GCSE Biology Higher Tier Paper 1H Summary

Coronary Heart Disease (CHD): Primary affects the arteries; treated with stents to keep arteries open or drugs like statins to lower blood cholesterol levels.
Emergency Response: Pushing on the chest (CPR) puts pressure on the heart to manually pump blood around the body. Forcing air into the lungs provides oxygen for the blood to transport.
Risk Factors: Data indicates increased risk in categories E ( $14\%$ ), F ( $20\%$ ), G ( $29\%$ ), and H ( $70\%$ ) for smokers. Other lifestyle factors include high-fat diets and lack of exercise.

Genetics: CF is an inherited disorder caused by a faulty gene found in the nucleus of a cell.
Digestive Impact: A reduction in digestive enzymes reaching the small intestine results in incomplete digestion of food and difficulty gaining body mass due to lack of nutrient absorption.
Respiratory Impact: Alveoli maximize gas exchange through thin walls, large surface area, and a rich blood supply. Reduced oxygen entry into the blood leads to less aerobic respiration, resulting in less energy release for the body.

Chemical Tests for Carbohydrates:
- Starch: Iodine solution.
- Sugars: Benedict's solution (requires heating in a water bath).
Digestive Action: Bread eventually tastes sweet in the mouth because amylase enzymes in saliva break down starch into simple sugars.

Leaf Structure:
- Palisade Mesophyll: Contains the most chloroplasts for photosynthesis.
- Spongy Mesophyll: Contains air spaces for gas exchange.
- Meristem: Tissue that differentiates throughout the life of the plant.
Transport Systems:
- Xylem: Transports water; walls are strengthened by cellulose and lignin.
- Phloem: Transports dissolved sugars via translocation; requires mitochondria in specialized cells to provide energy for active transport.

Osmosis in Potatoes: In solutions like $0.6\,mol/dm^3$ or $1.0\,mol/dm^3$ , potato pieces lose mass as water moves out of the cells from a higher water potential to a lower water potential (more concentrated salt solution).
Pathogens: Antibiotics like Penicillin treat bacterial infections but are ineffective against viruses. Viruses cannot be grown on agar because they require a live host cell to replicate.
Viral Disease: AIDS is caused by a virus that damages white blood cells.

Factors: Photosynthesis requires light, $CO_2$ , and chlorophyll. Deficiency in Magnesium ions causes yellow leaves (chlorosis).
Rate Measurement: Can be measured by the volume of oxygen produced.
Inverse Square Law: The relationship between light intensity and distance is expressed as: $\text{light intensity} \propto \frac{1}{\text{distance}^2}$

Preparation for Division: Cells replicate DNA to form two copies of each chromosome and increase the number of sub-cellular structures (e.g., mitochondria).
Cancer Treatment: Drugs like Drug X stop cell division by preventing spindle fibres from attaching to chromosomes, halting the uncontrolled division of cancerous cells.
Drug Development: Preclinical testing involves testing drugs on live tissues or chemicals in a laboratory before human clinical trials.