Gene Expression - Learning outcomes/ questions Flashcards
How much of the genes in a cell are expressed?
Only a fraction of the genes in a cell are expressed.
Transcription and translation involves three types of RNA. Name them.
Transcription and translation involves three types of RNA (mRNA, tRNA and rRNA).
Structure of RNA and base names.
RNA is single stranded and is composed of nucleotides containing ribose sugar, phosphate and one of four bases: cytosine, guanine, adenine and uracil.
Messenger RNA (mRNA) job is what?
Messenger RNA (mRNA) carries a copy of the DNA code from the nucleus to the ribosome.
mRNA is transcribed from DNA in the nucleus and translated into proteins by ribosomes in the what?
mRNA is transcribed from DNA in the nucleus and translated into proteins by ribosomes in the cytoplasm.
Each triplet of bases on the mRNA molecule is called a what and what does it code for?
Each triplet of bases on the mRNA molecule is called a codon and codes for a specific amino acid.
What happens due to due to complementary base pairing. (tRNA)
Transfer RNA (tRNA) folds due to complementary base pairing.
What does each tRNA molecule carry?
Each tRNA molecule carries its specific amino acid to the ribosome.
A tRNA molecule has a what at one end and a what type of site for a specific amino acid at the other end?
A tRNA molecule has an anticodon (an exposed triplet of bases) at one end and an attachment site for a specific amino acid at the other end.
Ribosomal RNA (rRNA) and proteins form what?
Ribosomal RNA (rRNA) and proteins form the ribosome.
What does RNA polymerase do along the DNA?
RNA polymerase moves along DNA unwinding the double helix and breaking the hydrogen bonds between the bases.
RNA polymerase synthesises what?
RNA polymerase synthesises a primary transcript of mRNA from RNA nucleotides by complementary base pairing.
In DNA, adenine is complementary to thymine, what is it complementary too in RNA?
Uracil in RNA is complementary to adenine.
RNA splicing forms a mature what?
RNA splicing forms a mature mRNA transcript.
The introns of the primary transcript are what type of region and do they stay?
The introns of the primary transcript are non-coding regions and are removed.
The exons are what type of region and are joined together to form what?
The exons are coding regions and are joined together to form the mature transcript.
Does the order of exons change splicing or not?
The order of the exons is unchanged during splicing.
Translation begins and ends with what?
Translation begins at a start codon and ends at a stop codon.
Anticodons bond to codons by what type of base pairing, and what does the genetic code become?
Anticodons bond to codons by complementary base pairing, translating the genetic code into a sequence of amino acids.
What type of bonds join the amino acids together?
Peptide bonds join the amino acids together.
Each tRNA then leaves what?
Each tRNA then leaves the ribosome as the polypeptide is formed.
Different mature mRNA transcripts are produced from the same what?
Different mature mRNA transcripts are produced from the same primary transcript depending on which exons are retained.
Polypeptide chains fold to form a what type of shape of a protein, and how is it held together?
Polypeptide chains fold to form the three-dimensional shape of a protein, held together by hydrogen bonds and other interactions between individual amino acids.
Proteins have a large what of shapes which determines what?
Proteins have a large variety of shapes which determines their functions.
