Genes Flashcards
What is genetic code?
A set of rules that nucleotides follow that determines how genetic information stored is .transcribed and translated into protiens.
What does genetic code consist of?
Universal: All organisms use the same sets of codons used for amino acids
Non-overlapping triplet nature All triplet and codons are read independantly
UnambigousEach codon codes for only one amino acid
Degenerate Amino acids may be coded by multiple different codons.
What is grouping of three nucleotides in DNA called?
Triplets
What is the grouping of three nucleotides in RNA called?
Codon
Do all codons code for the protiens structure?
Nahhhhh brother wbt STOP AND START codons in protiens synthesis.
What is the start codon in protiens and stop codons
AUG ( Methionine)
Stop codons:
UAA,UAG,UGA
What is Gene expression?
It is when a part of a gene is used by the cell for gene products or non coding strands of RNA
Remeber this doesnt ALWAYS mean PROTIEN
the non cododing thing yeah is like for tRNA and rRNA
What are the 3 basic steps for Protien Synthesis(In eukaryotes)
1.Transcription
2.RNA processing
3.Translation
What is Transcription
Definiton?
Transcription is the making of pre/mRNA which contains information needed based off DNA by the help of RNA polymerase.
What happens in Transcription?
FULL MARK ANSWER
- RNA polymerase and transcription factors attatch to the promoter reigion and DNA is then unzipped by the polymerase
- The template strand of DNA is read across in a 3’-5’ , adding free floating COMPLEMENTARY nucleotides to the bases on the template strand. to synthesise a mRNA strand In a 5’-3’ direction, where uracil is paired with adenine.
The RNA polymerase stops transcription when it reaches the termination sequence of the gene, which then pre-MRNA is relased.
DNA is recoiled and winded back.
What strand is read by rna polymerase in DNA
Template strand
Explain RNA processing
Splicing occurs, where the introns in the pre-mrna is removed by spliceomes and the exons are spliced together
A 5’ methyl cap is added and a 3’ poly-Adenine tail is added.
Why is RNA processing done, like the addition thinng
To prevent the mRNA from degrading and to assist from binding to the ribosome during translation
Explain Translation in protien synthesis
1.Ribsome binds to the 5’ end of the mRNA strand, and a TRNA molecule anticodon pairs with the start codon and brings the first amino acid.
2.Ribosome reads througout the mRNA strand brings trna anticodons that are complemntary to the codons of the mrna strand and brings the specific amino acids, forming a growing polypeptide chain connected by peptide bonds via condensation reactions.
3.When the stop codon is read translation terminates and the ribososome detatches and the polypeptide chain is released to be folded in endoplasmic reticulum.
what happens to the trna molecule after delivering a amino acid
it detatches and goes away to pick up the respective amino acid in the cell
What is upstram and downstream
5’ is up
3’ is down
What is gene regulation?
It is the control of gene expression by turning on and off transcription of a gene product.
Why is gene regulation important?
- Saves energy by not producing gene products when not needed
- Prevents accumalation of protiens, which can be toxic to the cell
- Allows cells to differentiate and specilalise during embryo development.
What are the two types of genes involved in gene regulation?
- Structural genes
- Regulatory genes