Bio Keystone study pt 1

which statement best describes how channel and carrier proteins in the plasma membrane are similar? A. both allow for the flow of molecules into and out of the cell B. both directly connect the membrane to the nucleus of the cell C. both use energy to continuously move water molecules out of the cell D. both cause the phospholipid bilayer to form a rigid membrane for except

A. both allow for the flow of molecules into and out of the cell

which action must occur for an enzyme to catalyze a chemical reaction? A. a competitive inhibitor must first bind an active site B. a substrate must bind to an active site of the enzyme C. a substrate must bind to an allosteric site of the enzyme D. a noncompetitive inhibitor must first bind to an active site

B. a substrate must bind to an active site of the enzyme

which statement correctly describes ow protein is formed? A. A monosaccharide bonded to a side chain is broken apart B. amino acids are bonded together in a long chain to form a new molecule C. a molecule containing glycerol bonded to three fatty acids is broken apart D. a nitrogenous base, a sugar, and a phosphate group combine to form a new molecule

B. amino acids are bonded together in a long chain to form a new molecule

A lipase is an enzyme that breaks down lipids in the digestive system of humans. it functions best at a pH range of 4.0 to 5.0. when a person take an antacid tablet to relieve heartburn, the antacid increase the pH to around 7 in certain areas of the digestive system. which initial effect would most likely be cause by a change in pH? A. more lipids would be digested B. fewer lipids would be digested C. the production of lipase molecules would increase D. the production of lipase molecules would decrease

B. fewer lipids would be digested

carbon can combine with many different elements but frequently combines with oxygen, hydrogen, and nitrogen to form organic molecules. which statement best explains why carbon is able to form a large number of different molecules? A. carbon forms only ionic bonds B. carbon can form only ring structures C .carbon can form four covalent bonds D. carbon forms small, simple structures

C .carbon can form four covalent bonds

Which characteristic is shared by both prokaryotes and eukaryotes? A. have organ systems B. make their own food C. contain genetic material D. need oxygen gas to breathe

C. contain genetic material

a cell in the leaf of a green plant performs both photosynthesis and cellular respiration, often at the same time. Which statement best describes how these processes are related to each other? A. both processes produce carbon dioxide B. both processes require energy directly from the Sun C. products of one's process are used as some of the reactants for the other process D. remote energy from one processes used as the energy source for the other process

C. products of one's process are used as some of the reactants for the other process

a scientist observed that during the course of a chemical reaction the number of ATP molecules was reduced. what did the scientist most likely learn from the observation? A. the reaction produced water B. the reaction consumed water C. the reaction caused an output of energy D. the reaction required an input of energy

D. the reaction required an input of energy

Given the properties of the medicine Y molecule, which mechanism is most likely responsible for medicine Y's entry into the cells?

active transport

which cell process is best modeled by the diagram?

exocytosis

structure: a molecule made mostly of carbon with two nonpolar chains and a polar head. cellular use: is a component of plasma membranes

lipid

structure: a polar molecule made of repeating units of sugar bonded to a phosphate and nitrogenous base cellular use: stores genetic information

nucleic acid