Gene Expression: From Gene to Protein (Transcription + RNA Processing) Flashcards
RNA stands for
Ribonucleic acid
RNA is a
A nucleic acid that consists of a long chain of nucleotides
What are the differences in DNA and RNA
- The sugars are different
- RNA is generally one stranded, while DNA is usually a double helix
- The bases are different
- RNA had more jobs
- There are more types of RNA
What is the sugar of RNA
Ribose (has one more oxygen than deoxyribose)
What is the sugar of DNA
Deoxyribose
What are the bases of DNA
G C A T
What are the bases of RNA
G C A U
How many types of RNA are there (that we learned abt)
3
What are the three types of RNA
mRNA, tRNA, rRNA
mRNA is an abbreviation for
Messenger RNA
tRNA is an abbreviation for
Transfer RNA
rRNA is an abbreviation for
Ribosomal RNA
What is the job of DNA
Pass on genes
What helps enzymes differentiate between RNA and DNA?
The different bases which have chemical differences
Central dogma of biology
The theory that states that DNA codes for RNA and RNA codes for proteins
Does the central dogma of biology applied everything
No In reality it has many exceptions but it is the standard
What is RNA’s General job
Protein synthesis (Controls the assembly of amino acids into proteins)
What is the job of mRNA
RNA molecules that carry the complement of the DNA to ribosomes to make proteins
What is the job of rRNA
Catalyzes proteins synthesis translation and builds peptide bonds
Make subunits of ribosomes
holds ribosomal proteins in place
helps locate beginning mRNA message
What is the job of tRNA
transfer an amino acid from the cytoplasmic pool of amino acids to grow the polpeptide in a ribosome. tRNA enables translation of mRNA codon into a certain amino acid
What is on the top of the tRNA molecule
Amino acid attachment site
What is at the bottom of the tRNA
Anti-codons that pair with the bases on the mRNA molecule
Another name for transcription is
RNA synthesis
Where does transcription take place in eukaryotes
Nucleus
Transcription
Where are most of the production of RNA takes place
segments of DNA service templates to produce complementary RNA molecules
Where does transcription take place in prokaryotes and why
Cytoplasm bc they dont have a nuclear envelope
What enzyme is needed in transcription
RNA polymerase
RNA polymerase
Is similar to DNA polymerase
What direction does RNA polymerase work in
Five prime to three prime
(But the mRNA molecule works on goes from three prime to five prime)
How many steps are in transcription
2
What are the two steps of transcription
1) RNA polymerase binds to the promoter
2) The RNA polymerase separates the DNA strand and uses one strand of DNA as a template to form a complementary strand of RNA by connecting the corresponding bases
Promoter region
Regions of DNA that have specific basically says which indicates where RNA polymerase should start making RNA bc it has the starting point
What is the intermediate step between transcription and translation
RNA processing
In what type of cell does RNA processing take place in
Only eukaryotes
Where does RNA processing take place
Nucleus
How many steps does RNA processing have
3
What are the three steps of RNA processing
1) mRNA splicing
2) 5’ cap
3) poly-a-tail
mRNA splicing
Cutting out the junk mRNA created during transcription
How many steps does mRNA splicing have
2
What are the two steps of mRNA splicing
1) Nuclease takes away introns to make DNA legible
2) The remaining pieces of mRNA (exons) are sliced back together to form the final mRNA
Ribonucleotide
Individual monomer of RNA (Nucleotides for RNA)
Nuclease
Enzyme that breaks down nucleic acids into nucleotides
Introns
Junk mRNA that is cut out in mRNA splicing 
Exons
MRNA left behind when introns are cut out
________ never serve as ______ but ______ can sometimes service ______
Introns exons exons introns 
Introns and exons play a role in evolution because of
Slight changes in forms of mRNA
During mRNA spicing mRNA is known as
Nuclear RNA
5’ cap
Adding a tri phosphate G nucleotide in the opposite direction to the five prime end of the mRNA
What is the purpose of the five prime cap
Tricks the enzyme that chops up DNA so that it doesn’t
What is another purpose of the Five prime cap
It is also helpful so that ribosomes recognize the mRNA so they can attach to the mRNA for translation
Poly means
Many
The a in poly-a-tail stands for
Adenine
Poly-a-tail
Add hundreds of adenines (unimportant nucleotides) to block Nuclease from chopping useful DNA on the three prime end
The sequence of nucleotide bases in an mRNA molecule is a set of instruction that gives
The order in which amino acid should be joined to form a polypeptide chain
what did the beedle and Tatum experience try to prove
tried to prove that every gene codes for a specific enzyme
beedle and Tatum experiment
experiment where they worked with bread mold and exposed them to x-rays to create mutants (bad enzymes) that have diff mutations in diff genes to see what mutation causes the arginine to not grow
What are the main steps of transcription
1) DNA codes for mRNA
2) RNA –> polypeptide chain
why and what did beedle and tatum experiment
genes code for enzymes bc if there is no gene (bc mutation) then there is no enzyme to grow arginine
MM stands for
minimal amt
MM meaning
everythig (minimal) needed to grow arginine
path of peoples beliefs of how DNA codes for life and stuff
1 gene : 1 enzyme –> 1 gene: 1 polypeptide –> 1 gene: 1 polypeptude chain
how did this theory (1 gene : 1 enzyme –> 1 gene: 1 peptide –> 1 gene: 1 polypeptide chain) come to be
ppl discovered that proteins can be other things than enzymes and they also discovvered that a gene can code for a polyppeptide chain bc proteins can be made of multiple polypeptides
transcription
the synthesis of RNA using information in DNA
translation
produces mRNA. Translation is the synthesis of a polypeptide, using information in the mRNA.
way to remember the difference between transcription and translation
transcript: DNA –> RNA are the same language
translate: RNA –> proteins are diff languages
transcription overview steps
1) DNA –> pre-mRNA
2 )RNA processing to make mRNA
3) go to nucleus
4) mRNA–>polypeptide
Triplet
DNA codes that are always written in three
Codon
three consecutive mRNA bases
pair for RNA
U and A
G and C
Anticodon
tRNA bases which complement codons and are always in groups of three
___ DNA bases, ___ mRNA bases, ___ tRNA = ___ amino acid
3,3,3,1
genetic code
language of DNA, mRNA, tRNA
How many strands are transcribed explain
1 strand PER GENE bc complementary DNA so the other one is js copied
** doesn’t always have to be me whole strand can js be one gene and the other strand has another gene
Promoter region located where
Segment if dna before transcription unit on the 5’end
Terminator
Segment of DNA where transcription stops
Where is terminator located
Transcription unit
Transcription factor proteins
Proteins that locate the promoter region and grab other factors and also other factors and also RNA polymerase to make the transcription initiation complex
Termination of transcription in prokaryotes
RNA polymerase stops at the terminator and makes mRNA
Termination of transcription in eukaryotes
RNA passes by the terminator one more time and then another TATA box and a few more bases and then it stops and makes mRNA
Ribozyme
RNA catalysts (like how enzymes are protein catalysts) that they catalyze their own reactions
snRNA
Small nuclear RNA
One gene codes for on polypeptide chain. True or false
False can be multiple
Spliceosome
they have snRNPs tat recognize the introns so they know where to cut the DNA and then they also stick the exons together
transcription factor
DNA binding proteins that control the expression of genes
what is the part of the snRNP that recognizes the intro
the RNA
TATA box
short region of DNA that is located about 20 - 30 base pairs away from the start gene containing the sequence TATATA…. or TATAAAAA….
what is the function of the TATA box
binds a protein that helps position RNA polymerase by marking a point just before the beginning of a gene
examples of transcription factor
the one that recognizes the TATA box
transcription initiation complex
its a thingie thats made of transcription factors and RNA polymerase that binds to the promoter region to start transcription
aminoacyl-tRNA synthetase
an enzyme that joins each amino acid to the appropriate tRNA; theres a diff one for each amino acid
what is aminoacyl-tRNA synthetase powered by
ATP
what is protein synthesis powereed by
hydrolyzation of GTP
translation initiation complex
Consists of mRNA, tRNA (holding the first amino acid of the polypeptide), the small ribosomal subunit, and the attachment of a large ribosomal subunit.
