Genetic Ratios and Blood Types

The video tutorial explains sickle-cell anemia, a genetic condition where red blood cells change shape. It covers the genetic dominance of normal red blood cells over sickle-cell ones and discusses how heterozygous individuals are resistant to malaria. The tutorial sets up a genetic cross between a man with type O malaria-resistant blood and a woman heterozygous for type B blood. It demonstrates forming gametes using the FOIL method and analyzing a Punnett square to determine phenotypic and genotypic ratios of the offspring.

What is the genetic dominance relationship between normal and sickle-cell shaped red blood cells?

• Both are co-dominant

• Normal is recessive to sickle-cell

• Sickle-cell is dominant to normal

• Normal is dominant to sickle-cell

What advantage do heterozygous individuals have concerning malaria?

• They are more susceptible to malaria

• They are resistant to some strains of malaria

• They have no advantage

• They are immune to all diseases

What is the blood type of the man in the genetic cross?

• Type O

• Type AB

• Type A

• Type B

What is the genetic status of the woman regarding the sickle-cell trait?

• Homozygous recessive

• Heterozygous

• Homozygous dominant

• Carrier

Which method is used to determine the gametes in this genetic cross?

• FOIL method

• Cross-multiplication

• Subtraction method

• Addition method

How many unique gametes does the man produce?

• Four

• Three

• Two

• One

What is the phenotypic ratio of type B normal offspring?

• 1:1

• 2:2

• 3:1

• 4:0

What is the genotypic ratio of the offspring?

• 3:1:1:1

• 2:2:1:1

• 1:1:1:1

• 4:0:0:0

What is the phenotypic ratio of type O normal offspring?

• 4:0

• 3:1

• 2:2

• 1:1

What is the significance of a 1:1 ratio in genetic crosses?

• It shows equal probability of two outcomes

• It indicates a mutation

• It suggests incomplete dominance

• It means one trait is dominant