Exam 1 Review Flashcards
(140 cards)
1
Q
What is the “Cell Theory” of life?
A
- All organisms are composed of cells
- Cells are the structural unit of life
- Cells arise only from other cells
2
Q
Biologists generally agree that living cells all must have…
A
- A limiting boundary (plasma membrane = cell membrane)
- Carry out complex metabolism (chemical reactions)
- A mechanism of inheritance (DNA, RNA?)
3
Q
Are viruses living cells?
A
No, they are not living cells. Lack basic machinery for self replication. Dependent on host cell functions for propagation.
4
Q
Define Autopoietic
A
system capable of reproduction and self maintenance
5
Q
what are the 3 domains of life?
A
- Archaea
- Bacteria
- Eukarya
6
Q
What is Archaea?
A
archaebacteria, prokaryotic, has unique rRNA. Mostly anaerobic, lives in extreme environments (high temps, strong acids)
7
Q
What is Bacteria?
A
prokaryote, peptidoglycan cell wall.
8
Q
What is Prokarya (prokaryotes)?
A
“Before nucleus”
9
Q
What is Eukarya?
A
cells with “true nucleus”, cells with 1-2 flagella. Consist of animal, plant, fungi, protista kingdoms.
10
Q
What can Light microscopy view?
A
living or chemically fixed cells if dead, unstained or stained. Movements of living unstained cells.
cannot resolve individual molecules, but can determine where they are.
11
Q
What is fluorescence microscopy?
A
type of light microscopy. Used to visualize 1 component (eg. protein) in a cell.
process: stain specimen w dye. light excites the dye, which then emits its light, a filter only lets this filtered light through.
images are color on black background.
12
Q
what is Immunofluorescence microscopy
A
type of fluorescence microscopy.
uses antibodies to view protein localization
only dead cells can be viewed
only proteins of interest are visible, rest of cell is dark.
cannot resolve individual antibodies, 4 used for red & green.
13
Q
what is GFP?
A
Green Fluorescent protein, in fluorescense microscopy. fused onto protein of interest to follow proteins in living cells. Done by manipulating DNA sequence, chimeric.
14
Q
What is a TEM?
A
transmission electron microscope.
Resolve small objects
15
Q
What is SEM?
A
Scanning Electron Microscope, reveals details of cell surface.
grayscale pictures.
16
Q
What are prokaryotes?
A
bacteria and archaea domains. Many shapes but mostly small.
human body has more prokaryotic cells than eukaryotic cells.
17
Q
What type of wall do Bacteria have?
A
peptidoglycan layer cell wall, outside plasma membrane.
18
Q
Eukaryotic cells have many…
A
compartments. Metabolic processes segregated from one another.
19
Q
what is the difference between cytoplasm and cytosol?
A
Cytoplasm = everything inside plasma membrane, cytosol + organelles Cytosol = (fluid) everything inside plasma membrane and outside organelles.
20
Q
What was the very first orgnalle?
A
Nucleus. Process of invagination
21
Q
What is the C value paradox?
A
the amount of DNA content of a nucleus does NOT mean a complex organism.
22
Q
What is the difference between plant and animal cells?
A
plant cells (only) have vacuole, cell wall and chloroplasts.
23
Q
What is a vacuole?
A
plant cell containing majority of volume of the cell, exerts turgor pressure.
24
Q
What is the cell wall?
A
gives the cell is strength and rigidity. resists turgor pressure.
25
What constraints does a cell wall pose?
no cell movement/migration, no division, or cell to cell communication.
26
What is a chloroplast?
the photosynthetic organelle of plant cells
27
what is the origin of mitochondria and chloroplasts?
arose by endosymbiosis of bacterial cells.
28
What is a 'fact' in science?
a hypothesis that has been tested many times and cannot be rejected
29
What tenant of the cell theory is violated by the origin of life?
that all cells come from other cells.
30
What was the evolution of first cells?
RNA-> (translation) -> RNA + protein -> (transcription -> DNA + RNA + protein
31
Cell evolution likely sequence of events
1. Photosynthesis evolved first, to build of O2
2. formation of nucleus by membrane invagination
3. respiration evolves in prokaryotes
4. acquisition of mitochondria by endosymbiosis
5. acquisition of chloroplast by endosymbiosis
32
Why would RNA come before DNA?
because RNA can also act as an enzyme.
33
What came first mitochondria or chloroplasts?
mitochondria
34
Is covalent bond a strong or weak bond?
strong bond, formed when atoms share pairs of electrons
| example C-C
35
Is an Ionic bond strong or weak?
considered weak, because we are in an aqueous environment.
definition Stealing of electrons to make bond
36
Is a hydrogen bond strong or weak?
weak.
37
What is a polar covalent bond?
allow Hydrogen bonds, through partial negative charges with proton
38
How can macromolecules for a strong interaction?
through many weak chemical interactions, H or ionic bonds.
39
What chemical group is Alcohol?
HO-C bond, hydroxyl, hydrophilic
40
What chemical group is an Aldehyde?
O=C-H carbonyl group,
41
What chemical group is a ketone?
O= C - C
42
What makes up a carboxylic acid?
O=C-OH
43
What makes an Ester?
O=C-OH CH3 carboxylic acid + alcohol
44
What is an Amine?
NH2 - C
45
What is an Amide?
O=C-OH + NH2-C -> amide, protein structure
46
What is phosphoanhydride?
bonding of 2 Phosphates together
47
How does phosphoanhydride provide energy?
when 3 phosphates are bonded together in ATP, the break of the last 2 bonds provides energy for RNA and DNA
48
How do you create an Phosphate Ester?
bonding of hydroxyl/Alcohol with phosphate
49
How do you create an Acyl Phosphate?
bonding of carboxylic acid (O=COH )with phosphate
50
What are the 4 major groups of macromolecules?
Lipids, proteins, polysaccharides and nucleic acids
51
What are the building blocks for macromolecules?
Sugars (monosaccharides), fatty acids, amino acids, nucleotides
52
What is a condensation reaction?
a bond is formed and water is released.
| Monomer to Polymer
53
What is a hydrolysis reaction?
a bond is broken.
| Polymer to a monomer
54
What is the difference between an aldose and a ketose?
Aldose O=CH at end of chain, Ketose O=C is not at the end.
55
Are polysaccharides hydrophilic or hydrophobic?
Hydrophilic
56
What is the difference between an alpha and beta hydroxyl ring?
Beta has OH on top, Alpha has OH on bottom
57
What is glycogen?
energy storage, alpha(1-4) glucose with alpha(1-6) branches
58
what is amylose?
aka starch, is energy storage in plants, alpha(1-4) glucose (unbranched)
59
What is cellulose?
provides structural support, beta(1-4) glucose, straight chain. dietary fiber.
60
What is the most abundant organic polymer on Earth?
cellulose
61
Are membranes made?
No they are inherited.
62
Define amphipathic
having both hydrophilic and hydrophobic regions
63
What is the structure of a fatty acid chain?
head group = hydrophlic carboxylic acid
| tail = hydrophobic hydrocarbon
64
What is a characteristic of an unsaturated fatty acid?
has 1 or more cis double bonds, which cause a kink in the chain.
Does not pack well.
65
What is a triacyl glycerol?
3 fatty acids bonded to a glycerol, energy storage, more efficient way to store energy than glycogen
66
What is the phospholipid structure?
polar head group = phosphate + polar group like glycerol
| hydrophobic tail = fatty acid side chain
67
What are three major types of membrane lipid molecules?
Phospholipids, sterols, glycolipids
68
What are the 2 states of membrane fluidity (viscosity)?
gel and liquid state
69
What factors attribute to membrane fluidity?
saturation, length, cholesterol level
70
How does fatty acid saturation affect fluidity?
more unsaturated, tails don't pack well, lowers the transition temperature, favors liquid state
71
How does fatty acid length affect fluidity?
shorter the chain the interaction is less, lowers the transition temperature (melting point), favors liquid.
72
How does the presence of cholesterol affect fluidity?
broadens the temperature range over which liquid-gel transition occurs.
73
How would a cell respond to an increase in temperature?
If temperature is raised, the cell will be more liquid. It will try to lower its fluidity by being more ordered, more rigid.
74
How does cholesterol play into plasma membrane?
rings stiffen the membrane, decreases permeability and fluidity of membrane.
75
What does cholesterol do to the membrane at high temperatures?
stiffens it, makes it less fluid. Protects cell wall by being resistant to heat and denaturing.
76
What does cholesterol do to the membrane at low temperatures?
less cholesterol found in membranes, prevents membrane from gelling, more fluidity.
77
Is cholesterol good for health?
yes in low amounts it maintains proper membrane fluidity.
no in high amounts builds plaque, heart disease.
78
Where is a glycolipid found?
in outer leaflet of plasma membrane
79
Where are phospholipids made?
in the ER
80
What is scramblase?
a protein that randomly transfers phospholipid between leaflets from ER
81
What is flippase?
protein from Golgi transfers specific phospholipids to leaflet facing cytosol.
82
What is floppase?
protein that moves phospholipids from cystolic to lumen leaflet
83
How is membrane assymetry maintained?
by low frequency flip flop
84
What do you use to destroy a membrane?
detergent. Phospholipids are removed.
85
Lipid Bilayer permeability, what can go through?
| Small nonpolar M, small uncharged polar M, large uncharged polar M, ions
small nonpolar M can easily pass through.
small uncharged polar M, can not pass, need transport.
large uncharged polar M can not pass, need transport.
Ions cannot.
86
What macromolecule is the most functionally diverse and prolific?
proteins
87
What amino acid group is negatively charged and acidic?
carboxylic acid
88
What amino acid group is basic and positively charged?
amino group
89
What amino acid group is polar and uncharged?
hydroxyl
90
What amino acid group is nonpolar?
hydrocarbon chains
91
What is a peptide bond?
when tow amino acid molecules are joined. covalent bond.
92
What are the 4 levels of protein structure?
Primary - single strand, linear
Secondary - shapes, alpha helix, beta sheet
Tertiary - 3D conformation, polypeptide chain
Quaternary - two or more polypeptide chains complex.
93
What happens if there is improper protein folding?
Disease. Prion, misfolded protein. Build up, aggregates can pile up in the brain.
94
what structure gives silk its strength?
beta sheet
95
What structure creates a polypeptide domain?
tertiary
96
What structure creates a functional protein?
quaternary
97
How do you lower the activation energy?
use enzymes
98
What is the 2nd law of thermodynamics?
entropy (disorder), always increase randomness.
Cells give off heat, add to entropy
99
dG is negative means?
reactions occur spontaneously, no energy required.
100
Do enzymes effect dG?
no they do not, only activation energy
101
Do enzymes change reaction rates?
yes, they accelerate them
102
How do enzymes lower activation energy?
hold substrates in positions that encourage reactions to occur
change ionic environment of substrates,
put physical stress on substrate, bending.
103
How are enzymes regulated?
by inhibitor binding, phosphorylation causes conformation change
104
What energy result comes from ATP->ADP
hydrolysis rxn, dG-
105
What energy result comes from binding bonds?
condensation rxn, dG+
106
What is the Electrochemical gradient?
voltage difference across membrane due to unequal concentrations of ions
107
dG positive means?
energy is required
108
How do cells transport an impermeable molecule against its EC gradient?
by coupling with a dG - reaction.
109
What dG - reactions are good for coupling?
light, ATP hydrolysis, electrochemical ion gradient
110
what is a transporter protein?
carrier protein, undergoes conformational change for transport.
111
what is a channel protein?
hydrophilic pore, or hole for transport. No shape change needed.
112
How do channel proteins work?
multiple helices form aqueous pore due to polar and uncharged R groups. Like a tunnel
113
What are the 3 types of active transport?
ATP driven, light driven, coupled pump
114
What is an ATP driven pump?
an active transport pump, uses ATP from hydrolysis
115
What is light driven pump?
uses energy from light
116
What is a coupled pump?
uses energy from an ion moving down its EC gradient
117
Define chemiosmotic coupling?
generating an electrochemical gradient and harnessing EC gradients to do work
118
Catabolic vs Anabolic?
catabolic is dG - breakdown of molecules
| anabolic is dG + synthesis of molecules
119
What is an autotroph?
derives energy from sunlight, like plants
120
What is a reduction reaction?
a molecule gaining an electron
121
What is a oxidation reaction?
a molecule donating an electron. dG-
Ex. NADPH -> NADH+
122
What molecules are part of reducing power?
NADH and NADPH
123
What forms of energy are part of EC Gradient?
Na+ and H+
124
What forms of energy is part of glycolysis?
covalent bonds ATP, reducing power NADH and NADPH
125
Where in the cell is ATP made?
Bacterial - Plasma membrane
Mitochondria - inner membrane
Chloroplast - thylakoid membrane
126
What is ATP Synthase?
in outer membrane, rotary machine that makes ATP through proton exchange
127
How does ATP Synthase work?
F0 transports H+ across membrane, turns rotor ring F0 alpha. Which then changes conformation of F1 ATPase head. 3H+/ATP
128
What is mechanism of ATP synthesis?
Gamma subunit rotates to make conformational changes in Beta subunits allow them to bind ADP + Pi and make ATP.
129
What are the 3 conformations of the Beta subunit cycle?
1. Open = ADP + Pi bind
2. Loose = loosely holds ADP + Pi
3. Tight = makes ATP, released
3 H+/ATP
130
What forms of energy is "cash in pocket"?
EC gradient (Na+/H+), covalent bonds (ATP), reducing power (NADH, NADPH)
131
What is the chloroplast structure?
inner and outer membrane
| thylakoids
132
What is the stroma?
area between inner membrane and thylakoids
133
What is the 1st step of photosynthesis?
light reaction causes excited electron, starts e- transport chain, generates H+ EC gradient
134
General steps of light reaction
4 e- enter PS2, inside thylakoid lumen 2H20 split to make 4 H+, then 4 H+ pulled from stroma into lumen, then in PS1 NADP+ reduced to NADPH in stroma
135
where is the reaction center located?
in antenna complex of photosystem 2.
136
What does the reaction center do?
site of charge separation. Chlorophyll donates high energy e- to e- transport chain
137
What is the most abundant enzyme on earth?
rubisco
138
What is CO2 fixation?
aka dark reaction
CO2 + rubisco -> water and food
139
What is carbon fixation cycle steps?
1. CO2 fixation (3 CO2 convert to 3C) 2. Phosphorylation (6 ATP -> 6 ADP) (3C) 3. Reduction (6 NADPH -> 6 NADP+) (3C) 4. Net yield (G3P) (3C) 5. Phosphorylation (3C) (3 ATP -> 3 ADP)
140
What do you need to know about carbon fixation cycle?
3 CO2 converted to 3 carbon organic molecule (G3P)
Cost: 9 ATP and 6 NADPH
