Monday 11/9/2015Agenda: Cell Cycle and Division!

Activity: Finish Mitosis Packet

Activity: Cell Cycle Quest!!

Homework:

No Homework Tonight!

https://www.youtube.com/watch?v=ZEwddr9ho-4

Tuesday 11/10/2015Agenda: Cell Cycle and Division!

Activity: Meiosis Reading Guide

Homework:

Meiosis Reading Guide due Thursday/Friday 11/12-11/13/2015 for 40 Points

NO SCHOOL ON WEDNESDAY!

Meiosis Reading Guide • You are to annotate each paragraph 4 times

(there are 4 total paragraphs)

• Answer questions 1-18 on the worksheet

• This is due TODAY for 40 Points!!

Thursday/Friday 11/12-11/13/2015

Agenda: Cell Cycle and Division!

Notes: Meiosis and Meiosis Terminology

Activity: Meiosis Foldable

Activity: Amoeba Sisters with Worksheet

Homework:

No Homework!

MEIOSISQ2 WK3 D2

Meiosis

Meiosis is the type of cell division by which germ cells (eggs and sperm) are

produced.

One parent cell produces four daughter cells.

Daughter cells have half the number of chromosomes found in the parent cell

MeiosisDuring meiosis, DNA replicates

once, but the nucleus divides twice.

There are 2 parts to Meiosis:1. Meiosis 12. Meiosis 2

The 4 new daughter cells have variation of the parent DNA; this is genetic variation

Meiosis Terminology• Karyotype: Arranging of chromosomes from largest

to smallest; pairing up the homologous chromosomes• Autosomes: All non-sex chromosomes; (#1-22 for

humans)• Sex Chromosomes: Chromosomes that determine

the sex of an organism (#23 for humans)• Set (n): # of different chromosomes. REMEMBER:

Haploid = 1set, Diploid= 2 sets

Karyotype of a human• Is this person male or

female?

• How many sex chromosomes are present?

• How many autosome chromosomes are present?

• How many homologous pairs of chromosomes are present?

Background on Meiosis• Meiosis involves 2 divisions of the nucleus

• Meiosis 1 & Meiosis 2

Meiosis STARTS with HOMOLOGOUS CHROMOSOMES

Homologous Chromosomes: They are similar in shape, size & genetic content

Meiosis 1: 1st Division of Meiosis• Prophase I: Chromosomes

condense, nuclear envelope breaks, homologous chromosomes pair at ends.

• ***Cross-Over: Part of chromatid on 1 homologous chromosome exchanges with the other chromosome***

DRAW ME THIS IS

GENETIC VARIATION

Meiosis 1: 1st Division of Meiosis• Metaphase I: Homologous chromosomes move to center of the cell by the spindle fibers.

• Anaphase I: Homologous chromosomes separate and move to opposite poles, BUT sister chromatids stay together. A set of chromosomes moves to each pole

• Telophase I: The spindle fibers disappear, cells begin to cleave; still, two sets of chromosomes are at opposite poles

Meiosis 1

End of Meiosis I

• Once Meiosis I is complete, cytokinesis occurs and the cell splits into 2 haploid cells. These 2 cells enter Meiosis II

Meiosis II• Prophase II: A new spindle forms around the

chromosomes (no longer HOMOLOGOUS CHROMOSOMES)

• Metaphase II: Chromosomes line up at center & spindle fibers attach to centromere

• Anaphase II: Centromeres split, chromatids move to opposite poles of cell

• Telophase II: Nuclear envelope forms around each set of chromosomes & spindles retracts, cell begins cytokinesis

Result of Meiosis II• 4 HAPLOID cells form as a result of Meiosis II

• Haploid = cell containing 1 set of chromosomes

Meiosis II: 2nd division of Meiosis

Prophase II

http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html

Metaphase II

http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html

Telophase II

http://everyschool.org/u/logan/cellreproductionx/rogersa/research/meiosis.html

Differences in Mitosis & Meiosis

• Mitosis• Asexual• Cell divides once• Two daughter cells form• Genetic informationS is

identical

• Meiosis• Sexual• Cell divides twice• Four haploid daughter cells

form• Genetic information is

different