Today’s Lecture Summary: Cellular reproduction Binary fissionBinary fission MitosisMitosis MeiosisMeiosis Reading Assignment: Chapter 8

Learning Outcomes: By the end of today’s lecture, you should be able to: - explain the difference between binary fission, mitosis and meiosis - list and describe the steps of mitosis and meiosis - list the processes by which cell division is regulated and explain what happens to cells that don’t respond to these regulatory mechanisms - explain the processes that lead to genetic variation during meiosis - explain the chromosomal problems that can occur during meiosis

Cell division:

Cell division functions: - Growth & development - Tissue renewal - Reproduction

Binary fission occurs in prokaryotic cells:

Binary fission:

Human karyotype: ordered display of an individual’s chromosomes

Female karyotype: Male karyotype:

Genes: nucleotide sequences of DNA.

 The location of the gene on the chromosome is called the locus (plural: loci).  Different forms of a gene are called alleles.

Homologous chromosomes are the same in size, shape and genetic information.

Mitosis:

Mitosis (cont.):

Mitosis in Animal Cell (LM):

Mitosis in Plant Cell:

Normal cells vs. Cancer cells:

Cancerous breast tumor:

The asexual reproduction of a hydra:

Each couple has one daughter and one son. Which child belongs to which couple?

couple 2couple 1couple 1couple 2

Meiosis: sexual reproduction

Meiosis occurs in two phases: Meiosis I: Meiosis II:

 A cell with two copies of a chromosome is diploid (2N).  A cell with one copy of a chromosome is haploid (N).

Independent assortment during meiosis:

Crossing over during meiosis:

Down karyotype (Trisomy 21):

Down syndrome:

Alteration of chromosome number due to non-disjunction during meiosis I:

Non-disjunction during meiosis II:

Fertilization after non-disjunction:

Abnormal numbers of sex chromosomes:

Klinefelter syndrome (XXY): Turner syndrome (XO):

Alterations of chromosome structure:

Alterations of chromosome structure (cont.):

Translocation associated with chronic myelogenous leukemia (CML):

Today’s Lecture Summary: Cellular reproduction Binary fissionBinary fission MitosisMitosis MeiosisMeiosis Reading Assignment: Chapter 8

Check for understanding…

1. Starting w/ a single cell, a series of 5 mitosis events would yield a total of how many cells? 2. A chemical prevents the production of DNA; what step in mitosis would be prevented? 3. a) A cell w/ 46 chromosomes undergoes mitosis to produce daughter cells w/ _____ chromosomes b) A cell w/ 46 chromosomes undergoes meiosis to produce daughter cells w/ _____ chromosomes 4. How is reciprocal translocation different from normal crossing over?

Complete the table below: