ch. 10 vocabulary due today!

48
Chapter 10 Meiosis Textbook pages 270 - 276

Upload: nickan

Post on 23-Feb-2016

37 views

Category:

Documents


0 download

DESCRIPTION

Ch. 10 Vocabulary Due Today!. Chapter 10 Meiosis. Textbook pages 270 - 276. Reproduction. Reproduction - process of producing offspring . Some offspring are produced by two parents . Some offspring are produced by just one parent . - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: Ch. 10 Vocabulary Due Today!

Chapter 10 Meiosis

Textbook pages 270 - 276

Page 2: Ch. 10 Vocabulary Due Today!

Reproduction• Reproduction - process of producing

offspring.• Some offspring are produced by two parents.• Some offspring are produced by just one

parent.• Whether an organism is identical or similar to

its parent is determined by the way the organism reproduces.

Page 3: Ch. 10 Vocabulary Due Today!

Asexual Reproduction• Production of identical offspring:

– Mitosis– Binary Fission– Budding

Today were going to talk about sexual reproduction at the cellular level.

Page 4: Ch. 10 Vocabulary Due Today!

Sexual Reproduction• Practiced by most eukaryotic organisms• In sexual reproduction, two parents give

genetic material to produce offspring that are genetically different from their parents.

• Each parent produces gametes (reproductive cell); sperm and eggs.

• A gamete from one parent fuses with a gamete from the other parent to form a zygote.

• This process is called fertilization.

Page 5: Ch. 10 Vocabulary Due Today!

Germ Cells & Somatic Cells1. Germ cells (gametes) are cells that are

specialized for sexual reproduction (sperm & egg).

2. Somatic cells are all other body cells. They DO NOT participate in sexual reproduction.

Page 6: Ch. 10 Vocabulary Due Today!

All cells contain chromosomes. There are two types of chromosomes found in the nucleus of cells:

1. autosomes2. sex chromosomes

Your body cells contain 23 pairs of homologous chromosomes:

• 23 chromosomes from your mom, and

• 23 chromosomes from your dad

CHROMOSOMES:

Page 7: Ch. 10 Vocabulary Due Today!

NEW Term! • Homologous chromosomes are

chromosomes that make up a pair; one from each parent– Are the same length– Have the same genes

Page 8: Ch. 10 Vocabulary Due Today!

Your body cells contain 23 pairs of homologous chromosomes:

For each homologous pair, one chromosome comes from mom and one comes from dad.

Page 9: Ch. 10 Vocabulary Due Today!
Page 10: Ch. 10 Vocabulary Due Today!

Chromosome pairs 1-22 are autosomes.

The 23rd pair are the sex chromosomes: X and Y which determine gender:

XX =XY =

femalemale

LOOK AT THE KARYOTYPE BELOW:

Page 11: Ch. 10 Vocabulary Due Today!

Haploid vs. Diploid• Cells that are diploid (somatic cells) have two

sets of chromosomes (2n)• Cells that are haploid (gametes) have one set

of chromosomes (n)

Page 12: Ch. 10 Vocabulary Due Today!

Body Cells- somatic cells- diploid (2n)

Diploid (2n) cells – have two copies of every chromosome

- half the chromosomes come from each parent

Gametes- sex cells (sperm and egg)- have DNA that can be passed to offspring- haploid (n)

Haploid (n) cells – have one copy of each chromosome- gametes have 22 autosomes and 1 sex chromosome

Page 13: Ch. 10 Vocabulary Due Today!

Key Terms • Diploid refers to complete

chromosome sets in a cell (or 2N)– N= the number of chromosomes in a

gamete (sex cell)– N chromosomes from the female

parent + N chromosomes from the male parent= 2N

– For humans, 2N = 46

Page 14: Ch. 10 Vocabulary Due Today!

Key Terms • Haploid refers to single

chromosomes in a cell (or N)– One-half of the 2N set (the maternal

N or the paternal N)– Gametes (i.e. sperm, egg sex cells) are

haploid cells– For humans, N = 23

Page 15: Ch. 10 Vocabulary Due Today!

Bottom Line

• diploid means there are the full number of chromosomes in cells

• haploid means that there are half the number of chromosomes in cells

Page 16: Ch. 10 Vocabulary Due Today!
Page 17: Ch. 10 Vocabulary Due Today!

MITOSIS AND MEIOSIS

Page 18: Ch. 10 Vocabulary Due Today!

Mitosis and meiosis are types of nuclear division that make different types of cells.

Mitosis- occurs in somatic cells- makes more diploid cells

Meiosis- occurs in sex cells- Makes 4 haploid cells from diploid cells- produces gametes

Make a Venn diagram to compare andContrast Mitosis and Meiosis!

Page 19: Ch. 10 Vocabulary Due Today!

MEIOSIS10-1

Making gametes…

http://waynesword.palomar.edu/lmexer2a.htm

Page 20: Ch. 10 Vocabulary Due Today!

Cells go through two rounds of division in meiosis:

Meiosis reduces the chromosome number and creates genetic diversity.

homologous chromosomes

sisterchromatids

sisterchromatids

• Meiosis I and Meiosis II - each round has four phases

• Meiosis I – pairs of homologous chromosomes separate

• Meiosis II – sister chromatids divide

Page 21: Ch. 10 Vocabulary Due Today!

Meiosis Interphase Occurs….

• Replication of DNA• Chromatin condenses

Sounds familiar right???

Page 22: Ch. 10 Vocabulary Due Today!

Meiosis I• Occurs after DNA has been replicated in interphase

• Divides homologous chromosomes in four phases: prophase I metaphase I anaphase I telophase I

• After cytokinesis, two cells are produced with one homologous chromosome in each

Page 23: Ch. 10 Vocabulary Due Today!

PROPHASE I • Homologous

chromosomes pair up• Crossing over occurs• Nuclear envelope

breaks down• Spindles form

Page 24: Ch. 10 Vocabulary Due Today!

What is Crossing Over?• Chromosomal segments (genetic information)

are exchanged between a pair of homologous chromosomes

Crossing Over Creates Genetic diversity

Page 25: Ch. 10 Vocabulary Due Today!

Which set of chromatids illustrates the result of a single crossover of the homologous chromosomes?

Page 26: Ch. 10 Vocabulary Due Today!

METAPHASE I

• Spindle fibers attach to the centromeres

• Homologous Chromosomes Line up at the equator

• chromosome pairs line up randomly in cell

Page 27: Ch. 10 Vocabulary Due Today!

ANAPHASE I

• Homologous chromosomes separate and move to the opposite poles of the cell

Page 28: Ch. 10 Vocabulary Due Today!

TELOPHASE I

• The cell divides• The result is two. 2

Haploid daughter cells with exchanged genetic information

• The daughter cells are not genetically identical

**During Telophase I Cytokinesis occurs at the same time!!**

Page 29: Ch. 10 Vocabulary Due Today!

Review Meiosis I

Interphase I Prophase I Metaphase I Anaphase I

.

Telophase I

Page 30: Ch. 10 Vocabulary Due Today!

Meiosis II

• Meiosis II divides sister chromatids in four phases: prophase II metaphase II anaphase II telophase II

• After cytokinesis, four new cells are produced, each with half the chromosome number (haploid)

Page 31: Ch. 10 Vocabulary Due Today!

• Nucleus breaks up• Spindles form and

attach to centromere

Page 32: Ch. 10 Vocabulary Due Today!

• Sister chromatids randomly align at middle of cell

Page 33: Ch. 10 Vocabulary Due Today!

• Sister chromatids separate

• Chromosomes move to opposite poles of cell

Page 34: Ch. 10 Vocabulary Due Today!

Page 35: Ch. 10 Vocabulary Due Today!

• Cells divide• 4 haploid

daughter cells result

• Each cell is genetically different

Page 36: Ch. 10 Vocabulary Due Today!

Review Meiosis II

Prophase II Metaphase II Anaphase II Telophase II.

Page 37: Ch. 10 Vocabulary Due Today!

Meiosis Animation

Page 38: Ch. 10 Vocabulary Due Today!

• During meiosis, the egg gets most of the contents• The other cells form polar bodies

• Eggs contribute DNA, cytoplasm and organelles to an embryo

• Sperm become streamlined and mobile with the addition of flagella• Sperm primarily contribute DNA to an embryo

Haploid cells develop into mature gametes:

Gametogenesis - the production of gametes - differs between females and males

Page 39: Ch. 10 Vocabulary Due Today!

Sources of Variations and Differences1. Crossing over

2. Random assortment of chromosomes

3. Fertilization

• occurs during prophase I• homologous chromosomes swap pieces• this chromosome swapping creates variations

• chromosome pairs line up randomly in cell• when the pairs separate, this creates cells with genetic variations

• which sperm gets to the egg first?? • it is random and can create variations in offspring

Page 40: Ch. 10 Vocabulary Due Today!

MitosisMeiosis

Page 41: Ch. 10 Vocabulary Due Today!
Page 42: Ch. 10 Vocabulary Due Today!
Page 43: Ch. 10 Vocabulary Due Today!

Warm-up

• What is made during Mitosis???

• What is made during Meiosis??

• What are the phases of Meiosis?

Page 44: Ch. 10 Vocabulary Due Today!
Page 45: Ch. 10 Vocabulary Due Today!

Videos that show side by side view

• http://highered.mcgraw-hill.com• http://www.pbs.org/wgbh/nova/miracle/divi_

flash.html

Page 46: Ch. 10 Vocabulary Due Today!

WHY MEIOSIS?• MITOSIS – RESULTS IN GENETICALLY

IDENTICAL OFFSPRING – INCLUDING THE # CHROMOSOMES

• WHAT WOULD HAPPEN IF THE EGG AND SPERM HAD THE SAME # OF CHROMOSOMES AS THE BODY CELLS?

EGG = 46 CHROMOSOMES SPERM = 46 CHROM.

ZYGOTE = 46 + 46 = 92 CHROMOSOMES = NOT HUMAN

Page 47: Ch. 10 Vocabulary Due Today!

Mitosis Animation

Page 48: Ch. 10 Vocabulary Due Today!

Meiosis Animation