Immune system + DNA Flashcards
What is meant by non-overlapping genetic code?
Each triplet is discrete, code is read one triplet at a time
Why are there three bases in each code?
2 points
Each amino acid needs to be coded for
Using three bases gives enough codes for each amino acid
Advantage of degenerate code?
If a mutation does occur, it reduces risk of amino acid being coded for changing
The last base in the triplet can be changed without having any effect on protein being synthesised.
Difference between Eukaryotes and Prokaryotes
Pro don’t have a nucleus/nuclear envelope
Pro don’t have membrane bound organelles
Pro have 70s ribosomes, Eu have 80s ribosomes
Pro have a cell wall
Effect of antibiotic investigation:
How should the lid be sealed?
Held on with tape (loosely sealed)
Prevent lid from falling off and prevent growth of anaerobic bacteria
Effect of antibiotic investigation:
What temp of incubation? Why?
27 degrees
Warm enough for bacteria to grow/reproduce
But prevents growth of pathogenic bacteria
Describe properties of globular proteins
Soluble
Hydrophobic outside
Hydrophilic inside
Describe Transcription
DNA unwinds in region of gene coding for required protein (DNA Helicase)
Free RNA nucleotides line up against complementary bases on antisense strand
They form complementary base pairing through hydrogen bonds
RNA Polymerase joins free nucleotides through phosphodiester bonds to form a strand
Strand separates from antisense to form pre-MRNA
In post transcirptional modification
MRNA is then cut into fragments by a splicesome
Introns are removed and exons are joined back together
Describe post transcriptional modification
Spliced by Splicesome
Cuts out introns and joins the exons together
Some exons may be spliced out as well
Various combinations of exons are formed
So mRNA is different to genetic code sometimes
Caps are placed on either end of the modified mRNA
So when it goes through the cytoplasm it doesn’t get damaged by enzymes in cytoplasm
How do scientists share their work?
3 things
Publish an article in scientific journal
Go to Scientific Conferences
Peer-review of their work by other scientists
Properties of HIV?
gp 120 receptor proteins on surface
has an envelope
has RNA
reverse transcriptase, integrase
Why are maternal antibodies passed down from the mother not long-lasting?
It is natural passive immunity
Level of antibodies becomes too low to give protection
As antibodies become broken down by kidneys
Primary immune response has not occurred
So there are no B or T helper memory cells made
Therefore over time agglutination will no longer occur and phagocytosis is reduced
