Laboratory Safety Skills It is YOUR responsibility to protect yourself and other students by conducting yourself in a safe manner while in the laboratory. It is also your responsibility to read the Flinn safety contract, sign it, and have it signed by a parent or guardian. You will NOT be allowed to participate in labs until you return your signed safety contract AND pass the laboratory safety quiz.
General Guidelines of Laboratory Safety Only perform experiments specifically assigned by your teacher. Familiarize yourself with the investigation and all safety precautions before entering the lab. Before beginning work, tie back hair, roll up loose sleeves, and put on any required personal protective equipment. Always wear a lab apron and safety goggles. No contact lenses allowed in the lab. Know the location of all safety and emergency equipment used in the laboratory. Immediately report any accident, incident, or hazardno matter how trivialto your teacher. In case of fire, alert your teacher and leave the lab! Do not have or consume food or drink in the lab. Do not fool around in the lab. Do not apply cosmetics in the lab. Keep your work area neat and uncluttered. Clean your work area at the conclusion of each lab period as directed by your teacher. Wash your hands with soap and hot water after each lab period. Pg. 1024
Stages of Scientific Investigations Collecting Observations Observation is the basis of scientific research. Observation is the act of noting or perceiving objects or events using the senses. Asking Questions Forming Hypotheses and Making Predictions Hypothesis: an explanation that might be truea statement that can be tested by additional observations or experimentation. Prediction: the expected outcome of a test, assuming the hypothesis is correct. Viewing Conclusions in Context
Stages of Scientific Investigations Confirming Predictions Experiment: a planned procedure to test a hypothesis. Control group: a group in an experiment that receives not experimental treatment. Independent Variable: the factor that is changed in an experiment. Dependent Variable: the factor that is measured in an experiment. Drawing Conclusions Viewing Conclusions in Context
Scientific Explanations Scientists build theories from questions, predictions, hypotheses, and the findings of their experiments. When related hypotheses consistently explain scientific events, a theory is formed. Theory: a set of related hypotheses that have been tested and confirmed many times by many scientists. Unites and explains a broad range of observations.
Chemistry of Life: Nature of Matter, Water and Solutions Ch. 2.1, 2.2
Atoms Chemistry will help you learn about biology because organisms are chemical machines! Atom: smallest unit of matter that cannot be broken down by chemical means. Made of: Protons: positive, in nucleus Neutrons: neutral, in nucleus Electrons: negative, in electron cloud
Elements and Chemical Bonding Atoms can join with other atoms to form stable substances. The force that joins atoms is a chemical bond. Element: a pure substance made of only one type of atom Differ in the number of protons in the nucleus Compound: a substance made of the joined atoms of two or more different elements in known proportions Represented by chemical formulas
Covalent Bonds Covalent Bonds: form when two or more atoms share electrons to form a molecule Molecule: A group of atoms held together by covalent bonds
Ionic Bonds Sometimes atoms or molecules gain or lose electrons. Ion: An atom/molecule that has gained or lost an electron Ionic Bonds: a bond formed when ions of opposite charges are attracted Found in table salt (Sodium Chloride, NaCl)
Hydrogen Bonds Hydrogen Bonds: Bonds based on polarity of molecules which causes chemical attraction. Bonds with an unequal distribution of electrical charge are called polar molecules. Water molecules are polar and often form hydrogen bonds. The different charges in each molecule makes the molecules attract each other.
Water in Living Things, Storage of Energy 70% of your body is made up of water Water absorbs heat slowly Water retains energy well Water absorbs heat more slowly and retains this energy longer than other substances, helping us maintain our body temperature. Controlling body temperature is important part of homeostasis. Homeostasis: the maintenance of a constant internal state in a changing environment.
Cohesion and Adhesion Cohesion: an attraction between substances of the same kind. Molecules of water are stuck together because of the hydrogen bonds between water molecules. This is why water forms drops! Adhesion: an attraction between different substances. Water is attracted to other polar substances. Capillary action is the process in which water molecules move upward through a narrow tube because the water sticks to the wall of the tube.
Polarity The polarity of water enables many substances to dissolve in water. Solution: a mixture in which one or more substances are evenly distributed in another substance. Non-polar substances such as oil do not dissolve well. Ionic compounds and polar molecules dissolve best in water, because they are charged like the water. When ionic compounds are dissolved in water, the ions become surrounded by polar water molecules.
Acids and Bases While the bonds in water molecules are strong, sometimes these bonds break, forming a hydrogen ion (H + ) and a hydroxide ion (OH - ). H 2 O H + + OH - Acids: compounds that form hydrogen ions when dissolved in water and have a pH below 7 Bases: compounds that reduce the concentration of hydrogen ions in a solution and have a pH above 7 pH: a value used to express the acidity or alkalinity of a solution, this is the pH scale:
Chemistry of Life: Chemistry of Cells Ch. 2.3
Organic Compounds Most non-water matter in your body is made of organic compounds Organic compounds contain carbon atoms that are covalently bonded to other elements such as H (Hydrogen), O (Oxygen) and other C (Carbon) atoms Biomolecules: organic compounds that are important in the structure and function of living organisms. There are 4 biomolecules you need to know for this class: Carbohydrates, Lipids, Proteins, and Nucleic Acids
Dehydration Synthesis and Hydrolysis Dehydration Synthesis: A chemical reaction that builds up molecules by losing water molecules. Hydrolysis: The process of splitting a compound into fragments with the addition of water; a kind of reaction that is used to break down polymers into simpler units, e.g. starch into glucose. So, Dehydration Synthesis LOSES water, while Hydrolysis ADDS water! Which process is represented by the image below?:
Carbohydrates Organic compounds made of carbon, hydrogen and oxygen atoms in the proportion of 1:2:1 Carbohydrates are basically made of carbon and water! Carbohydrates are built from single sugars called monosaccharides Polysaccharides are chains or three or more monosaccharides. Polysaccharides are macromolecules
Lipids Lipids are nonpolar molecules that are not soluble or are mostly insoluble in water Made of fatty acids attached to a glycerol Include fats, phospholipids, steroids, and waxes. Important in cell membranes Fats store energy
Proteins A large molecule formed by linked smaller molecules called amino acids Amino acids contain Nitrogen, an important element for life! Amino acids are the building blocks of proteins. 20 different amino acids are found in proteins Some proteins are enzymes and promote chemical reactions
Nucleic Acids All of your cells contain nucleic acids DNA and RNA are two common nucleic acids Nucleic acids are long chains of smaller molecules called nucleotides A nucleotide as three parts: a sugar, a base, and a phosphate group
Energy and Chemical Reactions Ch. 2.4
ATP ATP Stands for Adenosine triphosphate A single nucleotide with two extra energy storing phosphate groups (so why is it called A T P?) Cells need a steady supply of ATP to function http://biochemisms.com/tag/atp/
Energy for Life Processes Energy is the ability to move or change matter. Exists in many forms: light, heat, chemical, mechanical, electrical; can be converted to other forms. Energy can be stored or released by chemical reactions. Chemical reactions are summarized by chemical equations, written: Reactants Products NaCl Na + + Cl -
Energy in Chemical Reactions In a chemical reaction, energy is absorbed or released when chemical bonds are broken and new ones are formed. Some chemical reactions release energy Other chemical reactions absorb energy Metabolism: all of the chemical reactions that occur within an organism. Most of our energy comes from the food we eat and digest! When we digest food, chemical reactions convert the chemical energy in food molecules into energy our cells can use.
Activation Energy Activation energy: the energy needed to start a chemical reaction Example: a big rock rolling down the hillto make it roll, you must first push it. The activation energy is a push for chemical reactions! Enzymes are substances (mostly proteins) that increase the speed of chemical reactions (catalysts)
Enzymes Most biochemical reactions (reactions that occur in cells) require activation energy to begin. Chemical reactions can occur quickly and at the low temperature of our body because of enzymes. Enzymes: substances that increase the speed of chemical reactions. Most enzymes are proteins. Enzymes help organisms maintain homeostasis.
Enzyme Specificity Substrate: a substance on which an enzyme acts during a chemical reaction. Enzymes act ONLY on specific substrates. For example, amylase, an enzyme in your saliva, assists in the breakdown of starch to glucose in your food. Enzymes often end with the letters ase so we can figure out that amylase is an enzyme even if weve never heard of it before! An enzymes activity is determined by the shape of the enzyme.
Enzyme Specificity Typically, an enzyme is a large protein with one or more deep folds on the surface. Active sites: pockets in the folds on enzyme surfaces. The substrate of the reaction fits into the active site. An enzyme acts only on a specific substance because only that substrate fits into the active site.
Inhibition: Competitive and Non- Competitive Enzyme function can be inhibited (restrained or checked)in two main ways: Competitive Inhibition: inhibitor that fills the active site of an enzyme and stops the normal substrate from binding (biology-online.org). Non-Competitive Inhibition: Enzyme inhibition in which the inhibiting substance does not compete with the normal substrate for the active site on the enzyme but inhibits reaction by combining with the enzyme-substrate complex after the complex is formed (medical-dictionary.thefreedictionary.com)
Factors in Enzyme Activity Enzymes operate most efficiently within a certain range of temperatures or in a certain pH. Temperatures outside the normal range can break of strengthen some bonds between amino acidsin the enzyme (usually made of protein), changing the shape. If the shape is changed, the active site may also change and the substrate will be unable to bind. pH also impacts enzyme activity. A pH that is too low (acidic) or too high (alkaline) can also break bonds between amino acids, changing the shape of the protein.
Digestion Ch. 39.2
Breaking Down Food Before your body can use the nutrients in food you eat, the large food molecules must be broken down. Digestion: the process of breaking down food into molecules the body can use.
Starting Digestion Digestion of food begins in your mouth. Teeth rip and chew food and mix food in with saliva. Saliva contains amylases. Amylases: enzymes that begin the breakdown of carbohydrates such as starch, into monosaccharides (single sugars). Food then passes through the pharynx into the esophagus.
The Esophagus Esophagus: a long tube that connects the mouth to the stomach. No digestion takes place in the esophagus. Food is moved through the esophagus through peristalsis. Peristalsis: successive rhythmic waves of smooth muscle contractions in the esophagus that moves the food toward the stomach.
The Stomach The stomach is a saclike organ that stores food temporarily and mechanically breaking down food and chemically breaking down proteins. When food enters the stomach, it secretes gastric juice, a mixture of hydrochloric acid and pepsin. Pepsin: a digestive enzyme that breaks protein strands into chains of amino acids.
The Small Intestine Food passes into the small intestine is where carbohydrates are broken down into monosaccharides, proteins into amino acids, and lipids into fatty acids and glycerol. Fats are digested by pancreatic enzymes called lipases, but are first treated with bile which emulsifies the fats (turns them into little drops). Absorption of nutrients occurs in the small intestine through the lining of the small intestine on projections called villi.
The Large Intestine Components of food that are not for energy production are considered wastes. Wastes move into the large intestine, also called the Colon. No digestion takes place in the colon. Most of colons contents are dead cells, mucus, digestive secretions, bacteria, and yeast. Balancing water absorption is an important function of the colon.
The Livers Role in Digestion and Metabolism The liver plays several roles in human digestion and metabolism even though food never enters the liver. The Livers Role in Digestion Secretes bile, which aids in the emulsification of fat and promotes the absorption of fatty acids and fat soluble vitamins A, D, E, and K. The Livers Role in Metabolism The liver stabilizes blood...