abnormal meiosis

Question 1

abnormal

Answer 1

• chromosome abnormalities
• chromosome non-disjunction (fail to separate correctly)
• zygote (having extra or missing a chromosome, known as aneuploidy)
• syndromes
• diagnosis is identifying the nature of an even
• prognosis is predicting how the event will develop

Question 2

klinefelter’s syndrome

Answer 2

• example of aneuploidy
• extra copy of the x chromosome (xxy)
• when a sex chromosome in the egg (or very rarely a sperm) splits unevenly
• sparse body hair
• enlarged breasts
• small testicles and penis
• not very deep voices

Question 3

down syndrome

Answer 3

• extra (third) copy of chromosome 21
• during oogenesis the 21 chromosomes don’t separate properly
• two go into one rather than 1 in each daughter cell
• egg is fertilised, forming 3 21 chromosomes
• 47 chromosomes

Question 4

characteristics

Answer 4

• mental retardation
• distinctive flattened facial features
• slightly slanting eyes
• short stubby fingers and toes
• largish ears
• heart defects
• happy, loving nature

Question 5

do children with genetic abnormalities have problems

Answer 5

• slower development
• patronising attitudes and discrimination
• some may need to attend special classes

Question 6

abortion

Answer 6

• determined before had
• ultrasound or blood test
• amniocentesis

Question 7

karyotype

Answer 7

• a set of chromosomes
• shows number, shape and size of chromosomes during metaphase of mitosis
• prepared in the nuclei of cultured white blood cells
• after 7 days they are treated with a drug that arrests mitosis
• chromosomes dyed and photographed
• autosomes in human
• gonosomes x and y are placed seperately

Question 8

why are karyotypes useful

Answer 8

• shows whether cell comes from male of female

- abnormal chromosomes