DNA & RNA Structure

Question 1

Nucleotide

Answer 1

The basic building block of nucleic acids (DNA and RNA)

-Consists of a phosphate group, nitrogenous base, sugar

Purines: double ring structure (Adenine and Guanine)

Pyrimidines: single ring structure (Cytosine, Uracil, Thymine)

The base pairs are held together by hydrogen bonds
-A & T have two hydrogen bonds
-C & G have three hydrogen bonds

Question 2

DNA (Deoxyribonucleic acid)

Answer 2

Primary source of heritable information
(genetic information is stored in and passed from one generation to the next through DNA)

Double stranded helix
-Backbone (outside): sugar-phosphate
-Center (inside): nucleotides pairing

Strands are antiparallel
-One strand runs 5’ to 3’ and other strand runs 3’ to 5’ upside direction
-5’ end: free phosphate group
-3’ end: free hydroxyl group

Codons: Cytosine, Guanine, Adenine, Thymine

Question 3

RNA (Ribonucleic acid)

Answer 3

Primary source of heritable information in some viruses

Single stranded

Codons: Uracil, Adenine, Guanine, Cytosine

Question 4

Prokaryotic DNA

Answer 4

-Found in the nucleus
-Linear chromosomes (contains terminal ends)

Question 5

Eukaryotic DNA

Answer 5

-Found in nuclei of region
-Circular chromosomes

Question 6

Plamids

Answer 6

Small, circular DNA molecules that are separate from the chromosomes

-Prokaryotes (some eukaryotes) contain plasmids
-Plasmids replicate independently from chromosomal DNA
-Contains genes that may be useful to prokaryote when it is in a particular environment, but may not be required for survival

Conjugation: Bacteria can exchange genes found on plasmids with neighboring bacteria