week 2 protein synthesis Flashcards
Transcription
(1st process) process in which mRNA is made from DNA, occurs in nucleus
Translation occurs in _______ and is the _______ process in which _______ is made from _____.
cytoplasm, second, protein, mRNA
protein synthesis
DNA-> Transcription-> mRNA-> Translation-> Protein
Genes are the
recipe to make a protein-segment of DNA that codes for protein
During transcription a ___ is used as a template to make mRNA.
Gene
Promoter
Found at the beginning of a gene (starting point of a gene)
Terminator
Identifies the end of a gene (GGGGG)
Promoter is _____ when the body is not producing that protein.
Inactive
Promoter must be ____ when it is time to produce that protein.
Activated
What activates a promoter?
Transcriptional factors
When are the transcription factors produced?
When the body need the protein to be produced
Transcriptional factors are usually ____.
Hormones
step 1 Transcription: Promoter activation
Transcriptional factors (TF) bind to the promoter and activate it. (makes them visible)
Step 2 Transcription: Enzyme binding
Activation of the promoter causes an enzyme called RNA Polymerase (RP) to arrive and bind to the promoter, causing the gene to unwind.
Step 3 Transcription: mRNA Synthesis
RNA Polymerase (RP) travels along the gene and places complimentary nucleotides until it reaches the terminator, then it stops. Creating the mRNA (immature)
Step 4 Transcription: mRNA Release
RNA polymerase encounters Terminator-> detaches from gene-> primary mRNA released-> TF & RP degrades-> then promoter is inactive
Primary mRNA (immature mRNA)
immature mRNA contains introns and exons
Introns
junk information, does not code for anything
Exons
Important information, codes for protein
Mature mRNA should ONLY contain ______.
Exons
Step 5 Transcription: mRNA editing
Process that matures mRNA, Two steps: removal or introns & adding cap and tail
Spliceosomes
enzymes that remove the introns and combine the exons
Methyl Group
The cap (chemical group)
Poly “A” Tail is made up of
multiple adenine nucleotides
Step 6 Transcription: Release of mature mRNA
Mature mRNA leaves the nucleus and enters the cytoplasm , then translation will start
Mature mRNA has _____.
Nucleotides
mRNA is a ____.
Polynucleotide
Every three nucleotides on a mRNA is a _____.
Codon
Codons represent an _____ _____.
Amino Acid, 1 codon = 1 amino acid
Methionine is an ____ ____.
Amino Acid
mRNA contains a ______ in the form of ____ that code for specific ___ ___.
message , codons, amino acids (proteins)
Codons are the _____ ____.
genetic code
There are __ codons in total and they code for __ amino acids.
64, 20
Four most important codons
AUG, UAA, UAG, UGA
AUG is a :
start codon, starts translation, represents methionine
UAA / UAG / UGA are:
stop codons, stops translation, codes for no amino acid
Translation is the process in which _____ is made from ____ and occurs in the _____.
protein, mRNA, cytoplasm
Three steps of translation:
Initiation, Elongation, Termination
The three type of RNAs needed for translation:
Messenger RNA (mRNA), Transfer RNA (tRNA), and Ribosomal RNA (rRNA)
rRNA function:
holds mRNA together, during translation allows appropriate tRNA to enter
rRNAs have two subunits :
1) small subunit (40s) & 2) Large subunit (60s)
What size is the small rRNA subunit
40s
what size is the large rRNA subunit
60s
What is the importance of tRNA in translation?
They are the molecules that carry the amino acids during the process of translation
tRNA structure:
it has two arms, T shaped, Anticodon arm & amino acid arm
Anticodon arm of tRNA
goes across horizontally, contains nucleotides which are complimentary to the codon found on mRNA
Amino Acid Arm of tRNA
Vertical to anticodon arm, contains the amino acid which is represented by the codon
Initiation is the process in which
everything is gathered together (mRNA/tRNA/rRNA) and translation starts
Elongation
when the polypeptide chain gets longer (ribosome moves a codon over-> new tRNA comes in-> amino acid makes a bond-> that tRNA leaves and the new tRNA comes in
Termination:
Tells us translation is ending because ribosome came across a stop codon, everything then breaks apart and polypeptide chain enters Golgi apparatus
What are the two large subunit types of rRNA?
A site and P site
A site of rRNA:
allows tRNA to enter the ribosome
P site of rRNA:
allows tRNA to exit the ribosome
