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Biology > Unit two - Metabolism and survival > Flashcards

Unit two - Metabolism and survival Flashcards

1
Q

Describe the difference between a reversible and an irreversible step

A

With a reversible step the product can react to form the original substrate. in am irreversible step the reactants form the product which cannot be reversed.

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2
Q

explain what is meant by an alternative route in a metabolic pathway

A

when a substrate is acted upon by a different enzyme and follows a different pathway to the end product

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3
Q

name an enzyme which is embedded in the inner mitochondrial membrane

A

ATP synthase

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4
Q

describe the role of protein pumps embedded in the inner mitochondrial membrane

A

the use of energy to pump hydrogen ions across the inner mitochondrial membrane

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5
Q

Describe the role of genes in the control of metabolic pathways

A

each step in a metabolic pathway is controlled by a specific enzyme, each enzyme is coded for by a gene, the order of bases in the gene determine the order of the amino acids, which determines the structure of the protein.

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6
Q

describe the role of the active site of an enzyme during a reaction

A

The active site has a slightly high affinity for the substrate molecule and a low affinity for the products. this lowers the activation energy of the chemical reaction

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7
Q

Describe the mechanism of induced fit

A

the enzyme is flexible and so the active site can change shape, the substrate induces the active site to change shape, and the active site can orientate the position of the substrate molecules so they fit better.

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8
Q

describe the effect of an increase in substrate concentration on the direction and rate of an enzyme reaction

A

increase in substrate concentration drives the chemical reaction in the direction of the end product and increases the rate of reaction

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9
Q

Explain how enzymes speed up the rate of reaction in metabolic pathways

A

The active site can alter the position of the substrate molecules so that they fit more closely, and the activation energy is lowered when an enzyme is involved

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10
Q

describe the effect of substrate concentration and end- product concentration on a reversible metabolic reaction

A

increase substrate concentration drives the chemical reaction in the direction of the end product, increase in the end product concentration drive the chemical reaction in the direction of the substrate.

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11
Q

describe the effect of increasing concentration on the rate of reaction in the presence of a competitive inhibitor

A

reaction rate increases with the substrate concentration, but as substrate concentration increases further there is no further effect on the rate of reaction

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12
Q

describe the effect of increasing substrate concentration on the rate of reaction in the presence of non-competitive inhibitors

A

inhibitors reduce the rates of reaction nearly to 0 increasing substrate concentration makes no difference.

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13
Q

explain the advantages of end-product inhibition to a cell

A

stops the production of too much end product

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14
Q

explain the difference between a competitive and a non-competitive inhibitor

A

competitive inhibitors binds reversibly at the active site, and non-competitive inhibitors binds irreversibly at another binding site.

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15
Q

explain the effect of a competitive inhibitor on the rate of reaction

A

the rate of the enzyme reaction decreases, and competitive inhibitors have a similar shape to the substrate molecule and attaches at the active site of the enzyme

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16
Q

explain the effect of a non-competitive inhibitor on the rate of reaction

A

the rate of reaction is reduced to nearly zero and inhibitors cause a change in the shape of the active site so that the substrate cannot bind

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17
Q

Explain why the phosphorylation of intermediates in glycolysis is referred tp as an energy investment stage

A

Two ATP molecules are used to phosphorylate the intermediates in the energy investment stage, and four ATP molecules are gained in the pay-off stage

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18
Q

Describe the role of the dehydrogenase enzymes in glycolysis and the citric acid cycle

A

Dehydrogenase enzymes remove hydrogen ions and electrons

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19
Q

Explain the role of ATP during glycolysis

A

In glycolysis, ATP is used in the phosphorylation of glucose and intermediates

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20
Q

Explain why the ATP produced in glycolysis is referred to as an energy pay-off

A

Four ATP molecules are produced in the pay-off stage, this gives a net gain of 2 ATP

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21
Q

Describe the role of the co-enzyme NAD

A

It transports hydrogen ions and electrons to the electron transport chain

22
Q

Describe how hydrogen ions caused the synthesis of ATP during respiration

A

ATP is regenerated as the hydrogen ions flow back through the ATP synthase

23
Q

describe how the role of the electrons that pass down the electron transport chain

A

it releases energy to pump the hydrogen ions across the inner membrane of the mitochondria

24
Q

describe the role of proteins in the electron transport chain

A

the electrons cascade down the chain of proteins releasing energy and to pump the hydrogen ions across the inner membrane of the mitochondria

25
Q

describe the role played by oxygen in the electron transport chain

A

Acts as the final electron acceptor combines with hydrogen ions and electrons to form water

26
Q

Compare the products of fermentation in animal and yeast cells

A

Fermentation in animal cells produces lactate but in yeast cells produces ethanol and CO2, fermentation in animals is reversible but in yeast cells it is irreversible

27
Q

describe the role of ATP in cell metabolism

A

ATP is used to transfer the energy from cellular respiration to cellular process which requires energy

28
Q

name to cellular processes which are anabolic

A

protein synthesis

transcription

translation

DNA replication

29
Q

Describe to measurements which can be used in determining the metabolic rate os an organism

A

oxygen consumed in a given period of time and carbon dioxide produced in a given period of time and the energy released as heat in a given period of time

30
Q

Explain why the structure of a mammalian heart makes it more efficient than the heart of a fish

A

Mammals have four chambered heart this helps deliver oxygen at higher blood pressure to tissues

31
Q

Explain why organisms with a high metabolic rate require an efficient delivery of oxygen to their cells

A

More oxygen so more aerobic respiration and more ATP needed to maintain high metabolic rate.

32
Q

Explain how the heart of a mammal is better adapted than the heart of an amphibian to allow high metabolic rates in the cells that it supplies with blood

A

in mammals, fully oxygenated blood can be delivered to the muscles because heart has two ventricles, and amphibians incompletely oxygenated blood is delivered to the muscles because the heart has only one ventricle where blood can mix

33
Q

Explain why the circulatory system of mammals needs to be more efficient than those of the other vertebrates shown

A

Mammals have higher metabolic rates and they require more efficient delivery of oxygen to cells

34
Q

Explain how a named abiotic factor can affect the ability of an organism to maintain it metabolic rate

A

Temperature affects the enzyme activity

35
Q

Explain why conformers have low metabolic costs

A

They do not use physiological mechanisms to control their metabolic rate, however this requires energy

36
Q

Explain why conformers usually have a narrow ecological niche

A

conformers lack the ability to tolerate environmental change should it occur

37
Q

Explain why regulators can occupy a wide range of ecological niches

A

Because they can maintain their internal environment in a wide range of conditions using their metabolism

38
Q

Explain why regulators have high metabolic costs

A

the use energy to maintain homeostasis

39
Q

Describe the response of a mammal to an increase in body temperature

A

increased sweat productions

vasodilation of blood vessels

hair erector muscles relaxed

40
Q

Explain the advantage of a mammal vasoconstriction of its blood vessels when skin temperature drops from 20 to 5 degrees

A

Reduces the volume of blood flow to skin surface this reduces heat loss by radiation

41
Q

Describe the role of negative feedback control in thermoregulation

A

Ensures that when the body temperature returns to normal the corrective mechanisms are switched off.

42
Q

Explain why regulating body temperature is important to the metabolism of mammals

A

Mammals maintain the optimum temperature for enzyme activity so can maintain a high metabolic rate, rates of diffusion of substances such as oxygen and carbon dioxide are faster, which helps to maintain a high metabolic rate.

43
Q

Explain the importance of thermoregulation to mammals

A

Mammals can maintain the optimum temperature for enzyme activity so can maintain a high metabolic rate, rates of diffusion of substances such as oxygen and carbon dioxide which helps maintain a high metabolic rate.

44
Q

Describe the difference between consequential and predictive dormancy

A

Predicitive dormancy is when an organism becomes dormant before onset of the adverse conditions, Consequential dormancy is when an organism becomes dormant after the onset of adverse conditions.

45
Q

Explain the benefit to some animals of being able to undergo daily torpor

A

It increases an organisms chances of survival by reducing the energy required to maintain a high metabolic rate

46
Q

Explain the survival role fo aestivation

A

Aestivation allows survival in periods of high temperature when there would be a lack of food and water.

47
Q

Explain the survival role of hibernation in some mammals

A

Hibernation allows survival in periods of low temperature when organisms would not able to meet its metabolic costs

48
Q

Explain the benefit to some animals of being able to migrate

A

Adverse conditions are avoided by migrating

49
Q

Describe a technique which could be used to track species which undertake long-distance migration

A

Transmitters and receivers

50
Q

In culturing bacteria it is important to control the pH of the culture medium. Explain why the pH of a culture medium should be controlled.

A

pH is a factor which affects rates of enzyme activity, in fermenters buffers can be added to maintain optimum pH conditions for enzyme activity.

Biology (4 decks)

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