3.4.2 DNA and Protein Synthesis

Question 1

What is RNA comprised of?

Answer 1

Phosphate group
Ribose
Nitrogenous base

Question 2

Differences between RNA and DNA?

Answer 2

DNA is ATGC; RNA is AUGC
DNA is double stranded with complementary base pairs; RNA is single stranded with no hydrogen bonds
DNA includes deoxyribose; RNA is ribose
DNA is long; RNA is shorter

Question 3

Similarities between DNA and RNA?

Answer 3

Sugar-phosphate backbone with phosphodiester bonds

Question 4

Describe mRNA?

Answer 4

Single stranded and linear
No attachment point for amino acids
No anticodons
Unstable 
Short

Question 5

Describe tRNA?

Answer 5

Clover leaf shape with areas of double stranded RNA
Has attachment points for amino acids
Three bases form an anticodon
Short

Question 6

What is transcription?

Answer 6

First stage of protein synthesis
Base sequences on a particular gene are copied onto molecule of RNA
Takes place in the nucleus

Question 7

What is splicing?

Answer 7

Exons are joined together

Introns are removed from pre-mRNA

Question 8

What happens to introns after splicing?

Answer 8

Broken down

Bases reused

Question 9

Describe the stages of transcription?

Answer 9

DNA helicase unzips the DNA that forms the gene to expose bases
Free RNA nucleotides align next to their complementary bases, joining by hydrogen bonds
RNA polymerase moves along the strand to form the sugar-phosphate backbone with phosphodiester bonds
The pre-mRNA strand is processed to remove introns and exons are spliced together
The mRNA strand leaves the nucleus through the nuclear pore

Question 10

What is translation?

Answer 10

The process in which the information from mRNA is used to direct the synthesis of a polypeptide

Question 11

Describe the stages of translation?

Answer 11

One ribosome can take two tRNA at a time and form a peptide bond between the two amino acids.
The ribosome moves along the mRNA strand.
The next tRNA is carried in, bringing the next corresponding amino acid to the mRNA.
The first tRNA is released as it
detaches from the transplant strand.
This continues until a stop codon is reached.
Th ribosome detaches from the mRNA.

Question 12

What is start code for translation?

Answer 12

AUG

Question 13

Which tRNA is always first after the start code is initiated?

Answer 13

Met

Question 14

What is needed for peptide bonds to form between amino acids in translation?

Answer 14

Energy from ATP

Question 15

How many ribosomes can travel along an mRNA strand at one time?

Answer 15

50

Question 16

What is formed by translation?

Answer 16

Polypeptide chains