Cell Division Flashcards
What does a chromosome refer to?
Condensed DNA
What does a chromatid refer to?
Decondensed DNA
What does DNA wrap around when condensed?
Histones
What does homologous mean?
Refers to the way chromosomes are paired. Same size, same traits.
What’s an autosome
A basic chromosome.
What happens in G1?
Cells grow
Cells undergo life function
What happens in S?
Cells double their DNA
What happens in G2?
Cell prepares for division
What is karyokinesis?
Nucleus (DNA) Movement
What is cytokinesis?
Cell Movement
Describe the events of Prophase.
DNA will condense
Nucleus breaks apart
2 centrosomes move to the poles
Describe the events of metaphase.
The chromosomes line up ON the equatorial plate.
Spindle fibers attach to the kinetochore of the centromere.
Describe the events of anaphase.
Start of cytokinesis
Start of karyokinesis
DNA begins to decondense
Nucleus begins to form again
Describe the events of telophase.
Nucleus now almost formed
Cells now almost separate
What are the effects of chemotherapy?
Interrupts cell cycle
Effects all cells
What are the effects of radiation therapy?
Cancer cells are more susceptible to radiation
Nausea, hair loss, lose elasticity
Describe the events of Prophase I?
DNA will condense
Nucleus breaks apart
2 centrosomes move to the poles
Recombination also takes place.
What is recombination?
A random exchange of genes between chromosomes. This process increases the genetic variation amongst the gametes produced and can only occur during prophase I.
Describe the events of metaphase I.
Chromosomes line up on either side of the equatorial plate
Sister chromosomes stick together
Describe the events of anaphase I.
Chromosomes are segregated
Homologs are pulled to separate sides of the cell
DNA starts to decondense
Describe the events of telophase I.
Nucleus now almost formed
Cells now almost separate
What is Meiotic interphase?
A pause
No metabolism
No DNA replication
Nothing like interphase in cell cycle
Describe the events of prophase II.
DNA will condense
Sister Chromosomes join
Nucleus breaks apart
2 centrosomes move to the poles
Describe the events of metaphase II.
The chromosomes line up ON the equatorial plate.
Spindle fibers attach to the kinetochore of the centromere.
Describe the events of anaphase II.
Start of cytokinesis
Start of karyokinesis
DNA begins to decondense
Nucleus begins to form again
Describe the events of telophase II.
Nucleus now almost formed
Cells now almost separate
What is a nondisjunction?
A failure to properly segregate chromosomes during meiosis.
In what division is a nondisjunction most common?
Meiosis I
What is (2n + 1)?
Trisomy #
What is (2n - 1)?
Monosomy #
What is down syndrome?
Trisomy 21
What is the syndrome of down syndrome?
Abnormality in face Pronounced epicanthal folds Wide-set eyes Pronounced forehead Enlarged Tongue Shorter Mental retardation Short lifespan Delayed puberty
What is Turner’s Syndrome?
Monosomy 23
What is the syndrome of Turner’s Syndrome?
Considered female Shorter than normal Can have mental retardation Generally, can live on own Broad neck Odd ear placement Sterile without hormone therapy
What is Klinefelter’s?
One type of Trisomy 23: XXY
What are the effects of Klinefelter’s?
Breasts Grow
Hips Widen
What are the effects of Trisomic females?
No effect on woman
Can have effect on her children
What are the effects of Trisomic males?
Slightly taller than average.
Describe Alternation of Generation.
A diploid adult undergoes meiosis to produce haploid offspring. These haploid offsprings grow to be adults. Then, they undergo mitosis to create gametes that will combine and create diploid offspring.
