Nucleic Acids and DNA 🧬

Question 1

What are introns?

Answer 1

Non-coding regions of DNA that play a large part in regulating gene expression, usually contains sequence that repeats.

Spliced out of the RNA during protein synthesis.

Not contained in prokaryote

Question 2

What are exons?

Answer 2

The coding regions.

Question 3

What does it mean by DNA being degenerate?

Answer 3

Multiple codons can code for same amino acid

Question 4

What does the term universal suggest about DNA?

Answer 4

Triplet code is source/same for every organism.

Question 5

What is the role of DNA?

Answer 5

Contains genetic information which code to make proteins.

Question 6

What nitrogenous bases are pyrimidines?

Answer 6

Pyrimidines——-> 1 carbon ring structure

Thymine

Uracil

Cytosine

Question 7

What nitrogenous bases are purines?

Answer 7

Purines——–> 2 carbon ring structures.

Adenine

Guanine

Question 8

What is meant by the term ‘anti-parallel’?

Answer 8

DNA always read from the 5’ to 3’ strand direction.

DNA polymerase = only bind to 3’ strand.

Work in only one direction.

Antisense strand runs from 3’ to 5’ ——-> makes a mRNA strand which has same base sequence of the sense strand which codes for correct amino acid.

Question 9

What is the semi conservative module?

Answer 9

Idea that OG strand of DNA acts as a template for the synthesis of the new strand of DNA.

One parent strand and one new daughter strand of DNA.

Question 10

How did research into DNA being semi conservative come about?

Answer 10

OG DNA = N-14.

~~~would be lighter in the centrifuge.

Free DNA nucleotides =N-15
~~~~ would sink in centrifuge

Centrifuge——>separate substances based on their densities.

Question 11

What were the results?

Answer 11

Parent strand =All N-14

First generation = N-14/N-15 mix

Second generation = Half N-14/N-15 and other half =N-15

Question 12

What is DNA replication?

Answer 12

Before cell divides DNA must be copied to ensure all cells have same genetic information.

Question 13

How is DNA replicated?

Answer 13

DNA gyrase —->unwinds DNA.

DNA helicase breaks hydrogen bonds between the polynucleotide strands.

Each strand acts as template.

Free-floating DNA nucleotides join to exposed bases on each OG strand ~~~~ complementary base pairing.

Nucleotides joined together by DNA polymerase.

Hydrogen bonds form between bases of OG strand and new strand.

Formation of double helix.

Question 14

What is the role of DNA polymerase?

Answer 14

Catalyses formation of sugar phosphate backbone.

Question 15

What is transcription?

Answer 15

First stage of protein synthesis.

mRNA strand made in nucleus to leave nuclear pore.

Question 16

Process of transcription.

Answer 16

H bonds broken between complementary base pairs

Free RNA nucleotides pair with the exposed bases.

Uracil base pairs with Adenine.

RNA polymerase joins with RNA nucleotide forming a phosphodiester bonds —–> mRNA made.

mRNA leaves nuclear pore ~~~ goes to ribosome for translation.

Question 17

What are codons?

Answer 17

A sequence of 3 bases that code for one amino acid.

Question 18

What are anticodons?

Answer 18

Sequence of 3 bases on tRNA that is complementary to a specific codon on mRNA.

Question 19

Process of translation.

Answer 19

mRNA binds to ribosome at the start codon.

tRNA with complementary anticodon binds to mRNA start codon.

tRNA will carry an amino acid corresponding that codon.

Amino acids form peptide bonds between one another.

Ribosomes act as a binding site for mRNA and tRNA and catalyse assembly of the protein via enzyme peptidyl transferase.

Question 20

What is ATP?

Answer 20

Used for energy transfer of all living things.

Known as ——–> universal energy currency.