Biology Chapter 6 Study guide – Flashcards
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Elements
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basic chemical units that cannot be broken apart by chemical process.
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How many naturally occuring elements are there?
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90
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How many elements are required by living things?
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25
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What elements is 96% of the human body composed of?
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Oxygen, Hydrogen, Carbon, and Nitrogen
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Trace element
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critical elements found in the body in very small amounts.
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What is an e xample of a trace element?
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Iron
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Each element consists of how many atoms?
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one
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atom
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The smallest particle of an element that has the characteristics of that element.
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Nucleus
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center of the atom
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Electron shells`
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surround the nucleus at different energy levels
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Proton
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positive charge- in nucleus
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Neutron
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0 charge (nuetral) - in nucleus
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Electron
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Negative charge- orbits nucleus
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What kinds of charges attract?
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positive and negative
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What is the greatest number of electrons in the first shell?
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2
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Isotope
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Atoms of the same element that have different numbers of neutrons.
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Unstable isotopes are what?
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Radioactive
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What can happen to the nucleus of an unstabble isotope?
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It can decay spontaneously
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What can happen to the particles and energy of an unstable isotope?
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They can be given off.
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Compound
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2 o r more elements in a fixed ratio that are chemically combined.
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Covalent bonds
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Occur w hen 2 atoms share one or more pairs of electrons forming molecules.
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Molecule
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a group of atoms held together by covalent bonds having no overall charge.
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ionic bonds
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Attracting force between 2 ions of opposite charges
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Ion
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An atom that has gained or lost an electron
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The resulting compound of an ion is what?
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Electrically neutral.
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Starting materials i n chemical reactions
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Reactants
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Resulting material
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products
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MAtter is not created or destroyed but ___.
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Rearanged.
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Fluid
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mixture of 2 or more substances, consisting of a solvent and a solute.
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Solute
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Chemical that causes another substance to dissolve in a solution.
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Solvent
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The substance in a solution that is dissolved
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Acid
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Any substance that forms hydrogen ions in water
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Base
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Any substance that forms hydroxide ions in water.
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OH combines with H+ to form what?
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H2O
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pH scale
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Describes the acidity of solutions
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pH
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Potentital hydrogen
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0 on pH scale
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Most acidic
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14 on pH scale
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Most basic
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pH of 7 is ___.
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Neutral
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Electronegative
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An atom's attraction for shared electrons
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In water, ____ is electronegative
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Oxygen
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The oxygen in H2O forms what?
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Polar covalent bonds
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Polar covalent bonds
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Shared electrons are pulled closer to the more electronegative atom.
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The oxygen in H2O has a slightly what and 2 slightly what?
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Negagative pole, positive poles
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Hydrogen bonds in H2O are _____ chemical bonds.
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Weak
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Hydrogen bonds in H2O cause ______.
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Cohesion
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Cohesion
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making water molecules stick together
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Hydrogen bonds in H2O gives water a high_____.
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surface tension
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High surface tension
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A measure of the d ifficulty to stretch or break the surface of a liquid.
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Hydrogen bonds in H2O also cause _____.
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Adhesion
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Adhesion
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An attraction between molecules of different substances
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Water resists temperature changes and acts as an ____ that helps maintain a steady environment.
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Insulator
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Water ____ when it freezes.
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Expands
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Ice floats where?
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On top
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Water also helps to form _______.
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New soil.
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Diffusion
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movement of molecules from an area of higher concentration to an area of lower concentration.
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All moving objects have _____.
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Kinetic energy
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Kinetic energy
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molecules are in motion
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Brownium motion
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The random motion of molecules
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True/False: Diffusion requires energy.
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False.
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What 3 things is diffusion affected by?
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Concentration, Temperature, and pressure.
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Osmosis
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Diffusion of water molecules
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Temperature can do what to molecules?
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Slow them down or speed them up.
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Organic compounds
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Compounds made by cells that contain carbon.
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Carbon completes it's outer shell by doing what?
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Sharing electrons
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Hydrocarbons
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Compounds composed of only hydrogen and carbon
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Carbon skeleton
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Chain of carbon atoms in organic molecules
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Carbon skeletons can vary in ____.
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Length
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True/false: Carbon skeletons can be branched and unbranched.
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True
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Carbon skeletons can have ______ bonds, varying in locations.
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Double
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Carbon skeletons may be arranged in _____.
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Rings
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Macromolecules
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Giant molecules
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Smaller units of macromolecules:
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Monomers
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Larger units of macromolecules
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polymers
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Chains of monomers
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Polymers
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Macromolecules are formed by ______.
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Condensation.
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Macromolecules are broken by:______.
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Hydrolysis
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Hydrolysis
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A method by which polymers can be broken apart.
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How is each element identified?
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By a symbol
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How many electrons can the second energy level hold?
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8 electrons
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How many electrons can the third energy level hold?
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18 electrons
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True/false: atoms contain different amounts of protons and electrons.
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False
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Metabolism
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All of the chemical reactions that occur within an organism
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Reactants
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Substances that undergo chemical reactions.
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Products
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Substances formed by chemical reactions
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Chemical equations must always be written so that they are _____.
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Balanced
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When elements combine to form compounds, do the elements take on new characteristics, or do they keep the original characteristics?
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They no longer have their original properties.
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Mixture
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A combination of substances in which the individual components retain their own properties.
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What percent range does water make up of organisms?
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70 to 95 percent
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When atoms in a covalent bond do not share electrons equally, they form what?
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a polar molecule
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polar molecule
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a molecule with an uneual distribution of charge
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Dynamic Equilibrium
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Continuous movement but no overall concentration change
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How many electrons does Carbon have in its outer energy level?
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4
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How is a double bond of Carbon formed?
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Each atom shares 2 electrons.
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isomers
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Compounds with the same simple formula but different three dimensional structures.
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Whats an example of 2 isomers?
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Glucose and fructose
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What are the 4 classes of Macromolecules?
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Carbohyrdates, lipids, proteins, and Nucleic acids.
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Carbohydrates range from______.
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Small sugar molecules to large polysaccharides.
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What are the monomers of Carbohydrates?
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Monosaccharides
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What is the function of Carbohydrates?
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They are the main source of energy
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What 3 elements make up Carbohydrates?
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Carbon, hydrogen, oxygen.
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What are the 2 polymers of Carbohydrates?
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Polysaccharides and Disacharrides
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What are 5 examples of Carbs?
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Glucose, Starch, Cellulose, Glycogen, Sucrose
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Dissacharide
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A double sugar formed from 2 monosaccharides by dehydration synthesis.
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Polysaccharides
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Long chains of sugar units linked together by dehydration synthesis.
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Polysaccharides can also be _____that cells break down to obtain sugar.
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Storage molecules
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Starch
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Long term storage in plant roots and other tissues.
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2 examples of starches?
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Potatoes and grains
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Glycogen
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Long term energy storage in animals.
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Where is glycogen stored in animals?
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In the liver and muscle cells.
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Cellulose
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forms cable like fibrils in the tough walls that enclose plant cells.
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Cellulose is a major component of what 2 things?
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Wood and paper
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Lipids
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fats
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What 2 elements do lipids mainly consist of?
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Carbon and Hydrogen atoms linked by nonpolar covalent bonds
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Hydrophobic
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Water fearing
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True/false: Lipids are hydrophobic.
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True
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What are the 2 main functions of lipids?
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Energy storage and cell membranes
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What is the most common type of lipid?
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Glycerol + 3 fatty acids
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Glycerol
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A 3 carbon molecule that serves as a backbone for the lipid molecule.
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Unsaturated
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fats that have double bonds; do not solidify at room temperature
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What kind of fats are unsaturated?
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plant fats
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Saturated
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fats with the maximum number of hydrogen; solid at room temperature
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What kindsof fats are saturated?
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Animal fats
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phospholipids
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Major component of cell membranes
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What are the 3 monomers of Lipids?
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Fat, Phospholipid, Chlesterol/steroids
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What are 4 examples of lipids?
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Unsaturated fats, Saturated fats, Estrogen, Testosterone
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Proteins
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Essential to the structures and activities of life.
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What is the monomer of Protein?
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Amino acids (20 of them)
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What elements make up proteins?
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Carbon, hydrogen, oxygen, nitrogen, and usually sulfur.
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What is the function of proteins?
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Energy, Transport, structure
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What are amino acids?
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Have a central Carbon covalently bonded to 1 hydrogen, 1 amino group, 1 carboxyl group, and 1 chemical group.
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How are amino acids linked together?
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Dehydration synthesis.
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Covalent linkage of amino acids form what?
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A polypeptide bond
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What is the polymer of proteins?
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Polypeptide
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What breaks apart polypeptides?
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Hydrolysis
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Enzymes
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a protein that can change the rate of a reaction. (chemical catalyst)
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Enzymes change the _____ of chemical reactions without chemically changing itself.
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rate
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What are 4 examples of proteins?
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Enzymes, Hemoglobin-blood, Actin, Nyosin-muscle
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Nucleic acid
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a complex macromolecule that stores celluslar information in the form of a code.
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What 5 elements make up nucleic acids?
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Carbon, hydrogen, oxygen, nitrogen, phosphorus
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What is the function of nucleic acids?
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They store genetic information
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What are the 2 types of nucleic acids?
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DNA and RNA
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DNA
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genetic material inherited from parents
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What are the monomers of nucleic acids?
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Nucleotides (5 of them)
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What are the 3 parts of a nucleotide?
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5 Carbon sugar, phosphate group, nitrogenous base
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What are the 5 different nucleotides?
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Adenine, Guanine, Thymine, Cytosin, and Uracil (only in RNA)
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DNA is what shape?
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A double helix
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What is t he polymer of Nucleic acid?
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Nucleic acids
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What are 2 examples of nucleic acids?
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DNA and RNA
