Gene Expression Unit 1

Question 1

Describe 3 differences between DNA and RNA

Answer 1

• DNA is double stranded and RNA is single stranded
• Deoxyribose sugar is the nucleotide present in DNA and Ribose sugar is the nucleotide present in RNA
• The base partner for Adenine is Thymine in DNA and Uracil in RNA

Question 2

Name the two stages involved in Gene Expression

Answer 2

Transcription and Translation

Question 3

In which region of the cell does transcription take place ?

Answer 3

In the nucleus

Question 4

Name the region on the DNA strand where transcription begins

Answer 4

Promoter region

Question 5

Name the enzyme involved in transcription

Answer 5

RNA polymerase

Question 6

Name the region on the DNA strand where transcription end

Answer 6

Terminator

Question 7

What name is given to the strand formed initially after transcription ?

Answer 7

Primary transcript of mRNA

Question 8

What process follows the formation of the primary transcript of mRNA ?

Answer 8

Splicing

Question 9

Where does the process of splicing occur ?

Answer 9

In the nucleus

Question 10

During splicing, what parts are cut out ?

Answer 10

Non coding regions called introns

Question 11

During splicing, what regions are retained ?

Answer 11

Coding regions called exons

Question 12

The same piece of DNA can be used to make several proteins due to the facts that on occasions different regions can act as introns and exons, what name is given to this ?

Answer 12

Alternative RNA splicing

Question 13

In which part of the cell does translation occur ?

Answer 13

Ribosome

Question 14

Where are tRNA molecules found ?

Answer 14

In the cytoplasm

Question 15

What name is given to every 3 bases on mRNA ?

Answer 15

A codon

Question 16

What name is given to the three bases at one end of a tRNA molecule ?

Answer 16

An anticodon

Question 17

The anticodon acts as a codeword to attach something to the other end of the tRNA, what is it that attaches ?

Answer 17

An amino acid

Question 18

How many different amino acids exist ?

Answer 18

20

Question 19

A mRNA strand attaches at a ribosome binding site, where does the process of translation begin ?

Answer 19

Start codon

Question 20

What type of bonds form between codons and anticodons as they pair up ?

Answer 20

Hydrogen bonds

Question 21

Amino acids start to align with one another when tRNA anticodons join up with mRNA codons, what type of bond forms between adjacent amino acids ?

Answer 21

Mainly peptide bonds

Question 22

When does the process of translation stop ?

Answer 22

When a stop codon is reached

Question 23

What happens to the tRNA and mRNA at the end of translation ?

Answer 23

It detaches from the ribosome and is released back into the cytoplasm for reuse

Question 24

What other type of bond can be found between a polypeptide a paper from peptide bonds ?

Answer 24

Hydrogen bonds

Question 25

Name some functions of the proteins produced in gene expression ?

Answer 25

- Enzymes - Hormones - Antibodies - Structural proteins

Question 26

What combination of factors determine the overall phenotype of an individual ?

Answer 26

Genotype and environmental factors

Question 27

How is a cells genotype determined ?

Answer 27

By the sequence of the DNA bases in its genetic code

Question 28

How is a cells phenotype determined ?

Answer 28

By the proteins that are synthesised when the genes are exposed

Question 29

Where does the information get copied and transported to ?

Answer 29

The ribosome

Question 30

The copying and transport of the DNA code requires a second molecule of what ?

Answer 30

mRNA

Question 31

What does the code copied from DNA have to be read by ?

Answer 31

A special ‘protein building’ machine called a ribosome

Question 32

A ribosome is built from what ?

Answer 32

A second type of RNA called rRNA

Question 33

The assembly of proteins requires amino acids to be called into position. This requires what ?

Answer 33

A third type of RNA called tRNA

Question 34

What is translation ?

Answer 34

The assembly of proteins requiring amino acids to be called into position. This requires a third type of RNA called tRNA

Question 35

What is transcription?

Answer 35

Transcription is the synthesis of mRNA from a section of DNA

Question 36

What does mRNA do ?

Answer 36

It copies a section of the DNA and carries it into the cytoplasm to a ‘protein building’ called a ribosome

Question 37

What does tRNA do ?

Answer 37

It carries the amino acids into position at the ribosome. This process is called translation

Question 38

What is rRNA ?

Answer 38

The RNA part of a ribosome which aids protein synthesis

Question 39

What is RNA Polymerase responsible for ?

Answer 39

This enzyme is responsible for transcription at it moves along the gene, unwinding and opening the DNA strand

Question 40

What does RNA polymerase form ?

Answer 40

The mRNA strand by joining nucleotides together

Question 41

What end can nucleotides join onto ?

Answer 41

The 3’ end of the mRNA strand

Question 42

What is splicing ?

Answer 42

These are long sections of DNA that do not code for a polypeptide. These are called introns