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Question 38 of 48

The equation below represents a(n)____________________.

2NO2   N2O4

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Question 48 of 48

Question 1 of 48

3.75 Points What factors allow a pool of 20 amino acids to produce thousands of unique proteins? (Select all that apply.) A. variation in length of amino acid backbone B. each protein is encoded by a distinct gene C. variation in tertiary structure D. variations in which amino acids are used E. variations in glycosidic linkage F. variations in the type of peptide bond
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Question 2 of 48

3.75 Points Organisms must use macromolecules that have properties to match their functional requirements. In the list below, choose the appropriate macromolecule whose properties meet the requirement. A. RNA B. DNA C. cellulose D. glycogen E. starch 1. Requirement:
Strong cell walls

Properties:
Linear polymer rigid and strong 2. Requirement
Stable storage of information

Properties:
4 base pairs, not easily hydrolyzed 3. Requirement:
Energy storage for seeds
Properties:
Energy-rich polysaccharides 4. Requirement:
Short-term energy storage (animals)
Properties:
Energy-rich polysaccharide 5. Requirement:
Transient transmission of information
Properties:
4 base pairs, easily hydrolyzed
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Question 3 of 48

3.75 Points To break chemical bonds to start a chemical reaction, ___________ energy is needed. A.kinetic B.potential C.activation D.free Reset Selection

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Question 4 of 48

3.75 Points Estrogen and testosterone are structurally related to cholesterol. Based on what you have learned about cholesterol, predict how these steroid hormones signal to the cell. A.They make the membrane so fluid that small pores appear, allowing them to pass through. B.They bind to receptors on the outside of the membrane, which then activate an intracellular signaling cascade. C.They are phagocytosed, degraded, and then released into the cell. D.They diffuse directly through the plasma membrane and into the cell. Reset Selection

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Question 5 of 48

3.75 Points Larger cells function less effectively because as they increase in size, the surface area to volume ratio ______________. A.stays the same B.increases C.decreases Reset Selection

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Question 6 of 48

3.75 Points What components are or can be present in cellular passive transport? A. phospholipids B. ATP C. concentration gradient D. carrier proteins E. amphiphilic molecules

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Question 7 of 48

3.75 Points Consider this hypothesis:
People who drink a lot of alcohol exhibit amoral behavior.
What is wrong with this hypothesis? (Select all that apply.) A. “A lot of alcohol” is not clearly defined. B.
Experiments cannot be conducted with people for ethical reasons. C. Human behavior is too complex to be studied scientifically. D. “Amoral behavior” is not clearly defined. E. The answer is obvious, so it cannot be falsified.
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Question 8 of 48

3.75 Points Cholera kills over 100,000 people each year worldwide due to diarrhea. The cholera toxin opens the CFTR chloride channel in the intestines, so that sufferers lose chloride, sodium and massive amounts of water.
On the other hand, the same CFTR channel is mutated in cystic fibrosis patients. With activity too LOW, they lack chloride flow and mucus builds up in the lungs.
This illustrates the importance of precise control of channel opening, known as
____________regulation. A.gated B.ungated C.passive Reset Selection

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Question 9 of 48

3.75 Points The cell theory states A.all cells are the smallest living things, all organisms are composed of one or more cells and all cells arise spontaneously B.all organisms are composed of multiple cells, all cells arise spontaneously and all cells require nutrients C.all organisms are composed of one or more cells, all cells are the smallest living things and all cells arise from other cells D.all cells will contain DNA, all cells are the smallest living things that can divide and all organisms are composed of cells Reset Selection

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Question 10 of 48

3.75 Points Plants, fungi and bacteria all have what similarity? A.central vacuole B.centrioles C.centrosomes D.cell wall E.mitochondria Reset Selection

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Question 11 of 48

3.75 Points What statement(s) describes a concentration gradient? A. Red blood cells cytoplasm contains a 0.9% salt solution. The extracellular fluid is 1.0%. B. The temperature inside the car is 39 degrees Celsius and the temperature outside the care is 39 degree Celsius. C. Oxygen in blood plasma is .31 per 100 ml. Oxygen carried with hemoglobin is .69 per 100 ml. D. Extracellular fluid contains 13.5 mmol of calcium, and 9 mmol of calcium is in the plasma.
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Question 12 of 48

3.75 Points NASA’s Kepler mission found evidence of several potentially habitable exoplanets, raising the possibility that life may have evolved independently outside of our solar system. If NASA found a novel lifeform, we would expect it to use energy molecules based on similar principles as lifeforms on Earth.
The organism would likely use molecules with
_____________ bonds. It might use two separate molecules, one serving as a rapidly utilizable energy currency and another molecule serving as long-term energy storage A.high energy B.low energy C.hydrogen D.electrostatic Reset Selection

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Question 13 of 48

3.75 Points How are the membrane components oriented? A.The hydrophobic heads are oriented towards the outside of the cell and the hydrophilic tails are oriented towards the inside of the cell. B.The hydrophilic heads are oriented towards the outside and the inside of the cell and the hydrophobic tails are oriented towards each other. C.The hydrophobic heads are oriented towards each other and the hydrophilic tails are oriented towards the outside and inside of the cell. D.The hydrophobic heads are oriented towards the inside of the cell and the hydrophilic tails are oriented towards the outside of the cell.
Reset Selection

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Question 14 of 48

3.75 Points According to the 2nd law of thermodynamics, A.energy cannot be created or destroyed B.energy transfer increases the disorder of a system C.energy transfer creates an ordered system D.energy transfers decrease entropy Reset Selection

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Question 15 of 48

3.75 Points Before the battery in the car is jumped, the individuals notice the hook-ups on the battery are corroded by acid. What substance can be used to clean the acid? A.orange juice B.baking soda C.urine D.black coffee E.lemons Reset Selection

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Question 16 of 48

3.75 Points Baking soda can be swallowed to combine with excess hydrogen ions. Baking soda acts as a buffer. True False Reset Selection

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Question 17 of 48

3.75 Points The R group interactions, -pleated sheets and -helix structure can be denatured, but what interaction relevant to structure cannot be denatured? A.peptide bonds B.hydrophobic interactions C.ionic bonds D.disulfide bridge E.hydrogen bonds Reset Selection

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Question 18 of 48

3.75 Points What protein is matched with its function? A.aquaporins – move water through the membrane by active transport B.carrier protein – nonspecific and will allow material to pass directly through C.channel protein – allow passage of material through the hydrophilic pore D.transport proteins – allow passage of material with the aid of ATP
Reset Selection

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Question 19 of 48

3.75 Points At a meal, you are served a hamburger with cheese, onions, and beef on a bun. What ingredients represent the most carbohydrates? Select all that apply. A. bun B. onion C. beef D. cheese
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Question 20 of 48

3.75 Points An atom with an atomic mass of 89 and an atomic number of 39 has how many
neutrons? A.128 B.2 C.50 D.59 Reset Selection

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Question 21 of 48

3.75 Points The NASA Mars rover has found evidence of water on Mars. This opens the possibility that life may have existed on another planet, perhaps evolving completely independently.
“Just think!” says your friend, “Extraterrestrial cells might be totally different than Earth cells. For example, the plasma membranes might be inside out, with the polar heads on the inside and the tails on the outside!”
What is your response? A.“That seems unlikely, since if a cell is in a watery environment, and has a watery cytoplasm, the polar head groups will still be most stable on the outside rather than pushed together.” B.“Yes, anything we’ve learned about how Earth cells work is unlikely to be the same if evolution ran independently.” C.“Since the gravity is much lower on Mars, that reduces the constraints on cell size and they are likely to be much bigger – but still with the charged heads on the outside.” D.“Well that happens in specialized cells on Earth too. For instance, adipocytes have these inside-out membranes.” Reset Selection

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Question 22 of 48

3.75 Points NASA has discovered a lifeform on another planet! They have called you to help them identify what kind of organism it is. Which features suggest that the lifeform is eukaryotic rather than prokaryotic? (Select all that apply.) A. cell wall B. Golgi apparatus C. nucleoid D. linear chromosomes E. mitochondria F. nucleus G. cell membrane H. membrane-bound organelles I. plasmids J. circular DNA
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Question 23 of 48

3.75 Points What are actin filaments? A.Modified plasma membranes of a cell. B.Darkened areas in the nucleus of a cell. C.Interconnected membranous sacs of a cell. D.Cytoskeletal structures of a cell. Reset Selection

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Question 24 of 48

3.75 Points What is the function of cholesterol in plasma membranes? A.regulates fluidity B.regulates pH C.allows ions to pass D.promotes artherosclerosis Reset Selection

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Question 25 of 48

3.75 Points The impermeability of cell plasma membranes is a major barrier to using drugs to kill tumor cells or affect cells transgenically. CPPs are peptides that were discovered to have the ability to transport themselves (and even attached cargo) into cells. How they get into cells is still a mystery, but CPPs all have multiple positively charged groups. Which of the following membrane components are they most likely to be interacting with? A.phospholipid heads B.intrinsic membrane proteins C.phospholipid tails D.cholesterol Reset Selection

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Question 26 of 48

3.75 Points You are designing a museum exhibit to teach people about cells. In the entrance to the exhibit, visitors riding a moving walkway under flashing lights will gradually “shrink” down in size. To create this illusion, visitors will pass giant models of various biological parts, accompanied by scale bars.
Match each model to the appropriate scale bar to go with it. A. 1nm B. 1 m C. 10m D. 1cm E. 0.1 nm F. 1m 1. Carbon atom 2. cell nucleus 3. DNA molecule (10bp) 4. human being 5. human eyeball 6. skin cell
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Question 27 of 48

3.75 Points A tarantula has eight legs, an arachnid in the order Araneae. A grass spider has eight legs, an arachnid in the order Araneaa. A mouse spider has eight legs, an arachnid in the order Araneae. There is a pattern. All organisms in this order have eight legs. This is
reasoning
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Question 28 of 48

3.75 Points Membrane proteins are able to cross because sections are composed of A.nonpolar phosphate regions B.hydrophobic amino acids C.polar amino acids D.hydrophilic phosphate regions E.hydrophilic amino acids. Reset Selection

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Question 29 of 48

3.75 Points Indicate the statements that support the relationship between protein and structure. A. A protein that unfolds or is incorrectly folded can use chaperones to correct the structure. B. when some proteins are denatured, with return of the normal environmental conditions they might refold. C. A proteins final shape is determined by the secondary structure. D. pH, temperature and agitation can denature proteins rendering them active. E. A disease may occur if proteins do not fold correctly.
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Question 30 of 48

3.75 Points Which statements describe sodium atoms? Select all that apply. A. outer energy level is stable B. has 2 electrons in the first energy level C. forms cations D. contains 1 valence electron E. easily forms covalent bonds F. closest to the left side of the periodic table G. can lose one electron easily
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Question 31 of 48

3.75 Points Noncompetitive inhibition occurs when A.a substance binds at the activity site B.a substance binds on a site away from the active site C.denaturing an enzyme D.increasing the activity of an enzyme Reset Selection

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Question 32 of 48

3.75 Points When the solute concentration in solution 1 is lower than the solute concentration in solution 2, solution 2 is A.isotonic B.hypotonic C.hypertonic Reset Selection

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Question 33 of 48

3.75 Points When phospholipids are placed in water, why does a bilayer form? A.The fatty acid tails are forced together away from the water, and water can create hydrogen bonds with the phosphate heads. B.The polar tails will be attracted to the water and the nonpolar heads will be attracted to each other. C.Phospholipids are naturally attracted to each other, forcing phosphate heads to face the aqueous areas. D.Lipids are hydrophilic and will from hydrogen bonds with the water, forcing the hydrophobic heads towards the middle of the bilayer. Reset Selection

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Question 34 of 48

3.75 Points If sodium does not move down its gradient in the co-transport pump, what would be the outcome? A.Sugar would not be affected B.Sugar would not be able to move down the gradient C.Sugar would not be able to move up the gradient Reset Selection

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Question 35 of 48

3.75 Points Enzymes are catalysts in reactions. What statements describe functions of enzymes? Select all that apply. A. Enzymes are specific in their actions. B. Once an enzyme binds to a substrate, it cannot be used again. C. Enzymes lower the energy of activation needed for a reaction D. Enzymes change the amount of free energy produced E. Enzyme activity can be affected by temperature.
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Question 36 of 48

3.75 Points Rosenberg, a chemist, was observing the effects of an electric field on bacterial growth. He observed that bacteria stopped dividing when in an electric field. This research led to the anti-cancer drug cisplatin, a platinum containing compound. Rosenberg’s discovery was an example of science.
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Question 37 of 48

3.75 Points Cardiac muscle requires junctions that allow electrical signals through. Cardiac muscle also relies on calcium to contract. What junction is involved and what organelle stores calcium? A.desmosomes, smooth ER B.plasmodesmata, rough ER C.gap, smooth ER D.tight, rough ER Reset Selection

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Question 38 of 48

3.75 Points

The equation below represents a(n)____________________.

2NO2   N2O4

A.irreversible reaction B.reversible reaction C.reactant D.product E.enzymatic reaction Reset Selection

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Question 39 of 48

3.75 Points The microbiologist Louis Pasteur invented pasteurization, created vaccines for anthrax and rabies, and helped explain the germ theory of disease. He is often quoted as saying, “Chance favors the prepared mind.” A more accurate translation from the French, however, is “Where observation is concerned, chance favors only the prepared mind.” What can you conclude about Pasteur’s attitude about the role of chance in scientific discovery? A.He thought that chance is the main determinant of who is successful in science, so all you can do is hope you get lucky. B.He thought you would have to be lucky to notice a chance event. C.He thought that observation of something unique doesn’t do any good if the scientist is not prepared to interpret and follow up on the chance discovery, due to a habit of studious work. D.He thought that chance events are only useful if someone is intelligent enough to understand what happened. Reset Selection

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Question 40 of 48

3.75 Points The evil arch-villain Dr. Black Thumb has created a new plant pathogen. The microbe has an enzyme allowing it to quickly convert 1-4 glycosidic linkages to 1-4 glycosidic linkages in a whole field of plants. If Dr. Black Thumb’s plan is not thwarted, crop harvests could be ruined due to A.amylose and amylopectin becoming hard and inedible. B.
plants flopping over. C.polysaccharides converting into monosaccharides. D.plant starches becoming rigid and popping cell membranes. Reset Selection

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Question 41 of 48

3.75 Points What is an example of potential energy? Select all that apply. A. light B. concentration gradients C. energy in chemical bonds D. heat E. sound
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Question 42 of 48

3.75 Points The fluid mosaic model describes membranes as fluid due to A.phospholipids sporadically placed throughout the membrane B.the membrane is mostly composed of water C.the proteins and the phospholipids can move laterally throughout the membrane D.higher amounts of cholesterol E.higher amounts of cholesterol Reset Selection

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Question 43 of 48

3.75 Points Molecules move from a high to low concentration in A.isotonic solutions B.hypotonic solutions C.hypertonic solutions D.diffusion E.osmosis Reset Selection

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Question 44 of 48

3.75 Points When viewing the shape of a human cheek cell, what microscope would most likely be used? A.light B.dissecting C.transmission electron D.scanning electron Reset Selection

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Question 45 of 48

3.75 Points The building blocks of nucleic acids are A.peptides. B.nucleotides. C.nitrogenous bases. D.sugars. Reset Selection

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Question 46 of 48

3.75 Points Carbon-12, Carbon-13, and Carbon-14 are examples of
A.isomers B.molecules C.ions D.isotopes E.enantiomers Reset Selection

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Question 47 of 48

3.75 Points Which molecule(s) would dissolve in water based on polarity? Select all that apply. A. CH4 B. C2H6 C. C6H6 D. CH3CH2 CH2 CH2 CH2 CH2OH E. C5H10O5
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Question 48 of 48

3.75 Points The shape of the cell is predominantly maintained by the A.plasma membrane B.cytoskeleton C.cytoplasm D.endomembrane system Reset Selection

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Explanation / Answer

1)

Factors allow a pool of 20 amino acids to produce thousands of unique proteins is variation in length of amino acid backbone and variations in which amino acids are used. Thus, the correct options are (A) and (D).

2)

A. RNA- (5)

B. DNA- (2)

C. cellulose- (1)

D. glycogen- (4)

E. starch- (3)

3)

To break chemical bonds to start a chemical reaction, activation energy is needed.

4)

D. They diffuse directly through the plasma membrane and into the cell.

5)

B. increases

6)

A, C, and D.

7)

C. Human behavior is too complex to be studied scientifically.

8)

A. gated

9)

The cell theory states (C) all organisms are composed of one or more cells, all cells are the smallest living things and all cells arise from other cells.

10)

Plants, fungi and bacteria all have what similarity- D. cell wall

11)

A and C.

12)

The organism would likely use molecules with electrostatic bonds. It might use two separate molecules, one serving as a rapidly utilizable energy currency and another molecule serving as long-term energy storage

13)

B. The hydrophilic heads are oriented towards the outside and the inside of the cell and the hydrophobic tails are oriented towards each other.

14)

B. energy transfer increases the disorder of a system

15)

B. baking soda can be used to clean the acid.

16)

True

45)

B

46)

D

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