2.69 The urinary System

1. The urethra soon leads to the penis or vagina after being stored in the bladder

2.68b Osmoregulation

1. Need to make sure that the water around the outside of the cell does not become too concentrated or not concentrated enough

2. it needs to be kept isotonic

3. The cell would not be stable if its hypertonic or hypotonic because the water would go into or out of the cell.

4. This is achieved by controlling the concentration of the blood.

5. The kidneys must control the composition

- Keeping an equal salt and water ratio

- this is done through osmoregulation

2.68a Excretion through the kidney --> Urea

1. Urea contains nitrogen

2. Amino Acids move through the liver

3. Taken out as Urea

4. Go into the kidneys and then is filtered and the blood is taken out. (put back into the body)

5. Urea then goes into the bladder

2.67b Humans organs of excretion

1. Lungs excrete CO2

2. Kidneys excrete water, salts and Urea (form of amino acids)

3. skin excretes water salts and sometimes urea - through sweating

2.67 Excretion in plants

1. Plants excrete through photosynthesis and Respiration, depending on what they do.

2. CO2 + H2O --> C6H12O6 + O2

3. This shows that the oxygen is the waste, and it is therefore excreted.

4. C6H12O6 + O2 --> ATP + H20 + CO2

5. Showing that plants excrete CO2 as a waste product of excretion

3.34 Causes of Mutation

3.33 Antibiotic Resistance

3.32 Types of Mutation

3.31 Evolution

3.30 Mutation

3.29 species variation

3.21b Genetic Probabilities

3.21a Genetic probabilities

3.20b Pedigree 2

2.20a Pedigree Diagrams

3.18c Codominance