week 1- Carbohydrate and metabolism

Question 1

what is catabolism

Answer 1

processes in which complex substances are degraded to simpler molecules

Question 2

what is anabolism

Answer 2

processes concerned primarily with the synthesis of complex organic molecules

Question 3

what is catabolism associated with

Answer 3

net release of chemical energy

Question 4

what is anabolism associated with

Answer 4

net input of energy required

Question 5

what is glycolysis

Answer 5

releasing energy from glucose

Question 6

what is gluconeogenesis

Answer 6

process in which body maintains glucose levels from non-carbohydrate sources (reverse glycolysis)

Question 7

what is the 6th step of glycolysis

Answer 7

GADPH reduces NAD+ to NADH

Question 8

why is NADH re oxidised

Answer 8

because cytoplasm has a finite supply of NAD+

Question 9

what is a fermentation

Answer 9

an energy-yielding metabolic pathway with no net change in the oxidation state of products compared to substrates

Question 10

where does homolactic fermentation occur

Answer 10

animal cells, and lactic acid bacteria

Question 11

where does alcoholic fermentation occur

Answer 11

in yeast

Question 12

what does anaerobic glycolysis lead to

Answer 12

pyruvate

Question 13

what happens to pyruvate produced in anaerobic glycolysis

Answer 13

it is reduced, so no net oxidation of glucose occurs

Question 14

what is lactate formed by

Answer 14

active skeletal muscle

Question 15

what are the primary gluconeogenic tissues?

Answer 15

liver and the kidney cortex

Question 16

when does the body make glucose

Answer 16

1. long periods in the absence of carbohydrates
2. intense exercise

Question 17

what does gluconeogenesis use to bypass irreversible reactions of glycolysis

Answer 17

enzymes

Question 18

which enzymes does gluconeogenesis use to bypass the conversion of pyruvate to phosphoenol-pyruvate

Answer 18

1. pyruvate carboxylase
2. phosphoenolpyruvate carboxykinase

Question 19

what is pyruvate converted to by pyruvate carboxylase

Answer 19

oxaloacetate

Question 20

what is oxaloacetate converted to by phosphoenolpyruvate carboxykinase

Answer 20

phosphoenol-pyruvate

Question 21

what reaction converts fructose-1,6-bisphosphate to fructose-6-phosphate

Answer 21

hydrolytic reaction catalysed by fructose-1,6-bisphosphatase

Question 22

what non-carbohydrate precursors can glucose be synthesises by

Answer 22

Amino acids
Glycerol
Lactate

Question 23

what does the hydrolysis of triacylglycerol yield

Answer 23

glycerol and fatty acids

Question 24

can animals convert fatty acids into glucose

Answer 24

no

Question 25

what mechanism is involved in the synthesis of glucose from lactate

Answer 25

the cori cycle

Question 26

what is the cori cycle

Answer 26

Lactate produced in glycolysis during muscle exertion is transported to the liver, for resynthesis of glucose by gluconeogenesis. Transport of glucose back to muscle for synthesis of glycogen, and its reutilization in glycolysis, completes the cycle.

Question 27

how is glycolysis and gluconeogenesis regulated

Answer 27

reciprocally

Question 28

what is glycolysis determined by

Answer 28

glucose availibility

Question 29

what is gluconeogenesis determined by

Answer 29

precursor availability

Question 30

what are the enzymes involved in the regulation of glycolysis and gluconeogenesis

Answer 30

phosphofructokinase fructose-1,6-bisphosphatase pyruvate kinase pyruvate carboxylase phosphoenolpyruvate carboxykinase

Question 31

what is phosphofructokinase stimulated and activated by

Answer 31

stimulated by high levels of AMP activated by fructose-1,6-bisphosphate

Question 32

what is phosphofructokinase inhibited by

Answer 32

high levels of ATP and citrate

Question 33

what is Fructose-1,6-Bisphosphatase stimulated by

Answer 33

high levels of citrate

Question 34

what is Fructose-1,6-Bisphosphatase inhibited by

Answer 34

high levels of AMP and Fructose-2,6-Bisphosphate

Question 35

what is pyruvate kinase activated by

Answer 35

Fructose-1,6-Bisphosphate

Question 36

what is pyruvate kinase inhibited by

Answer 36

high levels of ATP and alanine

Question 37

what is pyruvate carboxylase activated by

Answer 37

high levels of acetyl-CoA

Question 38

what is carboxylase inhibited by

Answer 38

high levels of ADP

Question 39

what is Phosphoenolpyruvate carboxykinase (PEPCK)

Answer 39

high levels of ADP

Question 40

which state is insulin released in

Answer 40

when there are high blood sugar levels (the fed state)

Question 41

what does insulin stimulate

Answer 41

expression of genes encoding the proteins of glycolysis

Question 42

what does insulin inhibit

Answer 42

glyconeogenesis by switching off expression of Phosphoenolpyruvate carboxykinase

Question 43

what does glucagon stimulate

Answer 43

glyconeogenesis by switching on expression of phosphoenolpyruvate carboxykinase & Fructose 1,6, Bisphosphatase

Question 44

what does glucagon inhibit

Answer 44

expression of genes encoding the proteins of glycolysis