2.8 Cell Respiration

Question 1

In cell respiration in plants and humans, what organic compounds are used and where are they obtained from?

Answer 1

• In humans, carbohydrates and lipids are used, but if we consume more proteins than needed, amino acids from proteins may be used
• In plants, carbohydrates or lipids are used, which is made from photosynthesis

Question 2

What is cell respiration?

Answer 2

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

Question 3

The energy released during cell respiration is retained in what usable form?

Answer 3

Adenosine triphosphate (ATP)

Question 4

How do you make ATP?

Answer 4

Phosphate group linkage to to adenosine diphosphate (ADP).
- Energy is needed for this reaction to be carried out, which comes from breakdown of organic compounds

Question 5

Briefly explain why cell respiration is an essential function of life in all cells.

Answer 5

• to generate usable ATP energy in order to support many other reactions in the cell

Question 6

What 3 main activities does cells require energy for?

Answer 6

1. Synthesizing lareg molecules like DNA, RNA and proteins
2. Pumping molecules or ions across membranes by active transport
3. Moving things around inside the cell, such as chromosomes, vesicles etc.

Question 7

What is the advantage of ATP as an energy supply?

Answer 7

• energy is immediately available
• released by splitting ATP into ADP + phosphate
• ADP + phosphate can be reconverted back to ATP by cell respiration

Question 8

What is the reason for cells requiring a continual source of ATP for cell activities?

Answer 8

When energy from ATP is used in cells it is all converted to heat energy and while this can help in keeping an organism warm, it cannot be reused for cell activities, resulting in this heat energy to eventually be lost to the environment.

Question 9

What is anaerobic respiration?

Answer 9

• Respiratory process that occurs in both prokaryotes and eukaryotes
• Glucose is broken down without the use of oxygen
• Small yield of ATP, but quick production of ATP

Question 10

In what 3 situations is anaerobic cell respiration useful in?

Answer 10

1. When a short but rapid burst of ATP production is needed
2. When oxygen supplies run out in respiring cells
3. In environments that are deficient in oxygen (eg. waterlogged soils)

Question 11

Explain anaerobic respiration in humans, yeast and plants.

Answer 11

• In humans, Glucose is converted to lactic acid, usually in dissolved form of lactate
• In yeast and plants, Glucose is converted to carbon dioxide and ethanol
• Lactate and ethanol is toxic in excess, so must be removed from the cells that produce them, or be produced in limited quantities

Question 12

Explain the use of anaerobic cell respiration in yeasts to produce ethanol and carbon dioxide in baking.

Question 13

Explain lactate production in humans when anaerobic respiration is used to maximize the power of muscle contractions.

Question 14

What is aerobic cell respiration?

Answer 14

In the presence of oxygen, glucose is more fully broken down to release a large yield of ATP from glucose

Question 15

What are the series of chemical reactions of aerobic cell respiration?

Answer 15

• glucose + oxygen = carbon dioxide + water
• carbon dioxide is the waste product in most organisms while water is useful
• in eukaryotic cells, most reactions happen inside the mitochondrion

Question 16

What is a respirometer?

Answer 16

a device that is used to measure respiration rate

Question 17

What are the parts of a respirometer?

Question 18

Explain how a respirometer works.

Question 19

What experiments can a respirometer be used in?

Question 20

How to analyze readings of a repirometer?

Question 21

What are the ethical implications of using invertebrates in respirometer experiments?