Nucleic Acids + Nucleotides

Question 1

Which 5 elements are found in nucleic acids?

Answer 1

C,H,N,O,P

Question 2

What are the three main components of nucleotides?

Answer 2

Pentose Sugar, Nitrogenous base, Phosphate

Question 3

State the 4 bases in DNA

Answer 3

Adenine
Guamine
Thymine
Cytosine

Question 4

Which 2 bases are purines?

Answer 4

Adenine, Guamine

Question 5

What is the difference between purines and pyrimidines?

Answer 5

Purines have 2 carbon-nitrogen rings

Question 6

Which pentose sugar does DNA contain?

Answer 6

Deoxyribose

Question 7

Which base is replaced by uracil in RNA?

Answer 7

Thymine

Question 8

Is the base uracil a purine or pyrimidine?

Answer 8

Pyrimidines

Question 9

State 2 phosphorylated nucleotides

Answer 9

ADP, ATP

Question 10

What two reactants form ATP?

Answer 10

ADP and an inorganic phosphate

Question 11

Is energy released or stored within a phosphate bond?

Answer 11

Energy is STORED in bonds

Question 12

What type of reactions do polynucleotides form in?

Answer 12

Condensation

Question 13

What type of bond joins pentose sugar and a phosphate group?

Answer 13

Phosphodiester bond

Question 14

How many hydrogen bonds form between adenine and thymine?

Answer 14

2 H bonds

Question 16

Which bases form 3 hydrogen bonds in DNA?

Answer 16

Cytosine and Guamine

Question 17

What is the role of DNA helicase?

Answer 17

To break H bonds, unzip double helix

Question 18

Describe the process of self replication of DNA

Answer 18

• DNA helicase unzips double helix
• Free floating DNA nucleotides join to template strands
• Nucleotides joined by DNA polymerase
• H bonds reform

Question 19

Explain the term ‘semi conservative replication’

Answer 19

One strand on each new DNA molecule is from the original DNA molecule

Question 20

Define ‘mutation’

Answer 20

A random change to DNA base sequence

Question 21

What is a gene?

Answer 21

A sequence of DNA nucleotides that code for a polypeptide

Question 22

What is the primary structure of a protein?

Answer 22

The sequence of amino acids in a polypeptide

Question 23

What is a codon?

Answer 23

Three bases

Question 24

What codes for an amino acid?

Answer 24

A codon

Question 25

Why is RNA used during protein synthesis instead of DNA?

Answer 25

As DNA is too big to fit through nuclear pores

Question 27

What are the 3 types of RNA?

Answer 27

mRNA, tRNA, rRNA

Question 28

What is rRNA used for?

Answer 28

Catalysing the formation of peptide bonds

Question 29

What is the function of tRNA?

Answer 29

To carry amino acids to ribosomes for translation

Question 30

Where are tRNA molecules found?

Answer 30

Cytoplasm

Question 31

What are the 2 stages of protein synthesis?

Answer 31

Transcription + Translation

Question 32

What is the function of RNA polymerase?

Answer 32

To assemble mRNA strand

Question 34

Describe the first stage of transcription

Answer 34

- RNA polymerase attaches to DNA double-helix - H bonds between strands break causing DNA to unwind

Question 35

What happens, in transcription, after DNA unwinds?

Answer 35

Free RNA nucleotides are lined up (complementary bases to mRNA)

Question 36

What happens, during transcription, when RNA polymerase reaches a stop codon?

Answer 36

It detaches from DNA molecule

Question 38

What is the first stages of translation?

Answer 38

mRNA attaches to ribosome

Question 39

What do tRNA carry which enables translation of polypeptide?

Answer 39

Complementary anticodon

Question 40

What catalyses formation of peptide bonds between 2 amino acids, during translation?

Answer 40

rRNA

Question 41

What stops translation of a polypeptide?

Answer 41

Stop codon