Transcript Chromosomes and Cell Division!

Chromosomes and Cell Division!
Cell division: Mitosis vs Meiosis
There are two types of cell division and each has
its own product
Mitosis: makes exact copies of cell, used for repair, replacement, growth and development.
Good when you need to make an exact copy of cells
Happens in ALL body cells (autosomes)
Meiosis: makes copies of the cell that are haploid (1/2 of the chromosomes) so that each paent
has equal genetic input into offspring
Good for when you need genetic variability
Happens in sex cells (haploid + haploid = diploid)
Vocab
Chromatin: Unorganized, unwrapped DNA
Chromosome: rod-shaped structures made of DNA wrapped around proteins
Histone: the protein that DNA wraps itself around before cell division
Chromatids: one of the two strands of a chromosome that becomes visible
during mitosis/meiosis
Centromere: region of chromosome that holds sister chromatids together
Autosome: body cells, non sex cells, exact copies of parent cells
Sex cells: sperm and egg. Combine to create offspring (zygote)
Homologous chromosomes: chromosomes that have the same sequence of
genes, pair up during meiosis
Sex chromosome: two chromosomes that determine the sex of an individual
XX= Female
XY= Male
Haploid and Diploid
Haploid (1N): any cell that has only one set of unpaired chromosomes (sex cells)
Diploid (2N): any cell that has both sets of chromosomes (all non sex cells)
Haploid Egg + Haploid sperm = diploid Zygote
Humans have 23 pairs of chromosomes
How many total chromosomes?
Karyotype: a micrograph of the array of chromosomes visible in a cell during
metaphase.
Can be used to identify a species
Al species have a specific number of chromosomes
46 chromosomes
Extension: Oliver the Humanzee
What kinds of test were done to determine whether
Oliver was a human-chimpanzee hybrid?
47 Chromosome hybrid karyotype?
Cell Cycle/Cell Division
Cell Cycle
Chromatin
Cell division: Mitosis
Mitosis: Stop action animation
Your task: Create a stop-motion animation of
mitosis.
-Must be AT LEAST 6-10 Slides
-Must have each step (prophase, metaphase, anaphase, telophase)
Share with me via Google mail
Meiosis
Mitosis vs Meiosis, which one is better?
Please indicate the circumstances that would make one better
than the other. Support your decision using terminology and
other information you have learned.
Independent Assortment
Over 64 billion different combinations!!!
Crossing over
Swappin’ DNA
Extensions…
So, why is crossing over important?
What would happen over time without genetic
crossover?
How/why did sexual reproduction develop
through time? What are the
benefits/drawbacks?
Makin’Meiosis
• Your Task: Now is YOUR opportunity to demonstrate your understanding
of mitosis and meiosis and then compare and contrast them. You have
options:
• Option1: Simulating Meiosis Flip Books.
• Please use your understanding of meiosis, the information you have
learned in class, and Lab 29 to construct a flip book that shows the steps
of meiosis in stunning accuracy and lifelike motion!!!, Think: Cartoon
• Option 2: Wildcard
• Please use your understanding of meiosis, the information you have
learned in class, and the general idea described in Lab 11 to create your
own model of meiosis. Things to consider using: chromosomes in
karyotype lab, a white board, markers and colored pencils. The sky is the
limit, be creative…
• How you will be graded:
Mendel and his Dang Genetics
What did Mendel teach us about genetics, and what
are “we” doing with that knowledge?
Punnett square
He grew some crazy looking peas