Topic 2 General

Question 1

Monosacharrides

Answer 1

Glucose, galactose, fructose
absorbed immediately in the mouth

Question 2

Polysaccharides

Answer 2

Starch cellulose
Salivary Amylase breaksdown in mouth then further broken down by stomach amylase

Question 3

small intestine

Answer 3

Pancreatic amyalse
breaks down strach into oligosacchradies

Question 4

Dissacharides

Answer 4

Lactose, maltose, sucrose
broken down by brush-border enzymes
ie dextrinase

Question 5

Celluose

Answer 5

Is fibre
doesn’t get broken down

Question 6

Sucrose

Answer 6

galactose and frucotse

Question 7

Lactose

Answer 7

Galactose and glucose

Question 8

Glycolysis

Answer 8

Universal central pathway of catabolic metabolism

Question 9

In Glycolysis - 1 glucose molecule =

Answer 9

2 ATP and 2 pyruvate

Question 10

Energy investment phase

Answer 10

first 5 steps of glycolysis

Question 11

Energy production phase

Answer 11

Last 5 steps of glycolysis

Question 12

NADH

Answer 12

is the reducing agent

Question 13

Regulatory step 1

Answer 13

Hexokinase - Build up of G6P inhibits hexokinase
i.e - we already have enough stop making more

Question 14

Regultory step 2

Answer 14

in step 3
phosphofrucokinase is inhibited by ATP but also accerlerated by AMP and ADP

Question 15

Regulatory step 3

Answer 15

in step 10
Pyruvate kinase inhibited by high ATP but activated by high fructose1,6bisphosphate

Question 16

Glycolysis reaction

Answer 16

Glucose +2 ADP +2Pi +2NAD = 2 ATP + 2 Pyruvate + NADH +2H +2H2O

Question 17

NADH aerobic conditions

Answer 17

will be reoxidesed back to NAD+

Question 18

NADH anaerobic conditions

Answer 18

reoxidised via the conversion of pyruvate to lactic acid or ethanol

Question 19

Fates of pyruvate

Answer 19

Lactic acid
Acetyl CoA
Alanine
Oxaloacetate
Ethanol
which way it goes depends on if there is o2 present or not to reoxidise the NADH

Question 20

Pyruvate to lactate

Answer 20

Under anabolic conditions
generally when exercising
pyruvate is reduced to lactate and the electron that is added came from NADH - hence why it becomes more acedic
pyruvate ———— lactate
enzyme - lactate dehydrogenase

Question 21

Pyruvate to ethanol

Answer 21

Pyruvate ————— acteylaldhyde
enzyme = pyruvate decarboxylase

acetaldehyde ————– ethanol
alcohol dehydrogenase
the reduced H from NADH is added to the acetaldehyde

Question 22

Regulation of Phosphofructokinase (pfk1)

Answer 22

Activated by low ATP , ADP High levels of f16bp
Inhibitors Citrate and ATP
High level of atp lowers affinity for f16bp
High levels of citrate also lowers affinity

Question 23

Regulation of pyruvate kinase

Answer 23

activated by F16BP, ADP, AMP
inhibited by ATP, fatty acid

Question 24

Entry of other sugars

Answer 24

HExokinase also has affinity for other sugars

Question 25

entry of galactose

Answer 25

1) galactose to galacotse-1-phophate (phosphorylated) by galactose kinase
2) glactose-1phophate to glucose-1-phospahte, using UDP glucose, enzyme is UDP-glucose-d-galctose-1-phopshate uridyltransferase
3) glucose-1-phopshate to g6p - enzyme is phosphoglucomutase

Question 26

Entry of fructose

Answer 26

Frucotse to fructose-1-phosphate, enzyme is fructokinase
f1p to DHAP and G3P, via enzyme aldolase b
then enters as normal

Question 27

Entry of mannose

Answer 27

mannose to mannose 6 phosphate via enzyme mannose kinase
m6p to f6p via phosphomannoisomerase

Question 28

entry of dissachrides

Answer 28

Hydrolysis to the monomer, then the monomer follows their individual routes