Theodore Schwann Theodore Schwann and Matthias and Matthias Schleiden and Schleiden and Virchow composed Virchow composed the cell theory.the cell theory.

Cell TheoryCell Theory

1. All living organisms are composed of 1. All living organisms are composed of cells and cell products.cells and cell products.

2. The cell is the basic unit of structure 2. The cell is the basic unit of structure and function of all living organisms.and function of all living organisms.

3. All cells come from pre-existing cells.3. All cells come from pre-existing cells. 4. An organism as a whole can be 4. An organism as a whole can be

understood through the collective understood through the collective activities and interactions of cells.activities and interactions of cells.

Cytologist-scientist who study cells.Cytologist-scientist who study cells.

The adult human body has about 75 The adult human body has about 75 trillion cells. They are measured in trillion cells. They are measured in units called micrometers.units called micrometers.

Cells vary in shape----their shape is Cells vary in shape----their shape is related to their function.related to their function.

----Nerve cells—long thread-like and ----Nerve cells—long thread-like and transmit impulses from one body part transmit impulses from one body part to another.to another.

----Epithelial cells--line inside of mouth ----Epithelial cells--line inside of mouth and are flattened, tightly packed and and are flattened, tightly packed and look like floor tiles. (Protect and shield)look like floor tiles. (Protect and shield)

----Muscle cells—slender and rod-like--------Muscle cells—slender and rod-like----ends attached to parts they move.ends attached to parts they move.

Anatomy—The CellAnatomy—The Cell

Basic Unit of LifeBasic Unit of Life

You cannot You cannot describe a typical describe a typical cell due to cell due to variations in size, variations in size, shape, content, shape, content, and function. The and function. The cells we look at are cells we look at are called “composite called “composite cells”.cells”.

Parts of a CellParts of a Cell

Nucleus---innermost part enclosed by a Nucleus---innermost part enclosed by a nuclear membrane.nuclear membrane.

Cytoplasm---mass of fluid that surrounds Cytoplasm---mass of fluid that surrounds the nucleus.the nucleus.

Cytosol---fluid portion of cytoplasm—all Cytosol---fluid portion of cytoplasm—all metabolic reactions occur here.metabolic reactions occur here.

Cell membrane---(plasma membrane or Cell membrane---(plasma membrane or cytoplasmic membrane) outer most limit of cytoplasmic membrane) outer most limit of cell.cell.

Characteristics of Cell Characteristics of Cell membranemembrane

Thin—visible with a microscope onlyThin—visible with a microscope only Complex surface features outpouchings and Complex surface features outpouchings and

infoldingsinfoldings These provide extra surface areaThese provide extra surface area Seals itself after injury quickly. If too injured, Seals itself after injury quickly. If too injured,

contents of cell escapes and cell dies.contents of cell escapes and cell dies. It is selectively permeable and allows some It is selectively permeable and allows some

substances to pass through and refuses substances to pass through and refuses others.others.

Structure:Structure:

Composed of lipids and proteins and Composed of lipids and proteins and some carbohydrates.some carbohydrates.

Double layer of phospholipid moleculesDouble layer of phospholipid molecules Contains lots of protein and few lipids.Contains lots of protein and few lipids.

Framework: double layer of Framework: double layer of phospholipid molecules.phospholipid molecules.

Water soluble heads (hydrophilic) Water soluble heads (hydrophilic) form surface and water insoluble tails form surface and water insoluble tails (hydrophobic) form interior of (hydrophobic) form interior of membrane. membrane.

Blood cells are not in direct contact Blood cells are not in direct contact with one another because of fluid-with one another because of fluid-filled spaces(intercellular spaces) filled spaces(intercellular spaces) separate them.separate them.

3 Types of intercellular 3 Types of intercellular junctions:junctions:

Tight junctions – membranes of adjacent cells Tight junctions – membranes of adjacent cells converge and becomes fused together. It converge and becomes fused together. It surrounds the cell like a belt. The cells form surrounds the cell like a belt. The cells form sheet-like layers like the digestive tube.sheet-like layers like the digestive tube.

Desmosome – rivets or “spot welds” adjacent Desmosome – rivets or “spot welds” adjacent cells and forms reinforced structural unit. Skin cells and forms reinforced structural unit. Skin CellsCells

Gap junction – tubular channels that link Gap junction – tubular channels that link cytoplasm of adjacent cells and allows ions and cytoplasm of adjacent cells and allows ions and nutrients to exchange between them. Heart nutrients to exchange between them. Heart muscle and muscle of digestive tube.muscle and muscle of digestive tube.

Draw the plasma membraneDraw the plasma membraneInclude and label the following:Include and label the following: Phospholipid heads Phospholipid heads Fatty acid tailsFatty acid tails Cholesterol Cholesterol Channel proteinsChannel proteins Pore proteinsPore proteins Glycoprotein/Receptor proteinsGlycoprotein/Receptor proteins Fibrous proteinsFibrous proteins Identify hydrophobic and hydrophilic regionsIdentify hydrophobic and hydrophilic regions

Other Cell Structures:Other Cell Structures:

Cytoplasm—It Cytoplasm—It contains network contains network of membranes and of membranes and other organelles other organelles suspended in clear suspended in clear liquid cytosol.liquid cytosol.

Nucleoplasm—Nucleoplasm—material inside the material inside the nucleus.nucleus.

ER—(Endoplasmic ER—(Endoplasmic reticulum)- complex reticulum)- complex organelle composed of organelle composed of membrane-bound membrane-bound flattened sacs, flattened sacs, elongated canals and elongated canals and fluid-filled vesicles.fluid-filled vesicles.

Communication Communication systemsystem

Rough ER-ribosomes Rough ER-ribosomes attached.attached.

Smooth ER-no Smooth ER-no ribosomesribosomes

Ribosomes—sites Ribosomes—sites of protein synthesis of protein synthesis in the cell.in the cell.

Golgi apparatus—Golgi apparatus—located near the located near the nucleus. It is nucleus. It is composed of composed of flattened membrane flattened membrane sacs called sacs called cisternae.cisternae.

Refining, packaging Refining, packaging and delivery of and delivery of protein. protein.

Mitochondria—Mitochondria—elongated fluid elongated fluid filled—energy filled—energy producer producer powerhouse of the powerhouse of the cellcell

Cristae—inner Cristae—inner membrane membrane foldings.foldings.

Lysosomes—Lysosomes—shapes vary---shapes vary---contains powerful contains powerful enzymes to digest enzymes to digest many particles. many particles. They also function They also function in destruction of in destruction of worn cell parts.worn cell parts.

Peroxisome– Peroxisome– membranous sacs membranous sacs that resemble that resemble lysosomes in size lysosomes in size and shape. Found and shape. Found in liver and kidney in liver and kidney cellscells

Break down fatty Break down fatty acids and help acids and help Detoxify Alcohol.Detoxify Alcohol.

Centrosome—Central body located in Centrosome—Central body located in cytoplasm near Golgi apparatus and cytoplasm near Golgi apparatus and nucleus consists of hollow cylinders nucleus consists of hollow cylinders called centrioles which help carry called centrioles which help carry DNA information.DNA information.

Cilia and flagella – Cilia and flagella – motile processes motile processes that extend that extend outward from outward from surface of the cell. surface of the cell. Cilia – on Cilia – on epithelium; flagella epithelium; flagella – sperm– sperm

Vesicles (vacuole) – membranous Vesicles (vacuole) – membranous sacs that vary in size.sacs that vary in size.

Microfilaments/Microfilaments/microtubules – two microtubules – two types of thin types of thin threadlike threadlike structures found in structures found in cytoplasm to help cytoplasm to help function to form function to form cellular cellular movements.movements.

Nuclear membrane Nuclear membrane – allows substances – allows substances to pass between to pass between nucleus and nucleus and cytoplasm.cytoplasm.

Nucleolus – “little Nucleolus – “little nucleus” small nucleus” small dense body of RNA dense body of RNA and protein and protein

Function: Function: production of production of ribosomes.ribosomes.

Chromatin – loosely coiled fibers in Chromatin – loosely coiled fibers in nuclear fluid (DNA)nuclear fluid (DNA)

Cell MembraneCell Membrane

Substances enter and leave the cellSubstances enter and leave the cell ---oxygen and food enters---oxygen and food enters ---carbon dioxide and waste leave---carbon dioxide and waste leave

The growth of a cell depends The growth of a cell depends on two factors:on two factors:

A. Increase in volume of individual A. Increase in volume of individual cellcell

B. Increase in number of cellsB. Increase in number of cells

If a cell grows too large it dies. It If a cell grows too large it dies. It cannot absorb enough necessary cannot absorb enough necessary materials to supply its volume or get materials to supply its volume or get rid of waste.rid of waste.

Cells are limited in size by their Cells are limited in size by their surface area-volume relationship.surface area-volume relationship.

DiffusionDiffusion

Process in which molecules or ions Process in which molecules or ions become scattered or are spread become scattered or are spread spontaneously from higher to lower spontaneously from higher to lower concentration.concentration.

Particles move and bounce off one Particles move and bounce off one another which mixes them. Ex: another which mixes them. Ex: Sugar cube in waterSugar cube in water

Equilibrium – state of uniform Equilibrium – state of uniform distribution of molecules.distribution of molecules.

Facilitated diffusionFacilitated diffusion Uses carrier molecule to transport insoluble Uses carrier molecule to transport insoluble

material across the cell membrane.material across the cell membrane.

Sugar molecules are insoluble in lipids. Sugar Sugar molecules are insoluble in lipids. Sugar glucose may enter by facilitated diffusion.glucose may enter by facilitated diffusion.

Glucose molecule combines with special Glucose molecule combines with special protein carrier molecule at surface of protein carrier molecule at surface of membrane. Union of glucose and carrier membrane. Union of glucose and carrier molecule forms a compound soluble in liquids molecule forms a compound soluble in liquids that can diffuse to other side. Hormone that can diffuse to other side. Hormone insulin supports process.insulin supports process.

Rate is dependent on number of Rate is dependent on number of carrier molecules in the cell carrier molecules in the cell membrane.membrane.

OsmosisOsmosis

Form of diffusionForm of diffusion Water diffuses from a higher to a lower Water diffuses from a higher to a lower

concentration through a selectively concentration through a selectively permeable membrane.permeable membrane.

Osmotic pressure – the amount of pressure Osmotic pressure – the amount of pressure needed to stop osmosisneeded to stop osmosis

The greater the number of solute particles The greater the number of solute particles in solution, the greater the osmotic in solution, the greater the osmotic pressure.pressure.

Plasmolysis---shrinking of cell Plasmolysis---shrinking of cell contentscontents

Cytolysis---bursting of cellCytolysis---bursting of cell Hemolysis---red blood cells Hemolysis---red blood cells

hemolyze. bursting of red blood hemolyze. bursting of red blood cells.cells.

3 types of solutions:3 types of solutions:

Hypertonic – more Hypertonic – more water leaves the water leaves the cell than enters cell than enters because because concentration of concentration of solute particles is solute particles is greater outside the greater outside the cell.cell.

Hypotonic Hypotonic solution– a solution– a solution in solution in which more which more water enters the water enters the cell than leaves cell than leaves it. Lesser solute it. Lesser solute outside the cell.outside the cell.

Isotonic solution---solution that Isotonic solution---solution that contains same concentration of contains same concentration of solute particles as a particular cell. solute particles as a particular cell. Water enters and leaves the cell at Water enters and leaves the cell at the same rate. Cell remains the same rate. Cell remains unchanged.unchanged.

http://www.tvdsb.on.ca/westmin/sciehttp://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Osmosis.htmnce/sbi3a1/Cells/Osmosis.htm

Active transportActive transport

Particles move from regions of lower Particles move from regions of lower to higher concentration.to higher concentration.

Sodium—higher outside cell than Sodium—higher outside cell than inside cellinside cell

40% of cell’s energy supply may be 40% of cell’s energy supply may be used for active transport.used for active transport.

Filtration – molecules are forced through Filtration – molecules are forced through membrane by hydrostatic pressure usually membrane by hydrostatic pressure usually blood pressure – greater on one side of blood pressure – greater on one side of membrane than the other.membrane than the other.

Also takes place in the kidneys when water Also takes place in the kidneys when water and various substances are forced out of and various substances are forced out of blood vessels and into kidney tubules by blood vessels and into kidney tubules by blood pressure ( first step in formation of blood pressure ( first step in formation of urine)urine)

DialysisDialysis

Dialysis is a method of transport in Dialysis is a method of transport in which diffusible substances are which diffusible substances are separated from non diffusible separated from non diffusible substances in a solution – net substances in a solution – net movement of particles can be movement of particles can be controlled by changing concentration controlled by changing concentration gradients of solute and solvent.gradients of solute and solvent.

EndocytosisEndocytosis

Molecules or other particles that are Molecules or other particles that are too large to enter cell.too large to enter cell.

3 types of endocytosis:3 types of endocytosis:

Pinocytosis—process in which cells Pinocytosis—process in which cells take in tiny drops of liquid from their take in tiny drops of liquid from their surroundings. Small portion of cell surroundings. Small portion of cell membrane indents to form sac that membrane indents to form sac that enters cytoplasm. Cells take in water enters cytoplasm. Cells take in water and dissolved protein.and dissolved protein.

Phagocytosis – same as pinocytosis Phagocytosis – same as pinocytosis except material taken into cell is except material taken into cell is solid rather than liquid. Some WBC’s solid rather than liquid. Some WBC’s are phagocytes which take in are phagocytes which take in bacteria and cell debris.bacteria and cell debris.

Receptor-mediated endocytosis – Receptor-mediated endocytosis – moves specific kinds of particles moves specific kinds of particles through membranes. Certain through membranes. Certain molecules are surrounded by binding molecules are surrounded by binding protein that enables it to enter cell protein that enables it to enter cell (receptor protein)(receptor protein)

Exocytosis---cell expels what is not Exocytosis---cell expels what is not digested.digested.

LectureLecture

http://www.newark.osu.edu/Blamverhttp://www.newark.osu.edu/Blamvermeyer/Ch03a_Lect.pdfmeyer/Ch03a_Lect.pdf

http://bioweb.wku.edu/Faculty/Bowkehttp://bioweb.wku.edu/Faculty/Bowker/120/mitosis.htmlr/120/mitosis.html