Genetics

Question 1

What is teratology?

Answer 1

It’s the study of developmental anomalies

Question 2

What are teratogens

Answer 2

They are physical, chemical or biological which results in developmental anomalies

Question 3

What is a malformation

Answer 3

It can be said to be a type of anomaly.
It is a morphological abnormality of an organ part on of an organ or anatomica region due to perturbed morphogenesis

Question 4

Ways in which teratogenic can be identified include

Answer 4

1.Population survey
2.Retrospective or prospective studies of single malformations
3.Studying the adverse effect of drugs and chemicals

Question 5

Genetic and developmental disorders can be classified into

Answer 5

Single gene defects
Chromosomal abnormality
Error of morphogenesis
Polygenic inherited disease

Question 6

A noxious exogenous toxins that affect the preimplantation embryo does not result in malformations but ………….. usually unnoticed and perceived as healthy delayed menstrual bleeding

Answer 6

Death

Question 7

Injury during the ……….. days after fertilisation results in incomplete separation of blastomeres to yield siamese twins

Answer 7

8-10 days

Question 8

The conjoined twins can be joined at different sites

Answer 8

Craniopagus
Ischiopagus
Thoracopagus

Question 9

Sacrococcy legal teratoma is an example of

Answer 9

Asymmetric conjoined twins in which the abnormal is inside the other fetus

Question 10

A lot of complex morphological abnormalities results as a result of ……….

Answer 10

Injury during early stage of organogenesis

Question 11

The reason why organogenesis is susceptible to injury is because

Answer 11

Faulty gene activity
Exposure to exogenous antigen

Question 12

List the developmental anomalies and explain

Answer 12

Hypoplasia
Agenesis
Aplasia
Involution failure
Division failure
Dysraphic anomalies
Atresia
Heterotopia or ectopic
Dystopia

Question 13

When does organ fully form in fetal life

Answer 13

By the end of first trimester, all organs are fully formed

Question 14

At what stage of fetal life is it unlikely for morphological damage due to teratogens to occur

Answer 14

After the third month of pregnancy but functional damage and to a lesser extent structural damage can occur because organs continue to mature and restructure

Question 15

A morphological anomaly that occurs in the 2nd and 3rd trimester are……… and are caused due to ……….

Answer 15

Deformation
Mechanical damage

Question 16

Types of mechanical damage that leads to deformation are divided into

Answer 16

Extrinsic :club foot in oligohydraminos
Intrinsic :hypomobility due to CNS damage

Question 17

What is genetics?

Answer 17

It is the study of characteristics that can be passed down from one generation to another and variation in the inheritance traits

Question 18

What is the distinguishing feature of a chromosome?

Answer 18

The position of the centeromere to the whole length of the chromosome and the length of the arm on either side.

Question 19

What is the role of actin in cell division

Answer 19

It forms contractile ring that helps divide the cytoplasm into two daughter cells

Question 20

Differences between DNA and RNA

Answer 20

Single stranded vs double stranded
The nitrogen base thymine is replaced by uracil in RNA
Deoxyribose sugar vs ribose

Question 21

Differences between DNA and RNA

Answer 21

Single stranded vs double stranded
The nitrogen base thymine is replaced by uracil in RNA
Deoxyribose sugar vs ribose

Question 22

The RNA that exist in a clover-leaf like shape is

Answer 22

tRNA

Question 23

The RNA that exist in a clover-leaf like shape is

Answer 23

tRNA

Question 24

The protein synthesis machinery in the cell is ………..

Answer 24

Ribosome

Question 25

What is the heterogeneous nuclear RNA

Answer 25

It is involved in splicing process. In which all introns are removed and extrinsic or coding region are joined together to form mRNA. It's a precursor of the mRNA or mature RNA

Question 26

The three types of cells are with examples

Answer 26

Labile cells Epithelium of UT vagina skin Stable cells Liver Kidney Permanent cells Skeletal Cardiac Neurons

Question 27

The two major mutagenic chemicals are

Answer 27

Nuckeic acid analogues Alkylating agent

Question 28

A terminal deletion can be mistaken for a ...........

Answer 28

Translocation

Question 29

What are mutagenic agents?

Answer 29

Physical, chemical or biological agent that results in or associated with mutation

Question 30

There are over ............ chemicals that results in mutations

Answer 30

200 chemicals

Question 31

Some viruses have been associated with chromosomal abnormalities such as

Answer 31

Breakage Fragmentation Pulverisation Cell fusion with abnormal mitotic spindle formation

Question 32

Viruses associated with chromosomal abnormalities include

Answer 32

Herpes, measles and oncogenic biruses

Question 33

The chromosomal translocation in down syndrome exist in

Answer 33

14:21 - transmitted through mothers 21:22 - transmitted by both sexes

Question 34

The autosomal recessive disorders associated with a high degree of chromosomal instability include

Answer 34

Bloom's syndrome Ataxia telangiectasia Fanconi's anemia.

Question 35

What is the aetiology of autosomal recessive disorders associated with very unstable chromosome

Answer 35

Mutation due to faulty DNA reparative apparatus. This renders them highly susceptible to mutation

Question 36

The unaltered gene is known as........

Answer 36

Wild type gene

Question 37

The mutant and wild type gene are inherited in .............. manner

Answer 37

Stable manner

Question 38

The two types of mutations are

Answer 38

Point mutation Rearrangement affects a larger number of genes

Question 39

The commonest forms of mutations are

Answer 39

Deletion or insertion of additional genetic material

Question 40

B0thalassemia is a type of

Answer 40

Nonsense mutation

Question 41

What is the genetic basis of tay sacchs disease ashkenazi Jews

Answer 41

There is an insertion of 4 bases in the hexaminidase A gene which results in frameshift mutation

Question 42

The two types of heritable single gene disorders are

Answer 42

Mitochondrial DNA disorders Chromosomal DNA disorders