Cell membrane zThin, flexible, and somewhat elastic zSelectively Permeable y Allows some things in/out but not others yWhat are some things that are selectively permeable? zSignal Transduction y Helps signals from outer environment get into the cell
Cell Membrane Structure zDouble layer of phospholipid molecules. The water soluble head (phosphate group) forms the surface. The insoluble tail (fatty acid chain) is inside the layers. zWhat types of particles could easily pass through (solubility)?
Cell Membrane zFibrous proteins yProvide structure for the cell membrane, make it more rigid. zGlobular proteins yCalled integral proteins/transport proteins imbedded in the interior. yThey span the membrane channel allowing small molecules inside (may be a pore)
Cytoplasm zThe fluid that makes up the entire interior of the cell. zOrganelles are suspended in it. zProvides an area for reactions to occur, supports the cell with osmotic pressure
Endoplasmic Reticulum zER membrane is membrane-bound flattened sacs, elongated canals, and fluid filled vesicles. zPlays a role in protein and lipid synthesis. zTransports molecules throughout the cell. zAttachment site for ribosomes
Ribosomes zFound on the ER and floating in the cytoplasm zcomposed of protein and RNA zWhat is it’s function?
Golgi Apparatus zComposed of a stack of 6 cisternae zRefines, packages, and delivers proteins synthesized by the ribosomes zWhy do think proteins would need refining?
Mitochondria zElongated fluid filled sac zMoves slowly through the cytoplasm zReproduce by dividing zContains small amounts of DNA zHas an outer and inner membrane layer.
Mitochondria zThe enzymes and the mitochondria control many of the chemical reactions that release energy. zWhat are the molecules the mitochondria produce? zWhat are the substances mitochondria utilize to produce cellular energy?
Mitochondria zA typical cell will have about 1700 mitochondria. zWhat types of cells would have more mitochondria?
Lysosomes zThe cell’s garbage disposal. zCommonly appear as tiny membranous sacs that contain powerful enzymes that break down protein, carbohydrates, and nucleic acids as well as foreign particles zThey also destroy worn cellular parts.
Peroxisomes zThe outer membrane of a peroxisome contains 40 enzymes that perform various duties: ysynthesis of bile acids ybreakdown of lipids ydegradation of rare biochemicals ydetoxification of alcohol
Cilia & Flagella zCilia occur in large numbers on the surface of some epithelial cells. zCilia are tiny hairlike structures yUsed to move substances along the membrane zFlagella are tail-like structures that aid in cell motility zWhy would cells have cilia instead of flagella?
Cytoskeleton zMicrotubules yProvide passage ways to transport substances throughout the cell ySimilar to blood/lymphatic vessels in the body zMicrofilaments yProvide a framework of support for the cell ySimilar to bones in the body
Nucleus zDirects the activities of the cell. zEnclosed by a double-layered nuclear envelope. zNuclear envelope consists of an inner and outer lipid bilayer membrane.
Nucleolus zSmall, dense body composed largely of RNA and protein. zNo surrounding membrane. zSite of ribosome production. zCells may have more than one nucleolus.
Chromatin zConsists of loosely coiled fibers in the nuclear fluid zStores DNA and Forms chromosomes during cell reproduction zComposed of DNA
Movement of substances zDiffusion yMoves from high concentration to low. yOsmosis – diffusion of water yNo energy needed zFacilitated Diffusion yBig substance, still goes from high to low yUses proteins yNo energy needed
Active Transport zMovement of large particles by carrier proteins from low concentration to high concentration. zDoes it require Energy? zIt may use as much as 40% of a cell’s energy supply.
Active Transport zActive transport is similar to facilitated diffusion. zWhat’s the difference? zFig 3.16 page 62
Solute pumps zTransport amino acids and most ions zSodium-potassium pump yEssential for nerve impulses yWhy could transporting ions create an electrical impulse?
Endocytosis & Exocytosis zMolecules or particles too large to pass through the membrane by diffusion are actively transported into (endocytosis) and out of (exocytosis) the cell.
Cellular Processes zThe cell depends on proteins more than any other compound zFor this reason the cell has it’s own method of creating proteins that it needs zProtein Synthesis yBroken into two parts: zTranscription (DNA -> RNA) and Translation (RNA -> Protein)
Transcription zProducing a strand of messenger RNA (mRNA) from the DNA strand zmRNA uses one strand of DNA and is complementary to that DNA yExcept in RNA Uracil (U) takes the place of Thymine (T) zRNA polymerase moves along DNA strand and adds nucleotides to mRNA strand
Transcription zOccurs in the nucleus zWhen finished: yDNA winds back up ymRNA is sent out of nucleus to be used for translation zmRNA now contains instructions on how to build protein (codons)
Translation zBuilding the protein from the mRNA strand zDone at the ribosome zCodons used to indentify amino acid sequence zAll three types of RNA must come together to build the protein yrRNA prepares ribosome ytRNA brings amino acid (contains anticodon) ymRNA brings the instructions
Translation ztRNA brings amino acid and binds to mRNA zEnzymes remove the amino acid from that tRNA and attach it to the growing chain zWhen complete: yThe A.A. chain is released from the ribosome, folds and becomes a protein yThe mRNA and ribosome is reused to make more of the same protein
Metabolism zWhat does metabolism mean to you? zThe sum/total of all chemical reactions within the cell. zThere are two types of metabolic reactions: yAnabolism yCatabolism yWhat do you think each one means?
Anabolism zWhere have you heard anabolic before? zAnabolism- larger molecules are constructed from smaller ones, requiring the input of energy zAnabolic metabolism provides all substances required for cellular growth and repair.
Catabolism zProcess of breaking down larger molecules into smaller ones. zWhat will the breaking down of larger molecules do? zProvide Energy! yAn example of catabolic metabolism is digestion zWhat can be said about weight gain/loss and the balance between catabolism and anabolism?
Metabolic Rates zBasal metabolic rate - the amount of energy expended when the body is at rest zBMR for an average adult (155 lbs) y60-72 Cal/hour yWhat are factors that affect the BMR? zSurface area, Age, Gender, Emotions zTotal Metabolic Rate – Total calories the body must consume to fuel activities ySmall increases in muscular activity causes large jumps in TMR
Enzymes zMetabolic reactions must be carefully controlled! yHow are these controlled? zENZYMES! yMost reactions will not occur without them zEnzymes are required in only small amounts yWhy might this be? zThey are not used up during the reaction. yDoes one enzyme control all reactions? zNo, enzymes only act on a particular rxn. y One that contains their substrate.
Enzymes zHow does an enzyme recognize its substrate? zShape – the way the enzyme is folded zThe enzyme then binds to the substrate at the active site zThis is the action that causes the reaction to occur and the cell to metabolize substances yExample: lock and key
Cancer zCells that divide uncontrollably zWhy? yOncogene yTumor-suppressor gene zOncogenes must be turned on while tumor-suppressor genes are turned off yMutations cause this to happen
Cancer zWhat are mutations caused by? zUsually not caused by genetic errors a person is born with. yBut you can be genetically more susceptible yWhat does this mean? zPrimary Cause - Carcinogens yRadiation – from radioactive materials, UV, etc. yChemicals – Pollutants, tobacco, consumer products
Stages of Cancer zHyperplasia - first abnormal growth yExcess of normal appearing cells zDysplasia - cells begin to appear abnormal zLocalized cancer - ball of abnormal cells and blood nourishment yA.K.A Tumor zTwo types of Tumors yBenign - will not spread to surrounding tissues yMalignant – will spread to other tissue
Stages of Cancer zIf Malignant: zInvasion into adjacent tissue zMetastasis - invasion of lymph and blood vessels yLeads to spreading to other parts of body zLet’s say colon cancer spreads to the lungs, what type of cancer is it? zStill considered colon cancer because it still shows same abnormalities and characteristics as original
Most common causes of death due to cancer zWomen Lung25% Breast17% Colon/rectum10% Leukemia/Lymphoma 8 Ovary6 Pancreas5 Uterus/cervix5
Most common causes of death due to cancer zMen Lung32% Prostate14% Colon/rectum9% Leukemia/Lymphoma 9% Kidney/Bladder5% Pancreas5%
Why is Cancer so serious zAs a tumor gets larger, it will begin to grow its own blood supply zThis steals nutrients and oxygen, eventually choking off surrounding tissues zSurrounding tissues then begin to fail
Treatment z3 most common zSurgery yUsusally best option yda Vinci surgical systemda Vinci surgical system zRadiation yInternal and external yUsed to shrink tumor, usually combined with other treatments zChemotherapy-anticancer medicine yTargets all fast growing cells yDelivered to all body tissues yProblem?
Treatment zVaccine - HPV (human papillomavirus) causes most cervical cancer cases zHormone therapy zGene therapy