At the subcellular level, starch is stored in amyloplasts in the endosperm of cereals. Two enzymes responsible for initiating starch degradation are α- and β-amylase

a) α-Amylase hydrolyzes starch chains internally to produce oligosaccharides consisting of α(1,4)-linked glucose residues

b) β-Amylase degrades these oligosaccharides from the ends to produce maltose, a disaccharide

c) α-Amylase degrades these oligosaccharides from the ends to produce maltose, a disaccharide

d)  α-Amylase hydrolyzes starch chains internally to produce oligosaccharides consisting of  β(1,4)-linked glucose residues

e) β-Amylase also converts maltose to glucose

Which of the following combination from the above statements is correct?

TLS Online TPP Program

#Question id: 12488

#Unit 8. Inheritance Biology

Retinoblastoma usually occurs as a sporadic event but in around 10% of cases there is a positive family history due to autosomal dominant inheritance. In these families the penetrance is approximately 80% (= 0.8). A woman with retinoblastoma, whose father and grandfather were also affected, has an unaffected partner with no relevant family history. Which of the following is correct regarding their children?

TLS Online TPP Program

#Question id: 12489

#Unit 8. Inheritance Biology

Achondroplasia shows autosomal dominant inheritance with complete penetrance. A man with achondroplasia has an unaffected partner of normal height. Their first two children are not affected. Which of the following is correct?

TLS Online TPP Program

#Question id: 12490

#Unit 8. Inheritance Biology

Tay-Sachs disease shows autosomal recessive inheritance. Parents of a newly diagnosed affected child are referred for genetic counselling. It would be correct to tell them that:

TLS Online TPP Program

#Question id: 12491

#Unit 8. Inheritance Biology

Phenylketonuria shows autosomal recessive inheritance with an incidence of 1 in 10000. Assume that the population is in Hardy-Weinberg equilibrium. Which of the following is correct?

TLS Online TPP Program

#Question id: 12492

#Unit 8. Inheritance Biology

A young man with phenylketonuria, who was successfully treated following diagnosis on newborn screening, is planning to start a family with his healthy, unaffected, and unrelated partner, who has no family history of phenylketonuria . Phenylketonuria shows autosomal recessive inheritance with an incidence of 1 in 10 000. Assume that the population is in Hardy-Weinberg equilibrium. Which of the following is correct?

TLS Online TPP Program

#Question id: 12493

#Unit 8. Inheritance Biology

Cystic fibrosis shows autosomal recessive inheritance with an incidence of 1 in 2500. The unaffected brother of an affected girl is referred for genetic counseling. Assume that the population is in Hardy-Weinberg equilibrium. Which of the following is correct?