Biology Answers

1. Explain the features of the molecule represented in the structural diagram below. You must identify and describe each of the following:
2. Type of macromolecule and how you know
3. Functional groups present

In this hypothetical population, the deleterious recessive allele exists at a proportion of 0.01. In an offspring with randomly chosen parents, what is the probability that the offspring will be homozygous for the deleterious recessive allele [q]?

The following pedigree analysis shows the inheritance of a recessive trait.

a. If individuals III-3 and III-8 marry, what is the probability of them having a child who phenotypically expresses the trait?

b. If individuals IV-1 and IV-10 marry, what is the probability of them having a child who phenotypically expresses the trait?

Q1. The following diagrams represent cells from a diploid organism with (2n=4) undergoing different stages of a division designated as (I,II, III,IV): 

a.      for each of the divisions, describe and conclude the type of division and its specific stage. (1.5 Marks each)

Describe the process of ‘crossing over’ detailing at what stage of the cell cycle it occurs. What effect does crossing-over process have on linked genes with respect to the relative distance on the chromosome? How can we calculate the distance of two linked genes?

What carries air to and from lungs?

Preserved bodies of cave dwelling man from cold and icy places suggested that humans look different in the past, what evidence of evolution is used?

Draw two diagrams and label them indicating eukaryotic DNA replication and theta replication in E. coli. Highlight the similarities and differences. 

One type of conditional mutation is a temperature-sensitive mutation, which expresses the mutant phenotype only at certain temperatures. Strains of E. coli have been isolated that contain temperature-sensitive mutations in the genes encoding different components of the replication machinery. In each of these strains, the protein produced by the mutated gene is non-functional under the restrictive conditions. These strains are grown under permissive conditions and then abruptly switched to the restrictive condition. After one round of replication under the restrictive condition, the DNA from each strain is isolated and analysed. What characteristics would you expect to see in the DNA isolated from each strain with a temperature sensitive mutation in its gene that encodes a) DNA polymerase III, b) primase and c) initiator protein?

For centuries, people have searched for the fabled Fountain of Youth, said to confer the ability to

forestall old age and remain young forever. To gain insight into how tackling aging by targeting

telomerase might work, researchers looked at mice that lack a telomerase gene. These mice have

shorter telomeres than normal mice and age prematurely. However, when these mice were engineered

to express telomerase in their somatic cells, their telomeres lengthen and the effects of aging are

reversed. This observation suggests that a drug that stimulates the expression of telomerase in somatic

cells could prevent telomere shortening and stop the aging process. Consider how such a drug would

work and what may be some potential side effects of such a drug?