Mod 5: Critical Q2

Question 1

Why is a zygote?

Answer 1

A fertiliser egg -> Replicates itself during mitosis

Question 2

Why do cells replicate?

Answer 2

• Growth & development
• Maintenance & repair

Question 3

How does cell replication assist in growth & development?

Answer 3

• New cells grow in size, which increase size of organism
• Individuals develop -> Cells become specialised
• More replications -> Specialised cells become organised into tissues -> Form organism’s body

Question 4

How does cell replication assist in maintenance & repair?

Answer 4

• Maintaining and repairing damaged tissues requires production of identical new cells to replace dead cells
• New cells produced by mitosis

Question 5

What is DNA?

Answer 5

Nucleic acid responsible for storing genetic info in cells
Contains info for growth, survival & replication

Question 6

What is the structure of DNA?

Answer 6

• 2 chains twist around to form double helix structure
• Building blocks called nucleotides
• Guanine-Cytosine, Adenine-THYMINE

Question 7

What is RNA?

Answer 7

Type of nucleic acid responsible for interpreting genetic info into proteins

Question 8

What is the structure of RNA?

Answer 8

• Nucleotides -> Contain sugar, phosphate and nitrogenous group
• Specific type of nucleotide called ribonucleotide
• Guanine-Cytosine, Adenine-URACIL

Question 9

What are the 3 steps of DNA replication?

Answer 9

1. Unravelling the DNA
2. Building a new DNA strand
3. Forming the DNA backbone

Question 10

What occurs during unravelling the DNA?

Answer 10

Enzyme helicase breaks hydrogen bonds between bases, ‘unzipping’ the double helix into two single strands

Question 11

What occurs during building the new DNA strand?

Answer 11

DNA polymerase helps bind free nucleotide in cell nucleus to the single strand

Question 12

What does semi-conservative mean?

Answer 12

When DNA is produced, one of the strands in each new DNA molecule comes from old DNA molecule

Question 13

What occurs during forming the DNA backbone?

Answer 13

• DNA polymerase stitches newly joined nucleotides together -> Sugar-phosphate backbone is formed
• Enzymes catalysts condensation reaction between adjacent phosphate + sugar
• Two identical DNA strands are formed, wound into double helix

Question 14

What is a leading strand of DNA?

Answer 14

Moves in 5’ to 3’ direction towards fork. Adds bases continuously one by one

Question 15

What is a lagging strand of DNA

Answer 15

Moves in 3’ to 5’ direction. Sections of DNA are added in okazaki fragments

Question 16

What is cell replication?

Answer 16

Process -> Cells replicate genetic material and divide to form new cells