Storing and using genetic information. Flashcards
What shape is a DNA molecule?
Double - helix
In terms of DNA bases, what does adenine bind too?
Thymine
What does Cytocine bind too?
Guanine.
What is thymine replaced by on mRNA
Cytosine.
DNA is bi-directional, what does this mean?
The strands go in the opposite direction. One starts at 5’ (5 prime) and ends at 3’, and the other one starts at 3’ and ends at 5’.
DNA replication is known as semi-conservative. What does this mean?
There is one recycled DNA strand in both new DNA strands.
What enzyme forms new DNA strands.
DNA polymerase.
DNA is formed in fragments, what name is given to these fragments?
Okazaki fragments.
What are 3 bases in DNA known as, and what do they code for?
Codon - code for 1 amino acid.
The bases are DEGENERATE. What does this mean?
There are 64 possible codons - but only 20 amino acids. The is because multiple codons may form the same animo acid (can have different 3rd letter).
Before DNA is converted to mRNA, the DNA must be slightly loosened. How does this occur.
Histone must be removed by enzyme - or displaced by CHROMATIN REMODELLING COMPLEXES.
What is the initiation codon, why, what etc
The first codon that enzymes with start transcription on. This is methionine - as it only has one possible codon.
What is an example of post- transcriptional modification?
Alternative splicing. Gets rid of introns (where coding does not occur.) Remains exons can then be chopped about, depending what protein you want to make.
Where does translation occur?
In ribosomes - in the cytoplasm or on the rough endoplasmic reticulum.
What is tRNA accatched too in the cytoplasm
amino acids.
