GCSE SCIENCE REVISION NOTES
Edexcel GCSE Biology
Complete revision notes · Foundation tier · Specification 1BI0
All 9 topics, Papers 1 and 2 All 8 core practicals Worked examples
Quick-check questions with answers Contents page and numbered pages
Pastel colour-coded by topic · Written to follow the Pearson Edexcel GCSE (9-1) Biology specification
Independent notes, not produced or endorsed by Pearson or Edexcel
,Contents
1 Key concepts in biology 3
2 Cells and control 8
3 Genetics 11
4 Natural selection and genetic modification 14
5 Health, disease and the development of medicines 17
6 Plant structures and their functions 20
7 Animal coordination, control and homeostasis 23
8 Exchange and transport in animals 26
9 Ecosystems and material cycles 29
Core practical reference sheet 32
Exam checklist 33
How to use these notes
Each topic starts with a coloured banner. The same colour is used for that topic throughout, so you can
find it fast.
Key points are the facts the exam expects. Definitions (orange boxes) are worth learning word for
word.
Worked examples (blue boxes) show every step of the calculations.
Core practicals (green boxes) are the 8 required practicals. You will be asked about their methods in the
exam.
Quick checks (purple boxes) end every topic. Cover the answers, try the questions, then mark yourself.
Exam tips (pink boxes) flag the mistakes examiners see most.
Your exam at a glance
Paper 1 (1BI0/1F) Paper 2 (1BI0/2F)
Topics 1, 2, 3, 4, 5 1, 6, 7, 8, 9
Time 1 hour 45 minutes 1 hour 45 minutes
Marks 100 100
Question styles Multiple choice, short answer, calculations and extended open-response questions
Foundation tier targets grades 1 to 5. Some questions are shared with the higher tier paper, so aim to be
secure on every topic, not just the easier ones. Calculators are allowed.
Edexcel GCSE Biology · Foundation · page 2 of 33
, TOPIC 1 · PAPERS 1 AND 2
Key concepts in biology
1.1 Cell structure
All living things are made of cells. Eukaryotic cells (animal and plant cells) have a nucleus containing their
DNA. Prokaryotic cells (bacteria) are much smaller and have no nucleus; their DNA floats free in the
cytoplasm.
Structure Function Animal Plant Bacterium
Nucleus Contains DNA; controls the cell's activities ✓ ✓ ✗ (loop of chromosomal
DNA instead)
Cell membrane Controls what enters and leaves the cell ✓ ✓ ✓
Cytoplasm Jelly-like substance where most chemical ✓ ✓ ✓
reactions happen
Mitochondria Aerobic respiration releases energy here ✓ ✓ ✗
Ribosomes Protein synthesis (making proteins) ✓ ✓ ✓
Cell wall Supports and strengthens the cell (made ✗ ✓ ✓
of cellulose in plants)
Chloroplasts Contain chlorophyll; absorb light for ✗ ✓ ✗
photosynthesis
Permanent Filled with cell sap; keeps the cell firm ✗ ✓ ✗
vacuole (turgid)
Plasmid DNA Small extra rings of DNA carrying ✗ ✗ ✓
additional genes
Flagella Rotate to move the bacterium ✗ ✗ ✓ (some)
1.2 Specialised cells
Sperm cell: has a tail to swim, many mitochondria to release energy for swimming, an acrosome
containing enzymes to digest into the egg, and a haploid nucleus (half the normal number of
chromosomes).
Egg cell: has nutrients in the cytoplasm to feed the early embryo, a haploid nucleus, and its cell
membrane changes after fertilisation to stop any more sperm entering.
Ciliated epithelial cells: line the airways. Tiny hairs called cilia beat to waft mucus (with trapped dust
and microbes) up to the throat to be swallowed.
1.3 Microscopes
Early light microscopes let scientists see cells for the first time, but they cannot show the fine detail of
organelles. Electron microscopes have much higher magnification and resolution, so scientists can now
Edexcel GCSE Biology · Foundation · page 3 of 33
, see structures such as ribosomes and the internal membranes of mitochondria and chloroplasts. This has
hugely increased our understanding of how cells work.
DEFINITIONS
Magnification: how much bigger the image is than the real object. Resolution: the ability to tell two
very close points apart as separate.
1.4 and 1.5 Size, scale and units
Cells are measured using very small units. You must be able to convert between them and use standard
form:
Unit Symbol Size
millimetre mm 10−3 m (1 000 mm = 1 m)
micrometre µm 10−6 m (1 000 µm = 1 mm)
nanometre nm 10−9 m (1 000 nm = 1 µm)
WORKED EXAMPLE · CONVERTING UNITS
A cell is 0.02 mm wide. What is this in micrometres?
1 mm = 1 000 µm, so multiply by 1 000: 0.02 × 1 000 = 20 µm.
CORE PRACTICAL 1 · USING A MICROSCOPE
Aim: observe biological specimens, calculate magnification and produce a labelled scientific drawing.
Method:
1. Place the slide on the stage and select the lowest-power objective lens first.
2. Use the coarse focus to bring the specimen into view, then the fine focus for a sharp image.
3. Move to a higher-power objective lens and refocus with the fine focus only.
4. Draw what you see: sharp, unshaded pencil lines, no colouring, with labels for each structure.
Total magnification = eyepiece lens magnification × objective lens magnification (e.g. ×10 eyepiece
and ×40 objective = ×400).
Image size, actual size and magnification: magnification = image size ÷ actual size
W O R K E D E X A M P L E · M A G N I F I C AT I O N
A drawing of a cell is 45 mm wide. The real cell is 0.09 mm wide. Calculate the magnification.
Magnification = image size ÷ actual size = 45 ÷ 0.09 = ×500.
EXAM TIP
Convert both sizes to the same unit before dividing. Mixing mm and µm is the most common way to
lose these marks.
Edexcel GCSE Biology · Foundation · page 4 of 33
Edexcel GCSE Biology
Complete revision notes · Foundation tier · Specification 1BI0
All 9 topics, Papers 1 and 2 All 8 core practicals Worked examples
Quick-check questions with answers Contents page and numbered pages
Pastel colour-coded by topic · Written to follow the Pearson Edexcel GCSE (9-1) Biology specification
Independent notes, not produced or endorsed by Pearson or Edexcel
,Contents
1 Key concepts in biology 3
2 Cells and control 8
3 Genetics 11
4 Natural selection and genetic modification 14
5 Health, disease and the development of medicines 17
6 Plant structures and their functions 20
7 Animal coordination, control and homeostasis 23
8 Exchange and transport in animals 26
9 Ecosystems and material cycles 29
Core practical reference sheet 32
Exam checklist 33
How to use these notes
Each topic starts with a coloured banner. The same colour is used for that topic throughout, so you can
find it fast.
Key points are the facts the exam expects. Definitions (orange boxes) are worth learning word for
word.
Worked examples (blue boxes) show every step of the calculations.
Core practicals (green boxes) are the 8 required practicals. You will be asked about their methods in the
exam.
Quick checks (purple boxes) end every topic. Cover the answers, try the questions, then mark yourself.
Exam tips (pink boxes) flag the mistakes examiners see most.
Your exam at a glance
Paper 1 (1BI0/1F) Paper 2 (1BI0/2F)
Topics 1, 2, 3, 4, 5 1, 6, 7, 8, 9
Time 1 hour 45 minutes 1 hour 45 minutes
Marks 100 100
Question styles Multiple choice, short answer, calculations and extended open-response questions
Foundation tier targets grades 1 to 5. Some questions are shared with the higher tier paper, so aim to be
secure on every topic, not just the easier ones. Calculators are allowed.
Edexcel GCSE Biology · Foundation · page 2 of 33
, TOPIC 1 · PAPERS 1 AND 2
Key concepts in biology
1.1 Cell structure
All living things are made of cells. Eukaryotic cells (animal and plant cells) have a nucleus containing their
DNA. Prokaryotic cells (bacteria) are much smaller and have no nucleus; their DNA floats free in the
cytoplasm.
Structure Function Animal Plant Bacterium
Nucleus Contains DNA; controls the cell's activities ✓ ✓ ✗ (loop of chromosomal
DNA instead)
Cell membrane Controls what enters and leaves the cell ✓ ✓ ✓
Cytoplasm Jelly-like substance where most chemical ✓ ✓ ✓
reactions happen
Mitochondria Aerobic respiration releases energy here ✓ ✓ ✗
Ribosomes Protein synthesis (making proteins) ✓ ✓ ✓
Cell wall Supports and strengthens the cell (made ✗ ✓ ✓
of cellulose in plants)
Chloroplasts Contain chlorophyll; absorb light for ✗ ✓ ✗
photosynthesis
Permanent Filled with cell sap; keeps the cell firm ✗ ✓ ✗
vacuole (turgid)
Plasmid DNA Small extra rings of DNA carrying ✗ ✗ ✓
additional genes
Flagella Rotate to move the bacterium ✗ ✗ ✓ (some)
1.2 Specialised cells
Sperm cell: has a tail to swim, many mitochondria to release energy for swimming, an acrosome
containing enzymes to digest into the egg, and a haploid nucleus (half the normal number of
chromosomes).
Egg cell: has nutrients in the cytoplasm to feed the early embryo, a haploid nucleus, and its cell
membrane changes after fertilisation to stop any more sperm entering.
Ciliated epithelial cells: line the airways. Tiny hairs called cilia beat to waft mucus (with trapped dust
and microbes) up to the throat to be swallowed.
1.3 Microscopes
Early light microscopes let scientists see cells for the first time, but they cannot show the fine detail of
organelles. Electron microscopes have much higher magnification and resolution, so scientists can now
Edexcel GCSE Biology · Foundation · page 3 of 33
, see structures such as ribosomes and the internal membranes of mitochondria and chloroplasts. This has
hugely increased our understanding of how cells work.
DEFINITIONS
Magnification: how much bigger the image is than the real object. Resolution: the ability to tell two
very close points apart as separate.
1.4 and 1.5 Size, scale and units
Cells are measured using very small units. You must be able to convert between them and use standard
form:
Unit Symbol Size
millimetre mm 10−3 m (1 000 mm = 1 m)
micrometre µm 10−6 m (1 000 µm = 1 mm)
nanometre nm 10−9 m (1 000 nm = 1 µm)
WORKED EXAMPLE · CONVERTING UNITS
A cell is 0.02 mm wide. What is this in micrometres?
1 mm = 1 000 µm, so multiply by 1 000: 0.02 × 1 000 = 20 µm.
CORE PRACTICAL 1 · USING A MICROSCOPE
Aim: observe biological specimens, calculate magnification and produce a labelled scientific drawing.
Method:
1. Place the slide on the stage and select the lowest-power objective lens first.
2. Use the coarse focus to bring the specimen into view, then the fine focus for a sharp image.
3. Move to a higher-power objective lens and refocus with the fine focus only.
4. Draw what you see: sharp, unshaded pencil lines, no colouring, with labels for each structure.
Total magnification = eyepiece lens magnification × objective lens magnification (e.g. ×10 eyepiece
and ×40 objective = ×400).
Image size, actual size and magnification: magnification = image size ÷ actual size
W O R K E D E X A M P L E · M A G N I F I C AT I O N
A drawing of a cell is 45 mm wide. The real cell is 0.09 mm wide. Calculate the magnification.
Magnification = image size ÷ actual size = 45 ÷ 0.09 = ×500.
EXAM TIP
Convert both sizes to the same unit before dividing. Mixing mm and µm is the most common way to
lose these marks.
Edexcel GCSE Biology · Foundation · page 4 of 33
