16

Question 1

L aw of segregation

Answer 1

When gametes form, alleles are separated so that each gamete carries only one allele for each gene

Question 2

Law of independent assortment

Answer 2

The segregation of alleles for one gene occurs independently to that of any other gene

Question 3

Law of dominance

Answer 3

Some alleles are dominant while others are recessive; an organism with at least one dominant allele will display the effect of the dominant allele.

Question 4

Small differences between genes

Answer 4

Make u unique

Question 5

Differences in gene is called

Answer 5

Allele

Question 6

What is an allele

Answer 6

An allele is an alternative form of a gene (one member of a pair) that is located at the same place on a chromosome.

Question 7

Recombination:

Answer 7

More chances allleles are going to assort independently ??
- meiotic recombination ‘shuffling the pages’ during sperm formation
- swapping info of homologous chromosomes
- results in a mix of DNA

Question 8

Exception to the law if independent assortment

Answer 8

• when two genes are close together on a chromosome - genetic linkage

Question 9

Recessive allele is a version of the gene that does not encode …

Answer 9

A functional protein

Question 10

Heterozygous recessive mutation (Aa)

Answer 10

• one parents stopped working
• the other can mask it
• functional copy covers
• will have 50% less protein

Question 11

Homozygous recessive mutation (aa)

Answer 11

• pathway can’t work
• functional protein isnt there so you pathway stops and you get an accumulation of the precursors
• down stream proteins are made but because there is noting to work on they don’t do anything inside the cell

Question 12

E Palme of the recessive non functional protein in the flowers

Answer 12

• if you have one functional will still produce a pink flower

Question 13

We inherit a ____ combination of alleles form out parents

Answer 13

Unique

Question 14

The DNA between two people is about ___% equal

Answer 14

99.4

Question 15

How many places does DNA vary in humans

Answer 15

20 million (0.6% of the total 3.2 billion)

Question 16

_% of differences (________ differences) might affect how our genes funciuton

Answer 16

5% of these differences (1 million differences) might effect how our genes function

Question 17

Phenaylalanine breakdown

Answer 17

• accumulation
• two non function genes from parents

Question 18

Phenylalanine breakdown pathway

Answer 18

• people with non functional enzyme in each step exist- all have different outcomes

Question 19

What is occurs when protein 5 in not produced for the breakdown of phenylanine ?

Answer 19

Alkaptonuria

Question 20

What happens when a defect in the enzyme that breaks phelynine down into tyrosine stops working?

Answer 20

Defect in this enzyme leads to accumulation of phenylamine to a condition called phenylketonuria
1 in 10,000 people (5 babies a year)

Question 21

What is the newborn metabolic screening programme?

Answer 21

• screeens newborn babies for 28 metabolic disorders

Question 22

How many babies a year have a metabolic disorder or condition

Answer 22

45

Question 23

What can phenylketonuria - inablitlaty to break down phenylalanine - (PKU) lead to?

Answer 23

• Interlectual disablilty
• seizes
• behavioural problems
• mental disorders

Question 24

What enzyme breaks down phenylalanine into tyrosine

Answer 24

Phenylalanine hydroxylase

Question 25

In phenealinine breakdown, where is it worst to stop in the pathway

Answer 25

• can’t breakdown in first step = worst consequences
• can’t break down in last step = black urine = not very bad

Question 26

What do othe enzyme do if phenalynne can’t be converted to tryrosine

Answer 26

converted into other compounds
- build up of other compounds
- build up of phenylanene and other enzymes

Question 27

Why is it bad if tyrosine can’t be produced form phenalyalaine

Answer 27

• tyrosine is precursors for other elements such as dopamine, noradrenaline and neruotansitmmers there for a decrease in those and that leads to other consequences

Question 28

Consequence in production / not production from phenlanine not being broken down

Answer 28

Things at top of diagram are toxic

Question 29

Phenotype can be affected by…

Answer 29

Your environment

Question 30

In PKU individuals what can you do to prevent interlectal disability and associated problems

Answer 30

• a low phenylalanine diet
• avoid all high protein foods
• limited natural protien (less then 10g)

Question 31

Can get around our genetics by..

Answer 31

… changing our environment

Question 32

Some people have a non-functional enzyme thus they can’t breakdown phenylalanine but they have a normal IQ..how?

Answer 32

• Phenylanina is transported across the blood-brain barrier
• genetic variation means the efficient of this transporter differs between individuals
• Individuals with less efficient transporters have lower levels of Phe in the brain and less damage (higher IQ)
  (Lower expression of transporter rather then it not working)

Question 33

Environment determines

Answer 33

How some genetic differences affect us

Question 34

Most variation in out gene isnt in the coding region.. where is it?

Answer 34

• in the regions that regulate the sequence, regions where transcription factors bind

Question 35

Reduction in the expression of the transporter that takes pheneelanine into the brain is a result of..

Answer 35

• reduced expression is not from a knock out of a gene but instead it is influenced by variation in regularity seuqaences and transcription factors