Topic 1 - DNA + Protein Synthesis Flashcards
DNA stand for?
- Deoxyribo nucleic acid
DNA structure?
- 1 DNA molecule consists of 2 strands of repeating units (nucleolides)
- 2 strands twisted into double helix
What’s the monomer of DNA?
- made up of lots of nucleotides (joined together)
- deoxyribose sugar (DNA)
-Ribose sugar (RNA)
4 DNA bases?
- Guanine + cytosine
- adenine + thymine
Purine bases?
- Adenine + guanine
Pyramidine bases?
- Cytosine + thymine + uracil
DNA is a polymer of what?
- is a polymere of mononucleotides
What reaction forms a sugar phosphate bond?
- condensation
Where do mononucleolides join together from?
- Phosphate (of one nucleotide) and phosphate group of adjoining nucleotide
- Peter to free form for diagram
A base is attached to each sugar molecule
What do sugar and phosphate units make up?
- The ‘backbone’ of the nucleic acid
Base pairing:
A strands of double helix held by what type of bonds?
Bonds between the —?
- hydrogen bonds
-Between the bases
Single hydrogen bond can be —?
Collection they can be —?
- Weak singularly
- very strong collectively
Hydrogen bonds + phosphodiester bonds
Hydrogen bonds = between bases ( nitrogenous bases)
Phosphodiester= 5’ phosphate grp (of one nucleotide) + 3’ hydroxyl grp (of another)
( check freeform for diagram)
Function of DNA?
- heredity material responsible for passing G.I from cell to cell
How DNA adapted to do it’s job?
- Stable
- strands can separate + self - replicate
- large molecule that carries lots of info
- base pairs prevents corruption from outside chemicals or physical forms
describe what happens in DNA replication:
- DNA helicase catalayses the breaks down of hydrogen bonds, and seperation of the two DNA strands
- free nucleotides join onto their complementary base pairs on template strand
- adjacent nucleotides joined by phosphodiester bonds catalysed by DNA polymerase
- Condensation reaction
What are the two parts of Protein Synthesis called?
-Transcription
-Translocation
Protein synthesis
Describe what happens in Transcription:
-* mRNA is found in the nucleus*
- RNA polymerase catalyses the breakdown of hydrogen bonds, uncoiling DNA
- Template strand/anti-sense strand
- free nucleotides join onto their complementary base pairs with phosphodiester bonds. cataysed by RNA polymerase
- mRNA moves from nucleus through the pores and attach to ribosomes in cytoplasm ( site of photosynthesis)
what comes first
Translocation or Transcription?
transcription then photosynthesis
Protein synthesis
Describe what happens in Translocation:
- amino acids join to form polypeptide chains
- mRNA joins to ribosome on RER
- tRNA molecule with specific amino acid attached to its amino acid binding site, bind to mRNA via its anticodon
- hydrogen bonds btwn anticodon of tRNA + mRNA
- happends again- 2 amino acids form a peptide bond
- 3rd tRNA molecule joins -> first one leaves the ribosome
- process repeats forming a polypeptide chain until a stop codon is reached
name a start codon
AUG
what’s a codon?
what do they code for?
- triplet bases
- amino acids
bonds btwn amino acids?
- peptide bonds
examples of stop codons:
- UAG
- UAA
- UGA
not all genomes code for proteins
what are the non coding regions of DNA called?
itrons
what are the coding regions of DNA called?
extrons
Features of genetic code
and why it useful
- non-overlapping -> each triplet read once
- its degenerate -> more than one triplet codes for one amino acid
-> reduce effect of mutationd
what kind of mutations can be harmful?
give an example and how it was caused
sickle celled anaemia - mutated haemoglobin = deformed r.b.c
3 types of mutations:
deletion (frameshift)
insertion (frameshift)
subsition
what does frameshift mean
changes everything below that mutation
the genetic code is universal. meaning?
its the same in all organisms and species
