Chromosome abnormalities, mutations and analysis.

Question 1

Name three general types of chromosome mutation.

Answer 1

numerical,structural and mutational (related to DNA)

Question 2

What can non-disjunction cause in gametes?

Answer 2

Disomy - two going into one.

Question 3

What are germ line mutations?

Answer 3

Mutations in gametes - leads to genetic disorders in the family.

Question 4

What are somatic mutations?

Answer 4

Mutations that occur in other body cells (not germ line) and cannot be passed onto children.

Question 5

what is autosomal aneuploidy ?

Answer 5

Wrong number of chromosomes - could be 45 or 47, etc.

Question 6

what is autosomal euploidy?

Answer 6

Wrong number of chromosome pairs.

Question 7

What is balanced translocation? Where may it occur and be ok, and where would it be not ok?

Answer 7

Some genetic material is switched, but it is all still there. In somatic cells it may show no difference, but in germ line cells it may cause partial trisomy or monosomy.

Question 8

What is unbalanced translocation?

Answer 8

Not all the genetic material is there - there is too much of one and too little of the other.

Question 9

What is robertsonian translocation?

Answer 9

this occurs in acrocentric chromosomes - makes one large chromosome with lots of genes, and one tiny one with irrelevant genes which is often lost after replication.

Question 10

What is paracentric inversion?

Answer 10

Random bit on strand flips.

Question 11

What is pericentric inversion?

Answer 11

Flips around the centromere.

Question 12

What is silent DNA mutation?

Answer 12

Sometimes different codons code for one amino acid, so there may be a mutation, but the amino acid will remain the same.

Question 13

What is missense DNA mutation?

Answer 13

When there is a mutation to cause the incorrect amino acid in a sequence.

Question 14

What is nonsense DNA mutation ?

Answer 14

Mutation causes a stop sequence - so the protein chain is prematurely finished.

Question 15

What is a Frameshift mutation?

Answer 15

Deletion or insertion, causes the whole thing to be out of frame.

Question 16

What is a transition single point mutation on a DNA chain?

Answer 16

Causes base to stay the same - purine and pyrimidine stay the same.

Question 17

What is a transversion single point DNA mutation?

Answer 17

Causes purine and pyrimidine to switch.

Question 18

Name four ways to identify genetic mutation associated with disease.

Answer 18

PCR, ARMS, RFLP, Gel electrophoresis.

Question 19

What does ARMS stand for?

Answer 19

Amplification refractory mutation system .

Question 20

What does RFLP stand for?

Answer 20

restriction fragment length polymorphism.

Question 21

What does PCR require and what does it cause?

Answer 21

Primer and enzymes - produces a lot of replications of the chain of DNA

Question 22

What does gel electrophoresis do?

Answer 22

It separates DNA based on its size using an electric field. Allows us to visualise it.

Question 23

What are the advantages and disadvantages of gel electrophoresis?

Answer 23

Advantages - fast and easy

Disadvantages - needs sequence info, limited amount of product.

Question 24

What principle does RFLP work on?

Answer 24

It uses enzymes that will cut DNA at the same site.

Question 25

What else does RFLP require?

Answer 25

Electrophoresis to diagnose fragments.

Question 26

How does ARMS work?

Answer 26

Uses mutant primers and normal primers - mutant primers will amplify mutant DNA, and normal primers with amplify normal DNA.
soooooo primer design is critical.

Question 27

What does ARMS also need?

Answer 27

gel electrophoresis.

Question 28

name three autosomal aneuploidy syndromes.

Answer 28

Downs syndrome (trisomy 21)
Palau syndrome (Trisomy 13)
Edwards syndrome (trisomy 18)

Question 29

Name two sex chromosomes aneuploidy syndromes.

Answer 29

Turner syndrome (45,X)
Klinerfelter syndrome (47,XXY).

Question 30

What does downs syndrome cause?

Answer 30

facial changes
low IQ
shorter life expectancy
Alzheimers in later life.

Question 31

How is downs syndrome,patau syndrome and edwards syndrome usually caused?

Answer 31

Usually by non-disjunction from maternal origin.

Question 32

What does patau syndrome cause?

Answer 32

Facial changes,
mental retardation,
5% die in first month, few survive after one year.

Question 33

What does edwards syndrome cause?

Answer 33

severe developmental problems

most die in first year.

Question 34

What does turner syndrome cause?

Answer 34

often cause miscarriage
Females have short stature, are infertile, have neck webbing and widely spaced nipples.
Intelligence and life span is normal.

Question 35

what does klinefelter syndrome cause?

Answer 35

Tall stature,
long limbs,
males are infertile with short testes
Mild learning difficulties.

Question 36

when are chromosomal abnormalities most commonly created in developing humans?

Answer 36

first trimester- cause miscarriage.