Cell Structures and Their Cell Structures and Their FunctionsFunctions

Cell StructureCell Structure

Highly OrganizedHighly Organized

. Specialized structures called . Specialized structures called organelles in a jelly like organelles in a jelly like substance called cytoplasmsubstance called cytoplasm

Amount and type of organelles is Amount and type of organelles is related to functionrelated to function

Functions of the CellFunctions of the Cell

Basic Unit of Life -smallest part that still retains Basic Unit of Life -smallest part that still retains characteristics of lifecharacteristics of life

Protection And Support – cells secrete substances Protection And Support – cells secrete substances that provide that provide

Movement- occurs because of molecules that are Movement- occurs because of molecules that are located in specific cells e.g. muscle cells located in specific cells e.g. muscle cells

Communication-cells receive information that Communication-cells receive information that allow them to communicate with each other eg allow them to communicate with each other eg nerves cell tells muscle cells to contractnerves cell tells muscle cells to contract

Cell metabolism and energy release- all the Cell metabolism and energy release- all the chemical reactions that occur within the cellchemical reactions that occur within the cell

Inheritance – each cell contains a copy of the Inheritance – each cell contains a copy of the genetic information of the individualgenetic information of the individual

The OrganellesThe Organelles

The NucleusThe Nucleus Nucleoli and RibosomesNucleoli and Ribosomes Rough and Smooth Endoplasmic ReticulumRough and Smooth Endoplasmic Reticulum The Golgi ApparatusThe Golgi Apparatus Secretory VesiclesSecretory Vesicles Lysosomes and PeroxiisomesLysosomes and Peroxiisomes MitochondriaMitochondria CytoskeletonCytoskeleton Centrioles Centrioles Cilia, Flagella and MicrovilliCilia, Flagella and Microvilli The Cell MembraneThe Cell Membrane

Cell MembraneCell Membrane

Phospholipid BilayerPhospholipid Bilayer Protection and TransportProtection and Transport Types of Transport Types of Transport Active ( requires ATP) Active ( requires ATP) Passive Passive

NucleusNucleus

Contains the genetic material of cell (DNA)Contains the genetic material of cell (DNA) Located near the center of the cellLocated near the center of the cell Some cells lose their nucleus as they mature, Some cells lose their nucleus as they mature,

some have more than one nucleus bone cellssome have more than one nucleus bone cells Nuclear envelop (outer and inner membranes Nuclear envelop (outer and inner membranes

and nuclear pores)and nuclear pores) Contains loosely coiled fibers called chromatin Contains loosely coiled fibers called chromatin

consisting of DNA When a cell divides the consisting of DNA When a cell divides the chromatin becomes more tightly coiled to form chromatin becomes more tightly coiled to form the 23 pairs of chromosomesthe 23 pairs of chromosomes

Nucleoli and RibosomesNucleoli and Ribosomes

Nucleoli- are rounded dense well Nucleoli- are rounded dense well defined nuclear bodies with no defined nuclear bodies with no surrounding membranes surrounding membranes

Ribosome's- are the organelles where Ribosome's- are the organelles where proteins are produced proteins are produced

-may be free -may be free -attached to the endoplasmic reticulum-attached to the endoplasmic reticulum

-made in the nucleus-made in the nucleus

Smooth and Rough Smooth and Rough Endoplasmic ReticulumEndoplasmic Reticulum

The ER is a series of membranes The ER is a series of membranes forming sacs and tubules that forming sacs and tubules that extends from the outer nuclear extends from the outer nuclear membrane into the cytoplasmmembrane into the cytoplasm

Rough ER – has ribosomes Rough ER – has ribosomes attached indicting that it is attached indicting that it is synthesizing large amounts of synthesizing large amounts of protein for export from the cellprotein for export from the cell

Protein SynthesisProtein Synthesis

Transcription Transcription

TranslationTranslation

RNARNA

mRNAmRNA t RNAt RNA r RNAr RNA

The Golgi ApparatusThe Golgi Apparatus

Golgi Apparatus- closely packed stacks of Golgi Apparatus- closely packed stacks of curved membrane –bound sacs.curved membrane –bound sacs.

Its function is to collect modify , package and Its function is to collect modify , package and distribute proteins and lipids manufactured distribute proteins and lipids manufactured by the Endoplasmic Reticulumby the Endoplasmic Reticulum

May also chemically modify the proteins by May also chemically modify the proteins by attaching carbohydrates or lipids to themattaching carbohydrates or lipids to them

Found in great number in cells tat make a Found in great number in cells tat make a great deal of protein e.g. pancreasgreat deal of protein e.g. pancreas

Secretory VesiclesSecretory Vesicles

a vesiclea vesicle is a small membrane bound is a small membrane bound sac that transports or stores materials sac that transports or stores materials within cells within cells

Secretory vesicles – pinch off from the Secretory vesicles – pinch off from the golgi apparatus and move to the golgi apparatus and move to the surface of the cell . Their membranes surface of the cell . Their membranes fuse with the cell membrane and fuse with the cell membrane and release contents to the exterior of the release contents to the exterior of the cellcell

Lysosomes and PeroximesLysosomes and Peroximes

Lysosomes are membrane bound Lysosomes are membrane bound vesicles formed from the golgi vesicles formed from the golgi apparatus . They contain a variety of apparatus . They contain a variety of enzymes that functions as intracellular enzymes that functions as intracellular digestive systemsdigestive systems

Peroxisomes small membrane bound Peroxisomes small membrane bound vesicles containing enzymes that break vesicles containing enzymes that break down fatty acids , amino acids and down fatty acids , amino acids and hydrogen peroxide.hydrogen peroxide.

MitochondriaMitochondria

Mitochondria- small bean shaped, long Mitochondria- small bean shaped, long threadlike organelles that has inner and threadlike organelles that has inner and outer membranes separated by a space. outer membranes separated by a space. The outer membranes have a smooth The outer membranes have a smooth corebut the inner membrane has corebut the inner membrane has numerous folds called cristae numerous folds called cristae

Site of ATP production within the cells and Site of ATP production within the cells and carry out aerobic respirationcarry out aerobic respiration

muscle cellsmuscle cells

CytoskeletonCytoskeleton

Cytoskeleton- consists of proteins Cytoskeleton- consists of proteins that support the cell , hold organelles that support the cell , hold organelles in place and enable the cell to in place and enable the cell to change shape.change shape.

Microtubules, Microfilaments Microtubules, Microfilaments and Intermediate filamentsand Intermediate filaments

MicrotubulesMicrotubules

MicrofilamentsMicrofilaments

Intermediate filamentsIntermediate filaments

CentriolesCentrioles

Centosome- a specialized zone of Centosome- a specialized zone of cytoplasm close to the nucleus that is the cytoplasm close to the nucleus that is the center of microtubule formation.center of microtubule formation.

It contains the It contains the centrioles normally centrioles normally oriented perpendicular to each otheroriented perpendicular to each other

Shaped like a cylinder and has nine Shaped like a cylinder and has nine triplets , each consisting of three triplets , each consisting of three

parallel microtubules joined together. parallel microtubules joined together.

Protein SynthesisProtein Synthesis

DNA in nucleolus is Transcribed to DNA in nucleolus is Transcribed to MRNAMRNA

MRNA is translated at the level of the MRNA is translated at the level of the ribosomal subunits where the codons ribosomal subunits where the codons are read and translated into amino are read and translated into amino acidsacids

The amino acids form peptide bonds The amino acids form peptide bonds to create one larger proteinto create one larger protein

DNA and RNADNA and RNA

DNA has 4 nitrogenous bases : adenine, DNA has 4 nitrogenous bases : adenine, guanine, cytosine and thiamine plus the guanine, cytosine and thiamine plus the sugar deoxyribosesugar deoxyribose

RNA has 4 nitrogenous bases : adenine, RNA has 4 nitrogenous bases : adenine, guanine, cytosine and uracil plus the sugar guanine, cytosine and uracil plus the sugar ribose.ribose.

Remember there are 64 sets of codons (a Remember there are 64 sets of codons (a codon is 3 base pairs) that encode for only codon is 3 base pairs) that encode for only 20 amino acids20 amino acids

Fate of the CellFate of the Cell

Divides ( Mitosis and Meiosis)Divides ( Mitosis and Meiosis) DifferentiatesDifferentiates ApoptosisApoptosis Tumor ( Benign or Malignant) Tumor ( Benign or Malignant) Ages Ages Death * The Cloning of Death * The Cloning of

CellsCells

Mitosis all cells except sex cell(meiosis)Mitosis all cells except sex cell(meiosis)

InterphaseInterphase ProphaseProphase MetaphaseMetaphase AnaphaseAnaphase TelophaseTelophase CytokinesisCytokinesis

Cell DivisionCell Division

DifferentiationDifferentiation We learned that through mitosis all We learned that through mitosis all

cells in an individuals body contain cells in an individuals body contain the same amount and type of DNAthe same amount and type of DNA

So, even though the genetic material So, even though the genetic material is the same , why is it that cells do is the same , why is it that cells do not look and function the same way, not look and function the same way, example of diverse cells in textexample of diverse cells in text

The process by which a cell develop The process by which a cell develop special structure and functions is special structure and functions is called DIFFERENTIATION.called DIFFERENTIATION.

What happens during What happens during differentiation?differentiation?

DNA is either active or inactive DNA is either active or inactive pending in the cell type via the pending in the cell type via the selective activation of certain selective activation of certain portions of the DNA portions of the DNA

As they mature and differentiate As they mature and differentiate the rate eventually slows and stopsthe rate eventually slows and stops

ApoptosisApoptosis

Programmed cell death is a normal Programmed cell death is a normal process by which cell numbers within process by which cell numbers within various tissues are adjusted and various tissues are adjusted and controlled . During development any controlled . During development any extra tissue s removed, such as the extra tissue s removed, such as the webs between the toes and the webs between the toes and the fingers.fingers.

Cellular AgingCellular Aging

Cellular Clock after a certain time or number of Cellular Clock after a certain time or number of cell divisions cell death occurs in a given linecell divisions cell death occurs in a given line

Death genes turn on causing cells to Death genes turn on causing cells to deteriorate deteriorate

DNA damage over yearsDNA damage over years Free Radicals (unpaired electrons) cause direct Free Radicals (unpaired electrons) cause direct

damage via mutationsdamage via mutations Mitochondrial damage causes a loss of energy Mitochondrial damage causes a loss of energy

needed to maintain cell lifeneeded to maintain cell life

Cellular Tumor TransformationCellular Tumor Transformation Tumor- any swelling that occurs Tumor- any swelling that occurs

within the bodywithin the body malignant- spreads rapidly, can get malignant- spreads rapidly, can get

largelarge

benign- can get large benign- can get large

CancerCancer

Cancers are malignant spreading tumors Cancers are malignant spreading tumors Can spread via the lymphatic, hematologic, or local expansion Can spread via the lymphatic, hematologic, or local expansion routesroutesGrowth becomes out of control and the cancer breaks away from Growth becomes out of control and the cancer breaks away from normal controlnormal control

Occur as a result of viruses, toxinsOccur as a result of viruses, toxins

Treatment in the form of Treatment in the form of ChemotherapyChemotherapyImmunotherapyImmunotherapyRadiotherapy ‘Radiotherapy ‘Starvation to cancerStarvation to cancer

Cloning Cloning

A nucleus removed from a A nucleus removed from a differentiated cell can be transferred differentiated cell can be transferred to an oocyte with the nucleus to an oocyte with the nucleus removed and a complete frog can be removed and a complete frog can be formed formed