Metabolism

Question 1

Energy:

Answer 1

Capacity to do work

Question 2

Chemical Work

Answer 2

making and breaking of chemical bonds

Question 3

Transport Work

Answer 3

moving ions, molecules, and larger particles
can create concentration gradients

Question 4

Mechanical work

Answer 4

used for movement

Question 5

first law of thermodynamics

Answer 5

-law of conservation of energy
-“total amount of energy in the universe is constant”
-closed system

Question 6

second law of thermodynamics

Answer 6

-push to entropy
-“processes move from state of order to disorder”

Question 7

Activation energy

Answer 7

the energy that msut be put into reactants before a reaction can proceed

Question 8

Exergonic reactions

Answer 8

energy is released
products have less energy than the starting substance

Question 9

endergonic reactions

Answer 9

energy input required
product has more energy than starting substances

Question 10

large activation energy makes reactions

Answer 10

irreversible

Question 11

enzymes are

Answer 11

catalytic molecules

Question 12

enzyme function (7)

Answer 12

1. speed the rate at which reactions approach equilibrium
2. nearly all enzymes are proteins
3. highly specific
4. enzymes are very efficient
5. enzymes are subject to a variety of controls
6. larger than substrates (reactants)
7. few kinds of RNAs also show enzymatic activity (e.g. ribozymes)

Question 13

an enzyme speeds up a chemical reaction without

Answer 13

being altered or consumed

Question 14

isozymes

Answer 14

catalyze same reaction, but under different conditions

Question 15

enzymes may be

Answer 15

activated, inactivated, or modulated
-coenzymes, vitamins
-chemical modulators: temperature and pH

Question 16

reversible enzymatic reactions obey

Answer 16

the law of mass action (forward and in reverse)

Question 17

Isozyme example: tyrosine

Answer 17

-the amino acid, tyrosine, is converted to melanin (brown pigment) by the enzyme tyrosinase
-siamese cats and himalayan rabbits have a specific isozyme of tyrosinase that is heat sensitive
-increase temprature, decrease activity of enzyme
-enzyme does not work at core body temperature, but is active in cooler regions of the body (face and tail)

Question 18

law of mass action:

Answer 18

when a reaction is at equilibrium, the ratio of the products and substrates remains constant
(rate of reaction forward= rate of reaction reverse)

Question 19

factors that influence the rate of an enzyme-catalyzed reaction (5)

Answer 19

-temperature
-pH
-substrate concentration
-non-substrate chemicals that bind to the enzyme (competitive inhibitors & allosteric modulators)
-metabolic pathways (feedback inhibition or end-product inhibition)

Question 20

A group of metabolic pathways resembles

Answer 20

a road map

Question 21

Cells Regulate their Metabolic Pathways (5)

Answer 21

1. controlling enzyme concentrations
2. producing allosteric and covalent modulators
3. using different enzymes for reversible reactions
4. isolating enzymes within organelles
5. maintaining optimum ratio of ATP to ADP

Question 22

Energy Utilization or Metabolism consists of 2 pathways:

Answer 22

catabolic and anabolic

Question 23

Catabolic Pathways

Answer 23

-extract energy for ATP production
-dependent on exergonic reactions

Question 24

Anabolic Pathways

Answer 24

-synthesis pathways
-energy converted to chemical bonds
-dependent on endergonic reactions

Question 25

ATP production has 2 methods

Answer 25

1. substrate-level phosphorylation
2. oxidative phosphorylation

Question 26

glycogen

Answer 26

-storage form of glucose in liver and skeletal muscle
-converted to glucose or glucose 6-phosphate

Question 27

gluoneogenesis is

Answer 27

the conversion of noncarbohydrate molecules (lactic acid, amino acids, glycerol) into a glucose molecule

Question 28

lipid catabolism involves

Answer 28

lipolysis and beta oxidation

Question 29

deamination of an amino acid produces ammonia and a

Answer 29

keto acid