AP Bio Exam Review Set

If a cells pressure potential = 3 and its solute potential = -4.5 bars, what is the resulting water potential? (1 pt)

-1.5 bars

List the four groups of neurotransmitters below (1 pt)

Amino acids, gases, neuropeptides, and biogenic amines

The myelin sheath plays an important role in neuron structure and function. However, when the myelin sheath is missing or not fully intact, there are consequences. There are many conditions that cause demyelination of neurons, some are autoimmune disorders, such as multiple schlerosis, and others are hereditary. The symptoms of these conditions vary, but often include speech impairment and difficulty coordinating movement. Which of the following correctly connects the symptoms of demyelination with the process of nerve impulse transmission? A)Demyelination prevents the formation of an action potential in sensory neurons that transmit signals from the environment to the central nervous system. B)Demyelination slows nerve impulse transmission. C)Demyelination prevents the uptake of neurotransmitters needed to propagate a message to the next neuron. D)Demyelination targets the central nervous system.

B)

What determines the secondary structure of a protein?

Beta pleated sheet or alpha helix. Determined by the hydrogen bonds formed in the peptide backbone.

BONUS: Explain how the botulism toxin leads to paralysis. Be sure to include details about what neurotransmitter it mimics. (1 pt)

Botulism toxin mimics acetylcholine. Acetylcholine is the neurotransmitter that controls breathing, heart beat, muscle movements, etc. The botulism toxin causes paralysis because it mimics the acetylcholine but is unable to produce an action potential like the acetylcholine. Since the botulism toxin is unable to produce an action potential, that leaves the muscles being unable to move, the heart being unable to beat, and the lungs being unable to move. Essentially, the botulism toxin is able to go to the same places as the acetylcholine, but is unable to produce an action potential, which makes everything unable to work.

BONUS: Scientists in Australia wanted to know the relationship between sea urchins, limpets, and the distribution of seaweed. Both sea urchins and limpets are herbivores that graze on seaweed. What do the data shown in this figure indicate about the pattern and distribution of seaweeds? (Refer to chart on Ecology MC Test 2019) A)Both species influence seaweed distribution, but limpets have the primary effect. B)Seaweed distribution is determined by global sea temperatures, not predators. C)Sea urchins have the greatest influence on seaweed distribution. D)The influence on seaweed distribution is roughly equal in impact from both limpets and sea urchins.

C)Sea urchins have the greatest influence on seaweed distribution.

When an action potential arrives at the presynaptic membrane, depolarization occurs, opening voltage-gated channels. This allows an influx of Ca2+ ions that are needed to trigger the release of neurotransmitter into the synapse. If a calcium channel blocker, such as cadmium, is injected into the presynaptic cell, which explanation best describes cadmium's effect on the transmission of the impulse? (Refer to picture on Neuron Test) A)Elevated cadmium levels cause synaptic vesicles to fuse with the presynaptic membrane thus releasing their neurotransmitters into the synapse triggering an impulse. B)Blocking the voltage-gated channels causes the synaptic vesicles to release their neurotransmitters within the presynaptic cell thus reversing the direction of the impulse. C)Elevated levels of cadmium block the ligand-gated ion channels on the postsynaptic membrane that prevents neurotransmitters from binding. D)Elevated cadmium levels prevent the influx of Ca2+ ions into the presynaptic cell that prevents the release of neurotransmitters into the synapse.

D)

Explain the endosymbiont theory. What evidence supports this theory? Hypothesize how the evolutionary history of cells might have differed had endosymbiosis not occurred. (3pts)

Endosymbiont theory is the theory that organelles found in cells were once their own cell, but were at some point absorbed into a larger host cell. For example, mitochondria at one point were their own cell rather than a piece of another, larger cell. The evidence to support this theory is that for one, organelles that were believed to be their own cell have their own DNA. This means that mitochondria, for example, can only make other mitochondria. No other organelle in the cell has the ability to make a mitochondria organelle. Another piece of evidence to support this theory is the double membrane that some organelles have. For example, mitochondria has its own membrane as well being enclosed in the plasma membrane that protects the cell. If endosymbiosis had not occurred, cells would be a lot less complex and a lot less able to perform specific functions. For example, it is crucial that liver cells have lots of peroxisomes to be able to detoxify the toxic things in the liver. If endosymbiosis had not occurred, liver cells may not be as capable of performing that specific function due to their lack of peroxisomes that are necessary to complete the task. Something to note: Organisms would be simple, or single celled and lack the sophistication of eukaryotic cells.

Acetylcholine is a neurotransmitter that can activate an action potential in a postsynaptic neuron (Fig 1 and 2). A researcher is investigating the effect of a particular neurotoxin that causes the amount of acetylcholine released from presynaptic neurons to increase.Describe the immediate effect of the neurotoxin on the number of action potentials in a postsynaptic neuron. Predict whether the maximum membrane potential of the postsynaptic neuron will increase, decrease or stay the same. Explain your reasoning. (3 pts) (Refer to picture on Neuron Test)

I believe that the maximum membrane potential of the postsynaptic neuron will increase. I believe this because since the neurotoxin is increasing the amount of acetylcholine that is being released from the presynaptic cell, the membrane potential will increase because there is more acetylcholine being released which will cause a higher number of action potentials in the post-synaptic cell. Thus, this increase of action potentials will cause a higher membrane potential. Something to note: would there be more or less action potentials? Why?would the depolarization on the axon increase, decrease or stay the same? Why?

The following ribose molecule contains how many asymmetric carbons? (Refer to picture on Biochemistry Test)

Idek but good luck

If the plant cell wall or the animal extracellular matrix were impermeable, what effect would this have on cell function? (2 pts)

If the plant cell wall or the animal extracellular matrix were impermeable, then it would be a lot harder for cells to communicate. For example, if the animal extracellular matrix was impermeable, then gap junctions could not exist. However, gap junctions are important to the communication between certain types of cells and without gap junctions those cells would have no means of communication or sharing of necessary resources.

Acetylcholine is a neurotransmitter that can activate an action potential in a postsynaptic neuron (Fig 1 and 2). A researcher is investigating the effect of a particular neurotoxin that causes the amount of acetylcholine released from presynaptic neurons to increase.The researcher proposes two models, A and B, for using acetylcholinesterase (AChE), an enzyme that degrades acetylcholine, to prevent the effect of the neurotoxin. In model A, AChE is added to the synapse. In model B, AChE is added to the cytoplasm of the postsynaptic cell. Predict the effectiveness of EACH proposed model. Provide reasoning to support your predictions. (4 pts) (Refer to picture on Neuron Test)

Model A, in which the enzyme is added to the synapse, would not be very effective. Since the synapse is essentially an open space between the dendrite of the presynaptic cell and the cell body of the postsynaptic cell, the enzyme will pretty much be able to diffuse and spread out as much as possible. I believe that since it can diffuse through the space outside of the cells, it will not stay in the synapse. Therefore, the enzyme will not be very effective if added to the synapse because the enzyme will diffuse too much and not be able to target very many acetylcholine molecules.Model B, in which the enzyme is added to the cytoplasm of the postsynaptic cell, would be much more effective. Since the enzyme is forced to stay embedded into the cytoplasm of the postsynaptic cell, it will likely have a greater chance of coming into contact with and being able to target molecules of acetylcholine. Therefore, I believe that adding the enzyme into the cytoplasm of the postsynaptic cell will be much more effective than adding the enzyme into the synapse between the two cells. Something to note: Model A will work better- why? Where is acetylcholine stored in post-synaptic cell?

A human pancreatic cell obtains O2- and necessary molecules such as glucose, amino acids and chlolesterol- from its environment, and it releases CO2 as a waste product. In response to hormonal signals, the cell secretes digestive enzymes. It also regulates its ion concentrations by exchange with its environment. Based on what you have lerned about the structure and function of cellular membanes, write a short essay to describe how such a cell accomplishes these interactions with its environment.

Obtaining small, uncharged particles such as O2 is not a hard job for the cell because the O2 is able to freely diffuse through the membrane and into the cell. However, since things such as glucose and amino acids are bigger and charged, it will not be as easy for the cell to obtain those resources from their surrounding environment. In order to obtain glucose, the cell carries out a process called phagocytosis, or "cell-eating", where the cell absorbs the food particle into the cell to begin breaking it down. To obtain things such as amino acids and cholesterol, the cell will likely use endocytosis, which is the taking in of resources from the cell's environment through the use of a vesicle. In order to get rid of CO2 as a waste product, the cell must use exocytosis. Exocytosis is the packaging of a waste product to send it outside of the cell. The cell also secretes digestive enzymes in response to a specific hormone signal. This response likely happens because of a phosphorylation cascade. So, when a specific hormone binds to a specific GPCR (G Protein Coupled Receptor), the GCPR will use GTP to activate a G Protein. Next, the G Protein will slide over to a specific enzyme in the cell and bind to it, turning it on. That enzyme will then convert ATP into a second messenger. The second messenger will then go to a protein kinase in the cell and activate it. The protein kinase will then take a phosphate group off of ATP and send that phosphate to the next protein kinase, starting a phosphorylation cascade. The cascade will then continue until the cell responds by secreting the digestive enzymes from the cell.

Which is the bigger one? Peroxisome or Lysosome?

Peroxisome.

What determines the tertiary structure of a protein?

The R-groups and the way that they interact and bond.

What determines the Quaternary structure of a protein?

The same bonds and interactions of the tertiary structure. This just makes the protein more 3D and stabilized.

What determines the primary structure of a protein?

The sequence of amino acids

Calculate the solute potential of a 0.3 M sucrose solution in an open beaker at 27 degrees Celcius. (1 pt)

The solute potential of this solution would be -7.479 bars.

Males afflicted with Kartagener's syndrome are sterile because of immotile sperm, and they tend to suffer from lung infections. This disorder has a genetic basis. Suggest what the underlying defect might be. (2 pts)

The underlying defect of Kartagener's syndrome is likely found in the microtubules that make up the flagella of cells. The flagella is what allows the sperm cell to move, so if the sperm cell is unable to move, the problem must be with the flagella. The flagella is made up of microtubules, so since the sperm is unable to move, there is likely something wrong with the structure of the microtubule which leaves the sperm cell immotile. If the sperm cell cannot move, then it cannot reach the ovum to fertilize it, which is why the male is considered sterile. Something to note: Male that have Kartagener's syndrome likely do not have properly functioning cilia and flagella. Sperm use flagella to move and there is cilia in lungs to help move mucus. There is probably something wrong with the synthesis of microtubules that make up cilia and flagella.

An unknown macromolecule material recovered from a cell is found to contain the elements C,H,O,P, and N. Discuss the match of this unknown macromolecule to all known classes of macromolecules. Your discussion should detail why the unknown does or does not seem to match with each macromolecule class. Include any additional information that might be needed to match the unknown to a known class. (4 pts)

The unknown macromolecule would not be a carbohydrate due to the presence of phosphorus and nitrogen in it. Since carbohydrates are made up solely of carbon, hydrogen, and oxygen, the unknown macromolecule can not be a carbohydrate. The unknown macromolecule can also not be a lipid due the presence of nitrogen within it. Lipids contain only carbon, hydrogen, and oxygen, and occasionally they will contain phosphorus as well. Since the unknown macromolecule has nitrogen in it as well, it can not be a lipid. The unknown macromolecule can also not be a protein due to the presence of phosphorus within it. Since proteins can only contain carbon, hydrogen, nitrogen, and sulfur, the presence of phosphorus makes it certain that the unknown macromolecule is not a protein. The unknown macromolecule is likely a nucleic acid because nucleic acids can contain carbon, hydrogen, oxygen, nitrogen, and phosphorus, just like this macromolecule has. Due to the fact that this macromolecule can not be a carbohydrate, lipid, or protein, it must be a nucleic acid. Plus, the macromolecule fits all the elements that a nucleic acid has.

If the cell above is placed in an open beaker of sugar water with a solute potential of -4.0 bars, in which direction will the net flow of water be? (1 pt) (refer to question 33 on Cell Transport Test)

The water will want to move out of the cell and into the surrounding solution of sugar water.

Which of the following examples describes a behavioral pattern that results from a proximate cause? a. A cockroach runs into a crack in the wall and avoids being stepped on. b. A goose squats and freezes motionless to escape a predator. c. A male sheep fights with another male because it helps to improve its social position. d. A cat kills a mouse to obtain nutrition. e. A female bird lays its eggs because the amount of daylight is decreasing slightly each day.

a. A cockroach runs into a crack in the wall and avoids being stepped on.

The behavior of most animals is influenced by the periods of daylight and darkness in the environment. Fiddler crabs' courtship behaviors are instead synchronized by the 29 1/2-day cycle of the moon. What is the adaptive significance of using lunar cues? a. By courting at the full and new moon, fiddler crabs link their reproduction to the times of the highest tides that disperse their larvae to safer, deeper waters. b. The algae that larval fiddler crabs consume for energy and metabolism bloom on a monthly cycle, so recently hatched larvae have plenty to eat during a crucial time of their lives. c. It takes about 29 days for a fiddler crab to reach sexual maturity. d. Egg maturation in fiddler crab females takes 29 1/2 days. e. The fiddler crab courtship ritual is highly visual, so individuals need the light of the full moon to be able to observe courtship displays.

a. By courting at the full and new moon, fiddler crabs link their reproduction to the times of the highest tides that disperse their larvae to safer, deeper waters.

Why isn't the mitochondrion classified as part of the endomembrane system? a. It is not derived from the endoplasmic reticulum or Golgi. b. It has a double membrane structure. c. It produces a special class of transport vesicles. d. It is not involved in protein synthesis.

a. It is not derived from the endoplasmic reticulum or Golgi.

Which of the following is true of steroid (testosterone) receptors? a. The receptor molecules may be soluble proteins in the cytoplasm. b. The receptor molecules are themselves lipids or glycolipids. c. The receptor molecules are transmembrane proteins with the ligand binding domain on the inside of the cell. d. The receptor molecules are transmembrane proteins with the ligand binding domain on the outside of the cell. e. The receptor molecules are peripheral proteins embedded in the interior layer of the plasma membrane.

a. The receptor molecules may be soluble proteins in the cytoplasm.

Which of the following would increase the electrochemical gradient across a membrane? a. a proton pump b. a sucrose-proton cotransporter c. a chloride channel d. a potassium channel

a. a proton pump

Which of the following molecules lacks amino acids? a. cholesterol b. antibodies c. spider silk d. hemoglobin e. insulin

a. cholesterol

Somatic motor neurons are used to transmit motor signals to muscles. For example, a somatic motor neuron carries a signal from your spinal cord to your biceps brachii so that you can flex your arm at the elbow. In this example, what is the correct sequence of neuronal structures that this signal would travel through in the motor neuron? a. dendrites, cell body, axon hillock, axon, synaptic terminals, biceps brachii b. dendrites, cell body, axon, axon hillock, synaptic terminals, biceps brachii c. synaptic terminals, dendrites, cell body, axon, axon hillock, biceps brachii d. axon, cell body, synaptic terminals, dendrites, axon hillock, biceps brachii

a. dendrites, cell body, axon hillock, axon, synaptic terminals, biceps brachii

The movement of the hydrophobic gas nitrous oxide (N2O) (laughing gas) into a cell is an example of a. diffusion through the lipid bilayer. b. osmosis through the lipid bilayer. c. active transport across the lipid bilayer. d. cotransport across the lipid bilayer. e. facilitated diffusion through the lipid bilayer.

a. diffusion through the lipid bilayer.

Which of the following are purines? a. guanine and adenine b. uracil and cytosine c. thymine and uracil d. adenine and thymine e. cytosine and guanine

a. guanine and adenine

Movement of vesicles within the cell depends on what cellular structures? a. microtubules and motor proteins b. actin filaments and microtubules c. centrioles and motor proteins d. actin filaments and motor proteins

a. microtubules and motor proteins

Most of the neurons in the peripheral nervous system that cause a reaction to a stimulus are a. motor neurons. b. interneurons. c. nerves. d. sensory neurons.

a. motor neurons.

Which of the following is an expected characteristic of K-selected populations? a. offspring with good chances of survival b. early parental reproduction c. a high intrinsic rate of increase d. small offspring

a. offspring with good chances of survival

Receptors for neurotransmitters are of primary functional importance in assuring one-way synaptic transmission because they are mostly found on the a. postsynaptic dendritic membrane. b. presynaptic membrane. c. axonal membrane. d. axon hillock.

a. postsynaptic dendritic membrane.

A cell with an abundance of free ribosomes is most likely a. producing primarily cytoplasmic proteins. b. enlarging its vacuole. c. producing primarily proteins for secretion. d. producing primarily cell wall or extracellular matrix components. e. producing primarily an abundance of new membranes.

a. producing primarily cytoplasmic proteins.

Extracellular matrix proteins are produced by ribosomes in which part of a eukaryotic cell? a. rough ER b. nuclear envelope c. lysosomes d. cytoplasm e. Golgi apparatus

a. rough ER

Which of the following correctly describes the pathway taken by a protein destined for secretion from an animal cell? a. rough ER → transport vesicle → Golgi → transport vesicle → plasma membrane b. plasma membrane → transport vesicle → Golgi → transport vesicle → rough ER c. rough ER → transport vesicle → Golgi → transport vesicle → lysosome → plasma membrane d. Golgi → rough ER → transport vesicle → plasma membrane e. rough ER → transport vesicle → lysosome → transport vesicle → plasma membrane

a. rough ER → transport vesicle → Golgi → transport vesicle → plasma membrane

What is the structure shown in Figure 3.10? (Refer to picture on Biochemistry Test) a. steroid molecule b. triacylglycerol molecule c. fatty acid molecule d. phospholipid molecule

a. steroid molecule

Interactions between the side chains (R groups) in a polypeptide are most important in stabilizing which of the following? a. tertiary structure b. quaternary structure c. secondary structure d. primary structure

a. tertiary structure

Which of the following graphs illustrates the population growth curve of single bacterium growing in a flask of ideal medium at optimum temperature over a 24-hour period? (Refer to chart on Ecology MC Test 2019) a. b. c. d.

b.

The solutions in the arms of a U-tube (Figure 5.3) are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same. Refer to the figure to answer the following questions.If you examine side A in the figure after three days, the concentrations of glucose and NaCl should be (refer to picture on Cell Transport Test) a. 0.4 M glucose, 0.45 M NaCl. b. 0.6 M glucose, 0.45 M NaCl. c. 0.8 M glucose, 0.5 M NaCl. d. 0.8 M glucose, 0.4 M NaCl. e. 0.6 M glucose, 0.5 M NaCl.

b. 0.6 M glucose, 0.45 M NaCl.

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? a. Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable. b. Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. c. Hydrolysis creates monomers, and dehydration reactions break down polymers. d. Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers. e. Dehydration reactions can occur only after hydrolysis.

b. Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.

Which of the following pairs of reproductive strategies is consistent with energetic trade-off and reproductive success? a. Some mammals will not reproduce when environmental resources are low so they can survive until conditions get better, and plants that produce many small seeds are likely found in stable environments. b. Female rabbits that suffer high predation rates may produce several litters per breeding season, and coconuts produce few fruits, but most survive when they encounter proper growing conditions. c. Species that have to broadcast to distant habitats tend to produce seeds with heavy protective seed coats, and animals that are caring parents produce fewer offspring with lower infant mortality. d. Pioneer species of plants produce many very small, highly airborne seeds, whereas large elephants that are very good parents produce many large offspring. e. A free-living insect lays thousands of eggs and provides no parental care, whereas a flowering plant takes good care of its thousands of seeds until they are ready to germinate.

b. Female rabbits that suffer high predation rates may produce several litters per breeding season, and coconuts produce few fruits, but most survive when they encounter proper growing conditions.

A population is correctly defined as having which of the following characteristics? I.inhabits the same general area II.belongs to the same species III.possesses a constant and uniform density and dispersion a. III only b. I and II only c. I only d. I, II, and III e. II and III only

b. I and II only

DNase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNase? a. Oxygen atoms would be removed from the deoxyribose sugars. b. The phosphodiester bonds between deoxyribose sugars would be broken. c. The bases would be separated from the deoxyribose sugars. d. The two strands of the double helix would separate.

b. The phosphodiester bonds between deoxyribose sugars would be broken.

Which of the following is a correct monomer/polymer pairing? a. amino acid/polysaccharide b. amino acid/polypeptide c. monosaccharide/polypeptide d. glycerol/triglyceride

b. amino acid/polypeptide

The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on a pH gradient across the membrane-more acidic outside the cell than inside the cell. Phosphate transport is an example of a. receptor-mediated endocytosis. b. cotransport. c. active transport. d. passive diffusion. e. facilitated diffusion.

b. cotransport.

The primary function of phosphatases in signal transduction is to a. amplify signal transduction so it activates multiple relay molecules. b. inactivate protein kinases to turn off signal transduction. c. transfer a phosphate group from a kinase to the next relay molecule in a series. d. amplify the second messenger cAMP.

b. inactivate protein kinases to turn off signal transduction.

Based on the figure below, which of these experimental treatments would increase the rate of sucrose transport into a plant cell? (Refer to picture on Cell Transport Test) a. decreasing extracellular sucrose concentration b. increasing extracellular H+ concentration c. increasing H+ concentration inside of the cell d. adding a substance that makes the membrane more permeable to hydrogen ions

b. increasing extracellular H+ concentration

Which of the following enzymes adds a phosphate group to target proteins? a. adenylyl cyclase b. kinase c. phosphatase d. glycogen phosphorylase

b. kinase

Which structure-function pair is mismatched? a. nucleolus; production of ribosomal subunits b. microtubule; muscle contraction c. ribosome; protein synthesis d. Golgi; protein trafficking

b. microtubule; muscle contraction

Which structures are involved in cell movement? a. cytoplasm and ribosomes b. microtubules and microfilaments c. nucleolus and nucleus d. chromosomes

b. microtubules and microfilaments

In an animal cell, DNA may be found a. only in the nucleus. b. only in the nucleus and mitochondria. c. only in the nucleus and rough ER. d. in the nucleus, mitochondria, and rough ER.

b. only in the nucleus and mitochondria.

The secretion of a signal molecule by a cell into the local environment, followed by a response by a number of cells in the immediate vicinity, is an example of a. extracellular matrix signaling. b. paracrine signaling. c. endocrine signaling. d. synaptic signaling. e. hormonal signaling.

b. paracrine signaling.

Which of the following tend to lack hydrophobic regions on their surface? a. integral proteins b. peripheral proteins c. cholesterol d. integrins e. transmembrane proteins

b. peripheral proteins

The two molecules shown in the figure above are best described as (refer to second picture on Biochemistry Test) a. chain length isomers. b. structural isomers. c. cis-trans isomers. d. optical isomers. e. enantiomers.

b. structural isomers.

Where are neurotransmitter receptors located? a. synaptic vesicle membranes b. the postsynaptic membrane c. the nuclear membrane d. the nodes of Ranvier

b. the postsynaptic membrane

What is the fitness benefit of polygamy in birds that rear young that are precocious (develop and mature rapidly)? a. Females don't have to spend time rearing young and can mate and rear additional broods during a breeding season. b. Females don't have to decide on one mate and can copulate with as many males as they deem worthy to share their genes with in reproduction. c. Fit males don't have to help feed and rear young and can spend this time seeking out and mating with many females. d. Both males and females spend little time with courtship and brood-rearing and don't tax their own physiology, so they can breed again in subsequent breeding seasons. e. Females will copulate with many males to ensure that all of their eggs are fertilized.

c. Fit males don't have to help feed and rear young and can spend this time seeking out and mating with many females.

Following activation of a receptor, which sequence below represents the correct order in which components will be involved in a signaling pathway that utilizes the second messenger cAMP? a. adenyl cyclase → cAMP → G protein → protein kinase b. protein kinase → G protein → adenyl cyclase → cAMP c. G protein → adenyl cyclase → cAMP → protein kinase d. cAMP → adenyl cyclase → protein kinase → G protein e. G protein → cAMP → adenyl cyclase → protein kinase

c. G protein → adenyl cyclase → cAMP → protein kinase

The R group or side chain of the amino acid serine is -CH2-OH. The R group or side chain of the amino acid leucine is -CH2-CH-(CH3)2. Where would you expect to find these amino acids in a globular protein in aqueous solution? a. Both serine and leucine would be in the interior and on the exterior of the globular protein. b. Both serine and leucine would be in the interior of the globular protein. c. Leucine would be in the interior, and serine would be on the exterior of the globular protein. d. Serine would be in the interior, and leucine would be on the exterior of the globular protein. e. Both serine and leucine would be on the exterior of the globular protein.

c. Leucine would be in the interior, and serine would be on the exterior of the globular protein.

Changing the amino acid lysine to valine in the figure shown above would alter which of the following? (USE THE CHART PROVIDED TO HELP) (Refer to chart on Biochemistry Test) a. alter the primary structure of the protein, but not its tertiary structure or function. b. no change in the biological activity or function of the protein. c. alter both the primary structure and the tertiary structure of the protein, while also affecting its biological activity. d. only alter the primary structure of the protein. e. cause only a change in the tertiary structure of the protein

c. alter both the primary structure and the tertiary structure of the protein, while also affecting its biological activity.

Changing the amino acid lysine to which of the following amino acids would cause the least amount of change to the shape of the protein? (Refer to chart on Biochemistry Test) a. tyrosine b. tryptophan c. arginine d. proline e. glutamic acid

c. arginine

Functionally, which cellular location is the neuron's "decision-making site" as to whether or not an action potential will be initiated? a. axonal membrane b. dendritic membrane c. axon hillock d. presynaptic membrane

c. axon hillock

Which two functional groups are always found in amino acids? a. hydroxyl and carboxyl b. ketone and amino c. carboxyl and amino d. carbonyl and amino

c. carboxyl and amino

The two molecules shown in the figure above are best described as (refer to first picture of these on Biochemistry Test) a. enantiomers. b. nonisotopic isomers. c. cis-trans isomers. d. radioactive isotopes. e. structural isomers.

c. cis-trans isomers.

The evolution of eukaryotic cells most likely involved a. endosymbiosis of an oxygen-using photosynthetic bacterium in a larger host cell-the endosymbiont evolved into mitochondria. b. endosymbiosis of an oxygen-using scavenger bacterium in a larger host cell-the endosymbiont evolved into lysosomes. c. endosymbiosis of an oxygen-using bacterium in a larger host cell-the endosymbiont evolved into mitochondria. d. evolution of an endomembrane system and subsequent evolution of mitochondria from a portion of the Golgi.

c. endosymbiosis of an oxygen-using bacterium in a larger host cell-the endosymbiont evolved into mitochondria.

Which of the following describes a Type I survivorship curve? a. a constant death rate over the organism's life span b. dropping sharply at the start, reflecting very high death rates for the young, then flattening out as death rates decline for those few that survive c. flat at the start, reflecting low death rates during early and middle life, then dropping steeply as death rates increase among older age groups d. flat at the start, reflecting low death rates during early and middle life, then rising steeply as death rates decrease among older age groups

c. flat at the start, reflecting low death rates during early and middle life, then dropping steeply as death rates increase among older age groups

Humans can digest starch but not cellulose because a. humans have enzymes that can hydrolyze the β glycosidic linkages of starch but not the α glycosidic linkages of cellulose. b. the monomer of starch is glucose, while the monomer of cellulose is glucose with a nitrogen-containing group. c. humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose. d. humans harbor starch-digesting bacteria in the digestive tract. e. the monomer of starch is glucose, while the monomer of cellulose is galactose.

c. humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.

Which type of interaction stabilizes the alpha helix and the β pleated sheet structures of proteins? a. peptide bonds b. hydrophobic interactions c. hydrogen bonds d. ionic bonds e. disulfide bonds

c. hydrogen bonds

Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components. In animal cells, which of the following organelles contains these hydrolytic enzymes? a. peroxisomes b. mitochondria c. lysosomes d. central vacuoles

c. lysosomes

Which of the following functional groups is hydrophobic? a. amino b. hydroxyl c. methyl d. carboxyl

c. methyl

Which component of the cytoskeleton is responsible for cytoplasmic streaming and muscle contractions? a. microtubules b. intermediate filaments c. microfilaments d. all of the above

c. microfilaments

The tertiary structure of a polypeptide is the a. linear sequence of amino acids in a polypeptide. b. overall three-dimensional shape of a protein composed of more than one polypeptide. c. overall three-dimensional shape of a fully folded polypeptide. d. localized region of a polypeptide chain that forms an α helix or β pleated sheet.

c. overall three-dimensional shape of a fully folded polypeptide.

Which cell would be best for studying lysosomes? a. muscle cell b. nerve cell c. phagocytic white blood cell d. bacterial cell

c. phagocytic white blood cell

The difference between pinocytosis and receptor-mediated endocytosis is that a. pinocytosis increases the surface area of the plasma membrane, whereas receptor-mediated endocytosis decreases the plasma membrane surface area. b. pinocytosis requires cellular energy, but receptor-mediated endocytosis does not. c. pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis is highly selective. d. pinocytosis brings only water molecules into the cell, whereas receptor-mediated endocytosis brings in other molecules as well. e. pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated endocytosis cannot.

c. pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis is highly selective.

The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that a. plant cells are capable of having a much higher surface-to-volume ratio than animal cells. b. animal cells are spherical, whereas plant cells are elongated. c. plant cells contain a large vacuole that reduces the volume of the cytoplasm. d. plant cells have a much more highly convoluted (folded) plasma membrane than animal cells.

c. plant cells contain a large vacuole that reduces the volume of the cytoplasm.

The alpha helix and beta pleated sheet are examples of which level of protein structure? a. tertiary b. quaternary c. secondary d. primary, secondary, tertiary, and quaternary e. primary

c. secondary

Collagen is a protein made of three identical polypeptides composed primarily of alpha helix structure. The alpha helix is an example of a. secondary structure stabilized by covalent bonds. b. secondary structure stabilized by ionic bonds. c. secondary structure stabilized by hydrogen bonds. d. tertiary structure stabilized by hydrogen bonds. e. tertiary structure stabilized by covalent bonds.

c. secondary structure stabilized by hydrogen bonds.

Which of the following is an example of a hydrolysis reaction? a. the reaction of a fat with glycerol, forming fatty acids with the release of water b. the synthesis of two amino acids, forming a peptide bond with the release of water c. the reaction of a fat, forming glycerol and fatty acids with the consumption of water d. the reaction of two monosaccharides, forming a disaccharide with the release of water

c. the reaction of a fat, forming glycerol and fatty acids with the consumption of water

Lactase is an enzyme composed of a single polypeptide that hydrolyzes the disaccharide lactose to produce monosaccharides. The optimal pH for lactase activity is 6. Transfer of lactase to pH 5 results in a substantial decrease in enzyme activity, likely due to the disruption of a. the secondary, tertiary, and quaternary structure of the enzyme. b. the primary and secondary structure of the enzyme. c. the secondary and tertiary structure of the enzyme. d. only the primary structure of the enzyme.

c. the secondary and tertiary structure of the enzyme.

Passive movement of fluids and bacteria from the interior of the small intestine through the space between cells of the intestinal wall can cause serious infection and medical complications. Defects in which of the following would be associated with such a condition? a. middle lamella b. desmosomes c. tight junctions d. gap junctions e. cell walls

c. tight junctions

If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence a. 3'UAACGU5'. b. 5'UGCAAU3'. c. 5'UAACGU3'. d. 5'TGCAAT3'. e. 5'TAACGT3'.

d. 5'TGCAAT3'.

A cage containing male mosquitoes has a small earphone placed on top through which the sound of a female mosquito is played. All the males immediately fly to the earphone and go through all of the steps of copulation. What is the best explanation for this behavior? a. The males learned to associate the sound with females. b. The reproductive drive is so strong that when males are deprived of females, they will attempt to mate with anything that has even the slightest female characteristic. c. The sound is a form of a visual signal, which causes the males to attempt to mate. d. Copulation is a fixed action pattern, and the female flight sound is a sign stimulus that initiates it.

d. Copulation is a fixed action pattern, and the female flight sound is a sign stimulus that initiates it.

Which of the following statements regarding the chemical reaction illustrated in Figure 3.11 is true? (refer to picture on Biochemistry Test) a. It forms a disaccharide. b. It is a hydrolysis reaction. c. It forms two amino acids. d. It results in a peptide bond.

d. It results in a peptide bond.

Red-cheeked salamanders are partially protected from predators because of cardiac glycosides they produce from glands on their back. When ingested, cardiac glycosides disrupt normal heart rhythms. A different salamander species, the imitator salamander, also has red cheek patches, but does not produce cardiac glycosides.This is an example of a. Cryptic Coloration b. Batasian Mimicry c. Aposematic Coloration d. both B and C

d. both B and C

A mutation that disrupts the ability of an animal cell to add polysaccharide modifications to proteins would most likely cause defects in its a. nuclear lamina and extracellular matrix. b. nuclear lamina c. smooth ER and Golgi apparatus. d. extracellular matrix.

d. extracellular matrix.

A molecule with the formula C18H36O2 is probably a a. hydrocarbon. b. carbohydrate. c. nucleic acid. d. fatty acid.

d. fatty acid.

Which structure is common to plant and animal cells? a. wall made of cellulose b. centriole c. chloroplast d. mitochondrion

d. mitochondrion

Which of the following chemical equations describes a dehydration reaction? a. monosaccharide + monosaccharide + H2O YIELDS disaccharide b. disaccharide YIELDS monosaccharide + monosaccharide + H2O c. disaccharide + H2O YIELDS monosaccharide + monosaccharide d. monosaccharide + monosaccharide YIELDS disaccharide + H2O

d. monosaccharide + monosaccharide YIELDS disaccharide + H2O

Which animal cell organelle contains enzymes that transfer hydrogen from various substrates to oxygen? a. vacuole b. mitochondrion c. lysosome d. peroxisome e. Golgi apparatus

d. peroxisome

Some key innovations in the evolution of eukaryotes from a prokaryotic ancestor are membrane-bound organelles. Which of the following organelles or features is likely to be a common component shared by both eukaryotic cells and their prokaryotic ancestors? a. nuclear envelope b. chloroplasts c. mitochondria d. ribosomes

d. ribosomes

Male stalk-eyed flies compete with other males in order to attract female attention. What will result from this behavior? a. ornamented females b. polygamy c. monogamy d. sexual dimorphism

d. sexual dimorphism

In a simple synapse, neurotransmitter chemicals are released by a. axon hillocks. b. cell bodies. c. the dendritic membrane. d. the presynaptic membrane.

d. the presynaptic membrane.

The following steps refer to various stages in transmission at a chemical synapse. 1. Neurotransmitters bind with receptors associated with the postsynaptic membrane. 2. Calcium ions rush into the neuron's cytoplasm. 3. An action potential depolarizes the membrane of the axon terminal. 4. The ligand-gated ion channels open. 5. The synaptic vesicles release neurotransmitters into the synaptic cleft. Which sequence of events is correct? a. 2 ® 3 ® 5 ® 4 ® 1 b. 5 ® 1 ® 2 ® 4 ® 3 c. 4 ® 3 ® 1 ® 2 ® 5 d. 1 ® 2 ® 3 ® 4 ® 5 e. 3 ® 2 ® 5 ® 1 ® 4

e. 3 ® 2 ® 5 ® 1 ® 4

Which of the following statements is consistent with the principle of competitive exclusion? a. Bird species generally do not compete for nesting sites. b. Two species with the same fundamental niche will exclude all other competing species. c. Natural selection tends to increase competition between related species. d. The random distribution of one competing species will have a positive impact on the population growth of the other competing species. e. Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species.

e. Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species.

Which of the following macromolecules contains nitrogen? a. fatty acids only b. nucleic acids only c. proteins only d. both fatty acids and proteins e. both proteins and nucleic acids

e. both proteins and nucleic acids

Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells? a. peroxisomes b. tight junctions c. extracellular matrix d. desmosomes e. gap junctions

e. gap junctions

Neural transmission across a mammalian synapse is accomplished by a. impulses ricocheting back and forth across the synapse. b. the movement of sodium and potassium ions from the presynaptic neuron into the postsynaptic neuron. c. the movement of calcium ions from the presynaptic into the postsynaptic neuron. d. impulses traveling as electrical currents across the synapse. e. impulses causing the release of a chemical signal and its diffusion across the synapse.

e. impulses causing the release of a chemical signal and its diffusion across the synapse.

A graded hyperpolarization of a membrane can be induced by a. increasing its membrane's permeability to Na+. b. decreasing its membrane's permeability to Cl-. c. decreasing its membrane's permeability to H+. d. increasing its membrane's permeability to Ca2+. e. increasing its membrane's permeability to K+.

e. increasing its membrane's permeability to K+.

Which variables define the ecological life history of a species? a. the amount of parental care given after birth, the number of reproductive episodes per year, and the number of years females are capable of producing viable offspring b. the number of offspring produced over a lifetime by a breeding pair and the survivability of the offspring c. timing breeding sessions with optimal environmental conditions and the number of offspring produced during each breeding session d. the ratio of females to males, the length of the breeding season, and the number of offspring for each reproductive episode e. the age at which reproduction begins, frequency of reproduction, and the number of offspring for each reproductive episode

e. the age at which reproduction begins, frequency of reproduction, and the number of offspring for each reproductive episode