Flashcards in MCBG 15 - More mutations and techniques Deck (21):
What's a Mutation?
A mutation is a change in a DNA sequence
What's a somatic mutation?
mutations occur in the eggs or sperm, affect all cells in the body and can be passed on to offspring
What's a Germ line (genetic or hereditary) mutation?
mutation occur in a body cell and is not passed on to offspring
What are the functions of DNA POLYMERASE? 2
Forms strands of DNA from bases
Why are RNA mistakes less worrying? 3
RNA is not long term ( they get degraded especially if they are "bad")
RNA is not inherited
Name 3 symptoms of Mitochondrial DNA conditions?
In a genetic pedigree tree what signs would you look for?
1) Only inherited from affected mothers.
2) Children of affect mothers are all affected
Why could it be bad to inherit multiple copies of a chromosome?
If the genes function to slow growth, the extra copy may be fatal to the cell. However, ifthe genes promote growth, the cell may grow uncontrollably, leading to
Explain how an ovum is formed? Processes, name, N?
Oogonium2n(Mitosis to form more) -[maturation]-> Primary Oocyte2n+Polary body-[Meiosis1]->Secondary Oocyte2n -[Meiosis2]-> Ootide + 3 polar bodies -[Maturation]-> Ovum
The oocyte becomes arrested twice. One in meiosis 1 and once in meiosis 2. What stage of each of these?
MEI1 - Prophase 1
MEI2 - Metaphase 2
What comes before an oogonium/spermatogonium?
Primordial Germ Cells
Do female PGCs and then oogonia and then primary oocytes
increase hugely in number in the fetus, then decline hugely by birth
and thereafter until puberty? would you predict the loss is due to
apoptosis or necrosis?
Do PGCs in males only start to differentiate into spermatazoa at puberty?
They are only needed when oocytes are available to fertilise!
Which has a higher mutation rate before fertilisation?
Females. The mutation rate in male gametes is approx 5x higher than in
What % of sperm are aneuploid?
What % of oocytes are aneuploid?
What % of clinically recognised pregnancy loss results from chromosomal abnormalities?
Name a Mutation in early embryogenesis
What do you think are the possible outcomes if a very early embryo
was exposed to radiation (a mutagen) 3
• Teratogenesis (bnormalities of physiological development)
• Cancer when born
In general what do recessive mutations cause?
In general recessive mutations cause loss of function and often affect
biochemical pathways (not a rule!)