from the midline
42
Intermediate
Btw 2 structures
43
Ipsilateral
On the same side of the body as another structure
44
Contralateral
On the opposite side of the body as another structure
45
Proximal
Nearer to the attachment of a limb to the trunk
46
Distal
Farther from the attachment of a limb to the trunk
47
Superficial
Toward or on the surface of the body
48
Deep
Away from the surface of the body
49
Planes
Imaginary flat surfaces that pass through body parts
50
Sagittal plane
Vertical plane that divides the body / organ into right and left sides:
1. Midsagittal plane (through the midline)
2. Parasagittal plane (not through the midline)
51
Frontal plane
Divides the body / organ into anterior and posterior portions
52
Transverse plane
Divides the body / organ into anterior and posterior portions
53
Oblique plane
Passes through the body / organ at on oblique angle
54
Sections
A cut of the body / organ made along one of the planes
55
Body cavities (4 overarching)
Spaces that enclose internal organs which are separated by bones, muscles and ligaments
1. cranial
2. vertebral
3. Thoracic
4. Abdominopelvic
56
Cranial cavity
A hallow space of the head composed of the cranial bones
57
Vertebral canal
Bones of the vertebral column (backbone)
58
Thoracic cavity (3 zones)
Formed by the ribs, muscles of the chest, sternum and thoracic portion of the vertebral column
1. pericardial cavity (x1) = around the heart
2. pleural cavities (x2) = around the lungs
3. mediastinum = btw the lungs
59
Abdominopelvic cavity (2 cavities)
From the diaphragm to the groin, encircled by the abdominal muscular wall and bones/muscles of the pelvis
1. Abdominal cavity
2. Pelvic cavity
60
Abdominal cavity
Contains: stomach, spleen, liver, gallbladder, small intestine, most of large intestine
61
Pelvic cavity
Contains: urinary bladder, some large intestine, organs of reproductive system
62
Membrane
A thin, pliable tissue that covers, lines, partitions or connects structures
63
Serous membrane
A double-layered membrane that covers the viscera within the thoracic and abdominal cavities and lines the walls of the thorax and abdomen and includes 2 parts:
1. Parietal layer
2. Visceral layer
64
Membrane of the thoracic cavity
2 serous membrane membranes:
1. Pleura = membranes of the pleural cavities
2. Pericardium = membrane of the pericardial cavity
65
Membrane of the abdominal cavity
1x serous membrane:
1. Peritoneum
66
3 components of non-living things
1. Matter
2. Mass
3. Weight
67
Matter
Anything that occupies space and has mass
68
Mass
The amount of matter in any object
69
Weight
The force of gravity acting on matter
70
4 major chemical elements of the body
1. Oxygen
2. Carbon
3. Hydrogen
4. Nitrogen
71
8 lesser elements of the body
1. Calcium
2. Phosphorus (P)
3. Potassium (K)
4. Sulfur (S)
5. Sodium (Na)
6. Chlorine (Cl)
7. Magnesium (Mg)
8. Iron (Fe)
72
Atoms
Make up elements and are the smallest units of matter
73
Subatomic particles (3 types)
Make up atoms:
1. Protons
2. Neutrons
3. Electrons
74
Atomic number
The # of protons in the nucleus of an atom
75
Mass number
The sum of an atoms protons and neutrons
76
Isotopes
Atoms of an element that have different #'s of neutrons and therefore different mass numbers
77
Ions
An atom that has a positive or negative charge b/c it has unequal #'s of protons and electrons (e.g., Ca2+)
78
Molecule
When 2 or more atoms share electrons (e.g., O2, H2O)
79
Compound
A substance containing atoms of 2+ different elements (e.g., H2O, NaCl)
80
Chemical bonds (3 types)
Forces that hold together the atoms of a molecule or compound, form when valence shell is chemically unstable
1. Ionic
2. Covalent
3. Hydrogen
81
Ionic bonds
The force of attraction that holds together ions with opp. charges resulting in a gain or loss of electrons (e.g., NaCl)
82
Covalent bonds
When 2+ share electrons rather than gaining or losing them
Types:
1. Non-polar = electrons shared equally (e.g., CH4)
2. Polar = electrons shared unequally (e.g., H2O)
83
Hydrogen bonds
Result from attraction of opp. charged parts of molecules (weakest type)
84
Surface tension
A measure of the difficulty of stretching or breaking the surface of a liquid
85
Cohesion
The tendency of like particles to stay together (hydrogen bonds that link water molecules)
86
3 types of energy
1. Potential = energy stored in matter
2. Chemical = energy stored in chemical bonds
3. Kinetic = energy of motion
87
Low of conservation of energy
The total amount of energy present at the beginning and end of a chemical rxn is the same. Although energy cannot be created or destroyed, it may be converted from one form to another
88
Catalysts
Chemical compounds that speed up chemical reactions by lowering the activation energy needed for a rxn to occur (e.g., enzymes)
89
5 types of chemical rxns
1. Synthesis (anabolism)
2. Decomposition (catabolism)
3. Exchange
4. Reversible
5. Redox (transfer of electrons btw atoms/molecules)
90
Inorganic compounds
Usually lack carbon + structurally simple (e.g., CO2, HCO3-, H2O)
91
Organic compounds
Always contain carbon, always have covalent bonds
92
Water
The most important abundant inorganic, polar compound in all living systems:
- Solvent (dissolves other substances)
- High heat capacity / heat of vaporization (requires a lot of heat to change state)
- Lubricant
93
Hydrophilic
Water loving (polar)
94
Hydrophobic
Water fearing (non-polar)
95
Chemical rxns involving water (2 types)
1. Hydrolysis = decomposition rxn involving water and breaks large molecules into smaller molecules
2. Dehydration synthesis = when two smaller molecules join to form larger molecule(s) and water
96
3 types of liquid mixtures
1. Solution = small solute particles (transparent)
2. Colloid = large solute particles (opaque)
3. Suspension = contains solute particles that settle out + accumulate
97
Buffer systems
Fxn to convert strong acids/bases in body fluids into weak acids/bases (weak acids/bases do not ionize easily) by adding / removing H+ and OH-
98
5 types of organic compounds
1. Carbs
2. Lipids
3. Proteins
4. Nucleic acids
5. ATP
99
Macromolecule
Small organic molecules that combine into large ones (e.g., carbs, lipids, proteins, nucleic acids)
100
Polymers
A large molecule formed by the covalent bonding of many identical or similar small building block molecules called monomers
101
Carbohydrates (organic molecule 1)
Fxn = source of chemical energy to make ATP
Key elements = C, H, O
3 groups:
1. Monosaccharides (atoms)
2. Disaccharides (2 mono. joined via dehydration synthesis)
3. Polysaccharides (3+ mono. joined via dehydration synthesis)
e.g., sugar, glycogen, starch, cellulose
102
Monosaccharide
Simple sugar composed of atoms; soluble in water
103
Disaccharides
Simple sugar composed of 2 mono. via dehydration synthesis; soluble in water
104
Polysaccharides
Composed of 3+ mono. via dehydration synthesis; insoluble in water; e.g., starch, cellulose
105
Lipids (organic molecule 2)
Key elements = C, H, O
Groups:
1. Fatty acids
2. Triglycerids
3. Phospholipids
4. Steriods
5. Eicosanoids
6. Fat-soluble vitamins
7. Lipoproteins
106
Fatty acids
Simplest lipid
Used to synthesize triglycerides and phospholipids or catabolized to generate ATP
2 types:
1. Saturated (completely saturated with H)
2. Unsaturated (not completely saturated with H)
107
Triglycerides
Most plentiful lipid in the body + most highly concentrated form of chemical energy
Solid = saturated fat
Liquid = oil (monounsaturated or polysaturated)
108
Phospholipids
Amphipathic (have polar and non-polar parts)
e.g., make up the plasma membrane of cells
109
Steriods
4 rings of carbon atoms
E.g.,
- Cholesterol = cell membrane structure
- Estrogen/testosterone,
- Cortisol = blood sugar
- Bile salts = lipid digestion
- Vitamin D = bone growth
110
Eicosanoids
Lipids derived from 20-carbon fatty acids
111
Lipoproteins
A lipid-protein complex to help lipids become more soluble in blood plasma
112
Proteins (organic molecule 3)
Large, complex molecules created from amino acids and polypeptides (chains of amino acids)
Key elements: C, H, O, N
Fxns:
- Catalytic: speed up rxns
- Structural: tissue, collagen, hair, skin
- Contractile: drive muscle contraction
- Immunological: acts as antibodies
- Transport: carry substances throughout body
- Regulatory: fun as hormones
113
Denaturation
When a protein unravels and becomes non-functional
114
Amino acids
Monomers (building blocks) of proteins, of which there are 20 types
115
Enzymes
A protein molecule that acts as a catalysts in living cells (e.g., oxidases)
116
Nucleic acids (organic molecule 4)
Huge organic compounds
Key elements = C, H, O, N, P
2 types:
1. Deoxyribonucleic acid (DNA)
2. Ribonucleic acid (RNA)
117
DNA
Fxn: Encodes info to make proteins
Structure: Double stranded, A -> T, G -> C
Copying: Self-replicating
118
RNA
Fxn: Carries the genetic code and helps make proteins
Structure: Single stranded, A -> U, G -> C
Copying: Made from DNA blueprint
119
ATP (organic molecule 5)
Fxn: Energy of living systems in exergonic catabolic rxns
ATP+H2O->ADP+P+energy
ADP+P+energy->ATP+H2O
120
Cells (3 main parts)
The basic, living, structural and functional units of the body
1. Plasma membrane
2. Cytoplasm
3. Nucleus
121
Plasma membrane
The cell's flexible outer surface, separating the cell's internal and external environments (selective barrier + communicator)
122
Cytoplasm
All cellular contents between the plasma membrane and the nucleus made of 2 key components:
1. Cytosol = intracellular fluid (ICF)
2. Organelles
123
Nucleus
Organelle that houses most of a cell's DNA
124
Fluid mosaic model
Describes the plasma membrane as a continually moving sea of fluid lipids that contain a mosaic of proteins
125
3 types of lipid molecules in the plasma membrane
1. Phospholipids = 75%
2. Cholesterol = 20%
3. Glycolipids = 5%
126
Phospholipids
Amphipathic molecules with a polar (hydrophilic) head and 2 non-polar (hydrophobic) tails
127
4 membrane proteins
1. Integral proteins
2. Transmembrane proteins
3. Peripheral proteins
4. Glycocalyx
128
Integral Membrane Proteins
Extend into or through the lipid bilayer and firmly embedded in it (amphipathic)
129
Transmembrane proteins
Span the entire lipid bilayer and protrude into both the cytosol and extracellular fluid
130
Peripheral proteins
Not firmly embedded in the membrane + support the plasma membrane, anchor integral proteins and participate in moving materials / organelles within cells
131
Glycocalyx membrane proteins
A sugary coat made of the carbohydrate group of glycolipids and glycoproteins; varies from cell to cell and therefore acts as the molecular "signature" of cells for recognition
132
6 functions of membrane proteins
1. Ion channels
2. Carrier (transporters)
3. Receptors
4. Enzymes
5. Linkers
6. Cell-identity markers
133
What is meant by membrane fluidity
Membrane lipids and proteins easily rotate and move sideways in their half of the bilayer
Fluidity increases with double bonds & higher temperatures
134
Membrane selective permeability
The plasma membrane permits some substances to pass more readily than others b/c of the non-polar hydrophobic interior
The lipid biyler of the plasma membrane is:
- highly permeable to non-polar molecules (O2, CO2)
- Moderately permeable to polar, uncharged molecules (H2O)
- Impermeable to ions and large, uncharged polar molecules (glucose)
135
Transmembrane proteins
Act as channels and carriers to increase the plasma membrane's permeability to ions and uncharged polar molecules that, unlike H2O and urea, cannot cross the lipid bilayer unassisted
136
Plasma membrane electrical gradient
The inner surface of the plasma membrane is MORE negatively charged and the outer surface is MORE positively charged
137
Plasma membrane concentration gradient
A difference in the concentration of a chemical, such as inside and outside the plasma membrane
138
Electrochemical gradient of the plasma membrane
Combines influence of the concentration gradient and the electrical gradient to help move substances across the plasma membrane
139
3 types of membrane transport
1. Passive
2. Active
3. Vesciles
140
Passive membrane transport
Substances move down their concentration / electrical gradient to cross the membrane via diffusion, using only its own kinetic energy from particles that are moving
3 types:
1. Simple diffusion
2. Facilitated diffusion
3. Osmosis
141
What is simple diffusion
A passive process in which substances move freely through the lipid bilayer of the plasma membranes of cells without the help of membrane transport proteins
Substances transported:
- Nonpolar molecules: O2, CO2, fatty acids, steriods, fat-soluble vitamins
- Polar molecules: H2O, urea, alcohol
142
What is facilitated diffusion
A passive process in which polar/highly charged substances move through the lipid bilayer via one of two integral membrane proteins:
1. Channel-mediated facilitated diffusion
2. Carrier-mediated facilitated diffusion
143
Channel-mediated facilitated diffusion
A solute moves down its concentration gradient across the lipid bilayer through a membrane channel (e.g., K+ and Cl- or Na+ and Ca2+) at certain sites
Gated channels = when part of the channel protein acts as a plug, changing shape in one way to open the pore and in another way to close it
144
Carrier-mediated facilitated diffusion
A passive process in which a carrier (or transporter) moves a solute down its concentration gradient across the plasma membrane (e.g., glucose, fructose, vitamins)
145
What are the 3 steps of transporting glucose across the plasma membrane
Occurs via carrier-mediated facilitated diffusion
1. glucose binds to a specific type of carrier protein (glucose transporter - GluT) on the outside surface of the membrane
2. transporter undergoes a change in shape, glucose passes through the membrane
3. transporter releases glucose on the other side of the membrane
146
Transport maximum
An upper limit on the number of carrier available in the plasma membrane to participate in carrier-mediated facilitated diffusion
Once all carrier are occupied the transport maximum is reached aka is fully saturated
147
What is osmosis
A passive process by which water moves through a selectively permeable membrane from an area of lower solute concentration (i.e., higher water concentration) to an area of higher solute concentration (i.e., lower water concentration) via one of 2 methods:
1. Via simple diffusion
2. Via water channels + aquaporin integral membrane proteins
148
What are the 3 types of solutions created via osmosis
1. Isotonic = any solution in which a cell maintains its normal shape and volume
2. Hypotonic (grow) = a solution that has a lower concentration of solutes
3. Hypertonic (shrink) = has a higher concentration of solutes
149
Tonicity
A measure of a solution's ability to change the volume of a cell by altering its water content
150
Lysis
The rupture of other types of cells due to placement in a hypotonic solution
151
Define active membrane transport and what are the 2 types
An active process requiring energy (usually ATP) to allow carrier proteins (transmembrane proteins) to move solutes across the plasma membrane against a concentration gradient / electrical gradient
2 types:
1. Primary active transport
2. Secondary active transport
Substances transported:
- Polar / charged solutes
152
What is primary active transport and what substances does it transport
Energy derived from hydrolysis of ATP changes the shape of a carrier protein, which “pumps” a substance across a plasma membrane against its con- concentration gradient
Substances transported:
- Na+, K+
- Ca2+, H+
- I-, Cl-
- Other ions
153
What are the 4 steps of the sodium potassium pump
Objective: maintain a low concentration of Na+ and a high concentration of K+ in the cytosol
1. 3 Na+ in cytosol bind to protein pump
2. Binding triggers hydrolysis of ATP into ADP + P which causes a change in shape, expelling 3 Na+ into ECF
3. 2 K+ bind and trigger release of P group from protein pump, triggers change in shape
4. Reverts to original shape and releases 2 K+ into the cytosol and the cycle repeats
154
What is secondary active transport and what substances does it transport
Coupled active transport of 2 substances across the plasma membrane using energy stored in a Na+ or H+ concentration gradient during primary active transport using anti ports and symports
1. Antiporter: move Na+ (or H+) and another substance in opposite directions across the membrane
2. Symporter: move Na+ (or H+ and another substance in the same direction across the membrane
Substances transported:
- Antiport: Ca2+, H+
- Symport: glucose, amino acids
155
What is membrane transport using vesicles (3 types)
An active process in which tiny spherical membrane sacs transport substance into or out of cells using ATP
1. Endocytosis: into the cell
2. Exocytosis: out of the cell
3. Transytosis: Both
156
What is endocytosis and what are the 3 sub-types
A transport vesicle used to move materials into a cell; includes 3 types:
1. Receptor-mediated
2. Phagocytosis
3. Bulk-phase (pinocytosis)
157
What is receptor-mediated endocytosis and what are the 6 steps
A selective process by which cells take up specific ligands (molecules that bind to specific receptors) trigger infolding of a clathrin-coated pit that forms a vesicle containing ligands
Transported substances (ligands):
- Cholesterol
- Transferrin
- Vitamins
- Antibodies
- Hormones
6 steps:
1. Binding: LDL particle binds to plasma membrane from the ECF
2. Vesicle formation: Vesicle forms from invagination of the plasma membrane and pinches off
3. Uncoating: Cathrin-coated vesicle loses its coat and become uncoated
4. Fusion: vesicle fuses with an endoscope and LDL particles separate from their receptors
5. Recycling of receptors: receptors become transport vesicles that return to the plasma membrane
6. Degradation in lysosomes: lysosomes containing digestive enzymes break down large protein/lipid molecules of the LDL into amino acids, fatty acids and cholesterol
158
What is phagocytosis endocytosis and how does it happen
"Cell eating” is a form of endocytosis in which the cell engulfs large solid particles into a cell after pseudopods engulf it to form a phagosome.
Examples:
1. Macrophages = in body tissues
2. Neutrophils = white blood cells
Transported substances:
- Bacteria
- Viruses
- Aged/dead cells
159
What is bulk-phase endocytosis and what substances does it transport
"Cell drinking"; movement of ECF into a cell by infolding of plasma membrane to form a vesicle (does not involve receptors)
Substances transported:
- Solutes in ECF
160
What is exocytosis and what substances does it transport
Movement of substances out of a cell in secretory vesicles that fuse with the plasma membrane and release their contents into the ECF
Substances transported:
- Neurotransmitters
- Hormones
- Digestive enzymes
161
What is transcytosis and what substances does it transport
Movement of a substance through a cell as a result of endocytosis on one side and exocytosis on the opposite side
Substances transported:
- Antibodies across endothelial cells
E.g., substances btw blood plasma and interstitial fluid
162
What is the cytoplasm of a cell and its 2 components
Consists of all the cellular contents between the plasma membrane and the nucleus
2 components:
1. Cytosol
2. Organelles
163
What is the cytosol (ICF) of a cell, its purpose and structure
The fluid portion of the cytoplasm that surrounds organelles and contains dissolves/suspended components (e.g., ions, glucose)
Purpose:
The site of many chemical rxns required for cell existence
Structure:
Cytoskeleton = a network of 3 types of protein filaments that extends throughout the cytosol
164
What are the 3 types of protein filaments that make up the cytoskeleton
1. Microfilaments
2. Intermediate filaments
3. Microtubules
165
What are microfilaments?
Thinnest protein filament of the cytoskeleton of a cell (aka cytosol) that:
1. generate movement
2. provide mechanical support to anchor cytoskeleton to integral proteins
166
What are intermediate filaments?
Thickest protein filament of the cytoskeleton of a cell (aka cytosol) that:
1. stabilize the position of organelles
2. Help attach cells to one another
167
What are microtubules?
Largest protein filament made of tubulin in the cytoskeleton of a cell (aka cytosol) that:
1. Help determine cell shape
2. help secretory vesicles move
3. include cilia and flagella
168
What are organelles?
Specialized structures within the cytosol of a cell that have characteristic shapes, and they perform specific functions in cellular growth, maintenance, and reproduction
169
What is a centrosome?
Microtubule organizing organelle of a cell, located near the nucleus
170
What are cilia?
Short, hairlike projections (organelles) that extend from the surface of the cell and coordinate movement of fluid along the surface of a cell (e.g., in cells of the respiratory tract)
171
What are flagella?
Long projections (organelles) that extend from the surface of a cell and move the cell (e.g., sperm cell tail)
172
What is the endoplasmic reticulum? What are its 2 forms?
A organelle that is a network of membranes in the form of flattened sacs or tubules
2 forms:
1. Rough ER = continuous with nuclear membrane + studded with ribosomes produces secretory proteins, membrane proteins and organellar proteins
2. Smooth ER = extends from the rough ER + no ribosomes synthesizes fatty acids and steroids (estrogen and testosterone)
173
What is the Golgi complex?
An organelle made of small flat membranous sacs called cisterns that accepts proteins / enzymes at the cis face / via transport vesicles from the rough ER and packages them into secretory, membrane or transport vesicles for delivery to their final destination via the trans face (exit)
174
What are lysosomes?
An membrane-enclosed vesicles (organelle) that forms from the Golgi complex and degrades proteins delivered to them in vesicles
Fxns:
- Digest molecules that enter the cell via endocytosis
- Recycle cell structures/organelles during autophagy (regeneration)
- Destroy an entire cell during autolysis
175
What are peroxisomes?
Organelles that contain oxidases, enzymes that can oxidize (remove hydrogen) from organic substances to prevent cell death and self-replication
E.g., found in the liver
176
What are proteasomes?
Organelles that help with the continuous destruction of unneeded, damaged, or faulty proteins is the function of tiny barrel-shaped structures consisting of four stacked rings of proteins around a central core called
177
What are mitochondria? What are their 4 main structures?
An organelle that generates most of the ATP through aerobic (oxygen-requiring) respiration and is self-replicating
4 structures:
1. External mitochondria membrane
2. Internal mitochondrial membrane
3. Mitochondrial cristae
4. Mitochondrial matrix
178
What is the nucleus and its functions?
Consists of a nuclear envelope with pores, nucleoli and chromosomes which exist as a tangled mass of chromatin in interphase cells
Functions:
- Nucleus pores control the movement of substances btw the nucleus and cytoplasm
- Nucleoli produce ribosomes
- Chromosomes consist of genes that control cellular structures and direct cellular functions
179
What is gene expression and name its 2 steps
Refers to the use of a gene's DNA as a template for the synthesis of a specific protein and occurs in 2 steps
1. Transcription
2. Translation
180
What is transcription?
The first step of gene expression; during which the information encoded in a specific region of DNA is transcribed (copied) to produce a specific molecule of RNA (ribonucleic acid) in the nucleus of a cell
Base pairs (DNA --> RNA):
A --> U
T --> A
G --> C
C --> G
181
What are the 3 types of RNA made from DNA during transcription?
1. mRNA = directs the synthesis of a protein
2. rRNA = joins with ribosomal proteins to make ribosomes
3. tRNA = binds to an amino acid and holds it in place on a ribosome until it is incorporated into a protein during translation
182
What is RNA polymerase?
An enzyme that catalyzes transcription of DNA and attaches at the promoter (a special nucleotide sequence and the segment of DNA where transcription begins)
183
What is a terminator in the context of transcription
A special nucleotide sequence where transcription of the DNA strand ends
When RNA polymerase reaches the terminator, the enzyme detaches from the transcribed RNA molecule and the DNA strand
184
Compare introns vs. exons
During transcription, not all parts of a gene code for a protein:
Introns = regions within a gene that do not code for parts of proteins
Exons = the regions within a gene that do code for segments of a protein
185
What is translation?
The second step of gene expression; a process when nucleotide sequence in an mRNA molecule specify the amino acid sequence of a protein, which is carried out by ribosomes in the cytoplasm
186
What are the 7 steps of translation
Starts at the A site --> P site (where the chain is located) --> E
1. An mRNA molecule binds to the small ribosomal subunit at the mRNA binding site
2. The large ribosomal subunit attaches to the small ribosomal subunit–mRNA complex, creating a functional ribosome
3. The anticodon of another tRNA with its attached amino acid pairs with the second mRNA codon at the A site of the ribosome
4. A component of the large ribosomal subunit catalyzes the formation of a peptide bond between methionine and the amino acid carried by the tRNA at the A site
5. Following the formation of the peptide bond, the resulting two- peptide protein becomes attached to the tRNA at the A site
6. After peptide bond formation, the ribosome shifts the mRNA strand by one codon
7. Protein synthesis ends when the ribosome reaches a stop codon at the A site, which causes the completed protein to detach from the final tRNA
187
Polyribosome
When several ribosomes attached to the same mRNA during translation
188
What is cell division? What are the 2 types?
The process by which cells reproduce themselves
2 types:
1. Somatic cell division
2. Reproductive cell division
189
What is somatic cell division?
One of two types; When a cell undergoes a nuclear division called mitosis and a cytoplasmic division called cytokinesis to produce 2 genetically identical cells with the same # of chromosomes as the original cell
E.g., any cell of the body other than germ cells
190
What is the cell cycle? What are the 3 main phases?
Mitosis: When a somatic cell duplicates its contents and divides in two (human cells, such as those in the brain, stomach, and kidneys, contain 23 pairs of chromosomes, for a total of 46)
Phases:
1. Interphase (G1, S, G2)
2. Mitosis M phase (prophase, metaphase, anaphase, telophase, cytokinesis)
191
What is interphase?
The first step of the somatic cell cycle when a cell is not dividing but replicates its DNA and produces additional organelles and cytosolic components in anticipation for division
192
What is mitosis (M phase)?
The second step of the somatic cell cycle when a cell is dividing and results in the formation of two identical cells, consists of a nuclear division (mitosis) and a cytoplasmic division (cytokinesis) to form two identical cells
193
What is reproductive cell division?
One of two types; Consists of a special two-step division called meiosis, in which the number of chromosomes in the nucleus is reduced by half and produces gametes
194
What is meiosis?
Sexual reproduction = the reproductive cell division that occurs in the gonads (ovaries and testes), produces gametes in which the number of chromosomes is reduced by half; genetic recombination occurs during meiosis
195
