B1.2

Question 1

State the role of DNA in the body

Answer 1

DNA is a biological polymer made from nucleotide monomers

DNA is the substance that contains all the instructions that determine your characteristics

Question 2

Where is DNA found

Answer 2

In the nucleus

Question 3

Each long molecule is a ….

Answer 3

… Chromosome

Question 4

What is a chromosome

Answer 4

Long molecule of tightly coiled DNA

Question 5

How many pairs or chromosomes do humans have

Answer 5

23 (46 chromosomes)

Question 6

What is a gene

Answer 6

A short section of DNA found upon a chromosome which codes for a specific protein

Question 7

Order it

Answer 7

Nucleotide (smallest)
Gene
DNA
Chromosome
Genome
Nucleus
Cell (largest)

Question 8

What are nucleotides?

Answer 8

The building blocks of DNA
Small units that make up up dna

Question 9

What does a nucleotide consist of?

Answer 9

1. Phosphate backbone
2. Deoxyribose sugar
3. Base.

Question 10

What is the structure of DNA

Answer 10

Double helix (2 strands joined together by bases)

Question 11

What are the bases and their complimentary pairing?

Answer 11

A -> T
C -> G

Question 12

What is a polymer

Answer 12

polymers are large molecules (like DNA) made by bonding a series of building blocks

Question 13

What is the name of the weak bonds formed between bases of opposing strands of DNA?

Answer 13

Hydrogen bonds

Question 14

Name the 2 main stages of protein synthesis

Answer 14

Transcription (1) and translation (2)

Question 15

What is mRNA

Answer 15

mRNA is a singular strand of DNA that contains bases and carries those into the cytoplasm

Question 16

What is transcription

Answer 16

Transcription is when the 2 strands of DNA unzips and one strand is used as a template for mRNA to use and the complimentary bases are copied onto the mRNA. And as DNA is too large to send out the nucleus. mRNA travels out of the nucleus into the cytoplasm.

Question 17

What are proteins made from.

Answer 17

Amino acid chains

Question 18

That is translation

Answer 18

Translation is when the mRNA attaches to the ribosome and the ribosome reads the nucleotides in groups of threes called codons then tRNA attaches the anticodon (the complimentary base pairings to the mRNA) to the amino acid. A chain of amino acids are formed. A protein is formed

Question 19

What is rna

Answer 19

A singular strand of dna

Question 20

What are enzymes

Answer 20

Enzymes are biological catalysts - they speed up a reaction without being used up. They are made out of proteins

Question 21

What are example of what enzymes do?

Answer 21

• build larger molecules from small ones, such as in protein synthesis
• break down large molecules into smaller ones, such as in digestion.

Question 22

What is the name of the molecule the enzyme binds to?

Answer 22

Substrate

Question 23

What is an active site?

Answer 23

The area of the enzyme that attaches to the molecule it is trying to break down

Question 24

What happens when an enzyme is trying to break down a substrate?

Answer 24

The substrate (which has a specific shape) binds to the active site (has a specific shape) which is part of the enzyme. The substrate fits inside the enzyme to form an enzyme-substrate complex

Question 25

What is formed when a substrate binds to an enzyme

Answer 25

An enzyme-substrate complex

Question 26

Can enzymes bind to any substrate?

Answer 26

No, enzymes are highly specific. They can only bind to one type of enzyme molecule. (Lock and key)

Question 27

What happens in the reaction where enzymes build larger molecules from smaller ones?

Answer 27

1. The substrate molecules fit into the enzymes active site
2. The bond forms
3. Product is released
4. Enzyme is ready to catalyse another reaction

Question 28

What happens in the reaction where enzymes breakdown large molecules into smaller ones?

Answer 28

1. The large Substrate molecule fits into the active site
2. The bond breaks
3. The 2 smaller products are released
4. Enzyme ready to catalyse another substrate

Question 29

What factors affect enzyme activity?

Answer 29

1. Temperature
2. pH
3. Enzyme and substrate concentration

Question 30

How does the temperature affect the reaction?

Answer 30

• the higher the temperature, the faster the reaction
• the optimum temperature(the highest before denaturing) is when it works best
• if the temperature gets too high, the enzyme will denature meaning the amino acids chains will unravel changing the shape of the active site.
  - the substrate can no longer bind to the active site so the rate of reaction decreases. Once all enzyme molecules are denatured the reaction stops

Question 31

How does pH affect the reaction?

Answer 31

• if the pH is changed, it will affect the interactions between the amino acids in the chain
• this makes the enzyme unfold changing the shape of the active site (it has denatured)
• each enzyme has an optimum pH

Question 32

How does the concentrations of the enzyme and substrate affect the reaction?

Answer 32

• the higher the substrate concentration is, the faster the reaction
• the higher the enzyme concentration the faster the reaction
• but at a certain point the rate of reaction is at its MAXIMUM (point of saturation). All of the substrate molecules are connected to the enzyme molecules (there are none left to connect).
  - any further increase of the substrate molecules will not increase the rate of reaction because there are no enzyme molecules for them to connect to
• same with the enzymes (once all the substrate molecules are used up, the reaction will stop)