AQA GCSE Biology (Higher Tier) — Complete
Topic Summary
Topic 1: Cell Biology
Cell Structure
Eukaryotic cells contain:
o Nucleus
o Cytoplasm
o Cell membrane
o Mitochondria
o Ribosomes
Plant cells also contain:
o Cell wall
o Permanent vacuole
o Chloroplasts
Prokaryotic cells:
o Smaller and simpler
o No nucleus
o DNA loop and plasmids
Microscopy
Light microscopes:
o Lower magnification and resolution
o Can observe living cells
Electron microscopes:
o Higher magnification and resolution
o More detailed images
Magnification formula:
o Magnification = image size ÷ actual size
Cell Division
Mitosis
Produces two genetically identical cells
Used for:
o Growth
o Repair
, o Asexual reproduction
Stem Cells
Unspecialised cells
Can differentiate into specialised cells
Sources:
o Embryonic stem cells
o Adult stem cells
o Meristem cells in plants
Transport in Cells
Diffusion
Movement from high to low concentration
Osmosis
Movement of water through a partially permeable membrane
Active Transport
Movement against concentration gradient
Requires energy
Topic 2: Organisation
Organisation Levels
Cells → tissues → organs → organ systems → organism
Digestive System
Functions of:
o Stomach
o Liver
o Pancreas
o Small intestine
Enzymes:
o Amylase
o Protease
o Lipase
Enzymes Required Practical
Effect of pH on amylase activity
Topic Summary
Topic 1: Cell Biology
Cell Structure
Eukaryotic cells contain:
o Nucleus
o Cytoplasm
o Cell membrane
o Mitochondria
o Ribosomes
Plant cells also contain:
o Cell wall
o Permanent vacuole
o Chloroplasts
Prokaryotic cells:
o Smaller and simpler
o No nucleus
o DNA loop and plasmids
Microscopy
Light microscopes:
o Lower magnification and resolution
o Can observe living cells
Electron microscopes:
o Higher magnification and resolution
o More detailed images
Magnification formula:
o Magnification = image size ÷ actual size
Cell Division
Mitosis
Produces two genetically identical cells
Used for:
o Growth
o Repair
, o Asexual reproduction
Stem Cells
Unspecialised cells
Can differentiate into specialised cells
Sources:
o Embryonic stem cells
o Adult stem cells
o Meristem cells in plants
Transport in Cells
Diffusion
Movement from high to low concentration
Osmosis
Movement of water through a partially permeable membrane
Active Transport
Movement against concentration gradient
Requires energy
Topic 2: Organisation
Organisation Levels
Cells → tissues → organs → organ systems → organism
Digestive System
Functions of:
o Stomach
o Liver
o Pancreas
o Small intestine
Enzymes:
o Amylase
o Protease
o Lipase
Enzymes Required Practical
Effect of pH on amylase activity
