Mutations

Question 1

Chromosomal mutations VS Gene mutations

Answer 1

all/parts of chromosome is affected
When cell divide the mutated DNA will be copied and passed to the future games= future generations

Gene mutation=> changes in single gene= traits normally produced by the gene are changed or destroyed.

Question 2

How are mutations caused

Answer 2

A factor which may cause mutations if exposed ( mutagens)-> a chemical or physical agent capable of inducing changes in DNA called mutations

. Can be spontaneous caused by copying errors during DNA replication.

Question 3

What is a mutation

Answer 3

A permanent change in the base sequence-> affect the structure and function within the gene

Question 4

What are the inheritance of the mutations.

Answer 4

Somatic Mutation-> body cells/ somatic cells are involved with a mutation. ( only individual is affected)

Germline Mutation-> occur in the gamets thus mutation can be passed down to generations; either harmful, neutral or beneficial

Question 5

Define point mutation and describe the types.

Answer 5

a change to a single nucleotide during replication of DNA molecule is known as point mutation=> alter/ prevent a particular protein being made, or have no effect at all

Substitution
Inversion
Insertion
Deletion

Question 5

Types of chromosomal mutation

Answer 5

Are more detrimental in comparison to gene mutations-> this is because includes all part of chromosome, a number of geners will be affected

Duplication-> part of chromosome is copied , duplicate segments increase gene expression
Invertion-> take a part of chromosome and reverse the order.
Deletion-> a portion of chromosome is lost
Insertion->a part of chromosome is removed and added to another chromosome
Translocation-> segments of two chromosome exchange

Question 7

Describe process of Karotyping

Answer 7

1. Harvesting of cells (foetal/ white blood cells)
2. Chemically induced cell division, chromosomes then condensed and thus visible.
3. mitosis is halted to determine if chromosomes appear are sister chromatids
4. stainning and photographic chromosomes, before arranging them in order.

Question 7

Sickle Cell anaemia (gene mutation)

Answer 7

occurs because of base substitution

Consequences
-> because of base substitution mutation, amino acid changes ( GLU-> VAL) this alters the structure of haemoglobin
forms insoluble fibrous strands-> cannot carry oxygen as effectively ( tired)
thus changes the shaoe of the red blood cell to a sickle shape

may form clots within the capillaries-> blockign blood supply to vital organs causing myriad health issues.
decreased red blood cell count.

Question 8

Types of gene mutation ( only impact one base)

Answer 8

Substitution-> ATG-ACG
Invertion-> ACG-AGC
Insertion-> ATG- ATGC
Deletion-> ATG-AG

Question 9

Effects of point mutations

Answer 9

Silent mutation-> there is a change in nucelotide however doesn’t change the amino acid sequence ( certain codons may code for the same amino acids)

Missense mutations-> changes causes one amino acid to be changed in a polypeptide chain

Nonsense mutations-> Dna change which creates a premature stop codon thus truncating/ shortens the amino acid sequence.

Neutral mutations-> causes a change in an amino acid-> no change in structure or function.

Question 10

Define lethal recessive

Answer 10

recessive can occur if they are not masked by a dominant normal allele-> an individual inherits both recessive allels thus causing death to the organism.

Question 11

Tay-Sachs Disease

Answer 11

Autosomal recessive pattern
A fatal genetic disorder, occurs in children results in progressive destruction of the nervous system.

Abnormal accumulation of fatty substances in cells causes damage to nerve cells

Symptoms-> blind, cognitively impaired.