DNA & Inheritance Flashcards
What is meiosis
Sexual reproduction of gametes
What does each parent contribute in meiosis
One gamete which is made up of 23 chromosomes
Chromosomes are homologous which means
They are similar
Gametes are haploid which means
They have one set of chromosomes from each parent
Are somatic cells identical
Yes
What happens in meiosis one
DNA is replicated, recombination and cell division
What happens in meiosis two
Further cell division
What is chiasma
The exchange of genetic information between pair of chromosomes
What is recombinant chromatids
It is the crossing over of sister chromatids in a reciprocal exchange
What stages are in miosis one
Prophase, metaphase, anaphase, telophase, cytokinesis
What does meiosis two do
Separate single sister chromatids
What are the types of meiotic errors
Recombination errors, nondisjunction
What happens in recombination errors
Gene duplicates and two inversions and translations
What happens in nondisjunction errors
Results in trisomy e.g. down syndrome
How does DNA go from normal to mutant
Normal -> mutation -> mutant
. /
Repair
What is DNA damage
A mutation in the sequence of DNA
Mutations can occur in the
Germline or soma
Mutations can be positive or
Negative or neutral
How fast are mutation rates
Generally slow
Germline mutations produce
Heritable linage
Types of a pair of DNA
Base excision repair, nucleotide excision repair, recombination repair
What enzyme can you use to repair DNA
Polymerase for exonuclease activity can be used to remove by going from the 3 to 5 stand (opposite way to DNA replication)
What is recombination repair
Using other alleles to make a new part of a gene
What mutations happen in cystic fibrosis
Mutations in the Cl- channel causes mucus to build up and channel is locked, that means CL – can’t be transported outside the cell. Patient becomes more susceptible to pathogens
