module 5 - 18.1 glycolysis & 18.2 linking glycolysis and the Krebs cycle

Question 1

what do cells require energy for?

Answer 1

• synthesis of molecule
• transport of molecules or ions
• cellular movement

Question 2

what is ATP?

Answer 2

the intermediary between energy-yielding and energy-requiring cellular reactions

Question 3

what is MRS NERG?

Answer 3

M - movement
R - respiration
S - secretion
N - nutrition
E - excretion
R - reproduction
G - growth

Question 4

what is respiration?

Answer 4

making ATP from glucose

Question 5

how des ATP function as the universal energy currency?

Answer 5

• energy is required to break bonds
• energy is released when bonds are broken
• ATP + H2O ⇌ ADP + Pi
• living cells maintain the ratio of ATP to ADP with conc. five-fold higher than conc. of ADP
• phosphate to phosphate bonds are high energy bonds

Question 6

what is released from ATP + H2O ⇌ ADP + Pi?

Answer 6

30.6kJmol-1

Question 7

what is PI?

Answer 7

an inorganic phosphate

Question 8

what is glucose?

Answer 8

a respiratory substrate

Question 9

where does glucose have energy stored?

Answer 9

in its carbon to carbon and carbon to hydrogen bonds

Question 10

how is the energy from glucose transferred to ATP?

Answer 10

by cellular respiration

Question 11

what is chemiosmosis?

Answer 11

when glucose molecules are broken down in stages and the released energy is used to convert ADP and Pi to ATP

Question 12

what is cellular respiration?

Answer 12

a multi-step and multi-stage process and each reaction is controlled by an enzyme

Question 13

what is aerobic respiration?

Answer 13

with free oxygen

Question 14

what is glycolysis and where does glycolysis occur?

Answer 14

• first stage of cellular respiration
• cytoplasm (mitochondria not involved)

Question 15

what happens during glycolysis?

Answer 15

1. 2 ATPs are consumed to phosphorylate glucose into hexose bisphosphate
2. hexose bisphosphate is split into 2 molecules of triose phosphate
3. each triose phosphate has a phosphate added to it using Pi from cytoplasm to make triose bisphosphate
   4a) the 2 triose bisphosphates are oxidised by removal of hydrogen (dehydrogenation) and forms 2 pyruvate. hydrogen atoms are accepted by NAD to form reduced NAD
   4b) the 2 triose bisphosphate molecules have their phosphate groups removed, they’re used to reform ATP from ADP (substrate level phosphorylation)

Question 16

what is the net production of ATP molecules for every glucose?

Answer 16

2 ATP molecules which isnt enough so cant survive on anaerobic respiration alone

Question 17

what do phosphates do?

Answer 17

lower the activation energy

Question 18

which has a lower activation energy: triose bisphosphate or glucose?

Answer 18

triose bisphosphate

Question 19

what happens in the matrix?

Answer 19

contains enzymes for the Krebs cycle and the link reaction
- also contains mitochondrial DNA

Question 20

what happens in the outer mitochondrial membrane?

Answer 20

separates contents of mitochondrion from the rest of the cell, creating cellular compartment with ideal conditions for aerobic respiration

Question 21

what happens in the inner mitochondrial membrane?

Answer 21

contains elctron transport chains and ATP synthase

Question 22

what are cristae?

Answer 22

projections of the inner membrane which increase the surface area available for oxidative phosphorylation

Question 23

what is the intermembrane space?

Answer 23

proteins are pumped into this by electron transport chain
- small space to conc. builds up quickly

Question 24

why is the membrane of the mitochondria folded?

Answer 24

• larger SA
• packs more enzymes

Question 25

what is a link reaction?

Answer 25

links glycolysis to krebs cycle

Question 26

what happens during the link reaction/oxidative decarboxylation?

Answer 26

1. pyruvate pumped into matrix by carrier proteins
2. pyruvate is put through oxidative decarboxylation
3. carbon dioxide is removed by oxidation reaction
4. hydrogen atoms are accepted by NAD to produce reduced NAD (reduction)
5. this produced a 2-carbon group tat gets bound to coenzyme A to produce acetyl CoA

Question 27

how is ATP used to help pyruvate?

Answer 27

ATP is used to pump pyruvate against a concentration gradient from cytoplasm so has carrier proteins in mitochondrial membrane