Master GCSE Biology

MS1:

- A group of similar cells that perform a specific function (1)

- Example: muscle tissue (1)

MS2:

- Epithelial (e.g., lining of the stomach)

- Connective (e.g., blood)

- Muscle (e.g., skeletal muscle)

- Nervous (e.g., brain cells) (2)

MS3:

- Increase the rate of reactions by lowering the activation energy (1)

- Have an active site that binds to specific substrates (1)

MS4:

- Bile is produced by the liver and stored in the gallbladder (1)

- Emulsification: Bile breaks down fats into smaller droplets (1)

- This increases the surface area of the fats, making them easier to digest by enzymes (1)

MS5:

- Arteries: Carry blood away from the heart, have thick elastic walls, and high blood pressure (1)

- Veins: Carry blood back to the heart, have thinner walls, and lower blood pressure (1)

- Capillaries: Smallest blood vessels, exchange of gases and materials occurs here (1)

MS6:

- Structure: Flap of tissue that allows blood to flow in only one direction (1)

- Prevents backflow of blood, ensuring efficient blood circulation (1)

- Malfunction: Can cause blood to leak back, leading to problems such as heart murmurs or valve replacement surgery (1)

MS7:

- Red blood cells: Carry oxygen around the body (1)

- White blood cells: Protect against infection and disease (1)

- Platelets: Help with blood clotting and stop bleeding (1)

MS8:

- Xylem:

- Dead, hollow vessels with no end walls

- Tracheids have thickened, lignified walls, allowing water to pass easily (1)

- Phloem:

- Living cells with perforated end walls

- Sieve tubes have no nuclei, increasing the flow of sugars (1)

MS9:

- When turgid, guard cells open the stomata to allow water vapor out (1)

- When flaccid, guard cells close the stomata to conserve water (1)

MS10:

- Causes: High cholesterol, obesity, smoking (1)

- Consequences: Narrowed arteries, increased blood pressure, risk of heart attack or stroke (1)

- Treatment: Statins, stents to widen arteries (1)

- Prevention: Healthy diet, exercise, avoiding smoking, managing cholesterol levels (1)