Why does a cell divide? PowerPoint Presentation

Why does a cell divide? PowerPoint Presentation

2017-04-13 57K 57 0 0

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Efficiency . 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. ID: 536979

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Presentations text content in Why does a cell divide?

Slide1

Why does a cell divide?

Efficiency Smaller the cell = quicker it can workTransport of SubstancesCellular communicationRatio of surface area to volume

Slide2

Other reasons for cellular division

GrowthReplace damaged cells

Slide3

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

Interphase – cell grows, replicates DNA

Mitosis – nucleus and nuclear material divide

Cytokinesis – cytoplasm divides

Slide4

Slide5

3 Stages of Interphase

Gap 1 (G

1

)

normal functions

Synthesis (S)

Cell copies DNA

Gap 2 (G

2

)

Cell prepares for mitosis

Slide6

Mitosis

Cell’s DNA separates

Creates 2

identical

daughter cells

Same Number of Chromosomes

4 Stages – Prophase, Metaphase, Anaphase,

Telophase

Slide7

1. Prophase

Chromatin condenses into chromosomes X – shapedConsist of two chromatids – identical copies of DNAChromatids are connected at a centromere

Slide8

1. Prophase

Nuclear membrane disappears Spindle apparatus appearsSpindle fibers, centrioles, and aster fibers

Slide9

2. Metaphase

Chromatids Line up at center of cell

Slide10

3. Anaphase

Chromatids pull apart

Slide11

4. Telophase

Chromosomes arrive at the polesChromosomes unwindTwo nuclear membranes begin to formSpindle apparatus disappears

Slide12

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

Slide13

Slide14

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

http://www.sumanasinc.com/webcontent/animations/content/mitosis.html

Slide15

https://

www.youtube.com/watch?v=L0k-enzoeOM

Slide16

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

Slide17

The Cell Cycle and Cancer

Benign

= not cancerous

Do

not invade neighboring tissue or spread

Malignant

= cancerous

Readily

invade neighboring tissues

May

also detach and lodge in distant places – metastasis

Slide18

Slide19

p. 181

4

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

Slide20

How does it happen?

Oncogenes

are activated

Normal function: cell growth, gene

transcription

Tumor

suppressor

genes are inactivated

Normal function: DNA repair, cell cycle control, cell

death

Slide21

Tumor suppressors

“Guardian(s) of the genome”

Often involved in maintaining genomic integrity (DNA repair, chromosome segregation)

Mutations in

tumor

suppressor genes lead to the “

mutator

phenotype”—mutation rates increase

Often the 1

st

mutation in a developing

cancer

P53 and

Rb

Slide22

Causes of Cancer

Mutation

:

change in genetic

makeup

Any agent that causes cancer is called a

carcinogen

and is described as

carcinogenic

Infection

Viruses (EBV, hepatitis B, papilloma)

Bacteria (Helicobacter

)

Slide23

Lifestyle Risks

SmokingDiet high fat and low in fruits and vegetablesLack of exercise Unprotected exposure to the sun, (UV) raysObesityStressJobs – exposed to chemicals, etcRadiation

Slide24

Environmental Risks

Second hand smokePCB’sAir pollutionIndustrial pollutionChemical exposurestar from cigarettessome foods

Slide25

Inherited Risks

Less than 15% of cancers are inheritedSome families are more susceptible to getting certain cancersYou can’t inherit cancer its just that you maybe more susceptible to getting it

Slide26

Treatment

Chemotherapy

treatment

uses

medicine to weaken and destroy cancer cells in the

body

affects

the whole

body

Radiation therapy (also called radiotherapy)

high-energy rays are used to damage cancer cells and stop them from growing and dividing

local treatment; it affects cancer cells only in the treated

area

Slide27

Cancer Prevention

Healthy lifestyle

Exercise

and proper breathing

Balanced diet

Complete

rest and sleep

Water

Eating Fruit

Slide28

Explain what happens in each step of mitosis.

Agenda forReview mitosis (video?)Mitosis Cell Lab

Slide29

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

Finish lab

Finish worksheets

Start cancer notes

Slide30

What is cancer?

Agenda for

Cancer Notes

Go over worksheets and lab

Cancer worksheet


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