Question

		Due to the molecular interactions between lipids and polar molecules, _____. a. water molecules isolate themselves into droplets when mixed with lipids b. lipids readily dissolve in water c. nonpolar lipids will not interact with water d. polar substances pass through a lipid bilayer more readily than nonpolar substances According to cell theory, ____. a. all organisms are multicellular b. all cells come from preexisting cells c. DNA is the structural and functional unit of life d. all cells are approximately the same size The structural formula for molecular oxygen is depicted as O=O. What kind of bond holds molecular oxygen together? a. ionic b. polar covalent c. single covalent d. double covalent What molecule would be considered a covalent compound? a. oxygen (O2) b. sodium chloride (NaCl) c. water (H2O) d. a diamond (C) Which organelle primarily functions in packaging cellular secretions for export from the cell? a. Golgi body b. mitochondria c. lysosome d. ribosome Surface tension is an example of ____. a. hydrophobicity b. concentration c. evaporation d. cohesion The nucleus of an atom contains ____. a. protons only b. electrons only c. neutrons only d. protons and neutrons We can accurately determine the age of a rock or fossil by measuring its ____. a. proton concentration b. electron concentration c. neutron concentration d. isotope concentration Carbon has an atomic number of 6. Carbon-14 has _____. a. 6 neutrons and 6 protons b. 6 neutrons and 8 protons c. 8 neutrons and 6 protons d. 14 neutrons and 6 protons Cell shape is reinforced by ____. a. phospholipids b. DNA c. cytoskeletal filaments d. transport proteins Hydrophobic molecules are ____ water. a. attracted by b. absorbed by c. repelled by d. mixed with Which organelle completes protein modifications and packages the protein for export? a. lysosome b. Golgi body c. peroxisome d. smooth ER Sweating to keep cool in the summer is the result of ____. a. hydrogen bonds breaking to release energy b. hydrogen bonds forming, which requires energy c. evaporation of water giving off energy d. cohesion of water molecules giving off energy Transport proteins _____. a. are found only in eukaryotic cells b. allow only small molecules and ions to cross the membrane c. are required for small nonpolar molecules to cross the membrane d. allow ions and polar molecules to cross the membrane The endoplasmic reticulum is an extension of ____. a. the cytoskeleton b. flagella c. the nuclear envelope d. the plasma membrane Water molecules are attracted to one another because the ____. a. slightly positive charge of the hydrogen atom from one molecule of water attracts the slightly negative charge of the oxygen atom from another molecule b slightly negative charge of the hydrogen atom from one molecule of water attracts the slightly negative charge of the oxygen atom from another molecule c. slightly positive charge of the hydrogen atom attracts the oxygen within the same molecule of water, which leads to an increase in its polarity d. water molecules participate in non-polar covalent bonds, which increase the attraction of the molecules to each other A nucleotide consists of ____. a. a five carbon sugar, a nitrogenous acid, and a phosphate group b. a six carbon sugar, a nitrogenous base, and a phosphate group c. a five carbon sugar, a nitrogenous base, and a phosphate group d. a six carbon sugar, a nitrogenous acid, and a phosphate group Eukaryotic cells have their DNA enclosed in the _____. a. plasma membrane b. nucleus c. nucleoid d. nuclear envelope Because the smooth ER does not contain ____, it cannot produce proteins. a. Golgi bodies b mitochondria c. ribosomes d. DNA Cilia and flagella ____. a. are found only in cells that are actively moving b. are found only in sex cells and unicellular organisms c. use motor proteins to induce movement d. may also function as receptor sites for certain hormones