Science - Genetics Unit

Question 1

Define Discontinuous variation

Answer 1

A feature that cannot be measured and forms distinct options e.g eye color.

Question 2

Define Continuous Variation

Answer 2

A feature that can be measured and given a value that falls into a range e.g. height.

Question 3

Define Variation

Answer 3

The differences between organisms

Question 4

Define Environmental Variation

Answer 4

Differences in organisms that are caused by its surroundings.

Question 5

Define Physical environmental factor

Answer 5

A non-living factor that affects an organism e.g. weather.

Question 6

Give an example for continuous variation and discontinuous variation and environmental variation.

Answer 6

Continuous variation: height, weight, hand span, chin shape.
Discontinuous variation: Hair color, blood groups
Environmental variation: Piercings, Streaked hair, Scars

Question 7

Define Inherited Variation

Answer 7

inherited characteristics from parents.

Question 8

How are characteristics passed on?

Answer 8

New-born baby’s characteristics are passed in the genes it has inherited from its parents.

Question 9

How do sets of genes work?

Answer 9

One chromosome of each pair comes form our mother and the other chromosome in each pair comes from our father.

Question 10

What is an Allele?

Answer 10

one member of a pair of different forms of a gene.

Question 11

How do we inherit chromosomes?

Answer 11

Egg and sperm cells are the only cells in the body to contain 23 chromosomes – they only have one copy of each pair. During fertilisation, these cells join together to form an embryo. This means that inside each cell of the embryo there are 46 chromosomes.

Question 12

Define DNA

Answer 12

Thread like strands in the nucleus of the cell; they contain the instructions for a living thing.

Question 13

Define Gene

Answer 13

A length of DNA that contains 1 inherited characteristic of an organism.

Question 14

Define Chromosome

Answer 14

A large molecule that contains genes. It is the material that transfers genetic characteristics in all life’s forms.

Question 15

Define Allele

Answer 15

Different forms of a gene.

Question 16

Compare Inherited and Environmental variation

Answer 16

• Inherited variation: Caused by genes passed down from our parents e.g. eye colour.
• Environmental variation: Caused by the conditions we live in e.g. abundance of food.

Question 17

List these into Genetic, Environmental or both variations.
- Skin colour
- Spoken language
- Strength
- Hair length
- Eye colour
- Ear size/shape
- Height
- Hair colour
- Weight
- Tongue roller

Answer 17

• Genetic:
  Eye colour
  Ear size/shape
  Height
  Tongue roller
• Environmental:
  Spoken language
• Both:
  Skin colour
  Strength
  Hair length
  Hair colour
  Weight

Question 18

What is Selective Breeding?

Answer 18

Pedigree animals (and plants) that show favourable traits are often interbred with close family members to preserve and heighten the required trait

Question 19

What do you know about DNA Structure

Answer 19

If you unravel DNA, it looks like a twisted ladder; this is called a double helix. The building blocks of DNA are called nucleotide bases; and there are 4 of them.

Question 20

How are the ATCG paired in DNA?

Answer 20

A is ALWAYS paired with T
C is ALWAYS paired with G

Question 21

Explain the Genetic Code

Answer 21

Genes use a code based on group of 3 bases. These groups of 3 are called “codons” or triplets. There are 64 different codons, and they produce 20 different amino acids. Amino acids are the raw material proteins are made from.

Question 22

Answer true or false:
A gene is a length of DNA
Identical twins have the same genes
Tongue rolling is NOT genetic
Genes contain chromosomes
There are 23 chromosomes in a gene
There are 46 genes in a living cell
Genes are passed on through blood
Half of your genes come from your male parent, half from your female parent
A strong gene is called recessive
Everyone has a DNA fingerprint which can be used to identify people
What you look like and how you work is all down to your genes

Answer 22

1. T
2. T
3. F
4. F
5. F
6. F
7. F
8. T
9. F
10. F
11. T
12. F