Unit 1: Lesson 2 Chemical & Cellular Levels of Organization

Unit 1: Lesson 2 Chemical & Cellular Levels of Organization chemical and cellular levels of organization Supplemental Info Review: membrane transport organelle review protein synthesis (there is also a review on goodnotes) * DIAGRAM OF CELL TO LABEL: cell diagram learning activity organelle review based on supplemental review * •Atoms & Atomic Structure 2-1 in textbook - Elements are pure substances composed of only one type of atom -What are the most common body elements?: H, C, O, N (make up 96% of body elements) Atoms •Smallest unit of matter •What is an atom made up of?: - Neutrons (neutral/uncharged) - Protons (positive charge) - Electrons (negative charge) Why is an atom electrically neutral? •# of electrons = # of protons (making atoms electrically “neutral”) •Atoms are distinguished by their atomic number Know elements vs isotopes Is an Isotope stable/unstable? Unstable - they are not balanced and are potentially radioactive Electrons & Energy Levels: Electron Shells (there are 3 layers but we only care about the outermost shell) What is the outermost shell of an electron called? Valence shell Atoms with unfilled valence shells are unstable (or reactive) and will readily react with other atoms. = requiring balance •The instability of these atoms promotes interactions to form chemical bonds with other atoms Chemical Bonds •Atoms will give up, accept, or share electrons with other atoms in order to fill their valence shell (What’s the difference between a molecule and a compound?) A molecule (also only one element) is a group of two or more atoms held together by covalent bonds, a compound is 2 or more different elements which are chemically fixated. All compounds are molecules but not all molecules are compounds. Chemical Bonds (types of chemical bonds) What is a Ionic Bond? •One or more valence electrons from an atom are transferred to another atom •Ion→ an atom that has a positive charge (cation) or negative charge (anion) - Atoms become ions through ionization •Ionization → the process of gaining or losing electrons •Chemical bonds created by the electrical attraction between anions and cations What is a covalent bond? •Strong bonds •Created when atoms share electrons with each other (in valence shell) •What is Non-polar covalent bonds Everything is equal •What is Polar covalent bonds Unequal sharing of electrons (positive and negative end) (What are free radicals?) An atom or ion or molecule with unpaired electrons in valence shell making it highly reactive What is a Hydrogen Bond? •Weak polar bonds between adjacent molecules based on electrical attractions •Slight positive charge on hydrogen atom is attracted to the slight negative charge on another atom (oxygen, nitrogen, fluorine) •Hydrogen bonds are not strong enough to create molecules, but can pull molecules closer together - Example: Surface tension on a glass of water (surface tension also affects membranes in our body) The Importance of Water •Why is it so important? - Universal solvent - Reactivity- active component in hydrolysis and dehydration synthesis - High heat capacity (temperature regulation) - lubricant Solubility - Substances may be hydrophilic or hydrophobic •What is Hydrophilic- interact readily with water; water soluble; polar covalent bonds (eg: glucose, amino acids) •What is Hydrophobic- do not readily interact with water; insoluble in water; non-polar covalent bonds (eg: hydrocarbon chain of fat molecules) (What are electrolytes?) Soluble inorganic substances which will conduct a current (charged) in water Electrolytes Important ones are sodium chloride, potassium chloride, and sodium bicarbonate •Importance of fluid and electrolyte balance - Changes in electrolyte concentrations in the body can have a significant impact on vital functions. Different electrolytes affect different organs and they must be balanced •The kidneys, digestive tract, and skeletal system play important roles in regulating fluid and electrolyte levels Acids & Bases •What is an Acid? are electrolytes that release hydrogen ions in water (has -ic acid) •What is a Base? are electrolytes that release ions that bond with hydrogen ions (has -oxide) What is pH •pH is a measure of the concentration of hydrogen ions - The pH of a solution indicates its level of acidity (or alkalinity) - pH scale 0-14 What is considered neutral pH? Acidic? Basic? - pH of 7 considered neutral - pH < 7 is acidic - pH > 7 is basic (alkaline) What is the pH of blood? •pH of blood: 7.35-7.45 pH: What are the consequences of abnormal fluctuations in pH? •Acidosis- blood pH < 7.35 •Alkalosis- blood pH >7.45 •Chemicals that resist pH changes? are called buffers (body has these to maintain balance) know of calcium carbonate What is a Macromolecule? Living organisms make these particular molecules which contain carbon atoms. •What are the 4 basic types of macromolecules? 1.Carbohydrates 2.Lipids 3.Proteins 4.Nucleic acids •Macromolecules are made up of _______? Monomers (or building blocks ex: amino acids for proteins) •What is Dehydration synthesis? Monomers join to make polymer What is Hydrolysis? Polymers break down into monomers What is the purpose of Carbohydrates? •Act as an energy source for the body What are the types of carbohydrates? Which one can we use? Monosaccharides (we can actually use because it is a simple sugar), Disaccharides, Polysaccharides (need to be broken down to be used) What is an example of a monosaccharide? Polysaccharide? Glucose and for polysaccharides - cellulose, starches, glycogen What is a lipid? What are some examples? •Not soluble in water •Important role in energy storage, communication, insulation, and protection - Glycerides - Steroids What is a protein? •Made up of amino acids joined together by peptide bonds. •Important proteins: hemoglobin, collagen, keratin, antibodies and enzymes A Closer Look at Enzymes - refer to pg 56 fig 2-23 What are enzymes? •Enzymes are proteins required for cellular metabolism has the suffix (-ase) •Responsible for catalyzing (speeding up chemical reactions) necessary for sustaining life •What are Basic characteristics of all enzymes? Specificity Saturation Limits Regulation What are Nucleic Acids made up of and what do they do? •Made up of nucleotides, responsible for genetic information What is a nucleotide made up of? - Each nucleotide contains a pentose (5-carbon sugar), a phosphate group, and a nitrogenous base What are the nitrogenous bases? - 5 nitrogenous bases: adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U) •2 classes of nucleic acid:(refer to pg 59 table 2-6) - Deoxyribonucleic acid (DNA) - Ribonucleic acid (RNA) ATP & Cellular Energy ● What is Phosphorylation - Attaching a phosphate group to another molecule ● Energy storage → ADP is converted to ATP ● Energy release → ATP is converted to ADP ATP Generation: Aerobic vs Anaerobic Processes What is Anaerobic? •Does not require oxygen •Glycolysis •What is the net gain of ATP? (2) What is Aerobic? •Requires oxygen •Kreb’s Cycle (citric acid cycle) •Electron Transport Chain •What is the net gain of ATP? (34) Cellular Levels of Organization 2 general classes of cells: 1.Sex cells (germ cells or reproductive cells) •Male sperm •Female oocytes (cells that develop into ova) 2 .Somatic cells•All body cells other than sex cells Cell Structure •Plasma membrane = cell membrane •Nucleus = genetic material of cell •Cytoplasm = everything between the membrane and the nucleus - cytosol = intracellular fluid - organelles = subcellular structures with specific functions Plasma Membrane Functions: •Physical isolation •Regulation of exchange with the environment •Sensitivity to the environment •Structural Support Structure & Composition: •Phospholipid bilayer - What is the role of cholesterol? •Membrane Proteins •Membrane Carbohydrates Membrane Proteins Two classes of proteins: 1.Integral proteins (transmembrane proteins) •Within the membrane 2.Peripheral proteins •Bound to inner or outer surface of the membrane Types of membrane proteins: 1.Anchoring proteins 2.Recognition proteins 3.Enzymes 4.Receptor proteins 5.Carrier proteins 6.Channels Membrane Carbohydrates Proteoglycans, glycoproteins, and glycolipids •Extend outside cell membrane •Form sticky “sugar coat” (glycocalyx) Functions of the glycocalyx •Lubrication and protection •Anchoring and locomotion •Specificity in binding (function as receptors) •Recognition (immune response) Homework (supplemental docs on eclass) 1.Review the function of the organelles within the cytoplasm: •Cytosol •Cytoskeleton •Endoplasmic reticulum •Golgi apparatus •Lysosomes •Peroxisomes •Mitochondria •Nucleus •See Figure 3-1 in your text 2. Review the steps of protein synthesis Refer to notes, for functions of organelles, there is flashcards, look in textbook and supplemental review for protein synthesis Movement across the plasma membrane •Plasma membranes exhibit selective permeability •Membrane transport may involve passive or active processes •Active processes require energy (ATP) •Passive Processes: - Diffusion - Osmosis - Facilitated Diffusion •Active Processes: - Active Transport - Endocytosis - Exocytosis Diffusion •Passive diffusion of substances (molecules/ions) across the membrane along a concentration gradient •Net diffusion •Molecules are in continuous random motion and tend to become more evenly distributed over time •Example: Movement of O2 and CO2 (What factors influence the rate of diffusion?) Simple & Channel-Mediated Diffusion Filtration •Transport of water and molecules through the plasma membrane, by the force of hydrostatic pressure (HP) – pressure exerted by standing fluid on an object •Examples in blood capillaries, glomerulus (in kidneys) Osmosis •Refers to the diffusion of water across a selectively permeable membrane •Water will flow toward the solution with a higher concentration of solutes (and lower concentration of water) •Terms to Know: - Osmotic pressure - Hydrostatic Pressure - Aquaporins - Osmolarity/Osmotic Concentration - Tonicity What is “tonicity”? •The concentration of non-penetrating solutes in the solution surrounding the cell (ECF) •The effect that the solution has on cell volume and shape •Isotonic •Hypotonic •Hypertonic Effects of Tonicity on Cells Assisted Membrane Transport •Large, poorly lipid-soluble molecules cannot cross the plasma membrane on their own. •Cell must provide mechanisms for transporting these molecules in and out of cell •Two different mechanisms: - Carrier-mediated transport - Vesicular transport Carrier-Mediated Transport •Carrier proteins span the plasma membrane •They can reverse shape so binding sites on either side of membrane can be exposed •Two forms: - Passive (facilitated diffusion) - active (active transport) •Three important characteristics: - Specificity - Saturation - Regulation Active Transport •Energy is needed to move ions or molecules across the membrane •Is not dependent on the concentration gradient •Primary active transport - Sodium-Potassium Exchange Pump •Secondary active transport Vesicular Transport •Uses small membranous sacs (vesicles) at the plasma membrane •Allows for the movement of larger particles •This requires energy expenditure by the cell •Two forms of vesicular transport: - Endocytosis – into the cell - Exocytosis – out of the cell Why does membrane transport matter? Clinical Application: - Cystic Fibrosis Cell Life Cycle cell life cycle External Resources: - phosphorylation video - protein synthesis - cell anatomy - cell membrane transport Readings: - Chapter 2 (pp. 27-60) - Chapter 3 (pp. 66-109) Mastering AP: - Dynamic study modules - Practice questions (go to chapter, practice tests) - Questions in the textbook Can also draw Look at registerednursern questions cell structure and function