Bio-energetics

Question 1

Factors affecting rate of photosynthesis

Answer 1

Light intensity
Temperature - enzymes work quicker (up to a point), molecules move faster
Amount of chlorophyll
Carbon dioxide concentration

Question 2

5 things plants use glucose for

Answer 2

Respiration - provide energy to cells
Cellulose cell walls - protect, maintain structure
Energy storage as starch for times with less photosynthesis (winter)
Energy as fats and oils for storage in seeds
Making amino acids (combined with nitrates)

Question 3

3 uses of respiration

Answer 3

Energy to cells needed for all living processes

Building larger molecules from smaller ones (eg proteins from amino acids)

Increasing body temperature (in mammals and birds) to stay warm

Question 4

What is metabolism?
What controls most of these?

Answer 4

All the chemical processes that occur within a living organism in order to maintain life.

Enzymes control most of these reactions, and many of them are linked together to form bigger reactions.

Question 5

2 negatives of anaerobic respiration

Answer 5

It creates a buildup of lactic acid (painful)

Incomplete breakdown of glucose so less efficient for energy, and muscles become fatigued

Question 6

Give 3 examples of where energy from respiration is used to create larger molecules

Answer 6

Glucose is joined together to form glycogen
Glucose joined to form starch
Glucose with nitrates to form amino acids (to form proteins)

Question 7

2 examples of large molecules being broken down

Answer 7

Glucose for respiration
Glycogen to glucose
Excess amino acids to urea

Question 8

How does the body remove lactic acid from the muscles after exercise?

Answer 8

Breathing in extra oxygen - heavy breathing (oxygen debt)

Oxygen reacts with the lactic acid to turn it into water and carbon dioxide

Blood carries lactic acid to liver
Where it is converted to glucose

(Requires oxygen)

Question 9

What is meant by muscles becoming fatigued?

Answer 9

Muscles can no longer contract efficiently.

Question 10

How does the body respond to exercise

Answer 10

Increased breathing rate and breath volume

Increased heart rate to increased bloow flow with the extra oxygen to muscles

Question 11

How do you measure the rate of photosynthesis (2 mark question)

Answer 11

Measure volume of gas in a given time

Question 12

Compare anaerobic respiration in a yeast cell to in a muscle cell

Answer 12

In a yeast cell ethanol is produced but in a muscle cell lactic acid is produced

In a yeast cell carbon dioxide is produced but in a muscle cell no carbon dioxide is produced

Both dont release much energy

must be comparative

Question 13

Explain how more blood flow to muscles makes it easier for the athlete to run

Answer 13

More blood flow to muscles means more oxygen and glucose delivered to muscles.

This means more respiration

So more energy for the muscles to contract efficiently

(Not required) minimises anaerobic respiration