Why do cells divide? Agenda for Friday Dec 19 th 1.Go over test 2.Mitosis notes & video 3.Mitosis worksheet Grades on wall

Why does a cell divide? Too large to work efficiently – Smaller the cell = quicker it can work Transport of Substances Cellular communication – Ratio of surface area to volume

Other reasons for cellular division Growth Replace damaged cells

The Cell Cycle Cell reaches max size it stops growing or divides – Cells reproduce by growing and dividing = cell cycle 3 main stages of cell cycle 1.Interphase – cell grows, replicates DNA 2.Mitosis – nucleus and nuclear material divide 3.Cytokinesis – cytoplasm divides

3 Stages of Interphase Gap 1 (G 1 ) Right after cell divides, normal functions, prepares to replicate DNA Synthesis (S) Cell copies DNA (contains genetic material) – Chromatin is the relaxed form of DNA – Chromosomes are the condensed form of DNA Gap 2 (G 2 ) Cell prepares for mitosis

Mitosis Cell’s DNA separates –C–Creates 2 identical daughter cells –S–Same DNA –S–Same Number of Chromosomes in each cell 4 Stages – Prophase, Metaphase, Anaphase, Telophase

1. Prophase Chromatin condenses into chromosomes – X – shaped – Consist of two chromatids – identical copies of DNA – Chromatids are connected at a centromere

1. Prophase Nuclear membrane disappears Spindle apparatus appears – Spindle fibers, centrioles, and aster fibers – Helps move chromosomes

2. Metaphase Chromatids Line up at center of cell

3. Anaphase Chromatids pull apart

4. Telophase Chromosomes arrive at the poles Chromosomes unwind (back to chromatin) Two nuclear membranes begin to form Spindle apparatus disappears

Cytokinesis Divides cytoplasm Animal Cells – Microfilaments constrict/pinch the cytoplasm Plant Cells – Cell plate forms between two daughter nuclei – Cell walls then form on either side of cell plate

Explain what happens in each step of mitosis. Agenda for Monday Jan. 5 th 1.Review mitosis (video) 2.Go over HW 3.Mitosis Cell Lab

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If a cell has 150 chromosomes how many daughter cells are created at the end of mitosis? How many chromosomes are in each cell? Agenda for Tuesday Jan 6 th 1. Finish mitosis onion cell lab

hill.com/sites/ /student_view0/chapter2/animation__mitosis_and_cytok inesis.html

What is cancer? Agenda for Thursday Jan 8 th 1.Cancer Notes 2.Cancer worksheet

Cancer Vocab Cancer – uncontrolled growth and spread of abnormal cells Neoplasm – new growth of tissue that serves no physiological function Tumor – clumping of neoplasmic cells Malignant - cancerous Benign - noncancerous Biopsy –examination of cell development

Skin Cancer The ABCD’s of melanoma (skin cancer): – Asymmetry: one half is not like the other – Border: the edges are jagged or irregular – Color: the color is varied, tan, red, black ect – Diameter: the diameter is larger than 8mm (the top of a pencil eraser ABCD

Cancer Uncontrolled cell division Tumors begin with a single cell that reproduces by mitosis – Cells in tumors divide continuously Metastasis: Process in which cells are invasive and move to other sites in the body

How does it happen? Two classes of genes: Oncogenes and tumor suppressor genes – Proto-oncogenes: control cell division – Tumor suppressor genes turn off cell division

p Cell division Mitosis 3 DNA repair G2 1 Cell grows, doubles in size G1 S 2 Chromosome duplication G2/M checkpoint G1/S checkpoint Stepped Art Checkpoints in the cell cycle regulate cell division

The Cell Cycle and Cancer Neoplasm- abnormal growth of cells Benign neoplasms are not cancerous – Encapsulated; Do not invade neighboring tissue or spread Malignant neoplasms are cancerous – Not encapsulated; Readily invade neighboring tissues – May also detach and lodge in distant places – metastasis

Stages of Cancer 4 stages, – 1 = not so bad – 4 = really bad Stage I – localized to one part of the body Stage II - locally advanced Stage III - also locally advanced Stage IV - often metastasized, or spread

Causes of Cancer Mutation: change in genetic makeup A factor which brings about a mutation is called a mutagen. Any agent that causes cancer is called a carcinogen and is described as carcinogenic.

What Causes Cancer? Lifestyle Environment Family History

Lifestyle Risks Smoking Diet high fat and low in fruits and vegetables Lack of exercise Unprotected exposure to the sun, (UV) rays Obesity

Environmental Risks Second hand smoke Air pollution Industrial pollution Chemical exposures – tar from cigarettes – some foods

Inherited Risks Less than 15% of cancers are inherited Gene mutations are linked to some inherited cancers Cancers that may be caused by inherited gene mutations are: – Colon cancer – Breast cancer – Ovarian – Prostate cancer – Skin cancer Some families are more susceptible to getting certain cancers. – Remember you can’t inherit cancer its just that you maybe more susceptible to getting it.

Stress There is connection between stress, immune system and cancer, that is changing the direction of research – it now appears that cancer cells make proteins that actually tell the immune system to let them alone and even to help them grow.

Other ways Many forms of cancer related to: – Physical surroundings – Personal behavior – Or both At least 50% of all cancer can be attributed to some type of environmental factor

Treatment Chemotherapy treatment uses medicine to weaken and destroy cancer cells in the body, including cells at the original cancer site and any cancer cells that may have spread to another part of the body. a systemic therapy, which means it affects the whole body by going through the bloodstream.

Treatment Radiation therapy (also called radiotherapy) high-energy rays are used to damage cancer cells and stop them from growing and dividing. A specialist in radiation therapy is called a radiation oncologist Like surgery, radiation therapy is a local treatment; it affects cancer cells only in the treated area

Cancer Prevention Healthy lifestyle Exercise and proper breathing Balanced diet Complete rest and sleep Water Eating Fruit

lab

How does one go about getting cancer (name 2 ways)? Agenda for Friday Jan 9 th 1.Quiz 2.Cancer lab

Mitosis Foldable Go to Page 243 Follow those directions

Homework Page 253 – 257 Questions 1 – 7 on page 257