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Biology 200-3 > Midterm 3-1 > Flashcards

Midterm 3-1 Flashcards

(65 cards)

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1
Q

What is glucose used for

A

cellular respiration, to build fats, carbohydrates, and other compounds. it is stored as starch or glycogen

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2
Q

what happens when glucose is oxidized

A

cells oxidize glucose via controlled redox reactions and use the released energy to make ATP

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3
Q

Distinguish between respiration and fermentation

A

Respiration completely oxidizes glucose to produce CO2 and H2O but fermentation only partially oxidizes glucose, producing small, reduced molecules as waste. Respiration releases more energy than does fermentation. Respiration releases more energy than fermentation

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4
Q

What are the four steps of cellular respiration

A

Glycolysis (breaks glucose to two pyruvates), pyruvate processing(forms acetly CoA), krebs cycle (acetyl CoA’s are oxidized to CO2), Electron transport and oxidative phophorylation (electrons from NADH and FADH2 provide energy to make a protein gradient)

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5
Q

Where is most of the ATP made

A

In step four when energy from the proton flow across a membrane is used to make ATP

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6
Q

What is cellular respiration

A

Any reaction that produces ATP using an electron transport chain

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7
Q

What is oxidative phosphorylation

A

The linkage of NADH and FADH2 oxidation with phosphorylation of ADP

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8
Q

What does glycolysiis tell you about evolution

A

The common ancestro of all living organisms probably used glycolysis to make ATP because practically all living organisms used glycolysis to make ATP because practically all organisms have glycolytic enzyme

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9
Q

In glycolysis, what is on the intermediate compounds

A

Alll intermediate compounds are phosphorylated, only glucose and pyruvate are not phophorylated

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10
Q

Why does glycolysis stop when boiled

A

There are enzymes involved during glycolysis, and they become inactivated in heat. A different enzyme for each step of glycolysis

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11
Q

Why did the fermentation reaction observed by the Buchners last longer when inorganic phosphate was added

A

it allowed for an increase inphophorylation. Glycolysis is limited by the amount of phosphate available

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12
Q

Where does glycolysis occur

A

cytosol

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13
Q

How is the initial energy investment paid off

A

the subsequent reactions. The sixth reaction reduces 2 NAD+, the seventh reaction produces 2ATP and the last reaction produces 2 ATP

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14
Q

What does glycolysis yield

A

2 NADH, 2 ATP, and 2 pyruvates per glucose

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15
Q

What is substrate level phophorylation

A

Enzymes catalyze the direct transfer of phosphates from a phophorylated intermediate to ADP

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16
Q

What would happen to glycolysis reactions if a cell ran completely out of ATP

A

It woud stop. ATP input is required for ATP output

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17
Q

How is glycolysis regulated

A

High levels of ATp inhibit Phosphofructokinase, the enzyme that catalyzes step three of glycolysis. The products of steps 1 and 2 can be used in other metabolic pathways, but step 3’s product is used only in glycolysis, making a good regulation point

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18
Q

How is ATp alos working as Feedback inhibition

A

Increased substrate concentration typically increases concentration rate. However ATP is both substrate and an end product of glycolysis, so ATPs inhibitory effect is a type of feedback inhibition

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19
Q

Why is feedback inhibition efficient

A

it imporoves pathway efficiency. Cells with lots of ATp do not need to make more. Thus natural selection favor individuals that are inhibited at high concentrations of ATP

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20
Q

Describe phosphofructokinase

A

it has 2 ATP binding sites: and active site where ATP is hydrolyzed, and a regulatory site where where ATP acts as an allosteric regulator. The active site has a greater affinity for ATP than the regulatory site

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21
Q

How does phosphofructokinase work

A

At low concentration ATP binds mostly to phosphofructokinases active site, but at high concentrations ATP also binds to the regulatory site causing a shape change that decreases enzyme activity

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22
Q

WHere does the pyruvate go after glycolysis

A

to the mitochondria

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23
Q

what does the mitochondria consist of

A

two membranes: inner=cristae, and between the inner and the cristae is the mitochondrial matrix

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24
Q

How does pyruvate cross the outer membrane

A

Through small pores

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25
inside the mitochondria, what happens to the pyruvate
pyruvate reacts with coenzyme A to produce acetyl CoA. CoA is a common enzyme that transfers acetyl groups to substrates
26
what is pyruvate dehydrogenase
this is the enzyme that catalyzes pyruvate and CoA. This is in the mitochondrial matrix
27
what is pyruvate processing produce
one CO2 and reduces one NAD+ to NADH. The remaining two carbons form the acetyl group transferred to CoA, making Acetyl CoA the final product
28
How does pyruvate dehydrogenous work as feedback inhibition
when ATP is plentiful, pyruvate dehydrogenous becomes phophorylated and changes shape such that catalysis is inhibited. High concentrations of CoA and NADH also inhibit pyruvate dehydrogenous by promoting its phosphoilation; in contrast, high concentrations of NAD+, CoA, or adenosine monophosphate (AMP) increase enzyme activity
29
How is pyruvate processing a key regulatory point
it undergoes both positive and negative control
30
what happens when carboxylic acids were added to cells
increase in cell respiration
31
Why is it called the citric acid cycle
the cycles start point, citrate, forms when pyruvate and the cycles endpoint, oxaloacetate are added to the cells. Citrate becomes citric acid when a proton is added
32
what is the product of the krebs cycle
3 NADH, 1 FADH2, and 1 GTP or ATP via substrate level phophorylation
33
where does the citric acid cycle occur
in the cytosol of prokaryotes in in the mitochondrial matrix of eukaryotes. Cycle turns twice per glucose since end product is two pyruvate
34
how is the citric acid cycle regulated
low ATP causes high reaction rates, whereas high concentration inhibits citric acid cycle
35
Where is the feedback inhibition occuring
in the Kreb cycle, it is when NADH binds to the enzymes active site as a competative inhibitor. when ATP binds in the other site, it is allosteric regulation
36
In total, how much of everything is made
10 NADH, 2FADH2, and 4 ATP per two oxidized pyruvates
37
where is most of the energy from glucose oxidation end up
In NADH or FADH2
38
What does glycolysis, pyruvate processing, and citric acid cycle all have in common
the transfer electrons from glucose to NAD+ and FAD, making NADH and FADH2, which carry the electrons to the final electron acceptor
39
Where is NADH oxidized
For eukaryotes: inner mitochondrial membranes | Prokaryotes: plasma membrane
40
What makes up the electron transport chain
molecules in the inner mitochondrial membrane that are involved in the oxidation of NADH and FADH2
41
What does the energy released by ETC used for
energy released by sequential redox reactions is used to pump proteins across the inner mitochondrial membrane, creating a proton gradient
42
What is Ubiquinone
also calle coenzyme Q, it is lipid soluble and easily moves throughout the inner mitochondrial membrane to transport electrons
43
How do ETC molecules differ
in electronegativity- their tendency to become oxidized or reduced
44
How are poisens used to research ETC
A poison inhibits an ETC protein causing ETC molecules that receive electrons before the poisoned states to stay in reduced state, whereas those downstream of the poison remain oxidized
45
Where does NADH or FADH2 donate electrons
to a flaven containing protein at the top of the chain for NADH, but for FADH2, to an iron-sulfer protein that passes elctrons directly to Q
46
What transfers electrons between complexes
Q and cytochrome c
47
What is the final electron acceptor
Oxygen, super high potential difference
48
What does Q do
it is known that when Q accepts electrons from complex I to II, it also gains protons from the matrix side. Q diffuses through the membrane. Q then diffuses through the membrane. Its electrons are transferred to complex II, and its protons are released into the intermembrane space
49
What is ATP synthase
it is an enzyme that both hydrolyzes and synthesizes ATP
50
What is the proton motive force
this is when the ETC pumps protons from the matrix to the intermembrane space. This would create an electrochemical gradient favoring the movement of protons back into the matrix
51
what is chemiosmosis
the production of ATP via a proton gradient
52
could ATP synthase still work if ETC was not there
yes, you only need a proton gradient
53
A compound called DNP can be used to poke holes in the inner mitochondrial membrane. What would this do to ATP synthesis by oxidative phosphorylation
proton gradient would be removed so it would stop
54
HOw does ATP synthase work
protons flow through the F0 unit (the base), causing the stalk connecting the two units to spin. The spinning deforms the F1 subunit (the knob) in a way that catalyzes the phophorylation of ADP to ATP
55
Where does most usable energy come from
ATP synthase from cellular respiration | this is oxidative phosphorylation
56
What aerobic respiration
using oxygen as a final acceptor of electron transport chains
57
What is anaerobic respiration
when there is no oxygen, and using other electron acceptors
58
why is oxygen the best electron acceptor
it has a high electronegativity. Its electron have very low potential energy. The large energy difference between NADH and O2 permits the generation of a large proton motive force for ATP production
59
Why is aerobic respiration more efficient
other methods produce less ATP making these cells grow slower than aerobic respirators. Aerobic outcompetes anaerobic respirators
60
What is fermentation
a pathway that oxidizes NADH back to NAD+ and allo glycolysis to continue producing ATP via substrate level phophorylation when the ETC electron acceptor is not available
61
What happens during fermentation
pyruvate or a molecule derived from pyruvate accepts electrons from NADH, regenerating NAD+. The molecule formed from the reduction of pyruvate is often excreted from the cell as waste
62
What is lactic acid formation
this produces lactate in addition to regenerating NAD+
63
what is alcohol fermentation
where pyruvats loses CO2 and is converted into acetylaldehyde, which accepts an electron from NADH to produce ethanol and NAD+
64
What does fermentation produce
2 ATP per glucose
65
What would happen if a winemaker followed the industrial process for making wine but then bubbled oxygen though the vats of grape juice instead of letting it sit undisturbed
it would produce a lot of water and CO2

Biology 200-3 (3 decks)

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