Carbohydrates (Lecture 1)

Question 1

what is metabolism?

Answer 1

process by which living organisms acquire and utilize the free energy they need in order to carry out various functions

Question 2

what is catabolism?

Answer 2

degradation

constituents are broken down to salvage their components and generate free energy

Question 3

what is anabolism?

Answer 3

biomolecules are synthesized from simpler components

Question 4

standard metabolic rate

Answer 4

metabolic rate of an organism not digesting food, at therm-neutrality, under resting conditions and under stress free conditions

Question 5

what are house keeping activities?

Answer 5

transcription
translation
protein folding 
vesicular transport 
membrane transport

Question 6

negative energy balance implies that _____ and can result in _____.

Answer 6

more energy expenditure than energy intake

can lead to anorexia, cachexia and death

Question 7

positive energy balance implies that _____ and can result in _____.

Answer 7

more energy intake than energy expenditure

weight gain, obesity, type 2 diabetes and death

Question 8

metabolic pathways are (5)

Answer 8

irreversible

have a first committing step

are regulated

catabolic and anabolic pathways must doffer

occur in specific locations in the eukaryotic cells

Question 9

what does a highly exergonic reaction provide to a multistep metabolic pathway?

Answer 9

it makes the entire pathway irreversible, thus providing directionality

Question 10

what is a committing step?

Answer 10

an irreversible reaction that commits the intermediate it produces to continue down the pathway

Question 11

all metabolic pathway are regulated by ___

Answer 11

the laws of supply and demand

Question 12

how is control exerted on the flux of metabolites in a metabolic pathway?

Answer 12

regulate the rate limiting step

Question 13

allosteric regualtion

Answer 13

retro inhibition, where the produce control the activity of the enzyme

if there is a surplus of the product, then the enzyme promoting synthesis is inhibited

Question 14

covalent modification

Answer 14

enzyme can be inactivated or activated by phosphorylation/ dephosphorylation via a kinase/phsophatase

Question 15

substrate cycles

Answer 15

must activate one side of the cycle to initiate a catabolic reaction and shut down the other side to inhibit the anabolic reaction

Question 16

genetic control

Answer 16

to upregulate a certain outcome, an upregulaton of the production of an enzyme via an increased in transcription and translation.

Question 17

why do metabolic reactions occur in specific locations of the cell?

Answer 17

separate the processes to allow for control over the conditions the reaction is subjected to

regulation of a certain pathway will be compartmentalized in to one location of the cell to result in an increased efficiency, since all of the necessary reactants/enzymes are close by

Question 18

Gibs free energy is an indicator of____

Answer 18

Spontaneity

Question 19

delta Go indicates the ______ of the reaction

Answer 19

nature (endergonic/exergonic)

Question 20

delta Go > 0

Answer 20

endergonic, requires energy input

Question 21

delta Go < 0

Answer 21

exergonic, produces energy

Question 22

delta G indicates _______ of a reaction

Answer 22

the direction and the likely hood of ir/reversibility in vivo

Question 23

delta G =0

Answer 23

reaction is in equilibrium, reversible in vivo

Question 24

delta G > 0

Answer 24

not spontaneous in vivo, require free energy

Question 25

delta G < 0

Answer 25

spontaneous in vivo, processes that can be utilized to do work, as for they produce energy

Question 26

coupling

Answer 26

coupling of an endergonic reaction to an exergonic reaction will make the overall reaction favourable in vivo

this is because the energy required to allow the endergonic reaction to proceed is supplied by the free energy produced by the exergonic reaction