Biology Exam Preparation Lecture

Introduction

• Casual hour planned for genetics discussion.
• Sudden need for PowerPoint due to various topic requests.
• Topics pulled from different group chats, aiming to cover as much as possible.
• Focus is on set topics for the biology exam.

Sections Overview

Section A

• No questions were requested, but advised to review as it still carries significant marks.

Section B

Nutrition

• Photosynthesis:
  • Defined as the process by which plants use carbon dioxide and water to produce glucose and oxygen.
  • Requires light and chlorophyll.
  • Chemical equation must be balanced.
  • Familiarity with experiments proving necessity of light and chlorophyll is important.
• Leaf Structure:
  • Adapted for photosynthesis with features like large surface area and thin structure.
  • Important structures include upper epidermal cell, palisade mesothelium, vascular bundle (xylem), and spongy mesophyll cell.
• Food Tests:
  • Tests for reducing sugars, protein, lipid, and carbohydrate.
  • Reagents: Benedict's for sugars, Biuret for proteins, Emulsion test for fats, Iodine for starch.
  • Detailed color changes for positive and negative results.

Digestive System

• Organ Identification: Liver, stomach, pancreas, large intestine, small intestine.
• Digestion Process:
  • Begins in the mouth with mechanical and chemical digestion.
  • Salivary amylase begins starch digestion.
  • Mechanical digestion continues through the alimentary canal via muscle contraction.
  • Bile emulsifies fats; pancreatic juice contributes to digestion in the small intestine.
• Enzyme Action:
  • Descriptions of how different enzymes break down carbohydrates, proteins, and lipids.

Respiratory System

• Labeling Parts: Nasal cavity, pharynx, trachea, bronchi, lungs, diaphragm.
• Breathing vs. Respiration:
  • Breathing involves air movement; respiration involves energy release from glucose.
• Gas Exchange:
  • Process of oxygen entering blood via alveoli.
  • Differences in plant and human oxygen acquisition.

Aerobic vs. Anaerobic Respiration

• Aerobic Respiration:
  • Requires oxygen, produces ATP, carbon dioxide, and water.
• Anaerobic Respiration:
  • Occurs when oxygen is scarce, produces lactic acid and less ATP.
  • Lactic acid buildup causes muscle fatigue and requires oxygen for breakdown.

Circulatory System

• Heart Anatomy: Left atrium and ventricle, right atrium and ventricle.
• Blood Flow Pathway:
  • Deoxygenated blood brought to the heart, oxygenated blood sent to the body.
• Heart Operation:
  • Atria contract together, ventricles contract together.
  • Ventricular contraction results in a heartbeat/pulse.

Conclusion

• Biology session to be paused for chemistry; will resume later with further topics like mitosis, meiosis, and inheritance.