Chapter 8

Chapter 8: 

Chapter 8 Cellular Reproduction: Cells from Cells

Slide 2: 

© 2010 Pearson Education, Inc. Asexual Reproduction FUNCTIONS OF CELL DIVISION Sea stars LM Amoeba African Violet Figure 8.1b

Binary Fission (asexual reproduction): 

© 2010 Pearson Education, Inc. Binary Fission (asexual reproduction)

Onion cell: 

Onion cell

Why do we need Mitosis?: 

© 2010 Pearson Education, Inc. Why do we need Mitosis? Cell division = Mitosis Replaces damaged or lost cells Permits growth How do we make sure that the cells are the same as the parent?

Some vocabulary we’ll need…: 

Some vocabulary we’ll need… Cell division - process by which cells reproduce Chromosomes - cell parts that determine what traits a living thing will have Chromatid - one strand of DNA; after replication, a chromosome is made up of two identical chromatids Daughter cells - new cells produced by cell division Cytokinesis – a division of the cytoplasm of one parent cell into 2 daughter cells

Slide 7: 

© 2010 Pearson Education, Inc.

Slide 8: 

© 2010 Pearson Education, Inc.

Mitosis: 

Mitosis

Slide 10: 

© 2010 Pearson Education, Inc.

Interphase: 

© 2010 Pearson Education, Inc. I nterphase Interesting things happen! Cell preparing to divide This is the phase of mitosis where the cell performs its normal activities for life. DNA is in the chromatin state (kind of like spaghetti)

Slide 12: 

© 2010 Pearson Education, Inc.

Slide 13: 

© 2010 Pearson Education, Inc.

Slide 14: 

© 2010 Pearson Education, Inc. Prophase Chromosome pair up ! Chromosomes thicken and shorten -become visible -2 chromatids joined by a centromere Centrioles move to the opposite sides of the nucleus Nucleolus disappears Nuclear membrane disintegrate

Slide 15: 

© 2010 Pearson Education, Inc.

Slide 16: 

© 2010 Pearson Education, Inc.

Slide 17: 

© 2010 Pearson Education, Inc. M etaphase Chromosomes meet in the middle ! Chromosomes arrange at equator of cell Become attached to spindle fibers by centromeres Homologous chromosomes do not associate

Slide 18: 

© 2010 Pearson Education, Inc.

Slide 19: 

© 2010 Pearson Education, Inc. A naphase Sister chromatids get pulled apart Spindle fibres contract pulling chromatids to the opposite poles of the cell

Slide 20: 

© 2010 Pearson Education, Inc.

Slide 21: 

© 2010 Pearson Education, Inc. T elophase Now there are two! Chromosomes uncoil Spindle fibres disintegrate Centrioles replicate Nucleur membrane forms Cell divides

Slide 22: 

© 2010 Pearson Education, Inc.

Slide 23: 

© 2010 Pearson Education, Inc.

Slide 24: 

© 2010 Pearson Education, Inc.

Slide 25: 

© 2010 Pearson Education, Inc. I P M A T

How can we remember the stages of mitosis?: 

How can we remember the stages of mitosis? I nterphase P rophase M etaphase A naphase T elophase IPMAT

Slide 27: 

© 2010 Pearson Education, Inc. plant cytokinesis

Slide 28: 

© 2010 Pearson Education, Inc.

Mitosis produces identical offspring (2N---2N) 2N = Diploid Number: 

© 2010 Pearson Education, Inc. Mitosis produces identical offspring (2N---2N) 2N = Diploid Number

Slide 30: 

© 2010 Pearson Education, Inc. Mitosis and Meiosis Mitosis: -division of somatic (body) cells Meiosis -division of gametes (sex cells)

Slide 31: 

© 2010 Pearson Education, Inc. Sexual reproduction: Uses meiosis – there are half the number of chromosomes Produces offspring that contain a unique combination of genes from the parents Why do we need to decrease the chromosomes in the sperm and egg? At fertilization the male and female each will provide ½ of the chromosomes – so the offspring has genes from both parents

US: 

© 2010 Pearson Education, Inc. US We as humans have 46 chromosomes in every cell When we make a baby it needs 46 chromosomes Thus, meiosis makes the sperm with 23 and the egg with 23 chromosomes which is called n=haploid number 23 + 23 = 46 You get 1 chromosome from mom and 1 from Dad There are 2 copies and these are called homologous chromosomes

Homologous Chromosomes: 

© 2010 Pearson Education, Inc. Homologous Chromosomes

Slide 34: 

© 2010 Pearson Education, Inc.