Heredity: passing information on
Every cell in you carries a set of instructions that came half from each parent. Heredity is the story of how that information is copied, shuffled and passed on.
Lesson overview
What you'll learn in this lesson
Understand heredity as the process by which genetic information is transmitted from one generation to the next
Key learning points
- • DNA, genes and chromosomes
- • Alleles and characteristics
- • Gametes and fertilisation
- • Inherited and environmental variation
This lesson at a glance
- 30 minutes
- 25 parts to scroll through
- 4 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 25
Visual introductionPicture this
Heredity: passing information on
Every cell in you carries a set of instructions that came half from each parent. Heredity is the story of how that information is copied, shuffled and passed on.
In a nutshell
Understand heredity as the process by which genetic information is transmitted from one generation to the next
What you already know
Part 2 of 25
Before we start
What you already know
You should already know that cells contain a nucleus and that living things reproduce.
Key words
Part 3 of 25
Key words
Words you'll need today
- Gene
- A section of DNA coding for a characteristic.
- Chromosome
- A long thread of DNA in the nucleus.
- Allele
- A version of a gene.
- Variation
- Differences between individuals of the same species.
Reset break
Part 4 of 25
Pause
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Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 5 of 25
Learning cycle 1 of 2
Where the information sits
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 6 of 25
Learn
DNA, genes and chromosomes
DNA is a long molecule coiled into chromosomes inside the nucleus. A gene is a section of that DNA carrying the code for one characteristic. Human body cells contain 23 pairs of chromosomes, one of each pair from each parent. The full set of genetic information is the genome, and every body cell carries the same copy.
Explore the idea
Part 7 of 25
Learn
Alleles and characteristics
Most genes come in different versions called alleles. Because chromosomes come in pairs, you carry two alleles for most genes. A dominant allele shows its effect even if only one copy is present; a recessive allele only shows when both copies are recessive. This is why a characteristic can skip a generation and reappear.
Reset break
Part 8 of 25
Pause
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Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 9 of 25
Quick check
Part 10 of 25
Learning cycle
Part 11 of 25
Learning cycle 2 of 2
How it is passed on
A short piece of teaching, then a check to make sure it has landed.
Reset break
Part 12 of 25
Pause
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Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 13 of 25
Learn
Gametes and fertilisation
Gametes carry only one chromosome from each pair, so a sperm and an egg each supply half the set. At fertilisation the halves combine and the full number is restored. Which chromosome from each pair ends up in a particular gamete is essentially random, which is why siblings with the same parents are not identical.
Explore the idea
Part 14 of 25
Learn
Inherited and environmental variation
Some variation is inherited, some comes from the environment, and much is a combination. Eye colour is inherited; a scar is environmental; height depends on both genes and nutrition. Mutations are changes in the DNA code: most have no effect, some are harmful, and a very small number give an advantage, which is where natural selection begins.
Quick check
Part 15 of 25
Reset break
Part 16 of 25
Pause
That's sitting 4 of 6 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 17 of 25
Common mix-ups
Part 18 of 25
Common mix-ups
Things people often get wrong
- People often use gene and chromosome to mean the same thing. A chromosome carries many genes.
- People often think identical twins must be identical in every way. They share DNA, but environment still causes differences.
Challenge round
Part 19 of 25
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Reset break
Part 20 of 25
Pause
That's sitting 5 of 6 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 21 of 25
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
The full set of ____ information is the genome, and every body cell carries the same copy.
Challenge round
Part 22 of 25
Game · Recall cards
A gene is...
Card 1 of 4
Exit quiz
Part 23 of 25
Exit quiz
Show what you've learned
6 questions, marked together at the end. Nothing is timed.
1. Chromosomes are found in the...
2. Alleles are...
3. Gametes contain...
4. Siblings differ genetically mainly because...
5. A mutation is...
6. Height is best described as...
Mastery quiz
Part 24 of 25
Marked quiz
End of lesson quiz: Heredity: passing information on
4 questions, marked with the reasoning shown. No timer.
1. A gene is...
2. Human body cells contain...
3. A recessive characteristic shows when...
4. Which is purely environmental variation?
Lesson round-up
Part 25 of 25
Lesson round-up
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