The Process of Cell

Growth & Division

1.1. How is the life cycle of a human and a single cell similar? How is the life cycle of a human and a single cell similar? 

2.2. How is the life cycle of a human and a single cell How is the life cycle of a human and a single cell different? different? 

3.3. Compare the life of cell to the clock – in 12 hours how long Compare the life of cell to the clock – in 12 hours how long does the cell spend actually dividing? does the cell spend actually dividing? 

4.4. Why do you think cells make a copy of their DNA before Why do you think cells make a copy of their DNA before they divide in half?they divide in half?

5. Is it easier to use string when it is spread Is it easier to use string when it is spread out or spooled up?out or spooled up?

6. Is it easier to transport string when it is 6. Is it easier to transport string when it is spread out or spooled up?spread out or spooled up?

7.7. What do we call DNA that is spread out?What do we call DNA that is spread out?

8.8. What do we call DNA that is coiled up?What do we call DNA that is coiled up?

9.9. Compare the string to DNA. Do you think it is easier for the cell Compare the string to DNA. Do you think it is easier for the cell to read (and use) the DNA when it is chromatin or chromosomes?to read (and use) the DNA when it is chromatin or chromosomes?

10.10.Compare the string to DNA. Do you think it is easier for the cell Compare the string to DNA. Do you think it is easier for the cell to pass the DNA onto future generations when it is chromatin or to pass the DNA onto future generations when it is chromatin or chromosomes? chromosomes? 

1. What are the two parts of the cell cycle?

2. Summarize what occurs during interphase?

3. What is the difference between mitosis and cytokinesis?

Growth and RegulationGrowth and Regulation

Growth and RegulationGrowth and Regulation4. What is G0?

What types of cells in your body are in G0?

Growth and RegulationGrowth and Regulation

5. Why do cells divide?

6. How many times can a normal cell divide?

7. What are the three ways normal growth is controlled? Explain each method.

anchorage dependenceanchorage dependence

density-dependent inhibitiondensity-dependent inhibition..

Proto-oncogenesProto-oncogenes

Growth and RegulationGrowth and Regulation8. What is a stem cell?

9. What is apoptosis?

10. Why is apoptosis so important to cells?

Growth and RegulationGrowth and Regulation

11. What is cancer?

12. What is a tumor?

Cancer is a disease caused by normal cells changing so that they grow in an uncontrolled way. The uncontrolled growth causes a lump called a tumor to form.

Growth and RegulationGrowth and Regulation

13.How many different types of cancer are there?

14.Why are there so many types of cancer?

15.List 5 different types of cancer that you have heard of

2009 Estimated US Cancer Cases*2009 Estimated US Cancer Cases*

*Excludes basal and squamous cell skin cancers and in situ carcinomas except urinary bladder.Source: American Cancer Society, 2009.

Men766,130

Women713,220

27% Breast

14% Lung & bronchus

10% Colon & rectum

6% Uterine corpus

4% Non-Hodgkin lymphoma

4% Melanoma of skin

4% Thyroid

3% Kidney & renal pelvis

3% Ovary

3% Pancreas

22% All Other Sites

Prostate 25%

Lung & bronchus 15%

Colon & rectum 10%

Urinary bladder 7%

Melanoma of skin 5%

Non-Hodgkin5% lymphoma

Kidney & renal pelvis 5%

Leukemia 3%

Oral cavity 3%

Pancreas 3%

All Other Sites 19%

US Mortality, 2006US Mortality, 2006

1. Heart Diseases 631,636 26.0 2. Cancer 559,888

23.1

3. Cerebrovascular diseases 137,119 5.7 4. Chronic lower respiratory diseases 124,583

5.1 5. Accidents (unintentional injuries) 121,599 5.0 6. Diabetes mellitus 72,449 3.0 7. Alzheimer disease 72,432 3.0 8. Influenza & pneumonia 56,326 2.3 9. Nephritis* 45,344 1.9

10. Septicemia 34,234 1.4 *Includes nephrotic syndrome and nephrosis.Source: US Mortality Data 2006, National Center for Health Statistics, Centers for Disease Control and Prevention, 2009.

Rank Cause of DeathNo. of deaths

% of all deaths

2009 Estimated US Cancer Deaths*2009 Estimated US Cancer Deaths*

ONS=Other nervous system.Source: American Cancer Society, 2009.

Men292,540

Women269,800

26% Lung & bronchus

15% Breast

9% Colon & rectum

6% Pancreas

5% Ovary

4% Non-Hodgkin lymphoma

3% Leukemia

3% Uterine corpus

2% Liver & intrahepaticbile duct

2% Brain/ONS

25% All other sites

Lung & bronchus 30%

Prostate 9%

Colon & rectum 9%

Pancreas 6%

Leukemia 4%

Liver & intrahepatic 4%bile duct

Esophagus 4%

Urinary bladder 3%

Non-Hodgkin 3% lymphoma

Kidney & renal pelvis 3%

All other sites 25%

Growth and RegulationGrowth and Regulation

16. How many times can cancer cells divide?

17. Why do scientists describe cancer cells as immortal? (two reasons)

18. Why can cancer cells spread while normal cells can not?

Like Begets LikeLike Begets Like Cell theory states that ‘cells come from Cell theory states that ‘cells come from

pre-existing cells’ (Rudolf Virchow 1858)pre-existing cells’ (Rudolf Virchow 1858) Some organisms create identical offspring – Some organisms create identical offspring –

through through asexual reproductionasexual reproduction

Some organisms create similar, but not Some organisms create similar, but not identical offspring – through identical offspring – through sexual sexual reproductionreproduction

Reproduction on the cellular level is called Reproduction on the cellular level is called cell divisioncell division..

Prokaryotic vs Eukaryotic Cells Remember that prokaryotic cells are:Remember that prokaryotic cells are:

Smaller than Eukaryotic CellsSmaller than Eukaryotic Cells

Simpler than Eukaryotic CellsSimpler than Eukaryotic Cells

It turns out that their DNA is also:It turns out that their DNA is also:

Shorter than Eukaryotic CellsShorter than Eukaryotic Cells

3,000 vs 300,000 genes long3,000 vs 300,000 genes long

Organized into only 1 strand, while Eukaryotic Organized into only 1 strand, while Eukaryotic cells its organized into manycells its organized into many

1 chromosome in a bacterium vs 46 in a 1 chromosome in a bacterium vs 46 in a humanhuman

A closer look at Eukaryotic DNA A closer look at Eukaryotic DNA throughout the life of the cell…throughout the life of the cell…

Day-to-day the DNA is coiled Day-to-day the DNA is coiled around histone proteins into around histone proteins into threads called threads called chromatin. chromatin.

Before dividing the DNA replicates Before dividing the DNA replicates (makes an identical copy of itself). (makes an identical copy of itself). The copy attaches to the original The copy attaches to the original forming somewhat of an X like forming somewhat of an X like structure. These are called structure. These are called chromatidschromatids..

When dividing the DNA coils even When dividing the DNA coils even further into short rods called further into short rods called chromosomeschromosomes. These are so . These are so dense they can be easily seen dense they can be easily seen through a microscope.through a microscope.

G1

S

G2

M phase

S phase

G1 phase

G2 phase

Growth (Interphase)Growth (Interphase) G1: Gap 1G1: Gap 1

Cell Cell growsgrows bigger and bigger and makes proteins needed makes proteins needed for life.for life.

S Phase: DNA SynthesisS Phase: DNA Synthesis During the S phase, the During the S phase, the

cell cell replicates its DNA.replicates its DNA. G2: Gap 2G2: Gap 2

Cell Cell grows even grows even bigger bigger and makes and makes proteins needed for two proteins needed for two cells!cells!

Cells can live their entire life growing. Cells can live their entire life growing. An example of this is An example of this is nerve cells in humans.nerve cells in humans. They never progress past this part of They never progress past this part of the cell cycle. the cell cycle.

Most cells, though, will divide (reproduce) at some point. Most cells, though, will divide (reproduce) at some point. Why would cells divide?Why would cells divide? Survival (they have become too big)Survival (they have become too big)

DNA overloadDNA overload Cell Transport overloadCell Transport overload

Benefit of the larger organismBenefit of the larger organism GrowGrow HealHeal

If a cell is going to divide it will continueIf a cell is going to divide it will continue through this sequence… through this sequence…

Not in notes – jot down what you think is important

Division of a Prokaryotic CellDivision of a Prokaryotic Cell

Called Called Binary Binary FissionFission

Chromosomes Chromosomes segregate (move segregate (move to opposite sides to opposite sides of the cell)of the cell)

Cell elongates and Cell elongates and dividesdivides

Division of an Eukaryotic CellDivision of an Eukaryotic Cell There are 2 stages to Division:There are 2 stages to Division:

Division of the DNA (MITOSIS)Division of the DNA (MITOSIS)

11. Prophase. Prophase

2. Prometaphase2. Prometaphase

3. Metaphase3. Metaphase

4. Anaphase4. Anaphase

5. Telophase5. Telophase

Division of the cytoplasm (CYTOKINESIS)Division of the cytoplasm (CYTOKINESIS)

ProphaseProphase Think Prepare - Think Prepare -

The DNA coils into The DNA coils into chromosomes.chromosomes.

Now visible by Now visible by microscopemicroscope

Centrioles Centrioles and and spindle spindle fibers fibers take their placestake their places

This is a picture of a cell in prophase.

PrometaphasePrometaphase Think Prepare for

Metaphase

Spindle fibers attach to kinetochore

Nuclear envelope disappears

MetaphaseMetaphase Think Middle - Think Middle -

Chromosomes line up at the center of the cell.

Chromosomes line up at metaphase plate equidistant between two poles.

This is a picture of a cell in metaphase.

AnaphaseAnaphase Think - apartThink - apart

Each centromere divides.

Motor proteins of kinetochores walk daughter chromosomes towards opposite poles

Sister chromatids separate and move apart.

This is a picture of a cell in anaphase.

Telophase/Telophase/CytokinesisCytokinesis Think - twoThink - two

Two nuclear Two nuclear membrane are membrane are formedformed

Chromosomes Chromosomes uncoil uncoil

Mitotic spindles Mitotic spindles disappeardisappear

Nucleoli reappearNucleoli reappear CytokinesisCytokinesis

Division of cytoplasmDivision of cytoplasm

This is a picture of a cell in telophase.

This is a picture of a cell in cytokinesis.

Videos of DivisionVideos of Division

http://www.johnkyrk.com/mitosis.html

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__mitosis_and_cytokinesis.html

http://www.hybridmedicalanimation.com/anim_mitosis.html

Cytokinesis Cytokinesis in Animal in Animal CellsCells

Cell’s membrane Cell’s membrane pinches pinches

inwardinward until the two sides until the two sides

touch resulting in two touch resulting in two

separate daughter cells.separate daughter cells.

Cytokinesis Cytokinesis in Plant in Plant CellsCellsCell’s membrane CAN NOT pinch Cell’s membrane CAN NOT pinch

inward because of the rigid cell inward because of the rigid cell

wall. Instead, awall. Instead, a cell plate cell plate

forms forms between the two nuclei between the two nuclei

and slowly grows into a new wall and slowly grows into a new wall

separating the two daughter cellsseparating the two daughter cells

S phase

G1 phase

G2 phase

Cell Cycle in Onion CellsCell Cycle in Onion Cells

interphase prophase metaphase

anaphase Telophase / cytokinesis

CancerCancer Cancer starts in one cell with one Cancer starts in one cell with one

mutation. This mutation causes the mutation. This mutation causes the cell to ‘cycle’ faster than it should.cell to ‘cycle’ faster than it should.

Over time – additional mutations Over time – additional mutations occur in the cell. These mutations occur in the cell. These mutations cause the cell to ‘cycle’ even faster – cause the cell to ‘cycle’ even faster – essentially the cell loses control!essentially the cell loses control!

CancerCancer Mutations can be – Mutations can be –

Inherited from your parentsInherited from your parents

RandomRandom

Caused by chemicals / environmental factors Caused by chemicals / environmental factors (carcinogens / mutagens) (carcinogens / mutagens)

Cigarette smokeCigarette smoke

Chewing tobaccoChewing tobacco

AsbestosAsbestos

UV lightUV light

X-raysX-rays

CancerCancer Mutations that cause cancer are specific – they must Mutations that cause cancer are specific – they must

affect the speed of the cell cycle and its survival!affect the speed of the cell cycle and its survival!

Proto-oncogenes mutate to oncogenes (fast forward)Proto-oncogenes mutate to oncogenes (fast forward)

Tumor suppressor genes mutate to stop working (breaks Tumor suppressor genes mutate to stop working (breaks fail)fail)

Angiogenesis genes are mutated to become active Angiogenesis genes are mutated to become active (unlimited food)(unlimited food)

P53 gene is mutated to stop working (immortal)P53 gene is mutated to stop working (immortal)

Various genes mutate to allow metastasis (cells spread)Various genes mutate to allow metastasis (cells spread)

Most cancers are caused by 5-10 mutations. Cancer Most cancers are caused by 5-10 mutations. Cancer is a disease of multiple mutations in one cell. is a disease of multiple mutations in one cell.

Magic BulletsMagic Bullets MitchMitch

Leukemia – white blood cellsLeukemia – white blood cells

Symptoms – back painSymptoms – back pain

Treatment – Glevic (magic bullet that blocks an oncogene)Treatment – Glevic (magic bullet that blocks an oncogene)

JeffJeff

Kidney Cancer that spread to abdonmenKidney Cancer that spread to abdonmen

Treatments – Anti-Veg-F (magic bullet that blocks Treatments – Anti-Veg-F (magic bullet that blocks angiogenesis)angiogenesis)

The End