Popular in THE HUMAN BODY
Popular in Biological Sciences
This 25 page Study Guide was uploaded by Haley Genchur on Friday December 18, 2015. The Study Guide belongs to 805.0 at University of Pittsburgh taught by Swigonova,Zuzana in Fall 2015. Since its upload, it has received 25 views. For similar materials see THE HUMAN BODY in Biological Sciences at University of Pittsburgh.
Reviews for Exam 1
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 12/18/15
LECTURE 1: WHAT IS LIFE Hierarchy of Life atom: the smallest unit of an element composed of protons, neutrons, and electrons molecule: union of two or more atoms of the same or different elements cell: the smallest structural and functional unit of all living things tissue: group of similar cells that have the same structure and function organ: composed of tissues functioning together for a specific task organ system: composed of several organs working together organism: collection of organ systems population: organisms of the same species in a particular area community: interacting populations in a particular area ecosystem: a community plus the physical environment biosphere: regions of the Earth's crust, waters, and atmosphere inhabited by living organisms The Characteristics of Life 1. Made of Cells (Organized) 2. Acquire Materials and Energy 3. Maintain Homeostasis 4. Respond to Stimuli 5. Reproduce and Grow 6. Pass Hereditary Information to Offspring Name a Biological Entity that does Not Fall into the Category of Living Organisms Viruses: capsule made of proteins but don't have membranes (not made of cells); also need a host to reproduce (cannot reproduce alone) Prions: (proteins) 1. Made of Cells/Organized Cells are the basic structural and physiological units of all living organisms Cells are both distinct entities and building blocks of more complex organisms Hierarchy of Life 2. Acquire Materials and Energy Photosynthesis, Respiration, Fermentation, Metabolism, Anabolism, Catabolism Metabolism= all the chemical reactions that occur within a cell ATP=energy of a cell We need oxygen for energy, it allows us to generate more ATP that is required for the energy transformation process 3. Maintain Homeostasis Homeostasis= the ability of a cell or an organism to maintain an internal environment that operates under specific conditions All the systems of the human body help maintain homeostasis EX. heart rate (7080 bpm), blood pressure (120/70), body temperature (98.6), amount of water in the body, blood sugar Why do you cover yourself with a blanket when sleeping? Your metabolism slows down at night>temp slows down, in heaviest sleep when temp is lowest, temp highest before going to sleep *A high fever in the morning is reason to worry 4. Respond to Stimuli External (visual; phobia; phototropism when plant placed at window, loud noise, hot stove) vs Internal (blood clotting; hunger) 5. Reproduce and Grow Fertilization, Zygote, Growth, Development Reproduce= pass on genetic information to the next generation Growth= increase in size and often number of cells Development= all the changes that occur from the time the egg is fertilized until death Information in DNA contained in genes 6. Pass Hereditary Information to Offspring Evolution occurs in populations (we are not evolving) DNA= deoxyribonucleic acid, contains genetic information of all life Genes= contain the DNA, short sequences of hereditary material that specify the instructions for a specific trait Mutation= basis of evolutionary change! Evolution: process by which a population changes over time...occurs through natural selection...when a new variation arises that is beneficial, those members tend to survive and have more offspring, therefore each generation will have more members with that variation which represents an adaptation to the environment The Tree of Life: Humans are Related to Other Animals: The Three Domains 1. Bacteria: contain prokaryotes (onecelled organisms that lack a nucleus) 2. Archaea: contain prokaryotes (onecelled organisms that lack a nucleus) 3. Eukarya: Contain cells that possess a nucleus, some are singlecelled, others are multicellular 1. Bacteria Prokaryotic cells of various shapes Adaptations to all environments Absorb, photosynthesize, or chemosynthesize food 2. Archaea Prokaryotic cells of various shapes Adaptations to extreme environments Absorb or chemosynthesize food 3. Eukarya Divided into one of four kingdoms: plants, fungi, animals, and protists Eukarya: Kingdom Plants Certain algae, mosses, ferns, conifers, and flowering plants Multicellular, usually with specialized tissues, containing complex cells Photosynthesize food Eukarya: Kingdom Fungi Molds, mushrooms, yeasts, ringworms Mostly multicellular filaments with specialized, complex cells Absorb food Eukarya: Kingdom Animals Sponges, worms, insects, fish, frogs, turtles Multicellular with specialized tissues containing complex cells Ingest food Most organisms in this kingdom are invertebrates (worms, etc); vertebrates are animals that have a nerve cord protected by a vertebral column *Humans did NOT evolve from apes> humans and apes share a COMMON ANCESTOR *Humans: highly developed brain, abstract thinking, upright stance, creative language, usage of a variety of tools LECTURE 2: HOW SCIENTISTS WORK Science A way of knowing about the natural world, aim is to be objective Scientific Method Provides a general framework for how scientists study the world around them 1. Observation 2. Scientific Question 3. Hypothesis 4. Prediction 5. Experiment 6. Conclusion 1. Observation New observations are made and previous data are studied 2. Scientific Question The problem at hand..."can this happen? How can we prevent/cause this?" 3. Hypothesis This is the cause of that...the answer you think you'll find...possible explanation for a natural event, based on existing knowledge. A testable statement Can a hypothesis be proven true? NO, only supported ex "Antibiotic B is a better treatment for ulcers than antibiotic A" 4. Prediction A prediction of what the results will be..."based on the hypothesis, this will be seen" ex. "based on all cells from cells theory, only cells detected in one flask with exposure to preexisting cells" 5. Experiment The hypothesis is tested by experiment or further observations Keep all conditions constant except for experimental variableaka independent variable (manipulated), also has a dependent variable (measured) test groups: exposed to the experimental variable, manipulated in an experiment, receives identical treatment as other groups except for one variable control groups: not exposed to experimental variable, not manipulated in an experiment, used as a foundational point for comparison, might receive a placebo 6. Conclusion The results are analyzed and the hypothesis is supported or rejected the uncertainty of data is called standard error Case Study 1: The Childbed Fever Dr. Semmelweis, Vienna General Hospital 1. Observation: Semmelweis observed the high death rate (20% of patients in Division I dying after childbirth) 2. Scientific Question: Why was there a much higher mortality rate in DI? 3. Hypothesis: Semmelweis claimed that bacteria (contamination from cadavers) was the cause of the higher death rate in DI. 4. Prediction: If medical doctors would wash their hands with chlorinated lime, the death rate would decrease in DI. 5. Experiment: Enforce strict hand washing policy amongst male medical students and colleagues in DI, all required to wash with chlorinated lime water before attending patients. 6. Conclusions: When male physicians washed their hands, the mortality rate in DI dropped significantly. This supports the hypothesis that bacteria (contamination from cadavers) was the cause of the higher death rate in DI. Louis Pasteur and the Cell Theory Louis Pasteur, founder of microbiology Spontaneous generation hypothesis: things/cells appear from nowhere (wrong) Allcellsfromcells hypothesis: cells come from preexisting cells 1. Observation: Noticed cells appearing 2. Scientific Question: Can microorganisms arise spontaneously in a nutrient broth or do they appear only when a broth is exposed to a source of preexisting cells? 3. Hypothesis: Pasteur claimed all cells come from cells...cells cause other cells to appear. 4. Prediction: Based on allcellsfromcells theory, cells will only be detected in a broth that has exposure to preexisting cells. 5. Experiment: Two treatment groups: one with exposure to source of preexisting cells and one without, used swanneck flasks to investigate whether cells arise spontaneously. 6. Conclusions: Cells arise from preexisting cells, not spontaneously from nonliving material. Robert Koch and the Germ Theory To establish a causal relationship between a microorganism and an infection, Koch's postulates must be fulfilled: 1. The microorganism must be detectable in the infected host at every stage of the disease 2. The microorganism must be isolated from the diseased host and grown in pure culture 3. When susceptible, healthy animals are infected with pathogens from the pure culture, the specific symptoms of the disease must occur 4. The microorganism must be reisolated from the now diseased animal and correspond to the original microorganism in pure culture Barry Marshall and the Cause of Stomach Ulcers Claimed stomach ulcers are caused by H. pylori, not stress! H. pylori survives stomach acid and neutralizes the environment around them Hypothesis: Ulcers are caused by bacterium H. pylori How did Dr. Marshall apply Koch's postulates? 1. Microorganism H. pylori detected in host 2. H. pylori isolated from diseased host and grown in pure culture 3. Subjected himself!! Drank H. pylori, experienced exact symptoms 4. Made complete link between disease and causative agent! Controlled Study: Which of Two Antibiotics Best Treats an Ulcer? Hypothesis: Newly discovered antibiotic B is a better treatment for ulcers than antibiotic A, which is in current use. 3 experimental groups: one control group and 2 test groups Reduce number of possible variables among groups such as age, gender, health, etc...randomly divide All subjects in experiment must sign consent, have symptoms, and think they all receive the same treatment Control group: subjects with ulcers are not treated with either antibiotic, received placebo Test group 1: Subjects with ulcers are treated with antibiotic A Test group 2: Subjects with ulcers are treated with antibiotic B Collect data: each subject was examined for the presence of ulcers, endoscopic examination, doubleblind study (neither patient nor technician aware of specific treatment) Conclusion: Hypothesis supported: antibiotic B is a better treatment for ulcers than antibiotic A. LECTURE 3: CHEMISTRY OF LIFE Atoms the smallest unit of an element that still retains the chemical and physical properties of the element: most simplistic particle of living biomass Subatomic particles: Protons (+) and Neutrons (0) in nucleus, and Electrons () moving about nucleus in electron shell atoms are neutral (protons and electrons cancel, always have the same number) most of an atom is empty space Practical Atom Drawing 1st energy shell: MAX 2 electrons 2nd energy shell: MAX 8 electrons Best to have inner shells at 2 and outer shells at 8 to make a happy atom (mosts stable when shells are full) outer shell is called the valence shell The Periodic Table atomic symbol: H, Fe, Cl atomic number: the number of protons in the nucleus; all atoms of an element have the same number of protons in the nucleus mass number: the sum of the protons and neutrons in the nucleus; each atom has its own mass number depending on the number of subatomic particles in that atom atomic mass: (number with decimals) is the average of the AMU for all the isotopes of that atom *to determine the number of neutrons, take the number of protons and subtract that from the atomic mass, round to the nearest whole number Isotopes Protons and electrons in an atom are always the same, but neutrons can differ> isotope isotopes of the same atom have the same number of protons (same atomic number) but different numbers of neutrons (different mass numbers) Can determine the number of neutrons for an isotope by subtracting the atomic number for that element from the mass number (ex. C14 has 8 neutrons because carbon's atomic number is 6) Radioisotopes release various types of energy in the form of rays and subatomic particles behaves the same chemically as the stable isotopes of an element> becomes a tracer, radiation can be good (safety of food) or bad (radioactive substances in environment) used to make tracers and radioactive labels or to kill bacteria and viruses Molecules oxygen (O2): means 2 atoms in oxygen molecule carbon dioxide (CO2): means 1 carbon, 2 oxygen molecule: formed by atoms bonding with one another, can contain atoms of the same type or atoms can be different When the atoms joined are different, acompound is formed Ionic Bonding During an ionic reaction, atoms give up or take on an electron or electrons to achieve a stable valence shell ions: particles that carry either a positive or a negative charge positive charge: more protons than electrons negative charge: more electrons than protons The attraction between oppositely charged sodium ions and chloride ions forms an ionic bond Complete transfer of electrons: taking and giving away the strong attraction of opposite charges holds the bond together ex. NaCl Covalent Bonding Atoms share electrons overlapping outermost shells each atom contributes one electron to theshared pair electrons belong to both bonded atoms single bond: atoms share one pair of electrons (2 total in the middle) double bond: atoms share two pairs of electrons (4 total in the middle) triple bond: atoms share three pairs of electrons (6 total in the middle) structural formula: O=C=O (each line represents a pair of shared electrons) molecular forumla: CO2 A covalent bond in which electrons are NOT shared equally is called a polar covalent bond Atoms Combining into Molecules Law of Conservation of Mass: when chemical bonding occurs there is no matter lost; matter is neither created nor destroyed in a chemical reaction Water Life cannot exist without water Animals and plants made up of 7090% water Aquatic organisms do not need such a retention of water as land organisms Retention of water developed as an adaptation essential for life in dry land environment Water essential for structure and function of a living organism Water: Polar Water is a polar molecule (hydrogen bonds): attracts others that have charge (hydrophilic) Ability of ice to float, melting and freezing temperatures, water stores heat, forms water droplets In water, the electrons spend more time circling the oxygen atom than the hydrogens because oxygen has a greater ability to attract electrons than do the hydrogen atoms Negatively charged electrons are closer to the oxygen atom, so the oxygen atom becomes slightly negative Hydrogens are slightly positive the partial charge allows hydrogen bonds to form temporarily between water molecules BASICALLY the bonds between water molecules are hydrogen bonds but the bonds between oxygen and hydrogen atoms are covalent bonds Hydrogen Bonds the attraction of a slightly positive, covalently bonded hydrogen to a slightly negative atom in the vicinity usually occur between a hydrogen and either an oxygen or nitrogen atom dotted line, relatively weak, can be broken easily responsible for water being a liquid at temperatures typically found on the Earth's surface What they lack in strength, they make up for in abundance Polar Covalent Bonds a bond where electrons are unequally shared, resulting in more electrons orbiting certain atoms than others (electrons orbit oxygen more than hydrogen) Water Orientation Each oxygen atom (negative charge) will be opposite two hydrogen atoms (positive charge)> hydrogen bond generated Properties of Water 1. Water Has a High Heat Capacity 2. Water Has a High Heat of Evaporation 3. Water is a Solvent 4. Water Molecules are Cohesive and Adhesive 5. Frozen Water is Less Dense than Liquid Water 1. Water Has a High Heat Capacity calorie: amount of heat energy needed to raise the temperature of 1 gram of water 1 degree Celsius Great capacity to absorb and retain heat hydrogen bonds help water to absorb heat without a great change in temperature temperature of water rises and falls slowly, better able to maintain our internal temperature (homeostasis) and we are protected from rapid temperature changes Temps along coasts are moderate: Oceans absorb and store heat in the summer and slowly release it during the winter 2. Water Has a High Heat of Evaporation hydrogen bonds must be broken before water boils gives our bodies an efficient way to release excess body heat in a hot environment Sweating 3. Water is a Solvent Dissolves a great number of substances, especially those that are also polar Facilitates chemical reactions both outside and within living systems solution contains dissolved substances which are then called solutes Example: when ionic compounds are put into water (NaCl ex.) the negative ends of the water molecules are attracted to the sodium ions and the positive ends are attracted to the chloride ions: dissociate in water hydrophilic: molecules that can attract water (polar) hydrophobic: molecules that cannot attract water (nonpolar) (ex. oil and water) 4. Water Molecules are Cohesive and Adhesive Cohesion: the ability of water molecules to cling to each other during hydrogen bonding; surface tension created Adhesion: the ability of water molecules to cling to other polar surfaces At any time a water molecule can form hydrogen bonds with up to four other water molecules 5. Frozen Water is Less Dense than Liquid Water Ice floats on liquid water: allows life to flourish under the ice As liquid water cools, molecules come closer together What will happen with a glass jar full of water left in the winter outside your house? All 4 bonds will form and the glass will break Acids and Bases When water molecules dissociate (break up) they release an equal number of hydrogen ions (H+) and hydroxide ions (OH) pH value of water is 7 (10 to the 7 power) Water acts as a weak acid and a weak base Acidic Solutions acids: substances that dissociate in water, releasing hydrogen ions (H+) proton donor lemon juice, vinegar, tomatoes H+ concentration is greater than the OH concentration Basic Solutions bases: substances that either take up hydrogen ions (H+) or release hydroxide ions (OH) proton acceptor bleaches, soaps, toothpaste, baking powder, cleaners OH concentration is greater than the H+ concentration pH Scale used to indicate the acidity or basicity (alkalinity) of a solution ranges from 0 to 14 06 acidic, 7 neutral (H+ and OH are equal) , 814 basic as we move up the scale from 014, each unit is 10 times more acidic than the previous unit Why does pH Matter? Living things function best in a nearneutral (pH 68) although some systems in living things have different pH requirements (interior of stomach pH as low as 1, blood in arteries pH about 7.4) Constant pH of the environment is required for proper functioning (enzyme changes its shape when exposed to too acidic solutions, disruption of cell membrane due to pH usually results in cell death) Organisms have developed acidbase buffering systems Buffers pH stability is possible because the body and the environment have buffers to prevent pH changes Buffers help keep the pH within normal limits because they are chemicals or combinations of chemicals that take up excess H+ or OH LECTURE 4: MOLECULES OF LIFE Four Categories of Organic Molecules 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids All unique to cells Know each one's function in relation to cell, tissue, and the organism Organic= molecule containing carbon and hydrogen, associated with living organisms Substances Found in Living Tissues Mostly water, followed by macromolecules, then ions and small molecules Regarding macromolecules: mostly proteins, followed by nucleic acids, followed by carbs and then lipids Macromolecules macromolecule: (carb, lipid, proteins, nucleic acid) contains many subunits dehydration reaction: type of synthesis reaction> constructing a macromolecule. During a dehydration reaction, a OH and an H (the equivalent of a water molecule)(H20) are removed as the molecule forms hydrolysis reaction: breaking downmacromolecules, components of water are added during the breaking of the bond between the molecules Carbohydrates presence of the atomic grouping HCOH, where the ratio of hydrogen atoms H to oxygen atoms O is 2:1 function for quick and short term energy storage simple, immediate source of energy Complex: modified before the body can use, some structural some storage Sugars Simple Carbohydrates Monosaccharide: carbohydrate made up of just one ring and number of carbon atoms is between 5 and 7, nonbranched glucose, fructose (fruits), galactose (milk), deoxyribose glucose: primary energy source for brain cells, C6H12O6, immediate source of energy, ex. apple Disaccharide: made by joining only two monosaccharides together by a dehydration reaction sucrose, lactose Complex Carbohydrates Polysaccharides: contain many glucose units, branched starch, glycogen, cellulose, chitin Starch: slower energy release (ex. bagel), readily stored form of glucose in plants, fewer side branches/chains, potatoes/corn/wheat, glucose enters bloodstream and the liver stores glucose as glycogen (must be transformed/broken down) Glycogen: readily stored form of glucose inanimals, more side branches/chains, liver/muscles Structural Carbohydrates (Fiber in the Diet) Soluble and Insoluble Fiber Fiber is mainly composesd of the undigested carbs that pass thorugh the digestive system Most fiber derived from plants Not a nutrient Soluble Fiber: pectin, gum, fruits/oat grains/nuts, forms gellike paste that softens stool/dissolves in water Slows down digestion, stays there longer, thus increases absorption and the feeling of fullness Binds cholesterol and facilitates its removal from the body, does not contribute to glucose levels in the body Insoluble Fiber: lignin, cellulose, wheat bran/nuts/seeds/fruit skin/brown rice/veggies, bulk of fecal material, attracts water and makes stool softer, faster moving through the digestive system Note on cellulose: found in plant cell walls, unable to digest: largely passes through our digestive tract as fiber or roughage Lipids Common lipids: fats, oils, cholesterol, hormones C, H, O Do NOT readily dissolve in water: hydrophobic (made of carbon and hydrogen which are nonpolar molecules) Do NOT possess the monomerstopolymers structure seen in other biological molecules; no one structural element is common to all lipids (no simple general structure) FUNCTION: Energy (most energyrich molecule for the body), cushioning and insulation, components of cellular membranes (phospholipids), padding around structures and internal organs Fats & Oils fats: usually of animal origin, solid at room temperature oils: usually of plant origin, liquid at room temperature a fat is sometimes called a triglyceridebecause of its threepart structure: made of glycerol (core of molecule) and three fatty acids; dehydration reaction, formed when three fatty acids combine with glycerol by dehydration synthesis reactions. The reverse reaction starts the digestion of fat; hydrolysis introduces water, and fatty acidglycerol bonds are broken fatty acid: a carbonhydrogen chain that ends with the acidic group COOH. Either saturated or unsaturated Saturated Fats saturated fatty acids: have no double bonds between the carbon atoms, chain is saturated with all the hydrogens it can hold, naturally occurring, solid at room temperature Unsaturated Fats unsaturated fatty acids: have double bonds in the carbon chain wherever the number of hydrogens is less than two per carbon, naturally occurring, liquid at room temperature Saturated and Unsaturated Fats Differ..... In the number of hydrogen atoms present Trans Fats trans fats: most harmful, not natural, bonds difficult to break, accumulate in the circulatory system, lower HDLs (good; carry cholesterol away from heart) and increase LDLs (bad; carry cholesterol toward heart), increase risk of cardiovascular disease, double bond but solid at room temperature, have long tails Phospholipids composed of TWO fatty acids, glycerol, and a phosphate group constructed like fats except that in place of the third fatty acid there is a phosphate group or a grouping that contains both phosphate and nitrogen NOT electrically neutral like fats are primary components of cellular membranes, form a bilayer, hydrophilic heads and hydrophobic tails nonpolar faces nonpolar, polar faces polar Steroids lipids that have entirely different structure from those of fats contain 4ring structure (backbone of four fused carbon rings) testosterone and estrogen: sex hormones cholesterol: component of cell membranes, used to manufacture sex hormones above! Proteins STRUCTURE and FUNCTION (not energy) HUGE variety of functions! Support, Enzymes, Transport, Defense, Hormones, Motion Types of proteins: enzymes, hormones, transport, contractile, protective, structural, storage, toxins, communication Examples: sucrase, growth hormone, hemoglobin, myosin and actin, antibodies, keratin/collagen, glycoproteins TRUE: the tertiary structure of a protein has many different types of bonds, the primary structure of proteins are held together by peptide bonds, a protein's structure is closely related to its function FALSE: all hormones are protein based (not true!!), proteins are made up of an amino group, a carboxyl group, a side chain, a hydrogen and a carbon (no carbon) Amino Acids: Subunits/Building Blocks of Proteins proteins are macromolecules with amino acid subunits 20 unique amino acids Structure of amino acid: made of a hydrogen, an amino group (h3n+), a side chain (R), and a carboxyl group (COOH) The sidechains attached to the central carbon (R) make amino acids unique! (amino acids differ according to their particular R group): some R groups are polar, some are not All 20 are the same but differ in the side chain (R) Synthesis of Proteins Dehydration Reaction peptide bond: the covalent bond between two amino acids polypeptide: when three or more amino acids are linked by peptide bonds, the chain that results is a polypeptide the atoms associated with the peptide bond share the electrons unevenly because oxygen attracts electrons more than nitrogen: the hydrogen attached to the nitrogen has a pos charge while the oxygen has a neg charge How many peptide bonds are in this protein? N1! Number of balls minus 1 is the answer Structure of Proteins/Levels of Organization Primary: sequence of amino acids (peptide bond) Secondary: alpha helix or a pleated sheet (hydrogen bond) Tertiary: final shape of polypeptide (helix and sheets fold; hydrogen and ionic bonds, disulfide bond) Quaternary: two or more associated polypeptides Basically there are a variety of chemical bonds that stabilize the structure The function of a protein is determined by its correct structure Examples of Proteins (small at top, biggest at bottom) Insulin (regulation of glucose in blood stream) Hemoglobin (transport oxygen in red blood cells) CFTR (related to cystic fibrosis) Titin (responsible for passive elasticity of muscles) Changes in Structure Result in Loss of Function Protein conformation (structure) is stabilized by a variety of chemical bonds and attractions (there are many different bonds and attractions that stabilize the structure of a protein) denaturation: loss of structure/irreversible change in shape, occurs because the normal bonding between the R groups has been disturbed, can no longer perform its usual function (Alzheimer's disease) Nucleic Acids 2 Types: RNA and DNA They differ structurally: RNA is a functional nucleotide and single stranded, while DNA contains hereditary info, double helix, in the nucleus Nucleotide: made of sugar, phosphate group, and nitrogencontaining base, it is the structural monomer of nucleic acid: building block of DNA and RNA the sugar can be deoxyribose or ribose and the base can be pyrimidine or purine DNA VS. RNA DNA: sugar is deoxyribose, double stranded (held together by hydrogen bonds) hereditary information in the nucleus, ACGT (T with A, G with C) RNA: sugar is ribose, usually single stranded, messenger for proteosynthesis, transfer molecules, regulatory molecules, ACGU ATP: An Energy Carrier When adenine (A) plus ribose is modified by the addition of three phosphate groups instead of one, it becomes ATP which is an energy carrier in cells and a high energy molecule because the last two phosphate bonds are unstable and easily broken ATP is used to attach the phosphate group Structure suits its function With inorganic phosphate: ADP *ATP is composed of the base adenosine and three phosphate groups (called a triphosphate). When cells need energy, ATP is hydrolyzed (water is added) forming ADP and P. Energy is released. Question: Which describe chemical processes that results from dehydration reaction? Formation of starch from glucose molecules, production of a triglyceride from glycerol and three fatty acids, amino acids making an enzyme LECTURE 5: THE CELL The Cell Theory All living organisms are made up of cells Cell is a fundamental unit of life Nothing smaller than a cell is considered to be alive Structure of a cell is directly related to its function New cells arise only from preexisting cells reproduction, metabolism, response to stimuli, homeostasis, genetics, evolution What Limits the Cell Size? Most cells are small. Why? Prokaryotic cell 110 um, Eukaryotic cell 5100 um Explained by the surface area to volume ratio of cells The greater the amount of surface, the greater the ability to get material into and out of the cell As cell size decreases, the surface area decreases and the surface area to volume ratio increases As cell size increases, volume increases more (faster) than the surface area. A small cell has a greater surface area to volume ratio (ex. 0.6) than a large cell (ex. 0.3) A cell needs a higher surface area to volume ratio to get stuff done Cells can't function beyond a certain size Small surface area to volume ratio=less exchange through the surface area, not good for the cell Surface<>Transport, Volume<>Metabolism Bacterial Cell singlecelled, Prokaryotic (lacking a nucleus) Things unique to a bacterial cell: capsule(protects from harmful things in environment) flagellum (propelling cell in the environment/movement) , and cell wall(it has 2 membranes) No membranebound organelles Dependent on conditions in environment Specialized Features of Some Prokaryotic Cells Cell wall (gram positive/gram negative) Internal membranes (cyanobacteria: need large surface area; proteins in photosynthesis) Flagella and pili (movement; facilitate attachment of bacterium to substrate) Cytoskeleton (simpler, protein fibers inside cell, determine shape, actin based) Eukaryotic Cell 10x larger than prokaryotic cells Unlike prokaryotic cells, eukaryotic cells contain membranous compartments (organelles) Nucleus Mitochondrion Endoplasmic Reticulum (smooth and rough) Golgi apparatus Lysosomes and vacuoles Peroxisomes Chloroplasts (only plants) Cytoskeleton Organelle Definitions Nucleus: stores genetic information nucleolus: where RNA is produced and where it joins with proteins to form the subunits of ribosomes nuclear envelope: double membrane separating the nucleus from the cytoplasm; has nuclear pores to let ribosomes out and proteins in Mitochondrion: powerhouse of the cell, carries out cellular respiration producing ATP molecules Endoplasmic Reticulum: Rough ER: studded with ribosomes, processes proteins Smooth ER: lacks ribosomes, synthesizes lipids Golgi Apparatus: processes, packages, and secretes modified cell products Lysosomes and Vesicles: lysosomes: vesicle that digest macromolecules and even cell parts,recycling station, arise from golgi vesicle: membranebounded sac that stores and transports substances Peroxisomes: vesicles with specialized enzymes for catalysis of peroxides Cytoskeleton: maintains cell shape and assists movement of cell parts The Plasma Membrane phospholipid bilayer with attached or embedded proteins; polar head and nonpolar tail fluidmosaic model: protein molecules form a shifting pattern within the fluid phospholipid bilayer fluid, dynamic OUTSIDE: carbohydrate chain: glycoproteins and glycolipids: help mark the cell, only on outside of cell phospholipid bilayer (hydrophilic heads) INSIDE/OUTSIDE: transmembranal protein: portion exposed to outside, portion exposed to inside INSIDE: peripheral protein: associated with cytoskeleton cholesterol: important for permeability (good in, bad out) Selective Permeability of Plasma Membrane What gets through most easily? Things that are small (water, gases) and have no charge Larger (fats, amino acids, etc) don't get through, they need a protein Things that are small but charged (charged molecules and ions): won't make it through, will be repelled, instead they go through ion channels: specialized for that particular ion aquaporin: proteins for water transport, water travels freely across the membrane through these Simple Diffusion Across the Membrane Diffusion: the random movement of molecules from an area of higher concentration to an area of lower concentration until they are equally distributed (until equilibrium is achieved) Passive: no energy is needed ex. food coloring dispersing in water, oxygen diffusion across membrane Osmosis Osmosis: the simple diffusion of water, the direction by which water will diffuse is determined by the tonicity of the solutions inside and outside the cell tonicity is based on solutes within a solution: the higher the concentration of solutes, the less water and vice versa. Typically water will diffuse from the area that has less solute (more water) to the area with more solute (less water) isotonic: same concentration of solutes and water on both sides of the membrane, cells maintain normal shape and size, ex. body fluids hypotonic: solutions that cause cells to swell/burst: more water outside (less solute), more solute inside (less water) so water moves inside the cell. lysis=bursting cells hypertonic: solutions that cause cells to shrink due to loss of water: more water inside cell (less solute), less water outside cell (more solute), water moves out of the cell *Drink sea water? No! Cells will shrink *Drink large volume of water? No! Cells will burst Facilitated Diffusion a molecule is transported by means ofprotein carriers from the side of higher concentration to the side of lower concentration passive: no energy used to move down (along) the concentration gradient highly specific Examples of facilitators: protein carriers, ion channels Examples of molecules: sugars (glucose), amino acids Active Transport a molecule is moving from a lower to a higher concentration > against the gradient uses energy! and requires a protein carrier (pump) ex. sodiumpotassium pump: sodium ions move to outside, potassium ions move to inside: associated with nerve and muscle cells, cystic fibrosis Transport of Large Stuff endocytosis: a portion of the plasma membrane invaginates (forms a pouch) to envelop a substance and fluid; going inside the cell examples of endocytosis: Phagocytosis: cellular eating: white blood cells are able to take up pathogens, large stuff enters this way Pinocytosis: cells take up small molecules and fluid (typical), smaller stuff entering Receptormediated endocytosis: molecules first bind to specific receptors and are then brought into the cell by endocytosis exocytosis: a vesicle fuses with the plasma membrane as secretion occurs (going out of the cell) ex. neurotransmitters leaving the cell The Nucleus Nucleus: stores genetic information nucleolus: where RNA is produced and where it joins with proteins to form the subunits of ribosomes nuclear envelope: double membrane separating the nucleus from the cytoplasm; has nuclear pores to let ribosomes out and proteins in Chromosomes: 46 total, 23 from mom 23 from dad The Endomembrane System (Endoplasmic Reticulum) Ribosomes: organelles composed of proteins and RNA, make proteins based on DNA in nucleus Often attached to rough ER but can also be found within the cytoplasm either singly or in groups called polyribosomes Rough ER: studded with ribosomes, closer to the nucleus, proteins are synthesized Smooth ER: does not have ribosomes, makes lipids and carbs, gets rid of toxins The ER forms transport vesicles in which large molecules are transported to other parts of the cell. Often these vesicles are on their way to the plasma membrane or golgi apparatus The Endomembrane System (Golgi Apparatus) Here, proteins and lipids received from the ER are modified and packaged into vesicles Peroxisomes peroxide is a biproduct of metabolism involved in amino acid metabolism Single membrane, vesicles with specialized enxymes inside for catalysis of peroxides(toxic, need to be degraded) Cytoskeleton Helps maintain a cell's shape and either anchors the organelles or assists in their movement, as appropriate SHAPE, MOBILITY Made of three different proteins: 1. Actin: makes proteins, helps in endocytosis, shape, closest to cell membrane 2. Keratin: maintenance of cell structure, stabilize 3. Tubulin: railroad transport within cell Microtubules: cylinder that contains a row of a protein called tubulin, maintain shape of cell, act as tracks (railroad) along which organelles move Actin filaments are long and involved in movement Mitochondria Energy convert chemical energy of glucose products into ATP uses oxygen and gives off carbon dioxide process of producing ATP= cellular respiration Endosymbiotic theory: they were originally prokaryotes engulfed by a cell (explains why they have a double membrane/2 membranes)...one is internal and highly invaginated (increases surface that contains proteins) and the other is external Cellular Respiration Breaks down glucose to carbon dioxide and water: yields high level of energy Three Pathways Involved: 1. Glycolysis 2. Citric Acid Cycle 3. Electron Transport Chain Glycolysis: means sugar splitting, a 6 carbon glucose is split into 2 three carbon molecules, occurs in cytoplasm and found in every type of cell Citric Acid Cycle: occurs in mitochondria, stripping electrons from glucose to produce carbon dioxide (oxygen in, CO2 out) Electron Transport Chain: synthesis of ATP The Metabolic Fate of Pizza Large complex molecules need to be degraded into simple units (proteins>amino acids, carbs>glucose, fats>glycerol/fatty acids) Small molecules can enter the cellular respiration process at different places LECTURE 6: TISSUES Four Basic Types of Tissues 1. Connective tissue: binds and supports body parts 2. Muscular tissue: move the body and its parts 3. Nervous tissue: receives sensory info. and conducts nerve impulses 4. Epithelial tissue: covers body surfaces and lines body cavities tissue specialized cells of the same type to perform a common function organ made of many tissues, all the different tissues together make an organ Connective Tissue Made of: cells, ground substance, protein fibers Most diverse! cells: adipose cell (stores fat), stem cell (divides to produce other types of cells), white blood cell (engulfs pathogens or produces antibodies) ground substance: noncellular material that separates the cells: fills spaces between cells and fibers (carbs, modified lipids) protein fibers: three possible types:collagen fibers unbranched strong and flexible, reticular fibers branched, thin and forms network, elastic fibers branched and stretchable, not as strong as collagen but more elastic 3 Types of Connective Tissue 1. Fibrous 2. Supportive 3. Fluid 1. Fibrous Connective Tissue Loose and Dense Loose: found underneath the skin, fibers create loose open framework, lungs, arteries, urinary bladder, forms a protective covering enclosing many internal organs like muscles, blood vessels and nerves, supports epithelium, protective covering membranes Dense: many collagen fibers densely packed together, tendons and ligaments, more specific function than loose, insulation & energy source 2. Supportive Connective Tissue Cartilage and Bone Cartilage: solid yet flexible matrix (ground substance and fibers), nose, ribs, ear, cushions in knee joint and between vertebrae in backbone Bone: solid and rigid matrix because of lots of cells in ground substance 3. Fluid Connective Tissue Blood and Lymph Blood: contained in blood vessels, plasma and formed elements, red (oxygen and carbon dioxide) and white blood cells, platelets for clotting Lymph: contained in lymphatic vessels Muscle Tissue Specialized to contract, movement Three Types: 1. Skeletal 2. Smooth 3. Cardiac 1. Skeletal Muscle Tissue Attached to bone by tendons: mobility, running, motion, occurs in muscles When it contracts, body parts move Voluntary control striated (striped) cells with multiple nuclei 2. Smooth Muscle Tissue no striations (no stripes), spindleshaped cells each with a single nucleus Involuntary control in walls of bladder, intestine/digestive tract, and blood vessels functions in movement of substances 3. Cardiac Muscle Tissue In the wall of the heart has branching, striated cells, each with a single nucleus functions in the pumping of blood involuntary cytoplasm between cells is interconnected Nervous Tissue Consists of nerve cells (neurons) and neuroglia (the cells that support and nourish the neurons) Sensory input, integration of data, motor output neuron: conduct electrical impulses Glial cells (neuroglia) are the majority: supporting cells, in brain Dimensions: 1. microglia: maintenance, remove debris, protection 2. astrocytes: brings nutrients to neuron, removal of waste 3. oligodendrocytes: in CNS (brain and spinal cord), important for fast processing, produce myelin> myelin insulates 4. schwann cells: in PNS (outside the brain) for same function as those above (produce myelin) Epithelial Tissue Consists of tightly packed cells that form a continuous layer Where? Skin Blood vessels (lining blood passages and lymph vessels) Intestine (lining digestive and excretory) Lining of the lungs (respiratory passages) Everywhere with surfaces What is their function? absorb nutrients protection secretion excretion filtration Epithelial Tissue Cell Shapes Squamous (flattened) Cuboidal (cube) Columnar (columns) Classes of Epithelial Cells Simple (one layer) Pseudostratified [columnar] (layered but all cells are not the same size) Stratified (multilayer) Combinations/Types Simple Squamous: lining of lungs, blood vessels, protects, (transport?) Simple Cuboidal: lining of kidney tubules, various glands, absorbs molecules Simple Columnar: lining of small intestine, oviducts, absorbs nutrients Pseudostratified Columnar: lining oftrachea, sweeps impurities toward throat Stratified Squamous: lining of nose, mouth, esophagus, anal canal, vagina(many layers), protects
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'