Download Honors Biology Midterm Reviewаа BASIC CHEMISTRY

Honors Biology Midterm Review BASIC CHEMISTRY: ● Atom­ smallest unit of matter ○ Neutrons(N charge) and protons(+ charge) are packed in the atom’s nucleus ■ The negative charge of electrons(­ charge) and the positive charge or protons keep electrons near nucleus ○ Number of protons is the atom’s atomic number ○ Mass number is the sum of protons and neutrons in the nucleus ○ Same number of protons and electrons but different numbers of neutrons= isotopes ○ Atom may have 1, 2, or 3 electron shells ■ Number of electrons in cell determine chemical properties of atom ■ Want to fill their outer electron shells, and accomplish this by sharing, donating, or receiving electrons, also known as ​
chemical bonds ● Isomers­ different compounds with same molecular formula ● Element­ ​
a substance that cannot be broken down to other substances ○ 92 elements in nature, only a few exist in pure state ○ Trace elements­ ​
25 essential elements ● Compound​
­ a substance consisting of 2 or more different elements combined in a fixed ratio ● Covalent bond​
­ results when atoms share outer­shell electrons ○ A molecule is formed when atoms are held together by covalent bonds ○ Pull for shared electrons= ​
electronegativity ● Ionic bond­ ​
when attraction between 2 ions with opposite charge holds ions together ○ ion­ ​
an atom or molecule with an electrical charge resulting from gain or loss of electrons ■ when electron is lost: positive charge results ■ when electron is gained: negative charge results ● Number of bonds a carbon makes: 4 ○ carbon­based molecules= organic compounds ○ chain of carbon atoms= carbon skeleton ○ compounds composed of only carbon and hydrogen= hydrocarbons ● Functional groups­ ​
affects a biological molecule’s function in a characteristic way ○ Compounds containing functional groups are hydrophilic (water­loving) ○ Function groups are: ■ Hydroxyl group: consists of a hydrogen bonded to an oxygen ■ Carbonyl: carbon linked by a double bond to an oxygen atom ■ Carboxyl: consists of a carbon double­bonded to both an oxygen and hydroxyl group ■ Amino: composed of a nitrogen bonded to 2 hydrogen atoms and the carbon skeleton ■ Phosphate: consists of a phosphorus atoms bonded to 4 oxygen atoms WATER(H20): ● Has atoms with different electronegativities, oxygen attracts shared electrons more strongly than hydrogen ● Pull toward each atom is equal, because each atom has same electronegativity= ​
nonpolar covalent bonds ● Unequal electron sharing= ​
polar covalent bond ● Oxygen atom has slight ­ charge and hydrogen has slight + charge ○ Molecules with unequal distribution of charges= polar molecules ● Heat­ energy associated with movement of atoms and molecules in matter ○ Heat must be absorbed to break hydrogen bonds, heat is released when hydrogen bonds form ○ water has a greater ability to resist temperature change than other liquids ● Temperature­ measures intensity of heat ● When water freezes­ each molecules forms a stable hydrogen bond with 4 neighbors ○ 3­d crystal results with space between water molecules ○ ice is less dense than water, so it floats ● Hydrogen bond ○ Weaker than covalent bonds ○ Water molecules are electrically attracted to oppositely charged regions on neighboring molecules ○ Positively charged region is always a hydrogen atom, and it will share attractions with other electronegative atoms ● Cohesion­​
hydrogen bonding causes molecules to stick together ○ much stronger for water than other liquids ○ Plants depend upon cohesion to help transport water and nutrients up plant ○ surface tension­ a measure of how difficult it is to break surface of liquid(hydrogen bonds are responsible for this) ● Adhesion­ ​
keeps water drops in place, water seems to stick to surface, attraction of water to unlike substance ● Transportation ACIDS, BASES, ETC. ● Acids​
­ chemicals other than water that can contribute H+ to a solution ○ has a higher concentration of H+ than OH­ ● Bases​
­ accept hydrogen ions and remove them from solution ○ reduces H+ concentration ● Solution​
­ a liquid consisting of a uniform mixture of 2 or more substances ○ dissolving agent= solvent ■ Water is versatile solvent (results from its polarity) ○ substance that is dissolved= solute ● pH (potential of hydrogen) scale­​
used to describe whether a solution is acidic or basic ○ ranges from 0 (most acidic) to 14 (most basic) ○ neutral (7)­ neither acidic or basic ● Chemical reaction­​
formation of water from hydrogen and oxygen ○ reactants are converted into product ■ ex: H2 and O2 → H2O ● Neutralization reaction ○ when an acid and a base react to form water and a salt and involves the +​
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combination of H​
ions and OH​
ions to generate water. The neutralization of a strong acid and strong base has a pH equal to 7. ORGANIC CHEMISTRY ● Carbohydrate​
­range from small sugar molecules (monomers) to large polysaccharides (monomers linked together) ●
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Carbon skeleton of monosaccharides vary in length Monosaccharides are main fuels for cellular work 2 monosaccharides can bond together to form a disaccharide in a dehydration reaction Polysaccharides are polymers of monosaccharides Starch­ storage polysaccharide composed of glucose monomers and found in plants Glycogen­ storage polysaccharide composed of glucose, hydrolyzed by animals when glucose is needed Cellulose­ polymer of glucose that forms plant cell walls ○ Cellulose­ polysaccharides used by insects and crustaceans to build exoskeleton ○ Polysaccharides are hydrophilic ● Lipids­​
water insoluble (hydrophobic/ water fearing) compounds that are important in energy storage ●
○ Fats(aka triglycerides) are lipids made from glycerol and fatty acids ■ Fatty acids link to glycerol by a dehydration reaction ○ Fats with maximum number of hydrogens= saturated fats ○ Fatty acids containing double bonds= unsaturated fats ○ Phospholipids­ structurally similar to fats and are important component of all cells ■ Have hydrophilic heads that are in contact with water and hydrophobic tails that band in center of bilayer in cell membranes ○ Steroids­ lipids composed of fused ring structures ○ Cholesterol­ a steroid that plays a significant role in structure of cell membrane ● Proteins​
­ a polymer built from various combination of 20 amino acid monomers ●
○ Enzymes­ proteins that serve as metabolic catalysts, regulate chemical reactions within cells ○ Structural proteins­ provide associations between body parts ○ contractile proteins­ found within muscle ○ defensive proteins­ include antibodies of immune system ○ signal proteins­ hormones ○ receptor proteins­ serve as antenna for outside signals ○ transport proteins­ carry oxygen ○ Amino acids­ building blocks of proteins, have an amino group and a carboxyl group (covalently bonded to a central carbon atom) ■ hydrophobic or hydrophilic ■ link together by enzyme­mediated dehydration reaction to form polymeric proteins ■ covalent linkage of carboxyl group of one amino acid to amino group of other amino acid= peptide bond ■ polypeptide chain­ contains hundreds or thousands of amino acids linked by peptide bonds ○ Shape of proteins determines function ○ Denaturation­ will cause a polypeptide chain to unravel and lose their shape and function ■ can be denatured by changes in salt concentration, pH, and temperature ○ Protein can have 4 levels of structure­ primary, secondary, tertiary, and quaternary ● Nucleic Acids are also part of 4 classes of biological molecules ● Dehydration synthesis​
­ monomers are linked together to form polymers through dehydration reactions, which remove water ○ Polymers are broken by ​
hydrolysis,​
the addition of water ● Polymers​
­ 4 classes of biological molecules containing very large molecules (macromolecules) ○ made from identical building blocks strung together ■ building blocks= monomers PLASMA MEMBRANE STRUCTURE, ETC. ● Plasma Membrane Structure­ ​
composed of phospholipids and proteins ● Described as fluid mosaic ○ Fluid­ proteins can drift about in phospholipid ○ Mosaic­ proteins are embedded in phospholipids ○ Unsaturated fatty acids from phospholipids have kinks in tains that prevents them from packing tightly together, which keeps them liquid ○ Aided by cholesterol wedged in bilayer to keep liquid at lower temp. ○ Contain integrins­ give the membrane a strong framework by attaching to extracellular matrix and cytoskeleton ○ Some glycoproteins in membrane serve as id tags that are recognized by membrane proteins of other cells ○
● Forms of transport across membrane ○ Selectively permeability­ membranes allow some substances to cross or be transported more easily than others ■ nonpolar molecules cross easily ■ polar molecules do not ○ Diffusion​
­ process in which particles spread out evenly in available space ■ particles move from area of more concentrated particles to an area where they are less concentrates ●
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■ Particles diffuse down their concentration gradient and eventually reach equilibrium where concentration of particles is same throughout ■ Passive transport­ does not require energy ■ aquaporins­ transport proteins that help substances diffuse across membrane ■ Facilitated diffusion​
­ type of passive transport that doesn’t require energy ● some proteins function by becoming a hydrophilic tunnel for passage, and others bind to passenger, change shape, and release passenger on other side ○ Osmosis​
­ water moves across membranes in response to solute concentration in and out of cell ■ Osmoregulation­ organisms are able to maintain water balance within their cells Tonicity​
­ ability of a solution to cause a cell to gain or lose water ○ Isotonic­ indicates concentration of a solute is same on both sides ○ Hypertonic­ concentration of a s solute is higher outside of cell ○ Hypotonic­ higher concentration of solute inside cell Active transport­ move substances against concentration gradient ○ requires energy Exocytosis­ ​
used to export bulky molecules Endocytosis​
­ used to import substances useful to the livelihood of the cell ○ Phagocytosis​
­ engulfment of a particle by wrapping cell membrane around it, forming vacuole ○ Pinocytosis­​
fluids taken into small vesicles ○ Receptor­mediated endocytosis­​
when receptors in a receptor coated pit interact with a specific protein, initiating formation of a vesicle Scientific Method​
­ process that uses questioning and evidence to solve problems or answer a question ● Hypothesis writing­ ​
make a short definitive statement that can be proven true or false ○ If...Then ● Control experiment­​
is an experiment that contains only one experimental variable ● Independent variable­​
is the thing being tested ( what scientist changes) ● Dependent variable­​
what changes when the independent variable changes (depends on outcome of independent variable) ○ Both should be organized on a graph ● Negative control​
­ an trial of the experiment in its natural state ○ shows a normal situation ● Positive control​
­ the part of the experiment that receives treatment ○ has a known result, if something doesn’t happen as planned something is wrong with experiment ● Conclusion writing­ ​
may or may not support hypothesis ○ may be quantitative (numbers) or qualitative (appearance, properties, etc) Reactant­​
substance that takes part in or undergoes change during reactions Products­​
end product during a reaction Endergonic­​
requires an input of energy and yields products rich in potential energy ● reactants contain little energy in beginning, but is absorbed from surroundings and stored in covalent bonds of the products ● Photosynthesis makes energy­rich sugar molecules using energy from the sun Exergonic​
­ chemical reaction that releases energy ● reaction releases the energy in covalent bonds of reactants ● burning wood releases the energy in glucose, producing heat, light, carbon dioxide, and water ● Cellular respiration­ releases energy and heat and products, uses energy released to perform works ● Energy coupling​
­ use of exergonic processes to drive an endergonic one ○ energy released during exergonic reaction is used as energy in an endergonic reaction ATP​
­ (adenosine triphosphate) energy currency of cells ● adenine (nitrogenous base), ribose (five­carbon sugar), and 3 phosphate groups ● immediate source of energy that powers most forms of cellular work ● Hydrolysis of ATP­ releases energy by transferring its third phosphate from ATP to another molecule ○ phosphorylation­ going from ADP + P to ATP, energy enters ○ ATP energizes molecules ○ ● ATP renewable energy source ● When energy is released in an exergonic reaction, such as breakdown of glucose, the energy is used in an endergonic reaction to generate ATP Energy of Activation­ ​
the energy that must be available to break bonds to form new ones ● there is a lot of potential energy in biological molecules, it is not released spontaneously­ needs energy of activation Enzymes​
­ proteins that function as biological catalysts (drives or speeds up biological reactions) ● Speeds up the rate of the reaction by lowering energy of activation ● Substrate­​
each enzyme has particular target molecule ● 3­D shape ● Active site​
­ where the enzyme interacts with the enzyme’s substrate ○ substrate’s chemistry is altered to form the product of the enzyme reaction ● Denaturalization​
­ enzymes require certain conditions ○ 37 degrees C, or body temperature ○ pH around neutral for best results ○ Salt concentration can also denature an enzyme ● Inhibitors​
­ stops enzyme activity ○ Competitive ​
inhibitors­ blocks active site so substrate cannot enter ○ Noncompetitive​
inhibitor­ binds somewhere else and changes shape of enzyme so substate no longer fits into active site ● Metabolism​
­ chemical processes occurring within a living cell or organism that are necessary for the maintenance of life ○ some substances are broken down to yield energy for viral processes while other substances, necessary for life, are synthesized