Bio 121 Exam 2

What step in photosynthesis produces oxygen? A. the splitting of water B. The Calvin Cycle and the formation of glucose C. Carbon fixation D. ATP use in the Calvin cycle

A.

Which of the following is a correct difference between active transport and facilitated diffusion? A. Active transport requires energy from ATP, and facilitated diffusion does not. B. Active transport can move solutes in either direction across a membrane, but facilitated diffusion can only move in one direction. C. Facilitated diffusion can move solutes against a concentration gradient, and active transport cannot. D. Active transport involves transport proteins, and facilitated diffusion does not. E. Facilitated diffusion involves transport proteins, and active transport does not.

A. Active transport requires energy input (ATP hydrolysis) to power the movement of molecules, typically the movement is against the concentration gradient

Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the membrane would carbohydrates most likely be found? A. on the outside (external) surface of the membrane B. in the interior of the membrane C. on both hydrophilic surfaces of the membrane but not in the hydrophobic interior D. Carbohydrates are rarely associated with plasma membranes. E. on the inside (cytoplasmic) surface of the membrane

A. Carbohydrates are added to proteins which face the inside of the Golgi complex. As these membranes fuse with the plasma membrane, the carbohydrates face outward from the cel, forming the extracellular matrix.

Which of the following statements about the sodium-potassium pump is correct? A. The sodium-potassium pump is an antiproton that results in a net negative charge inside the cell. B. The sodium-potassium pump is a symporter that results in a net negative charge outside the cell. C. The sodium-potassium pump moves sodium out of the cell and co-transports protons into the cell, which is the source of energy for the movement of the potassium into the cell. D. The sodium-potassium pump uses an existing proton gradient to drive the movement of sodium and potassium ions. E. The sodium-potassium pump transports Na+ and K+ across the plasma membrane in the same direction at the expense of ATP hydrolysis

A. Sodium (3+) moves out of the cell, and Potassium (2+) moves into the cell. Each of these movements are against the concentration gradient and this requiring active transport. The net result of this transport is a charge difference making the inside of the cell more electronegative.

Which of the following five membranes is the most likely to have a lipid composition that is distinct from the other four? A. mitochondrial outer membrane B. plasma membrane C. lysosome membrane D. endoplasmic reticulum E. Golgi apparatus

A. The mitochondrial membrane originates from the replication/splitting of existing mitochondria. All the other membranes mentioned are formed from movement of lipids away from the endoplasmic membrane, thus they would all have similar composition.

Where are the proteins of the electron transport chain located? A. inside the mitochondrial matrix B. Mitochondrial inner membrane C. cell plasma membrane D. cytosol

B.

Where does light absorption occur in a chloroplast? A. The Mitochondrial membrane B. the thylakoid membrane C. The cytoplasm D. The stroma of the chloroplast

B.

Which of the following is true of glycolysis and the citric acid cycle (oxidative respiration)? A. Glycolysis and the citric acid cycle both occur inside mitochondria. B. An end product of glycolysis is a molecule that can be further metabolized in the citric acid cycle. C. Cells choose to use either glycolysis or the citric acid cycle, depending on conditions. D. Oxidation only occurs during the electron transport chain, not in glycolysis or the citric acid cycle.

B.

Which of the following is true? A. Pyruvate has less free energy than carbon dioxide B. Pyruvate has more free energy than carbon dioxide

B.

Chemiosmosis uses the energy from the sodium gradient across the mitochondrial membrane to synthesize ATP from ADP and inorganic phosphate. A. True B. False

B. The energy for ATP synthesis comes from the proton (hydrogen ion) gradient that is generated during the transfer of electrons along the electron transport chain

How do chloroplasts generate ATP for use in photosynthesis? A. The Calvin Cycle B. The oxidation of NADPH C. The electron transport chain and chemiosmosis D. ATP is not made by chloroplasts

C.

Which molecule collects high energy electrons from glucose and transports them around the mitochondria so that they can eventually be given yo oxygen? A. Glucose B. Water C. NAD+/NADH D. ATP

C.

Which of the following best describes glycolysis? A. Any process that converts glucose into another molecule. B. Any metabolic reaction that is anaerobic and does not involve oxidation/reduction reactions. C. A multistep metabolic process involving multiple enzymes D. A single step process (single reaction) that precedes oxidative respiration

C.

Which of the following must be true of the metabolism of sugar and oxygen into carbon dioxide and water, according to the laws of thermodynamics? A. All of the energy stored in glucose is transferred to ATP. B. Energy is created in the reaction, such that there is more energy in ATP than was present in glucose and oxygen. C. Energy is transferred, but some of it is dissipated as heat D. The reaction progresses due to the decrease in entropy

C.

Which step in photosynthesis uses ATP? A. Synthesis of glucose from glyceraldehyde-3-phosphate (the output of the Calvin Cycle) B. NADPH production C. The Calvin Cycle D. Light reactions

C.

Which of the following statements about cotransport of solutes across a membrane is correct? A. A cotransport protein is most commonly an ion channel. B. Cotransport involves the hydrolysis of ATP by the transporting protein. C. Cotransport proteins allow a single ATP-powered pump to drive the active transport of many different solutes. D. The sodium-potassium pump is an example of a cotransport protein. E. In cotransport, both solutes that are being transported are moving down their chemical gradients.

C. A single ATP powered pump transports hydrogen against it's concentration gradient to the outside of the cell. This hydrogen ion gradient can then be coupled with the transport of several other solutes to provide the needed energy to bring them into the cell

Which of the following structures is found in animal cells but NOT plant cells? A. Golgi apparatus B. rough endoplasmic reticulum C. centrioles D. plasma membrane E. mitochondria

C. Despite a well organized microtubule system the plant cell and some fungi actually lack centrioles

Which of the following best describes substrate-level phosphorylation? A. Production of ATP using an electron transport chain. B. A non-enzymatic process where inorganic phosphate comes out of solution to attach to a substrate. C. An enzymatic process that transfers phosphate from a molecule to ADP D. The hydrolysis of ATP for energy

C. In substrate level phosphorylation, the phosphate that is transferred to form ATP is attached to another molecule, rather than coming from inorganic phosphate.

What best describes oxidation? A. The gain of electrons to a molecule. B. The loss or gain of electrons from a molecule. C. The loss of electrons from a molecule D. Any reaction involving oxygen

C. Oxidation is the loss of electrons from one molecules, and the addition of electrons to a molecule is a reduction

Which of the following statements about diffusion is true? A. It requires expenditure of energy by the cell. B. It occurs when molecules move from a region of lower concentration to a region of higher concentration. C. It is very rapid over long distances. D. It is a passive process E. It always requires integral proteins of the cell membrane

D Requires no energy! Molecules follow a concentration gradient spreading out from a region of high concentration and moving into a region of low concentration.

Which of the following best describes the thermodynamic change when sugar and oxygen are reacted to produce carbon dioxide and water? A. There is no change in free energy B. There is an increase of free energy C. We cannot tell what the free energy change is unless we know the temperature. D. There is a decrease of free energy.

D.

Which of the following enables a cell to pick up and concentrate a specific kind of molecule? A. facilitated diffusion B. osmosis C. passive transport D. receptor-mediated endocytosis E. channel proteins

D. Receptor mediated endocytosis allows a cell to acquire bulk quantities of a specific substance

At body temperature (37 C), a very fluid plasma membrane would be composed of primarily,_____? A. large amounts of cholesterol B. Phospholipids with saturated hydrocarbon tails C. phospholipids which have been glycosylated D. Phospholipids with unsaturated hydrocarbon tails

D. Unsaturated hydrocarbon tails cause the molecule to "kink" thus blocking the phospholipids from packing tightly together. This loose arrangement of phospholipids caused by the unsaturated tails greatly increases membrane fluidity.

Which of the following categories best describes the function go the rough endoplasmic reticulum? A. energy production B. information storage C. breakdown of complex foods D. structural support of cells E. protein production

E. Rough ER is so called because it is decorated with ribosomes. These ribosomes are producing new proteins for the cell which are injected into the ER lumen or span the ER membrane.

What molecule in the plant leaf is responsible for absorbing light for photosynthesis? A. NADPH B. Water C. Glucose D. Thylakoids E. Chlorophyll

E. Chlorophyll