Biology SAT II E/M
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71 terms
Terms | Definitions |
|---|---|
 electrons are in the ground state when... | Electrons are in the lowest available energy level |
| electrons are in the excited state when... | Electrons move to higher energy levels when atoms absorb energy |
| Atoms of one element that vary only in the number of NEUTRONS in the nucleus | Isotopes |
| Isotopes that are radioactive (eg Carbon-14) | Radioisotopes |
| The nuclei of radioisotopes emit particles and decay at the rate known as a... | Half-life |
| When two atomic nuclei attract the same electrons... | a bond is formed |
| Energy is released when... | bonds are formed |
| To break a bond, energy must be... | supplied or absorbed |
| Atoms bond to achieve... | stability |
| There are two main types of bonds... | ionic and covalent |
| Atoms are stable when they have a... | completed outer shell |
| When electrons are transferred, what forms? | an ionic bond |
| An atom that gains electrons is an... | anion or negative ion |
| An atom that loses an electron is a... | cation or positive ion |
| Ions are necessary for... | normal cell, tissue, and organ function |
| Covalent bonds form when... | atoms share electrons |
| Atoms bonded together with covalent bonds are called... | molecules |
| Two atoms sharing one pair of electrons | a single covalent bond |
| Two atoms sharing two pairs of electrons | a double covalent bond |
| Two atoms sharing three pairs of electrons | a triple covalent bond |
| There are two types of covalent bonds... | nonpolar and polar |
| Unbalanced molecules are... | polar |
| Balanced molecules are... | nonpolar |
| The negative end of one polar molecule attracts the... | positive end of another polar molecule |
| H20 is a ____ molecule | polar or unbalanced |
| What keeps the two strands of DNA bonded together, forming a double helix, and causes water molecules to stick together? | Hydrogen bonding |
| The attractions between nonpolar molecules are... | weak |
| Polar substances ______ in water | Dissolve |
| Nonpolar substances _____ in water | don't dissolve |
| Hydrophobic substances... | don't dissolve in water |
| Hydrophilic substances... | dissolve in water |
| Hydrophilic | Polar |
| Hydrophobic | Nonpolar |
| Water's symmetry | asymettric |
| Water has a ____ specific heat, which means it ____ | high, absorbs heat and resists temperature changes |
| Water has a ____ vaporization heat, which means it needs ____ heat for evaporation | high, a lot |
| Water has ____ adhesion properties | high |
| Water dissolves all _____ and ____ substances | polar and ionic |
| Water exhibits ___ cohesion tension, which means... | high, the molecules of water stick together |
| Anything with a pH of less than 7 is | Acidic |
| Anything with a pH value greater than 7 is | alkaline or basic |
| A solution of a pH 1 is ___ times more acidic than a solution of a pH 2 | 10 |
| Organic compounds are compounds that contain... | carbon |
| The four classes of organic compounds are... | carbohydrates, lipids, proteins, and nucleic acids |
| Carbohydrates consist of 3 elements: | carbon, hydrogen, and oxygen |
| The 3 classes of carbohydrates are: | monosaccharides, disaccharides, and polysaccharides |
| All monosaccharides have a chemical formula of | C6H12O6 |
| Glucose, galactose, and fructose are... | monosaccharides |
| Compounds with the same molecular formula with different structures, and physical and chemical properties | Isomers |
| All disaccharides have the chemical formula: | C12H22O11 |
| The breakdown of a compound | Hydrolysis |
| The opposite of dehydration synthesis | Hydrolysis |
| Cellulose, starch, chitin, and glycogen are: | polysaccharides |
| Fats, oils, and waxes are: | lipids |
| A hydrocarbon chain with a carboxyl group at one end | Fatty acid |
| Fatty acids exist in two varieties: | saturated and unsaturated |
| saturated fats come from | animals |
| Saturated fats are ___ at room temperature | Solid |
| Butter is a | saturated fat |
| Unsaturated fatty acids are extracted from | plants |
| Unsaturated fatty acids are ___ at room temperature | liquid |
| Unsaturated fatty acids have at least one | double bond between carbon atoms in the hydrocarbon chain |
| Unsaturated fatty acids have ___ hydrogen atoms than saturated fats | fewer |
| Lipids are used for | energy storage, structure (cell membrane), and endocrine (hormones) |
| Polymers or polypeptides of repeating units called amino acids joined by peptide bonds | proteins |
| A carboxyl group, amine groups, and variable ("R") attatched to a central carbon atom | Amino acids |
| Proteins are complex macromolecules responsible for... | growth and repair |
| proteins consist of the elements | S P C O H N |
| there are ___ amino acids | 20 |
| Proteins | enzymes membrane channels hormones |
| Primary structure | the sequence of amino acids that make up the protein chain |
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