B1.2 What Happens In Cells

Question 1

Describe the structure of DNA

Answer 1

• It is a polymer made up of many nucleotide monomers

- It is made of 2 strands in the shape of a double helix

Question 2

Describe the structure of a nucleotide

Answer 2

A nucleotide contains a 5 carbon sugar, phosphate group and nitrogenous base

Question 3

Name the 4 bases in DNA

Answer 3

Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)

Question 4

How does the bases in DNA pair up

Answer 4

A with T

C with G

Question 5

Describe transcription

Answer 5

• DNA unzipped
• Complementary mRNA nucleotides bind and are joined together
• mRNA detaches and leaves the nucleus

Question 6

Describe translation

Answer 6

• mRNA travels to a ribosome
• Carrier molecules carry amino acids to the ribosomes based on the mRNA sequence
• The amino acids are joined together

Question 7

How does the sequence of DNA affect the protein made in protein synthesis?

Answer 7

DNA is a triple code where 3 bases code for one amino acid and the order of amino acids determine the protein produced

Question 8

What are enzymes?

Answer 8

Enzymes are biological catalyst that speed up the rate of metabolic reactions

Question 9

Describe the structure of enzymes

Answer 9

Enzymes are proteins that contain an active site that fits a specific substrate

Question 10

Describe the lock and key hypothesis

Answer 10

A substrate that fits the specific active site of an enzyme binds, a reaction occurs (catalysed by the enzyme) and then the products are released

Question 11

State 4 factors that affect enzyme function

Answer 11

• Temperature
• pH
• Substrate concentration
• Enzyme concentration

Question 12

Describe the effect of temperature on the rate of an enzyme controlled reaction

Answer 12

As the temperature increases, so does the rate of reaction

Once the temperature exceeds the optimum, the enzyme denatures and the rate of reaction decreases