10. KEY CONCEPTS
The cell cycle is divided into two main stages: interphase and the mitotic phase.
During interphase cells grow in size and replicate their DNA
Mitosis is the process by which cells distribute their replicated DNA to two daughter cells.
The mitotic phase consists of five stages: prophase, metaphase, anaphase, telophase and cytokinesis.
Mitosis is the means of reproduction in unicellular organisms that undergo asexual reproduction.
Mitosis is required for growth and repair in multicellular organisms.
Cancer is caused by carcinogens and is treated through surgery, radiation and chemotherapy.
11. Assignment: Due date: 21 May 2017
Names of the mitotic phases.
Draw simple descriptive diagrams showing the chromosome changes in mitotic
phases.
The difference between animal and plant cells in cytokinesis.
The purpose of mitosis.
Causes and treatment of cancer.
14. Interphase
This stage is divided into three parts: G1, G2 and S phases.
G1 phase:
occurs just after the two daughter cells have split and the cells have only one copy of
their DNA.
Cells in this stage synthesise proteins and increase in size.
15. S phase:
Is the stage during which DNA replication occurs.
The cell makes an identical copy of each of its chromosomes.
Chromosomes are found inside the nucleus of the cell and consist of long
strands.
DNA that contain the genetic information of the cell.
16. G2 phase:
The cell will start to replicate its organelles in preparation for mitosis.
17. Mitotic Phase (M phase)
The mitotic phase (M phase) is composed of two stages: mitosis and
cytokinesis.
In mitosis; chromosomes in the cell nucleus separate into two
identical sets in two nuclei.
Cytokinesis: the cytoplasm, organelles and cell membrane split into
two IDENTICAL cells.
19. PROPHASE (P)
• Nuclear and nuclear membrane
disappears.
• Chromatids joins to form a chromosome
attached by a centromere.
• Centrioles move to opposite poles.
• Centrioles give rise to the spindle
fibres which form between the poles.
20. METAPHASE
• Chromosomes line up on the equator of the cell.
• The chromosomes appear in a straight line across the middle of the cell.
• Each chromosome is attached to the spindle fibres by its centromere.
21. ANAPHASE
• The chromatids are pulled to opposite poles of the cell by the shortening the spindle fibres.
• Chromatids are now called daughter chromosomes.
27. TYPES OF CANCER
Breast cancer
Lung cancer
Oesophageal cancer
Leukaemia (blood cancer)
Melanoma (skin cancer)
Cancer can affect almost any tissue in the body. A list of
some common cancers includes:
28. TYPES OF CANCER CELLS
BENIGN TUMORS; tumours cannot spread
to other tissues.
Malignant tumors: they are able to invade
tissues and spread to other parts of the
body.
29. HOW DOES CANCER CELLS DIFFER WITH
NORMAL CELLS?
Cancer cells don’t listen to signals to stop growing.
Cancer cells grow new blood vessels
Cancer cells spread around the body:
30. CAUSES OF CANCER
Cancer is caused by agents called carcinogens. Carcinogens cause cancer by damaging
DNA which can no longer code for the important regulatory functions of the cell cycle.
CARCINOGENS SUCH AS:
Cigarette smoke
Radiation
X-rays
UV light
food additives
Several dangerous chemicals
31. PREVENTION OF CANCER
Avoid smoking.
Avoid alcohol.
Healthy diet.
Regular physical activity.
Sun protection.
Regular screenings.