exam 4 Flashcards
(120 cards)
1
Q
is direct burning of sugar or stepwise oxidation of sugar better
A
stepwise oxidation because the energy that is released at each step can be stored whereas the direct burning is fully lost as heat
2
Q
what stores the energy that is released during stepwise oxidation
A
activated carriers
3
Q
what types of energy are typically released in stepwise oxidation
A
ATP and NADH
4
Q
which releases more energy, the direct burning or the stepwise oxidation of sugar
A
neither, they release the same amount of energy
5
Q
what uses the direct burning of sugar
A
nonliving systems
6
Q
what uses the stepwise oxidation of sugar
A
living cells
7
Q
what is the chemical reaction that occurs when burning/oxidating sugar
A
sugar + O2 –> CO2 + H2O
8
Q
does direct burning or stepwise oxidation of sugar have more activation energy
A
the cumulative activation energy is the same, but direct burning needed to overcome the large hump all at once whereas stepwise has smaller activations each step that can be overcome by enzymes that work at body temperature
9
Q
where is energy from food molecules harvested
A
in the mitochondria
10
Q
draw and label the parts of mitochondria
A
should include:
- outer membrane
- inner membrane
- intermembrane space
- matrix
11
Q
how many stages does it take to break down food molecules
A
3
12
Q
what is the first stage of breaking down food molecules
A
breakdown of large food molecules to simple subunits
13
Q
what are the subunits that large food molecules are broken down into
A
proteins to amino acids, polysacharrides to simple sugars, fats to fatty acids and glycerol
14
Q
does step 1 of food breakdown release energy
A
yes, but it’s released as heat and so can’t be used to make ATP
15
Q
what is the second step of food breakdown
A
GLYCOLYSIS - breakdown of simple subunits into acetyl CoA
16
Q
does step 2 of food breakdown release energy
A
yes, very small amounts of ATP and NADH
17
Q
what is the third step of food breakdown
A
THE CITRIC ACID CYCLE - the acetyl group in acetyl CoA is oxidized to H2O and CO2
18
Q
does step 3 of food breakdown release energy
A
yes, large amounts of ATP are produced
19
Q
where do the steps of food breakdown occur (1, 2, and 3)
A
1 - outside the cell
2- in the cell’s cytosol
3 - in the mitochondria of the cell
20
Q
what are the products of the oxidation of food reaction
A
ATP, NADH, CO2, H2O
21
Q
what is glycolysis
A
this is the process of extracting energy from splitting sugar into pyruvate
22
Q
how much energy does glycolysis need to start
A
2 ATP
23
Q
what are the products of glycolysis
A
the one glucose molecule and 2 ATP used will create 2 pyruvates and 4 ATP and 2 NADH
so net results of 2 pyruvate 2 atp 2 nadh
24
Q
T/F glycolysis pyruvate is a 3-carbon made from a 6-carbon glucose
A
TRUE the molecule starts with 6 and is split into 3 and 3
25
what other process can produce ATP but at a much smaller amount that glycolysis
fermentation is fast but doesn't produce as much per molecule of glucose so glycolysis is better
26
T/F glycolysis couples many processes to each other
true, this is mostly seen with oxidation steps coupled with energy storage steps
27
what has to happen to the pyruvate after glycolysis before the citric acid cycle
it has to be converted to acetyl CoA and CO2
28
where does the pyruvate get broken down before the citric acid cycle
the mitochondrial matrix
29
what enzyme helps break down the pyruvate into acetyl CoA and CO2 before the citric acid cycle
pyruvate dehydrogenase complex
30
what does the citric acid cycle do
oxidizes acetyl groups to CO2 which creates NADH
31
what process drives the synthesis of the majority of the ATP in most cells
electron transport!!
32
what is another name for the electron transport chain's process
oxidative phosphorylation
33
what two energy molecules does the electron transport chain use and why
NADH and FADH2 from the citric acid cycle because they provide high energy electrons
34
how does H+ get to the other side of the inner membrane
this is coupled with the electron transfer so that the favorable transfer will pump the unfavorable H+ out of the membrane
35
why would animal cells store glucose
they would do this so that they can use the glycogen in times of need to convert that into energy
36
T/F fats are stored outside of cells
FALSE fats are stored inside cells in fat droplets
37
what do plant cells store in their chloroplasts
starch granules and fat droplets
38
what energy molecule donates high energy electrons to the electron transport chain
NADH
39
what is the purpose of the electron transport chain
to move electrons so that that favorable reaction can couple with pumping H+ ions across the membrane against their gradient
40
what are the two complexes that the electron in the electron transport chain go through
ubiquinone and cytochrome c
41
why is it so hard to push the H+ out of the membrane in the oxidative phosphorylation stage
because both the voltage (membrane potential) and the concentration (pH) gradient are pushing into the cell, so there is no reason why the H+ would want to be outside the cell if their electrochemical gradient is so strongly pushing in
42
what acts as a turbine to generate energy when the H+ comes back into the cell
ATP synthase is the motor
43
what is the energy that the ATP synthase generates used for
to attach phosphate to ADP which creates ATP which is the end product of the metabolism process
44
where does oxidative phosphorylation occur
mitochondria
45
where does photosynthesis occur
chloroplast
46
T/F mitochondria can not divide
FALSE the mitochondria can divide like a bacteria (since it is thought to have evolved from bacteria)
47
what is similar about mitochondria and chloroplasts
both have DNA, both make RNA and proteins
both organelles have the membranes used for ATP production
48
T/F mitochondria are typically located closer to where ATP is needed
TRUE there is more mitochondria in muscle cells and sperm cells for contraction and movement
49
T/F mitochondria form spherical shapes when multiple are together
FALSE they form elongated, tubular networks that extend through the cytoplasm
50
what are the four parts of the mitochondria
matrix (inside inside), inner membrane, outer membrane, intermembrane space (between membranes)
51
what is a hydride ion and what molecule is it found on that we use in the electron transport chain
hydride ion has two extra electrons instead of just one, so it produced two electrons when it is removed from NADH
52
T/F ATP synthase can be reversed
TRUE the atp synthase protein in the membrane can allow H+ ions to leave the membrane again if it's along their gradient, and this would take ATP and turn it back into ADP and P
53
what else is the H+ gradient used for
to couple with bringing the pyruvate into the matrix of the cell
to couple with bringing the phosphate into the matrix of the cell
54
what can move freely into the outer membrane of the mitochondria
ADP, ATP, phosphate and pyruvate
55
what percent of energy is captured from cellular respiration
about 50% is lost as heat, and the other 50% can be used
56
how many total ATP are yielded per glucose at the end of all the processes
30
57
what are uncoupling agents
these are H+ carriers that allow hydrogen ions back into the matrix without going through ATP synthase
58
how was ATP synthase found to work
there were four experiments to see which produced energy:
- just H+ gradient (no energy)
- H+ gradient and ATP synthase (made energy)
- just ATP synthase (no energy)
- H+ gradient, ATP synthase, uncoupling agent (no energy)
59
what is the redox potential
a measure of electron affinities
basically how badly a molecule wants to be given an electron
high means they want to receive an electron, low means they want to donate an electron
60
does a high or low redox potential want to donate electrons
a low redox wants to donate electrons to a high redox
61
does redox potential increase or decrease as the electron transport chain occurs
at the beginning, the redox potential is low, but by the end, the redox potential is very high
62
what is the extra compartment that the chloroplast has that the mitochondria doesn't have
thylakoids arranged in stacks called grana
63
what are the parts of the chloroplast
outer membrane, inner membrane, stroma (between inner and thylakoid membranes), thylakoid membrane (containing chlorophyll)
64
in photosynthesis, where is the light captured
in the chlorophyll in the thylakoid membrane
65
what wavelengths (colors) of light do chlorophylls capture
blue and red are absorbed, leaving practically just green and yellow and teal which makes plants look green
66
what is the structure of a chlorophyll molecule
ring at the top that absorbs light, hydrophobic tail that holds molecule in place
67
T/F light will bounce randomly between chlorophylls
TRUE it wont stop until it hits the special pair dimer chlorophyll
68
where is the special pair located
in the reaction center within the thylakoid
69
where is the electron in the special pair given to after it gets to the reaction center
mobile electron carrier takes the electron
70
where does the mobile electron carrier take the electron it picked up
it takes it to the electron transport chain
71
T/F photosystem II comes before photosystem I
TRUE
72
what do the two photosystems generate
ATP and NADPH
73
what is the outside source of electrons that go into photosystem II
water
74
are water electrons high or low energy state, and what turns it into the other one
starts low, but the light energy turns the energy of the electrons higher
75
where do the electrons go after photosystem II
to an electron transport chain that makes ATP
76
what is the terminal electron acceptor
the chlorophyll of photosystem I that collects the electron after the electron transport chain
77
does photosystem I start at a higher or lower redox potential than photosystem II
I starts at a lower redox potential, but this is higher than where II ended
78
what are the high energy electrons in photosystem I used to make
they are given more energy from the light electrons in the chlorophyll in photosystem I, and these are then used to make NADPH
79
where are the photosystems located
in the thylakoid membrane
80
what are the ATP and NADPH generated from the photosystems used to make
they make sugar from CO2
81
how is O2 a byproduct from photosystemII
when the water is giving it's electrons, the O2 is being released as a byproduct
82
what is carbon fixation
this is converting carbon dioxide into sugar molecules
83
what is the enzyme that catalyzes carbon fixation and what is it's speed
rubisco works at 3 reactions per second which is super slow
84
what are the things needed to make the carbon fixation cycle happen
3 CO2 go in
9 ATP and 6 NADPH are used
1 sugar produced
85
what does the plant cell do with the sugar that was generated
it can either be stored as a starch or immediately used to make ATP in the mitochondria
86
what is cell signaling used for
for cells to respond to stimuli in the environment and from other cells
87
what is signal transduction
one type of signal is converted into another
88
what is endocrine signaling
hormones secreted from endocrine glands go into the bloodstream and are widely distributed throughout the body to other cells to be received
89
what is paracrine signaling
a signaling cell releases signals and their local neighboring cells will receive them
90
what is neuronal signaling
a specialized form of paracrine signaling where the signal travels down the axon and reaches the nerve terminal where the neurotransmitters are released onto other target cells to be received
91
what is contact-dependent signaling
membrane-bound signal molecule binds to the receptor protein on another cell
92
what is the different between cell-surface receptors and intracellular receptors
cell-surface:
- bind to signal molecules outside of the cell and generate signals inside the cell
intracellular:
- when signal molecules can pass through the membrane and bind to receptor inside the cell and typically will send signals inside a different organelle like the nucleus
93
T/F a signal molecule always makes all cells do the same thing
FALSE a signal molecule can induce different responses within different cells
94
what does acetylcholine do in a heart pacemaker cell
decrease heart rate
95
what does acetylcholine do in a salivary gland cell
secrete more saliva
96
what does acetylcholine do in a skeletal muscle cell
contract the muscle
97
T/F animal cells depend on multiple signals to create a response
TRUE the signals being received tell the cell what process to do
98
when does a cell want to do apoptosis
when it's deprived of the necessary survival signals
99
T/F cell responses to signals are always the same speed
FALSE there are some that take less than a second and some that can take hours
100
what is positive feedback
where the signal turns on the response which activates more of the signal and this keeps the loop going
101
what is negative feedback
where the signal turns on the response which then inhibits the signal so the process stops
- like a thermostat
102
what are switch proteins
proteins that activate or inactivate when something happens to the signal molecule on it
- phosphate binds
- GTP turns to GDP
103
how are monomeric GTPases controlled
by two regulatory proteins
- GEF
- GAP
104
what is GEF
guanine exchange factor exchanges GDP for GTP and turns the monomeric GTPase on
105
what is GAP
GTPase activating protein hydrolyses GTP to GDP and switches the monomeric GTPase off
106
what are the three types of cell surface receptors
ion-channel-coupled
g-protein-coupled
enzyme-coupled
107
what are ion-channel-coupled cell-surface receptor proteins
a signal molecule binds to the ion channel letting the ions in along their gradient
108
what are g-protein-coupled cell-surface receptor proteins
a signal molecule binds to the receptor which activates the g-protein nearby which activates the enzyme which can carry out a process
109
what are enzyme-coupled cell-surface receptor proteins
a signal molecule in the form of a dimer binds to the protein to activate it or activate a nearby enzyme (usually a kinase)
110
what is the g-protein-coupled receptor proteins structure across the membrane
7 alpha helices
111
how is the g protein activated once the signal activates the receptor protein
this promotes the alpha subunit to release GDP and pick up GTP which activates all three parts of the g protein
112
T/F the activated receptor protein in g-protein-coupled responses can only work once
FALSE this receptor protein can cause many g-proteins to activate
113
how does a g-protein become inactivated
when it binds to its target protein, it can then hydrolyze the GTP into GDP and this inactivates it, which makes it then reattach to a beta gamma complex (if it disattached)
114
T/F g-proteins can activate ion channels
TRUE the activated beta gamma complex can open an ion channel
115
what are second messengers
these are small messenger molecules that are released from enzymes that the g-proteins activated
116
what is a common second messenger
cyclic AMP
117
what synthesizes cyclic AMP
adenylyl cyclase
118
what degrades cyclic AMP
cyclic AMP phosphodiesterase
119
T/F the concentration of cyclic AMP can rise rapidly in response to an extracellular signal
TRUE something like serotonin can trigger the release of a lot of these second messengers
120
