UNIT - Metabolism and Survival

Question 1

Anabolic Reaction

Answer 1

Involves simple substances being built up to form larger more complex molecules. This requires ATP/energy.

Question 2

Catabolic Reaction

Answer 2

Involves the breakdown of larger more complex molecules into simpler substances. This releases ATP/energy.

Question 3

Cell Membrane

Answer 3

Boundary between the cell contents and external surroundings of the cell, it regulates the movement of materials into and out of the cell. It is composed of proteins and phospholipids (arranged in a phospholipid bilayer).

Question 4

Activation Energy

Answer 4

The minimum energy required for chemical molecules to react successfully within a cell.

Question 5

Induced Fit

Answer 5

When an enzyme changes shape slightly to fit more closely to the substrate, increasing the rate of reaction.

Question 6

Competitive Inhibitors

Answer 6

These are inhibitors that act by binding to the active site of an enzyme preventing the substrate from binding. This can be reversed by increasing the concentration of the substrate.

Question 7

Non-Competitive Inhibitors

Answer 7

These are inhibitors that work by binding to a site called the allosteric site. This changes the shape of the active site meaning the substrate can no longer bind. This is irreversible.

Question 8

Feedback Inhibition

Answer 8

This occurs when an end product inhibits the activity of an enzyme that catalysed a reaction earlier in the pathway that produced the end product.

Question 9

Glycolysis

Answer 9

The breakdown of glucose to pyruvate in the cytoplasm (both an aerobic and anaerobic process).

Question 10

Co-enzyme A

Answer 10

Combines with acetyl group to form acetyl-co-enzyme A and enters the citric acid cycle.

Question 11

Dehydrogenase Enzymes

Answer 11

Enzymes that remove H ions and electrons.

Question 12

Final Hydrogen Acceptor in Respiration

Answer 12

Oxygen which combines the Hydrogen to form water.

Question 13

Alternative Respiratory Substrates

Answer 13

Other sugars (broken down into glucose or intermediate of glycolysis), Fat (broken down to fatty acids and glycerol), Protein (broken down into amino acids).

Question 14

Single Circulatory System

Answer 14

Found in fish where there is only one atrium and ventricle. Blood passes through the heart once so it loses pressure.

Question 15

Incomplete Double Circulatory System

Answer 15

Found in Reptiles and Amphibians. Blood passes through the heart twice but as there is only one ventricle there is the mixing of oxygenated and deoxygenated blood so the blood delivered to cells is incompletely oxygenated.

Question 16

Complete Double Circulatory System

Answer 16

Found in mammals and birds. The heart has two atria and ventricles with a wall completely separating the oxygenated and deoxygenated blood. This is the most efficient oxygen delivery system.

Question 17

VO2 Max

Answer 17

The measure of the peak volume of O2 you can consume and use in a minute.

Question 18

Conformer

Answer 18

Animal that cannot maintain metabolic rate using physiological mechanisms and rely directly on their external environment to regulate their internal environment. This means they have a low metabolic cost but can only occupy a narrow range of ecological niches.

Question 19

Regulator

Answer 19

Animal that can maintain its metabolic rate using physiological mechanisms (homeostasis). This requires large amounts of energy and they have a large metabolic cost but means they can occupy a large range of ecological niches.

Question 20

Predictive Dormancy

Answer 20

This dormancy occurs before the onset of the adverse conditions. Normally genetic and occurs in places with predictable seasons where it can be triggered by environmental cues such as temperature and photoperiod.

Question 21

Consequential Dormancy

Answer 21

This dormancy occurs after the onset of adverse conditions. A response to an unpredictable environment eg. High altitudes.

Question 22

Hibernation

Answer 22

Form of Dormancy employed by many mammals in response to winter and lack of food. The mammal will reduce its metabolic rate by lowering heart rate, breathing rate and body temperature. This will reduce the energy requirements during the harsh months of winter allowing them to survive.

Question 23

Aestivation

Answer 23

Allows some animals to survive periods of high temperature and drought. Often the animal burrows into the ground where it is cooler and may secrete mucus to cover their body giving them a layer of moisture.

Question 24

Daily Torpor

Answer 24

Small birds and mammals with a high metabolic rate will go into a state of torpor for periods during the day to reduce their metabolic cost.

Question 25

Migration

Answer 25

A behaviour used to avoid adverse conditions. This involves the long term movement of individuals, usually taking place on a seasonal basis.

Question 26

Extremophiles

Answer 26

Organisms that live in extreme conditions where most others would be unable to survive.

Question 27

Lag Phase

Answer 27

Enzyme Induction- the microorganisms adjust to their conditions and produce the enzymes necessary to use the available substrate for their metabolic processes.

Question 28

Log/Exponential Phase

Answer 28

Population doubles with each successive cell division.

Question 29

Stationary Phase

Answer 29

Food source has been used up and oxygen is in short supply. Toxic metabolites may be released. The production of new cells equals the rate of cell death resulting in no increase in population.

Question 30

Death Phase

Answer 30

The lack of usable substrate and the accumulation of high concentrations of toxic metabolites causes the death rate to be higher than birth rate so population decreases.

Question 31

Precursor

Answer 31

Substance which is acted on by an enzyme to ensure that a desired metabolite is produced later in the same pathway.

Question 32

Inducer

Answer 32

Substance which triggers the production of a specific enzyme which then produces the required metabolite.

Question 33

Mutagenesis

Answer 33

Process of inducing mutations in a microorganism.

Question 34

Restriction Site

Answer 34

Location on the plasmid that can be cut open for the insertion of the required human gene.

Question 35

Origin of Replication

Answer 35

The area on the plasmid that contains all the genes necessary for self replication which is essential if the plasmid is to make copies of itself.

Question 36

Marker Genes

Answer 36

A gene which is deliberately transferred along with the required gene on the plasmid. It is easy to recognise and can be used to identify cells to which the gene has been successfully transferred to. There are two types- gene for antibiotic resistance or gene which makes cells containing the recombinant DNA look different.