Lecture 3 - DNA and Genetic Code

Question 1

What are nucleic acids?

Answer 1

Made of nucleotide subunits

Question 2

What is the function of nucleic acids?

Answer 2

Function in cell is to make proteins including RNA and DNA

Question 3

What are the three sub units that make up a nucleotide

Answer 3

Phosphate
Nucleotide
Nitrogen- Containing base

Question 4

What is the difference between DNA and RNA molecules?

Answer 4

DNA has deoxyribose as it’s sugar (just H)

RNA has ribose sugar(OH)

Question 5

What are the bases in DNA

Answer 5

Adenine (double ringed purines)
Guanine (Double ringed)
Cytosine (single ringed pyrimidines)
Thymine

Question 6

What are the bases in RNA?

Answer 6

Adenine
Guanine
Cytosine
Uracil

Question 7

How are polynucleotides formed?

Answer 7

Condensation Reaction which creates a bond between sugar and phosphate groups
this results in a phosphate “backbone”

Question 8

What are the structural differences of DNA and RNA

Answer 8

DNA is double stranded

RNA is single stranded

Question 9

What are the base pairings?

Answer 9

A and T

C and G

Question 10

Why is DNA double stranded?

Answer 10

Makes it more stable and is less easily degraded

Question 11

What is semi-conservative replication?

Answer 11

Preserves the genetic code

Question 12

What is the function of DNA polymerase?

Answer 12

Unzips the DNA structure and is a catalyst for it

Question 13

What is the purpose of DNA?

Answer 13

Store information, or code that is required to make polypeptides (proteins)

Question 14

What is the role of mRNA

Answer 14

Messenger RNA that helps translate the genetic code into the sequence of amino acids

Question 15

How does protein synthesis occur?

Answer 15

Transcription in which mRNA is created from DNA

then Translation in which mRNA is translated into a protein

Question 16

What is a codon?

Answer 16

Create 64 possible sequences

Question 17

What is the process of transcription

Answer 17

Makes mRNA.
This process is catalysed with RNA polymerase
A with U
C with G

Question 18

How does translation occur?

Answer 18

Site is at ribosome usually at RER

1. mRNA molecule binds with the ribosome
2. tRNA molecules carry amino acids to the ribosomes (two can enter at a time)
3. Bonding occurs between adjacent amino acids from the polypeptide bond
4. tRNA released into cytoplasm an will bind with another amino acid

Question 19

What is the purpose of anti-codons on tRNA molecules and codons on mRNA?

Answer 19

Order in which tRNA molecules is determined by codon sequence