13.1 Genetic Fundamentals Flashcards
What does it mean that DNA strands run antiparallel within a molecule?
Run in opposite directions
What are some clinical implications of chromosomal abnormalities?
- Cancer
- Miscarriage
Cytogenetics
Study of chromosomes
Do all genetic changes that cause miscarriage have implications in the parents?
No; some changes have no effect on someone’s health, but can result in miscarriage. This makes them difficult to test for/detect.
What are the two arms of a chromosome?
P (Small “petite”), and Q (Large)
Define aneuploidy
Missing or extra chromosomes
What are some kinds of aneuploidy?
- Triploidy
- Autosomal trisomies
- Monosomy/trisomy of sex chromosome
How many chromosomes in triploidy?
69 :)
Which three autosomal trisomies have a reasonable chance of surviving to full term?
- Down Syndrome (21)
- Edward’s Syndrome (18)
- Patau Syndrome (13)
Why are autosomal trimosies bad?
Changes dosage “balance” between genes. For some genes, this is fine, but for some, it is disastrous for development.
What is non-disjunction?
Failure of chromosome segregation (meiosis 1) or separation (meiosis 2)
What is turner Syndrome?
Only one X chromosome is present
What is Klinefelter syndrome?
Trisomy of X chromosome (XXY)
Which autosomal monosomies are compatible with life?
None of them.
Why are sex chromosome autosomies more tolerated than autsomal autosomies?
X aneuploidy: X inactivation
Y aneuploidy: very few genes on Y chromosome
