A Q A Combined Biology Revision

Chapter 1

A Q A Combined Science. Biology revision. This recording covers topics one to seven. Higher tier only content is marked Higher. Pause the recording after each topic and try to repeat three key facts from memory.

Topic one. Cell Biology.

Cell structure.

Eukaryotic cells, like animal and plant cells, have a nucleus containing their genetic material.

Prokaryotic cells, like bacteria, are much smaller. They have no nucleus. Their D N A is a single loop, and they may have small rings of D N A called plasmids.

Animal cells have a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes. Plant cells also have a cellulose cell wall, chloroplasts, and a permanent vacuole filled with cell sap.

Mitochondria are where aerobic respiration happens. Ribosomes are where proteins are made. Chloroplasts are where photosynthesis happens.

Specialised cells.

Microscopy .

Required practical. Preparing a slide, staining it, and viewing cells under a light microscope.

Stem cells.

Topic two. Organisation.

Digestion and enzymes.

The heart and lungs.

Blood.

Heart disease.

Health and disease.

Plant tissues and transport.

Topic Three. Infection and Response.

Viral diseases.

Bacterial diseases.

Fungal and protist diseases.

Human defense systems.

Vaccination and drugs.

Topic Four. Bioenergetics.

Respiration.

Metabolism is the sum of all the reactions in a cell or body.

Topic Five. Homeostasis and Response.

The nervous system.

Required practical. Investigating reaction time, for example using the ruler drop test before and after caffeine.

Blood glucose control.

Contraception.

Topic Six. Inheritance, Variation and Evolution.

D N A and the genome.

Genetic inheritance.

Variation and evolution.

Evidence for evolution.

Classification.

Topic Seven. Ecology.

A stable community is one where species and environmental factors are in balance. Abiotic and biotic factors.