IGCSE Biology Paper-2: Specimen Questions with Answers 198 - 199 of 203

Question 198

Edit

Question

MCQ▾

Which combination of sex chromosomes in the sperm and the egg will produce a male child?

Choices

Choice (4)
a.sex chromosome in sperm-Y, sex chromosome in egg-X
b.sex chromosome in sperm-X, sex chromosome in egg-X
c.sex chromosome in sperm-X, sex chromosome in egg-Y
d.sex chromosome in sperm-Y, sex chromosome in egg-Y

Answer

a.

Explanation

  • The sex chromosomes are also known as Allosomes heterosomesor . In females, the sex chromosomes are XX and in males, they are XY.
  • The Y chromosome in human determines the maleness. It carries a gene ‘Sry’ TDF (sex determining region of Y-chromosome) which codes for a product called (Testis determining factor). TDF is required for the development of male sex and its absence leads to the femaleness.
Sex chromosomes

Sex Chromosomes

Loading image

Question 199

Edit

Question

MCQ▾

Why is yeast used in bread making?

Choices

Choice (4)
a.Aerobic respiration produces alcohol.
b.Aerobic respiration produces lactic acid.
c.Anaerobic respiration produces carbon dioxide.
d.Anaerobic respiration produces alcohol.

Answer

c.

Explanation

  • Bread is fermented using Baker’s yeast (Saccharomyces cerevisiae). ‘Saccharomyces Cerevisiae used for bread making commonly called as brewer’s yeast is also used for fermenting malted cereals and fruit juices to produce ethanol.
  • Depending on the type of raw material used for fermenting & type of processing, different types of alcoholic drinks are obtained.
Anaerobic respiration produces carbon dioxide

Anaerobic Respiration Produces Carbon Dioxide

Loading image