The shape of the lesson
By the end of the lesson, learners can
- The male and female systems: The lab shows diagrammatic models of both systems.
- Sperm and egg: built for the job: Open the gametes tab.
- From zygote to implantation: Drag the day slider from 0 to 7, or press Play.
- Male: testes, scrotum, sperm ducts, prostate gland, urethra, penis.
- Female: ovaries, oviducts (fertilisation), uterus (implantation), cervix, vagina.
- Sperm: flagellum, mitochondria, acrosome enzymes. Egg: energy stores, jelly coat that changes.
- Compare gametes on size, structure, motility and numbers.
One picture every idea returns to
Fertilisation is the fusion of the nuclei from a male gamete (sperm) and a female gamete (egg cell); in humans it happens in the oviduct. Sperm are small, numerous and swim using a flagellum; egg cells are large, few and cannot move by themselves. In early development the zygote forms an embryo, which is a ball of cells that implants into the lining of the uterus.
Forty-five minutes, phase by phase
| Time | Phase | What happens in the room | Grouping |
|---|---|---|---|
| 0 to 5 min | Hook: predict | Open with the question in the title, Gametes, fertilisation, implantation.. The male reproductive system makes millions of sperm and delivers them; the female system releases an egg cell, provides a place for fertilisation and then shelters the developing embryo. Put the figure on the board: it is the one picture every idea in the lesson returns to. | Whole class, then pairs |
| 5 to 13 min | Teach and check: The male and female systems | The lab shows diagrammatic models of both systems. Project tab 1 of the lab (The reproductive systems) and let a student drive it while the class predicts. | Whole class, then pairs |
| 13 to 21 min | Teach and check: Sperm and egg: built for the job | Open the gametes tab. Project tab 2 of the lab (Gametes and fertilisation) and let a student drive it while the class predicts. | Pairs |
| 21 to 30 min | Teach and check: From zygote to implantation | Drag the day slider from 0 to 7, or press Play. Project tab 3 of the lab (From zygote to implantation) and let a student drive it while the class predicts. | Frayer Model |
| 30 to 36 min | Check | The four Stage 1 questions from the student lesson, answered on mini whiteboards or by show of fingers. Re-teach the one most get wrong. | Individual, then whole class |
| 36 to 43 min | Plenary | The exam-style questions from Stage 2, one at a time: thirty seconds alone, then a random call. The feedback lines in the key give the examiner's wording. | Individual, random call |
| 43 to 45 min | Exit and homework | Set the worksheet below (6 questions, 17 marks). Learners self-assess against the objectives before they leave. | Individual |
Protect the parts that carry the learning
The sequence carries about fifty minutes of material, so the lab is driven by one student while the class predicts rather than explored freely. Times are a guide.
Protected: the check at 30 minutes. It is the only individual read on whether the key idea landed, and it is not cut.
Cut first if the build overruns: the last check in From zygote to implantation, never the check or the plenary.
In a 60 minute block: run worksheet questions 1 to 3 in class as a Rally Coach set and model both the hardest worked example and its check live.
Frayer Model
Pairs fill a four-box grid for the key term: definition, characteristics, examples and non-examples. The non-examples box is where the misconceptions surface, so give it the most time.
The full structure, with its variations and the other twelve, is on the cooperative-learning page.
What to head off, and how
| Trap learners fall into | Teaching move that pre-empts it |
|---|---|
| The sperm duct carries sperm; the urethra carries semen and urine out of the body. | The oviduct (not the uterus) is where fertilisation normally happens. The bladder in the model is not part of the reproductive system. |
| Mitochondria give the sperm energy for swimming; they do not make it swim. | The flagellum is what moves. Say "release energy by respiration", never "produce energy". |
| The embryo does not implant in the oviduct or the ovary. | It implants in the lining of the uterus. |
Human reproductive systems and gametes: worksheet
6 questions, 17 marks. Written in the style of the papers; no past paper question is reproduced.
State the function of (a) the testes, (b) the scrotum, (c) the oviduct and (d) the cervix.
Describe fertilisation in humans.
Explain how three features of a sperm cell adapt it for its function.
Compare a human sperm with a human egg cell in terms of size, structure, motility and numbers.
Explain the importance of the energy stores in the cytoplasm of an egg cell.
Describe what happens to a zygote between fertilisation and implantation.
Answer key and marking notes
- (a) Testes: produce sperm (and testosterone).
- (b) Scrotum: holds the testes outside the body, at a slightly lower temperature, better for sperm production.
- (c) Oviduct: carries the egg from the ovary to the uterus; site of fertilisation.
- (d) Cervix: ring of muscle at the base of the uterus; widens during birth.
The nucleus of a sperm (male gamete) fuses with the nucleus of an egg cell (female gamete).
- Flagellum: beats so the sperm can swim to the egg.
- Many mitochondria: release energy by respiration for swimming.
- Acrosome containing enzymes: digests a way through the jelly coat into the egg.
- Size: the sperm is much smaller (head about 5 μm) than the egg (about 0.1 mm).
- Structure: the sperm has a head with an acrosome, a midpiece with mitochondria and a flagellum; the egg has a large cytoplasm with energy stores and a jelly coat.
- Motility: the sperm swims; the egg cannot move by itself.
- Numbers: millions of sperm are released; usually one egg is released a month.
- After fertilisation the zygote divides many times on its way to the uterus.
- It cannot yet get nutrients from the mother, so the stored food supplies the energy and materials for these divisions until implantation.
- The zygote divides repeatedly by mitosis to form a ball of cells, the embryo.
- It is moved along the oviduct to the uterus.
- It implants into the thick lining of the uterus (about a week after fertilisation).
8 multiple-choice questions on this lesson
From the topic question bank. Assign them in the app for a marked score in your gradebook, or run the topic as a class game.
The diagram shows part of the male reproductive system. Which letter labels the structure that adds fluid to sperm to make semen?
- AR
- BP
- CQ
- DS
Which structure carries both semen and urine, at different times, out of the body?
- Aurethra
- Bsperm duct
- Coviduct
- Dbladder
In which part of the female reproductive system does fertilisation normally take place?
- Aoviduct
- Buterus
- Covary
- Dvagina
Why are the testes held outside the body in the scrotum?
- ASperm are produced best slightly below body temperature
- BSo they are protected from physical damage
- CSo sperm can be released directly into the air
- DBecause they are too large to fit inside the body
Which feature of an egg cell is an adaptation that ensures only one sperm fertilises it?
- AA jelly coat that changes at fertilisation
- BEnergy stores in the cytoplasm
- CA flagellum that moves it away from sperm
- DEnzymes in an acrosome
A sperm head is about 5 μm long and an egg cell is about 0.1 mm across. How many times wider is the egg than the sperm head?
- A20
- B2
- C50
- D200
A man's sperm have normal heads but very few mitochondria in the midpiece. What is the most likely effect on fertility?
- ASperm swim poorly, so fewer reach the egg
- BSperm cannot digest the jelly coat
- CSperm nuclei cannot fuse with the egg nucleus
- DToo many sperm enter each egg
Both oviducts of a woman are blocked part-way along. Why is she unlikely to become pregnant naturally?
- ASperm and egg cannot meet in the oviduct
- BHer ovaries can no longer produce eggs
- CThe uterus lining cannot thicken
- DSperm cannot be deposited in the vagina
Quiz key
R is the prostate gland, which adds fluid containing nutrients. P is a testis (makes sperm), Q is a sperm duct (carries sperm) and S is the urethra (carries semen or urine out).
The urethra carries urine from the bladder and, at other times, semen. The sperm duct carries only sperm to the urethra; the oviduct is female; the bladder stores urine.
Fertilisation usually happens in the oviduct. The uterus is where the embryo implants, the ovary releases the egg and the vagina is where semen is deposited.
The scrotum keeps the testes slightly cooler than body temperature, which is better for sperm production. Being outside makes them less protected, not more; sperm are not released into the air; size is not the reason.
Once one sperm enters, the jelly coat changes so others cannot get in. Energy stores feed the early embryo; eggs have no flagellum; the acrosome is part of the sperm.
0.1 mm = 100 μm, and 100 ÷ 5 = 20. 2 and 200 come from using 10 μm or 1000 μm for 0.1 mm; 50 comes from dividing 100 by 2.
Mitochondria release energy by respiration for the flagellum; with few of them, sperm swim weakly. Digesting the jelly coat depends on acrosome enzymes; nuclear fusion does not depend on midpiece mitochondria; the egg's jelly coat still blocks extra sperm.
The egg travels down and sperm travel up the oviduct, where fertilisation happens; a blockage keeps them apart. The ovaries still release eggs, the lining still thickens, and sperm can still be deposited in the vagina.
What to project
The student lesson embeds these tabs. Open them full screen on the projector; every slider has a drag handle on the stage.
Slides for this lesson
A projectable deck for every pack is on the way. Until then, present the student lesson full screen: its sections, figure and lab tabs follow the same order as the plan above.