Topic 8 - Exchange and Transport in animals Flashcards
Why do we need energy? (6)
- To drive the chemical reactions needed to keep us alive.
- Movement - in animals, energy is needed to make muscles contract, while in plants, it is needed for phloem transport.
- For cell division.
- To maintain constant conditions in cells and the body - homeostasis.
- To move molecules against concentration gradients in active transport.
- For the transmission of nerve impulses.
How does the structure of capillaries relate to its function?
Capillaries exchange materials at the tissues. They branch from arteries. They are very narrow so they can carry blood close to every cell in the body to exchange substances with them. They have permeable walls, so substances can diffuse in and out. One cell thick walls to allow a quicker rate of diffusion. They supply oxygen and food and take away waste like carbon dioxide.
How does the structure of plasma relate to its function?
This a pale coloured liquid which carries most things in the blood. Such as:
- Red blood cells, white blood cells and platelets
- Nutrients lie glucose and amino acids
- Carbon dioxide from the organs to the lungs
- Urea from the liver to the kidney
- Hormones
- Proteins
- Antibodies and antitoxins
Describe what Fick’s law tells us about rate of diffusion
It states that the rate of diffusion will double when the surface area or the difference in concentration double or when the thickness halves.
Rate of diffusion = (surface area x concentration difference) ÷ thickness of membrane
Why do we need exchange surfaces and transport systems?
The surface area of a multicellular organism, such as a plant or animal, is small compared to its volume. As a result, multicellular organisms need specialised exchange surfaces (such as lungs or gills) and transport systems.
Describe the need for mineral ions to be transported around the body.
Maintaining the correct balance of mineral ions is essential for cells to function efficiently and effectively. If the water and ion content of the body changes, it can cause too much water to move into or out of its cells - possibly leading to them becoming damaged.
Explain where the 4 main valves in the heart are and what they do? (3)
Valves prevent back flow of blood. Main valves:
Tricuspid valve - Between the right atrium and the right ventricle.
Bicuspid valve - Between the heart’s left atrium and left ventricle.
Semi-lunar valves - There are two: Pulmonary valve - situated between the pulmonary artery and right ventricle: Aortic valve - situated between the aorta and left ventricle.
Describe anaerobic respiration in animals and humans.
When you do really vigorous exercise your body can’t supply enough oxygen to your muscles for aerobic respiration even though your heart rate and breathing rate increase as much as they can. Your muscles have to start respiring anaerobically as well. Anaerobic just means “without oxygen”. It transfers much less energy than aerobic respiration so it’s much less efficient. In anaerobic respiration, the glucose is only partially broken down, and lactic acid is also produced. The lactic acid builds up in the muscles - it gets painful and leads to cramp.
What is the word equation for anaerobic respiration in animals?
Glucose —> Lactic acid
Describe our circulatory system.
We have a double circulatory system which means that the heart pumps blood around the body in two circuits. In the first circuit, the heart pumps deoxygenated blood to the lungs to take in oxygen. Then the oxygenated blood returns to the heart. In the second circuit, the heart pumps oxygenated blood around all the other organs in the body to deliver oxygen to the body cells. Deoxygenated blood returns to the heart.
Describe the need for water to be transported around the body.
If the amount of water is wrong, cells can be damaged because too muh water enters or leaves them. Therefore it needs to be transported out of the body at a controlled rate.
Describe the process of blood being pumped around the body. (4)
1) The right atrium of the heart receives deoxygenated blood from the body (through the vena cava)
2) The deoxygenated blood moves through to the right ventricle, which pumps it to the lungs (via the pulmonary artery).
3) The left atrium receives oxygenated blood from the lungs (through the pulmonary vein).
4) The oxygenated blood then moves through to the left ventricle, which pumps it out round the whole body (via the aorta)
Describe a practical that investigates of respiration in organisms. (6)
1) Set up water bath (5 degrees Celsius - 30 degrees Celsius)
2) Place boiling tube into the water bath for 3 mins so that maggots can get used to the temperature.
3) Connect bung to boiling tube
4) The teacher will add the dye
5) Measure how far the dye has moved in 2 mins. Repeat 3x
6) Reset equipment and repeat with a different temperature.
Describe factors affecting rate of diffusion. (3)
- Diffusion distance as substances diffuse more quickly when they haven’t got far to move.
- Surface area as the more surface area there is available for molecules to move across, the faster they can get from one side to the other.
- Concentration gradient as substances diffuse faster if there’s a big difference in concentration between the area they are diffusing from and the area that they are diffusing to. If there are lots more particles on one side, there are more there to move across.
What is cellular respiration?
An exothermic reaction which occurs continuously in living cells to release energy for metabolic processes including aerobic and anaerobic respiration.
