Genetics: Mutations

Question 1

What are mutations?

Answer 1

These are spontaneous changes in the geneti make up of an organism.

Question 2

What are the factors that cause mutation?

Answer 2

Radiations eg. x rays, beta rays
Chemicals eg. mustard gas, ethyl methane,
Heavy metals eg. Mercury and lead

Question 3

What is chromosomal mutation?

Answer 3

Changes in the structure or number of chromosomes .

Question 4

Types of chromosomal mutations?

Answer 4

Deletion - a section of the chromatid breaks off and fails to reconnect .
Duplication - a section of a chromatid replicated and adds on extra genes.
Inversion- occurs when a chromatid breaks off and when rejoining the piece rotates and rejoins in an inverted position .
Translocation - occurs when a section of a chromatid attaches to another chromatid of another chromosome.
Non disjunction - occurs when there’s and addition or loss of one or more chromosomes.

Question 5

Examples of disorders caused by chromosomal mutation?

Answer 5

Down syndrome
Tumors syndrome
Polyploidy-Polyploidyis a condition whereby an organism has more than two complete sets of chromosomes in all cells.
Klinefelters syndrome

Question 6

What is gene mutation?

Answer 6

Are Changes in single dna bases, or small deletions and rearrangements.

Question 7

Name 3 types of gene mutations

Answer 7

Deletion, substitution, Inversion.

Question 8

Define substitution

Answer 8

a mutation in which one Nucleotide is replaced by a different Nucleotide. Causes sickle cell anaemia and albinism

Question 9

Gene mutation disorders

Answer 9

Haemophilia
Color blindness
Albinism sickle cell anaemia

Question 10

Characteristics of prokaryotic DNA:

Answer 10

• Is found freely in the cytoplasm (within a region called the nucleoid)

• Is naked (i.e. not bound with proteins and therefore doesn’t form chromatin)

• Genomes are compact (contain little repetitive DNA and no introns)

• Contains extra-chromosomal plasmids

• Is circular in shape

Question 11

Characteristics of eukaryotic dna

Answer 11

• Is contained within a nucleus

• Is bound to histone proteins

• Genomes contain large amounts of non-coding and repetitive DNA (including introns)

• Do not contain plasmids (but organelles such as the mitochondria may contain their own chromosomes)

• Are linear in shape

Question 12

Nucleic acids are made of small units called?

Answer 12

Nucleotides

Question 13

Each Nucleotide consists of?

Answer 13

5-carbon sugar
Phosphate molecule
Nitrogenous bases

Question 14

List five Nitrogenous bases?

Answer 14

Adenine, cytosine, thymine (in dna only), guanine, uracil (only in rna)

Question 15

How do the Nitrogenous bases arrange themselves

Answer 15

c - G
A -T
T - A

Question 16

List four differences between dna and rna

Answer 16

Dna - Rna
Contains deoxyribose sugar - contain ribose sugar
Has thymune- has uracil
Double stranded- single stranded
Enclosed within the nucleus - found within the nucleus and cytoplasm.