Exam: Genetics Flashcards
What are the gs cell theory states
All living things are composed of one or more cells
All cells come from or existing cells
Cells are the simplest unit of living organisms
Difference between chromatin, chromatid, centromere
Chromatin - DNA
Chromatid - half a chromosome
Centreomete - holding chromatids together
What are the three stages of interphase
G1- majour phase of growth
S - DNA replication
G2 - secondary growth phase
Mitosis: describe PMAT
Prophase: everything is getting ready to split
Metaphase: all chromosomes go in the middle
Anaphase: split into sister chromatids
Telophase: Chromosomes reach opposite poles of cell and unravel
What is cytokinesis
Takes place after telophase, equal division of cytoplasm and organelles among daughter cells and forms a cleavage furrow.
How many chromosomes do we have in our body
46 (22 diploids, 2 sex)
What is meiosis
Basically mitosis but interkinase only happens once and first it’s diploids then turns into haploids. 4 divisions instead of 2
Purpose of mitosis
To grow, Regenerate and maintenance. This takes place throughout life in the somatic cells
Purpose of meiosis
To produce gametes with each of of parents genetics .Takes place during puberty in the gamete cells.
What is abnormal meiosis
Chances in number or structure
What is deletion in a chromosome
A piece of chromosome is lost
What is duplication in chromosome
Section of a chromosome appears two or more times in a row
What is Inversion in a chromosome
Segment of DNA in a chromosome flips upside down, no information is lost
What is translocation in a chromosome
Non homologous chromosomes cross over
What is nondisjunction
Improper separation or a fail to separate during meiosis
When does non disjunction happens
Anaphase I or Anaphase II.
What are the two results on nondisjunction
Monosomy= single pair
Trisomy= three pairs
What is Trisomy 21
Down syndrome
What is Trisomy 18
Edward syndrome,
Trisomy 13
Patan syndrome
What is XXY
Kilnefelter (can’t produce sperm)
What is XYY
Jacobs (taller than average)
What is XXX
Triple X (tall and thin with irregular mentrual cycle)
What is XO
Turner (short statue, webbed feet, sexually underdeveloped)
What is a ultrasound
Non invasive Visual image of body through sound waves
What is a multiple marker screen
Non invasive Blood test and ultrasound at 15-20 weeks. Check mothers blood for tube defects. Tests 21 and 18
What is Aminocentesis
Inavise needle to uteri’s to extract amniotic fluid. 1% chance of miscarriage. Tests everything.
What is chorionic villi sampling
Invasive sampling of placenta to take out chorionic villi. 1% miscarriage. Tests for everything
What is a genotype
The genetic combination of a gene
What is a phenotype
Things seen visually on a person
What is true breeding
When parents give homologous traits to the child
