Unit 2

Question 1

Vo2 max

Answer 1

The maximum rate at which the body is able to take up and use oxygen

Question 2

Calorimeter

Answer 2

A piece of equipment used to measure heat generation from an organism to allow metabolic rate to be calculated.

Question 3

Citric acid/Krebs cycle

Answer 3

The second stage of respiration, where acetyl CoA and oxaloacetate join to form citric acid and a series of reactions which return citric acid to oxaloacetate

Question 4

Dehydrogenase

Answer 4

An enzyme which removes hydrogen ions and electrons from substrates

Question 5

NAD/FAD

Answer 5

A co-enzyme which easily attaches to hydrogen ions, but releases them when they are required

Question 6

Mitochondria

Answer 6

A structure in the cell responsible for producing energy

Question 7

ATP synthase

Answer 7

An enzyme which produces ATP

Question 8

Fermentation

Answer 8

A type of respiration which takes place in the absence of oxygen

Question 9

Respirometer

Answer 9

A piece of equipment used to measure the rate of respiration

Question 10

Glycolysis

Answer 10

The first stage of respiration where glucose is broken down into pyruvate

Question 11

Anabolic

Answer 11

A reaction which requires energy and builds micromolecules up into macromolecules

Question 12

Catabolic

Answer 12

A reaction which releases energy and breaks down macromolecules into micromolecules

Question 13

Selectively permeable

Answer 13

A property of a membrane which means that substances do not freely pass through it. The membrane allows the passage of certain small molecules, but excludes many other molecules.

Question 14

Channel/pore proteins

Answer 14

These proteins allow specific molecules and ions to pass through the membrane, for example, a protein channel found in the plasma membrane allows chloride ions to pass through the membrane.

Question 15

Carrier/pump proteins

Answer 15

As the name suggests, carrier proteins bind to specific molecules or ions temporarily, enabling them to cross the membrane. This involves a change to the conformation of the carrier protein, which may require energy provided by ATP. The sodium-potassium pump is an example of a carrier protein.

Question 16

Enzymes

Answer 16

Some proteins in the membrane catalyse a specific reaction. Some receptor proteins have enzymatic activity, in which the cytoplasmic portion of the protein catalyses a reaction in response to binding by a ligand.

Question 17

Structural support

Answer 17

Some membrane proteins are linked to the cytoskeleton and help to maintain the shape of the cell.

Question 18

Biological catalysts

Answer 18

Catalysts made of protein that are only found in living cells

Question 19

Active site

Answer 19

The region of an enzyme molecule where the enzyme acts on the substrate

Question 20

Induced fit model

Answer 20

A model of an enzyme-substrate reaction that causes a conformational change in the active site of the enzyme that allows the substrate to fit perfectly

Question 21

Competitive inhibition

Answer 21

Competitive inhibition of enzyme activity occurs when an inhibitor, resembling the structure of the substrate, binds to the active site of the enzyme and blocks the binding of the substrate

Question 22

Non-competitive inhibition

Answer 22

A molecule binds to a part of the enzyme away from the active site, and causes a conformational change in the active site of the enzyme, thereby inhibiting the binding of the appropriate substrate molecule

Question 23

Feedback inhibition

Answer 23

Regulation of the enzyme activity where the first enzyme of a metabolic pathway is inhibited but the reversible binding of the appropriate substrate molecule

Question 24

Metabolite

Answer 24

The intermediates and products of metabolic reactions that take place in organisms

Question 25

Activation energy

Answer 25

The minimum energy required by reactants to allow a reaction to occur

Question 26

Receptor

Answer 26

Cells which monitor changes in environment

Question 27

Effector

Answer 27

Cells, muscles or glands which perform responses to stimuli

Question 28

Hypothalamus

Answer 28

Part of the brain which monitors and regulates temperatures

Question 29

Vasodilation

Answer 29

Enlargement in diameter of a blood vessel, thus increasing blood flow. The blood vessels (arterioles) that supply blood to the skin dilate/widen, increasing the amount of blood flowing to the skin. This increases the surface area from which heat can be lost to the environment by radiation.

Question 30

Vasoconstriction

Answer 30

Contration in diameter of a blood vessel, thus increasing in blood flow. The arterioles that supply blood to the skin constrict/narrow, reducing the amount of blood flowing to the skin. As a result less heat is lost by radiation from the surface of their body.

Question 31

Negative feedback

Answer 31

Homeostasis; the process by which an increase in one factor cause a decrease in another factor, thereby maintaining equilibrium around a set point/norm.

Question 32

Daily torpor

Answer 32

A period of reduced activity in organisms with high metabolic rates

Question 33

Hibernation

Answer 33

An inactive state resembling deep sleep in which certain animals living in cold climates pass the winter

Question 34

Aestivation

Answer 34

Dormancy in response to high temperature or drought

Question 35

Migrate

Answer 35

A process which avoids metabolic adversity by expending energy to relocate to a more suitable environment.

Question 36

Psychrophiles

Answer 36

Microbes which live in cold environments such as sea ice, and the Arctic and Antarctic peaks

Question 37

Thermophiles

Answer 37

Microbes that live in very hot environments such as deep sea vents and volcanic lakes

Question 38

Dormancy

Answer 38

A condition of biological rest or inactivity characterised by cessation of growth or development and the suspension of many metabolic processes

Question 39

Alkaphiles

Answer 39

Microbes that live in basic environments like soda lakes

Question 40

Halophiles

Answer 40

Microbes that live in very salty environments such as salt lakes and salt mines

Question 41

Acidophiles

Answer 41

Microbes that live in acidic environments such as sulphur springs.

Question 42

Extremophiles

Answer 42

An organism which is able to live in extreme conditions.

Question 43

Restriction endonuclease

Answer 43

An enzyme that cuts specific target sequences of DNA

Question 44

Ligase

Answer 44

An enzyme which joins fragments of DNA together

Question 45

Wild type

Answer 45

Describes the phenotype of the typical form of a species as it occurs in nature

Question 46

Heterotrophic

Answer 46

An organism which gains energy by consuming other organisms

Question 47

Complex media

Answer 47

Contain one or more crude sources of nutrients and their exact chemical composition and components are unknown

Question 48

Defined media/synthetic media

Answer 48

Media in which the components of the medium are chemically known and are present in relatively pure form

Question 49

Nutrient medium

Answer 49

A mixture of nutrients, includes carbon/nitrogen, required for growth

Question 50

Lag phase

Answer 50

Microorganisms adjust to the conditions of the culture by producing enzymes that metabolise the available substrates

Question 51

Exponential/logarithmic phase

Answer 51

The rate of growth is at its highest

Question 52

Stationary phase

Answer 52

The culture medium becomes depleted and secondary metabolites are produced

Question 53

Death phase

Answer 53

Lack of substrate and the toxic accumulation of metabolites causes death of cells

Question 54

Archaea

Answer 54

A group of single-celled microorganisms