Introduction to Metabolism

Question 1

Metabolism

Answer 1

a sum of all chemical reactions in a cell or organism

Question 2

Metabolic pathway

Answer 2

a sequence of chemical reactions undergone by a compound in a living organism

Question 3

Catabolism

Answer 3

complex molecules are broken down into simple molecules

Question 4

Anabolism

Answer 4

build complex molecules from simple sugars

Question 5

oxidation

Answer 5

a reaction in which a molecule loses electrons

Question 6

reduction

Answer 6

a reaction in which a molecule gains electrons

Question 7

Kinetic energy

Answer 7

energy in motion
ex. water spilling over a damn can be harnessed to do eo work since its in motion. Heat and light, heart muscles contraction.

Question 8

Potential energy

Answer 8

stored energy by virtue of an objects position within an attractive or repulsive force field
ex. water backed up behind a dam is not doing any work, but could do work if released.

Question 9

Work

Answer 9

is the transfer of energy from one body to another
ex, apple falling, potential energy is converted into kinetic energy when the apple falls. As the speed increases, the apple looses potential energy and gains kinetic energy.

Question 10

thermodynamics

Answer 10

branch of science dealing with the laws and theories related to energy in the universe. Theres 2 laws.

Question 11

first law of thermodynamics

Answer 11

states that the total amount of energy in the universe is constant. Energy cannot be created nor destroyed but only converted from one form to another.

Question 12

Bond energy

Answer 12

the measure of stability of a covalent bond. different molecules have different stabilities.

Question 13

Potential Energy diagrams

Answer 13

shows the changes in potential energy that takes place during chemical reaction

Question 14

Activation energy

Answer 14

the difference between the potential energy level and the transition state and the potential energy of reacting molecules.

Question 15

Transition state

Answer 15

in a chemical reaction a temporary condition in which the bonds within the reactants are breaking and the bonds between products are forming.

Question 16

enthalpy

Answer 16

over all change in energy that takes place in a reaction

Question 17

endothermic reaction

Answer 17

delta H is positive

Question 18

exothermic reaction

Answer 18

delta H is negative

Question 19

Entropy

Answer 19

a physical property and it is a measure of disorder or uncertainty about a system
Entropy increases when disorder increases
ex. solid reactants become liquid or gaseous products
- liquid reactants become gaseous products

Question 20

Gibbs free energy

Answer 20

energy that can do useful work, also called Gibbs free energy
delta G neg. is spontaneous, pos. is not spontaneous

Question 21

Second Law of thermodynamics

Answer 21

any time you do work, including any time you make energy transformation, some of the starting energy is going to be lost as heat
Major complications:
- no process is 100% efficient

Question 22

Coupling free energy - yielding

Answer 22

which is (exergonic) catabolic process with energy-requiring (endergonic) anabolic process, living things build up their bodies around them.

Question 23

Exergonic reactions

Answer 23

chemical reaction in which the energy of the products is less then the energy of reactants
ex. cellular respiration

Question 24

Endergonic reactions

Answer 24

chemical reaction which the energy of the products is more than the energy of reactants
ex. Photosynthesis

Question 25

Why Metabolic pathways are reversible?

Answer 25

Metabolic reactions are enzymes catalyzed and are reversible, when a reversible reaction reaches an equilibrium its delta G = zero and its free energy content is zero.
A cell whose reversible reactions reach equilibrium is a dead cell