UNIT 3: CELL DIVISION

(MITOSIS)

Starr et al., 2013. Chapter 8 and 11 p. 124-125 and 164-171, Edulink and learning guide notes

CHROMOSOMESChapter 8 p. 124-125

Chromosomes form when the chromatin network in the nucleus of the cell, coil up, shortens and thickens.

Each organism has a specific amount of chromosomes.

All humans have 46 chromosomes. These chromosomes are arranged in identical pairs

called homologous chromosome pairs – Therefore humans have 23 homologous pairs of

chromosomes. These chromosomes is only visible during cell division

processes.   One chromosome consist of 2 chromatids and one

centromere that attach the chromatids together. Each chromatid consist of genes which in turn consist

of DNA.

CHROMOSOMESTRUCTURE

X and Y chromosomes: gonosomes/sex-chromosomes

Colored bands represents different genes

THE PHASES OF THE CELL CYCLECHAPTER 11 P. 164

The cell cycle includes the following phases:

Interphase (include G1- , S- [DNA synthesis] and G2 phase)

Mitosis Cytokinesis Growth

The result is 2 identical cells.

Why is Mitosis important?

Allow an organism to grow.

Repairs damaged cells/tissue.

Replace dead cells/tissue.

Reproduction in some simple organisms.

Where does Mitosis take place?

In all somatic cells (include all body cells and excludes the sex cells – sperm/egg cells)

The process of Mitosis.

CONSIST OF A FEW PHASES: INTERPHASE PROPHASE METAPHASE ANAPHASE TELOPHASE

BioFlix: Mitosis

INTERPHASE

Cell builds up enough energy for division process.

DNA replication occurs Cell look normal, like before division

PROPHASE

Nuclear envelope and nucleolus disappear.

Chromatin become more tightly coiled, and condenses into individual chromosomes. Chromosomes arrange randomly in the cell.

Centrioli move to opposite poles, with spindle fibers stretching between them.

METAPHASE

The centrioli reached the opposite poles with the spindle fibers in between.

The chromosomes arrange randomly on the equator, each single chromosome attaching to a separate spindle fiber by means of the centromere.

ANAPHASE

The spindle fibers pull tight. The centromers attaching the

chromatids of the chromosomes split in half.

Daughter chromosomes move to opposite poles.

EARLY TELOPHASE – KARYOKINESIS (DIVISION OF

NUCLEUS Daughter chromosomes

reach poles. Nuclear envelope surrounds

chromosomes. Nucleolus reappear at each

pole. Chromosomes become less

condense forming chromatin.

Two identical nuclei has been formed

LATE TELOPHASE – CYTOKINESIS (DIVISION OF THE CYTOPLASM)

Invagination of the cytoplasm and plasma membrane occurs. (Cleavage furrow forms in animal cells and a cytoplasmic plate forms in plant cells)

Continues until the cell in divided into 2 separate cells. (Identical to one another and to the original cell)

MITOSIS PROCESS

CANCER Chapter 11 p.170-171

Cancer is caused by the loss of cell cycle controls in cancer cells.

Cancer cells usually continue to divide well beyond a single layer, forming a clump of overlapping cells called a tumor.

Malignant tumors invade surrounding tissues and can metastasize exporting cancer cells to other parts of the body, where they may form secondary tumors.

They do not exhibit anchorage dependence or density dependent inhibition.

Ovarian cancer cells Breast tumor

Ovarian cancer cells dividing

RESEARCH PROJECTUNIT 3: CELL DIVISION – CANCER

OCCURANCE OF CANCER IN HUMANS

 

 

Task

Divide into groups of 8. Design a research project for

students using the theme Cancer. Complete the actual research project

that you have designed in detail as an example of what you expect from a student.

Marks will be allocated according to the following criteria:

Design Originality of the project 10 Planning of the design 10 Assessment you will be using 10 Assessment criteria you will be using 10 Design construction and set up. 10 Clarity of task 10

Complete example of research project

Cover page 10 Index 10 Content – scientific and true – no plagiarism 10 Reference indicated in content 10 Summary of references provided in Bibliography. 10 Includes diagrams/ graphs/ tables/ statistics 10 Includes own opinion and ideas. 10 Neatness 10 Overall impression (Did you do what the project required

you to do) 10

Total : 150

HAND IN 10 MAY 2013