Dna

Question 1

What is DNA and RNA

Answer 1

Both essential for the function of living organisms. Both types of nucleic acid. Found in all living cells and carry information

Question 2

DNA ( Deoxyribonucleic acid)

Answer 2

Used to store genetic information (instructions needed to grow and develop from a fertilised egg to a fully grown adult)

Question 3

RNA ( Ribonucleic acid)

Answer 3

Similar structure to DNA
Main function is to transfer genetic information from the DNA to the ribosomes . Ribosomes themselves are made of RNA and proteins

Question 4

Nucleotide structure

Answer 4

DNA AND RNA are polymers of nucleotides. A Nucleotide is a biological molecule made from three different components. A pentose sugar ( sugar with 5 carbon ) nitrogen containing organic base and a Phosphate group

Question 5

Polynucleotide structure

Answer 5

Many nucleotides join to form polynucleotide strands ( or chains) join via condensation reaction between the phosphate group of one nucleotide and the sugar of another.
Forms a phosphodiester bond (phosphate group and two ester bonds).

Question 6

Sugar phosphate backbone

Answer 6

Chain of phoshates and sugar

Question 7

DNA structure

Answer 7

Double helix structure.
Formed by two separate strands that wind round each other to form a spiral. ( strands called polynucleotides)
DNA molecules are very long and coiled very tightly so genetic info can fit into a small space in the cell nucleus

Question 8

DNA nucleotide structure

Answer 8

Made from a phosphate group, the pentose sugar, deoxyribose and a nitrogen containing organic base
Has same sugar and phosphate, base on each nucleotide can vary though.
Four bases adenine, thymine, cytosine, guanine

Question 9

Complementary base pairing

Answer 9

Two DNA polynucleotide strands join together by hydrogen bonds between the bases. Each base can join with one specific partner called complementary base pairing. Adenine with thymine ( A - T) and guanine always pairs with cytosine ( G - C)

Question 10

Number of hydrogen bonds between each base?

Answer 10

Two hydrogen bonds between A (adenine) and T (thymine)
Three hydrogen bonds between C (cytosine) and G (guanine)

Two polynucleotide strands are antiparallel. Two of these strands twist to form a DNA double helix

Question 11

RNA Structure

Answer 11

Differs to DNA:
Sugar in RNA nucleotides is a ribose sugar (not deoxyribose)
Uracil (u) replaces thymine as a base and pairs with adenine
Nucleotide form a single polynucleotide strand (not double)
Strands much shorter than most DNA