2.8 Flashcards

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1
Q

Cell respiration

A

Cell respiration is the controlled release of energy from organic compounds to produce ATP

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2
Q

Main organic compound used in cell respiration

A

The main organic compound used for this process is carbohydrates (glucose), although lipids and proteins can also be digested

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3
Q

There are two main types of cell respiration:

A

Anaerobic and Aerobic

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4
Q

Anaerobic cell respiration

A

Anaerobic respiration involves the partial breakdown of glucose in the cytosol for a small yield of ATP

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5
Q

Aerobic cell respiration

A

Aerobic respiration utilises oxygen to completely break down glucose in the mitochondria for a larger ATP yield

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6
Q

ATP (adenosine triphosphate) is…

A

a high energy molecule that functions as an immediate source of power for cell processes

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7
Q

One molecule of ATP contains three…

A

covalently linked phosphate groups – which store potential energy in their bonds

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8
Q

When ATP is hydrolysed it forms?

A

ADP + Pi, the energy stored in the phophate bond is released to be used by the cell

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9
Q

Cell respiration uses energy stored in…

A

organic molecules to regenerate ATP from ADP + Pi (via oxidation)

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10
Q

glycolysis

A

glycolysis begins with the anaerobic breakdown of glucose in the cytosol. Both anaerobic and aerobic respiration pathways begin with this.

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11
Q

Glycolysis breaks down glucose (6-C) into

A

two molecules of pyruvate (3C), and also produces:

  • Hydrogen carriers (NADH) from an oxidised precursor (NAD+)
  • A small yield of ATP (net gain of 2 molecules)
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12
Q

Anaerobic respiration proceeds in the absence of…

A

oxygen and does not result in the production of any further ATP molecules

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13
Q

pyruvate in animals

A

In animals, the pyruvate is converted into lactic acid (or lactate)

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14
Q

pyruvate in plants and yeast

A

In plants and yeasts, the pyruvate is converted into ethanol and carbon dioxide

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15
Q

The purpose of anaerobic respiration is to…

A

restore stocks of NAD+ – as this molecule is needed for glycolysis
- By restoring stocks of NAD+ via anaerobic pathways, the organism can continue to produce ATP via glycolysis

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16
Q

The conversion of pyruvate into lactic acid (animals) or ethanol and CO2 (plants / yeasts) is…

A

reversible

- Hence, pyruvate levels can be restored once oxygen is present and a greater yield of ATP may be produced aerobically

17
Q

Muscle contractions…

A

require the expenditure of high amounts of energy and thus require high levels of ATP

18
Q

When exercising at high intensity, the cells’ energy demands will exceed what the available levels of O2 can supply aerobically. Hence…

A

the body will begin breaking down glucose anaerobically to maximise ATP production

19
Q

exercising at high intensity will result in an…

A

increase in the production of lactic acid, which leads to muscle fatigue
- When the individual stops exercising, oxygen levels will increase and lactate will be converted back to pyruvate

20
Q

what will undergo anaerobic respiration?

A

Although carbohydrates, lipids and proteins can all be consumed as energy sources, only carbohydrates will typically undergo it.

21
Q

how do the conditions of cell respiration change with increasing energy demand?

A
  • At high intensities, the aerobic consumption of fats is decreased while the anaerobic consumption of sugars increases
  • Consequently, lactate levels will increase at higher levels of exercise intensity
22
Q

Aerobic cell respiration requires…

A

the presence of oxygen and takes place within the mitochondrion

23
Q

Pyruvate is broken down into…

A

carbon dioxide and water, and a large amount of ATP is produced (~34 – 36 molecules)

24
Q

Although aerobic respiration typically begins with glycolysis in carbohydrates…

A

glycolysis itself is an anaerobic process

25
Q

Aerobic respiration consists of…

3 things

A

the link reaction, citric acid cycle (or Krebs cycle) and the electron transport chain

26
Q

Anaerobic respiration (fermentation) involves the…

A

breakdown of carbohydrates in the absence of oxygen

27
Q

In yeasts, fermentation results in the production of…

A

ethanol and carbon dioxide – which can be used in food processing:

28
Q

Role of yeast in bread

A

Carbon dioxide causes dough to rise (leavening), the ethanol evaporates during baking

29
Q

Role of yeast in alcohol

A

Ethanol is the intoxicating agent in alcoholic beverages (concentrations above ~14% damage the yeast)

30
Q

Bacterial cultures can also undergo fermentation to produce a variety of food products

A

Yogurt / Cheese – Bacteria produce lactic acid anaerobically, which modifies milk proteins to generate yogurts and cheeses

31
Q

A respirometer is…

A

a device that determines an organism’s respiration rate by measuring the rate of exchange of O2 and CO2

32
Q

Factors which may affect respiration rates include…

A

temperature, hydration, light (plants), age and activity levels

33
Q

An increase in carbon dioxide levels will indicate an…

A

increase in respiration (CO2 is a product of aerobic respiration)

34
Q

A decrease in oxygen levels will indicate an…

A

increase in respiration (O2 is a requirement for aerobic respiration)

35
Q

Carbohydrates are preferable as a ready-made energy source because:

A
  • They are easier to transport and digest (unlike lipids)

- They don’t produce nitrogenous wastes (unlike proteins)

36
Q

Carbohydrates can be broken down into…

A

monosaccharides (e.g. glucose), which are able to be used in glycolysis

37
Q

Lipids (i.e. triglycerides) can be broken down into…

A

glycerol and fatty acids, which are able to be used in aerobic respiration

38
Q

Proteins can be broken down into…

A

amino acids, which are also capable of being used in aerobic respiration

39
Q

There are several key differences between anaerobic and aerobic respiration, including:

A
  • Overall energy yield
  • Products formed
  • Location of processes