carbohydrate metabolism glycolysis and the TCA

Question 1

what is an anabolic pathway

Answer 1

pathway concerned with the synthesis of cellular components

makes bonds

Question 2

what is a catabolic pathway

Answer 2

pathway that is involved with the degradation of cellular components
exergonic process which breaks bonds
increases entropy

Question 3

what is oxidation

Answer 3

loss of electrons
gain of oxygen
loss of hydrogen

Question 4

what is reduction

Answer 4

gain of electrons
loss of oxygen
gain of hydrogen

Question 5

where are the acid anhydride bonds located in ATP

Answer 5

they are located between the phosphate-oxygen-phosphate in the triphosphate molecule of ATP

Question 6

where are the phosphate ester bonds located in the ATP molecule

Answer 6

between the ribose oxygen and the phosphate of the triphosphate group

Question 7

why is ATP the currency of energy

Answer 7

due to its unstable energy rich nature of the acid anhydride bond

Question 8

why are the acid anhydride bonds full of energy

Answer 8

due to the charge repulsion because of the adjacent phosphate groups
and because of the resonance of phosphate ions

Question 9

which molecules have energy

Answer 9

sugar
starch
protein

Question 10

what is oxidation according to biochemical definitions

Answer 10

we can remove an electron and protons(H+ ions)

Question 11

what is TCA

Answer 11

tricarboxylic acid cycle/krebs cycle/citric acid cycle

Question 12

what is the most common fuel in mammals

Answer 12

glucose

Question 13

what is the only fuel the brain uses

Answer 13

glucose

Question 14

describe the structure of glucose

Answer 14

it is a 6 carbon sugar that has a tendency to remain in ring formation

Question 15

what occurs in glycolysis

Answer 15

glucose broken into 2 molecules of pyruvate

Question 16

what products are produced when glucose is fermented

Answer 16

ethanol
C02
lactate

Question 17

what products are produced when we have complete oxidation of glucose

Answer 17

6h20 and 2c02

Question 18

what are microbes called when they can survive in no oxygen

Answer 18

facultative anaerobes

Question 19

what do animals display

Answer 19

anerobiosis

Question 20

what is anaerobiosis

Answer 20

tolerate small amounts of anaerobic activity

Question 21

where does glycolysis occur

Answer 21

in the cytosol

Question 22

what are the two phases of glycolysis

Answer 22

the investment phase and the return phase

Question 23

what occurs in the investment phase of glycolysis

Answer 23

we use 2 molecules of ATP to produce fructose 1,6 bisphosphate

Question 24

what occurs in the return phase of glycolysis

Answer 24

we get some ATP BACK and pyruvate is produced

Question 25

how does glucose enter the cell

Answer 25

via transport proteins GLUT4

Question 26

what is the first stage of glycolysis

Answer 26

glucose enters the cell | glucose reacts with ATP- phosphorylated withe the enzyme hexokinase to produce glucose-6 phosphate

Question 27

why can glucose 6 phosphate not get out of the cell

Answer 27

because it is charged

Question 28

why can glucose 6 phosphate be broken down easily

Answer 28

due to the instability of the molecule due to the negative charge

Question 29

what conditions does hexokinase require

Answer 29

magnesium- type 2 and crowns disease can lack this

Question 30

which enzyme catalyses the isomerisation of G6P

Answer 30

phosphoglucose isomerase

Question 31

what is isomerism

Answer 31

the same empirical formula but a change in the shape

Question 32

what are the stages of isomerism of g6p

Answer 32

1. first the carbon 6 ring is opened- has an aldove 2. catalyse isomerisation occurs and the aldose is converted to a ketose 3. formation of the cyclic fructose 6 phosphate

Question 33

what then happens to fructose 6 phosphate

Answer 33

1. it reacts with ATP and phosphofructokinase(PFK) to produce fructose1,6 bisphosphate, ADP, H+ 2. this reacts with aldolase to produce glyceraldehyde 3 phosphate (gap) and dihydroxyacetone phosphate(DHAP)

Question 34

what is the rate determining step for glycolysis

Answer 34

the phosphorylation of fructose 6 phosphate to fructose 1,6 phosphate by phosphofructokinase

Question 35

what are the two products aldolase produces

Answer 35

GAP AND DHAP

Question 36

how do we convert dihydroxyacetone phosphate into glyceraldehyde 3 phosphate

Answer 36

by the enzyme triose phosphate isomerase which forms aldose and then forms glyceraldehyde 3 phosphate

Question 37

what is the ATP consuming summary

Answer 37

1. hexokinase 2. phosphoglucose isomerase 3. phosphofructosekinase 4. aldose 5. triose phosphate isomerase

Question 38

what does the second stage of glycolysis start with

Answer 38

glyceraldehyde 3 phosphate +NAD + pi and the enzyme glyceraldehyde 3 phosphate dehydrogenase to form 1,3bisphosphogltcerate + NADH+H+

Question 39

what molecule has a high phosphorylation transfer potential

Answer 39

1,3bisphosphogltcerate

Question 40

what happens to the 1,3 bisphosphogltcerate

Answer 40

reacts with ADP+H+ and phosphoglycerate kinase to from 3 phosphoglycerate and ATP

Question 41

what then happens to 3 phosphoglycerate

Answer 41

it reacts with phosphoglycerate mutate to form 2 phosphoglycerate

Question 42

what does 2 phosphoglycerate react with

Answer 42

endolase and a hydrolysis reaction to form ATP and pyruvate

Question 43

what can the reversible reaction of pyruvate form

Answer 43

phophophenolpyruvate (PEP) +ADP+H+

Question 44

which molecule must be regernated from the metabolism of pyruvate

Answer 44

NAD

Question 45

at the end of glycolysis what do we have

Answer 45

used 2 ATP molecules | created 4 ATP molecules THEREFORE net gain of 2ATP, 2PYRUVATE

Question 46

how can NAD be regenerated

Answer 46

1. pyruvate to lactate 2. pyruvate to acetylCoA 3. pyruvate to acetaldehyde-> ethanol which oxidises NADH

Question 47

how does pyruvate become acetyl coenzyme A

Answer 47

by the enzyme pyruvate dehydrogenase | and through oxidative decarboxylation

Question 48

where is acetylcoenzyme A found

Answer 48

in the matrix of the mitochondria

Question 49

what is the main role of the krebs cycle

Answer 49

to harvest high energy electrons from carbon compounds

Question 50

what is the first stage of the krebs cycle

Answer 50

citrate synthase

Question 51

how is citrate synthesised in the cycle

Answer 51

acetylcoA(2C) enters and is condensed and reacts with oxaloacetate(4C) to form citrate COA and then the coA leaves the molecule to form citrate(6C)

Question 52

what is the second stage of the krebs cycle

Answer 52

citrate first undergoes dehydration, then isomerisation to form cis citrate and then hydration again to form isocitrate. aconitase reacts in both steps

Question 53

what is the third stage of the krebs cycle

Answer 53

isocitrate(6C) undergoes oxidative decarboxylation which forms alpha ketoglutarate(5C) with the help of the enzyme isocitrate dehydrogenase ALSO RELEASES NADH

Question 54

what is the rate determining step of the krebs cycle

Answer 54

the overall formation of a ketoglucarate

Question 55

WHAT IS STAGE 4 OF THE KREBS CYCLE

Answer 55

oxidative decarboxylation from a ketoglutarate(5C) to succinylCOA(4C) RELEASES NADH

Question 56

what is step 5 of the krebs cycle

Answer 56

substrate level phosphorylation from Succinyl COA to succinate this forms ATP with the help of the enzyme succinylCOA synthase

Question 57

what is step 6 of the krebs cycle

Answer 57

dehydrogenation/oxidation from succinate(4C) to fumarate (4C) releasing FADH2

Question 58

what is step 7 of the krebs cycle

Answer 58

hydration of fumarate to malate by fumerase

Question 59

what is step 8 of the krebs cycle

Answer 59

dehydrogenation/oxidation from malate to oxaloacetate with malate dehydrogenase RELEASING NADPH

Question 60

which step of the krebs cycle is irreversible

Answer 60

1,3,4