3.1.5/6 DNA + RNA/ ATP

Question 1

What is DNA?

Answer 1

Codes for the sequence of amino acids in the primary structure of a protein, which determines the final 3D structure and function of a protein
DNA is a polymer and is a double helix

Question 2

Why is DNA important?

Answer 2

It’s essential as it contains the genetic code and has to be passed on to new cells without being damaged

Question 3

What monomer makes up DNA?

Answer 3

A nucleotide

Question 4

What is the structure of a DNA nucleotide?

Answer 4

Deoxyribose (pentose sugar)
A nitrogenous base (guanine, cytosine, thymine and adenine)
One phosphate group

Question 5

How is a polynucleotide made?

Answer 5

It’s created through condensation reactions between the deoxyribose sugar and the phosphate group where water is removed, creating a phosphodiester bond (strong covalent bond)

Question 6

How is the double helix created?

Answer 6

The DNA polymer occurs in pairs joined by hydrogen bonds between bases

Question 7

Where do hydrogen bonds form?

Answer 7

Between complementary base pairs e.g. cytosine and guanine & adenine and thymine

Question 8

What is RNA

Answer 8

A polymer of a nucleotide formed of a ribose, a nitrogenous base and a phosphate group

Question 9

What are the bases in RNA?

Answer 9

Adenine
Cytosine
Guanine
Uracil

Question 10

Difference between DNA and RNA?

Answer 10

The RNA polymer is a relatively short polynucleotide chain and it’s single stranded.
In structure, RNA is ribose and DNA is deoxyribose

Question 11

Function of RNA?

Answer 11

To transfer the genetic code from DNA in the nucleus to the ribosomes. Some RNA (rRNA) is also combined with proteins to create ribosomes.

Question 12

What is the process of DNA replication called?

Answer 12

Semi-conservative replication

(In the daughter DNA one strand is from the parental DNA and one strand is newly synthesised)

Question 13

What is the 1st step of DNA replication?

Answer 13

DNA helicase breaks down the hydrogen bonds between the complementary base pairs which causes the DNA double helix to unwind and separate.

Question 14

What is the 2nd step to DNA replication?

Answer 14

The separated strands will act as a template. Free floating DNA nucleotides within the nucleus will then align opposite the complementary base pairs.

Question 15

What is the 3rd step of DNA replication?

Answer 15

DNA polymerase joins the nucleotides together to make phosphodiester bonds

Question 16

What is the 4th step in DNA replication

Answer 16

Now we have our newly synthesised DNA combined with the template strand and that is the new molecule of DNA.

Question 17

Evidence for DNA replication

Answer 17

Watson and Crick- discovered structure of DNA (double helix) in ‘53 helped by Rosalind Franklin’s research on x-ray diffraction

Meselson and Stahl- conducted an experiment which proved DNA replication must be semi-conservative

Question 18

What is ATP?

Answer 18

Adenosine TriPhosphate is an immediate source of energy for biological processes.
Metabolic reactions in cells must have a constant, steady supply of ATP.

Question 19

Structure of ATP

Answer 19

A nitrogen-containing base (adenine)
A pentose sugar (ribose)
3 phosphate groups

Question 20

How is ATP made?

Answer 20

During respiration
Made from ADP + Pi (inorganic phosphate) by a condensation reaction using the enzyme ATP synthase

Question 21

When does ATP release energy

Answer 21

ATP releases energy when it’s hydrolysed into ADP + Pi using enzyme ATP hydrolase