bioenergetics and exercise metabolism - week 2

Question 1

what is bioenergetics ?

Answer 1

flow and exchange of energy within a living system

Question 2

what is metabolism ?

Answer 2

sum of all chemical reactions that occur int he body

Question 3

what’s an anabolic reaction?

Answer 3

synthesis of molecules

Question 4

what is a catabolic reaction?

Answer 4

breakdown of molecules

Question 5

what is an endergonic reaction ?

Answer 5

requires energy to be added to the reactants

Question 6

what’s an exergonic reaction?

Answer 6

releases energy

Question 7

what’s a coupled reaction?

Answer 7

liberation of energy in an exergonic reaction drives an endergonic reaction

(release of energy provides energy for another reaction)

Question 8

what is oxidation-reduction reactions ?

Answer 8

coupled reactions

oxidation - removes an electron

reduction - gains an electron

Question 9

how does FAD and NAD play roles in oxidation and reduction ?

Answer 9

they act as carrier molecules

help with transfer of H+ in the electron transport chain

Question 10

what is an enzyme ?

Answer 10

proteins that lower the activation energy and accelerate chemical reaction

Question 11

what is meant by kinase ?

Answer 11

adding of a phosphate group

Question 12

what is meant by dehydrogenase ?

Answer 12

remove hydrogen atoms

Question 13

what’s meant by oxidases ?

Answer 13

catalyses oxidation

reduction reactions involving oxygen

Question 14

what’s meant by isomerases ?

Answer 14

rearrangement of the structure of molecules

Question 15

how does anaerobic pathways help form ATP (2)

Answer 15

doesn’t involve oxygen

phosphocreatine breakdown + glycolysis

Question 16

how do aerobic pathways help form ATP? (2)

Answer 16

require oxygen

oxidative phosphorylation

depend on respiratory and CV system to deliver O2

Question 17

what is the ATP-PC system ? (3)

Answer 17

most rapid method of producing ATP

phosphocreatine breakdown

deplete after 10-15 secs

PC+ADP&raquo_space; ATP+C

Question 18

what is glycolysis ?

Answer 18

30-90 seconds

glycolic pathway

produce 2 NADH, 2 pyruvate or 2 lactate

Question 19

for chemical reactions in ___ to continue, adequate amounts of __ must be available to accept __

Answer 19

glycolysis

NAD+

H+

Question 20

how can NAD+ rapidly reform from NADH ? (2)

Answer 20

sufficient O2: H+ shuttled to mitochondria

insufficient O2: pyruvate can accept H+ to form lactate
- lactate formation allows recycling of NAAD+ so glycolysis can continue without O2

Question 21

how does the citric acid cycle produce ATP ? (4)

Answer 21

pyruvate enters mitochondria and converted to acetyl CoA + makes CO2

acetyl CoA combines with oxaloacetate to form citrate, generates 2CO2

each cycle released 3NADH and FADH2

provides electrons for electron transport chain

Question 22

how does the electron transport chain work ? (4)

Answer 22

NADH and FAD are reoxidised from H+

electrons are passed down electrons carries (cytochromes) and pumping of H+ into inter membrane space

movement of H+ through ATP synthase produces ATP

O2 accepts the H+ passed along making H2O

Question 23

what is the total ATP produces from 1 glucose molecule ?

Answer 23

known as 32 molecules

historically it is 38 molecules

Question 24

what is an oxygen deficit ?

Answer 24

discrepancy between initial demand/atp production and oxygen consumption

Question 25

why do trained individuals have lower O2 deficit than untrained ? (3)

Answer 25

better developed bioenergetic capacity :

• greater regional blood flow to active muscle
• increased cellular adaptation efficiency
• increased mitochondrial volume in fibres reduces lactate production at start of exercise

Question 26

what is EPOC ? and what is it most influenced by ? (2)

Answer 26

excess post-exercise oxygen consumption

magnitude and duration of EPOC influenced by intensity of exercise

Question 27

what is the rapid portion of EPOC ?

Answer 27

resynthesis of stored PC in muscles (60-120s)

replenish muscle and blood O2 stores

Question 28

what is the slow portion of EPOC?

Answer 28

evaluated HR and breathing increase O2 demand

elevated body temp increases metabolism

elevated blood levels of epinephrine + norepinephrine = increased metabolic rate

Question 29

what is conversion of lactic acid to glucose?

Answer 29

gluconeogenesis

Question 30

what metabolic response is used for short term high intensity exercise <5secs?

Answer 30

ATP from ATP-PC

Question 31

what metabolic response is used for intense exercise > 5 secs ?

Answer 31

shift to ATP production via glycolysis

Question 32

what metabolic response is used in events lasting more than 45 secs ?

Answer 32

ATP-PC, glycolysis and aerobic systems

50/50 aerobic and anaerobic

Question 33

what metabolic response occurs in prolonged exercise over 10 mins ?

Answer 33

ATP primarily from aerobic metabolism