Protein Synthesis Flashcards
5difference between eukaryotes dna and prokaryotes
Eukaryotes DNA’s -
linear
associated with histones
has exons and introns
longer
Prokaryotes DNA’s -
circular
has exons only
shorter because doesnt have noncoding DNA
similarities between eukaryotes and prokaryotes DNA
both have double stranded dna
both have polynucleotides and both are polymers of nucleotides
both have phosphate groups
where are introns found
within a gene
what are the 4 types of RNA
Messenger RNA (mRNA) – formed during transcription.
Transfer RNA (tRNA) – involved in translation.
Ribosomal RNA (rRNA) – consist of a large and a small subunit, site of translation.
Interfering RNA (RNAi) – inhibits translation
describe mRNA
This is a single stranded polynucleotide chain.
· It is a complementary copy of a single gene, from the TEMPLATE strand of DNA.
· mRNA’s length will vary depending upon the number of bases that make up the gene, so it is much shorter than DNA.
what is a gene
· A gene is a sequence of nucleotides that codes for a primary structure of a polypeptide chain.
Contrast DNA and mRNA.
DNA is double stranded whereas RNA is single stranded
DNA is longER whereas RNA is shortER
Thymine in DNA whereas Replaced with uracil in RNA
Deoxyribose in DNA whereas Ribose in RNA
DNA has hydrogen bonds whereas mRNA doesn’t have hydrogen bonds
DNA has introns whereas mRNA doesn’t have introns
what is the role tRNA
The role of the tRNA molecules is to carry a specific amino acid to the RIBOSOME [site of protein synthesis].
what is a genome
complete set of genes in a cell
define proteome
full range of proteins that a cell is able to produce.
define loci
position of a gene within chromosome
what is an allele
a different version / form of a gene
what is the difference between introns and exons
Introns - non-coding sequences within a gene of DNA.
Exons - coding sequences within a gene of DNA.
describe the process of transcription
(DNA Helicase attaches to) unwinds DNA double helix at site to be transcribed.
· Hydrogen bonds between the two strands are broken, DNA strands separate.
· Only 1 strand acts as a template.
· Complementary free RNA nucleotides associate with exposed DNA bases via complementary base pair rules on the template strand only.
· Uracil to Adenine and Cytosine to Guanine
· RNA polymerase joins adjacent RNA nucleotides together (condensation reaction forming PHOSPHODIESTER bonds)
· Introns are now removed by SPLICING to produce mature mRNA
· mRNA passes out of nucleus via nuclear pore to the RIBOSOME (site of protein synthesis).
describe translation
mRNA binds to ribosome
Ribosome finds the START codon
Idea of two codons/binding sites
(Allows) tRNA with complementary anticodons to bind/associate with codon
(Catalyses) formation of peptide bond between amino acids (held by tRNA molecules) using energy from ATP
tRNA released as Ribosome moves along (mRNA to the next codon)/translocation described
Ribosome releases polypeptide into RER when the STOP codon is reached