Nucleic Acids & Proteins Flashcards
Name the two types of nucleic acids.
DNA / RNA
Draw, label and name the monomer of nucleic acids
Nucleotide
Compare DNA and RNA
DNA has the pentose sugar deoxyribose whereas RNA has the pentose sugar ribose
DNA has the nitrogenous base thymine whereas RNA has the nitrogenous base uracil
DNA is double stranded whereas RNA is single stranded
Genome
The genome is all the genetic information in an individual or cell.
Components of eukaryotic gene.
Regulatory sequence
Promoter region
Start instruction
Exons
Introns
Terminator
Components of prokaryotic gene
Promotor region
Operator region
Start instruction
Exons
Terminator
Promoter region
RNA polymerase attachment site is upstream of all genes.
Regulatory gene
controls another gene, by coding for a transcription factor, like a repressor protein which can attach to the operator region.
Structural gene
A gene that codes for protein that becomes part of the structure or function of an organism.
Gene regulation
Gene regulation is the cellular control of amount, or timing of appearance, of the functional product of a gene.
Purpose of gene regulation
Save energy and allows for specialised cells (cells who may have the same genome but express different genes resulting in different proteomes)
Proteome
the entire set of proteins expressed by an organism at a given time.
If given the number of amino acids in a polypeptide, how do you work out the number of bases / nucleotides in the mRNA?
amino acids x 3 , then add 3 (stop codon)
If given the number of bases / nucleotides in mRNA, how do you work out the number of amino acids in the polypeptide?
Bases / nucleotides / 3, then minus 1 (due to 3 bases not coding for an amino acid as they are a stop codon)
If given the number of amino acids in a polypeptide, how do you work out the number of codons in the mRNA?
number of amino acids = number of codons , plus 1 (stop codon)
Transcription factors
Bind to operator region (prokaryotes) or regulatory sequence (eukaryotes) and either help transcription occur or repress it
Transcription
Transcription this means that
DNA unwinds and RNA Polymerase attaches to the promotor region for the _______ gene.
DNA template strand is copied into pre-mRNA via complementary base pairing using RNA polymerase.
pre mRNA undergoes RNA processing. Introns are removed, a 5’ methyl G cap and 3’ poly-A tail are added to form mRNA.
mRNA for _______ leaves the nucleus and goes to a ribosome.
Intron
Non-coding regions, do not code for the protein so are removed
Exon
Coding regions, do code for proteins so are kept
Purpose of adding 5’ methyl-G-cap
protect the mRNA from enzyme degradation (prevents enzymes breaking it down) and helps the ribosome to bind to mRNA to translate the protein
Purpose of adding 3’ poly-A-tail
protect the mRNA from enzyme degradation (prevents enzymes breaking it down) and allows mRNA to leave the nucleus