1.3 Gene Expression Flashcards
What is gene expression?
The process by which specific genes are activated to produce a required protein
What are the 3 types of RNA?
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Ribosomal RNA (rRNA)
How many strands does RNA have?
One strand
What does an RNA nucleotide contain?
- Ribose Sugar
- Phosphate
- A Bass
What are the 4 RNA bases?
- Adenine
- Uracil
- Guanine
- Cytosine
What are the RNA base pairings?
- Adenine and Uracil
- Guanine and Cytosine
Where is mRNA made?
In the nucleus
What does mRNA do?
It carries a copy of the DNA code from the nucleus to the ribosomes in the cytoplasm where it is translated into a protein
What is the name of the first stage of protein synthesis?
mRNA
Why is tRNA folded?
Due to the complementary base pairing within the strand
What is the role of tRNA?
Each molecule can carry one specific amino acid from the cytoplasm to the ribosome
What do tRNA molecules have for amino acid?
An attachment site at the top
What are ribosomes made of?
rRNA and protein
What is each triplet of bases on mRNA called?
A codon
What does each codon code for?
A specific amino acid
What is the name of the 3 bases that are exposed on each tRNA molecule?
An anticodon
How are proteins made?
By joining together amino acids in a specific sequence
Where does transcription occur?
The nucleus
What does transcription produce?
A strand of mRNA complementary to a region of DNA called a gene
How is the order of amino acids dictated?
By the order of the bases on the DNA
What are the 6 stages of transcription?
1- DNA unwinds and RNA polymerase breaks hydrogen bonds
2- Free RNA nucleotides pair with DNA bases
3- Sugar-phosphate bonds form between RNA nucleotides
4- This requires ATP and the enzyme RNA polymerase
5- Introns are removed from the primary mRNA transcript to form the mature mRNA transcript
6- Mature mRNA leaves the nucleus
What are the requirements for transcription?
- DNA template
- Free RNA nucleotides
- RNA polymerase
- ATP
What is translation?
The synthesis of a protein in the form of a polypeptide chain at ribosomes
What does translation begin and end with?
A start and stop codon
What are amino acids joined together by?
Peptide bonds to form polypeptide
