Metabolism Review

Question 1

All chemical reactions of a cell/organism

Answer 1

Metabolism

Question 2

Series of biochemical reactions that convert >1 substrate into a final product

Answer 2

Metabolic Pathway

Question 3

Pathway requiring energy to synthesize larger molecules

Answer 3

Anabolic

Question 4

Pathway requiring energy to synthesize larger molecules

Answer 4

Anabolic

Question 5

Pathway that releases energy and breaks down large molecules into small ones

Answer 5

Catabolic

Question 6

Ability to do work

Answer 6

Energy

Question 7

Total amount of energy in the universe is constant; energy cannot be created/destroyed

Answer 7

First Law of Thermodynamics

Question 8

Within each chem. reaction, some energy is lost in a form that is unusable. This results in increased entropy

Answer 8

Second Law of Thermodynamics

Question 9

Amount of energy available to do work (usable energy)

Answer 9

Gibb’s Free Energy

Question 10

Energy is released in a chem. reaction (delta G < 0); products of these reactions have less free energy than substrates

Answer 10

Exergonic Reaction

Question 11

Chem. reaction requires input of energy (delta G > 0); products have more free energy than substrates

Answer 11

Endergonic Reaction

Question 12

What is the main source for activation energy in a cell?

Answer 12

Heat energy

Question 13

Is ATP hydrolysis reversible?

Answer 13

Yes

Question 14

What energy does the sodium potassium pump use?

Answer 14

Energy from exergonic ATP hydrolysis

Question 15

How many sodium ions exit the cell in the NaK+ pump?

Answer 15

3

Question 16

How many potassium ions enter the cell in the NaK+ pump?

Answer 16

2

Question 17

Catalyst

Answer 17

Increases the rate of a reaction without being consumed

Question 18

Why do cellular reactions need catalysts?

Answer 18

Activation energies are too high for heat energy from the surroundings to overcome

Question 19

Protein catalysts that bind with reactant molecules to promote chemical processes; very specific and can only catalyse a single reaction

Answer 19

Enzyme

Question 20

What is an example of a non-protein enzyme?

Answer 20

Ribosomes

Question 21

Chemical reactants to which an enzyme binds

Answer 21

Substrate

Question 22

Place on an enzyme where substrate binds

Answer 22

Active Site

Question 23

What determines enzyme-substrate specificity?

Answer 23

3D shape of enzyme and reactants

Question 24

Mild shift in shape of enzyme/substrate that optimizes reactions; expansion of “lock and key” model

Answer 24

Induced Fit

Question 25

What determines the 3D shape of a protein?

Answer 25

Amino Acid Sequence

Question 26

How can an enzyme help the substrate reach its transition state?

Answer 26

1. Position two substrates so they align perfectly
2. Provide an optimal environment within active site
3. Contort/stress substrate so it’s more likely to react
4. Temporarily react with substrate

Question 27

How can enzymes be regulated?

Answer 27

1. Modifications to temp. or pH
2. Production of molecules that inhibit/promote enzyme function
3. Availability of coenzymes or cofactors

Question 28

Have a similar shape to substrate that competes with it for the active site; slow reactions without affecting maximal rate

Answer 28

Competitive Inhibitors

Question 29

Bind to the enzyme at a different location than the active site, causing a slower reaction rate; slow reaction rates and reduce maximal rates

Answer 29

Noncompetitive Inhibitors

Question 30

Modify active site of an enzyme so substrate binding is reduced/prevented

Answer 30

Allosteric Inhibitors

Question 31

Modify active site of an enzyme so affinity for substrate increases

Answer 31

Allosteric Activators

Question 32

Inorganic helper ions (iron or magnesium)

Answer 32

Cofactors

Question 33

Organic helper molecules (vitamin C)

Answer 33

Coenzymes

Question 34

Enzymes required for certain cellular processes are housed separately inside structures with their substrates

Answer 34

Compartmentalization

Question 35

End product of a pathway inhibits an upstream step; important regulatory mechanism in cells

Answer 35

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