Anatomy of Cells. History of the Cell Theory 1.R obert Hooke – 1665 – named cell 2.L eeuwenhoek – 1695 – observed living microorganisms 3.S chwann – 1839.

Anatomy of CellsAnatomy of Cells

History of the Cell TheoryHistory of the Cell Theory

1.1. Robert Hooke – 1665 – named cellRobert Hooke – 1665 – named cell

2.2. Leeuwenhoek – 1695 – observed living Leeuwenhoek – 1695 – observed living microorganismsmicroorganisms

3.3. Schwann – 1839 – all animals made of Schwann – 1839 – all animals made of cellscells

4.4. Schleiden – 1839 – all plants made of cellsSchleiden – 1839 – all plants made of cells

5.5. Virchow – 1855 - all cells come from cellsVirchow – 1855 - all cells come from cells

Cell TheoryCell Theory Cells are the basic structural and functional Cells are the basic structural and functional

units of lifeunits of life Under the conditions present on Earth today Under the conditions present on Earth today

all cells come from other cells.all cells come from other cells. Cells of multicellular organisms must stick to Cells of multicellular organisms must stick to

solid surfaces to perform normally.solid surfaces to perform normally.

Tools of Microscopic AnatomyTools of Microscopic Anatomy

Microscopy Microscopy - the history of cytology is tied to the - the history of cytology is tied to the development of the microscope. development of the microscope.

1.1. Light microscopes (pg. 70 – 71)Light microscopes (pg. 70 – 71)- pass light through the specimen- pass light through the specimen- can magnify up to about 1200x- can magnify up to about 1200x- easy to prepare specimens and can - easy to prepare specimens and can look at living specimens.look at living specimens.- resolving power – ability to - resolving power – ability to distinguish between two objectsdistinguish between two objects

2. Transmission Electron Microscope2. Transmission Electron Microscope - send a beam of electrons through the - send a beam of electrons through the

specimenspecimen - focused with magnets- focused with magnets - resolving power up to 100,000(+)x- resolving power up to 100,000(+)x - specimens have to be prepared and can’t be - specimens have to be prepared and can’t be alivealive

3. Scanning Electron Microscope3. Scanning Electron Microscope - bounce electrons off the surface of the - bounce electrons off the surface of the specimen specimen - gives detailed three-dimensional images of - gives detailed three-dimensional images of the surface of the specimenthe surface of the specimen

Cell FragmentationCell Fragmentation Used to study cell physiologyUsed to study cell physiology Separate the cell into various components and Separate the cell into various components and

study what each component does.study what each component does.

Radioactive Isotope LabelingRadioactive Isotope Labeling Use techniques to get radioactive isotopes of Use techniques to get radioactive isotopes of

various elements into a cell and then study various elements into a cell and then study how the cell uses that element.how the cell uses that element.

Functional Anatomy of CellsFunctional Anatomy of CellsBasic Cell StructuresBasic Cell Structures

1.1. Plasma Membrane – separates the cell Plasma Membrane – separates the cell from its surrounding environmentfrom its surrounding environment

2.2. Cytoplasm – thick gel-like substance Cytoplasm – thick gel-like substance inside the cell housing numerous inside the cell housing numerous organelles suspended in water cytosol; organelles suspended in water cytosol; each type of organelle is suited to a each type of organelle is suited to a particular function.particular function.

3.3. Nucleus – large membranous structure Nucleus – large membranous structure near the center of the cellnear the center of the cell

Why are cells small?Why are cells small?

1.1. Surface-to-volume ratioSurface-to-volume ratio

- cells exchange materials with their - cells exchange materials with their environment through the cell membrane at environment through the cell membrane at their surfacetheir surface

- as structures get larger, their volume - as structures get larger, their volume increases at a faster rate than their surface increases at a faster rate than their surface areaarea

- eventually there is not enough surface area - eventually there is not enough surface area for the needed materials to enter or for waste for the needed materials to enter or for waste materials to exit the cellmaterials to exit the cell

2. Less distance for materials to move within the 2. Less distance for materials to move within the cellcell

- increases probability of molecular collisions - increases probability of molecular collisions and thus of reactions happeningand thus of reactions happening

- within the cell the organelles create even - within the cell the organelles create even smaller compartments for reactions to happen smaller compartments for reactions to happen inin

3. Finite amount of DNA to control the 3. Finite amount of DNA to control the metabolism of the cell.metabolism of the cell.

- DNA only can control the production of - DNA only can control the production of proteins sufficient for a small areaproteins sufficient for a small area

Cell MembranesCell Membranes All of the membranes of the cell have similar All of the membranes of the cell have similar

structure.structure.

Plasma MembranePlasma Membrane Fluid Mosaic Model – developed by Singer and Fluid Mosaic Model – developed by Singer and

NicolsonNicolson Molecules are arranged in a sheetMolecules are arranged in a sheet Molecules can move laterally in the membraneMolecules can move laterally in the membrane Molecules are held together by chemical attractions Molecules are held together by chemical attractions

between them and their interactions with water.between them and their interactions with water. Primary structure is a double layer of phospholipid Primary structure is a double layer of phospholipid

moleculesmolecules Phosphate heads are hydrophilic; tails are Phosphate heads are hydrophilic; tails are

hydrophobichydrophobic

Cholesterol molecules within the membrane Cholesterol molecules within the membrane help it function at body temperatures.help it function at body temperatures.

Because the hydrophobic tails make-up most Because the hydrophobic tails make-up most of the membrane, water soluble materials can’t of the membrane, water soluble materials can’t pass through the membrane.pass through the membrane.

Channel proteins which are embedded in the Channel proteins which are embedded in the membrane help control movement of materials membrane help control movement of materials into and out of the cellinto and out of the cell

Glycoproteins have carbohydrates attached Glycoproteins have carbohydrates attached and serve as cell surface identifiersand serve as cell surface identifiers

Receptor proteins react to specific chemicals Receptor proteins react to specific chemicals and cause changes within the cell.and cause changes within the cell.

Overall, the plasma membrane is selectively Overall, the plasma membrane is selectively permeable.permeable.

Movement through the Movement through the MembraneMembranePassive Transport ProcessesPassive Transport Processes Do not require energy expenditure by the cellDo not require energy expenditure by the cell

1.1. DiffusionDiffusion

- movement of particles from an area of high - movement of particles from an area of high concentration to an area of low concentration concentration to an area of low concentration down a concentration gradient.down a concentration gradient.

- continues until equilibrium is reached- continues until equilibrium is reached

- membrane channels are pores through - membrane channels are pores through which specific ions or small water-soluble which specific ions or small water-soluble molecules can passmolecules can pass

- gases also move by diffusion- gases also move by diffusion

2.2. Carrier-facilitated diffusionCarrier-facilitated diffusion

- movement through carrier proteins along the - movement through carrier proteins along the concentration gradientconcentration gradient

- rate is dependent on concentration gradient and - rate is dependent on concentration gradient and availability of carrier moleculesavailability of carrier molecules

3. Osmosis3. Osmosis- diffusion of water through a selectively permeable - diffusion of water through a selectively permeable membranemembrane- water moves down it’s concentration gradient – this - water moves down it’s concentration gradient – this often means it is moving toward higher salt often means it is moving toward higher salt concentrationsconcentrations- - Osmotic Pressure Osmotic Pressure – water pressure that develops as a – water pressure that develops as a result of osmosisresult of osmosis- healthy cells are normally in an environment where - healthy cells are normally in an environment where the net movement of water is 0.the net movement of water is 0.- Tonicity – ability of a solution to move water in/out of - Tonicity – ability of a solution to move water in/out of a cell and change its shapea cell and change its shapea. Isotonic – osmotic pressure is = inside and outsidea. Isotonic – osmotic pressure is = inside and outsideb. Hypertonic – osmotic pressure is greater than within b. Hypertonic – osmotic pressure is greater than within the cell – water moves out of cell causing crenationthe cell – water moves out of cell causing crenationc. Hypotonic – osmotic pressure is less than within the c. Hypotonic – osmotic pressure is less than within the cell – water moves into the cell causing lysis.cell – water moves into the cell causing lysis.

4. Dialysis4. Dialysis

- form of diffusion in which the selectively permeable - form of diffusion in which the selectively permeable membrane separates large and small solute particlesmembrane separates large and small solute particles

5. Filtration5. Filtration

- passage of water and permeable solutes through a - passage of water and permeable solutes through a membrane by the force of hydrostatic pressuremembrane by the force of hydrostatic pressure

- small solutes pass down a hydrostatic pressure - small solutes pass down a hydrostatic pressure gradientgradient

- separates large and small solutes- separates large and small solutes

- happens most often in the capillaries- happens most often in the capillaries

- kidney function is dependent on blood pressure- kidney function is dependent on blood pressure

Active Transport ProcessesActive Transport Processes cell uses metabolic energy to move materials cell uses metabolic energy to move materials

1.1. Active TransportActive Transport

- carrier-mediated process that moves substances - carrier-mediated process that moves substances against their concentration gradientsagainst their concentration gradients

- opposite of diffusion- opposite of diffusion

- substances are moved by pumps which use ATP to - substances are moved by pumps which use ATP to change shape and move their cargoschange shape and move their cargos

- carrier proteins bind to cargo, change shape, and - carrier proteins bind to cargo, change shape, and release the cargorelease the cargo

2. Endocytosis and Exocytosis2. Endocytosis and Exocytosis

- allow things to enter and leave a cell without actually - allow things to enter and leave a cell without actually passing through the plasma membrane.passing through the plasma membrane.

A. Endocytosis – plasma membrane traps some A. Endocytosis – plasma membrane traps some extracellular material and moves it to the interior in a extracellular material and moves it to the interior in a vesicle.vesicle.

- Phagocytosis – large particles are engulfed - Phagocytosis – large particles are engulfed within a vesicle that then fuses with lysosomes to within a vesicle that then fuses with lysosomes to digest particlesdigest particles

- Pinocytosis – fluid and the substances - Pinocytosis – fluid and the substances dissolved in it enter the celldissolved in it enter the cell

3. Exocytosis3. Exocytosis

- process that cells use to expel large molecules, - process that cells use to expel large molecules, notably proteins for exportnotably proteins for export

- large molecules are first enclosed in membranous - large molecules are first enclosed in membranous vesicles which then fuse with the plasma membrane vesicles which then fuse with the plasma membrane and release their contents to the environment and release their contents to the environment surrounding the cell.surrounding the cell.

- also is how the smooth endoplasmic reticulum is - also is how the smooth endoplasmic reticulum is able to add new material to the plasma membraneable to add new material to the plasma membrane

Cytoplasm and OrganellesCytoplasm and Organelles

1.1. CytoplasmCytoplasm

- semifluid substance that occupies most of the cell - semifluid substance that occupies most of the cell interior = cytosolinterior = cytosol

- organelles are suspended in the cytoplasm and - organelles are suspended in the cytoplasm and attached to the cytoskeletonattached to the cytoskeleton

- contains nutrients, ions, and other raw materials - contains nutrients, ions, and other raw materials important to cell functioningimportant to cell functioning

- carries-out most of the properties of life- carries-out most of the properties of life

2. Endoplasmic Reticulum2. Endoplasmic Reticulum

- membranous-walled canals and flat sacs that - membranous-walled canals and flat sacs that extend from the plasma membrane to the nucleusextend from the plasma membrane to the nucleus

- important in the synthesis, modification, and - important in the synthesis, modification, and movement of materials within the cell movement of materials within the cell

A. Rough Endoplasmic ReticulumA. Rough Endoplasmic Reticulum

- has ribosomes attached to its’ surface- has ribosomes attached to its’ surface

- ribosomes make proteins which move into the - ribosomes make proteins which move into the cisternae of the ER and are transported cisternae of the ER and are transported

toward the Golgi apparatustoward the Golgi apparatus

B. Smooth Endoplasmic ReticulumB. Smooth Endoplasmic Reticulum

- lacks ribosomes- lacks ribosomes

- transports, synthesizes, and chemically - transports, synthesizes, and chemically modifies modifies small moleculessmall molecules

- synthesizes certain lipids and carbohydrates - synthesizes certain lipids and carbohydrates and and creates membranes for use throughout the creates membranes for use throughout the

cellcell

- helps in detoxification of poisons in the liver- helps in detoxification of poisons in the liver

- stores Ca++ in the muscle fibers- stores Ca++ in the muscle fibers

3.3. RibosomesRibosomes

- sites of protein synthesis – where amino acids are - sites of protein synthesis – where amino acids are joinedjoined

- many are attached to Rough ER; others are free in - many are attached to Rough ER; others are free in the cytoplasmthe cytoplasm

- composed of two nonmembranous structures which - composed of two nonmembranous structures which come together once a mRNA molecule attaches to the come together once a mRNA molecule attaches to the large subunitlarge subunit

- attach to the mRNA and move along it adding amino - attach to the mRNA and move along it adding amino acids as directed by the codeacids as directed by the code

- - subunits are composed of rRNA and proteinsubunits are composed of rRNA and protein

- attached ribosomes make proteins for export- attached ribosomes make proteins for export

- free ribosomes make proteins for intracellular use- free ribosomes make proteins for intracellular use

RibosomesRibosomes

4. Golgi Apparatus4. Golgi Apparatus

- series of flattened membranous sacs that modify protein - series of flattened membranous sacs that modify protein products of the rough endoplasmic reticulumproducts of the rough endoplasmic reticulum

- final products are packaged in vesicles which can then be moved - final products are packaged in vesicles which can then be moved to the cell membrane for exportto the cell membrane for export

- some of these vesicles remain in the cell as lysosomes - some of these vesicles remain in the cell as lysosomes

- can also give rise to new membrane structures for the cell- can also give rise to new membrane structures for the cell

5.5. LysosomesLysosomes

- digestive system of the cell- digestive system of the cell

- membranous sacs which pinch off the Golgi - membranous sacs which pinch off the Golgi apparatusapparatus

- contain hydrolytic enzymes which digest particles - contain hydrolytic enzymes which digest particles or large molecules that enter themor large molecules that enter them

- also responsible for digesting unneeded or - also responsible for digesting unneeded or unhealthy cells and cell partsunhealthy cells and cell parts

6.6. PeroxisomesPeroxisomes

- small membranous sacs which contain enzymes - small membranous sacs which contain enzymes that detoxify harmful substances that enter cellsthat detoxify harmful substances that enter cells

- common in kidney and liver cells- common in kidney and liver cells

Endomembrane System

7.7. MitochondriaMitochondria

- “power plants” of cells- “power plants” of cells

- double membraned organelle with fluid between the - double membraned organelle with fluid between the membranesmembranes

- lots of enzymes attached to both membranes- lots of enzymes attached to both membranes

- enzymes catalyze oxidation reactions of cellular - enzymes catalyze oxidation reactions of cellular respiration and capture the energy of sugars in the respiration and capture the energy of sugars in the bonds of ATPbonds of ATP

- provide 95% of the cell’s energy- provide 95% of the cell’s energy

- contain their own ribosomes and DNA and can - contain their own ribosomes and DNA and can replicate themselvesreplicate themselves

NucleusNucleus ““control center” of the cellcontrol center” of the cell Contains the chromosomes on which the genes are Contains the chromosomes on which the genes are

locatedlocated Fine threads called chromatin in nondividing cellsFine threads called chromatin in nondividing cells Condense into visible chromosomes during cell divisionCondense into visible chromosomes during cell division

Nuclear membrane has two parallel membranes with Nuclear membrane has two parallel membranes with nuclear pores penetrating themnuclear pores penetrating them

Nuclear pores allow mRNA to leave the nucleus to go Nuclear pores allow mRNA to leave the nucleus to go to the cytoplasmto the cytoplasm

Also contains the nucleolus where ribosomal subunits Also contains the nucleolus where ribosomal subunits are producedare produced

CytoskeletonCytoskeleton Internal support framework made up of rigid, rodlike Internal support framework made up of rigid, rodlike

proteins that support the cell and allow movement proteins that support the cell and allow movement and mechanisms that can move the cell or its partsand mechanisms that can move the cell or its parts

Acts as both muscle and skeleton for cellActs as both muscle and skeleton for cellA.A. Cell FibersCell Fibers

- form a three-dimensional support framework- form a three-dimensional support framework- support endoplasmic reticulum, mitochondria, and - support endoplasmic reticulum, mitochondria, and free ribosomesfree ribosomes1. Microfilaments – smallest fibers1. Microfilaments – smallest fibers

- cellular muscles that provide for movement- cellular muscles that provide for movement2. Intermediate filaments – form much of the support 2. Intermediate filaments – form much of the support network of the cellnetwork of the cell3. Microtubules – maintain cell shape and move 3. Microtubules – maintain cell shape and move things within the cellthings within the cell

B. CentrosomeB. Centrosome- coordinates the building and breaking of microtubules - coordinates the building and breaking of microtubules in the cellin the cell- centrioles are located within the centrosome- centrioles are located within the centrosome- during cell division makes the mitotic spindle- during cell division makes the mitotic spindle

C. Cell ExtensionsC. Cell Extensions- cytoskeleton forms projections that are covered by - cytoskeleton forms projections that are covered by the plasma membranethe plasma membrane1. Microvilli – increase the surface area in intestines 1. Microvilli – increase the surface area in intestines

and other areas for better absorptionand other areas for better absorption2. Cilia and Flagella – project from the surface of cells 2. Cilia and Flagella – project from the surface of cells

and allow cell movement or create movement and allow cell movement or create movement past past the cell surfacethe cell surface

- cilia are short and numerous; flagella long - cilia are short and numerous; flagella long

Cell MetabolismCell MetabolismMetabolismMetabolism- Sum of all of the chemical reactions in cellsSum of all of the chemical reactions in cells- Nearly all reactions are catalyzed by enzymesNearly all reactions are catalyzed by enzymes- Enzymes are specific in their actions as they work Enzymes are specific in their actions as they work

based on the shape of their active site and the shape of based on the shape of their active site and the shape of the substrates they work on.the substrates they work on.

- Enzymes work best under certain conditions and can Enzymes work best under certain conditions and can be denatured and made ineffective by changing those be denatured and made ineffective by changing those conditions – temperature and pHconditions – temperature and pH

CatabolismCatabolism Catabolism is the chemical reactions that break large Catabolism is the chemical reactions that break large

molecules into smaller molecules and often release molecules into smaller molecules and often release energyenergy

Cellular RespirationCellular Respiration- Process by which cells break down glucose into Process by which cells break down glucose into

carbon dioxide and watercarbon dioxide and water- Releases energy stored in the sugar and transfers it Releases energy stored in the sugar and transfers it

to the high energy bonds of ATPto the high energy bonds of ATP- Three main processes:Three main processes:

1. glycolysis – splits glucose into two pyruvic acid 1. glycolysis – splits glucose into two pyruvic acid moleculesmolecules

- happens in the cytoplasm and forms ATP - happens in the cytoplasm and forms ATP and and molecules that enter the molecules that enter the mitochondriamitochondria

2. Citric Acid Cycle = Krebs Cycle2. Citric Acid Cycle = Krebs Cycle

- happens in the matrix of the mitochondria and - happens in the matrix of the mitochondria and

breaks down the pyruvic acids from glycolysis breaks down the pyruvic acids from glycolysis

into COinto CO2 2 and other molecules that carry and other molecules that carry

protons protons

to the to the

3. Electron Transport Chain3. Electron Transport Chain

- series of proteins embedded in the inner - series of proteins embedded in the inner

membrane of the mitochondria which pass membrane of the mitochondria which pass

electrons from one to another and capture their electrons from one to another and capture their

energy in the bonds of ATPenergy in the bonds of ATP

- produce most of the ATP we use- produce most of the ATP we use

- Oxygen is the final electron acceptor- Oxygen is the final electron acceptor

AnabolismAnabolism- Constructive reactions in cells- Ultimately controlled by DNA- Genes in DNA control production of proteins- Gene = sequence of bases which control production of a polypeptide

Transcription and Translation = Protein Transcription and Translation = Protein SynthesisSynthesis

TranscriptionTranscription Making messenger RNA from one gene of Making messenger RNA from one gene of

the DNAthe DNA Base pairing rules assure that mRNA has Base pairing rules assure that mRNA has

correct sequence (A-U; C-G)correct sequence (A-U; C-G) Codon – sequence of three bases on Codon – sequence of three bases on

mRNA that code for an amino acid – each mRNA that code for an amino acid – each codon codes for a specific amino acidcodon codes for a specific amino acid

mRNA leaves nucleus through nuclear mRNA leaves nucleus through nuclear pores and attaches to ribosome where pores and attaches to ribosome where translation occurstranslation occurs

TranslationTranslation mRNA attaches to a ribosomemRNA attaches to a ribosome tRNA molecules bring specific amino acids to the tRNA molecules bring specific amino acids to the

mRNA at the ribosome – anticodon of tRNA base pairs mRNA at the ribosome – anticodon of tRNA base pairs with codon of mRNA which ensures that the correct with codon of mRNA which ensures that the correct amino acid is attached to the polypeptideamino acid is attached to the polypeptide

Peptide bonds join the amino acid to the growing Peptide bonds join the amino acid to the growing polypeptide chainpolypeptide chain

Enzymes then help fold the polypeptide and join it with Enzymes then help fold the polypeptide and join it with others to form functional proteins.others to form functional proteins.

Growth and Reproduction of CellsGrowth and Reproduction of Cells Growth and reproduction are fundamental Growth and reproduction are fundamental

characteristics of lifecharacteristics of life Cell growth uses DNA instructions to make structural Cell growth uses DNA instructions to make structural

and functional proteins needed for cell survivaland functional proteins needed for cell survival Cell reproduction ensures genetic information is Cell reproduction ensures genetic information is

passed from one generation to the nextpassed from one generation to the next

InterphaseInterphase Normal condition of a cellNormal condition of a cell Divided into three phasesDivided into three phases

1.1. G1 – First Gap PhaseG1 – First Gap Phase

- cell grows to “adult” size by manufacturing - cell grows to “adult” size by manufacturing cytoplasm and organellescytoplasm and organelles

- carries out normal functions- carries out normal functions

- variable length of time- variable length of time

- centrioles begin to replicate- centrioles begin to replicate

- chromosomes are single-stranded- chromosomes are single-stranded

2. Synthesis – S phase2. Synthesis – S phase

- DNA replication occurs- DNA replication occurs

- semi-conservative replication – each new double - semi-conservative replication – each new double strand is made of one new strand and one strand is made of one new strand and one old strandold strand

- replication is controlled by DNA polymerase- replication is controlled by DNA polymerase

- unzips DNA and breaks H-bonds between - unzips DNA and breaks H-bonds between strandsstrands

- base pairs free nucleotides to exposed - base pairs free nucleotides to exposed nucleotidesnucleotides

- doubled chromosomes are made of sister - doubled chromosomes are made of sister chromatids joined at their centromerechromatids joined at their centromere

3. G2 – Second Gap Phase3. G2 – Second Gap Phase

- cell is waiting and preparing to divide- cell is waiting and preparing to divide

MitosisMitosis

- normal process of cell division- normal process of cell division

- every cell ends up with the - every cell ends up with the same genetic informationsame genetic information

- four phases- four phases

1. Prophase1. Prophase

- chromosomes condense and become visible- chromosomes condense and become visible

- nuclear membrane dissolves- nuclear membrane dissolves

- centrioles move and begin to form spindle fibers - centrioles move and begin to form spindle fibers which stretch across the cell and which stretch across the cell and

attach to attach to centromeres of chromosomescentromeres of chromosomes

2. Metaphase2. Metaphase

- chromosomes are pulled and line up at the - chromosomes are pulled and line up at the equator of the cellequator of the cell

- a spindle fiber is attached to each side of the - a spindle fiber is attached to each side of the centromerecentromere

3. Anaphase3. Anaphase

- centromere of each chromosome has split- centromere of each chromosome has split

- each chromosome is pulled toward the nearest - each chromosome is pulled toward the nearest polepole

- forms two separate identical pools of genetic - forms two separate identical pools of genetic materialmaterial

4. Telophase4. Telophase

- DNA unravels to form chromatin- DNA unravels to form chromatin

- nuclear membrane reforms- nuclear membrane reforms

- spindle breaks down- spindle breaks down

CytokinesisCytokinesis

- division of the cytoplasm- division of the cytoplasm