metabolic pathways

Question 1

what are the two versions of interconversion in the body?

Answer 1

catabolism-break down food to release energy

anabolism-build useful macromolecules

Question 2

what is endergonic and exergonic?

Answer 2

endergonic- requires energy

exergonic- energy releasing

Question 3

what is important in metabolism?

Answer 3

energy- released from some molecules and is needed to build others

carbon skeletons-building blocks for many different types of molecules

reducing equivalents- electrons are needed for other reactions :NADH, NADPH, FADH2

Question 4

whats the most common type of reaction in food breakdown?

Answer 4

oxidation

Question 5

what are metabolic pathways?

Answer 5

they are pathways responsible for breaking down compounds to release energy is done in steps helped by enzymes

Question 6

what types of of metabolic pathways are there?

Answer 6

• linear pathways
• branched pathways
• cyclic pathways
• repeating (spiral) pathways

Question 7

what happens in a cyclic catabolic pathway?

Answer 7

The product is broken down on a carrier molecule

that is unchanged at the end

Question 8

what happens in a cyclic biosynthetic pathway?

Answer 8

the product is built up on a carrier molecule that is unchanged at the end

Question 9

what happens in repeating pathways?

Answer 9

the substrate undergoes a series of reactions resulting in a similar product but 2 carbons longer/ shorter, this undergoes the same sequence of reactions

Question 10

what are some general principles of metabolism?

Answer 10

• the flow through metabolic pathways is unidirectional and irreversible
• the first step in the pathway is always the rate limiting step
• flow through pathways is regulated

Question 11

what are the 5 circulating fuels in metabolism?

Answer 11

• glucose
• amino acids
• free fatty acids
• lactate
• ketone bodies

Question 12

what are the 3 energy storage forms in cells?

Answer 12

glycogen
protein
triglycerides

Question 13

how does AMP work as a regulator?

Answer 13

[ATP]+[ADP]+[AMP]=constant concentration
[ATP]>[ADP]>[AMP]
salvaging ATP in low energy state, hence AMP is the signal for low energy state

Question 14

how are enzyme pathways regulated?

Answer 14

by gene regulation. the cell switches on/ off the genes that code for specific enzymes

Question 15

how does inhibition work in feedback regulation?

Answer 15

• negative feedback

- the end-product of a pathway turns off an enzyme earlier in the pathway to prevent the cell wasting chemical resources

Question 16

how does activation work in feedback regulation?

Answer 16

• positive feedback
• the end-product speeds up production of further product
• rapid and efficient response

Question 17

what is the allosteric regulation of enzymes?

Answer 17

• it is when a regulatory molecule binds to a protein at one site and affects the proteins function at another site
• it may inhibit or activate pathways by stabilizing the active or inactive version of the enzyme

Question 18

what is cooperativity?

Answer 18

its a form of allosteric regulation
a substance primes an enzyme to act on additional substrate molecules more readily
its allosteric as binding in one active site affects substrate binding in another active site