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Macromolecules
Tonicity
Transport
The Cell
Stuff
100
Which of the following is NOT a polymer? a. DNA b. starch c. glucose d. amylase (an enzyme)
Glucose
100
Differences in cell structure between plant and animal cell result in different effects of osmosis. Which of the following statements is true? a. The plant cell wall prevents cell lysis when in hypotonic solutions. b. Plant cells are healthiest when in isotonic solutions. c. Animal cells plasmolyze in hypertonic solutions. d. Animal cells will swell and possibly lyse when placed in hypertonic solutions. e. None of the above, all the statements are false.
a. The plant cell wall prevents cell lysis when in hypotonic solutions.
100
Transport processes across cellular membranes that require proteins are ________. a. active transport b. diffusion and facilitated diffusion c. facilitated diffusion d. facilitated diffusion and active transport e. diffusion
d. facilitated diffusion and active transport
100
Which of the following relationships between cell structures and their respective functions is not correct? a. cell wall: support, protection b. chloroplasts: chief sites of cellular respiration c. chromosomes: genetic control information d. ribosomes: site of protein synthesis e. mitochondria: formation of ATP
b. chloroplasts: chief sites of cellular respiration
100
Which of the following solutions has the greatest concentration of hydroxide ions? a. human blood at pH 7.0 b. Coke-Cola at pH 3 c. gastric juice at pH 2 d. household ammonia at pH 11.5 e. rain water at pH 5.0
d. household ammonia at pH 11.5
200
The R group or side chain of the amino acid serine is –CH2-OH. The R group or side chain of the amino acid alanine is -CH3. Where would you expect to find these amino acids in a globular protein in aqueous solution? a. Serine would be in the interior, and alanine would be on the exterior of the globular protein. b. Alanine would be in the interior, and serine would be on the exterior of the globular protein. c. Both serine and alanine would be in the interior of the globular protein. d. Both serine and alanine would be on the exterior of the globular protein. e. Cannot determine, the R group does not have any effect on its location in a protein.
b. Alanine would be in the interior, and serine would be on the exterior of the globular protein.
200
Plant cells are healthiest when in ________ solutions and animal cells are healthiest when in ________ solutions. a. isotonic ………………….… hypotonic b. hypotonic ……………..…… isotonic c. hypotonic ………………….. hypotonic d. isotonic ……………………. isotonic e. hypertonic …………………..isotonic
b. hypotonic ……………..…… isotonic
200
Glucose (a monosaccharide) enters most cells by facilitated diffusion. This being the case, which of the following statements is true? a. Glucose is a polar molecule and cannot diffuse across the hydrophobic core of a membrane without the aid of a transporter protein. b. Glucose is transported into the cell when there is a higher glucose concentration outside the cell then inside the cell. c. Glucose transport requires transporter proteins and energy. d. Both A and B. e. Statements A, B, and C are all true.
d. Both A and B.
200
Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and steroids? a. lysosome b. contractile vacuole c. smooth endoplasmic reticulum d. mitochondrion e. ribosome
c. smooth endoplasmic reticulum
200
The climate modifying property of lakes and oceans is due to waters ____. a. density b. surface tension c. boiling point d. high specific heat e. all of the above
d. high specific heat
300
Which of the following descriptions best fits the class of molecules known as nucleotides? a. a nitrogenous base and a phosphate group b. a nitrogenous base and a pentose sugar c. a nitrogenous base, a phosphate group, and a pentose sugar d. a phosphate group and an adenine or uracil e. a pentose sugar and a purine or pyrimidine
c. a nitrogenous base, a phosphate group, and a pentose sugar
300
When limp celery stalks are placed in a bowl of tap water, the stalks become firm within hours. Which statement best describes why this happens. a. Limp celery cells are hypertonic to tap water and water enters the cells. b. Limp celery cells are hypotonic to tap water and water enters the cells. c. Limp celery cells are isotonic to tap water and water enters the cell. d. Limp celery cells are hypertonic to tap water and water exits the cells. e. Limp celery cells are hypotonic to tap water and water exits the cells.
a. Limp celery cells are hypertonic to tap water and water enters the cells.
300
Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells? a. simple diffusion b. osmosis c. active transport d. facilitated diffusion e. not enough information to determine
d. facilitated diffusion
300
If all the lysosomes within a cell suddenly ruptured, what would be the most likely result? a. There would be no change in cell function. b. The mitochondria and chloroplasts would divide. c. More proteins would be made. d. The DNA within mitochondria would break down. e. The macromolecules in the cytosol would begin to break down.
e. The macromolecules in the cytosol would begin to break down.
300
The solutions in the arms of a U-tube are separated by a selectively permeable membrane. The membrane is permeable to water but not to glucose. Side A is filled with a solution of 0.4 M glucose and side B is filled with a solution of 0.8 M glucose. Initially, the volume in both arms is the same. At equilibrium the water level ____. a. in side A will be higher than side B b. in side A will be lower than side B c. in side A will be the same as side B d. not enough information to determine
b. in side A will be lower than side B
400
Ribulose is a saccharide that is an important precursor molecule for photosynthesis. Its structural formula is shown, how can this sugar be classified? a. It is a hexose and aldose. b. It is a disaccharide. c. It is a pentose and ketose. d. It is a pentose and aldose. e. It is a hexose and ketose.
c. It is a pentose and ketose.
400
Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are a. hypotonic to both fresh water and the salt solution. b. hypertonic to both fresh water and the salt solution. c. hypertonic to fresh water but hypotonic to the salt solution. d. hypotonic to fresh water but hypertonic to the salt solution. e. isotonic with fresh water but hypotonic to the salt solution.
c. hypertonic to fresh water but hypotonic to the salt solution.
400
Which of the following statements about osmosis is false? a. Osmosis is a special case of passive transport. b. The solution with the higher concentration of solutes is hypertonic. c. Water molecules will move from the hypotonic solution to the hypertonic solution. d. When two solutions are isotonic, water molecules cease all movement through the membrane. e. Plant cells that are isotonic are flaccid.
d. When two solutions are isotonic, water molecules cease all movement through the membrane.
400
The presence of cholesterol in the plasma membranes of some animals a. decreases membrane fluidity at warm temperatures. b. enables the membrane to stay fluid more easily when cell temperature drops. c. Both A and B. d. None of the above, cholesterol is not found in plasma membranes.
c. Both A and B.
400
The figure at right shows the effect of pH on the activity of the enzymes pepsin, amylase, and arginase. Each enzyme has different substrates. Solution 1 has equal amounts of all three substrates for the three enzymes. Solution 2 has equal amounts of all three enzymes. The most direct way to convert solution 1 to contain only pepsin substrate (removing the substrates for amylase and arginase) is to adjust the pH of solution 1 to ___ and add the enzymes from solution 2. a. 2 b. 4 c. 5 d. 8 e. 10
d. 8
500
Consider this fragment of a polypeptide. Which of the labeled atoms can be involved in secondary structure? a. circled atoms B and D b. circled atoms C and D c. all circled atoms d. circled atoms B e. circled atoms A
a. circled atoms B and D
500
Diffusion moves molecules ________ their concentration gradient ____ added energy. a. down ……………. with b. down ……………. without c. against ……………. with d. against ……………. without
b. down ……………. without
500
Plants synthesize large amounts of glucose and sucrose in green leaves. These sugars are transported out of the chloroplasts into the phloem (the vascular system in plants). What type of transport process would you expect if the sugars are transported out of the chloroplasts as soon as they are synthesized into the phloem? a. Facilitated diffusion because the sugars are polar and need to be transported from low to high concentration into the phloem. b. Diffusion because the sugars are nonpolar and do not need a transport molecule. c. Facilitated diffusion because the sugars are polar molecules that need to be transported from high to low concentration into the phloem. d. Active transport because the sugars are transported from low to high concentration into the phloem.
d. Active transport because the sugars are transported from low to high concentration into the phloem.
500
The pancreas is an organ found in many animals. It synthesizes and secretes a large quantity of protein hormones. You would expect a pancreas cell to have a large quantity of _______. a. mitochondria b. peroxisomes c. endoplasmic reticulum and Golgi apparatus d. chloroplasts e. lysosomes
c. endoplasmic reticulum and Golgi apparatus
500
In a research article printed in Medicine and Biology, 2006,”The Electron-microscopic findings on the liver in chronic abuse of heroin” the authors found that the most prominent changes in cellular organelles was the enlargement and increase number of smooth endoplasmic reticulum. Which of the following statements most likely explains this observation? a. The smooth ER houses many hydrolytic enzymes to degrade molecules. b. The smooth ER functions in cellular respiration needed to provide increased energy needs due to drug toxicity. c. The smooth ER synthesizes sugar molecules needed to provide for the increased energy needs due to illegal drug use. d. One of the functions of the smooth ER is detoxification. e. The smooth ER packages vesicles needed for secretion to other cells damaged by high levels of toxic drugs.
d. One of the functions of the smooth ER is detoxification.