Unit 2-KA4

Question 1

Give the purpose of antenatal screening

Answer 1

Identifies risk of a disorder before birth
Involves testing for disease-conditions in a fetus before it’s born so that further tests and prenatal diagnosis can be offered

Question 2

Give two examples of antenatal screening procedures

Answer 2

Ultrasound imaging/scanning-
Amniocentesis
Chorionic Villus Sampling
Biochemical tests-blood/urine

Question 3

Give two uses of ultrasound imaging obtained by the use of ultrasound scanners

Answer 3

To produce dating scan-
8-14weeks
stage of pregnancy
To produce an anomaly scan-
18-20weeks
detect serious physical abnormalities

Question 4

Give the name of an image of an individual’s chromosomes arranged in homologous pairs

Answer 4

Karyotype

Question 5

Explain the difference between a screening test and diagnostic test

Answer 5

Screening-
identifies the risk of disorder

Diagnostic-
confirms presence of disorder

Question 6

Give one characteristic of a family tree that would suggest to a geneticist that the condition or gene disorder being investigated was autosomal recessive

Answer 6

Autosomal recessive-
expressed relatively rarely in the offspring
affects males and females equally
may skip generations

Question 7

Give one characteristic of a family tree that would suggest to a geneticist that the condition or gene disorder was sex-linked and recessive

Answer 7

Sex-linked recessive-
Males are affected more often than females
Male offspring receive the condition from their mother

Question 8

Amniocentesis vs Chorionic Villus Sampling

Answer 8

CVS-
carried out earlier in pregnancy
higher chance of miscarriage than amniocentesis
cannot detect neural tube defects