Question

1) All living organisms, including bacteria, plants, humans and other animals, are made up of one or more cells. Explain why all living organisms need to have DNA. Include the words genes and proteins in your explanation.

2)Explain how a difference in the sequence of nucleotides in a gene could result in one boy being albino and the other boy having normal skin and hair color.

3)Copy and complete this chart to describe how a person's DNA determines whether he has hemophilia. (Hint: begin by completing the bottom box in the protein column.)

Gene in DNA	Protein	Characteristic
		Normal formation of blood clots prevents excessive bleeding.
		Hemophilia (excessive bleeding because clots do not form normally because one type of clotting protein is defective)

4) Explain why a cell needs to replicate its DNA before the cell divides into two daughter cells.

Answer 1

1. All living organisms, including bacteria, plants, humans and other animals, are made up of one or more cells.All living organisms need to have DNA as a genetic material. DNA have all the genetic information in the form of genes and which is transfered from one generation to next generation.Genes have the coding information in the form of nucleotide sequence which encode the proteins. All functional genes produced the functional proteins through the process of transcription and translation.These functional proteins are important for the cellular activity such as metabolism, cell division, proliferation, differentiation and reproduction of organism.

2. Albino boy having the mutaion in the enzyme (TRP-1) of melanin synthesis pathway. There is a mutations in the nucleotide sequence of tyrosinase enzyme which is important for the synthesis of melanin from tyrosine. and normal boy have functional tyrosinase enzyme which produced melanin pigment from tyrosine

3.

Gene in DNA	Protein	Characteristic
F8 gene	Coagulation factor VIII	Normal formation of blood clots prevents excessive bleeding.
Defective F8 Gene	Non-functional Coagulation factor VIII	Hemophilia (excessive bleeding because clots do not form normally because one type of clotting protein is defective)

4.Cells need two replicate the DNA before divided into two daughter cells to make the identical or same DNA copy . DNA replication produced the similar copies of DNA which is equally distributed during the cell division in each daughter cells .New daughter cells replaced the old and damaged cells which having similar or equal no. of DNA as a parent cells.