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CELLS All organisms are made up of cells The cell is the unit of structure and function of all living things Life arises from the interaction of all cellular components. You must check this web site www.cellsalive.com There is correlation between the structure of cells and their function

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Cells l.jpg
CELLS

  • All organisms are made up of cells

  • The cell is the unit of structure and function of all living things

  • Life arises from the interaction of all cellular components.


You must check this web site l.jpg
You must check this web site

  • www.cellsalive.com


There is correlation between the structure of cells and their function l.jpg
There is correlation between the structure of cells and their function

Ex: The shapes of muscles cells, sperm cells, red blood cells,, nerve cells are appropriate for their function.

Example: the flat tile like epithelial cells of the skin fit closely together making a barrier to bacterial entrance, water loss etc.

Another way to say this is that

“shape reflects function”


Slide4 l.jpg

10 m their function

Human height

1 m

Length of somenerve andmuscle cells

100 mm(10 cm)

Unaided eye

Chicken egg

10 mm(1 cm)

Frog egg

1 mm

100 m

Light microscope

Most plant andanimal cells

10 m

Nucleus

Most bacteria

Mitochondrion

1 m

Mycoplasmas(smallest bacteria)

100 nm

Viruses

Electron microscope

Ribosome

10 nm

Proteins

Lipids

1 nm

Small molecules

Atoms

0.1 nm

How small are cells?

Most cells are microscopic

  • Cells vary in size and shape


History l.jpg
History their function

  • Robert Hook (1665) named “cells” after observing tiny compartments in cork .

  • Anton VanLeeuwenhoek (1600’s) improved the primitive microscopes and observed one celled organisms, even bacteria. He documented his findings with letters and diagrams to the Royal Society (of Science) in London.

  • Robert Brown (1600’s)discovered the nucleus

  • Electron microscope was developed in the late 1930’s and allows scientist to see up to 0.5 nanometers. About 1000 times larger than regular microscopes.


How are cells studied l.jpg

Eyepiece their function

Ocularlens

Objective lens

Specimen

Condenserlens

Lightsource

How are cells studied?

Microscopes and Biochemistry

  • The light microscope (LM) magnify cells up to 1000 times

    • Enables us to see the overall shape and structure of a cell

Figure 4.1A


Slide7 l.jpg

TEM 2,800 their function

SEM 2,000 

Figure 4.1D

Figure 4.1C

  • The electron microscope

    • Allows greater magnification and reveals cellular details


The cell theory mid 1800 s l.jpg
The cell theory (mid-1800’s) their function

  • Mathew Schleiden and Theodor Schwann examined plant and animal tissues and came to the conclusion that they both consist of cells

  • Rudolph Virchow came to the conclusion that young cells come from the division of other cells

  •  1.    All organisms are made up of cells

  • 2.    Cells are the units of structure and function of all living things, that is cells have all the properties of life.

  • 3.    All cells come from pre-existing cells


Slide9 l.jpg

Prokaryotic cell their function

Nucleoidregion

Colorized TEM 15,000 

Nucleus

Eukaryotic cell

Organelles

  • Prokaryotic cells are structurally simpler than

  • eukaryotic cells

    • There are two kinds of cells

      • Prokaryotic- No nucleus- Bacteria and Archeae

      • Eukaryotic- have nucleus- plants, animals and fungi

Figure 4.3A


Slide10 l.jpg

Prokar their functionyoticflagella

Ribosomes

Capsule

Cell wall

Plasmamembrane

Nucleoid region (DNA)

Pili

  • TYPE OF CELLS: Prokaryotic and Eukaryotic

  • Prokaryotic cells are small, relatively simple cells

    • That do not have a membrane-bound nucleus


Slide11 l.jpg

Eukaryotic their function cells have a nucleus and are

partitioned into functional compartments.

  • All other forms of life( plants and animals) are composed of complex eukaryotic cells

  • Membranes form compartments inside eukaryotic cells to facilitate metabolic activities


Slide12 l.jpg

10 their functionm

30 m

30 m

10 m

Surface areaof one large cube 5,400m2

Total surface areaof 27 small cubes 16,200m2

  • A small cell has a greater ratio of surface area to volume

    • Than a large cell of the same shape


Slide13 l.jpg

Smooth endoplasmic their functionreticulum

Nucleus

Roughendoplasmicreticulum

Flagellum

Not in mostplant cells

Lysosome

Ribosomes

Centriole

Golgiapparatus

Peroxisome

Microtubule

Plasma membrane

Intermediatefilament

Cytoskeleton

Mitochondrion

Microfilament

  • A typical animal cell

    • Contains a variety of membranous organelles


The cytoskeleton and related structures l.jpg

Tubulin subunit their function

Actin subunit

Fibrous subunits

25 nm

10 nm

7 nm

Microtubule

Microfilament

Intermediate filament

THE CYTOSKELETON AND RELATED STRUCTURES

The cell’s internal skeleton helps organize its structure and activities

  • A network of protein fibers

    • Make up the cytoskeleton.


Functions of the cytoskeleton l.jpg
Functions of the cytoskeleton their function

  • Tubules and filaments are made up of protein fibers

  • Microfilaments of actin

    • Enable cells to change shape and move

  • Intermediate filaments

    • Reinforce the cell and anchor organelles

  • Microtubules give the cell rigidity

    • provide anchors for organelles and act as tracks for organelle movement


Slide16 l.jpg

Over their functionview: Many cell organelles are connected through the endomembrane system


Slide17 l.jpg

  • All cells on earth their function are enclosed in membranes that maintain internal conditions different from the surroundings, have DNA as their genetic material and can convert forms of energy from one to another.

  • Membranes form the boundaries of many eukaryotic cells

    • Compartmentalizing the interior of the cell and facilitating a variety of metabolic activities


Slide18 l.jpg

Nucleus their function

Chromatin

Two membranesof nuclearenvelope

Nucleolus

Pore

Roughendoplasmicreticulum

Ribosomes

  • The nucleus is the cellular control center

    • Containing the cell’s DNA, which directs cellular activities

Figure 4.5


Organelles of the endomembrane system l.jpg
ORGANELLES OF THE ENDOMEMBRANE SYSTEM their function

The nucleus is the cell’s genetic control center

  • The largest organelle is usually the nucleus

    • Which is separated from the cytoplasm by the nuclear envelope


Inside the nucleus l.jpg
Inside the nucleus their function

  • Chromatin fibers made up of DNA

    These thin fibers coil up during cell division becoming thicker and visible. They are called now a chromosome

    Nucleolus makes ribosomes


Slide21 l.jpg

Transport vesicle their functionbuds off

4

Ribosome

Secretory(glyco-) proteininside trans-port vesicle

3

Sugar chain

1

2

Glycoprotein

Polypeptide

Rough ER

  • Ribosomes on the surface of the rough ER

    • Produce proteins that are secreted, inserted into membranes, or transported in vesicles to other organelles


Slide22 l.jpg

Smooth ER their function

Rough ER

Nuclearenvelope

Ribosomes

Rough ER

Smooth ER

TEM 45,000

The endomembrane system is a collection of membranous organelles

  • That manufactures and distributes cell products\

    Smooth endoplasmic reticulum has a variety of functions

  • Smooth endoplasmic reticulum, or smooth ER

    • Synthesizes lipids

    • Processes toxins and drugs in liver cells

    • Stores and releases calcium ions in muscle cells


  • Slide23 l.jpg

    Smooth endoplasmic their functionreticulum

    Nucleus

    Roughendoplasmicreticulum

    Flagellum

    Not in mostplant cells

    Lysosome

    Ribosomes

    Centriole

    Golgiapparatus

    Peroxisome

    Microtubule

    Plasma membrane

    Intermediatefilament

    Cytoskeleton

    Mitochondrion

    Microfilament

    • A typical animal cell

      • Contains a variety of membranous organelles


    Slide24 l.jpg

    Golgi apparatus their function

    “Receiving” side ofGolgi apparatus

    Golgiapparatus

    Transportvesiclefrom ER

    TEM 130,000

    New vesicleforming

    Transportvesicle fromthe Golgi

    “Shipping” sideof Golgi apparatus

    The Golgi apparatus finishes, sorts, and ships cell products

    • Stacks of membranous sacs receive and modify ER products

      • Then ship them to other organelles or the cell surface

    Figure 4.9


    Slide25 l.jpg

    Transport vesicle from their functionGolgi to plasma membrane

    Transport vesiclefrom ER to Golgi

    Rough ER

    Plasmamembrane

    Nucleus

    Vacuole

    Lysosome

    Nuclear envelope

    Smooth ER

    Golgi apparatus

    The endomembrane system

    • The various organelles of the endomembrane system

      • Are interconnected structurally and functionally


    Slide26 l.jpg

    Mitochondrion their function

    Outermembrane

    Intermembranespace

    Innermembrane

    TEM 44,880

    Cristae

    Matrix

    Mitochondria gets chemical energy from food

    • Mitochondria carry out cellular respiration

      It uses the chemical energy in food to make ATP for cellular work


    Slide27 l.jpg

    Rough ER their function

    1

    Transport vesicle(containing inactivehydrolytic enzymes)

    Golgiapparatus

    Plasmamembrane

    Lysosomeengulfingdamagedorganelle

    2

    Engulfmentof particle

    Lysosomes

    3

    5

    4

    Foodvacuole

    Digestion

    Lysosomes are digestive compartments within a cell

    • Lysosomes are sacs of enzymes that function in digestion within a cell

    “Food”


    Slide28 l.jpg

    Lysosome their function

    Nucleus

    TEM 8,500

    • Lysosomes in white blood cells

      • Destroy bacteria that have been ingested

      • lysosomes also help to digest worn out , damaged cell parts, recycle materials within the cell and fuse with food vacuoles to digest nutrients.

    Figure 4.10B


    Slide29 l.jpg
    Lysosomes in white blood cells destroy bacteria and lysosomes also can digest other parts of the cell

    Abnormal lysosomes can cause fatal diseases

    • Lysosomal storage diseases. These are rare.

      • Interfere with various cellular functions

      • Ex: Tay- Sachs, does not break down lipids in nerve cell membranes. Lipids accumulate

      • Pompe’s disease, lysosomes cannot digest glycogen and it accumulates in muscle and liver cells


    Peroxisomes l.jpg
    Peroxisomes lysosomes also can digest other parts of the cell

    • Specialized vesicles that contains enzymes (catalase) that digest hydrogen peroxide H2O2

    • Our cells produce hydrogen peroxide during metabolism and the enzymes in peroxisomes break it down into water and oxygen gas which are harmless to the cell.


    Plant cells l.jpg
    Plant Cells lysosomes also can digest other parts of the cell

    • Three organelles animals do not have

      Chloroplasts

      Cell wall

      Central vacuole


    Slide32 l.jpg

    Rough lysosomes also can digest other parts of the cellendoplasmicreticulum

    Nucleus

    Ribosomes

    Smoothendoplasmicreticulum

    Golgiapparatus

    Microtubule

    Centralvacuole

    Intermediatefilament

    Cytoskeleton

    Not inanimalcells

    Microfilament

    Chloroplast

    Cell wall

    Mitochondrion

    Peroxisome

    Plasma membrane

    • A typical plant cell has some structures that an animal cell lacks

      • Such as chloroplasts and a rigid cell wall


    Energy converting organelles l.jpg

    Chloroplast lysosomes also can digest other parts of the cell

    Stroma

    Inner and outermembranes

    TEM 9,750

    Granum

    Intermembranespace

    ENERGY-CONVERTING ORGANELLES

    Chloroplasts convert solar energy to chemical energy. This is where PHOTOSYNTHESIStakes place

    • Chloroplasts, found in plants and some protists

      Convert solar energy to chemical energy in sugars


    Slide34 l.jpg

    Nucleus lysosomes also can digest other parts of the cell

    Chloroplast

    Centralvacuole

    Colorized TEM 8,700

    Vacuoles function in the general maintenance of the cell

    • Plant cells contain a large central vacuole,

      • Which has lysosomal and storage functions


    Central vacuoles in plants l.jpg
    Central vacuoles in plants lysosomes also can digest other parts of the cell

    Also help increase the size of cells by absorbing water

    Are mostly water, minerals and nutrients

    • Store color pigments (that attract insects)

    • Store waste products and poisons


    Slide36 l.jpg

    Nucleus lysosomes also can digest other parts of the cell

    Contractilevacuoles

    LM 650

    • Some protists have contractile vacuoles

      • That pump out excess water


    Organelles l.jpg
    Organelles lysosomes also can digest other parts of the cell

    • NAME LOCATION FUNCTION

    • CytoskeletoncytoplasmMaintains cell shape

      facilitates movement and move

      materials within the cell

    • Cytosol cytoplasmProtein rich fluid in which

      organelles and cytoskeleton

      are immersed

    • NucleusInside nuclear envelopeSite of most of cell’s DNA

      and nucleolus

    • Nucleolus Inside the nucleus Synthesis of ribosomal RNA


    Organelles38 l.jpg
    ORGANELLES lysosomes also can digest other parts of the cell

    NAME LOCATION FUNCTION

    • Rough Endoplasmic Reticulum cytoplasm Protein synthesis,Cell metabolism,

    • Smooth Endoplasmic Reticulum cytoplasm Lipid synthesis, storage of calcium,

      Detoxification of toxic substances

    • Ribosomes Rough ER and Protein synthesis

      free in the cytoplasm

    • Vesiclesmove through cytoplasmTransport

    • Golgi BodiescytoplasmProcessing, sorting,

      shipping of proteins and lipids

    • Mitochondria cytoplasm Gets energy from food (makes ATP

      during aerobic respiration)


    Organelles39 l.jpg
    ORGANELLES lysosomes also can digest other parts of the cell

    NAME LOCATION FUNCTION

    • Lysosomes cytoplasm Digestion and breaking down of materials

      (only in animal cells) ( including the cell’s own)

    • Peroxisomes cytoplasm Sacs of enzymes that break down substances

      (alcohol, amino acids) into hydrogen peroxide

      and then the hydrogen peroxide into water

      and oxygen.

    • Plasma Membrane all around the cell Controls substances and signals that go in

      and out of cells. Maintains shape and

      volume

    • Cell wall ( plant cells) cytoplasm Keeps water inside and limits water

      uptake, protects from outside influences,

      maintains shape.


    Organelles40 l.jpg
    ORGANELLES lysosomes also can digest other parts of the cell

    NAME LOCATION FUNCTION

    • Central vacuoles center of plant cell water maintenance, stores waste

      (plant cells only)

    • Plastids cytoplasm plastids provide nutrients and

      (plant cells only) pigmentation

    • Chloroplast many throughout carry out photosynthesis

      (plant cells only) the cytoplasm contain chlorophyll


    Cell junctions l.jpg
    CELL JUNCTIONS lysosomes also can digest other parts of the cell

    • What are junctions? Protein or cytoplasmic bridges that serve as physical links between cells.

    • The junctions between cells help integrate cells into tissues and higher levels of functioning. Junctions make cells living units greater than each individual part.

    • Junctions serve to send and receive signals and materials and to cement itself to other cells and junctions coordinate cell activities.


    Plant cells42 l.jpg
    Plant cells lysosomes also can digest other parts of the cell

    Plants are covered by cell walls composed of cellulose fibers.

    Cell walls have plasmodesmata, these are channels that pass through adjoining cell walls connecting plant cell to plant cell.


    Animal cells junctions l.jpg
    Animal cells: lysosomes also can digest other parts of the cellJunctions

    • There are different kinds of intracellular junctions between animal cells, integrating each cell into a greater unit.

    • Tight junctions

    • Desmosomes or Anchoring juctions:

    • Gap or Communication junctions:


    Tight junctions l.jpg
    Tight junctions lysosomes also can digest other parts of the cell

    They fuse cell to cell to prevent leakage. Ex: cells of the lining of the intestines keeping the fluid inside. All cells of most tissues are joined this way. The skin and the lining of internal cavities (epithelial).


    Gap or communication junctions l.jpg
    Gap or Communication junctions: lysosomes also can digest other parts of the cell

    Link the cytoplasm of neighboring cells. They are open channels that allow a flow of materials and signals between cells.

    • Very common in embryos and in heart tissue to allow for the passage of ions to cause contraction


    Desmosomes or anchoring juctions l.jpg
    Desmosomes or Anchoring juctions: lysosomes also can digest other parts of the cell

    Joins cells in tissues of the skin, heart and other organs such as the bladder subject to stretching.


    Slide47 l.jpg

    Tight junctions lysosomes also can digest other parts of the cell

    Anchoring junction

    Gap junctions

    Extracellular matrix

    Space between cells

    Plasma membranes of adjacent cells

    • Tight junctions can bind cells together into leakproof sheets

    • Anchoring junctions link animal cells into strong tissues

    • Gap junctions allow substances to flow from cell to cell

    Figure 4.18B


    Cilia and flagella l.jpg

    Colorized SEM 4,100 lysosomes also can digest other parts of the cell

    LM 600

    Figure 4.17A

    Figure 4.17B

    Cilia and flagella

    • move when microtubules bend

      • Eukaryotic cilia and flagella are locomotor appendages that protrude from some cells


    Clusters of microtubules drive the whipping action of these organelles l.jpg

    Flagellum lysosomes also can digest other parts of the cell

    Electron micrographsof cross sections:

    Outer microtubuledoublet

    Centralmicrotubules

    TEM 206,500

    Radial spoke

    Dynein arms

    Flagellum

    Plasmamembrane

    TEM 206,500

    Basal body(structurally identical to centriole)

    Basal body

    Clusters of microtubules Drive the whipping action of these organelles

    .


    Plasma membrane l.jpg
    PLASMA MEMBRANE lysosomes also can digest other parts of the cell

    • Function:

      The cell’s “gate keeper”. Very important.

      It controls what goes in and out of a cell.

      Keeps equilibrium between the inside of cells and the outside and promotes homeostasis.

      Web site to check:

      http://www.wisc-online.com/objects/index_tj.asp?objid=AP1101

    • Function:

      The cell’s “gate keeper”. Very important.

      It controls what goes in and out of a cell.

      Keeps equilibrium between the inside of cells and the outside and promotes homeostasis.

      Web site to check:

      http://www.wisc-online.com/objects/index_tj.asp?objid=AP1101


    Membranes l.jpg
    Membranes lysosomes also can digest other parts of the cell

    • http://www.wiley.com/legacy/college/boyer/0470003790/animations/membrane_transport/membrane_transport.htm


    Slide52 l.jpg

    Outside lysosomes also can digest other parts of the cellof cell

    Cytoplasm

    TEM 200,000 

    The plasma membrane of the cell is selectively permeableControlling the flow of substances into or out of the cell


    Plasma membrane53 l.jpg
    PLASMA MEMBRANE lysosomes also can digest other parts of the cell

    STRUCTURE:

    It is a LIPID BILAYER. Its main component is a PHOSPHOLIPID molecule.

    • A phospholipid is made up of a hydrophilic head (water loving) and two hydrophobic fatty acid tails (dislike water). These are arranged in two layers with the fatty acids tails sandwiched between the hydrophilic heads.

    • The membrane is “fluid”, it moves about, tails twist and wave

    • Embedded in the phospholipid bilayer are the surface proteins.

    • The membrane is “a mosaic” of different proteins embedded in the fluid matrix of the lipid bilayer.


    What makes up the plasma membrane l.jpg

    CH lysosomes also can digest other parts of the cell3

    Hydrophilic head

    +

    N

    CH2

    CH3

    CH3

    CH2

    Phosphategroup

    O

    P

    O–

    O

    O

    CH

    CH2

    CH2

    O

    O

    O

    O

    C

    C

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    Symbol

    CH2

    CH2

    CH

    CH2

    CH

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH2

    CH3

    CH3

    Hydrophobic tails

    What makes up the plasma membrane?

    • Phospholipids are the main structural components of membranes

      Membrane phospholipids form a bilayer

      • Have a hydrophilic head and two hydrophobic tails


    Slide55 l.jpg

    Water lysosomes also can digest other parts of the cell

    Hydrophilicheads

    Hydrophobictails

    Water

    Phospholipids form a two-layer sheetCalled a phospholipid bilayer, with the heads facing outward and the tails facing inward


    How does it work l.jpg
    How does it work? lysosomes also can digest other parts of the cell

    • Membrane is selectively permeable or semi-permeable. Small molecules that are electrically neutraldiffuse easily in and out such as O2, CO2, and alcohols.

    • The non-polar phospholipid tails of the bilayer repel charged molecules but allow lipid soluble molecules to pass easily.

    • Sugars need to be transported through a channel as well as charged ions such as H+, Na+, K+, Cl


    Slide57 l.jpg

    • Large molecules lysosomes also can digest other parts of the cell (like proteins) cannot diffuse through and must enter the cell by other mechanisms such as active transport. Active transport uses energy (ATP) to “push” the molecules in and out.

    • Serious diseases associated with cell membrane defects:

      Multiple Sclerosis, there is a myelin cover on axons of nerve cells. Because it is defective muscle control is lost

      Cystic Fibrosis, The channels for chloride to pass through the membrane do not work. Chloride ion are not able to leave the cell. Results in thick mucus in respiratory track and other ducts in the body.


    Proteins found in the plasma membrane l.jpg
    Proteins found in the plasma membrane: lysosomes also can digest other parts of the cell

    • Integral penetrate the hydrophobic core of the lipid bilayer

    • Peripheral are loosely bound to the surface of the membrane

    • Transport proteins

    • Receptor proteins

    • Recognition proteins

    • Adhesion proteins


    Proteins found in the plasma membrane59 l.jpg
    Proteins found in the plasma membrane: lysosomes also can digest other parts of the cell

    • Transport proteins:

      These are open on both sides making a channel, a passage. Water soluble substances pass through it. It is very specific for the substance that it moves.

    • Receptor proteins:

      Grab or bind substances to pass them through. Have a binding site with a specific shape that fits the shape of another molecule. It can bind a chemical messenger such as a hormone which then causes a change in the shape of the protein that relays the message to the inside of the cell.

    • Recognition proteins:

      These are glycoproteins. Have a short chain of sugars attached to it.

      Are like fingerprints. Serve as identification tags that are recognized by other cells. Your cells recognize “your own”

    • Adhesion proteins:

      Like “glue”, make cells stick together.


    Slide60 l.jpg

    Fibers of the lysosomes also can digest other parts of the cellextracellular matrix

    Carbohydrate(of glycoprotein)

    Glycoprotein

    Glycolipid

    Plasmamembrane

    Phospholipid

    Proteins

    Cholesterol

    Microfilamentsof cytoskeleton

    Cytoplasm

    The membrane is a fluid mosaic of phospholipids with proteins and other molecules embedded in a phospholipid bilayer


    Membrane proteins also function in transport moving substances across the membrane l.jpg

    ATP lysosomes also can digest other parts of the cell

    Membrane proteins also function in transportMoving substances across the membrane


    Other membrane proteins function as receptors for chemical messages from other cells l.jpg

    Messenger molecule lysosomes also can digest other parts of the cell

    Receptor

    Activatedmolecule

    Other membrane proteinsFunction as receptors for chemical messages from other cells


    Many membrane proteins function as enzymes l.jpg
    Many membrane proteins lysosomes also can digest other parts of the cellFunction as enzymes


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