Biology Answers

Compare and contrast the two main theories as to how multicellular organisms arose.

1. What are two components shared by all viruses?
2. Viruses are generally considered to be non-living. Should viroid and prions also be viewed as non-living? why? [2]
3. A wart is caused by a virus that may lie dormant for years before any symptoms appear. Does this resemble a lytic or lysogenic infection? Explain [2 marks]
4. During the lysogenic cycle of a virus, what happens to the viral nucleic acid after it is injected into the host cell? [1]
5. Name four viruses that can cause diseases, that are fatal.
6. Explain the relationship between shingles and chickenpox? [2]

scientific term that describes the number of body layers of the flatworms

What is the age of the Earth? Describe using the two methods of dating.

What logic suggests that the chromosomal integration of tumor virus genomes is an
intrinsic, obligatory part of the replication cycle of RNA tumor viruses but an inadvertent
side product of DNA tumor virus replication?

A tripeptide "YES" was isolated from the hydrolyzed venom of Taal lake freshwater sea snake (Hydrophis semperi). This peptide was found to exhibit a potent pain-killing effect (analgesic effect). Draw the structure of the tripeptide, give its systenatic name, show its titrimetric profile and determine its isoelectric pH.

Glutathione is a naturally-occurring tripeptide that has potent antioxidant property. It has become a popular ingredient in various whitening pills and cosmetic products. Its systematic name is γ-glutamylcysteinylglycine tripeptide. Draw the structure of glutathione and label the N-terminal and C-terminal amino acids.

Describe the possible effects of this change on the shape of the protein and how it functions.