Combined Biology - 4.4 Flashcards Preview

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Flashcards in Combined Biology - 4.4 Deck (29)
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1
Q

Write the word and symbol equations for photosynthesis.

A

carbon dioxide + water → glucose + oxygen

6CO2 + 6H2O → C6H12O6 + 6O2

2
Q

Why is photosynthesis described as an endothermic reaction?

A

Energy is transferred from the environment to the chloroplasts, by light.

3
Q

Name four factors that affect the rate of photosynthesis.

A
  • Temperature
  • Light intensity
  • Carbon dioxide concentration
  • Amount of chlorophyll
4
Q

Higher Q. Describe how both temperature and light intensity affect the rate of photosynthesis.

*this is just an example, you have to be able to do this for any graph with interacting limiting factors

A
  • As light intensity increases, the rate of photosynthesis increases, for both lines.
  • When light is no longer a limiting factor, the lines level off.
  • Temperature must have been a limiting factor at 10 oC as 20 oC levels off higher than 10 oC.
5
Q

Higher Q. Suggest ways in which gardeners can optimise conditions for photosynthesis in greenhouses.

A
  • Heater – to increase temperature (e.g. in winter)
  • Shade/ventilation/opening windows – to decrease temperature (e.g. in summer)
  • Artificial lights – to increase light intensity
  • Paraffin heaters – to increase both temperature and carbon dioxide levels
6
Q

List the 5 ways that plants use the glucose produced in photosynthesis.

A
  • Respiration
  • Converted into insoluble starch for storage
  • Used to produce fat or oil for storage
  • Used to produce cellulose, which strengthens the cell wall
  • Used to produce amino acids for protein synthesis
7
Q

As well as glucose, what else do plants need to produce proteins?

A

Nitrates (that they absorb from the soil)

8
Q

Higher Q. Use the inverse square law to calculate the light intensity when a lamp is placed 20 cm from some pond weed.

*This is just an example, you will need to be able to do this calculation when given the appropriate information.

A

Use the equation: light intensity ∝ 1/(distance (d)2)

Light intensity = 1/(20)2

Light intensity = 0.0025 arbitrary units

9
Q

Is respiration an endothermic or exothermic reaction?

A

Exothermic reaction

10
Q

Q. Which type of respiration releases most energy?

Q. Which type of respiration requires oxygen?

A
  • Aerobic Respiration
  • Aerobic Respiration
11
Q

List three things that organisms need the energy from respiration for.

A
  • Chemical reactions to build larger molecules
  • Movement
  • Keeping Warm
12
Q

Write the word and symbol equations for aerobic respiration.

A

glucose + oxygen → carbon dioxide + water

C6H12O6 + 6O2 → 6CO2 + 6H2O

13
Q

Write the word equation for anaerobic respiration in muscles.

A

glucose → lactic acid

14
Q

Write the word equation for anaerobic respiration in plant and yeast cells.

A

glucose → ethanol + carbon dioxide

15
Q

Name the process of anaerobic respiration in yeast cells.

A

Fermentation

16
Q

Give the two main industrial uses of fermentation.

A

Bread making and alcoholic drinks

17
Q

Explain how the human body reacts to the increased demand for energy during exercise.

A
  • Heart rate increases
  • Breathing rate increases
  • Breath volume increases
  • So the muscles receive more oxygenated blood
18
Q

What type of respiration takes place if there is an insufficient amount of oxygen?

A

Anaerobic Respiration

19
Q

What type of respiration involves the incomplete oxidation of glucose?

A

Anaerobic Respiration

20
Q

What happens to muscles after long periods of exercise?

A
  • There is a build up of lactic acid.
  • This causes oxygen debt.
  • The muscles become fatigued.
  • Muscles stop contracting efficiently.
21
Q

Higher Q. How do the muscles get rid of excess lactic acid?

A
  • Blood transports lactic acid to liver.
  • In the liver lactic acid is converted back into glucose.
22
Q

Higher Q. What is ‘oxygen debt’?

A

Oxygen debt is the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells.

23
Q

What is ‘metabolism’?

A

The sum of all chemical reactions in a cell or the body.

24
Q

List 5 processes involved in metabolism.

A
  • Conversion of glucose to starch, glycogen and cellulose.
  • Formation of lipid molecules from one molecule of glycerol and three molecules of fatty acids.
  • Making amino acids (then proteins) using glucose and nitrate ions.
  • Respiration
  • Breakdown of excess proteins to form urea for excretion.
25
Q

Sketch a graph to show how light intensity affects the rate of photosynthesis

A
26
Q

Sketch a graph to show how carbon dioxide affects the rate of photosynthesis.

A
27
Q

Sketch a graph to show how temperature affects the rate of photosynthesis.

A
28
Q

Why does temperature affect the rate of photosynthesis?

A
  • Because enzymes are needed for photosynthesis to work.
  • There is an optimum temperature for the enzymes to work at.
  • If the temperature is too low, the enzymes will work too slowly.
  • If the temperature is too high, the enzymes will denature and not work.
29
Q

Describe how you would use the following equipment to investigate how light intensity affects the rate of photosynthesis.

A
  • Measure ‘10’ cm from pondweed using ruler and place lamp here.
  • Turn lamp on and count the number of bubbles produced in one minute (or attach gas syringe and measure the volume of gas produced per minute).
  • Repeat 2 more times at this distance.
  • Repeat for different distances of lamp to pondweed (e.g. 5 cm, 15 cm, 20 cm).