Gene Expression and DNA Technologies Flashcards
What do proteins do?
Control many cell processes such as the rate of cellular metabolism.
Are essential to cell structure and function.
Provide the essential link between DNA and the functioning cell.
What does DNA do?
Determine the order of amino acids in a protein and therefore determine the protein’s structure and function.
How many nucleotides are needed to code for one amino acid?
3
Compare DNA and RNA.
DNA: Contains sugar deoxyribose Is double stranded Contains Thymine, Cytosine, Guanine and Adenine Is much longer than RNA
RNA: Contains sugar ribose Is single stranded Contains Uracil, Cytosine, Guanine and Adenine Is shorter than DNA (usually < 4 kb)
Describe gene expression.
Is the process where DNA directs proteins synthesis.
Refers to a gene being ‘turned on’ to produce a polypeptide OR Is the process of rewriting a gene into a protein.
Involves transcription and translation.
Define a promoter.
A regulatory area at the start of a gene that acts as the binding site for RNA polymerase.
Allow different genes to be expressed in different sets of cells within the same genome.
Define genes.
Sections of DNA that code for proetins.
The functional units of heredity.
Expressed when they are transcribed into messenger RNA (mRNA) and then translated into a protein.
Define triplet.
The 3 nucleotides or base code on DNA
Define codon.
The 3 nucleotides or base code on RNA
Define RNA Polymerase
The molecule that transcribes the gene
What does a promoter do?
Ads as a region for the RNA Polymerase to bind to to start transcription.
What does a terminator do?
Indicates where RNA Polymerase should stop transcribing.
What is the significance of the anti-parallel nature of DNA?
Transcription and translation occur only in 5’ to 3’ direction (polymerase work only 5’ to 3’ direction because the OH on the 3’ is the active site for forming the phosphodiester bond).
Describe transcription.
It is the first step of gene expression.
A segment of DNA is transcribed into mRNA.
In eukaryotes, transcription takes place in the nucleus.
In prokaryotes, transcription takes place in the cytoplasm
What is the role of messenger RNA (mRNA) in protein synthesis?
Carries a copy of the genetic instructions from the DNA (master instructions) to ribosomes in cytoplasm.
Rate of protein synthesis can be increased by making many copies of identical mRNA from the same piece of DNA.
