[Brock University] BIOL 1P91 Midterm Exam Questions And Answers

[Brock University] BIOL 1P91 Midterm Exam Questions And Answers The smallest functional unit in living organisms - ANS Atoms The three subatomic particles - ANS protons, neutrons, electrons Where the neutrons and protons are found - ANS The atomic nucleus What was Rutherford's experiment? - ANS A fine beam of positively charged alpha particles (helium nuclei) was aimed at an extremely thin sheet of gold. A zinc sulfide screen was used to detect any alpha particles that passed through or bounced off. What shape are "s" orbitals? - ANS Spherical What shape are "p" orbitals? - ANS Propeller or dumbbell shaped. How many electrons can an orbital hold? - ANS 2 electrons What happens when the outer orbital isn't full? - ANS The tend to share What are valence electrons? - ANS Electrons in the outermost shell What is the atomic number? - ANS The number of protons in the atom What unit is atomic mass measure in? - ANS Daltons What is Avagadro's number? - ANS The amount of atoms in 1 mole (6.022e23) What is different between isotopes? - ANS The number of neutrons What are radioisotopes? - ANS Unstable isotopes What is a major use of radioisotopes? - ANS Modern medicine What are the four main elements of life? - ANS Oxygen, carbon, hydrogen, nitrogen How much of a living organism is made up of the four main elements? - ANS 95% What is a molecule? - ANS Two or more atoms bonded together How do covalent bonds join atoms? - ANS By sharing electrons What is electronegativity? - ANS The measure of it ability to attract electrons in a bond What is a polar covalent bond? - ANS A covalent bond in which electrons are not shared equally What is another word for a polar molecule? - ANS Dipole What is a polar molecule? - ANS Molecules with a significant number of polar bonds What is an ionic bond? - ANS A chemical bond that's formed when an atom transfers and electron to another atom What is a cation? - ANS A positively charged ion What is an anion? - ANS A negatively charged ion What are free radicals? - ANS A molecule containing an atom with a single, unpaired electron in its outer energy shell. [T/F] Free radicals can do considerable harm to living cells. - ANS True When can free radicals be beneficial to living organisms? - ANS When they are used to kill harmful bacteria What is a chemical reaction? - ANS A process that changes, or transforms, one set of chemicals into another What energy is needed for chemical reactions? - ANS Heat What is Brownian motion? - ANS The random movement of particles What is a catalyst? - ANS A substance that speeds up a chemical reaction without being consumed What are Van der Waals forces? - ANS Van der Waals forces cause all atoms and molecules to be attracted to one another. They're caused by temporary dipoles which occur when the moving electrons within a charge cloud are more to one side than the other. Larger molecules or molecules with a greater surface area have more Van der Waals forces. [T/F] Van der Waals forces are stronger than ionic and covalent bonds - ANS False What is an ion-dipole force? - ANS Occurs between ions and polar molecules What is a dipole-dipole force? - ANS Occurs between polar molecules What are hydrogen bonds? - ANS A bond between a hydrogen of one polar molecule and the oxygen, nitrogen, or fluorine of another nearby polar molecule. In biological systems, the hydrogen in a hydrogen bond usually bonds to: - ANS Oxygen, Nitrogen