(3)- DNA and Protein Synthsis Flashcards
where is tRNA found
in the cytoplasm
why is tRNA described as a clover leaf
it is the result of hydrogen bonding between different bases
What is a anticodin
Sequence of the 3 bases
What is the role of the binding site of the tRNA
It picks up one particular amino acid from the vast numbers always free in the cytoplasm
What is the role of hydrogen bonds in tRNA
the tRNA molecules each carrying a specific amino acid line up along side the mRNA on the surface of the ribosome.
The anticodons of the tRNA line up with the codons of the mRNA held in place by hydrogen bonds between the corresponding bases
What is the role of the anti codon in the tRNA
Their function is to base pair with the codon on a strand of mRNA during translation. This action ensures that the correct amino acid will be added to the growing polypeptide chain
what is a mutation
is a permanent change in the DNA of an organism
what is gene mutation (Point mutation)
is a change in one or a small number of nucleotides affecting a single gene
an example of a gene mutation
when just one or a small number of nucleotides are miscopied during transcription during transcritpion
what are subsititions
is a type of point mutation in which one base in a gene is substituted for another
What are deletions
is a type of point mutation in which a base is complete lost
What are insertions
when an extra base is added into a gene which may be a repeat or a different base
What are chromosomal mutations
changes in the position of entire genes within a chromosome
What are whole chromosome mutations
is the loss or duplication of a whole chromosome
what is sickle cell disease
a genetic disease that affects the protein chains making up the haemoglobin in the red blood cells
What causes sickle cell disease
a point mutation
describe sickle disease
A change of one base in one codon changes a single amino acid in a chain of 147 amino acids but that change alters the nature of the protein as a result the haemoglobin molecules stick together to form rigid rods that give the red blood cells a sickle shape
What are the properties of sickle cells
They do not carry oxygen efficiently
they block the smallest blood vessels
They have a sickle shape
How does tRNA hold its clover leaf shape
This shape is the result of hydrogen bonds bonding between different bases
What is the role of anticodons
Their function is to base pair with the codon on a strand of mRNA during translation
what does 3 nucleotides make
1 amino acid
Why is DNA helicase important
it breaks the hydrogen bonds between the nitrogenous bases which allows the double helix strand to unzip to be replicated
What is a gene mutation?
change in the sequence of base pairs in a DNA molecule that may result in an altered polypeptide
What causes sickle cell anemia
Sickle-cell anaemia is caused by a point mutation in the protein haemoglobin.
What is swapped in sickle cell amniea
The amino acid glutamic acid is replaced with valine
What happens to the RBC sickle cell amenia
This causes red blood cells to become distorted, and they can no longer efficiently carry oxygen.
