Nucleic Acids

Question 1

What does DNA stand for?

Answer 1

Deoxyribonucleic acid

Question 2

What is the function of DNA?

Answer 2

Holds/stores genetic info
Codes for primary structure protein

Question 3

Where in eukaryotes is DNA found?

Answer 3

Mainly the nucleus
Also in chloroplasts & mitochondria

Question 4

What makes up a DNA nucleotide?

Answer 4

Deoxyribose sugar, a phosphate, a nitrogenous base (adenine, thymine, guanine or cytosine)

Question 5

What is the structure of DNA?

Answer 5

Double helix with 2 polynucleotide chains, held by hydrogen bonds between complementary base pairs
Strong phosphodiester bonds nucleotides together
Sugar phosphate backbone

Question 6

How is the structure of DNA related to its function?

Answer 6

Strong covalent bonds make stable backbone
Double stranded so replication can use one strand as a template
Weak hydrogen bonds for easy unzipping in replication
Large so carries lots of info
Complementary base pairing so identical copies can be made
Strands run antiparallel

Question 7

What does RNA stand for?

Answer 7

Ribonucleic acid

Question 8

What is the function of RNA?

Answer 8

Transfers genetic code in DNA out of nucleus to ribosomes in cytoplasm

Question 9

What are the 3 types of RNA?

Answer 9

Messenger (mRNA)
Transfer (tRNA)
Ribosomal (rRNA)

Question 10

What are ribosomes formed from?

Answer 10

RNA & proteins
Used for translation

Question 11

What makes up an RNA nucleotide?

Answer 11

Ribose sugar, a phosphate, a nitrogenous base (adenine, uracil, guanine or cytosine)

Question 12

Which nitrogenous bases are complementary

Answer 12

A-T forms 2 hydrogen bonds (U in RNA)
C-G forms 3 hydrogen bonds

Question 13

What is the structure of RNA?

Answer 13

Relatively short chain of RNA nucleotides
Single stranded

Question 14

What is mRNA?

Answer 14

A copy of a gene from DNA

Question 15

What is the function of mRNA

Answer 15

Created in the nucleus, leaves to carry copy of the gene to a ribosome in cytoplasm

Question 16

How is the structure of mRNA related to its function?

Answer 16

Much shorter (length of a gene) so leaves nucleus without damage by enzymes
Short lived (only needed to create a protein) so can be broken down after doing its job
Every 3 bases codes for a specific amino acid (codon)

Question 17

Where is tRNA found?

Answer 17

Cytoplasm only

Question 18

What is the structure of tRNA?

Answer 18

Single stranded, folds into clover shape, held by hydrogen bonds
Has anticodon on one end and amino acid attachment site on other

Question 19

What is the function of tRNA?

Answer 19

Attached 1 of 20 amino acids to ribosome. Specific amino acids attach to specific tRNA, determined by the 3 bases making up the anticodon which is complementary to mRNA’s codon

Question 20

What is the function of rRNA?

Answer 20

Makes up bulk of ribosomes

Question 21

What is the semi-conservative model of DNA replication?

Answer 21

Daughter DNA is made of 1 strand of parental DNA and 1 newly synthesised complementary strand.
One original strand is conserved

Question 22

Why does DNA replicate?

Answer 22

So each of the 2 daughter cells inherits a full set of DNA

Question 23

What are the 3 steps of DNA replication?

Answer 23

1) DNA helicase binds to DNA, breaks H bonds between complementary base pairs, separates strands, unwinds double helix
2) Each parental strand acts as template, free floating nucleotides form H bonds with complementary bases on parent DNA strands
3) DNA polymerase forms phosphodiester bonds between adjacent nucleotides by condensation, 2 new strands synthesised

Question 24

What was Watson & Crick’s research?

Answer 24

1953, discovered DNA structure, helped by Rosalind Franklin’s X-ray diffraction research
Specific base pairing involved in copying genetic info

Question 25

What was Watson & Crick’s research?

Answer 25

1953, discovered DNA structure, helped by Rosalind Franklin’s X-ray diffraction research
Specific base pairing involved in copying genetic info