metabolism

Question 1

define metabolism

Answer 1

the sum of all chemical reactions occuring in an organism

Question 2

what are anabolic pathways responsible for

Answer 2

assembling simple molecules into complex ones, requiring energy

Question 3

what are catabolic pathways responsible for

Answer 3

breakdown of complex molecules into simple ones, releasing energy

Question 4

what is the first law of thermodynamics

Answer 4

total energy input must equal energy output

Question 5

what are the 2 main energy output types

Answer 5

somatic and maturity maintenance

Question 6

what is energy used for in somatic maintenance

Answer 6

existence e.g. growth

Question 7

what is energy used for in maturity maintenance

Answer 7

reproduction

Question 8

what controls the appetite and satiety centres

Answer 8

arcuate nucleus (ARC)

Question 9

what are the appetite suppressors and stimulators

Answer 9

NPY - stimulator
MSHs - suppressor

Question 10

what controls mid / long term energy balance

Answer 10

leptin (fat storage) and insulin inhibit NPY release

Question 11

what controls short term energy balance (3)

Answer 11

CCK intestinal secretion signals satiety
PPY (intestine) inhibit NPY
Ghrelin (stomach) stimulates NPY

Question 12

what is basal metabolic rate (BMR)

Answer 12

stable rate of energy metabolism in endothermic animals under minimal environmental and physiological stress

Question 13

what is standard metabolic rate (SMR)

Answer 13

an ectotherms resting metabolic rate at a given body temperature

Question 14

what is aerobic metabolic scope

Answer 14

the metabolic range of which an animal is capable. The ratio of maximum sustainable metabolic rate (MMR) to BMR / SMR

Question 15

2 ways to measure metabolic rate and how do they do it

Answer 15

direct calorimetry - measure heat change
respirometry - measures oxygen in and carbon dioxide out

Question 16

what is the issue with how we measure metabolic rate

Answer 16

they assume energy generated = oxygen used but different fuels liberate different amounts of energy

Question 17

what is the equation for the respiratory quotient

Answer 17

Rq = rate of CO2 production / rate of O2 consumption

Question 18

what is the respiratory quotient for:
2C51H98O6 + 145O2 -> 102CO2 + 98H2O

Answer 18

145 / 102 = 0.7

Question 19

what is the Rq for carbohydrates

Answer 19

1

Question 20

what is the Rq for fats

Answer 20

0.7

Question 21

what is the Rq for proteins (usually)

Answer 21

0.8

Question 22

list 6 things that can effect energetic demands / metabolic rate

Answer 22

size and mode of thermo-regulation
locomotion
development
reproduction
circadian rhythm
stress

Question 23

how does locomotion impact metabolic rate - small vs large animals

Answer 23

larger animals have lower overall cost of transport per gram of body mass due to inertia

Question 24

how does reproduction impact metabolic rate

Answer 24

K selected species require more energy per offspring

Question 25

how does Briceno’s paper support circadian rhythms impacting metabolic rate

Answer 25

nocturnal lobsters have higher metabolic rate at night

Question 26

How does Briceno’s paper show stress impacting metabolic rate

Answer 26

lobsters exposed to karimone (squid which would eat lobster)
those exposed to stressor decrease metabolic rate as they are hiding

Question 27

what happened when temperature was increased in the lobster experiment

Answer 27

energetic trade-off’s - the lobsters didn’t hide as they could not afford to. They had higher energetic demands so needed to continue eating despite threat

Question 28

what happens to oxygen conc in ectotherms as temperature increases

Answer 28

oxygen conc. increases until proteins are denatured

Question 29

what happens as temperature increases in endotherms

Answer 29

it controls it’s own temperature as long as conditions stay on the euthermic zone
outside the ranges of the euthermic zone the organism doesn’t function