2hStructures and Functions in Living Organisms
Transport — Edexcel Linear - OL Revision Notes & Topical Questions
5 min read 7 parts Lesson 8 of 25 1 quiz
Lesson summary
Transport Edexcel O Level Linear Biology notes: understand why simple, unicellular organisms can rely on diffusion for movement of substances in and out of the cellLeft ventricle wall is thicker – pumps to whole body.Fetal haemoglobin has higher affinity for O₂ than adult haemogl…
- Transport Edexcel O Level Linear Biology: what to do next
- Double circulation
- Tissue fluid
- Bohr shift
- Cardiac cycle
- Give / State / Name
Section 1 of 7Process & sequence
- SAN
- Atria contract
- AVN (delay)
- Bundle of His
- Purkyne fibres
- Ventricles contract from apex
1
Atrial systole: atria contract, AV valves open.
2
Ventricular systole: AV valves close (lub), blood forced into arteries.
3
Semilunar valves open.
4
Diastole: ventricles relax, semilunar valves close (dub).
5
Heart fills with blood.
Section 2 of 7Keep going
Transport Edexcel O Level Linear Biology: what to do next
These Transport Edexcel O Level Linear Biology notes covered the key ideas, worked examples and exam technique for this topic. Check your Transport Edexcel O Level Linear Biology understanding with the practice questions below, then reread any Transport Edexcel O Level Linear Biology point you were unsure about before moving on.
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Previous lesson: 2g Gas exchange — Notes
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Next lesson: 2i Excretion — Notes
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Course: Edexcel Linear - OL — all units
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Official syllabus: Pearson Edexcel International GCSEs
Section 3 of 7Compare
| Vessel | Wall | Lumen | Pressure | Valves | Function |
|---|---|---|---|---|---|
| Artery | Thick; elastic + smooth muscle | Narrow | High, pulsatile | No (except semilunar at base) | Carry blood from heart |
| Arteriole | Muscular | Small | Falling | No | Control flow to capillaries |
| Capillary | Endothelium only | ~7 µm | Low | No | Exchange of substances |
| Venule | Thin | Small | Low | Some | Collect from capillaries |
| Vein | Thin, little muscle | Wide | Very low | Yes | Return blood to heart |
Section 4 of 7Key terms
Section 5 of 7Syllabus checklist
1
understand why simple, unicellular organisms can rely on diffusion for movement of substances in and out of the cell
2
understand the need for a transport system in multicellular organisms
3
describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant
4
describe the role of xylem in transporting water and mineral ions from the roots to other parts of the plant
5
describe the composition of the blood
- red blood cells
- white blood cells
- platelets and plasma
6
understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones and heat energy
7
understand how adaptations of red blood cells make them suitable for the transport of oxygen,
- including shape, the absence of a nucleus and the presence of haemoglobin understand how the immune system responds to disease using white blood cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen
8
describe the structure of the heart and how it functions
9
explain how the heart rate changes during exercise and under the influence of adrenaline
10
understand how factors may increase the risk of developing coronary heart disease
11
understand how the structure of arteries, veins and capillaries relate to their function
12
understand the general structure of the circulation system, including the blood vessels to and from the heart and lungs, liver and kidneys
Section 6 of 7Command terms
Command terms
Give / State / Name
Recall a fact; one idea per mark.
Define
Give the exact meaning using the specification keywords.
Describe
Give an account of what happens / the pattern in data, quoting values; no reasons needed.
Explain
Give reasons with linked statements (cause → effect). Each linked step is usually a separate marking point.
Suggest
Use knowledge in a new context; more than one answer may be accepted.
Compare
Similarities and differences; each point must refer to both items.
Calculate
Show working; include units; check significant figures. Method marks are given even if the final answer is wrong.
Discuss
Explore the issue from different angles and link the points.
Evaluate / Assess
Weigh strengths and weaknesses and reach a supported judgement.
Deduce
Draw a conclusion from the information given.
Justify
Support a statement/choice with evidence.
Section 7 of 7Exam technique
Keywords the mark scheme looks for in this lesson
Keywords the mark scheme looks for in this lesson
Double circulation · Artery · Vein · Capillary · Tissue fluid · Haemoglobin · Bohr shift · Cardiac cycle
Learn each definition in the Key words tab exactly; a missing keyword in a definition usually loses the mark.
How to get full marks (examiner guidance)
How to get full marks (examiner guidance)
Use specification keywords exactly (e.g. eukaryotic/prokaryotic, enzyme–substrate complex, active site, complementary).
Link ideas
Link ideas for “explain” each marking point is usually a cause → consequence step; unlinked facts often score nothing.
Use the information in the question
“discuss/evaluate” answers must use the data provided and match the number of marks.
Convert units carefully (mg → g, cm³ → dm³) and show working for calculations.
Avoid vague words
“it”, “stuff”, “things”, “goes up”, “energy is made”. Name the substance and the process.
Do not extrapolate a graph line beyond the data or to zero unless asked.
Six-mark extended responses are marked on content AND a logical, linked line of reasoning.
Marked practiceQuizzes for this lesson
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