Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A Level Biology > Energy and Respiration > Flashcards

Energy and Respiration Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

2 ways to give a continuous supply of energy

A
  1. Absorption of light energy

2. From chemical potential energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is supplied to an ecosystem by photosynthesis?

A
  1. Energy supply

2. Usable carbon compounds (To make biological molecules)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name the2 types of organisms based on how they get their energy.

A
  1. Autotrophs: Traps an inorganic carbon source using the energy from light/ chemicals.
  2. Heterotrophs: Needs a supply of organic molecules as a carbon source.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does work in a living organism include?

A
  1. Anabolic reactions
    - simple compounds -> Complex compounds
  2. Active Transport:
    e.g. Na+/K+ pumps
  3. Mechanical work:
    muscle contraction; cellular movements; amoeboid movements; Vesicle movements
  4. Bioluminescence and Electrical discharge.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the difference between ectotherms and endotherms?

A

Ectotherms: Thermal energy is from outside
Endotherms: releases thermal energy from within the body to maintain a constant temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why are energy-yielding reactions multi-stepped?

A
  1. So that energy can be fully harnessed.

2. High Activation energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is high activation energy overcome?

A
  1. Lowering using enzymes

2. Phosphorylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why is ATP used rather than directly using thermal energy?

A

It an intermediary molecule that makes energy-yielding more flexible.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the energy releases associated with ATP and its phosphates

A
  1. ATP -> ADP: 30.5 KJ
  2. ADP -> AMP: 30.5 KJ
  3. AMP -> A: 14.2 KJ
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What causes the energy changes in ATP hydrolysis?

A

The changes in chemical potential energy of all parts of the system,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the reversible reaction for the interconversion of ATP to ADP?

A

ATP + H2O ADP + H3PO4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why is ATP suitable for the energy currency in living organisms? [5]

A
  1. Small and water-soluble so it can move around the cell
  2. It can be readily hydrolysed to produce energy
  3. It is an immediate donor of energy
  4. It can link between energy-yielding and energy-requiring reactions
  5. It has a high turnover of energy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What causes the release of thermal energy with respect to the activity of ATP?

A
  1. Energy yielding: Energy made available does not perfectly correspond to the energy required to synthesise ATP.
  2. ATP release of energy: Energy requiring reactions do not use as much energy as released by ATP.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the difference between an energy currency molecule and an energy storage molecule?

A

Energy currency: Immediate donor of energy to the cell’s energy-requiring reactions.
Energy storage: A short term or long terms storage of chemical potential energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 2 processes that produce ATP?

A
  1. Oxidative Phosphorylation: From the transfer of electrons by electron carriers in mitochondria
  2. Substrate level Phosphorylation: Glycolysis and the Krebbs Cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is ATP Synthase?

A

An enzyme that catalyses the phosphorylation of ADP to ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How many protons for 1 ATP?

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is chemiosmosis?

A

The synthesis of ATP using energy stored as a difference in hydrogen ion concentration across a membrane in a chloroplast/ mitochondria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the sequence of ATP synthesis?

A
  1. Binding of ADP and P
  2. forming tightly bound ATP
  3. releasing ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the sodium-potassium pump?

A

It is a protein that spans the cell surface membrane. It has binding sites for Na+ and ATP on the outer side and K+ on the inside.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the function of and the Na+/K+ pumped?

A

Acts as an ATPase and catalyses the hydrolysis of ATP to ADP and inorganic phosphate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the relationship between the movement of sodium and potassium in the Na+/K+ pump?

A

For each ATP, there is a movement of 2 K+ and 3 Na+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe the exaggeration of the ion gradient across the Na+/K+ pump.

A

there is leakage of the Na+ and K+ through the bilayer.

K+ is more permeable than Na+ that increases the negative potential inside the cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is substrate level phosphorylation?

A

The process by which ATP is synthesised directly, without involving the electron transport chain and a proton gradient; substrate level phosphorylation occurs in glycolysis and the Krebs cycle.
- It involves the transfer of phosphate group to ADP to make an ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the Krebs cycle?

A

A sequence of reactions that occurs in the mitochondrial matrix resulting in the formation of carbon dioxide reduced hydrogen carriers and ATP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a coenzyme?

A

They help enzyme to catalyse reactions.

e.g. NAD takes away the H+ after the enzyme removes it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the co enzymes responsible for respiration?

A
  1. Coenzyme A
  2. Nicotinamide adenine dinucleotide (NAD)
  3. Flavin adenine dinucleotide (FAD)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the role of coenzyme A?

A

It transfer the acetyl groups produced in the link reaction from pyruvate to the krebs cycle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are NAD and FAD?

A

They are known as hydrogen carriers (or electron carriers), since they can combine with hydrogen, formed in some of the reactions of respiration.
NAD + 2H -> reduced NAD
FAD + 2H -> reduced FAD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is oxidative phosphorylation?

A

The production of ATP associated with the oxidation of reduced hydrogen carriers via the electron transport chain in the mitochondria.

31
Q

Describe the process of Chemiosmosis and oxidative phosphorylation.

A
  1. Hydrogen is removed from its carriers and is split into its constituent proton and electron.
  2. The electron is then passed into the electron transport chain: electrons pass from one carrier to another, while pumping protons into the inter-membrane space.
  3. Protons accumulate in the matrix, setting up a high conc gradient.
  4. They flow in through the channel protein ATP synthase.
  5. As they pass through their electrical potential energy is used to synthesise ATP from ADP
  6. Finally, the protons and the electrons combine to form water.
32
Q

Why do lipids produce more ATP than carbohydrates?

A
  • More C-H bonds
  • Produced more reduced NAD
  • Produced more ATP per unit mass
  • More aerobic respiration/ chemiosmosis
  • Fats are only broken down aerobically
33
Q

What is the electron transport chain?

A

Present in the inner mitochondrial membrane, a system of carriers that transport electrons to oxygen, the final acceptor in aerobic respiration.

34
Q

What is the respiratory Quotient?

A

It is the ratio of the volume of carbon dioxide produced to the volume of oxygen used, in a given time, in respiration.

35
Q

What are the 4 main stages of aerobic respiration?

A
  1. Glycolysis
  2. Link reaction
  3. Krebs Cycle
  4. Oxidative phosphorylation
36
Q

In what locations do the different stages of aerobic respiration occur?

A
  1. Glycolysis: Cytoplasm/ cytosol
  2. Link reaction: Mitochondrial matrix
  3. Krebs cycle: Mitochondrial matrix
  4. Oxidative phosphorylation: inner mitochondrial membranes
37
Q

What is Glycolysis?
What is the high level reaction?
When does it happen?
Where does it happen?

A
  • It is the lysis of glucose
  • Glucose (6C) -> 2x Pyruvate + 2x ATP
  • During both, Aerobic and Anaerobic respiration
  • In the cytoplasm
38
Q

What are the 3 main stages of glycolysis?

A
  1. Phosphorylating glucose to glucose phosphate
  2. The production of triose phosphate
  3. Oxidation of triose phosphate to produce pyruvate
39
Q

What is phosphorylation?
Why does glucose have to be phosphorylated?
What is needed for the phosphorylation of glucose?
What is the sequence of phosphorylated carbohydrates that follow glucose phosphorylation?

A
  • The addition of phosphate groups to an organic molecule
  • Glucose is very stable so the reaction needs to be made easier
  • 2 ADP molecules
  • Glucose 6-phosphate -> Fructose 6-phosphate -> Fructose 1,6-biphosphate -> 2x Triose phosphate (glyceraldehyde 3-phosphate) §
40
Q

Describe the oxidation of triose phosphate to produce pyruvate.
What happens to the pyruvate after glycolysis?

A
  • The hydrogen is removed from triose phosphate by NAD
  • 2 molecules of reduced NAD is produced for each pyruvate
  • 2 molecules of ATP is also produced
  • it proceeds to the link reaction
41
Q

What is the link reaction?
What are the 2 subprocesses involved in it?
What is its overall chemical equation?
What is another way that acetyl Coenzyme can be produced?

A

-Occurs in the mitochondrial matrix and links the glycolysis to the Krebs cycle; pyruvate is converted to acetyl CoA, with the formation of carbon dioxide and reduced NAD.
-Decarboxylation and Dehydrogenation
pyruvate + CoA + NAD -> acetyl CoA + CO2 + reduced NAD
-Fat metabolism: long fat chains are shortened to the acetyl unit.

42
Q

What is Coenzyme A and what is its function?

A

It is a complex molecule composed of a nucleoside (adenine + ribose) with a vitamin (pantothenic acid) and it acts a carrier of acetyl groups to the Krebs cycle.

43
Q

What is the Krebs cycle?

A

It is a sequence of reactions that occurs in the mitochondrial matrix, resulting in the formation of carbon dioxide , reduced hydrogen carriers and ATP.

44
Q

What is the purpose of the Krebs cycle?

What are the main stages and reactions of the Krebs Cycle?

A
  • The four carbon compound oxoacetate reacts with the acetyl group to form a 6 carbon citrate. Citrate is then converted back to oxaloacetate.
  • Reactions:
    1. Decarboxylation - removal of CO2
    2. Dehydrogenation of intermediate substances - producing reduced NAD and FAD
    3. Substrate level phosphorylation - production of ATP
45
Q

What is produce in each turn of the Krebs cycle?

A
  • 2 molecules of CO2
  • 1 molecule. of reduced FAD
  • 3 molecules of reduced NAD
  • 1 molecule of ATP
46
Q

How can the rate of factors such as temperature on respiration be investigated?

A
  • Using redox indicators (artificial hydrogen acceptors)

- Redox indicators such as DCPIP and methylene blue change colour when they are reduced.

47
Q

What is anaerobic respiration?
Why does it take place?
How does anaerobic respiration differ between yeast and other eukaryotic cells?

A
  • It is respiration in the absence of oxygen.
  • Lack of oxygen means that oxidative phosphorylation cannot take place and therefore the hydrogen carriers need to be regenerated in a different way.
  • Yeast cells: Alcoholic fermentation; Eukaryotic cells: Lactic fermentation
48
Q

What is alcoholic fermentation?
What are the stages and how do they happen?
Why is it not favourable?

A
  • It is anaerobic respiration when glucose is converted to ethanol and carbon dioxide.
  • Pyruvate is decarboxylated to ethanal and then ethanol. Ethanal is reduced to Ethanol using the H+ from the reduced NAD, regenerating the oxidised NAD.
  • toxic products, not reversible so chemical potential is wasted and no further ATP is produced.
49
Q

What are the products of alcoholic fermentation?

A
  1. Ethanol
  2. Carbon dioxide
  3. ATP
50
Q

What is lactic fermentation?
How does it happen?
Why is CO2 not produced?
When does it happen?

A
  • Respiration in which, in the absence of oxygen , glucose is converted to lactic acid.
  • The pyruvate is converted to lactate that regenerates the oxidised form of NAD so that glycolysis can continue
  • lactate is a 3 carbon sugar and so is pyruvate
  • During short bursts of vigorous contraction where lactate will accumulate in the muscles - extra oxygen is required to remove the lactate.
51
Q

Why does rice plants have to respire anaerobically?

A
  • Flooded fields have less oxygen which deprives the roots of oxygen. Oxygen diffuses slowly. Microorganisms also use up oxygen which reduces the oxygen concentration.
  • This causes them respire anaerobically producing ethanol which is toxic.
52
Q

What are the adaptations of rice to over come the lack of oxygen?

A
  • Plants grow taller to get more access to O2
  • Aerenchyma: loosely packed cells that allow the diffusion of gases to happen easily from the aerial regions
  • High levels of alcohol dehydrogenase: breaks down the ethanol
  • Tolerant to the ethanol that is lost to adventitious roots
  • Hydrophobic corrugated surface that holds a thin layer of air between the leaf structure.
53
Q

Compare the relative amounts of ATP produced when a molecule is completely oxidised in substrate-level phosphorylation and oxidative phosphorylation.

A

Oxidative phosphorylation is more than substrate-level phosphorylation
32/34 vs 4/6

54
Q

Explain why oxidative phosphorylation is not possible in the absence of oxygen.

A
  • Requires a proton gradient produced by the ETC
  • With no oxygen, ETC does not occur/no electron flow
  • NAD cannot be formed/ NADH cannot be reduced
  • Oxygen combines with the proton/electron/ is the final acceptor of the ETC.
55
Q

How might the RQ value change for seeds in the following conditions and Explain:

  1. Seeds soaked in water
  2. Seeds after 12 hrs in the soil
  3. seedlings after 21 days
A
  1. High RQ - Little oxygen in water so anaerobic respiration
  2. Low RQ - Mostly Aerobic respiration, so a mixture of substrates can be produced e.g proteins carbohydrates and lipids
  3. 1 - Aerobic respiration and the energy is stored as carbohydrates
56
Q

What are the typical energy values for Lipids, Proteins and carbohydrates?

A
  • Lipids: 39.4 KJg^-1
  • Protein: 17.0 KJg^-1
  • Carbohydrates: 15.8 KJg^-1
57
Q

What are the typical RQ values for Lipids, proteins and carbohydrates?

A

carbohydrate - 1
protein - 0.8 - 0.9
lipid - 0.7

58
Q

Explain why O2 consumptions in organisms increase as the temperature increases.

A
  • Metabolism is faster
  • molecules and enzymes have more kinetic energy
  • More frequent collisions
  • Production of reduced NAD takes place at a faster rate
  • increase in anabolic reactions
59
Q

Which part of the mitochondria is the electron transport chain found?

A

Inner membrane space

cristea

60
Q

Describe the role of oxygen in oxidative phosphorylation.

A
  • Final acceptor of electrons
  • So carrier can be reduced again
  • So electrons can keep flowing through ETC
  • Oxygen combines with H+ to form water
61
Q

Why is anaerobic respiration less efficient than aerobic respiration?

A
  1. Only 2 molecules of ATP produced per mol of glucose
    2 End product lactate sill has chemical potential energy
  2. Not sustainable
62
Q

What is Oxygen debt?

A

It is the additional oxygen required in the metabolic pathways involved in the conversion of lactate to glucose.

63
Q

Describe how the production of lactate in muscle tissue differed from anaerobic respiration in yeast?

A
  • No decarboxylation/ carbon dioxide removed
  • Single-step
  • Lactate dehydrogenase
  • Reversible
64
Q

How does anaerobic respiration differ between plants and animals?

A

in plants:

  • pyruvate is converted to ethanol
  • ethanal is reduced
  • by reduced NAD
  • ethanol formed

in animals

  • pyruvate converted to lactate
  • by reduced NAD
  • in liver/ muscles
  • allows glycolysis to continue
65
Q

What are the major products of Glycolysis, Krebs cycle and Oxidative phosphorylation?

A

Glycolysis
- Pyruvate - ATP - NADH

Krebs Cycle
- NADH & FADH - ATP - CO2

Oxidative Phosphorylation
- H2O - ATP - NAD/FAD

66
Q

Why is glucose phosphorylated in glycolysis?

A
  • hexoses are energy-rich
  • does not react easily
  • Phosphorylation activates hexose
  • Maintain concentration of glucose inside and outside the cell.
67
Q

Explain why ATP is able to transfer energy in cells.

A
  • Synthesized from ADP and Pi
  • soluble molecule
  • Diffuses slowly
  • on hydrolysis energy is released
  • intermediary between energy-yielding and energy-requiring reactions.
68
Q

Under which circumstances are amino acids broken down for energy?

A
  • During starvation/ lack of fat or carbohydrate
69
Q

What is the name of the enzyme responsible for the conversion of pyruvate to lactate?

A

lactate dehydrogenase

70
Q

How are the mitochondria adapted to carry out the processes of respiration?

A
  1. Membranes separate from the rest of the cytoplasm
  2. allows different pH
  3. inner membrane contains ATPase
  4. a linear arrangement of the ETC -> greater efficiency
  5. Folded cristae -> Higher surface area
  6. The Matrix contains enzymes
71
Q

What are some uses for the energy produced by ATP

A
  1. Muscle contraction
  2. Protein synthesis
  3. DNA Replication
  4. Cell movement
  5. Active transport
72
Q

Describe the structural features of ATP.

A
  1. a nucleotide
  2. with three phosphate groups
  3. an organic nitrogenous base - adenine
  4. a pentose sugar
  5. Ester linkages / covalent bonds
73
Q

Why cannot phosphorylated glucose not diffuse out of the cell?

A
  1. Cannot pass through the phospholipid bilayer
  2. No specific transport protein
  3. Used up as soon as it is produced
  4. Too big to fit through (glucose’s) protein channel
74
Q

What is the role of NAD?

A 
It is a coenzyme 
Hydrogen carrier
carries H from glycolysis/Krebbs cycle
to the electron transport chain
Involved in the oxidation of triose phosphate to  pyruvate
involved in anaerobic respiration

A Level Biology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions