Topic 4-Bioenergetics Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Where does photosynthesis take place

A

In the chloroplasts in green plant cells. They contain pigments like chlorophyll which absorb light

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

How is energy transferred to the chloroplasts from the environment

A

By light

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

Is photosynthesis endothermic or exothermic

A

Endothermic

This means that energy is transferred from the environment in the process

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

Word equation for photosynthesis

A

Carbon dioxide + water —-> (light) glucose + oxygen

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

Symbol equation for photosynthesis

A

6CO2 + 6H2O ——> (light) C6H12O6 + 6O2

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

Plants use glucose in 5 main ways

•For respiration

A

This transfers energy from glucose which enables the plants to convert the rest of the glucose into various other useful substances

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

Plants use glucose in 5 main ways

•Making cellulose

A

Glucose is converted into cellulose for making strong plant cell walls

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

Plants use glucose in 5 main ways

•Making amino acids

A

Glucose is combined with nitrate ions (absorbed from the soil) to make amino acids, which are then made into proteins

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

Plants use glucose in 5 main ways

•Stored as oils or fats

A

Glucose is turned into lipids (fats and oils) for storing in seeds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Plants use glucose in 5 main ways

•Stored as starch

A

Glucose is turned into starch and stored in roots, stems and leaves, ready for use when photosynthesis isnt happening, like in winter. Starch is insoluble which makes it much better for storing than glucose-a cell with lots of glucose in would draw in loads of water and swell up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The limiting factors that affect rate of photosynthesis are

A
  • light
  • temperature
  • amount of carbon dioxide
  • amount of chlorophyll
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Effects of light on rate of photosynthesis

A

Light provides the energy needed for photosynthesis.
As the light level is raised, the rate of photosynthesis increases steadily but ot up to a certain point (the optimum).
Beyond that, light wont make any difference because it will be either co2 or temperature that is the limiting factor

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

Effects of carbon dioxide levels on rate of photosynthesis

A

CO2 is one of the raw materials needed for photosynthesis.
The amount of CO2 will only increase the rate of photosynthesis up to a certain point (the optimum). After this CO2 is no longer a limiting factor

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

Effects of temperature on rate of photosynthesis

A

Temperature affects the rate of photosynthesis because it affects the enzymes involved
Usually if temp is the limiting factor its because it is too low (enzymes work slower at low temps). But if the plant gets too hot the enzymes will be damaged. This happens at about 45 degrees

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

Required practical:
Oxygen production shows the rate of photosynthesis
(The pondweed one)

A
  1. Source of light placed specific distance from pondweed
  2. Pondweed is left to photosynthesise for a set length of time. Oxygen produced will collect in capillary tube
  3. At the end, use syringe to draw gas bubbles up tube along a ruler and measure length of bubble. This is proportional to volume of O2 produced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Required practical:
Oxygen production slows the rate of photosynthesis
(The pondweed one)
PART 2

A
  1. Variables should be controller e.g temperature and time to photosynthesise
  2. Repeat twice with light at same distance and calculate a mean
  3. Repeat whole experiment with light source at different distances from pondweed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The inverse square law links light intensity and distance

EQUATION

A

Light intensity (is proportional to/fish thing) 1
——
Distance squared

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

The inverse square law links light intensity and distance

Explanation

A

As the distance increases the light intensity decreases. Light intensity is in proportion to the square of the distance (inverse square law). If you halve the distance the light intensity will be 4 times bigger
Use 1/d(squared) to measure light intensity

19
Q

The most common way to artificially create the ideal environment for plants to grow

A

In a greenhouse

20
Q

How greenhouses use heat

A

Greenhouses help trap the suns heat, and make sure temperature doesn’t become limiting. In winter a farmer may use a heater as well to keep temperature at ideal level. In summer it could get too hot so they may use shades and ventilation to cool it down

21
Q

How greenhouses use light

A

Light is always needed for photosynthesis so commercial farmers often supply artificial light after the sun goes down to give their plants more time to photosynthesise

22
Q

How carbon dioxide is used in greenhouses

A

Farmers can also increase the level of carbon dioxide in the greenhouse. A fairly common way is to use a paraffin heater to heat the greenhouse. As thr paraffin burns it produces carbon dioxide as a by product.

23
Q

How enclosure is used in greenhouses

A

Keeping plants enclosed in a greenhouse also makes it easier to keep them free from pests or diseases. The farmer can also add fertilisers to the soil to provide all the minerals needed for healthy growth

24
Q

Results of using a greenhouse

A

If the farmer can keep the conditions just right the plants will grow faster and a decent crop can be harvested more often which can then be sold to make profit.

25
Q

Respiration (definition)

A

Respiration is the process of transferring energy from glucose which goes in every cell

26
Q

Is respiration endothermic or exothermic

A

Exothermic, it transfers energy to the environment

27
Q

How can energy transferred by respiration be used

A
  1. To build up larger molecules from smaller ones (eg proteins from amino acids)
  2. In animals, to allow the muscles to contract for movement
  3. In mammals and birds to keep their body temperature steady in colder surroundings
28
Q

Metabolism

A

Metabolism is all the chemical reactions in an organism

29
Q

The sum of all the reactions in the body is metabolism (example)

A

In some of the reactions, larger molecules are made from smaller ones EG: Glucose is combined with nitrate ions to make amino acids then proteins
In other reactions, larger molecules are broken down into smaller ones EG: Excess protein is broken down in a reaction to produce urea

30
Q

Aerobic respiration

A

Respiration using oxygen

31
Q

Where does aerobic respiration occur

A

Most of the reactions in aerobic respiration happen inside the mitochondira

32
Q

Word equation for aerobic respiration

A

Glucose + oxygen —-> carbon dioxide + water

33
Q

Symbol equation for aerobic respiration

A

C6H12O6 + 6O2 ——> 6CO2 + 6H2O

34
Q

Anerobic respiration

A

Respiration without oxygen

35
Q

Word equation for anaerobic respiration

A

Glucose—-> lactic acid

36
Q

Anaerobic respiration is plants and yeast cells

A

Anaerobic respiration in yeast cells is called fermentation. Fermentation by yeast can be used to make bread and alcoholic drinks.

37
Q

Anaerobic respiration in plant and yeast cells

Word equation

A

Glucose—> ethanol + carbon dioxide

38
Q

Effects of excercise

A

Muscles need energy from respiration to contract, when excercising muscles contract more so more energy is needed. Breathing rate and volume increase to get more oxygen into blood and heart rate increases to get oxygenated blood round the body faster, this removes CO2 more quickly as well

39
Q

Effects of vigourous excercise

A

When doing vigourous excercise the body can’t supply oxygen to the muscles quick enough so they respire anaerobically. This causes lactic acid to build up in the muscles which is painful. Long periods of excercise may also cause muscle fatigue which causes the muscles to stop contracting efficiently

40
Q

Oxygen debt

A

After anaerobic respiration when you stop excercising you’ll have an oxygen debt.
An oxygen debt is the amount of extra oxygen your body needs to react with the build up of lactic acid and remove it from the cells. Oxygen reacts with the lactic acid to form harmless CO2 and water

41
Q

Physical effects of oxygen debt

A

You have to keep breathing hard after you stop excercising to get more oxygen into the blood which is transported to muscle cells. The pulse and breathing rate stay high whilst there are high levels of lactic acid and CO2

42
Q

Alternative way of the body coping with a high level of lactic acid

A

The blood that enters your muscles transports the lactic acid to the liver, in the liver the lactic acid is converted back to glucose

43
Q

To investigate the effects of excercise on the body

A
Take your pulse after:
•sitting down for 5 minutes
•after 5 minutes of gentle walking
•after 5 minutes of slow jogging
•after 5 minutes of running