NUCLEIC ACIDS AND PROTEINS

Question 1

How do nucleotides going together?

Answer 1

• process called condensation polymerisation
• the bond is created through condensation reaction between hydroxyl group at the 3rd carbon and hydrogen at 5th carbon with phosphate hear

Question 2

What is the Covalent bond between nucleotides known as?

Answer 2

phosphodiester bond

Question 3

Describe the process of transcription

Answer 3

1. RNA polymerase attached to specific promoter region of DNA at upstream region. DNA unwinds exposing bases
2. the base sequence of DNA template guides the building of a complimentary copy of DNA template in 3’-5’ direction adding bases that going to form RNA chain
3. once RNA polymerase moves past the coding region into downstream region of gene transcription stops

Question 4

Describe the process of post transcription modification

Answer 4

• Capping; the 5’ end is capped with altered guanine base, which pre-mRNA from enzyme attack and increase stability
• Poly A tail; is aded to 3’ end with up to 250 A’s. contributes to stability
• Splicing; regions that correspond to introns are cut out and remaining axons are spliced together. done by spliceosomes

Question 5

Describe the process of translation

Answer 5

1. mRNA moves to cytoplasm where it attaches to ribosomes
2. ribosome moves along mRNA molecule reading the sequence in triplets known as codons (AUG) start
3. tRNA carry anticodons on one end and a specific amino acid on the other, when complimentary anticodon pairs with codon of mRNA the amino acid are joined to start a chain
4. stops translating when either there of these codons are read (UAA,UAG,UGA)

Question 6

What is tRNA?

Answer 6

transfer RNA is a carrier molecule which consists of 76 nucleotides coiled and paired with themselves. on one end is a anticodon and on the other end is the amino acids that the anticodon codes for

Question 7

What does the process of alternative splicing of pre-mRNA suggest?

Answer 7

• one gene can produce different proteins at different stages of life
• one gene can produce different proteins in different tissues

Question 8

How does pre-mRNA splicing work?

Answer 8

• can occur post transcription modification of pre-mRNA

- usually involves exon juggling where different combinations of axons are spliced together

Question 9

Define proteome

Answer 9

is the complete array of proteins produced by a single cell or organism in a particular environment

Question 10

What are the functions of protein ?

Answer 10

Transport
Enzymes
Anti-bodies
Contractile proteins
Hormones
Exported proteins
Receptors
Structural proteins