EQ's

Question 1

Describe how the Human Genome Project has helped establish a classification relationship between 2 species.

Answer 1

1. The DNA from both species is sequenced
2. The DNA is then compared for similarities and differences
3. The higher the number of similarities the more closely related the series

Question 2

What happens to genetic material before the cell divides?

[1 mark]

Answer 2

It copies itself

Question 3

Give three reasons why mitosis is important for organisms

[3 marks]

Answer 3

1) For growth
2) For repairing damaged tissues
3) For asexual reproduction

Question 5

Explain how offspring are produced by sexual reproduction

[3 marks]

Answer 5

Two parents are involved

The male gametes and female gametes are fused in fertilisation to produce a diploid cell

The genetic information from the male and female are mixed, this leads to variety in offspring

Question 6

Spider plants can reproduce asexually. Give three advantages of spider plants being able to reproduce asexually

[3 marks]

Answer 6

Only one parents required

More time and energy efficient

Produces many genetically identical offspring rapidly

Question 7

What does a gene code for?

[1 mark]

Answer 7

a sequence of amino acids

Question 8

Explain how protein is synthesised from a chain of bases in DNA

[3 marks]

Answer 8

Bases work in triplets

Each triplet of bases codes for an amino acid

A sequence of amino acids make a protein

Question 9

Mutations change the structure of proteins during cell division.

What might be the effect on the protien of the changed structure?

Answer 9

The protein wouldn’t function properly

Question 10

Outline the function of genes

[2 marks]

Answer 10

They code for the specific sequence of amino acids

To rpoduce specific proteins

Question 11

What is meant by the term genome?

[1 mark]

Answer 11

The entire genetic makeup of an organism

Question 12

Give one example of why it is important for scientists to understand the human genome

[2 mark]

Answer 12

To help them understand the genes that lead to inherited diseases so that they can develop effective treatments for them

Question 13

Explain how DNA bases code for a specific chain of amino acids

[2 marks]

Answer 13

Each triplet base codes for a specific amino acid

The order of the bases codes for the order of the amino acids in the chain

Question 14

Describe one role that non-coding DNA plays in protein synthesis

[1 mark]

Answer 14

Switch genes on and off

Question 15

Describe the process that takes place at the site of protein synthesis to produce chains of amino acids

[3 marks]

Answer 15

Amino acids are brought to the ribosome

By carrier molecules

The ribosome reads the triplet bases on the mRNA gene and uses this to join together the correct amino acids in the correct order

Question 16

Explain what happens to a chain of amino acids once it has been assembled

[2 marks]

Answer 16

The chain folds into a unique shape

Which determines its function and allows it to do its job

Question 17

Outline the role of two types of protein found in the human body

[4 marks]

Answer 17

Enzymes

Are biological catalysts which increase the rate of chemical reactions

Hormones

Carry chemical messages around the body through the blood

also structural proteins like collagen which provide structure and support

Question 18

Explain how mutations lead to a chainge in protein synthesis

[3 marks]

Answer 18

Mutations change the sequence of bases in a gene

The bases code for the sequence of specific amino acids in a specific protein

Change in the amino acids leads to a change in the protein

Question 19

Suggest one possible effect of a mutation that changes the shape of a structural protein

[2 marks]

Answer 19

A mutation will causet eh structural protein to lose its strength

This means that it will not be able to proveide structure and support

Question 20

Suggest one possible effect of a mutation in a gene which codes for a particular protein

[3 marks]

Answer 20

The mutation will change the shape of the active site

This means that the substrate will not be able ot bind to the enzyme

This means that the enzyme can no longer catalyse chemical reactions

Question 21

Explain how a fertilised egg cell has the correct number of chromosomes

[2 marks]

Answer 21

The two haploid gametes from the male and female fuse together

So the fertilised egg has the diploid number of chromosomes

Question 22

Describe the results of meiosis

[3 marks]

Answer 22

4

genetically non-identical

haploid cells called gametes

Question 23

What happens to the cells in an embryo as it develops in order to from a whole organism?

[1 mark]

Answer 23

The cells differentiate into different types of cell

Question 24

Give two advantages of asexual reproduction over sexual reproduction

[2 marks]

Answer 24

It is less time and energy consuming

It produces many offspring rapidly in favourable conditions

Question 25

**Explain why sexual reproduction increases chances** of a **population surviving** | [**4 marks**]

Answer 25

**Sexual reproduction** produces **variation** in **offspring** **Variation** allows them to **adapt** to **changes** in the **environment** Individulas with **favourable variations** will **survive** and **reproduce** And **pass the gene** onto **future generations**

Question 26

**Give one way** you can tell that the **allele** for a gene is **not dominant** | [**1 mark**]

Answer 26

**Carriers** of the **disease do not have** the **disease**

Question 27

**Explain** how **evolution occurs** by **natural selection** | [**4 marks**]

Answer 27

There is **variation** in a **species** due to **random genetic mutations** These **variations** in **alleles** allow individuals in a species to **adapt** to **changes** in the **environment** These indiviulas are then **more likely** to **survive** and **reproduce** And the **advantageous alleles** will be **passed on** and **inherited** by their **offspring**

Question 28

**What** is meant by **artificial selection**? | [**2 marks**]

Answer 28

Choosing the **best examples** of **animals/plants** and **breeding them together** To produce the **desired characterisitcs**

Question 29

**Suggest** why **pure pedigree dogs** are **more susceptible** to **genetic defects** | [**1 marks**]

Answer 29

There is **reduced variation** in the **gene pool** (in pure bred animals)

Question 30

**Describe** how **characterisitcs** are **artificially selected** | [**3 marks**]

Answer 30

1. **Select** a **male** and **female** in a **population** with the **desired characteristics** and **breed** them together 2. **Select** the **offspring** which **inherited** the **desired characteristics** and breed them together 3. **Repeat** the process until **all** the **offspring** have the **desired characteristics**

Question 31

A way to **protect** plants is to introduce a **gene** into the crop plant. The gene, which is **found** in **bacteria**, produces a **poison** that **kills** the **insects**. **Explain** how a **plant** is made **resistant** to the **insects** by **genetic modification** | [**4 marks**]

Answer 31

1. **Select** the **gene** from the **bacteria** that produces a poison that kills insects 2. **Cut out** and **isolate** the gene using **enzymes** 3. **Insert** the gene into a **small circle** of **plasmid DNA** to form a **recombinant plasmid** 4. **Transfer** the **desired gene** into the **target plant** at an **early stage** of its **development** so that it **develops WITH** the **deired characteristic**

Question 32

**Give two reasons** why **people** may have **concerns** about **introducing new genes** into crop plants. | [**2 mrks**]

Answer 32

There will be **concerns** about the **effects** of **eating** the plant on **HUMAN health** There will be concerns of the **transferred gene** getting into **surrounding species** in the **ecosystem**

Question 33

**Give three advantages** of **producing** a **GM crop** | [**3 marks**]

Answer 33

**Resistance** to **disease** **Resistance** to **insect attacks** **Increased crop yield**