Chapter 7 - The Cycles of a Cell Flashcards

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1
Q

What are autotrophs?

A

Converts radiant energy into chemical energy (self feeders)

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2
Q

What are heterotrophs?

A

Live on organic compounds that they consume (fed by others)

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3
Q

What is cellular respiration?

A

The central process in the energy metabolism which involves oxidation of organic compounds and using energy released to form ATP.

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4
Q

How is energy extracted from organic mixtures?

A

By rearranging C–H bonds via oxidation/reduction.

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5
Q

What is aerobic respiration?

A

When the electron acceptor is oxygen.

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6
Q

What is anaerobic respiration?

A

When the electron acceptor is an inorganic molecule other than oxygen.

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7
Q

What is fermentation?

A

When an organic molecule accepts electrons.

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8
Q

What is the chemical equation for burning carbohydrates?

A

C6H12O6 + 6 O2 –> 6 CO2 + 6 H2O + energy (heat and ATP)

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9
Q

What makes up NAD+?

A

Two nucleotides which are nicotinamide monophosphate (NMP) and adenosine monophosphate (AMP) which are joined head-to-head by their phosphate groups.

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10
Q

How does NAD+ become NADH?

A

NAD+ acquires 2 electrons and a proton from the active site of an enzyme and is reduced to NADH.

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11
Q

What is substrate-level phosphorylation?

A

When ATP is formed by transferring a phosphate group directly to ADP from a phosphate-bearing intermediate or substrate.

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12
Q

What is oxidative phosphorylation?

A

When ATP is synthesized by the enzyme ATP synthase, using energy from a proton (H+) gradient.

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13
Q

How is the proton (H+) gradient formed?

A

High-energy electrons removed by oxidation of glucose passes down an electron transport chain.

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14
Q

What is the process of Glycolysis?

A

Converts glucose into 2 3-carbon molecules of pyruvate.

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15
Q

Where does glycolysis take place?

A

In the cytoplasm

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16
Q

How many net ATPs does glycolysis yield?

A

2 ATP

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17
Q

How many steps is the first half of glycolysis?

A

5 reactions

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18
Q

What happens in the first 3 steps of glycolysis?

A

It primes glucose by changing it into a compound that can be readily cleaved into 2 3-carbon phosphorylated molecules.

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19
Q

True of False: The first half of glycolysis needs 2 ATP in order to prime glucose.

A

True: Glycolysis begins by expending 2 ATP to transfer phosphate to each end of the glucose. This produces a 6-carbon molecule with two phosphates.

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20
Q

What is formed in the next 2 reactions of the first half of glycolysis?

A

2 3-carbon monophosphate sugars called glyceraldehyde-3-phosphate (G3P).

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21
Q

What is the 2nd to last step of glycolysis?

A

Each G3P is oxidized transferring 2 electrons and 1 proton to NAD+ forming NADH. A molecule of Pi is added to G3P to produce 1 3-biphosphatoglycerate (BPG).

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22
Q

What is the last step of glycolysis?

A

The phosphate incorporated is transferred to ADP by substrate-level phosphorylation in an exergonic reaction. 2 net ATP is formed

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23
Q

How much energy is produced with glycolysis?

A

14.6 kcal of energy per glucose

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24
Q

True or False: Cells contain a large amount of NAD+

A

False: a cell must oxidize NADH back to NAD+ in order for glycolysis to continue

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25
Q

What is the chemical equation for glycolysis?

A

glucose + 2 ADP + 2 Pi + 2 NAD+ –> 2 pyruvates + 2 ATP + 2 NADH + 2 H+ + H2O

26
Q

Where does the citric acid cycle take place?

A

In the mitochondria

27
Q

How is pyruvate harvested?

A

Pyruvate is oxidized to produce a 2-carbon compound and CO2 with the electrons transferred to NAD+ to produce NADH.

The 2-carbon compound is oxidized to two molecules of CO2 by the reactions of the citric acid cycle.

28
Q

What is the term of pyruvate’s oxidation?

A

decarboxylation

29
Q

How is acetyl-CoA formed?

A

By the decarboxylation of pyruvate from cleaving off one of pyruvate’s three carbons. The remaining 2-carbon compound is acetyl-CoA.

30
Q

What carbon group is fed into the citric acid cycle?

A

acetyl-CoA

31
Q

What is acetyl added to?

A

The acetyl groups is added to 4-carbon acid oxaloacetate

32
Q

What does acetyl turn into in the CAC?

A

It produces citrate

33
Q

What happens to citrate in the CAC?

A

Citrate converts back to oxaloacetate, generating CO2 and transferring electrons and protons to the electron carriers NADH and FADH2.

34
Q

How many ATP is generated by the oxidation of citrate?

A

1 ATP

35
Q

True or False: The citric acid cycle produces a lot of ATP but does not produce a lot of NADH.

A

False: Very few ATP is generated but a large amount of NADH is generated for use in the electron transport chain.

36
Q

How many reactions are in the citric acid cycle?

A

9 reactions

37
Q

What is the first reaction of the CAC?

A

Condensation: Citrate is formed by joining acetyl-CoA to oxaloacetate.

38
Q

What happens in reactions 2 and 3 of the CAC?

A

Isomerization: The hydroxyl (-OH) group of citrate must be repositioned. A water molecules is removed from one carbon and moved to another producing Isocitrate.

39
Q

What is reaction 4 of the CAC?

A

The first oxidation: Isocitrate is oxidized in a decarboxylation reaction. Yields a par of electrons that reduce NAD+ to NADH. A central carboxyl group splits off to form CO2, produces A-ketoglutarate

40
Q

What is reaction 5 of the CAC?

A

The second oxidation: A-ketoglutarate is decarboxylated by a multienzyme complex. CO2 is removed and joins to coenzyme A forming Succinyl-CoA. Two more electrons are extracted and reduce another NAD+ to NADH.

41
Q

What is the 6th reaction of CAC?

A

Substrate-level phosphorylation: The bond of succinyl-CoA is cleaved and drives the phosphorylation of guanosine diphosphate (GDP) forming guanosine triphosphate (GTP). GTP can be converted into ATP. The molecule that remains is succinate.

42
Q

What is the 7th reaction of the CAC?

A

The third oxidation: Succinate is oxidized to fumarate. FAD is the electron acceptor.

43
Q

What are reactions 8 and 9 of the CAC?

A

Regeneration of oxaloacetate: a water molecule is added to fumarate to form malate. Malate is oxidized to oxaloacetate and two electrons reduce NAD+ to NADH.

44
Q

How many NADH molecules are formed in the citric acid cycle?

A

10 molecules

45
Q

How man FADH2 molecules are formed in the CAC?

A

2 molecules

46
Q

How many net ATP molecules are formed in the CAC?

A

4 molecules.

47
Q

What is the best method to understand the CAC?

A

Follow the electrons

48
Q

Where does the electron transport chain take place?

A

In the inner mitochondrial membrane

49
Q

What is the first to receive the electrons in the ETC?

A

NADH dehydrogenase

50
Q

What is the carrier called that passes electrons to a protein called the bc1 complex?

A

Ubiquinone

51
Q

What is the next carrier called that carried electrons to the cytochrome oxidase complex?

A

Cytochrome C

52
Q

What does the cytochrome oxidase complex do?

A

It uses 4 electrons to reduce a molecule of oxygen. Each oxygen atom combines with two protons to form water.

53
Q

How does the proton gradient form in the ETC?

A

The flow of highly energetic electrons induces a change in the shape of proton pump proteins which causes them to transport protons across the membrane.

54
Q

What is chemiosmosis?

A

The chemical formation of ATP is driven by a diffusion force similar to osmosis

55
Q

How does ATP synthases work?

A

Most of the protons that re-enter the matrix pass through ATP synthase which uses the energy of the gradient to catalyze the synthesis of ATP from ADP and Pi.

56
Q

How many ATP is produced by NADH?

A

2.5 ATP

57
Q

How many ATP is produced by FADH2?

A

1.5 ATP

58
Q

How many ATP is yielded in aerobic respiration?

A

26-28 ATP

59
Q

True or False: Bacteria have a higher ATP production.

A

True: Bacteria can produce up to 30-32 ATP.

60
Q

What is produced in alcohol fermentation?

A

NAD+ and ethanol which is used to create wine.

61
Q

What do muscle cells produce?

A

Converts pyruvate into lactic acid and regenerates NAD+.