Mitosis
In what two stages of mitosis can cytokinesis begin?
Anaphase, Telophase
Meiosis I produces what type of cell? How many?
2 Haploid cells
1) Centrosomes move apart & 2) spindle forms and microtubules begin to capture chromosomes
(BONUS: chromosomes condense)
What fails to separate in non disjunction for Mitosis, Meiosis I, and Meiosis II?
Meiosis I: homologous pairs
Meiosis II: sister chromatids
What does "-pro" mean?
Before
What phase has the spindle checkpoint? What does it do?
Metaphase, ensures sister chromatids will split evenly before continuing into next phase
In Meiosis I, what part of the chromosome gets disconnected?
The homologous pairs
True or false: crossing over does not take place in Meiosis II and the centrosomes move together in prophase II instead of apart
False: Crossing over does not take place but centrosomes move apart
What are the four types of chromosomal rearrangements?
Duplication, deletion, inversion, translocation
*Reciprocal and non reciprocal translocation
Why is the process of crossing over so important in meiosis? (Bonus if you can name which phase)
It enables genetic diversity! (It occurs in Prophase I.)
In Anaphase, what carries chromosomes and other microtubules along?
motor proteins
What is the difference between synaptonemal complex and the chiasmata?
The synaptonemal complex holds the homologous pairs together so crossing over can take place.
Chiasmata is the cross shaped structures where where homologous pairs link together.
How many chromosomes line up at the metaphase plate in Metaphase II in humans?
23 chromosomes (BUT 46 chromatids)
What is the term for when there are the correct amount of chromosomes present?
Euploid
True or false: Sperm and egg cells perform meiosis to perform new sperm/egg
FALSE: Actually, sperm cells and egg cells don't perform meiosis at all! It is a primordial germ cell that divides to make sperm and egg cells.
For cytokinesis in animal cells, what is actin?
Actin is a protein that makes filaments that aids in separating the cells
True or False: In telophase I, all organisms develop a nuclear envelope and their chromosomes are decondensed
False: only some organisms do, other skip this step
In what two phases of meiosis II are there 46 chromosomes and 46 chromatids?
In what two phases of Meiosis II are there 23 chromosomes and 46 chromatids?
Prophase II & Metaphase II
Anaphase II & Telophase II
when human embryos are missing a copy of an autosome (monosomy), there are not enough ________ and _____________ being made
proteins, gene products
What kind of division is meiosis?
a) Multiplication division
b) Reduction division
c) Intermediary division
d) Meiosis is not a division -- it is multiplication!
B (but d is not entirely wrong...)
What is the number of chromosomes and chromatids in all stages of Mitosis and after cytokinesis?
Prophase: 46 chromosomes, 92 chromatids
Metaphase: 46 chromosomes, 92 chromatids
Anaphase: 92 chromosomes, 92 chromatids
Telophase: 92 chromosomes, 92 chromatids
after Cytokinesis: 46 chromosomes, 46 chromatids
How many chromosomes and chromatids are there at the end of Meiosis I?
23 chromosomes
46 chromatids
What is the difference between Meiosis II and Mitosis?
Honestly...they are pretty similar -- Meiosis II can be thought of as a sort of mitosis that completes the division of Meiosis I into four haploid daughter cells. BUT, the biggest difference is that meiosis II starts with the division of TWO daughter cells with 46 chromatids each to separate the chromosomes AND chromatids evenly into 4 haploid daughter cells (23 chromosomes and 23 chromatids in each cell).
trisomy; thyroid or heart diseases, broad skull, large tongue, developmental delays
Mary has a monosomy of chromosome 16. Tom has a trisomy of chromosome 21. Who is most likely to not survive till adulthood?
Unfortunately, because Mary has an autosomal aneuploidy, she will likely not make it to birth.