1B

Function of DNA

Function of DNA

To store genetic information

Name the 3 biological molecules in DNA

Deoxyribose sugar / A phosphate group / A nitrogen-containing base (A/T/G/C)

Name the 3 biological molecules in RNA

Ribose sugar / A phosphate group / A nitrogen-containing base (A/U/G/C)

Name of the sugar and phosphate chain in a polynucleotide

Sugar-phosphate backbone

How many hydrogen bonds are between A and T

2 hydrogen bonds

How many hydrogen bonds are between C and G

3 hydrogen bonds

What does antiparallel mean?

Running in opposite direactions

What is the key term for ‘specific base pairing’?

Complementary base pairing

DNA replicates by…

Semi-conservative replication

Step 1 of semi-conservative replication

DNA helicase breaks H-bonds between bases of the 2 polynucleotide. This makes the helix unwind

Step 2 of semi-conservative replication

Original strand acts as a template for a new strand. Complementary base pairing means that free-floating DNA molecules are attracted to their complementary exposed bases

Step 3 of semi-conservative replication

Condensation reaction joins the nucleotides of the new strand together, this is catalysed by DNA polymerase. Hydrogen bonds also form between the bases.

Step 4 of semi-conservative replication

Each new DNA molecule contains one original strand and a new strand of DNA.

Who are the 2 people that discovered / determined the structure of DNA?

Watson and Crick

Who are the 2 people that came up with the theory of semi-conservative replication?

Watson and Crick

Who are the 2 people that provided evidence / validated the theory of semi-conservative replication?

Meselson and Stahl

What did Watson and Crick do?

Determine the structure of DNA and came up with the theory of semi-conservative replication

What did Meselson and Stahl do?

Provided evidence / validated the theory of semi-conservative replication

Name the 5 useful properties of water

Important metabolite / High latent heat of vaporisation / Buffer temperature change / Good solvent / Cohesive

How is water an important metabolite

Many metabolic reactions involved a condensation or hydrolysis reaction

How does water have a high latent heat of vaporisation?

Takes lots of energy (heat) to break hydrogen bonds between water molecules.

Why is water having high latent heat of vaporisation useful?

Lots of energy (heat) is used up when water evaporates which provides a cooling affect for living organism, without losing too much water

How does water buffer temperature change?

The hydrogen bonds between water molecules can absorb a lot of energy.

Why is water being able to buffer temperature useful?

Provide stable habitat for organisms under water / the water inside organisms can maintain a stable temperature (also help maintain a constant body temperature)

What enzyme is used for the condensation of ATP?

ATP synthase

What enzyme is used for the hydrolysis of ATP?

ATP hydrolase

What are the products of hydrolysis of ATP

ADP and inorganic phosphate (Pi)

What is the (MAIN) use of inorganic phosphate (from the hydrolysis of ATP)

Phosphorylation, when the Pi is added to another compound, making the compound more reactive

Name the 4 inorganic ions

Iron / Hydrogen / Sodium / Phosphate (ions)

What is an inorganic ion?

Ion that does not contain carbon