AQA GCSE Biology · Topic 1
Eukaryotic and prokaryotic cells, animal and plant cell structure, specialisation, differentiation and microscopy.
156 questions 5 subtopics Spec 4.1
Every subtopic below has its own questions, mark schemes and notes once you start.
Every living thing is built from cells, and every cell is one of two kinds. The dividing line is simple: is the DNA shut inside a nucleus, or not?
Plant cells contain everything an animal cell has, plus three extras. Learn the animal list first, then add the three.
A specialised cell has a shape and a set of structures that suit one particular job. Six examples are needed: three animal, three plant.
Differentiation is a cell becoming specialised. It is not the same as cell division, which is a cell making more cells.
Microscopes have improved as technology has, letting us see more detail. Two ideas run through this topic: magnification and resolution are different things, and units must always match before you calculate.
Key definitions, in exam-ready wording.
The mistakes that come up again and again in this topic.
'Bacteria have no DNA' is wrong and costs marks. They have DNA, it just isn't in a nucleus.
Ribosomes are never a valid difference between prokaryotes and eukaryotes: both have them.
Bacteria do have a cell wall. The structures they lack are the nucleus, mitochondria and chloroplasts.
Chloroplast is the structure; chlorophyll is the pigment inside it. Mixing the words up loses the mark.
The word 'permanent' matters, animal cells can have small temporary vacuoles.
The nucleus controls the cell through its genetic material; the enzymes in the cytoplasm control the chemical reactions.
Adaptation questions want the feature AND why it helps. 'It has lots of mitochondria' alone is half an answer.
The tail makes a sperm swim, but the mitochondria supply the energy. Check which the question asks for.
A specialised cell only keeps the structures its job needs, that reasoning works on unfamiliar cells too.
Differentiation = becoming specialised. Division = making more cells. Examiners test that you can tell them apart.
The animal/plant comparison is worth two marks: say what happens in each, not just one.
Check units first, calculate second.
Start on the lowest-powered objective lens. Starting high risks hitting the slide and makes the specimen hard to find.
A light microscope can show mitochondria as blobs, it is their internal structure that needs an electron microscope.
156 questions on Cell biology, marked against the scheme. Anything you get stuck on will be scheduled to come back sooner.