4.1 Biochemical pathways for chemical metabolism

Question 1

What are enzymes?

Answer 1

Catalysts in biochemical pathways

Question 2

Are enzymes soluble in water?

Answer 2

Yes, most of the time

Question 3

What is a substrate?

Answer 3

A molecule that an enzyme acts upon

Question 4

What is an enzyme-substrate complex?

Answer 4

A structure where a substrate has bound with an enzyme

Question 5

What is the structure of an enzyme?

Answer 5

A bundle of amino acids, forming the shape

Question 6

What is enzyme specificity?

Answer 6

This determines how specific an enzyme is to its substrate.

Question 7

What are the two models that can present enzyme specificity?

Answer 7

Lock and Key model and Induced-fit model

Question 8

Explain the lock and key model

Answer 8

Only one size fits the shape; enzyme like a lock, substrate like a key; active site is assumed rigid

Question 9

Explain the induced-fit model

Answer 9

Active site is assumed to be flexible and can fit around substrate tightly; active site is not complementary to substrate

Question 10

What is a biochemical pathway?

Answer 10

The regulation of metabolic reactions; occurs in pathways that involve series of regulated steps controlled by enzymes; it is a negative feedback loop

Question 11

Define catalytic power

Answer 11

The ability of an enzyme to increase the rate of a biochemical reaction, compared to the reaction occurring without the enzyme present

Question 12

What is catabolism?

Answer 12

An exergonic reaction that releases energy and heat (exothermic); involves breaking down of a substrate and is involved in cellular respiration

Question 13

What is anabolism?

Answer 13

An endergonic reaction that requires energy, making it endothermic; involves synthesis of new molecules and is involved in photosynthesis

Question 14

What is activation energy?

Answer 14

An input of energy to start a reaction; enzymes allow for activation energy to reduce, so less energy is required from the body

Question 15

What structure forms when a substrate binds to the active site of an enzyme?

Answer 15

An enzyme substrate complex

Question 16

What model of enzyme so if it’s looks like a lock fitting in a key

Answer 16

Lock and key model

Question 17

What model of enzyme specificity is similar to a glove changing shape as a hand slips into it?

Answer 17

The induced-fit model

Question 18

What type of loop is a metabolic reaction?

Answer 18

A negative feedback loop

Question 19

Is catabolism exergonic or endergonic?

Answer 19

Exergonic

Question 20

Is anabolism exergonic or endergonic?

Answer 20

Endergonic

Question 21

Is energy required or released in catabolism?

Answer 21

Energy is released

Question 22

Is energy required or released in anabolism?

Answer 22

Energy is required

Question 23

Is catabolism the break down or synthesis of substrate?

Answer 23

The breakdown of substrate

Question 24

Is anabolism the breakdown or synthesis of substrate?

Answer 24

Synthesis of substrate

Question 25

Is photosynthesis an example of catabolism or anabolism?

Answer 25

Anabolism

Question 26

Is cellular respiration an example of catabolism or anabolism?

Answer 26

Catabolism

Question 27

Is catabolism exothermic or endothermic?

Answer 27

Exothermic

Question 28

Is anabolism exothermic or endothermic?

Answer 28

Endothermic

Question 29

Define cellular metabolism

Answer 29

The sum of metabolic reactions in a cell

Question 30

Define anabolic reaction

Answer 30

A reaction in which atoms and small molecules are joined together to make larger molecules; requires an initial input of energy so they can start to form new chemical bonds

Question 31

Define endergonic reaction

Answer 31

A reaction that requires an initial input of energy to get them started

Question 32

Define endothermic reaction

Answer 32

A reaction where light energy is absorbed from the surroundings and used to form bonds in a formed molecule

Question 33

Define catabolic reaction

Answer 33

Complex molecules are broken down into simpler molecules; spontaneous reactions that do not require and initial input of energy.

Question 34

Define exergonic reaction

Answer 34

A reaction that does not require an initial input if energy

Question 35

Define exothermic

Answer 35

A reaction that releases energy

Question 36

Define reactants

Answer 36

The inputs of a chemical reaction

Question 37

What are cofactors/ coenzymes?

Answer 37

Molecules that assist enzymes

Question 38

Define catalyst

Answer 38

A substance that increases the rate of a reaction without itself undergoing any permanent chemical change

Question 39

What is photosynthesis?

Answer 39

The process by which photoautotrophs capture light energy and use it to convert water and carbon dioxide to glucose and oxygen

Question 40

Where does photosynthesis occur?

Answer 40

In chlorophyll molecules of plants

Question 41

What is glycogen?

Answer 41

The stored form of glucose in animals

Question 42

How is glucose stored for long term?

Answer 42

Glycogen in animals, starch in plants

Question 43

What is cellular respiration?

Answer 43

The process of breaking down glucose either completely in aerobic respiration using oxygen, or incompletely in anaerobic respiration when no oxygen is used

Question 44

What is the purpose of cellular respiration?

Answer 44

To release the energy stored in the bonds of glucose to form the energy storage molecule adenosine triphosphate (ATP)

Question 45

What is adenosine triphosphate (ATP)

Answer 45

The ‘energy bank’ of cells,which can make energy available to cells when it’s needed

Question 46

What is the structure of ATP?

Answer 46

Contains an adenosine molecule, attached to a sugar group (ribose), which is bound to a chain of 3 phosphate groups

Question 47

How is ATP formed?

Answer 47

By the addition of a phosphate group to an adenosine diphosphate (ADP) molecule in a reversible reaction catalysed by an enzyme ATP synthase

Question 48

What is ADP?

Answer 48

A low-energy compound that when a phosphate group is added to it, it is converted into ATP for energy storage

Question 49

What is ATP synthase

Answer 49

An enzyme that provides energy for the cell through the synthesis of ATP

Question 50

Where does cellular respiration occur?

Answer 50

In the chronological and mitochondria

Question 51

What is the outputs of anaerobic cellular respiration in plants?

Answer 51

Ethanol, carbon dioxide and 2ATP

Question 52

What are the outputs of anaerobic cellular respiration in animals?

Answer 52

Lactic acid and 2ATP