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Question 1 2.5 / 2.5 point Question 2 2.5 / 2.5 point Question 3 2.5 / 2.5 point Question 4 2.5 / 2.5 point

Quiz Submissions - Exam 1- Chapters 1-6 Attempt Score:100 / 100 - 100

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Written: Aug 28, 2022 12:01 AM - Aug 28, 2022 1:24 AM

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Your quiz has been submitted successfully. If an integrin protein is mutated what cell function might be affected? communication between cytoskeleton and proteglycan fluidity of phospholipids cellular motility cytoplasmic communication See Q

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You and your roommate are grocery shopping. “I don’t get it,” she says. “My doctor said I should buy this special milk because I don’t digest it well. But this brand says ‘lactose-free’ and this brand says ‘lactase added’ – which do I want?” You reply: “The is a sugar in milk that you have trouble digesting, and is an enzyme that will digest it for you. lactase, lactose lactose,lactase See Q # 2 feedback What is the first step in Na+-K+ pump? The carrier protein has a reduced affinity for Na+ shape change increases the carrier's affinity for K+ ions Carrier protein binds to 3 Na+ ATP is hydrolyzed by a protein carrier Phosphate group is removed and K+ attach See Q # 3 feedback

What examples describe the second law of thermodynamics? Select all that apply.

Question 5 2.5 / 2.5 point Question 6 2.5 / 2.5 point Question 7 2.5 / 2.5 point Question 8 2.5 / 2.5 point A penny will fall when you pick it up and let it drop. A frying pan is on a hot stove. When removed it will cool. Ice cubes will melt in a warm room. Polar residues tend to bind to water in the cytoplasm as well as to each other. The water and polar residues cannot bind to the hydrophobic ones, so in th plasmodesmata, rough ER gap, smooth ER orange juice baking soda Donuts nutrients are used to help you exercise. In biological macromolecules like proteins, the hydrophobic residues tend to clump together in the interior of the folded structure. What is the best explanation for why this occurs? Hydrophobic residues bind each other, while polar residues cannot bind each other. Therefore the hydrophobic ones end up stuck to each other in the core of the protein. Protein folding machinery interprets the amino acid code to pack hydrophobic residues into the center of proteins. This process must be important, because the cell expends large amounts of ATP to precisely coordinate protein folding. Hydrophobic residues bind to each other in specific ways. For instance, Ala forms di-methyl bonds, and phenylalanine binds isoleucine. This creates a tightly bound hydrophobic inner core. 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? desmosomes, smooth ER tight, rough ER See Q # 6 feedback 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? urine black coffee lemons See Q # 7 feedback are used for energy storage.

Question 9 2.5 / 2.5 point Question 10 2.5 / 2.5 point Question 11 2.5 / 2.5 point Question 12 2.5 / 2.5 point Phospholipids Waxes Steroids Triglycerides Cholesterol See Q # 8 feedback When the solute concentration in solution 1 is lower than the solute concentration in solution 2, solution 2 is isotonic hypotonic hypertonic See Q # 9 feedback Noncompetitive inhibition occurs when a substance binds at the activity site a substance binds on a site away from the active site denaturing an enzyme increasing the activity of an enzyme See Q # 10 feedback How does the sodium-potassium pump make the interior of the cell negatively charged? by expelling anions by pulling in anions by expelling more cations than are taken in by taking in and expelling an equal number of cations See Q # 11 feedback If two solutions are different, the one will the higher concentration of solutes is isotonic hypertonic hypotonic

Question 13 2.5 / 2.5 point

Question 14 2.5 / 2.5 point Question 15 2.5 / 2.5 point Question 16 2.5 / 2.5 point Question 17 2.5 / 2.5 point A protein that unfolds or is incorrectly folded can use chaperones to correct the structure. when some proteins are denatured, with return of the normal environmental conditions they might refold. If sodium does not move down its gradient in the co-transport pump, what would be the outcome? Sugar would not be affected Sugar would not be able to move down the gradient Sugar would not be able to move up the gradient See Q # 13 feedback Researchers are working to develop biofuels to free us from dependence on fossil fuels. Based on what you know about cellulose, what do you predict are the major advantage and disadvantage of using cellulose-rich plant material as biofuel? There is not much energy in the glycosidic bonds of cellulose, but at least there is a lot of it. There is not much energy in the peptide bonds of cellulose, but at least it is very easy to break down The breakdown of cellulose into fructose is an endergonic reaction, but an enzyme can reverse the equilibrium. Cellulose is very difficult to break down into glucose, but it contains a lot of energy. See Q # 14 feedback The R group interactions, β-pleated sheets and α-helix structure can be denatured, but what interaction relevant to structure cannot be denatured? disulfide bridge ionic bonds hydrogen bonds peptide bonds hydrophobic interactions See Q # 15 feedback Indicate the statements that support the relationship between protein and structure. A proteins final shape is determined by the secondary structure. pH, temperature and agitation can denature proteins rendering them active. A disease may occur if proteins do not fold correctly. See Q # 16 feedback

In a chocolate bar with nuts and caramel, there are 12 grams of fat, 33 grams of carbohydrates and 4 grams of protein. What percentage of calories comes from fat?

Question 18 2.5 / 2.5 point Question 19 2.5 / 2.5 point Question 20 2.5 / 2.5 point Question 21 2.5 / 2.5 point

6.5%

19%

53%

See Q # 17 feedback prevent material from moving in or out of the brain's capillaries Desmosomes Plasmodesmatas Gap junctions Tight junctions See Q # 18 feedback Membrane proteins are able to cross because sections are composed of nonpolar phosphate regions hydrophobic amino acids hydrophilic phosphate regions polar amino acids hydrophilic amino acids. See Q # 19 feedback Larger cells function less effectively because as they increase in size, the surface area to volume ratio. stays the same increases decreases See Q # 20 feedback According to the 2 nd^ law of thermodynamics, energy cannot be created or destroyed energy transfers decrease entropy energy transfer increases the disorder of a system energy transfer creates an ordered system

Question 22 2.5 / 2.5 point Question 23 2.5 / 2.5 point Question 24 2.5 / 2.5 point Question 25 2.5 / 2.5 point 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 See Q # 21 feedback What are actin filaments? Darkened areas in the nucleus of a cell. Interconnected membranous sacs of a cell. Modified plasma membranes of a cell. Cytoskeletal structures of a cell. See Q # 22 feedback 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. 2 cell nucleus 5 human eyeball 3 DNA molecule (10bp) 1 Carbon atom 6 skin cell 4 human being 1. 0.1 nm

2. 1 μm 3. 1nm 4. 1m 5. 1cm 6. 10μm See Q # 23 feedback 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? He thought you would have to be lucky to notice a chance event. He thought that chance is the main determinant of who is successful in science, so all you can do is hope you get lucky. He thought that chance events are only useful if someone is intelligent enough to understand what happened. The shape of the cell is predominantly maintained by the plasma membrane cytoskeleton cytoplasm

endomembrane system

Question 26 2.5 / 2.5 point Question 27 2.5 / 2.5 point Question 28 2.5 / 2.5 point Question 29 2.5 / 2.5 point Question 30 2.5 / 2.5 point False True gated light energy in chemical bonds sound concentration gradients Phospholipids are naturally attracted to each other, forcing phosphate heads to face the aqueous areas. The fatty acid tails are forced together away from the water, and water can create hydrogen bonds with the phosphate heads. See Q # 25 feedback Baking soda can be swallowed to combine with excess hydrogen ions. Baking soda acts as a buffer. 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. ungated passive See Q # 27 feedback What is an example of potential energy? Select all that apply. heat When phospholipids are placed in water, why does a bilayer form? The polar tails will be attracted to the water and the nonpolar heads will be attracted to each other. Lipids are hydrophilic and will from hydrogen bonds with the water, forcing the hydrophobic heads towards the middle of the bilayer. See Q # 29 feedback 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

Question 31 2.5 / 2.5 point Question 32 2.5 / 2.5 point Question 33 2.5 / 2.5 point "Yes, anything we've learned about how Earth cells work is unlikely to be the same if evolution ran independently." "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 r phospholipid heads high energy Glycoproteins Phospholipids membranes might be inside out, with the polar heads on the inside and the tails on the outside!” What is your response? "Well that happens in specialized cells on Earth too. For instance, adipocytes have these inside-out membranes." "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." See Q # 30 feedback 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? phospholipid tails intrinsic membrane proteins cholesterol See Q # 31 feedback 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 low energy hydrogen electrostatic Which of the following form the foundation of plasma membranes? Glycolipids Fatty acids

Proteins

Question 34 2.5 / 2.5 point Question 35 2.5 / 2.5 point Question 36 2.5 / 2.5 point Question 37 2.5 / 2.5 point Question 38 2.5 / 2.5 point each protein is encoded by a distinct gene variation in tertiary structure variations in which amino acids are used See Q # 33 feedback An atom with an atomic mass of 89 and an atomic number of 39 has how many neutrons? 128 2 50 59 C 6 H 12 O 6 + 6O 2 → 6H 2 O + 6CO 2 is an example of. catabolism anabolism synthesis See Q # 35 feedback What factors allow a pool of 20 amino acids to produce thousands of unique proteins? (Select the 3 that apply.) variation in length of amino acid backbone variations in glycosidic linkage variations in the type of peptide bond How can ice float? the covalent bonds expand, decreasing density the hydrogen bonds expand, decreasing density the covalent bonds collapse, increasing density the hydrogen bonds collapse, increasing density See Q # 37 feedback 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.

Question 39 2.5 / 2.5 point Question 40 2.5 / 2.5 point They bind to receptors on the outside of the membrane, which then activate an intracellular signaling cascade. They are phagocytosed, degraded, and then released into the cell. They diffuse directly through the plasma membrane and into the cell. They make the membrane so fluid that small pores appear, allowing them to pass through. See Q # 38 feedback When the solute concentration in solution 1 is lower than the solute concentration in solution 2, solution 2 is isotonic hypotonic hypertonic See Q # 39 feedback Enzymes are catalysts in reactions. What statements describe functions of enzymes? Select all that apply. Enzymes are specific in their actions. Once an enzyme binds to a substrate, it cannot be used again. Enzymes lower the energy of activation needed for a reaction Enzymes change the amount of free energy produced Enzyme activity can be affected by temperature. See Q # 40 feedback