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biology-Ch. 2
| Question | Answer |
|---|---|
| What is an atom? | smallest basic unit of matter |
| What is an element? | substance that cannot be broken down into simpler substances by ordinary chemical means |
| What are all living things based on? | atoms and their interactions |
| What is a compound? | substance with different elements |
| What are ions? | uneven amount of electrons and protons in atom; when an element gains or loses electrons |
| Of the 91 elements that naturally occur on Earth, how many are found in organisms? | |
| What are the four most common elements found in a human body? | Oxygen- 65%,Carbon-18%, hydrogen-10%, nitrogen-3%------96% of human body |
| What are the trace elements? | needed to survive, very few amounts; Calcium-1.5%, Phosphorous-1%, Potassium-.35%, Sulfur-.25%,Sodium-.15% |
| What are covalent bonds? | formed when atoms share a pair of electrons; generally very strong |
| What are ionic bonds? | chemical bond formed through electrical force between oppositely charged ions |
| Explain why hydrogen atom can be either an ion or part of a molecule. | |
| What did Thompson discover? | Electrons |
| What did Rutherford discover? | Atoms have a large, dense nucleus |
| What did Bohr discover? | Energy levels |
| What does life depend on in water? | hydrogen bonds |
| What is a polar molecule? | have region with slightly positive and negative charge; form when atoms in molecule have unequal pulls on electrons they share ex: water |
| What are nonpolar molecules? | share electrons more equally; does not have a charged region |
| What is a hydrogen bond? | attraction between slightly positive hydrogen atom and slightly negative, often oxygen or nitrogen |
| What are the water properties related to hydrogen bonds? | High specific heat:water resists changes in temp.abosrbs heat to regulate cell temp.; cohesion: attraction of molecules between one substance, make molecules stick to one another; adhesion: attraction of molecules between different substances |
| Example of adhesion | helps plants transport water from their roots to leaves bc water molecules stick to sides of vessels that carry water |
| Molecules and ions cannot take part in chemical processes inside cells unless what? | they dissolve in water |
| What is a solution? | mixture of substances that is the same throughout- homogenous mixture |
| What is a solvent? | substance solute dissolves into |
| What is a solute? | substance that dissolves in a solvent |
| What determines a solution's concentration? | amount of solute dissolved in certain amount of solvent |
| What is pH? | measure of acidity; related to free hydrogen ion concentration in solution |
| What is an acid? | compound that donates a proton(H+) when dissolves in a solution. pH: 1-6, sour |
| What is a base? | compounds that remove H+ ions from a solution; when dissolved in water, has low concentration |
| What are carbon based molecules often called? | foundation of life |
| What is carbon often called? | building blocks of life |
| What does a carbon have in its outer energy level? | 4 unpaired electrons |
| What are the three fundamental structures of carbon- based molecules? | straight, branched, ring-shaped |
| What are the four main types of carbon-based molecules found in living things? | carbs, lipids, proteins, amino acids |
| Describe Carbohydrates | main source of energy, make up cell walls in plants, found in fruits, veggies, sugars, animal milk; simple: 1 or 2 monomers, sweet, complex: polymers, starchy. most common monomer carb glucose, shape like hexagonal ring. CHO |
| Describe Proteins | major structural molecules; all cell membranes have protein; found in MEANS: membranes, enzymes, antibodies, nonsteroid hormones, structural molecules; thyroid regulates how fast body uses energy; found in cell membrane,muscle,grain,nuts,fruits veggies |
| Describe proteins contin. | shape: balled up string, made of CHON(S): carbon, hydrogen, oxygen, nitrogen, sometimes sulfur |
| Describe lipids. | source of stored energy, insulate temp, cushions internal organs, produces hormones, waterproof-WISE C; common steroids:cholesterol, sex, anabolic steroids; found in plant seeds, adipose(fatty) tissue, connective tissue, cell membranes |
| Describe lipids contin. | triglycerides'(ester obtained from glycerol by the esterification of three hydroxyl groups with fatty acids, naturally occurring in animal and vegetable tissues) shape=E; made of polymers of monomers |
| Describe lipids contin. | saturated fatty acids have no double bonds and are saturated with hydrogen; unsaturated fatty acids have double bonds; CHO; carbs have twice as many hydrogens than oxygen; lipids have more than twice |
| Describe nucleic acids | two types: DNA- genetic material made of chromosomes, RNA- reads DNA "protein recipes" and makes proteins, found in nucleus of cell, polymers made of monomers; made of nucleotides which is nitrogen base; DNA-double helix, RNA-singular |
| Describe nucleic acids contin. | made of phosphorous, oxygen, nitrogen, carbon, hydrogen PONCH |
| What is a chemical reaction? | changes substances into different ones and forms chemical bonds |
| What are reactants? | substances changed during chemical reaction |
| What are products? | substances made in chemical reaction |
| What is bond energy? | amount of energy that will break a bond between two atoms |
| What is equilibrium? | both reactants and products are made at same rate |
| Exothermic and endothermic reactions. | exothermic-energy is released,products have lower energy than reactants; endothermic-energy is absorbed, higher bond energy than reactants |
| What is activation energy? | energy needs to be absorbed for chemical reaction to start |
| What are enzymes? | catalysts for chemical reactions in living things |
| What is a catalyst? | substance that decreases activation energy and increases reaction rate |
| What are all enzymes usually considered? | proteins |
| When does homeostasis and enzymes function best at? | normal body temp. |
| Who were ribozymes founded by? | Cech and Altman; found in RNA; if enzyme not protein is ribozyme |
| By enzymes switching genes on and off, cells can control metabollic reactions which control metabollism | |
| What does an enzymes shape allow it to do? | allow certain reactants to bond with it. ex: amylase only breaks down starch |
| What are substrates? | specific reactants that an enzyme can act upon |
| What is a lock and key model? | explains how enzymes work, enzymes bring substrates close together and decreases activation energy |
Created by:
kayla26tran
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