1.3 Criteria Flashcards
What does gene expression involve?
Involves the transcription and translation of DNA sequences.
Name 3 types of RNA:
Messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA).
What does RNA nucleotides comprise of?
A ribose sugar, phosphate and one of four bases (C, G, A, U)
What is the name of the base U, that replaces thymine?
Uracil
What is the function on mRNA?
To carry a copy of the DNA code from the nucleus to a ribosome.
Where is mRNA transcribed from DNA?
In the nucleus
mRNA is translated into proteins by ribosomes where?
Cytoplasm
Each triplet of bases on mRNA is called what?
Codon
What does a codon code for?
specific amino acids
Why is a tRNA molecule folded?
Due to complementary base pairing.
What is the function of tRNA?
To carry a specific amino acid to a ribosome.
A tRNA molecule has an anticodon. What is this?
An anticodon is a triplet of bases at one end and an attachment site for a specific amino acid at the other end.
What does a ribosome comprise of?
rRNA and proteins
What is transcription?
The production of a copy of the genetic code on DNA as mRNA can move out of the nucleus .
As RNA polymerase moves along DNA, what does it do?
It unwinds the double helix and breaks the hydrogen bonds between the bases.
What is the primary transcript of mRNA made from?
Is made from RNA nucleotides using complementary base pairing.
How is the primary transcript used to produce the mature mRNA transcript?
It is spliced together
Are introns coding or non-coding regions of the primary mRNA transcript?
non-coding regions which are removed
Are exons coding or non-coding regions of the primary mRNA transcript?
Coding regions which are joined together to form the mature mRNA transcript
In the mature mRNA transcript do exons remain in the same sequence?
Yes, they do not change order
Where does the translation of mRNA into a polypeptide occur? And what else does it involve?
At the ribosome
Involves tRNA
What does sequential translation of mRNA codons ensure?
Ensures the correct sequence of amino acids in a polypeptide chain
What is the name of the codon at the start and end of a mature mRNA transcript?
Start and finish codons
How does an anticodon bind to mRNA codons?
By complementary base pairing
The genetic code is translated into a sequence of what?
Amino acids
How are amino acids joined together?
By peptide bonds
tRNA molecules leave the ribosome after doing what?
Delivering a specific amino acid
Different proteins may be produced from one gene as a result of what?
Alternative RNA splicing
Different mature RNA transcripts are produced from the same primary transcript depending on what?
Which exons are retained and which exons are removed
Why do polypeptide chains have to be folded into a 3 dimensional shape?
To form a protein molecule
Protein molecules are a result of what two interactions?
Hydrogen bonding and other interactions between individual amino acids
Is there a small or large variety of protein molecule shapes?
Large variety
What does the shape of a protein molecule determine?
The function of that protein
How is the phenotype determined?
By proteins produced by gene expression
What other factors can influence phenotype?
Environmental factors
