BY5.1 - The Genetic Code and Cell Function

Question 1

During what phase of mitosis does replication occur?

Answer 1

Interphase

Question 2

Explain the process of DNA replication

Answer 2

• DNA unwinds and the hydrogen bonds holding the two strands of DNA together break; this is sometimes referred to as unzipping
• The enzymes DNA polymerase catalyses the addition of free DNA nucleotides to form two new complementary strands using the original as a template
• Hydrogen bonds then form between each pair of complementary DNA strands (one original and one new). This produces two molecules of DNA that are identical to each other and the original DNA

Question 3

What is the name of the process by which DNA copies?

Answer 3

DNA replication

Question 4

What are the three theories of DNA replication?

Answer 4

Conservative
Semi-conservative
Dispersive

Question 5

What is meant by ‘semi-conservative’ replication?

Answer 5

Each new DNA molecule contains one original strand and one newly formed strand

Question 6

What’s the difference between meiosis and mitosis?

Answer 6

Mitosis is a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent cell

Meiosis is a form of cell division that is used to produce gametes. This results in the production of 4 haploid cells that are genetically different (contain different chromosomes) to the parent cell

Question 7

What is the purpose of ‘transcription’ during protein synthesis?

Answer 7

Transcribe the code for the polypeptide from DNA to mRNA so that it can be transported to the ribosome

Question 8

What is the mRNA code used for during ‘translation’?

Answer 8

Formation of the polypeptide

Question 9

Where does translation occur?

Answer 9

At the ribosome

Question 10

Where does transcription occur?

Answer 10

In the nucleus

Question 11

What is formed from DNA during transcription?

Answer 11

A complementary mRNA strand

Question 12

Explain the process of transcription

Answer 12

• A section of DNA unwinds and the hydrogen bonds holding the two strands break (DNA unzips)
• The enzyme RNA polymerase catalyses the addition of free RNA nucleotides to form a complementary strand of messenger RNA (mRNA)
• Translation can then occur

Question 13

What are the complementary DNA pairs?

Answer 13

Adenine - Thymine

Guanine - Cytosine

Question 14

What are the complementary bases that form between DNA and mRNA?

Answer 14

Cytosine on the DNA - guanine on the mRNA
Guanine on the DNA - cytosine on the mRNA
Thymine on the DNA - Adenine on the mRNA
Adenine on the DNA - Uracil on the mRNA

Question 15

What is the role of tRNA?

Answer 15

tRNA is used to transfer amino acids to the ribosome

Question 16

True or false

The daughter cells produced from meiosis are genetically similar to the parent cell

Answer 16

False - all of the 4 daughter cells are genetically different to each other and to the parent cell

Question 17

Define haploid

Answer 17

The daughter cells have half the number of chromosomes than the parent cells

Question 18

What are the phases of mitosis?

Answer 18

Interphase, prophase, metaphase, anaphase, telophase

In pairs mums are talkative

Question 19

During what phase of meiosis does ‘independent assortment’ occur?

Answer 19

Metaphase I

Question 20

What is the sequence of DNA bases that this mRNA strand was formed from?

UGCGAUAG

Answer 20

ACGCTATG