BIO 181 - EXAM 02

Which of the following statements is true? A) ATP can have four negative charges. B) ADP contains more energy than ATP. C) Following hydrolysis, ATP can give off one phosphate, whereas ADP cannot. D) ADP can have two positive charges.

A) ATP can have four negative charges.

What compound directly provides energy for cellular work? A) ATP. B) DNA. C) Fat. D) We do not need energy.

A) ATP.

Which organelle is responsible for photosynthesis? A) Chloroplast. B) Smooth Endoplasmic reticulum. C) Ribosome. D) Mitochondrion.

A) Chloroplast.

What is the function of stomata? A) Gas exchange. B) Calvin cycle. C) Location of photosystems. D) Fermentation. E) Water absorption.

A) Gas exchange.

What does the enzyme lactase break down? A) Lactose. B) Starch. C) Amylase. D) Nothing.

A) Lactose.

Which of the following processes includes all of the others? A) Passive transport. B) Osmosis. C) Facilitated diffusion. D) Transport of an ion down its electrochemical gradient.

A) Passive transport.

Which are the primary molecules making up the plasma membrane in cells? A) Phospholipids. B) Proteins. C) Nucleic acids. D) Peptidoglycan.

A) Phospholipids.

What is a substrate? A) The item that binds the enzyme's active site. B) It is the enzyme. C) DNA. D) It is not a real word.

A) The item that binds the enzyme's active site.

Which of the following aspects of enzyme structure is best described by a clasping handshake analogy? A) The specific manner in which an enzyme binds substrate. B) The specific manner in which an enzyme folds to form secondary and tertiary structures. C) The specific manner in which an enzyme interacts with water. D) The specific manner in which an enzyme is denatured by low pH.

A) The specific manner in which an enzyme binds substrate.

Why are lipids and proteins free to move laterally in membranes? A) There are only weak hydrophobic interactions in the interior of the membrane. B) The interior of the membrane is filled with liquid water. C) Lipids and proteins repulse each other in the membrane. D) Hydrophilic portions of the lipids are in the interior of the membrane.

A) There are only weak hydrophobic interactions in the interior of the membrane.

The force driving simple diffusion is ______, while the energy source for active transport is ______. A) a concentration gradient; ATP hydrolysis B) a concentration gradient; ADP C) transmembrane pumps; an electrochemical gradient D) phosphorylated carrier proteins; ATP

A) a concentration gradient; ATP hydrolysis

For a protein to be an integral membrane protein, it would have to be ______. A) amphipathic, with at least one hydrophobic region B) hydrophilic C) hydrophobic D) exposed on only one surface of the membrane

A) amphipathic, with at least one hydrophobic region

Plant cells, unlike animal cells, are characterized by the presence of a ______. A) cell wall and central vacuole B) cell wall and contractile vacuole C) nucleus and cell wall D) nucleus and contractile vacuole

A) cell wall and central vacuole

One difference between eukaryotic and prokaryotic cells is that eukaryotic cells ______ prokaryotic cells. A) have membrane-enclosed structures called organelles, which are lacking in B) have a plasma membrane, which is lacking in C) have a nucleoid region, which is lacking in D) have DNA, which is lacking in

A) have membrane-enclosed structures called organelles, which are lacking in

A sodium-potassium pump ______. A) moves three sodium ions out of a cell and two potassium ions into a cell using energy from ATP hydrolysis B) moves three potassium ions out of a cell and two sodium ions into a cell while producing ATP for each cycle C) moves three potassium ions out of a cell and two sodium ions into a cell using energy from ATP hydrolysis D) move three sodium ions out of a cell and two potassium ions into a cell and generates an ATP in each cycle

A) moves three sodium ions out of a cell and two potassium ions into a cell using energy from ATP hydrolysis

Usually, enzymes are ______. A) proteins B) steroids C) fats D) chemical reactions

A) proteins

Which of the following statements about enzyme function is true? A) Enzyme function is generally increased if the three-dimensional structure or conformation of an enzyme is altered. B) Enzymes increase the rate of chemical reactions by lowering activation energy barriers. C) Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. D) Enzymes increase the rate of chemical reactions by providing activation energy to the substrate.

B) Enzymes increase the rate of chemical reactions by lowering activation energy barriers.

The sun helps plants transform carbon dioxide into a simple carbohydrate called? A) Cellulose. B) Glucose. C) Fructose. D) Maltose.

B) Glucose.

Which organelle is ultimately responsible for breaking down carbohydrates into usable energy at the molecular level? A) ATP. B) Mitochondria. C) Ribosomes. D) Golgi apparatus.

B) Mitochondria.

What are the pores in a plant's skin called? A) Stigmata. B) Stomata. C) Stamen. D) Strivia.

B) Stomata.

Enzymes catalyze the many reactions in a cell. There are hundreds of different enzymes in a cell—each with a unique three-dimensional shape. Why do cells have so many different enzymes? A) Each enzyme molecule can be used only once. B) The shape of the enzyme's active site generally fits a specific substrate. C) The substrate molecules react with enzymes to create new enzymes. D) Enzymes are randomly produced. With thousands of different shapes, one is likely to work.

B) The shape of the enzyme's active site generally fits a specific substrate.

______ store the information necessary to produce proteins. A) lysosome B) genes C) ribosomes D) carbohydrates

B) genes

According to the fluid mosaic model, a membrane ______. A) is composed of a fluid bilayer of phospholipids between two layers of hydrophilic proteins B) is composed of a fluid bilayer of phospholipids with embedded amphipathic proteins C) is composed of a single layer of fluid phospholipids between two layers of hydrophilic proteins D) is composed of a mosaic of fluid polysaccharides and amphipathic proteins

B) is composed of a fluid bilayer of phospholipids with embedded amphipathic proteins

The voltage across a membrane is called the ______. A) chemical gradient B) membrane potential C) osmotic potential D) electrochemical gradient

B) membrane potential

The light reactions of photosynthesis convert ______ energy to ______ energy. A) chemical . . . electrical B) solar . . . chemical C) proton gradient . . . chemical D) ATP . . . NADPH E) electrical . . . solar

B) solar . . . chemical

On average, what percentage of the food we eat on a daily basis comes from carbohydrates? A) 20%. B) 40%. C) 60%. D) 80%.

C) 60%.

The Calvin cycle requires ______ and ______ from the light-dependent reactions in order to operate. A) electrons . . . NADH B) RuBP . . . NADP+ C) ATP . . . NADPH D) oxygen . . . carbon dioxide E) glucose . . . carbon dioxide

C) ATP . . . NADPH

If a plant appears blue to us, what wavelength of light is being reflected? A) Yellow. B) Red. C) Blue. D) Green.

C) Blue.

In which organelle does photosynthesis take place? A) Rough endoplasmic reticulum. B) Vacuole. C) Chloroplast. D) Mitochondrion. E) Nucleus.

C) Chloroplast.

Which of the following statements correctly describes osmosis? A) Osmosis only takes place in red blood cells. B) Osmosis is an energy-demanding or "active" process. C) In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration. D) In osmosis, solutes move across a membrane from areas of lower water concentration to areas of higher water concentration.

C) In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration.

Which of the following is a primary function of the active site of an enzyme? A) It binds allosteric regulators of the enzyme. B) It binds noncompetitive inhibitors of the enzyme. C) It catalyzes the reaction associated with the enzyme. D) It is activated by the presence of the end product of the metabolic pathway in which the enzyme is involved.

C) It catalyzes the reaction associated with the enzyme.

Which of the following is an autotroph? A) Human. B) Fish. C) Pine tree. D) Porcupine. E) Mushroom.

C) Pine tree.

Which of the following is a function of the Golgi apparatus? A) Digestion of organic matter inside the cell. B) Drug detoxification. C) Protein modification. D) Protein synthesis.

C) Protein modification.

Substances that plug up an enzyme's active site are ______. A) enzyme substrates B) induced fit factors C) enzyme inhibitors D) enzyme products

C) enzyme inhibitors

A ______ protein is fully on one side or the other of the cell membrane. A) transmembrane B) integral C) peripheral D) normal

C) peripheral

Which of the following equations best summarizes photosynthesis? A) 6 O2 + 6 H2O → C6H12O6 + 6 CO2. B) 6 CO2 + 6 H2O + 6 O2 → C6H12O6. C) 6 CO2 + 6 O2 → C6H12O6 + 6 H2O. D) 6 CO2 + 6 H2O → C6H12O6 + 6 O2. E) C6H12O6 + 6 O2 → 6 CO2 + 6 H2O.

D) 6 CO2 + 6 H2O → C6H12O6 + 6 O2.

What's another name for cellulose? A) Sodium chloride. B) Corn syrup. C) Table sugar. D) Fiber.

D) Fiber.

Which of the following is not a characteristic of the plasma membrane? A) Contains different types of proteins. B) It is easily crossed by small non-polar molecules. C) It is composed of a phospholipid layer. D) Maintains cell shape.

D) Maintains cell shape.

Photosynthesis contributes to plant growth by ______. A) releasing the energy in cellulose to make new leaves and roots B) synthesizing carbon dioxide and making cellulose C) converting sugar to oxygen and water D) taking in oxygen and making wood E) taking in carbon dioxide and making sugars (carbohydrates)

E) taking in carbon dioxide and making sugars (carbohydrates)

What is an enzyme? A) DNA. B) We don't have enzymes. C) Carbohydrates. D) Proteins.

D) Proteins.

Through what structure(s) do plants obtain most of their water? A) Leaves. B) Stems. C) Stomata. D) Roots. E) Interior cells.

D) Roots.

What name is given to the membranous sacs found within a chloroplast? A) Stroma. B) Vesicles. C) Cristae. D) Thylakoids. E) Reaction centers.

D) Thylakoids.