Genetics and Inheritance Flashcards
What two things can genetic screening be used for?
Confirming a diagnosis
Identifying carriers
What is Amniocentesis?
Inserting a needle into amniotic fluid to collect cells from embryo
What is Chorionic Villus sampling?
Collecting a small sample of placental tissue removed from the wall of the abdomen or the vagina
When is Amniocentesis carried out?
15-17 weeks pregnancy
When is Chorionic Villus carried out?
8-12 weeks pregnancy
What is the risk of miscarriage for Chorionic Villus?
0.5 - 1%
What is the risk of miscarriage for Amniocentesis?
1 -2%
What is in vivo fertilisation?
Calculating risk of conceiving child with disorder
If 50% or above, proceed with pregnancy then carry out pre-natal tests
What is pre-natal testing?
Amniocentesis
Chorionic Villus
What is in vitro fertilisation
Fertilising egg in petri dish with sperm [obtained from masturbation]
Remove cell from embryo when it has 8-16 cells [causes no harm to embryo]
Test the cell for the genetic disorder
What are the disadvantages of in vitro fertilisation?
Expensive
Fairly unreliable: False positives/False negatives
What is the role of mRNA in protein synthesis?
Genetic copy of the DNA template strand that needs to be made into a protein Leaves nucleus (because it's smaller than DNA) and travels to cytoplasm to bind to ribosome for translation
What is the role of tRNA in protein synthesis?
Binds to specific amino acid and transports to mRNA on ribosome
Binds to mRNA in codon/anticodon interaction
Holds amino acid in place so peptide bonds can form between adjacent acids
What is a mutation?
An alteration in DNA which can give rise to a different protein
What does ‘recessive’ mean?
The version of an allele that will only be expressed in the absence of the dominant allele.
