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Test one. Terminology. Anatomy Form of organism Ana = up, Tome = to cut Physiology Physis = nature, Logia = to study Function Iris – rainbow Autopsy Auto = self, opsis = to view. Homeostasis. Homeo = same, Stasis = Still Maintain a stable internal environment
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Terminology • Anatomy Form of organism • Ana = up, Tome = to cut • Physiology • Physis = nature, Logia = to study Function • Iris – rainbow • Autopsy • Auto = self, opsis = to view
Homeostasis • Homeo = same, Stasis = Still • Maintain a stable internal environment • e.g. Body temperature (98.6°), Heart rate (72beats/min), pH balance • Consumes most metabolic energy of all processes
Requirments for homeostasis • 1. Receptors – Provide information about environment • Thermoreceptors –detect temperature • 2. Control Center with Set point • Control Center = sets the range at which the value is maintained • Hypothalamus = Control Center • Set point = range of values • 98.6°F = set point • 3. Effectors • Muscles or glands • Responds to input from control center • Alters conditions • e.g. Sweat glands secrete sweat to cool body • Example of Homeostatic Mechanism
Examples • Example of Homeostatic Mechanism • Stimulus = hot environment → Body temperature increases → • Detected by thermoreceptors (receptors) → info into hypothalamus (control center) → Hypothalamus detects deviation from body temp (set point) → • output signal to sweat glands (effectors) → Sweat glands secrete sweat → • response = body temp cools → Stimulus decreases
Two types of feedback • Negative Feedback = response to decrease the deviation from a set point • Most homeostatic mechanisms rely on negative feedback • Positive Feedback = response to increase deviation from set point • Short lived and uncommon • e.g. Child birth
Characteristics of life • Organized system • 1 or more cells, humans have 50-100 Trillion cells • Reproduction • Consumes energy, usually ATP • Maintains homeostasis • Growth
Requirements to maintain life • Water (H2O) – Transportation & required for metabolic processes • Food – energy & building blocks • Oxygen – required to release energy from metabolic processes • Heat – energy, regulates metabolic reactions • Pressure – force, for breathing & circulation
Subatomic Particles Protons, Neutrons, Electrons • ↓ • Atom Hydrogen, Oxygen, Carbon • ↓ • Molecules H2O (water), C6H12O6 (Glucose) • ↓ • Macromolecules Proteins, Nucleic Acids, Polysaccharides • ↓ • Organelles Mitochondria, Golgi Apparatus • ↓ • Cell Neuron, Muscle Cell, Osteocyte • ↓ • Tissue Neural tissue, Epithelial Tissue, Bone tissue • ↓ • Organ Liver, Stomach, Brain • ↓ • Organ System Digestive, Skeletal, Cardiovascular • ↓ • Organism Human
Common terms • Common Terms • Biochemistry = chemistry of living things • Matter = Anything that has mass and takes up space • Solids, Liquids, Gas • Element = Fundamental substance of matter • Groups of atoms of 1 type, e.g. Carbon, Oxygen, Hydrogen • Compund = Combination of 2 or more atoms, e.g. H2O, C6H12O6 • Molecule = 2 or more atoms chemically bonded together • May either be an element or may be a compound
Bulk elements • Carbon (C) Oxygen (O) Hydrogen (H) • Nitrogen (N) Magnesium (Mg) Sulfur (S) • Sodium (Na) Potassium (K) Calcium (Ca) • Chlorine (Cl)
Trace elements <0.1% of elements, but have important functions • Cobalt (Co) Zinc (Zn) Copper (Cu) • Iron (Fe) Fluorine (F) Mangenese (Mn) • Iodine (I)
Atomic Structure • Nucleus • Protons • Neutrons • Electrons – Orbit nucleus
Subatomic Particle Atomic Weight (Daltons) Charge • Proton 1 +1 • Neutron 10 • Electron 0 -1 • For most atoms, number of protons = number of electrons, and therefore are neutral • Number of neutrons may vary
Atomic Number (AN) = Number of protons in an atom • Defines the identity of an atom • Changing the atomic number changes the atom • Atomic Weight (AW) = Number of protons + number of neutrons • Examples: • Hydrogen = 1proton, 1 electron, 0 neutrons • Atomic Number = 1, Atomic Weight = 1 • Helium = 2 protons, 2 electrons, 2 neutrons • Atomic Number = 2, Atomic Weight = 4 • Lithium = 3 Protons, 4 Neutrons, 3 Electrons • Atomic Number = 3, Atomic Weight = 7
Isotopes • Isotopes • Same atomic number, but different atomic mass • Number of neutrons may vary • Example: • Isotope 1: Isotope 2 • Oxygen (O) Oxygen (O) • 8 protons 8 protons • 8 electrons 8 electrons • 8 neutrons 9 neutrons • Atomic Number: 8 8 • Atomic Weight: 16 17
Molecular Formula • Shorthand of molecules • Water = H2O……2 Hydrogen + 1 Oxygen Molecule • Glucose = C6H12O6……6 Carbon + 12 Hydrogen + 6 Oxygen
BONDING atoms • Electron Orbit (Shell) • Electrons orbit the nucleus in discrete orbits • Inner orbit = holds 2 electrons • 2nd orbit = holds 8 electrons • 3rd orbit = holds 8 electrons • Octet Rule • Except for the 1st electron orbit, which holds 2 electrons, each additional orbit holds 8 electrons
ions • Ion = atom that gains or looses electrons • Cation – Positively charged ion • Anion – Negatively charged ion • Example: • Sodium (Na) = 11 protons, 12 neutrons, 11 electrons • 1 electron in outer orbit • Outer lone electron is easily lost • Na + = cation • Chlorine (Cl) = 17 protons, 18 neutrons, 17 electrons • 7 electrons in outer orbit, which can hold 8 electrons • 1 electron is easily gained • Cl- = anion
Bonds cont. • Ionic Bond • Oppositely charged ions attract and form a bond • Ionic bonds form arrays such as crystals, but do not form molecules • Covalent Bond • Atoms share electrons • Hydrogen forms single bonds, H-H • Carbon forms four bonds, Oxygen forms 2 bonds, O=C=O
Covalent bonds • NonPolar Covalent Bond • Equal sharing of electrons, e.g. H2 (H-H) • Polar Covalent Bond • Unequal sharing of electrons, e.g. H2O (H-O-H) • Oxygen has stronger attraction to electrons & is slightly – charged • Hydrogen partially gives electrons to Oxygen & is + charged
Hydrogen bond • Attraction of + hydrogen end to – Oxygen end • Weak bonds at body temperature • Forms crystals at lower temperatures, e.g. ice
Chemical reactions • 1. Synthesis • A + B → AB • 2. Decomposition • AB → A + B • 3. Exchange • AB + CD → AD + BC • 4. Reversible • A + B ↔ AB
Electrolytes • Electrolytes = release ions in water • e.g. NaCl → Na⁺ + Cl⁻ (ions dissociate in water) • 2. Acids – electrolytes that release H⁺ (protons) in water • e.g. HCl → H⁺ + Cl⁻ • 3. Base – electrolytes that release OH⁻(hydroxide ions) in water • e.g. NaOH → Na⁺ + OH⁻ • 4. Acid + Base → Salt + Water • e.g. HCl + NaOH → NaCl + H2O
pH • Neutral, pH = 7.0 • number of protons = number of hydroxide ions (H⁺ = OH⁻) • e.g. Water H2O → H⁺ + OH⁻ • Acids, pH < 7.0 • Number of protons is greater than number of hydroxides (H⁺ > OH⁻) • Bases, pH> 7.0 • Number of protons is less than number of hydroxides (H⁺ < OH⁻)
PH • average pH is 7.35-7.45 • Acidosis = pH < 7.3 • Alkalosis = pH > 7.5 • Buffers = chemicals that resist changes in pH, stabilizes blood plasma pH levels
inorganic • Water (H2O) • 2/3 of weight in person • Most metabolic reactions occur in water • Transports gasses, nutrients, wastes, heat • Oxygen (O2) • Used to release energy from nutrients • Carbon Dioxide (CO2) • waste byproduct of metabolic reactions in animals • Inorganic Salts • Na⁺, Cl⁻, K⁺, Ca2⁺, HCO3⁻ (bicarbonate), PO42⁻ (Phosphate), ect. • Role in metabolism, pH, bone development, muscle contractions, clot formation
Cells • Basic unit of life • 50-100 Trillion cells in human body • Size and shape vary • Size • measured in micrometers (µm) • 1 µm = 1/1000mm • Red Blood Cell = 7.5 µm • Varieties • 260 types of cells in body, all from 1 fertilized egg • Differentiation = forming specialized cells from unspecialized cells • Cells include neurons, skeletal muscle, osteocytes (bones), red blood cells, ect.
Cell membrane • Maintains integrity of cell • Fluid membrane • Flexible & elastic • Selectively Permeable • Allows only selective substances into and out of cell • Permits communication between cell and environment • Signal Transduction = cell interprets incoming messages
Structure • Bilayer of phospholipids • Phosphate “Head” • Polar group • Hydrophilic “water loving” = water soluble • Fatty Acid Chains “tail” • Nonpolar groups • Hydrophobic “water fearing” = insoluble in water • Oily • Cholesterol • Membrane Proteins
Formation of membrane • Phospholipids align in water • Expose polar heads to water = polar outside • Hide nonpolar tails from water = oily inside • Nonpolar interior • Allows nonpolar molecules to cross into and out of cell • e.g. O2,CO2, steroid hormones • Polar molecules cannot cross cell membrane • e.g. H2O, sugars, amino acids • Cholesterol • Rigid steroid rings that add support to cell membrane • Membrane Proteins = Many types embedded in cell membrane
Membrane proteins • Integral Proteins • Spans across membrane • Forms channels and pores • e.g. aquaporins, Na+ channels • Peripheral Proteins • Project from outer surface • May be glycoprotein (protein + sugar) • Does not penetrate hydrophobic portion of membrane • Usually attach to integral proteins • Transmembrane Protein • Spans from outside cell to inside cell • Example 1 : Cellular Adhesion Molecules (CAM) • CAMs bind cells to other cells, or to proteins • May anchor cell, or communicate with other cells • Example 2: Many receptors • Transmits signals from extracellular environment into cell
nucleus • Nuclear Envelope • Double layered membrane • Nuclear Pores • Channel proteins that allow specific molecules into and out of nucleus • Messenger RNA leaves nucleus through pores • Ribosomes leave nucleus through pores • Nucleolus “little nucleus” • Dense body of RNA & Proteins • Produces ribosomes • Chromatin “colored substance” • DNA wrapped around proteins, called histones • Tightly coil and condense during mitosis to form chromosomes “colored body”
movements • Passive = requires no energy from cell • Active = requires energy from cell in form of ATP • Passive Movements • Diffusion • Random movement of molecules from higher to lower concentration • Molecules tend to diffuse = become evenly distributed • Requirements: • Cell membrane must be permeable to substance (small & nonpolar) • e.g. CO2, O2, Steroids • A concentration gradient must exist across membrane • One side of cell membrane must have a greater concentration than the other • Facilitated Diffusion • Diffusion with the aid of a carrier protein • Allows selective molecules to cross membrane • e.g. ions, sugars, proteins, amino acids • Carrier protein changes conformation • Substances move down concentration gradient • Limited by number of carrier protein
Osmosis • Diffusion of water across selectively permeable membrane • Water passes through channels, called aquaporins • Large solutes (salts) cannot cross membrane • Water follows salts • Osmotic pressure exerted on cell • Isotonic = same solute concentration inside and outside cell • Hypertonic = Greater solute concentration outside cell than inside cell • Water leaves cell & cell shrinks • Hypotonic = Greater solute concentration inside cell than outside • Water enters cell and cell swells • Cell may lyse “burst” • Filtration • Fluid is pushed across a membrane that larger molecules cannot cross • Separates solids from liquids • Force = hydrostatic pressure – derived from blood pressure
Active Transport • Movement against a concentration gradient • Requires ATP for energy (up to 40% of cell’s ATP) • Includes carrier proteins • e.g. Na+/K+ pumps can pump sodium out of cell and potassium into cell • Establishes a concentration gradient
Endocytosis • Cell membrane surrounds and engulfs particle • Types include • Pinocytosis • Cell takes up a fluid • Phagocytosis • Cell takes up a solid • Example: white blood cell engulfing a bacteria • Receptor mediated endocytosis • Selective endocytosis • Receptors on cell membrane bind to substance and trigger endocytosis • Provides specificity • Removes substances in low concentrations
Exocytosis • Reverse of endocytosis • Transport substances out of cell • Vesicle merges with cell membrane and releases content • Example- neuron releasing neurotransmitters
Transcytosis • Endocytosis & Exocytosis • Allows passage through a cell • e.g. HIV enters body by transcytosis through epithelium of anus, mouth, or reproductive tract.
Cell Cycle • Interphase • Mitosis • Cytokinesis = division of cytoplasm • Differentiation
Interphase • G1 (Gap) Phase • Cell is active and grows • Growth followed by a checkpoint that determines cell’s fate. • Cell May: • Continue to grow, then divide • Remain active, but not divide • Die • S phase (S = synthesis) • DNA replicates • G2 phase • Cell prepares for cell division