Nucleic Acids and Nucleotides

What are Nucleic acids?

Are large molecules found in the nucleus. There two types, DNA and RNA

What is a nucleotide ?

Acts as the basic building blocks for Nucleic acids

what are the three sections within a nucleotide ?

Phosphate group, Pentose/sugar, Base

what is the name of the bond that forms between

Polydiester bonds

what is the name of the polymer of a nucleic acid

polynucliatide

what does DNA stand for

Deoxyribose nucleic Acid

what is the difference between Deoxyribose and Ribose?

what does Pyrimidines mean ?

smaller carbon rings bases. Thymine and Cytosine

what does Purines mean ?

larger, carbon rings , Adenine and guanine

what are DNA ligase

they are enzmyes that catalyse the formation of phosphodiester bonds. It joins together shorter polynucloetide strands

what does complimentary base pairing mean? Give examples

hydrogen bonds will form between two bases. This will only happen if the bases are complimentary. For example A and T, G and C, and in RNA A and U

how many bonds form between each complimentary base?

A and T two bonds

g and c three bonds

a and u two bonds

what are the three types of RNA

mRNA: messenger rna

tRNA: transfer RNA

rRNA: ribosomal RNA

What is tRNA

red = anti condonds, which bind to complimentary bases in mrna

circle = amino group

what does a nucleotide look like ?

what does nucliotides bonding look like ?

what is the difference between Deoxyribose and ribose

ribose as one more oxygen

Explain how DNA replication works

1- DNA helicase breaks the hydrogen bonds between the complimentary bases, unzipping the DNA, causing the two polynucleotides to move away from each other

2- then free DNA nucleotides line up with their complimentary bases, hydrogen bonds form but not phosophidester bonds

3- DNA polymerase then catalyses the formation of phosphodiester bonds, condensation reaction

semi conservative replication

Why is DNA replication described as semi conservative?

Strands from original DNA molecule act as templates. New DNA strands contain one old and one new strand

What is the role of DNA helicase in dna replication

Brakes the hydrogen bonds between bases

What is a mutation

An alteration to the DNA base sequence, usually that arise during DNA replication

Explain how transcription works?

1- DNA helicase catalyse the separation of the DNA strands, by braking the hydrogen bonds between the complimentary bases

2- free RNA nucleotides are attracted to their complimentary bases on the exposed DNA strand ( adenine bonds with uracil in RNA), temporary hydrogen bonds

3- RNA polymerase catalyse the formation of phosphodieseter bonds

4-the non coding strand then leaves through the nuclear pores

What is a codon ?

Three bases that will code for a specific amino acid

Explain what happens during translation

1- ribosomes moves along mRNA

2- tRNA anticodons attach to mRNA codons forming temporary hydrogen bonds

3- condensation reaction occurs between the amino acids on the tRNA forming peptide bonds

4- tRNA will then leave, leaving behind its amino group

5- this chain will increase, until it reaches the stop codon, the chain will then fold up on itself to make a protein

What catalyses the forming of phosphodiester bonds

DNA/RNA polymerase

what is ATP

adenosine triphosphate, nucleotide derivative, adenine as base and has 3 phosphate groups

what is ATP hydrolase

energy released when ATP is hydrolysed to from ADP and a phosphate group

how is the structure of guanine different from adenine

has a c=o

how to tell the difference between CUT

c has only one c=o

t has a methyl group