Genetic Change

Question 1

electromagnetic radiation sources - mutagenic

Answer 1

Wavelengths of light

The main sources of radiation that are going to cause issues are those that are more energetic (E.G. UV, x-ray, Gamma Rays) -> ability to strip electrons from your atoms

UV radiation can directly damage your DNA

Question 2

Chemical Mutagens

Answer 2

chemicals which that cause mutations if cells are exposed to them at high frequencies or for prolonged periods of time
- > Ingested chemicals (tabbaco)
- > Environmental irritants and poisons (asbestos)

Question 3

Naturally Occurring Mutagens

Answer 3

mutagenic agents that are present at normal levels within natural environments, and may cause mutation.
- > biological - virus, bacteria, fungi
- > non-biological - metals such as mercury

Question 4

point mutation

Answer 4

a change to one nucleotide.

occur due to errors in DNA replication or occasionally due to mutagens

Question 5

Examples of Point Mutations

Answer 5

Base substitution
Neutral mutation
Missense mutation
Nonsense mutation

Question 6

Frameshift Mutation
(2 types)

Answer 6

Base insertion is when one nucleotide is added to the DNA sequence.

Base Deletion is when one nucleotide is deleted from the DNA sequence.

Question 7

Chromosomal mutations

Answer 7

a change in the arrangement or structure of a chromosome.

Question 8

Types of chromosomal mutations include:
(4)

Answer 8

Chromosomal deletion: occurs when a section of DNA is removed and not replaced

Chromosomal inversion = bases are in reverse order

Chromosomal insertion (duplication) = occurs when a portion of DNA is duplicated and inserted, increasing the number of genes on the chromosome

Chromosomal translocation =occurs when a section of DNA is moved from one chromosome to a non-homologous chromosome

Question 9

Somatic Mutations

Answer 9

a change in a DNA sequence that occurs in somatic (non-sexual) cells and may affect only part of an organism

Question 10

Germ-Line Mutation

Answer 10

occur in the sexual reproductive cells that give rise to gametes (germline cells) and these mutations ARE passed to offspring

Question 11

Coding DNA

Answer 11

is DNA that codes for products such as proteins (genes are coding DNA)

Question 12

Non-Coding DNA

Answer 12

is DNA that contains sequences that are excised from RNA and do not code for products such as proteins

Question 13

Meiosis and genetic variation

Answer 13

When gametes form, crossing over and random segregation in meiosis result in genetic recombination of paternal and maternal genes within each gamete

Question 14

Gene flow

Answer 14

when new individuals enter a population, or existing individuals leave, which may result in a change in allele frequency.

Question 15

Genetic drift

Answer 15

a change in allele frequency due to random chance. Eg a natural disaster.

Question 16

Meiosis and genetic variation

Answer 16

When gametes form, crossing over and random segregation in meiosis result in genetic recombination of paternal and maternal genes within each gamete

Question 17

What is biotechnology?

Answer 17

the use of technology to make a product or modify processes. It uses living systems to develop these products

Question 18

Polymerase Chain Reaction (PCR)

Answer 18

Used to amplify a specific region of DNA. This is particularly important since scientists often need large amounts of DNA if they are to analyse, test or use it.

Question 19

DNA Sequencing

Answer 19

Where the sequence of nucleotides (A, G, C, T) in a piece of DNA is determined.

Question 20

DNA Profiling

Answer 20

Where a person’s DNA profile is created by analysing DNA regions which are usually different between different people.

Question 21

Cloning

Answer 21

Where a genetically identical copy of a gene, tissue or organism is made.

Question 22

Potential benefits of biotechnology for society

Answer 22

Gene therapy—treat human disease,
genetically modified food—alleviate hunger,
plant banks/animal cryopreservation—maintain biodiversity
conservation, plant/algae based resources—biofuels

Question 23

Changes to the Earth’s biodiversity due to genetic techniques
long term + short term

Answer 23

Short-term: New gene combinations = increased biodiversity
Long-term: Selective breeding of certain genes = decreased biodiversity