nucleotides and DNA

Question 1

what type of acids are DNA and RNA?

Answer 1

Nucleic acids

Question 2

what does DNA and RNA stand for?

Answer 2

• DNA stands for deoxyribose nucleic acid
• RNA stands for ribonucleic acid

Question 3

What does it mean by the fact that DNA and RNA are universal?

Answer 3

they are found in every cell

Question 4

What is DNA made out of

Answer 4

2 polynucleotides bonded together

Question 5

what is a nucleotide made out of?

Answer 5

• A phosphate
• A base
• A sugar

Question 6

what are the names of the different bases?

Answer 6

• Adenine
• Thymine
• Cytosine
• Guanine
• uracil

Question 7

what are the two base type categories and which bases fit into which?

Answer 7

• A base can be a purine: has 2 rings and is larger eg. A and G
• or it can be pyrimidine: has 1 ring and is smaller eg. C,U and T

Question 8

What bonds nucleotides together?

Answer 8

Phosphodiester bonds

Question 9

what type of bonds hold polynucleotide chain together to form a double helix ?

Answer 9

weak hydrogen bonds

Question 10

what does it mean if a nucleotide is the phosphorylated ?

Answer 10

it has more than 1 phosphate group

Question 11

what sugar is RNA and DNA made of?

Answer 11

• DNA: deoxyribose
• RNA: ribose

Question 12

what are the complimentary base pairs?

Answer 12

• A and T or A and U
• C and G

Question 13

describe the 6 stages of semiconservative DNA replication:

Answer 13

1. The double helix untwisted by gyrase
2. The helix is now a ladder structure.
3. Helicase break the hydrogen bonds that hold the polynucleotides together.
4. New complementary nucleotides attached onto the sugars.
5. Phosphodiester bonds form using DNA polymerise
6. You are now left with 2 pieces of DNA that then individually re-twist into double helixes

Question 14

which way do the polymer strands run in the DNA structure:

Answer 14

• the strands run opposite ways to each other in the double helix

Question 15

State five differences between RNA and DNA:

Answer 15

• RNA is made of ribose sugar, whereas DNA is made of deoxy ribose sugar
• RNA has a U base instead of a T base
• DNA has double strands, where as RNA only has a single strand
• RNA is shorter
• there are three types of RNA and only one type of DNA

Question 16

why must a purine always be paired to a pyrimidine ?

Answer 16

so the helix can roughly be the same width, and the backbone as parallel

Question 17

what do the side and middle of the double helix form/ are made of?

Answer 17

• the sides are formed by a sugar phosphate backbone
• the rugs/ middle is formed by complementary base sequences

Question 18

how are polynucleotide chains formed and joined?

Answer 18

• polynucleotide chains are joined by hydrogen bonds
• polynucleotides are formed by condensation reactions