topic 3 - genetics

Question 1

What does meiosis form

Answer 1

Four daughter cells, each with half number of chromosomes and this results in genetically different haploid gametes

Question 2

What is DNA as a polymer made up of

Answer 2

Two strands coiled to form a double helix
Strands linked by a series of complementary base pairs joined together by weak hydrogen bonds
Nucleotides that consist of a sugar and phosphate group with one of the four different bases attached to the sugar

Question 3

What is the genome

Answer 3

The entire DNA of an organism and a gene as a section of a DNA molecule that codes for a specific protein

Question 4

How is DNA extracted from fruit?

Answer 4

Mash some strawberries and then put them in a beaker containing the solution of detergent and salt – mix well.
The detergent will break down the cell membranes to release the DNA. The salt will make the DNA stick together.
Filter the mixture to get the froth and big, insoluble bits of salt out.
Gently add some ice cold ethanol to the filtered mixture
The DNA will start to come out of a solution as it’s not soluble in cold alcohol. It will appear as a white stringy precipitate that can be carefully fished out with a glass rod.

Question 5

What are alleles?

Answer 5

Genesthat exist in different versions

Question 6

What does homozygous mean?

Answer 6

If an organism has two alleles for a particular gene that are the same

Question 7

What does heterozygous mean?

Answer 7

If it’s two alleles for a particular gene are different

Question 8

What does genotype?

Answer 8

Combination of the alleles you have

Question 9

What does phenotype?

Answer 9

You alleles determine what characteristics you have

Question 10

What is. A chromosome

Answer 10

thin strands of DNA

Question 11

What is a gene

Answer 11

Section of DNA

Question 12

What is dominant allele

Answer 12

Always express even if there is one copy of it

Question 13

What is a recessive allele

Answer 13

Only expressed if the individual has two copies and doesn’t have the dominant allele of that gene

Question 14

What is a gamete

Answer 14

Reproductive cell

Question 15

What is a zygote

Answer 15

Fertilized egg cell

Question 16

Most phenotypic features of the result of what?

Answer 16

Multiple genes rather than single gene inheritance

Question 17

Describe the causes of variation that influence phenotype

Answer 17

Genetic variation - caused by organisms having different alleles which can lead to differences in phenotype
This arises through mutations . Sexual reproduction also causes genetic variation since it results in alleles being combined in lots of different ways and offspring

Environmental variation – different characteristics caused by an organisms environment

Question 18

What were the outcomes of the human genome project and its potential applications within medicine

Answer 18

It helped to identify 1800 genes related to disease

Prediction and prevention of disease diseases
- many common diseases like hunters and heart disease are caused by the interaction of different genes as well as lifestyle factors
- if doctors knew what predisposed people to what diseases, we could all get individually tailored advice on the best diet and lifestyle to avoid our likely problems
Testing and treatment for inherited disorders
- scientists are now able to identify the genes and alleles that are suspected of causing an inherited disorder and much more quickly than they do in the past
- once that causes inherited disorder has been identified, people can be tested for it and it may be possible to develop better treatment or even cure for the disease
You and better medicine
- Scientist assign new drugs that are specifically detailed to people with a particular genetic variation
- they can also determine how well an existing drug work for an individual

Question 19

What are drawbacks of the medical applications in the human genome project?

Answer 19

Increase stress – if someone knew from an early age that their susceptible to a brain disease they could panic every time they get a headache
Geneism – people with genetic problems could become under pressure to not have children
Discrimination by employers and insurers – life insurance could become impossible to get if you have any genetic likelihood of serious disease
- employees may discriminate against people who are genetically likely to get a disease

Question 20

What are the rise through genetic variation within the population of a species?

Answer 20

Mutations

Question 21

What are genetic mutation have any effects on the phenotype?

Answer 21

No, not really. It’s very rare.