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Principles: biochemistry > The Catabolism of Pyruvate > Flashcards

Flashcards in The Catabolism of Pyruvate Deck (40)
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1

Only limited amounts of ______ are present in a cell

Glycolysis reduces ____ to ____ + ___

NADH must be __-____ to let glycolysis continue

Only limited amounts of NAD+ are present in a cell

Glycolysis reduces NAD+ to NADH + H+

NADH must be re-oxidised to let glycolysis continue

2

how is NAD+ regenerated?

oxidative metabolism of pyruvate OR (anaerobic metabolism of pyruvate to lactate

3

NADH delivers electrons to what?

the respiratory chain

4

glycolysis takes place in ____

cytoplasm

5

where does the TCA cycle happen

in the mitochondria

6

the inner membrane contains _____ for ___ ___ ___, ___ synthase, and transport proteins

contains proteins for electron transport
chain, ATP synthase, and transport proteins

7

what is contained in the matrix of the mitochondria?

enzymes of the TCA cycle

8

pyruvate has to cross two membranes o get to the matrix for the TCA cycle.

It crosses the first _____ as it is negatively charged but needs ____ ____ to move across the inner membrane

passively, facilitated diffusion

9

what gradient drives the import of pyruvate into the matrix?

the pH gradient as there is a tnedency for protons to move to the matrix - creating the gradient

10

what is the transporter responsible for the movement of pyruvate into the matrix?

pyruvate /H+ symporter

11

___ gradient drives the movement of Phosphoate (Pi) into the matrix too?

pH

12

___ gradient drives the exchange of ATP ___ of the matrix and ADP ___ the matrix

voltage gradient, ATP out and ADP in

13

once in the matrix, how is pyruvate metabolised to Acetyl coA?

The -________ ____ -______ catalyses the____ _______ of pyruvate to acetyl-CoA

The pyruvate dehydrogenase complex (PDC) catalyses the oxidative decarboxylation of pyruvate to acetyl-CoA

14

how many enzymes make up the PDC?

3

15

____ activity determines glucose oxidation in well oxygenated
tissues.

PDC

16

the reaction by the PDC is _____

The reaction is irreversible. Acetyl-CoA cannot be converted
back to pyruvate.

17

reactions of PDC

1. pyruvate loses ____ and hydroxyethyl TPP (HETPP) is formed
2. hydroxyethyl group is transferred to ____ ___ and oxidaised to form ___ ______
3.____ group is transferred to____
4. dihydrolipoamide is reoxidised

1. pyruvate loses CO2 and hydroxyethyl TPP (HETPP) is formed
2. hydroxyethyl group is transferred to lipoic acid and oxidised to form acetyl dihydrolipoamide
3.acetyl group is transferred to CoA
4. dihydrolipoamide is re-oxidised

18

what are the bi-products of the PDC reactions

CO2, and NAD+ is reduced to NADH and H+

19

what enzyme results in the formation of the HETPP complex? need to know

pyruvate dehydrogenase

20

what enzyme transfers the acetyl group to the CoA from acetyl dihydrolipoamide? need to know

dihydrolipoyl transacetylase

21

which enzyme re-oxidises the dihydrolipoamide ? need to know

dihydrolipoyl dehydrogenase

22

the TCA cycle involves __ reactions.

A __ carbon unit (from acetyl Co A) condenses with a __ carbon unit. The resulting __ carbon unit is ______ twice

8 reactions

A 2 carbon unit (from acetyl Co A) condenses with a 4 carbon unit. The resulting 6 carbon unit is decarboxylated twice

23

the decarboxylation reactions in the TCA cycle form ____ as a byproduct

CO2 - so overall there are 2 CO2 formed

24

there are ___ oxidation reactions in the TCA which yield 3 ____ + ___ and 1 ____

there are 4 oxidation reactions in the TCA which yield 3 NADH + H and 1 FADH2§

25

what energy byproduct is formed in the TCA cycle?

GTP

26

what are the products of the TCA cycle : summary

2 CO2

3 NADH and H+

1 FADH2

1GTP

27

The TCA cycle:
1. OXALOACETATE (4 C) converted to ______ via ____ ____ (___ group added)
2. CITRATE converted to _____ via ______
3. ISOCITRATE converted to ______ via ____ _____ with the formation of ___ and ___ +___
4. Alpha - KETOGLUTARATE converted to ______ -__ via ______ ______ with the formation of ___ and ___ +___
5. SUCCINYL-COA converted to _____ via _____ with the formation of ___
6. SUCCINATE converted to ______ via ____ _____ with the formation of ___
7. FUMARATE converted to _____ via ______
8. MALATE converted to _____ via _____ _____ with the formation of ___

The TCA cycle:
1. OXALOACETATE (4 C) converted to CITRATE via CITRATE SYNTHASE (ACETYL group added)
2. CITRATE converted to ISOCITRATE via ACONITRASE
3. ISOCITRATE converted to ALPHA-KETOGLUTARATE via ISOCITRATE DEHYDROGENASE with the formation of CO2 and NADH + H+
4. Alpha - KETOGLUTARATE converted to SUCCINYL COA via ALPHA -KETOGLUTARE DEHYDROGENASE with the formation of CO2 and NADH + H+
5. SUCCINYL-COA converted to SUCCINATE via SUCCINYL-COA SYNTHASE with the formation of GTP
6. SUCCINATE converted to FUMARATE via SUCCINATE DEHYDROGENASE with the formation of FADH2
7. FUMARATE converted to MALATE via FUMARASE
8. MALATE converted to OXALOACETATE via MALATE DEHYDROGENASE with the formation of NADH + H+

28

All enzymes of the TCA cycle are located in the mitochondrial matrix, apart from:
____ ____-

SUCCINYL DEHYDROGENASE

29

what does succinate dehydrogenase do?

converts succinate and FAD to fumarate and FADH2

30

where is succinate dehydrogenase found?

in the inner mitochondrial membrane