cell reproduction cell reproduction. qsr #6?? 1. _________ is the process by which cells divide to...
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QSR #6??QSR #6?? 1. _________ is the process by which 1. _________ is the process by which
cells divide to make more cells.cells divide to make more cells. 2. Your _______ cells divide most 2. Your _______ cells divide most
often while your ______ cells almost often while your ______ cells almost never divide.never divide.
3. In eukaryotic cells, chromosomes 3. In eukaryotic cells, chromosomes are found in the _______, but in are found in the _______, but in prokaryotic cells they are found in prokaryotic cells they are found in the ____________.the ____________.
Cell ReproductionCell Reproduction
Cell division is the process by which Cell division is the process by which cells reproducecells reproduce
ChromosomesChromosomes: rod-shaped : rod-shaped structures made of DNA and proteinsstructures made of DNA and proteins
ChromatidsChromatids
One single strand One single strand of the chromosomeof the chromosome
Held together by a Held together by a centromerecentromere
Cell CycleCell Cycle
Sequence of growth and division of a Sequence of growth and division of a cell – the life cycle of a cellcell – the life cycle of a cell• Apoptosis: cellular deathApoptosis: cellular death
• Figure2.14 – In the embryo, fingers and Figure2.14 – In the embryo, fingers and toes are carved from webbed structures. toes are carved from webbed structures. In syndactyly, normal apoptosis, fails to In syndactyly, normal apoptosis, fails to carve the digits and webbing occurscarve the digits and webbing occurs
A. InterphaseA. Interphase
1. Resting phase because it is not dividing 1. Resting phase because it is not dividing but it can be getting ready for divisionbut it can be getting ready for division
2. performing everyday, normal functions2. performing everyday, normal functions 3. Can be divided into 3 stages3. Can be divided into 3 stages
• G1G1• SS• G2G2
B. G1 phase (Gap 1)B. G1 phase (Gap 1)
1.Growth phase1.Growth phase 2.Grows rapidly2.Grows rapidly 3.Carries out routine functions3.Carries out routine functions
D. G2 phase (Gap 2)D. G2 phase (Gap 2)
1.Growth and Prep for Mitosis1.Growth and Prep for Mitosis 2.organelles replicates2.organelles replicates (Doubling everything to prepare for (Doubling everything to prepare for
mitosis)mitosis)
Cells divide at different rates:Cells divide at different rates: Cell type Cell type Approximate life Approximate life
spanspan• Skin cellsSkin cells 2 weeks2 weeks• Red blood cellRed blood cell 4 months4 months• Liver cell Liver cell 300-500 days300-500 days• Intestinal cellsIntestinal cells 4-5 days4-5 days• Muscle/other cellsMuscle/other cells 16 years16 years• Brain cellsBrain cells maybe nevermaybe never• ++++++++++++++++++++++++++++++++++++++++++++++++
MitosisMitosis Process in which the nucleus of a cell Process in which the nucleus of a cell
divides into two nuclei, each with the divides into two nuclei, each with the same kind of chromosomessame kind of chromosomes
InterphaseInterphase
Chromosomes are replicatedChromosomes are replicated Chromosomes appear as threadlike Chromosomes appear as threadlike
coils (chromatin) at the start, but coils (chromatin) at the start, but each chromosome and its copy each chromosome and its copy (sister chromosome) change to sister (sister chromosome) change to sister chromatids at the end of this phasechromatids at the end of this phase• ***Remember: sister chromatids are ***Remember: sister chromatids are
held together by a held together by a centromere.centromere.
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The Stages of the cell cycle
ProphaseProphase
Mitosis begins in this phaseMitosis begins in this phase Centrioles (poles) appear and begin to Centrioles (poles) appear and begin to
move to opposite ends of cell.move to opposite ends of cell. Spindle fibers form between the polesSpindle fibers form between the poles CHROMATIN condenses (coils up) into CHROMATIN condenses (coils up) into
CHROMOSOMES CHROMOSOMES The nuclear envelope starts to break up The nuclear envelope starts to break up the Nucleolus disappearsthe Nucleolus disappears
MetaphaseMetaphase
Chromatids or pairs of chromosomes Chromatids or pairs of chromosomes attach to the spindle fibersattach to the spindle fibers
the Chromosomes line up at the the Chromosomes line up at the “Middle” of the cell“Middle” of the cell
AnaphaseAnaphase
Chromatids (or pairs of Chromatids (or pairs of chromosomes) separate and begin to chromosomes) separate and begin to move to opposite ends of the cell move to opposite ends of the cell
Centromere divides Centromere divides
TelophaseTelophase
Two new nuclei formTwo new nuclei form Chromosomes appear as chromatin Chromosomes appear as chromatin
(threads rather than rods)(threads rather than rods) Nuclear envelope & nucleolus Nuclear envelope & nucleolus
reformsreforms
CytokinesisCytokinesis
Division of the cytoplasmDivision of the cytoplasm• Cell membrane moves inward to create Cell membrane moves inward to create
two two daughterdaughter cells cells – each with its own – each with its own nucleus, identical chromosomes, and a nucleus, identical chromosomes, and a total of 46 chromosomes eachtotal of 46 chromosomes each
• MicroscopeMicroscope: fish blastodisc (white fish) : fish blastodisc (white fish) mitosis, onion tip mitosis, ascaris mitosis mitosis, onion tip mitosis, ascaris mitosis (parasite – intestinal roundworm)(parasite – intestinal roundworm)
Mitosis, Mitosis Mitosis, Mitosis Amelia ArellanoAmelia Arellano
Mitosis, Mitosis divided into four Mitosis, Mitosis divided into four stages. Prophase, Metaphase, stages. Prophase, Metaphase, Anaphase, and Telephase. Prophase Anaphase, and Telephase. Prophase Prophase, Nucleus breaks down Prophase, Nucleus breaks down Metaphase, Metaphase Chromosomes Metaphase, Metaphase Chromosomes line up in the center. Anaphase, line up in the center. Anaphase, Anaphase chromosomes moving to Anaphase chromosomes moving to the opposite poles. Telophase, the opposite poles. Telophase, Telophase envelop forms And the Telophase envelop forms And the spindle fiber begin to disappear spindle fiber begin to disappear
Results of MitosisResults of Mitosis
CellsCells TissuesTissues
• musclemuscle OrgansOrgans
• stomachstomach Organ systemOrgan system
• Digestive systemDigestive system OrganismOrganism
Stem cellsStem cells
Undifferentiated/ blank cellUndifferentiated/ blank cell Can be developed into a variety of Can be developed into a variety of
different cellsdifferent cells
Ex: embryonic stem cell can give rise to Ex: embryonic stem cell can give rise to almost any cellalmost any cell
Ex: Adult stem cells can give rise to Ex: Adult stem cells can give rise to related cellsrelated cells
Why is stem cell research so important? Why is stem cell research so important?
Cell DifferentiationCell Differentiation
Cells become specialized to perform Cells become specialized to perform specific functions…liver cells, skin specific functions…liver cells, skin cells, etc.cells, etc.
Is based on location in an embryoIs based on location in an embryo• Outer– skin, brain, spinal cordOuter– skin, brain, spinal cord• Middle– bones, muscles, kidneysMiddle– bones, muscles, kidneys• Inner– internal organs (pancreas, Inner– internal organs (pancreas,
stomach, etc.)stomach, etc.)
Asexual ReproductionAsexual Reproduction Creation of an offspring with only one parentCreation of an offspring with only one parent Ex: Binary Fission Ex: Binary Fission
• a form of mitosisa form of mitosis• – – division into 2 equal parts division into 2 equal parts
**** (done in prokaryotic cells) ******** (done in prokaryotic cells) **** Genetically identical to parentGenetically identical to parent Ex: bacteria, some plants (stem cutting), sea starEx: bacteria, some plants (stem cutting), sea star
How is this different from sexual reproduction? How is this different from sexual reproduction? ###################### ######################
QSR #8QSR #8 1. Fill in the blanks to make the correct order: 1. Fill in the blanks to make the correct order:
cells, ______, ______, cells, ______, ______, systems, _________.systems, _________. 2. _____ cells are undifferentiated meaning they 2. _____ cells are undifferentiated meaning they
____________ and can become other types of cells.____________ and can become other types of cells. 3. Cell differentiation depends on the location of 3. Cell differentiation depends on the location of
the cells inside the ______. If they are in the outer the cells inside the ______. If they are in the outer layer they can become ________, middle layer they can become ________, middle layer________, inner layer________.layer________, inner layer________.
4. How are embryonic stem cells different from 4. How are embryonic stem cells different from adult stem cells?adult stem cells?
CancerCancer
CancerCancer• Uncontrolled Mitosis/Cell DivisionUncontrolled Mitosis/Cell Division• Enzymes (proteins) monitor a cell’s Enzymes (proteins) monitor a cell’s
progress from phase to phaseprogress from phase to phase
CancerCancer
Caused by damaged genesCaused by damaged genes• Cancerous (malignant) cells form Cancerous (malignant) cells form
masses of tissuemasses of tissue TumorsTumors
• Deprive normal cells of nutrientsDeprive normal cells of nutrients• Spread throughout the body Spread throughout the body
Metastasis (cancer cells break away, get into Metastasis (cancer cells break away, get into blood stream, and spread)blood stream, and spread)
Cause of CancersCause of Cancers 1. Environmental factors (Carcinogens) – damage 1. Environmental factors (Carcinogens) – damage
genesgenes• Cigarette smoke, air pollutants, UV radiationCigarette smoke, air pollutants, UV radiation
2. Genetic2. Genetic 3. Viral Infections3. Viral Infections 4. Different types of cancers in different parts of 4. Different types of cancers in different parts of the worldthe world
• Breast cancerBreast cancer High USHigh US Low JapanLow Japan
• Stomach cancerStomach cancer High in ChinaHigh in China Low in USLow in US
Cancer PreventionCancer Prevention
Healthy Exercise and NO TOBACCO Healthy Exercise and NO TOBACCO products!!!!products!!!!
Vitamins and mineralVitamins and mineral• YellowYellow• Orange Orange • AA• CC• EE• CaCa