Biochemistry Carbohydrates

Front 1

What is normal blood glucose concentration?

Back 1

5mM

Front 2

Which tissues are GLUT1 and GLUT3 found on? What are their Kms?

Back 2

Brain, RBCs; 1-2mM

Front 3

Which tissues is GLUT2 found on?
What is GLUT2's Km?

Back 3

liver; 12mM

Front 4

Which tissues is GLUT4 found on?
What is its Km?

Back 4

muscle, adipose tissue; 5mM

Front 5

Which GLUT transporter is dependent on a hormone? Name the hormone.

Back 5

GLUT 4; insulin

Front 6

What is the function of glycolysis?

Back 6

To convert glucose to pyruvate to use for producing ATP.

Front 7

In anaerobic glycolysis, what is pyruvate converted to?

Back 7

Lactate

Front 8

In aerobic glycolysis, what is pyruvate converted to?

Back 8

Acetyl CoA

Front 9

What are the three rate limiting enzymes of glycolysis?

Back 9

hexokinase, PFK1, pyruvate kinase

Front 10

Instead of hexokinase, what enzyme is in the liver?

Back 10

Glucokinase

Front 11

What inhibits hexokinase?

Back 11

glucose6P

Front 12

What inhibits PFK1?

Back 12

ATP, citrate, H+

Front 13

What stimulates PFK1?

Back 13

fructose-2,6-bisP

Front 14

what inhibits pyruvate kinase?

Back 14

ATP, alanine, glucagon

Front 15

What stimulates pyruvate kinase?

Back 15

fructose-1,6-bisP

Front 16

Apart from regulatory enzymes, what else regulates glycolysis?

Back 16

substrate availability (diet) = glucose, NAD+; product removal (NADH and H+ recycling to NAD+)

Front 17

Which enzyme in involved in converting pyruvate to lactate?

Back 17

lactate dehydrogenase

Front 18

which enzyme is involved in converting Pyruvate to Acetyl CoA?

Back 18

pyruvate dehydrogenase

Front 19

What two enzymes regulate the activity of pyruvate dehydrogenase?

Back 19

pyruvate dehydrogenase kinase and pyruvate dehydrogenase phosphatase.

Front 20

Is pyruvate dehydrogenase active is the dephosphorylated or phosphorylated form?

Back 20

dephosphorylated

Front 21

What regulates the activity of pyruvate dehydrogenase kinase?

Back 21

Ratios of ATP/ADP, Acetyl CoA/CoA and NADH+H+/NAD+

Front 22

what regulates the activity of pyruvate dehydrogenase phosphatase?

Back 22

Ca2+ (musc. contraction), insulin

Front 23

What are the names of the shuttles?

Back 23

glycerophosphate shuttle (FADH2 linked), malate/aspartate shuttle (NADH linked).

Front 24

What are the functions of the shuttles?

Back 24

transfer NADH or FADH2 across the mitochondrial membranes.

Front 25

what is the function of gluconeogenesis?

Back 25

To synthesise glucose from non-carbohydrate precusors

Front 26

What are precursors of gluconeogenesis?

Back 26

lactate, glycerol and gluconeogenic amino acids. (propionate in ruminants)

Front 27

What are the 4 enzymes in the obligatory quartet of gluconeogenesis?

Back 27

pyruvate carboxlase, PEP carboxy kinase, fructose-1,6-bisPhosphatase, glucose-6-Phosphatase

Front 28

what does pyruvate carboxylase do?

Back 28

convert pyruvate to OAA.

Front 29

what does PEP carboxy kinase do?

Back 29

converts OAA to PEP

Front 30

what does fructose-1,6-bisPhosphatase do?

Back 30

converts fructose-1,6-bisP to fructose-6P

Front 31

what does glucose-6Phosphatase do?

Back 31

converts glucose6P to glucose.

Front 32

what is the rate limiting step of gluconeogenesis?

Back 32

fructose-1,6-bisPase

Front 33

Which hormone stimulates the synthesis of PEP carboxy kinase?

Back 33

glucagon

Front 34

Which hormone stimulates the synthesis of glycolytic enzymes?

Back 34

insulin

Front 35

What does fructose-2,6-bisP do to glycolysis and gluconeogenesis?

Back 35

stimulates glycolysis, inhibits gluconeogenesis.

Front 36

What processes maintain glucose homeostasis when just fed? And which hormone drives these?

Back 36

glycogenesis (excess glucose as glycogen), storing excess carbon as fat). Driven by insulin.

Front 37

What processes maintain glucose homeostasis when starving? Which hormone drives these?

Back 37

short term - glycogenolysis =liver mobilises glycogen stores.
mid-term - spare glucose, muscle use fat, gluconeogenesis. Driven by glucagon.

Front 38

What processes maintain glucose homeostasis when under stress or during exercise? Which hormone drives these?

Back 38

maximise glucose availability
glycolysis
Driven by glucagon.

Front 39

What is the function of glycogenesis?

Back 39

To store excess glucose until needed.

Front 40

Which enzymes are involved in glycogenesis?

Back 40

phosphoglucomutase, glycogen synthase.

Front 41

What are the glycogen stores in liver and muscle used for?

Back 41

liver - glucose homeostasis (short term)
muscle - ATP for contraction

Front 42

Which hormone activates glycogen synthase?

Back 42

insulin

Front 43

which enzymes are involved in glycogenolysis?

Back 43

glycogen phosphorylase, phosphoglucomutase

Front 44

What inhibits glycogenolysis?
What stimulates glycogenolysis?

Back 44

insulin inhibits, glucagon and adrenalin stimulate, as does muscle contraction.

Front 45

What inhibits glycogenesis?
what stimulates glycogenesis?

Back 45

Adrenalin and glucagon inhibit glycogenolysis. Insulin stimulates glycogenesis.

Front 46

What is the function of the Pentose Phosphate Pathway?

Back 46

to produce NADPH (reducing power) for fatty acid synthesis and steroid hormone production, and to provide ribose-5-P for nucleotide synthesis.

Front 47

What does the oxidative phase of the pentose phosphate pathway generate?

Back 47

NADPH

Front 48

What does the non-oxidative phase of the pentose phosphate pathway generate?

Back 48

ribose-5-P