Mutations

Question 1

What is a:

Mutation

Answer 1

• A rare random change in DNA
• Can result from a variant which is inhereted by future generations
• Can have no effect, be harmful, or in the rare case beneficial

Question 2

Why do some:

Mutations have no effect

Answer 2

• If the protein from a mutated gene produced works just as well as the proetin from a non-mutated gene
• e.g. multiple amino acids are the same even with a different base

Question 3

What are the different types of:

Mutations

Answer 3

• Substitution - when a single base in the DNA sequence is swapped for another
• Deletion - losing a base in the sequence
• Duplication - on or more bases are duplicated
• Inverse - order of bases changed

Question 4

What increases the:

Chances of mutations

Answer 4

• Ionising radiation and chemical mutagens

Question 5

What is the:

Model answer of Natural selection

Answer 5

1. Genetic variation is caused by random mutations present in the acenstral population
2. There is competition within the population
3. The individuals with characteristics suited to the enivornment are more likely to survive and reproduce - Survival of the fittest
4. These survivors will pass on their alleles for improved adaptations to their offspring who will also show this benificial variation
5. The frequency of this allele will increase over the next few generations

Question 6

Who came up with:

Natural selection

Answer 6

charles Darwin

Question 7

What are:

Anti-biotics

Answer 7

• Chemicals usually produced by fungi
• Kill bacteria by preventing cell wall formation and given to patients with a bacterial infection

Question 8

What are:

Pathogens

Answer 8

Species that causes disease or infection

Question 9

What is:

Selective breeding

Answer 9

• The process by which humans breed plants or animals with desired characteristics
• Selection of desired characterstics by humans
• Cross-breeding of male and female with desired characteristics
• selection of offspring showing desired characteristics
• Repeating the process ofver many gneerations until allele for desired characteristic increases in frequency

Question 10

What is the:

Selective breeding present in crop and animals

Answer 10

• Crop - Higher crop yield and more resilience to insects and disease
• Animals - fitter or higher milk, meat or egg yield leading to better suited to surviving poor cliamtes

Question 11

Issues associated with:

Selective breeding

Answer 11

• Less genetic variation
• Losing useful alleles
• Reduces the ability of the individual to respond to changes in the environment leading to the accumulation of harmful characteristics

Question 12

What is:

Genetic engineering

Answer 12

• Deliberate modification of the genetic material of a living organism
• Transgenic organisms have a gene from another specie

Question 13

Name an example of:

Genetic engineering

Answer 13

Golden rice, grown in the phillipines and it is modified to have vitamin A, which is good for vision in the dark. Comes from carrots

Question 14

What are the advantages of:

Cloning

Answer 14

• All offspring are genetically identical therefore if you have an advantageous trait, all offspring have it
• reproduction is faster - only requires a member

Question 15

What is:

Cloning

Answer 15

• Production of genetically identical organisms
• Mitosis of cells to produce identical ones e.g. strawberry runners

Question 16

Disadvantages of:

Cloning

Answer 16

offspring are genetically identical and can all be susceptible to the same disease
Genetic faults will be passed down to all clones

Question 17

Types of:

Cloning in plants

Answer 17

• Runners
• cuttings
• potatoes
• bulbs

Question 18

what are:

Cuttings

Answer 18

When farmers reproduce plants by cutting from the parent, dipping it in rooting powder and plant it with a plastic bag over it

Question 19

What is:

Tissue culture

Answer 19

• Also called micropropagation
• tissue sample is sterilised using bleach to kill microbes from parent plant and put into agar growth medium, with nutrients and auxins
• Encourages growth (example)
• Samples called explants
• Samples develop into small plantlets
• These are posted in compost, with controlled conditions
• Produces large quantities of genetically identical plants

Question 20

Steps for:

animal cell cloning

Answer 20

1. Mature ovum
2. Remove haploid nucleus, forming an enulceated egg
3. Diploid adult cell
4. Remove diploid nucleus
5. Fuse it with empty egg from sheep B
6. Mild electric shock makes the cells start to divide by mitosis to form an embryo
7. Clone is implanted into uterus of sheep C
8. Leads to clone