Genetics

Question 1

Name the 4 kinds of nitrogenous bases in DNA and identify the complementary base pairs…

Answer 1

Adenine = thymine
Guanine = cytosine

Question 2

Explain the relationship between genes and alleles…

Answer 2

A gene is a sequence of DNA that can be translated into a protein.

An allele is a version of a gene. We have two alleles of every gene, located on the same spot on different chromosomes. For example, the gene for eyecolor can either be the allele blue or the allele brown, but they are the same gene!

Question 3

Define genome

Answer 3

sum total of the genes present in a cell or an organism

Question 4

Define how a karyotype is made

Answer 4

The term karyotype refers to the basic map, or picture, of the number,type, and structure of the chromosomes of a cell. The karyotype is created through a process in which a cell’s mitotic division is halted or trapped during metaphase and held suspended by chemicals.

Question 5

Distinguish between sex chromosomes and autosomes

Answer 5

Autosomes are the somatic chromosomes which control the body characters or somatic characters, Whereas Sex chromosomes are the allosomes which determines sex of an individual.
For instance in man there are 46 chromosomes in which 44 chromosomes are the autosomes and 2 chromosomes are the allosomes,

Male —— 44 A + XY

Female — 44 A + XX

Question 6

Define and give three examples of sex linked characteristics

Answer 6

A trait associated with a gene that is carried only by the male or female parent. Note : In humans, the gene for colorblindness is carried by the X-chromosome.
Eg. 
-Haemophilia
-certain types of baldness
-the placement of sweat glands
-colour blindness

Question 7

what is the relationship between haploid and diploid in terms of chromosomes

Answer 7

In humans, the haploid cells have 23 chromosomes, versus the 46 in the diploid cells.

Question 8

Name the types of chromosomal abnormalities that can be identified from examining a karyotype

Answer 8

Amniocentesis
Chorionic Villi Sampling (CVS)
Screening for Abnormal DNA and RNA Sequences

Question 9

What are the 3 distinct chemical components of a nucleotide?

Answer 9

Nitrogenous base
Pentose sugar
Phosphate group

Question 10

What is the difference between prokaryotic and eukaryotic

Answer 10

Prokaryotic chromosome

• Primarily haploid
• DNA is not complexed with proteins
• Chromosomal DNA is localized in the cytoplasm.

Eukaryotic Chromosome

• Primarily diploid
• DNA is complexed with proteins forming deoxyribonucleoprotein
• Chromosomal DNA is confined within the nucleus.