2.5 Flashcards
1
Q
How does DNA replicate?
A
Semi-conservative replication:
1) DNA helicase breaks H bonds and the helix unzips
2) Each original strand acts as a template strand. Free-floating DNA nucleotides are attracted to their complementary base pairs.
3) Condensation reactions join nucleotides together (catalysed by DNA polymerase). H-bonds form between bases and new strands
4) Each new DNA molecule contains one original DNA strand and one new strand.
2
Q
What is a mutation?
A
A change to the sequence of DNA which may be passed on to offspring.
3
Q
How do changes in gene-coding DNA lead to changes in cell function?
A
Changes in base sequence of DNA Change in mRNA bases Changes codons in mRNA Alters in amino acids in protein Changes protein structure Changes protein function Changes function of cell
