Genetics And Family History

Question 1

Describe the structure of DNA

Answer 1

Double stranded, made up of a sugar (deoxyribose), nucleotide and a phosphate sugar

Question 2

Name the four bases of DNA and which pairs with which

Answer 2

Adenine, Thymine, Guanine, Cytosine
AT C and G

Question 3

Describe the bonding patterns of DNA

Answer 3

Strand starts from 5th carbon to 3rd carbon
Adenine and thymine have 2 hydrogen bonds
Cytosine and Guanine have 3 hydrogen bonds
Nucleotides form phosphates backbone

Question 4

Describe the semi conservative DNA replication

Answer 4

Helicase unzips DNA strands by breaking the hydrogen bonds between base pairs
Primase rebuilds the new template from the old template by making a small piece of RNA as a primer to start rebuilding the strand

Question 5

Describe the structure of RNA

Answer 5

Sugar is ribose, bases are adenine, uracil, cytosine and guanine
Single stranded

Question 6

Define phenotype

Answer 6

Observable physical property of an organism

Question 7

Describe the function of RNA

Answer 7

Regulating gene expression
Certain viruses use RNA as their genomic material
Found in the cell’s nucleus, cytoplasm and organelles

Question 8

Define chromosomes

Answer 8

The structure made of DNA that codes for all the characteristics of an organism

Question 9

Define histones

Answer 9

Proteins which give structure to the long strand of DNA

Question 10

karotype definition

Answer 10

collection of chromosomes

Question 11

describe diploid cells

Answer 11

contain 23 pairs
produced from mitosis, two genetically identical daughter cells

Question 12

describe haploid cells

Answer 12

gametes
contain 23 chromosomes
made by diploid cells via meiosis
producing 4 non-identical cells
have variation

Question 13

define a gene

Answer 13

a section of DNA that codes for a particular protein
variations for each gene

Question 14

define codons

Answer 14

chains of three base groupings, e.g ATT, GCC, CGT

Question 15

define alleles

Answer 15

different versions of the same gene
inherit two alleles
homozygous = indentical alleles
heterozygous = different

Question 16

define mutation

Answer 16

changing of bases in the genetic code
protein produced is deformed

Question 17

examples of mutations

Answer 17

single mutations in bases
chromosomal abnormalities

Question 18

phenotype definition

Answer 18

observable physical property of an organism

Question 19

examples of single gene autosomal dominant disorder

Answer 19

achondroplasia, huntingdon’s disease

Question 20

examples of single gene autosomal recessive disorder

Answer 20

sickle cell, cystic fibrosis

Question 21

examples of sex linked inherited diseases

Answer 21

x linked, haemophilia

Question 22

define co-dominance

Answer 22

genes that share the effect (phenotype) between two alleles

Question 23

multiple allele definition

Answer 23

genes that have more than two alternate forms e.g. ABO blood groups

Question 24

define polygenic

Answer 24

several genes are responsible for any given trait
e.g. eye, hair colour, diseases: diabetes, heart disease

Question 25

multifactoiral definition

Answer 25

complex interaction of genes with the environment e.g. cigarette smoke, sunlight