7.2Unit 1: Cells and organisms
Animal cells — Cambridge Checkpoint Biology 0893 Revision Notes & Topical Questions
5 min read 8 parts Lesson 2 of 4 1 quiz
Lesson summary
7.2 Animal cells — CHECKPOINT BIOLOGY 0893 notes: Identify and state the functions of the structures in an animal cell, compare them with a plant cell, and describe how to view animal cells.Nucleus — contains genetic material (DNA in chromosomes) and controls the activities of th…
- Cell membrane
- Mitochondria
- Nucleus — contains genetic material (DNA in chromosomes) and controls the activities of the cell
- Cytoplasm — a jelly-like substance in which most chemical reactions of the cell take place
- Animal cells do not have a cell wall, chloroplasts or a large permanent vacuole
- They may have small temporary vacuoles
Section 1 of 8Structures in an animal cell
Structures in an animal cell
Nucleus
- Nucleus contains genetic material and controls the activities of the cell.
- (DNA in chromosomes)
Cytoplasm
- Cytoplasm a jelly-like substance in which most chemical reactions of the cell take place.
Cell membrane
- Cell membrane a thin layer around the cell that controls which substances enter and leave.
Mitochondria
- Mitochondria the site of aerobic respiration, which releases energy from glucose for the cell.
Section 2 of 8Structures animal cells lack
Structures animal cells lack
Animal cells do not have a cell wall, chloroplasts or a large permanent vacuole.
They may have small temporary vacuoles.
They have no fixed shape because they have no cell wall.
Section 3 of 8Comparing animal and plant cells
| Structure | Animal cell | Plant cell | Function |
|---|---|---|---|
| Nucleus | Yes | Yes | Controls the cell |
| Cytoplasm | Yes | Yes | Site of chemical reactions |
| Cell membrane | Yes | Yes | Controls what enters and leaves |
| Mitochondria | Yes | Yes | Release energy by aerobic respiration |
| Cell wall | No | Yes, made of cellulose | Supports the cell |
| Chloroplasts | No | In green parts | Photosynthesis |
| Large sap vacuole | No | Yes | Keeps the cell firm |
Section 4 of 8Identifying the type of cell
1
Look for a cell wall, which appears as a clear straight outline.
2
Look for green chloroplasts.
3
Look for one large clear vacuole.
4
A cell with none of these three is an animal cell, and a cell with them is a plant cell.
Section 5 of 8Specialised animal cells
Specialised animal cells
Many animal cells are specialised, with features suited to their function.
Examples are red blood cells, nerve cells and sperm cells.
Section 6 of 8Viewing cheek cells
- Stains make the nucleus and other structures easier to see, because cell parts are mostly colourless.
- Method:
1
Gently rub the inside of the cheek with a clean cotton bud.
2
Smear the cotton bud onto the centre of a clean glass slide.
3
Add one drop of methylene blue stain.
4
Lower a cover slip at an angle to avoid trapping air bubbles.
5
Observe using the lowest-power objective lens first, then increase magnification and focus with the fine focus.
6
Draw and label one or two cells.
Section 7 of 8Key terms
| Term | Meaning |
|---|---|
| Nucleus | The structure that contains genetic material and controls the cell's activities. |
| Cytoplasm | The jelly where most of the cell's chemical reactions happen. |
| Cell membrane | A thin layer that controls what enters and leaves the cell. |
| Mitochondria | Structures where aerobic respiration releases energy from food. |
| Stain | A dye that makes cell structures easier to see. |
| Cell wall | A strong cellulose layer outside the membrane of a plant cell. |
Section 8 of 8Exam technique
1
Saying the membrane protects the cell — it controls what enters and leaves.
2
Saying mitochondria make energy — they release energy from glucose by aerobic respiration.
3
Saying animal cells have a cell wall — animal cells have only a cell membrane.
4
Saying the cytoplasm is just water — it is the jelly where most chemical reactions take place.
5
Saying only plant cells have mitochondria — animal cells have them too.
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Cambridge 9700 AS Biology
Core Formula
Magnification Triangle & Unit Conversion
Formula: M = I / A ⇔ A = I / M ⇔ I = M × A
Units: 1 mm = 1,000 μm = 1,000,000 nm.
Rule: Convert Image size (ruler mm) to μm by ×1,000 before dividing by Actual size.