Chapter 5- DNA

Question 1

What does DNA stand for?

Answer 1

Deoxyribonucleic acid

Question 2

What is the function of RNA and DNA?

Answer 2

Form genetic material and are involved in the functioning of chromosomes and in protein synthesis

Question 3

What is the structure of DNA called?

Answer 3

Double helix

Question 4

What are nucleotides composed of? (3 key parts)

Answer 4

• Phosphoric acid
• 5 carbon sugar (deoxyribose)
• nitrogen base

Question 5

What are the 4 nitrogenous bases in DNA called?

Answer 5

Thymine, Adenine, Cytosine, Guanine

Question 6

What is the “backbone” of DNA composed of?

Answer 6

Sugar and phosphates

Question 7

Why can’t the nitrogenous bases bond any other way?

Answer 7

Because Guanine and Adenine are purines(double rings) and they’d overlap if they joined together

Question 8

How are the nitrogenous bases held together? (What type of bond?)

Answer 8

Hydrogen bonds

Question 9

What are the functions of DNA? (There are 3)

Answer 9

• replicates itself so each new cell is an identical copy
• produces proteins that control the activities of the cell, which determines the characteristics of each living organism
• undergoes occasional mutations, which is the reason for the variety of living things

Question 10

What are the steps in DNA replication?

Answer 10

• An enzyme called Helicase, breaks the weak hydrogen bonds, which results in the DNA molecule untwisting
• Polymerase, an enzyme, helps with complementary base pairing, when new nucleotides in the nucleus join with the exposed strands
• The enzyme Ligase glues the alternating sugar phosphate backbone together in a newly forming chain
• This forms two complete DNA strands
• The DNA strands will now wind up into their helical shape

Question 11

How is recombinant DNA formed?

Answer 11

By introducing foreign genes into a bacterial plasmid, which makes an new combination of DNA, using a vector

Question 12

What are the uses of recombinant DNA?

Answer 12

• To generate a DNA library, which catalogues all the base sequences of known genes
• To identify specific genes
• To produce synthetic copies of genes
• To insert genetic material into chromosomes that will help regulate cell function to better the organism genetically

Question 13

How is RNA different from DNA?

Answer 13

• Made of one strand
• Instead of Thymine, contains Uracil as a nitrogenous base
• Contains ribose as it’s sugar (DNA contains deoxyribose)