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A2 OCR Biology F214 > Respiration > Flashcards

Flashcards in Respiration Deck (36)
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1
Q

Define respiration

A

The process of creating ATP from energy stored in complex organic molecules

2
Q

Define energy

A

The ability to do work

3
Q

Why do we need energy

A

All living organisms needs energy for their biological processes

4
Q

Identify 3 metabolic processes

A
  • Active transport of substances
  • Secretion
  • Endocytosis
  • Synthesis of large molecules
  • Replication of DNA
  • Movement
5
Q

What is a phototroph

A

An organism which uses sunlight energy to make organic molecules containing chemical potential energy

6
Q

What is ATP

A

Adenosine Triphosphate
A phosphorylated nucleotide
High energy compund
Universal energy currency

7
Q

What type of reaction can break down an ATP molecule

A

Hydrolysis

8
Q

What enzyme and products does the hydrolysis reaction of ATP use/produce

A

ATPsynthase or ATPase
ATP –> ADP + Pi
ADP +Pi –> ATP

9
Q

Define Coenzyme

A

A non-protein compound that is necessary for the functioning of an enzyme

10
Q

What are the 4 stages of respiration

A

Aerobic Glycolysis
The Link Reaction
Krebs Cycle
Oxidative Phosphorylation

11
Q

Where does each stage take place in the cell

A

Gly- cytoplasm
Link- mitochondria matrix
Krebs- mitochondria matrix
OP- folded inner membrane of mitochondria

12
Q

Why are co-enzymes needed

A

Needed to help with the redox reactions e.g. NAD - NADH

13
Q

Identify two co-enzymes used in respiration

A

NAD

Coenzyme A

14
Q

Briefly summarise glycolysis

A

The metabolic pathway where each glucose molecule is broken down into two molecules of pyruvate

15
Q

Describe the process of glycolysis

A
Glucose --> (ATP) 
Glucose-6-phosphate --> 
Fructose-1-phosphate --> (ATP) 
Hexose 1,6-bisphosphate --> 
2 x triose-phosphate --> (2ATP and 2NADH Produced)
2 x intermediaries --> (2ATP Produced) 
2 x pyruvate
16
Q

Define mitochondria

A

The site of the aerobic stages of respiration

17
Q

Describe the structure of a mitochondrion

A
  • Matrix
  • Intermembrane space
  • Cristae
  • Inner and Outer membrane (Envelope)
  • ATPsynthase
18
Q

What is chemiosmosis

A

The movement of ions across a selectively permeable membrane, down their electrochemical gradient

19
Q

Describe ATP synthesis in a mitochondrion

A
  1. The axle rotates the head
  2. ADP and Pi join to form ATP
  3. The section of the headpiece undergoes a conformational shape change and ATP is released
20
Q

Briefly summarise the link reaction

A

Pyruvate is converted to acetate.

NAD is reduced

21
Q

What are the 2 enzymes used in the link reaction

A

pyruvate dehydrogenase

pyruvate decarboxylase

22
Q

Briefly summarise the krebs cycle

A

Acetate oxidised to co2.
NAD and FAD are reduced.
ATP is produced.
Oxaloacetate is regenerated

23
Q

Describe the steps involved in the Krebs Cycle

A
  1. Acetate is offloaded from CoA and joins with Oxaloacetate to form citrate.
  2. Citrate is decarboxlyated and dehydrogenated to form a 5C compound.
    - The hydrogen atoms are accepted by NAD, which take them to the Electron Transport Chain
    - The Carboxyl group becomes CO2.
  3. The 5C compound is decarboxylated and dehydrogenated to form a 4C compound.
  4. The 4C compound is changed into another 4C compound, and a molecule of ATP is phosphorylated.
  5. The second 4C compound is changed into a third 4C compound and a pair of hydrogen atoms are removed, reducing FAD.
  6. The third 4C compound is further dehydrogenated to regenerate oxaloacetate
24
Q

How many turns of the krebs cycle is needed for each molecule of glucose?

A

2.
1 glucose = 2xpyruvate
2x pyruvate= 1 krebs

25
Q

Briefly summarise oxidative phosphorylation

A

The formation of ATP and water via the ETC and chemiosmosis

26
Q

Describe the Chemiosmosis process

A
  1. Reduced NAD and FAD donate hydrogen ions, which are split into protons and electrons
  2. The protons are pumped across the inner mitochondrial membrane
  3. The hydrogen ions diffuse through ATP synthase
  4. produces ATP
27
Q

Evidence for chemiosmosis

A
  • Researchers isolated mitochondria and treated them by placing them in a solution with a very low water potential.
  • This meant that the outer membrane ruptured, releasing the contents of the intermembrane space.
  • If they further treated these mitoblasts with a strong detergent, they could release the contents of the matrix.
  • ATP was also not made if the mushroom-shaped parts of the stalked particles were removed from the inner membrane of the intact mitochondria.
28
Q

Why is the ATP yield not always met

A
  • Some hydrogens leak across the mitochondrial membrane
  • Some ATP is used to actively transport pyruvate into the mitochondria.
  • Some ATP is used to bring Hydrogen from reduced NAD made during glycolysis
29
Q

Define anaerobic respiration

A

The release of energy from substrates such as glucose in the absence of oxygen

30
Q

What is the final electron acceptor in OP

A

oxygen

31
Q

Name the two methods of the reoxidisation of NAD

A

Lactate fermentation

Ethanol fermentation

32
Q

When would Lactate fermentation occur

A

Vigorous activity e.g. running

33
Q

Describe the process of lactate fermentation

A

Pyruvate accepts hydrogen atoms from NADH , which is reoxidised. 7
Pyruvate is reduced to lactate

34
Q

What happens to the lactate that has been produced

A

It is taken to the liver and then either:

  • converted into pyruvate
  • recycled to glucose/glycogen
35
Q

Describe the process of ethanol fermentation

A

Pyruvate is decarboxylated to ethanal. Ethanal accepts hydrogen atoms from NADH, which is reoxidised. Ethanal is reduced to ethanol.

36
Q

Name the three enzymes involved in fermentation reactions

A

Pyruvate decarboxylase
Ethanol dehydrogenase
Lactate dehydrogenase