Biology Past Questions and Answers

In the structure of DNA, which of the following statements is true?

A The double helix are held together by covalent bonds
B Nucleotide is made up of ribose, phosphate and an organic nitrogen compound
C Guanine is the opposite of cytosine
D Adenine is the opposite of cytosine

Question 1457:

In a case of complete dominance, what is the phenotypic ratio of the cross Bb X Bb; where B =black and b = white?

A 1 black : 1 grey : 2 whites
B 1 black : 3 whites
C 1 black : 2 blues : 1 white
D 3 blacks : 1 white

Question 1458:

Two yellow-flowered hybrid plants each carrying a recessive factor for flowers with green colour were crossed.
Which of the following ratios shows the correct proportion of offspring that have green flowers?

A 2 in 2
B 1 in 3
C 1 in 4
D 1 in 5

Question 1459:

What name is given to a sudden change in a gene or chromosome?

A Allele
B Genotype
C Mutation
D Phenotype

Question 1460:

Bees are of great importance to the farmer because they

A Provide him with honey
B Pollinate flowers
C Sting crop pests to death
D Destroy flowers by sucking nectar from them