7.4 The Citric Acid Cycle Flashcards Preview

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Flashcards in 7.4 The Citric Acid Cycle Deck (23)
1

the citric acid cycle is the stage in cellular respiration in which:

fuel molecules are completely oxidized

2

Describe the outcomes of the citric acid cycle:

the acetyl group of acetyl-CoA is completely oxidized to carbon dioxide, the chemical energy is transferred to ATP by substrate-level phosphorylation and to the reduced electron carriers NADH and FADH2

3

by producing NADH and FADH2, the citric acid cycle is able to supply electrons to the:

electron transport chain, leading to the production of much more energy in the form of ATP

4

the citric acid cycle takes place in the:

mitochondrial matrix

5

the citric acid cycle is composed of:

8 reactions

6

the starting molecule is:

oxaloacetate and is regenerated at the end

7

in the first reaction, the 2-carbon acetyl group of acetyl-CoA is transferred to:

a 4-carbon molecule of oxaloacetate to form the 6-carbon molecule citric acid

8

the last reaction in the citric acid cycle regenerates a molecule of:

oxaloacetate, joining to a new acetyl group and allowing the cycle to continue

9

the citric acid cycle results in the complete oxidation of:

the acetyl group of acetyl-CoA

10

how many carbons are eliminated during the cycle?

2 carbons that are released as carbon dioxide

11

which reaction is the source of carbon dioxide released during cellular respiration?

the citric acid cycle

12

the oxidation reactions that produce carbon dioxide are coupled with:

the reduction of the electron carrier NAD+ to NADH

13

how many reduced electron carriers does the citric acid cycle produce?

3 NADH, 1 FADH2 per turn of the cycle

14

one of the reactions in the citric acid cycle uses substrate-level phosphorylation to generate a molecule of:

GTP

15

GTP can transfer:

its terminal phosphate to transform ADP to form ATP

16

what is the only substrate-level phosphorylation reaction in the citric acid cycle?

the production of GTP

17

what are the overall products produced from a single molecule of glucose into two molecules of acetyl-CoA?

2 molecules of ATP, 6 molecules of NADH, 2 molecules of FADH2

18

some bacteria run the citric acid cycle in reverse? how does this process work then?

carbon dioxide is incorporated into organic molecules, requires energy such as sunlight or chemical reactions

19

the intermediates generated step by step in the citric acid cycle provide:

the building blocks for synthesizing the cell's key biomolecules

20

pyruvate is the starting point for the synthesis of:

sugars and the amino acid alanine

21

acetate is the starting point for the synthesis of:

lipids

22

oxaloacetates is modified to form:

different amino acids and pyrimidine bases

23

what suggests that the citric acid cycle evolved early?

because the centrality of the citric acid cycle to both the synthesis of biomolecules and to meeting the energy requirements of cells suggested it appeared in the first cells to feature metabolism