Sexual vs asexual reproduction, the reproductive systems, the menstrual cycle, fertilisation and development, birth control, HIV/AIDS and gonorrhoea.
7 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
Every one of us began as a single cell smaller than a full stop. Here’s the science of how.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
One parent; mitosis; identical offspring (budding, binary fission, vegetative propagation).
Two parents; gametes (meiosis) fuse; variation.
Follicle develops → lining repairs → ovulation (~day 14) → lining shed if no fertilisation.
Fusion of male and female gamete nuclei to form a zygote — in the oviduct.
Exchange of O₂/nutrients (to fetus) and CO₂/urea (to mother); barrier to many pathogens; makes hormones.
Barrier, hormonal, IUD, surgical (vasectomy, tubal ligation — most effective), natural.
HIV (RNA virus); antiretrovirals (e.g. AZT historically); control by condoms, monogamy, testing; prevention by abstinence.
UNAIDS 2024: ≈340 000 living with HIV; ≈15 000 new infections; ≈74% on ART; AIDS deaths down 62% since 2010.
The kind of support a teacher gives after the lesson: worked examples to attempt first, a board illustration, key terms, common misconceptions and memory aids.
Try it in your notebook first, then reveal the solution one step at a time.
Try it in your notebook first, then reveal the solution one step at a time.
The placenta lets materials pass between mother and fetus — but their blood never mixes.
The path of sperm: SEVEN UP — Seminiferous tubules, Epididymis, Vas deferens, Ejaculatory duct, (Nothing), Urethra, Penis.
The Caribbean has led the world in stopping HIV passing from mothers to babies. Cuba was the first country validated by WHO for eliminating mother-to-child transmission (2015), followed in 2017 by Anguilla, Antigua and Barbuda, Bermuda, the Cayman Islands, Montserrat, and St Kitts and Nevis.
Using your textbook, make a month-by-month timeline of pregnancy showing when the heart starts beating, when limbs form and when the fetus can hear.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better.
Write full answers, then reveal the mark scheme and tick the points you earned (25 marks in total). Your answers are saved on this device.
Question 1 [15 marks]
Janet does not want to become pregnant. Table data from UNAIDS for the Caribbean (2020): 330 000 living with HIV; 13 000 new infections; 6 000 AIDS-related deaths; 220 000 accessing treatment.
(a) List FOUR birth control methods and outline how TWO of them prevent pregnancy. [6]
(b) Calculate the percentage of HIV-positive people in the Caribbean who did NOT access treatment in 2020. [2]
(c) Suggest TWO reasons people with HIV may not access treatment. [4]
(d) Explain why people with AIDS may die from an opportunistic infection such as TB. [3]
Question 2 [10 marks]
Reproduction in humans.
(a) Describe how male gametes reach female gametes in humans. [2]
(b) Explain why a human embryo does NOT have large nutrient stores but a plant embryo does. [4]
(c) Suggest FOUR reasons a couple may choose vasectomy rather than tubal ligation. [4]
Find these in your own past-paper booklets for extra timed practice. The practice above is adapted from them.