Biology 101 Week 4
Biology 101 Week 4 BY 101
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This 10 page Class Notes was uploaded by Alexandria Thomas on Monday September 19, 2016. The Class Notes belongs to BY 101 at University of Alabama at Birmingham taught by Mickie L Powell in Fall 2016. Since its upload, it has received 5 views.
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What is Karma?
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Date Created: 09/19/16
Introduction ● What is science? ● What is “science fiction”? ● What is “bad science”? ● What is “ pseudoscience”? Review from Chapter 1 Science is….. ● A body of knowledge ● E.g., biology, the study of living organisms ● The discovery of something new and unknown Characteristics ● Common set of biological molecules ● Compound of cells ● Growth ● Movement ● Reproduction ● Response to external environmental stimuli ● Metabolism ● Maintain homeostasis Do non living things have any of those characteristics? What about ● Fire? ● Clouds? ● Rocks? ● zombies? Living Humans Zombies ● Grow ● Do not grow from child to ● Move adult ● Reproduce and pass ● Can move; hindered by genetic information to offspring injuries ● Respond to external stimuli ● Metabolize ● Do not produce offspring; ● Maintain homostasis do not pass genetic information Elements: fundamental forms of matter ● H of protons defines elements Atoms: the smallest units of an element ● Atomic nucleus ● Protons: positive Ions: atoms with an electrical charge. ● Differences in number of protons and electrons Molecules: two or more atoms held together by chemical bonds ● Water molecules ● H2O ● 2 hydrogen atoms and 1 oxygen atom Water: a polar structure ● Different areas have different charges ● Oxygen: more electronegative ● Hydrogen: less electronegative (more positive) ● Dissolves salts ● Dissolves other polar molecules ● Hydrophilic: Waterloving ● e.g., alcohol ● Will not dissolve nonpolar molecules ● Hydrophobic: waterfearing ● e.g., cooking oil Water: allows contacts between solutes for chemical reaction ● Chemical reactions: changes in chemical composition of substance ● Reactants: solutes that are changes ● Product: Cohesion ● Tendency of molecules to stick together Moderating temperature ● Water absorbs heat energy ● Hydrogen bonds are disrupted first ● Additional heat will raise the water temperature Organic Chemistry ● Chemistry of biological systems ● Related to carboncontaining molecules ● Interaction with other elements ● E.g., hydrogen Carbon ● Chemical Tinkertoy connector ● Able to form four bonds ● Up to four different elements ● Combinations of single and double bonds Bermuda Triangle ● Pseudoscience “experience” ● Methane gas ● Bubbles engulf ships ● Ignited by lightning to crash planes Chemical Bonds ● Depend on the atom’s electron configuration ● Electron shells: energy levels ● Depends on distance from nucleus ● First shell holds up to 2 electrons ● Second and third shells holds up to 8 electrons each ● Valence shells: outermost shells ● If full, atom will not form bonds ● If not full, atom will form chemical bonds Types of Chemical bonds Covalent bonds ● Shared electrons ● Single bond: one pair of electrons ● Double bond: two pair of electrons Ionic Bonds ● Electrons transferred between atoms The pH scale ● Relative amounts of hydrogen ions (H+) and hydroxide ions (OH) ● Acid: more H+ and less OH ● pH lower than 7 ● Base: more OH and less H+ Macromolecules ● Large organic molecules ● Found in living organisms: ● Carbohydrates ● Proteins Carbohydrates ● Molecules of carbon, oxygen, and hydrogen ● Major source of energy for cells ● Made of sugar subunits Proteins ● Made of carbon, oxygen, hydrogen, and nitrogen ● Aminos acid subunits ● 20 different aminos acids ● Joined by peptide bonds ● Different amino acid combinations=different Lipids ● Composed mostly of carbon and hydrogen ● Hydrophobic molecules Three types of lipids: ● Fats: glycerol and three fatty acid tails ● Store energy ● Steroids: four fused carbon rings ● Cholesterol and sex Nucleic Acids ● Made of nucleotide monomer subunits ● Nucleotide: sugar + phosphate + nitrogenous base Types of nucleic acids ● RNA: For protein synthesis ● Ribose sugar ● DNA: Stores genetics information ● Deoxyribose sugar ● Double helix structure Complementary base pairing rules ● Four different nitrogen bases Diets, macromolecules, and behavior ● Do certain foods affect your behavior? ● Hyperactivity from sugar? ● Drowsiness from turkey? ● Scientific evidence does NOT support these food myths Prokaryotic and Eukaryotic cells ● All living things are made of cells. ● Contain similar macromolecules and cells structures Cell Theory Cell is the smallest unit of life All living things are made of cells Cells arise from preexisting cells Prokaryotic Eukaryotic Small; microscopic Larger; singlecelled or multicellular Simple Complex Genetic material Genetic material in nucleus No organelles Membrane Cell Walls No Cell walls The Tree of Life ● Common ancestor ● Led to 10 million organism of today ● Diversity due to natural selection Introduction ● How helpful are nutritional supplement? ● Americans spend $6 billion per year ● Twothirds of the American population take at least one supplement ● Do these supplement improve health and athletic performance? Water ● Disperses nutrients ● Dissolves and eliminates waste products ● Three liters lost each day in sweat, urine, feces ● 1.5 L replaced by food ● 1.5 L needed from other sources ● Decreased water intake Dehydration Minor Symptoms ● Muscles Cramps ● Fatigue ● Headaches ● Dizziness ● Nausea ● Confusion Severe Symptoms ● Hallucinations ● Heat Stroke ● May result in death Use of bottles Advantages ● Convenient ● Portable Disadvantages ● Bottles made from oil (1.5 million barrels) ● 86% of bottles go to landfills Sports Drinks ● High in simple sugars and calories ● Solute concentration higher than blood ● May lead to dehydration Carbohydrates: Main energy source ● Simple sugars (e.g, glucose) ● Enter body system quickly ● Complex carbohydrates (branching chains of simple sugars) ● Digested more slowly ● Starch: complex carbohydrate from plants ● Glycogen: complex carbohydrate from animals Processed Food ● Extensive refinement ● Stripped of nutritional value ● Whole Foods Fiber: Indigestible complex carbohydrates ● Essential for large intestine function ● Lowers cholesterol and reduces cancer risk Proteins ● Polymers of aminos acids ● Essential aminos acids: cannot be made in the body; must be obtained from food ● Complete proteins: contain all essential amino acids ● Proteins powder supplements ● Used to rebuild muscle after workouts ● Excess protein may not lead to extra muscle ● Stored body fat ● Health problems ● Bone loss ● Kidney damages Fats ● Energy storage molecules ● Acts as a cushion and insulator ● Consist of a glycerol attached to fatty acid tails ● Essential fatty acids: cannot be made in the body (e.g. omega3 and omega6) Saturated Fats Unsaturated Fats ● Fatty acids carbons bound to ● Fewer hydrogens bound to as much hydrogen as possible carbons ● Lack double bonds ● Contains double bonds ● Solid at room temperature ● Kinks in the tails ● Most animal fats are saturated ● Liquid at room temperature ● Most plant fat (oils) are unsaturated or polyunsaturated ● Hydrogenation ● Process of adding hydrogen atoms to unsaturated fat to make it a solid ● Trans Fats ● Produced by incomplete hydrogenation ● Double bonds are flat and not kinked ● May be linked to increased health risks ● Clogged arteries ● Heart disease ● Diabetes Micronutrients: required in small quantities ● Vitamins ● Minerals ● Not broken down by the body ● Not burned for energy Vitamins: organic substances ● Usually function as coenzymes ● Help to speed up body’s chemical reactions ● Only vitamin D can be synthesized in the body ● Other vitamins are supplied by foods Watersoluble vitamins Fatsoluble vitamins ● B and C ● A, D, E, and K ● Not stored by the body ● May be stored in Fats ● Leached out by boiling ● Excess accumulation can be ● Fresh vegetables are a better toxic source ● Certain cancers ● Heart disease ● Death Minerals: inorganic substances ● Do not contain carbon ● Water soluble ● Supplied through diet ● Essential for cell and body functions ● Fluid balance ● Muscle contraction ● Conduction of nerve impulses ● Building bones and teeth Calcium ● Commonly supplemented mineral for ● Blood clotting ● Muscle contraction ● Nerve impulses ● Healthy bone structure Antioxidants ● Most beneficial in whole foods ● Prevent cells from damage by free radicals ● Free radicals can damage DNA, arterial linings, and cell membranes Cytoplasms: includes cytosol and organelles ● Organelles: perform specific jobs required by the cell and work with other organelles ● Cytosol: watery matrix with salts and enzymes; houses the organelles Plasma membrane ● Encloses all cells ● Defines outer boundary of cells ● Isolates cell contents from environment ● Determines materials to be allowed in or out ● Semipermeable: some molecules can cross and some can’t Membrane Structure ● Phospholipid bilayer ● Hydrophilic heads maximize exposure to water ● Hydrophobic tails orient inside the membrane, away from water ● Fluid mosaic: lipids and proteins can move about within the membrane Subcellular structures ● Cell wall: helps protects certain cells (plants, fungi, bacteria) and maintains shape ● Nucleus: holds chromatin (DNA and proteins) in eukaryotic cells ● Nucleolus: synthesizes ribosomes; inside nucleus ● Mitochondrion: produces energy for the cell through cellular respiration ● Chloroplast: produces sugars through photosynthesis in plant cells ● Lysosome: contains digestive enzymes to recycle molecules ● Centrioles: move chromosomes during animal cell division ● Cytoskeletal elements: form cytoskeleton for maintaining shape and structural support ● Central vacuole: stores water, starch, and pigments in plant cells Supplements and cell structures ● Chlorophyll supplements ● Marketed for energizing, detoxifying, and healing wounds ● No evidence supports the marketing claims ● Human cells do not contain any chlorophyll ● Creatine ● Supposed to increase muscle or provide more powerful bursts of energy in athletes ● Effects of supplementing not well studied ● Kidney failure may be side effect of excess Membrane transport ● Plasma membrane: phospholipid bilayer is differentially permeable ● Hydrophobic substances pass more easily through the hydrophobic interior Equilibrium ● Concentrations of substances are equal on both sides of the membrane Passive transport: movement of molecules without energy ● Diffusion ● Facilitated diffusion ● Osmosis ● Diffusion: passive transport from area of high concentration to low concentration ● Very small, hydrophobic molecules ● Facilitated diffusion: transport proteins help move hydrophilic and charged molecules across the membrane ● From high to low concentration ● Without using energy ● Osmosis: diffusion of water across a membrane from high to low concentration Active transport ● Uses proteins to move molecules from low to high concentration ● Powered by energy from ATP ● Exocytosis: a membranebound vesicle fuses with the membrane and expels the large molecule outside the cell ● Endocytosis: a vesicle pinches the plasma membrane inward and brings a large molecule into the cell