3.1.5.1 Structure of DNA and RNA

What is a nucleic acid

Polymers of nucleotides which contain genetic information

How is DNA protected from mutations

By forming a double strand

What base pairs does DNA contain

Cytosine, Thymine, Guanine, Adenine

What is the function of mRNA

To transport information from nucleus to ribosomes

What is the function of tRNA

To bring the amino acid to a ribosome

What is the function of rRNA

To form part of the ribosome structure with proteins

What bases make up RNA

Adenine, Uracil, Guanine, Cytosine

What is the full name of DNA

Deoxyribonucleic acid

What is the full name of RNA

Ribonucleic acid

What is the general function of DNA and RNA

To build proteins and carry information

What is the function of DNA

To hold or store genetic information

What is the function of RNA

To transfer the genetic code from the nucleus to the ribosomes

What molecules make up a nucleotide

A pentose sugar, a nitrogen containing base and a phosphate group

Define nucleotides

Repeating monomers of DNA and RNA

What is the difference between an RNA and DNA sugar

DNA contains deoxyribose sugar with H and the second position, RNA contains ribose sugar with OH in the second position

What is the difference between DNA and RNA bases

RNA contains a uracil base instead of a thymine

Define and give examples of purines

A nitrogenous base molecules with a double ring structure, such as adenine and guanine

Define and give examples of pyrimidines

A nitrogenous base molecule with a single ring structure, such as cytosine, thymine and uracil

Describe a difference between the structure of DNA and RNA

DNA is double stranded in a double helix, RNA is relatively short single strands

What bond forms between nucleotides

A condensation reaction forms a phosphodiester bond

How can the double helix strands be described

As antiparallel strands

Describe the joining of two bases

Complementary base pairings are joined with hydrogen bonds

How many bonds does thymine and adenine have

2 hydrogen bonds

How many bonds does cytosine and guanine have

3 hydrogen bonds

Describe an RNA polymer

A relatively short, singular polynucleotide strand

Name the types of RNA

messenger RNA, transfer RNA and ribosomal RNA

Define a ribosome

A small organelle which are the site of protein synthesis and translation

Where are ribosomes found

Either free in the cytoplasm or attached to the rough endoplasmic reticulum

Describe the difference between prokaryotic and eukaryotic ribosomes

Eukaryotic ribosomes are 80s (60&40 subunits), prokaryotic ribosomes are 70s (30&50 subunits)

Describe the structure of a ribosome

A small and large subunit, where the large unit is the sight of translation

Who discovered DNA

Friedrich Miescher in 1800s

Who discovered the double helix structure of DNA

Watson and Crick in 1953

Describe why DNA nucleotides are added in the 5’ to 3’ direction

DNA polymerase is specific and the 5’ and 3’ ends of nucleotides are different shapes and therefore can only be complementary with the 3’ end of a developing strand

Describe how the structure of RNA differs from DNA

RNA is single stranded, contains ribose sugar, uracil instead of thymine

Suggest how changing the sequence of DNA nucleotides can affect the final product the DNA codes for

Different sequence of amino acids produces a different tertiary structure so the protein can no longer function