1. Biology Unit 2 – Topic 2
Organisms and energy

2. Respiration
Respiration is a process used by all living organisms that releases the energy in organic molecules

3. Glucose and oxygen diffuses from capillaries into respiring cells.
Respiration
Glucose and oxygen diffuses from capillaries into respiring cells.

4. Carbon dioxide diffuses from respiring cells into capillaries.
Respiration
Carbon dioxide diffuses from respiring cells into capillaries.

5. Diffusion
Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration.

6. Aerobic respiration uses Oxygen to release energy from glucose.

7. Aerobic respiration Glucose + oxygen carbon dioxide +water
The energy from the glucose is released for use in the cell.

8. Exercise can cause a change in heart and breathing rates.

9. Exercise
During exercise the muscles use up oxygen and glucose quickly, so the breathing rate increases to get more oxygen and the heart beats faster to pump more blood with more oxygen and glucose to these cells.

10. Amount of blood
The cardiac output is the volume of blood circulated by the heart in a given time.

11. Cardiac output = stroke volume x heart rate
Amount of blood
Cardiac output = stroke volume x heart rate

12. Amount of blood
Cardiac output
Stroke volume
Heart rate

13. Anaerobic respiration
Sometimes, when we carry out vigorous exercise we cannot supply enough oxygen to the muscle cells so we start to respire anaerobically.

14. Anaerobic respiration
Anaerobic respiration breaks down glucose and releases energy without any oxygen.

15. Anaerobic Respiration
Glucose lactic acid
The energy from the glucose is released for use in the cell.

16. Anaerobic Respiration
releases less energy
than aerobic respiration.

17. Lactic acid
Lactic acid produced by anaerobic respiration exercise may cause muscle cramps.

18. Excess post-exercise oxygen consumption.
Lactic acid
After exercise increased oxygen is required to break down the Lactic acid into carbon dioxide and water. This need for extra oxygen after exercise is called
Excess post-exercise oxygen consumption.
(EPOC)

19. Photosynthesis A leaf is adapted for photosynthesis.
Large surface area
Chlorophyll in chloroplasts to absorb light
Stomata for gas exchange
(carbon dioxide, oxygen and water)

20. Photosynthesis Plants absorb light energy to make glucose.
Carbon dioxide + water glucose + oxygen

21. Rate of photosynthesis
For photosynthesis to happen there must be enough carbon dioxide, water, a suitable temperature and light to give the energy for the reactions. The one that is in the shortest supply is called the limiting factor.

22. Water transport
Roots do more than just anchor a plant to the ground. They take up water and dissolved nitrate and other mineral ions from the soil.

23. for the water and mineral ions to enter.
Root hair cells
Root hair cells have long tin extensions that reach into the nearby soil. This gives them a
bigger surface area
for the water and mineral ions to enter.

24. Water transport Water enters the root hair cells by osmosis.
Here, water moves across a
partially permeable membrane.

25. Osmosis Osmosis is the movement of water molecules
from an area of higher concentration of water
to an area of lower concentration of water
through a partially permeable membrane.

26. This is the evaporation of water vapour from the surface of a plant.
Transpiration
This is the evaporation of water vapour from the surface of a plant.

27. This process is called transpiration.
The loss of water from a leaf pulls water and dissolved mineral salts up through the xylem from the roots.
This process is called transpiration.

28. Active transport
Roots can absorb nitrates and other mineral ions dissolved in soil water even if the concentration is higher in the plant than in the soil water. Absorbing particles against a concentration gradient is called active transport. The energy for this comes from repiration.

29. Xylem vessels transport water and dissolved mineral salts up a plant.
Water Xylem
W X

30. Phloem vessels
The glucose made in the leaves by photosynthesis is converted to sucrose and carried to other parts of the plant by the phloem tissue.

31. A pooter is used to suck small invertebrates into a tube.
Sampling techniques
A pooter is used to suck small invertebrates into a tube.

32. Sampling techniques
A sweep net is used to drag through long grass to catch any organisms. Similarly, a pond net could be used for aquatic habitats.

33. A pitfall trap is a jar which small animals fall into and are trapped.
Sampling techniques
A pitfall trap is a jar which small animals fall into and are trapped.

34. Sampling techniques
A quadrat is a square frame placed at random place on the ground and the plants in that area counted.

35. Environmental factors which could be measured include:
Sampling techniques
Environmental factors which could be measured include:
Temperature
Light intensity pH