FCB Fundamentals of Nucleic Acids

what do DNA/RNA do?

store, transmit and express genetic information

DNA and RNA are....

...nucleic acids which are condensation polymers of nucleotides

nucleic acids

condensation polymers of nucleotides

in what direction are DNA and RNA synthesised and why?

5' to 3' direction bc nucleotides can only be added to the 3' OH group

nucleotide structure

1. pentose (deoxyribose or ribose sugar)

2. phosphate on 5' C

3. nitrogenous base (C,G,A,T,U) on 1' C

DNA basic function

carries genetic information

where is DNA contained?

in chromosomes which are found in the nucleus of most cells but small amount are found in the mitochondria!

genetics

study of heredity and the variation of inherited traits

gene therapy

using genes to treat/prevent disease. might replace some drugs/surgeries in the future!

pharmacogenetics

application of genetic analysis to predict drug response, efficacy and toxicity. its used in prescribing to determine the best drug based on pt genotype for e.g.

congenital

present from birth

RNA basic function

important for gene expression & regulation and protein synthesis

where is RNA contained?

all throughout the cell e.g. nucleus, cytoplasm, ribosome etc.

DNA vs RNA nucleotide structure

DNA: H attached to 2' C

RNA: OH attached to 2' C

how are Cs numbered in nucleotides?

1' to 5' going from R->L where the top corner is acc an O

nucleic acid nitrogenous bases

Cytosine, Guanine, Adenine, Thymine (DNA only) and/or Uracil (RNA only)

thymine vs uracil structure

same except thymine has a methyl group also attached!

how to tell if its DNA or RNA based on nucleic acid structure?

1. check 2' C. if H attached = DNA, if OH attached = RNA

2. check if it has thymine or uracil NOTE: look for a hexagon w 2 carbonyl groups. if it has a methyl group also attached = DNA if no methyl group = RNA

adenine and guanine are...

...double ring purine bases

cytosine, thymine and uracil are...

...single ring pyrimidine bases

nucleic acid joining structure

phosphate joins 3' C of 1 pentose to 5' C of next pentose to get that repeating pattern

where are nitrogenous bases attached on nucleic acids?

1' C always

order of nitrogenous bases on nucleic acid...

...is important as it determines the genetic information of a molecule

DNA structure

double helix

RNA structure

single stranded

how are nitrogenous bases joined to each other in DNA?

hydrogen bonds

DNA double helix strand structure

they're antiparallel sister strands (complementary NOT identical!)

nucleic acid complementary base pairs

C+G

A+T/U

i.e. purine + pyrimidine

DNA grooves

minor groove: when strands are close together

major groove: when strands are far apart

NOTE: many anti-cancer drugs are groove binders!

DNA amount...

...is constant proving that they're the molecule of heredity

3 types of RNA

1. mRNA

2. tRNA

3. rRNA

what do the 3 RNA types do?

translate genetic code into proteins

how is mRNA generated?

during transcription, it's transcribed from DNA in the nucleus

what does mRNA do?

carries genetic code (codons) from nucleus to cytoplasm

what does tRNA do?

helps to decode mRNA sequence into a protein by carrying AAs to ribosome

where does tRNA carry AAs?

at 3' end

what is rRNA?

the structural and functional part of the ribosome

what do ribosomes consist of?

rRNA and proteins

ribosomes are the site of...

...protein synthesis and are a major antibiotic target e.g. tetracyclines

miRNA and siRNA

RNAs that degrade mRNA or block translation to regulate gene expression