3.1 Metabolism & Energy

Question 1

Metabolism

Answer 1

The sum of all chemical rxns in a cell or organism

Question 2

Kinetic energy

Answer 2

The energy of motion

Question 3

Potential energy

Answer 3

The stored energy that an object possesses as a result of its position relative to other subjects or to its internal structure

Question 4

1st Law of Thermodynamics

Answer 4

Principle that states that energy can be transferred or transformed, but it can’t be created or destroyed

Question 5

Bond energy

Answer 5

The minimum amount of energy that’s required to break a particular type of bond: measured in KJ/mol of bonds

Question 6

Exothermic rxn

Answer 6

A chem. rxn in which energy is released, leaving the products with less chemical potential energy that the reactants

Question 6

Activation energy, Ea

Answer 6

The minimum amount of energy that chemical reactants must absorb to start a rxn

Question 6

Transition state

Answer 6

A temporary condition during a chemical rxn in which the bonds in the reactants are breaking and the bonds in the products are forming

Question 7

Mole

Answer 7

6.02x10^23 atoms or molecules

Question 8

Endothermic rxn

Answer 8

A chem. rxn in which energy is absorbed, giving the products more chemical potential energy that the reactants.

Question 9

2nd Law of Thermodynamics

Answer 9

Principle that states that every time energy is converted to another form, some of the energy becomes unusable

Question 10

Entropy

Answer 10

A measurement of disorder in a system

Question 11

Spontaneous change

Answer 11

A change that will, once begun, continue on its own under a given set of conditions: does not require a continuous supply of energy.

Question 11

Free energy

Answer 11

Energy that can do useful work: also called Gibbs free energy

Question 12

Exergonic rxn

Answer 12

A chemical rxn that releases free energy; the products have less free energy that the reactants

Question 13

Endergonic rxn

Answer 13

A chemical rxn that absorbs free energy: the products have more free energy that the reactants

Question 14

Anabolic pathway

Answer 14

A pathway in which energy is supplied to build complex molecules from simple molecules

Question 15

Energy coupling

Answer 15

The transfer of energy from 1 rxn to another in order to drive the second rxn

Question 15

Catabolic pathway

Answer 15

A pathway in which energy is released and complex molecules are broken down into simple molecules

Question 16

Anabolic pathway

Answer 16

A pathway in which energy is supplied to build complex molecules from simple molecules

Question 17

Energy

Answer 17

Ability to do work

Question 18

Living organisms must

Answer 18

Capture, store, and use energy

Question 19

Metabolism:

Answer 19

The sum of the chemical rxns taking place, sums up anabolic and catabolic rxns

Question 20

Potential energy EX.

Answer 20

• Gravitational
• Chemical

Question 21

1st Law of Thermodynamics

Answer 21

“Law of energy conservation”
- Energy can’t be created or destroyed; it can only be changed from one form to another

Question 22

Examples of first law of thermodynamics

Answer 22

For example:

1) Light energy comes from the sun

2) Converted to chemical energy by green plants

3) Stored in plant cells as carbs

4) Passed on to other organisms when they eat the plants

5) Converted to other forms: mechanical, thermal, sound…

Question 23

Energy conversion depends on

Answer 23

breaking and reforming chemical bonds

Question 24

Electrons have more P.E the farther

Answer 24

they are from the nucleus

Question 25

Electrons can be attracted

Answer 25

the multiple nuclei at the same time = chemical bond

Question 26

Bonds to break energy is

Answer 26

ABSORBED, so it can be used to pull away an electron

Question 27

New bonds form energy is

Answer 27

RELEASED

Question 28

Every rxn requires energy to

Answer 28

BEGIN the rxn, even it ultimately produces energy ; called activation energy; Ea

Question 29

Intermediate state; when bonds are broken and new ones are ready to be formed, known as the

Answer 29

TRANSITION STATE

Question 30

Exothermic rxn:

Answer 30

Net release of energy

Question 31

Endothermic rxn:

Answer 31

Net absorption of energy

Question 32

2nd law of thermodynamics

Answer 32

Every time energy is converted to
another form, some of the useful energy
becomes unusable and increases the
entropy of the universe

Question 33

Entropy refers to

Answer 33

the degree of disorder in a
system

Question 34

All systems in the universe tend towards

Answer 34

entropy

Question 35

Entropy also increases when # product
molecules

Answer 35

> # reactant molecules

Question 36

Living cells can create order by expending
energy

Answer 36

Entropy of their surroundings increases

Question 37

Spontaneous Changes

One that will continue to occur

Answer 37

on its own once it
has started

E.g. a match will continue to burn once it’s started; a
diver will continue to fall once they have jumped

Question 38

Gibbs Free Energy

Since rxns aren’t 100% efficient,

Answer 38

whatever energy
remains to do work is known as free energy

Question 38

Non-spontaneous requires

Answer 38

continual energy input

E.g. keeping a pot of water boiling

Question 39

Need to look at

Answer 39

energy changes, entropy, and
temperature

Question 40

ΔG = Gfinal – Ginitial

Answer 40

If ΔG is negative, energy is released (exergonic) 🡪
spontaneous

If ΔG is positive, energy is absorbed

Question 41

Coupled Reactions

Cells continuously carry out thousands of rxns

Answer 41

Exergonic rxns release free energy, which can be
used to make endergonic rxns happen

Combined, the rxns have – ΔG, so they occur spontaneously

Question 42

Rxns tend to be part of a

Answer 42

a metabolic pathway

Question 43

Catabolic:

Answer 43

Complex molecules broken down,
releasing energy (e.g. cellular respiration) ΔG -ve

Question 44

Anabolic:

Answer 44

simple molecules combined, consuming
energy (e.g. photosynthesis) ΔG +ve

Question 45

All living things perform activities that

Answer 45

increase the free energy available

• Movement, growth, repair, reproduction

(Continual energy supply is required)

Question 46

This energy comes from

Answer 46

ATP