Human Reproductive System and Puberty

British & IGCSE › Checkpoint 6 › Checkpoint 6 Science — Complete Course

This page covers a topic that every person goes through: growing from a child into an adult. Scientists study it in the same calm, factual way that they study the heart or the lungs. Learn the correct scientific names — Checkpoint expects them, and using the proper words is the respectful way to talk about the human body.

1. The human life cycle

Every human goes through the same stages of life. The stage between being a child and being an adult is called adolescence. During adolescence the body goes through a set of changes called puberty. Puberty prepares the body so that, as an adult, a person is able to reproduce (have children). Reproduction is one of the life processes of all living things.

2. Parts of the female reproductive system

The female reproductive system is inside the lower part of the body (the abdomen). Learn each part with its job. Checkpoint usually asks you to name a part from its job, or to match a part to its job.

3. Parts of the male reproductive system

4. Puberty: what changes and why

Puberty is started by hormones. Hormones are chemicals made in the body that travel in the blood and tell organs to change. Puberty usually begins between about 8 and 13 years old in girls and between about 9 and 14 in boys, and it lasts a few years. Everyone is different: starting earlier or later than a friend is completely normal.

Some changes happen to both boys and girls, and some happen to only one. Checkpoint often gives a list of changes and asks you to sort them, so learn the table below.

Puberty can also bring emotional changes, such as mood changes or caring more about how you look. These are real and normal, but the objective asks about physical changes — so if a question says 'physical change', do not write a feeling.

5. Reading a growth graph

Checkpoint likes to join a biology topic with Thinking and Working Scientifically. A very common link here is a growth graph. The line graph below shows the height of one boy, Karim, measured on his birthday each year. (This is example data for practice.)

1. Read the axes first: x-axis = age in years, y-axis = height in cm. Each small square on the height axis is 5 cm.
2. To find the growth in one year, subtract: height at the later age − height at the earlier age.
3. The steepest part of the line shows the fastest growth — this is the growth spurt of puberty.
4. Near the end the line becomes flatter: growth slows down as the body reaches adult height.

Worked examples

Worked example 1 — Name the organ in a female that makes egg cells. [1 mark]

1. Egg cells are the female sex cells.
2. They are made and stored in the ovaries.

Answer: ovary. Common mistake: writing 'uterus' or 'womb'. The uterus is where a baby develops — it does not make eggs.

Worked example 2 — Draw a line to match each part to its job. Parts: testis, sperm duct, scrotum. Jobs: (i) carries sperm cells away from the testes; (ii) makes sperm cells; (iii) holds the testes outside the body. [2 marks]

1. Testis → makes sperm cells (ii).
2. Sperm duct → carries sperm cells away (i). The word 'duct' means tube.
3. Scrotum → holds the testes outside the body (iii).

Answer: testis–(ii), sperm duct–(i), scrotum–(iii). Mark schemes often give 2 marks for all three correct and 1 mark for one correct.

Worked example 3 — Here are four changes: voice gets deeper; growth spurt; breasts develop; hair grows under the arms. Which two changes happen to both boys and girls? [1 mark]

1. Voice getting deeper — boys only.
2. Breasts develop — girls only.
3. Growth spurt and underarm hair — both.

Answer: growth spurt and hair grows under the arms (both needed for the mark).

Worked example 4 — Use the table of Karim's heights. (a) How much did Karim grow between age 12 and age 13? (b) Between which two birthdays did he grow the most? [2 marks]

1. (a) 158 − 150 = 8 cm.
2. (b) Work out every yearly increase: 5, 5, 5, 7, 8, 7, 4, 2 cm. The largest is 8 cm.
3. So the biggest growth was between ages 12 and 13.

Answer: (a) 8 cm (b) between 12 and 13. Common mistake: choosing the highest point on the graph (age 16). The tallest height is not the fastest growth — look for the biggest increase.

Worked example 5 — Explain why the growth line on Karim's graph becomes flatter after age 15. [1 mark]

Answer: puberty is nearly finished, so his growth is slowing down / he is reaching his adult height. (Do not write 'he stopped eating' — use the science of puberty.)

Practice

All pages in this course

Start here

• Checkpoint 6 Science: The Test and How to Prepare
• Thinking and Working Scientifically: Investigations, Variables, Tables and Graphs

Biology

• The Heart and Circulatory System
• The Lungs and Respiratory System
• Human Reproductive System and Puberty
• Diseases, Hygiene and the Body's Defences
• Food Chains, Food Webs, Energy and Toxins

Chemistry

• Properties of Substances: Melting and Boiling Points, Gases, Conductors
• Reversible Changes and Dissolving
• Boiling and Evaporation
• Chemical Reactions: Reactants, Products and Evidence

Physics

• Mass, Weight and Gravity
• Force Diagrams and Forces on Moving Objects
• Floating and Sinking
• Light: Reflection and Refraction
• Electric Circuits, Symbols, Series and Parallel

Earth and space

• Rocks and Fossils
• Types of Soil
• The Rock Cycle
• The Solar System and the Phases of the Moon

Practice tests

• Checkpoint 6 Science — Practice Test 1
• Checkpoint 6 Science — Practice Test 2
• Checkpoint 6 Science — Practice Test 3