DNA & Genes (General) - Nishimoto

Question 1

What is DNA?

Answer 1

Linear arrangement of bases that code for genes and the genetic makeup of the body

Question 2

What is a mutation?

Answer 2

A change in the linear sequence of a gene

Question 3

Why are nucleic acids important?

Answer 3

Basis to determine techniques for mutations
Basis for understanding genetic disorders, cancer
Basis for paternity tests
Biochemical basis for human genetics

Question 4

Describe the 5’ end

Describe the 3’ end

Answer 4

5’ - -OH end with phosphate group

3’ - free -OH group

Question 5

How are double strands held together?

Answer 5

H-bonds

Question 6

Topoisomer, what can this do?

Answer 6

Supercoiled DNA. Can be bad, different energetic forms, can impede strand separation for DNA replication by DNA helices

Question 7

What induces supercoiling?

Answer 7

Pulling two strands apart (similar to replication fork)

Question 8

How is supercoiling relieved?

Answer 8

Enzymes called topoisomerases

Question 9

Topoisomerase I

Answer 9

Breaks a single strand to relieve supercoiling. 1 catalytic cycle relaxes 1 supercoil

Question 10

Topoisomerase II

Answer 10

Breaks a double strand to relieve supercoiling. 1 catalytic cycle relaxes 2 supercoils. Can also untangle DNA strands. Acts like a gate by allowing a passage by opening transiently one strand so that the other strand can pass through

Question 11

How are topoisomerases clinically important?

Answer 11

They are the targets of antimicrobial and anticancer drugs

Question 12

5 classes of RNA

Answer 12

mRNA - coding
rRNA - synthesis
tRNA - transport
snRNA (spliceosomes)
scRNA (small cytoplasmic part)

Question 13

What is structural difference between ribose and deoxyribose? RNA & DNA?

Answer 13

Ribose - OH on 2’ C

RNA - U rather DNA’s T
RNA - single stranded, but can fold on itself via H-bonds

DEOXYribose - H on 2’ C