Unit 1 Topic 3- Gene Expression Flashcards
What does RNA stand for?
Ribonucleic acid
What are the 2 stages of gene expression?
Transcription and translation
What is RNA made up of?
Nucleotides which consist of a base, a phosphate and a ribose sugar
Which bases are present in RNA?
Uracil, adenine, cytosine and guanine
Is RNA single stranded or double stranded?
Single stranded
What are the 3 types of RNA?
mRNA, tRNA and rRNA
What is messenger RNA (mRNA)?
It is transcribed from the DNA in the neucleus and translated into proteins on ribosomes in the cytoplasm (it carries a copy of the DNA code from the neucleus to the ribosome)
What is transfer RNA (tRNA) ?
It is found in the cytoplasm and carry a specific amino acid to the ribosome during translation.
What is the shape of tRNA?
A clover shape
What is ribosomal RNA (rRNA) ?
RNA that combines with proteins to create a ribosome
Describe the process of RNA splicing
• Introns are removed from the primary transcript
• exons are joined together to produce a mature transcript
Are exons coding or non-coding regions?
Coding regions
Are introns coding or non-coding regions?
Non-coding regions
What is alternative RNA splicing?
When different mature transcripts are produced due to the difference in sequence of exons
How many bases make up a codon?
3
Describe the structure of RNA
RNA is a single strand of neuclotides which consist of a phosphate, a ribose sugar and a base which can be adenine, uracil, cytosine or guanine
What is the process of transcription?
this process occurs in the neucleus, RNA polymerase moves along the section of DNA and unwinds it, then it adds complimentary RNA neucleotides to the 3’ end of the template strand to create an RNA primary transcript, when the RNA polymerase reaches the terminator at the 5’ end it breaks away from the DNA template strand.
what is the process of translation?
mRNA binds to a ribosome at the start codon.
tRNA molecules pick up specific amino acids and line them up according to complimentary base pairing with a section of the mRNA
The ribosome moves along to the next codon and a tRNA brings in the next amino acid.
A peptide bond forms between the two amino acids.
The first tRNA leaves the ribosome.
These steps are repeated until the mRNA stop codon is reached.
what is a polypeptide?
a chain of amino acids linked together by peptide bonds
