Brainscape's Knowledge GenomeTM

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


See full index

Undeleted > Respiration > Flashcards

Respiration Flashcards

1
Q

What are the four stages of respiration?

A

Glycolysis, Link reaction, Krebs Cycle, Oxidative phosphorylation.

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

What is Glycolysis?

A

Splitting of the 6-carbon glucose molecule into two 3-carbon pyruvate molecules.

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

What is the Link reaction?

A

The 3 - Carbon pyruvate molecules enter into a series of reactions which lead to the formation of acetylcoenzyme A, a two carbon molecule.

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

What is Kreb’s cycle?

A

The introduction of acetylcoenzyme A into a cycle of oxidation-reduction reactions that yield some ATP and a large quantity of reduced NAD and FAD.

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

What is Oxidative phosphorylation?

A

The use of the electrons, associated with reduced NAD and FAD, released from the Krebs cycle to synthesise ATP with water produced as a by-product.

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

True or false: Glycolysis is the initial stage of both anaerobic and aerobic respiration?

A

True

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

Where does Glycolysis occur?

A

The cytoplasm of all living cells.

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

What happens to carbon molecules in Glycolysis?

A

Hexose (6 carbon molecule) sugar is split into two molecules of pyruvate (3 carbon molecule).

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

What are the four enzyme controlled reactions in Glycolysis?

A

Glycolysis

  1. Phosphorylation of glucose to glucose phosphate - Glucose is made more reactive by the addition of two phosphate molecules. Phosphate molecules from hydrolysis of two ATP molecules > ADP. Provides energy to activate glucose and lowers activasion energy for enzyme controlled reactions.
  2. Splitting of the phosphorylated glucose - Each glucose molecule is split into two triosphosphate molecules (3-carbon molecules).
  3. Oxidation of triose phosphate - Hydrogen removed from each of the triose phosphate molecules and transferred to a hydrogen carrier molecule NAD to form reduced NAD.
  4. Production of ATP - Enzyme controlled reactions convert each triose phosphate into another 3-carbon molecule called pyruvate. In the process, two molecules of ATP are regenerated from ADP.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the yield from one glucose molecule undergoing glycolysis?

A
  • Two molecules of ATP (as two were used to phosphorylate glucose).
  • Two molecules of reduced NAD
  • Two molecules of pyruvate.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does Glycolysis provide indirect evidence for evolution?

A

Glycolysis provides indirect evidence for evolution because, enzymes for the glycolytic pathway are found in the cytoplasm of cells. So glycolysis does not require any organelles or membranes for it to take place.

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

What needs to happen for Glycolysis to continue?

A

In absence of oxygen the pyruvate produced by glycolysis can be converted into either lactate or ethanol during anaerobic respiration. This is necessary in order to re-oxidise NAD so that glycolysis can continue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Whats the problem with pyruvate molecules and Anaerobic repiration?

A

Anaerobic repiration yields only a small fraction of the potential energy stored in the pyruvate molecule. In order to release the remainder of this energy most organisms use oxygen to break down pyruvate further.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to pyruvate molecules during the link reaction?

A

They are oxidised.

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

Where do the Krebs cycle and Link reaction take place in eukaryotic cells?

A

In the mitochondria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do the pyruvate molecules get to the mitochondria for the Link reaction?

A

After glycolysis, Pyruvate molecules are actively transported to the matrix of the mitochondria.

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

What happens to pyruvate during the Link reaction?

A
  • Pyruvate oxidised to acetate.
  • 3-carbon pyruvate loses a CO2 molecule and two Hydrogens.
  • Hydrogens accepted by NAD to form reduced NAD.
  • Now 2-carbon acetate combines with a coenzyme A to produce a compund called acetylcoenzyme A.

Equation: Pyruvate + NAD + CoA > Acetyl CoA + reduced NAD + CO2

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

Who is the Kreb’s cycle named after?

A

Hans Krebs

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

What is the Kreb’s cycle a series of? And where?

A

Series of oxidation-reduction reactions so redox reactions, in mitochondria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Whats the process of the Kreb’s cycle?

A
  • (2-carbon compound) acetylcoenzyme A from link reaction, combines with a 4-carbon molecule to form a 6-carbon molecule.
  • Due to a series of reactions, 6-carbon molecule loses CO2 and hydrogen to produce a 4-carbon molecule and a single molecule of ATP, produced as a result of substrate-level phosphorylation.
  • The 4-carbon molecule can now combine with a new molecule of acetylcoenzyme A to begon the cycle again.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

For each molecule of pyruvate what is the yield from the link reaction and Kreb’s cycle? And what is it’s rule?

A
  • Reduced coezymes such as NAD Aand FAD, these are important products of kreb’s cycle as they can provide energy to produce ATP molecules by oxidative phosphorylation.
  • One molecule of ATP
  • Three molecules of CO2

Since 2 pyruvate molecules are made from a glucose molecule, actual yield above is mutiplied by two.

22
Q

Why are co-enzymes important in photosynthesis and respiration? Give examples.

A

They carry hydrogen atoms from one molecule to another. E.g.

  • NAD in respiration
  • FAD in Kreb’s cycle
  • NADP in photosynthesis
23
Q

Why is NAD the most important carrier in respiration?

A

It works with dehydrogenase enzymes that catalyse the removal of hydrogen atoms from substrates and transfer them to other molecules involved in oxidative phosphorylation.

24
Q

Why is the Kreb’s cycle important to organism’s cells?

A
  • It breaks down macromolecules into smaller ones E.g. Pyruvate is broken doen into CO2.
  • It produces hydrogen atoms carried by NAD to the electron transfer chain and provides energy for oxidative phosphorylation. This leads to the production of ATP that provides metabollic energy for the cell.
  • It regenerates a 4-carbon molecule that combines with acetlycoenzyme A which would otherwise accumulate.
  • It is a source of intermediate compounds used by cells to synthesise important substances e.g. fatty acids, amino acids and chorophyll.
25
Q

What is Oxidative phosphorylation?

A

Where some of the energy of electrons in hydrogen atoms is conserved as ATP.

26
Q

Why does oxidative phosphorylation take place in the cristea of the mitochondria?

A

In cristae (inner folded membrane) of mitochondria are enzymes and other proteins involved in oxidative phosphorylation and hence ATP synthesis.

27
Q

Why are there many mitochondria in metabolically active cells?

A

They play a vital role in respiration e.g. muslces, liver epithelial cells which carry out active transport.

28
Q

How are mitochondria in metabolically active cells adapted for oxidative phosphorylation?

A

Mitochondria in metabolically active cells have more densely packed cristae so a greater surface area of membrane incorperating enzymes and other proteins in oxidative phosphorylation.

29
Q

How is ATP synthesised by oxidative phosphorylation?

A

Transfer of electrons down a series of electron carrier molecules so an electron transfer chain.

30
Q

What is the process of ATP getting synthesised by oxidative phosphorylation?

A
  • Hydrogen atoms produced during glycolysis and Kreb’s cycle combine with NAD and FAD.
  • Reduced NAD and FAD donate electrons of hydrogen atoms they are carrying to first carrier molecule in electron transfer chain.
  • Electrons pass along a transfer chain of electron carrier molecules in a series of oxidation-reduction reactions. As electrons go along the chain the energy they release causes actie transport of hydrogen protons across inner mitochondrial membrane and into inter-membranal space.
  • The protons accumulate in the inter-membranal space before they diffuse back into the mitochondrial matrix through ATP synthase channels embedded in the inner mitochondrial membrane.
31
Q

Why is oxygen important in respiration?

A

It’s the final acceptor of hydrogen atoms produced in glycolysis and Kreb’s cycle. Without it removing hydrogen atoms at the end of the tranfer chain the hydrogen ions and electrons would back up along the chain and respiration would stop.

32
Q

Why are electrons carried by NAD and FAD not transferred in one step?

And how are they transferred?

A

When energy is released a little at a time more of it can be harvisted for the benefit of the organism.

For this reason electrons carried by carried by NAD and FAD are not tranferred in one step.

Instead they are passed along a series of electron carrier molecules each of which has a slightly lower energy level. The electrons therefore move down an energy gradient which allows the energy to be released gradually so more usefully.

33
Q

How do lipids contribute to respiration?

A

Before respiration, lipids are first hydrolysed to glycerol and fatty acids.

Glycerol is then phosphorylated and converted to triose phosphate which enters the Kreb’s cycle.

Fatty acid component is broken down into 2-carbon fragments which are converted to acetylcoenzyme A. This enters the Kreb’s cycle.

When lipids are oxidised they produce 2-carbon fragments of carbohydrate and many hydrogen atoms. The hydrogen atoms are used to produce ATP in oxidative phosphorylation. Due to this lipids release double the energy than the same mass of carbohydtrate.

34
Q

How do proteins contribute to respiration?

A

Proteins are hydrolysed into their constituent amino acids.

They have their amino group removed (daemination) before entering the respiratory pathway at different points depending on the amount of carbon they contain.

3-carbon compounds are converted to pyruvate, while 4 and 5-carbon compounds are converted to intermediates in the Kreb’s cycle.

35
Q

Why can’t the the Kreb’s cycle or electron transfer chain continue when there’s no oxygen?

A

Eventually all FAD and NAD will be reduced. No FAD or NAD will be avaliable to take up H+ produced in Kreb’s cycle so enzymes stop working.

This leaves only the anaerobic process of glycolysis as a potential source of ATP.

36
Q

How is glycolysis a continueous process?

A

Pyruvate and hydrogen are constantly removed. In particular hydrogen must be released form reduced NAD in order to regenerate NAD.

Without this, all NAD in cells will be converted to reduced NAD, leaving no NAD to take up the hydrogen produced from glycolysis.

So glycolysis will stop.

37
Q

How is NAD replenished?

A

NAD is replenished when pyruvate from glycolysis accepts hydrogen from reduced NAD. The oxidised NAD produced can then be used in further glycolysis.

38
Q

What two types of anaerobic respiration occur in eukaryotic cells?

A
  • Plants and microorganisms e.g. yeast - Pyruvate converted to ethanol and CO2
  • Animals - pyruvate converted to lactate.
39
Q

Give examples of plants and microorganisms that would produce ethanol.

A

Bacteria, fungi, (yeast), root cells under waterlogged conditions.

40
Q

How is ethanol produced by pyruvate? Also give the equation.

A

Pyruvate molecule formed at the end of glycolysis loses a CO2 molecule and accepts hydrogen from reduced NAD to produce ethanol.

Pyruvate + reduced NAD > Ethanol + CO2 + oxidised NAD

41
Q

What is a common use for yeast by humans?

A

Anaerobic respiration in yeast used in brewing industry as ethanol is used.

Yeast grown in anaerobic conditions where it ferments natural carbohydrates in plant products e.g. grapes (wine) barely seeds (beer) into ethanol.

42
Q

Where does prodution of lactate in animals mainly occur?

A

Mostly in muscles after streneous exercise.

43
Q

What happens when lactate needs to be produced?

A

In these conditions oxygen is used more quickly than its supplied so an oxygen debt is created. But essential muscles keep working e.g. fleeing a predator.

When oxygen is in short supply, NAD from glycolysis accumulates and must be removed. To achieve this, each pyruvate molecule produced, takes up two hydrogen atoms from reduced NAD produced in glycolysis to form lactate.

Pyruvate + reduced NAD > Lactate + oxidised NAD.

44
Q

What happens to lactate after the oxygen debt is overcome?

A

Lactate produced is oxidised back into pyruvate. Where it can either be further oxidised to release energy or converted into glycogen.

45
Q

What does a build up of lactate cause?

A

Cramp, muscle fatigue when it accumulates in muscle tissue.

As its an acid it causes PH changes effecting enzymes.

46
Q

Where is? And what is lactate converted into?

A

Lactate is taken to the liver to be converted to glycogen.

47
Q

In what two ways in energy from cellular respiration derived?

A
  • Substrate-level phosphorylation in glycolysis an Kreb’s cycle. Direct transfer of phosphate from a respiratory intermediate to ADP to produce ATP.
  • Oxidative phosphorylation in the electron tranfer chain. Indirect linking of energy from phosphate to ADP to produce ATP, involving energy from the hydrogen atoms that are carried on NAD and FAD. Cells produce most of their ATP this way.
48
Q

True or false: As in aerobic respiration pyruvate is converted to eother ethanol or lactate. It is not avaliable in kreb’s cycle. No in aerobic respiration neither Kreb’s cycle nor the electron transfer chain take place. Only ATP produced in anaerobic respiration is therefore formed by glycolysis.

A

True.

49
Q

What is the investigation using cyanide to determine locations of respiratory pathways in cells?

A

Cyandide deady as its a non-competetive inhibitor of final enzyme in electron transfer chain.

Enzyme called cytochrome oxidase, catalyses the addition of the hydrogen ions and electrons to oxygen to form water.

Inhibation of cytochrome oxidase causes hydrogen ions and electrons to accumulate on their molecules, bringing the electron transport chain and Kreb’s cycle to a halt.

50
Q

What is the process of the investigation using cyanide to determine locations of respiratory pathways in cells?

A
  • Mammalian liver cells were broken up (homogenised) and the resulting homogenate was centrifuged.
  • Portions containing only nuclei, ribosomes, mitochondria and removing cytoplasm were seperated out.
  • Samples of each portion, and of the complete homogenate, were incubated as follows,
  • with glucose
  • with glucose and cyanide
  • with pyruvate and cyanide
  • with pyruvate

After incubation, the presence or absence of carbon dioxide and lactate in each sample was recorded.

Undeleted (17 decks)

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