Cell Reproduction 1

Cell DivisionCell cycle and Mitosis: Chapter 10

Not responsible for:Figure 10.3 & related text on proteins that control chromosome separation and septum formation 10.7 Control of the cell cycle. This section covers more of the molecular details than you will be responsible for; however, we will cover the concept of cell cycle checkpoints, oncogenes and tumor suppressor genes as related to cancer

Question

Cell Reproduction 2

Why is it important to understand the processes of cell replication?

Diversity & evolution

Cancer

Birth defects

Reproductive biotechnologyBasal cell carcinoma

Question

eukaryotic

prokaryotic

Cell Reproduction 3

What are the characteristics of cell division in Prokaryotes?

Simpler structure

No nucleus

Single chromosome

Binary fission

Cell Reproduction 4

Chromosome structure in eukaryotes

Structure of chromosomes

… in nondividing cells

… in dividing cells

Supercoiling

Question

Cell Reproduction 5

What are homologous chromosomes?

Homologous Chromosomes: -- one derived from each parent -- possess same genes, although genetic

information in gene may be different= “alleles”

How many homologous chromosomes do different organisms possess?

humans: 2N = 46 N= haploid # of chromosomesgoldfish: 2N=94crayfish: 2N = 200

Autosomes vs sex chromosomes

Question

Cell Reproduction 6

What is the cell cycle?

What are the stages and events?Mitosis

G1

G0

S

G2

Question

Cell Reproduction 7

What are the steps of mitosis?

When does mitosis occur?

What are the stages of mitosis?

prophase

prometaphase

metaphase

anaphase

telophase

Cytokinesis

Animal cell mitosis

Cell Reproduction 8

What happens during prophase?

Chromosome condensation

Spindle apparatus

Centrosomes

What happens during prometaphase?

Nuclear membrane

Spindle attachment

Kinetochores

McGraw-Hill mitosis

Question

kinetochore

Cell Reproduction 9

…Metaphase

…AnaphaseFilaments ‘pull’ and “push’

Question

Cell Reproduction 10

Telophase and cytokinesis

What happens during telophase?

What causes cytokinesis to occur?

Does cell division in plants and animals differ?

Plant cell mitosis

Cell Reproduction 11

Homework assignment:

5 points: due next class

For a cell where 2N=6, draw a series of diagrams showing the chromosomes moving through the stages of mitosis.

In one of the diagrams clearly label:-- a pair of homologous chromosomes-- two sister chromatids-- spindle fibers-- centrosomes and -- position of a kinetochore

Label all stages (prophase, prometaphase, metaphase, anaphase and telophase)

Make diagrams large, clear and neat

Advanced artistry is not required, but drawings of supercoiled chromosomes

and spindle fibers must show reasonable effort to accurately

represent these structures.

not x

Question

Cell Reproduction 12

What is the difference between a ‘tumor’ and ‘cancer’?

Benign vs malignant tumors

Metatasis

Primary vs secondary tumors

The angiogenesis problem

Why are tumors and cancer so harmful?

Angiogenesis and Metastasis

Cell Reproduction 13

What causes a tumor to grow?

Loss of control of cell division

What are Protooncogenes?-- proteins they code for act as molecular ‘switches’ for cell division

Oncogene = mutated protooncogene-- ‘switch’ is locked in

the ‘on’ condition

What are Tumor Suppressor Genes?-- proteins they code for stop abnormal cells from reproducing-- damaged DNA-- cell cycle ‘checkpoints’

Mutated tumor suppressor gene-- “Stop” signals do not work

Other mutations cause tumorous cells to spread as a cancer

= “Metastasis”

Cell Reproduction 14

Stem cells and cloning

What are stem cells?

Embyonic vs somatic

How is cloning performed?

Mitotic Waltz