AP Bio Exam
How many water molecules are used up (or produced) when a polypeptide chain is converted by hydrolysis reactions into 13 amino acids?
12 are used up
Use the following diagram of a short polypeptide to answer the following question: which functional groups or R groups are nonpolar
2 & 3
Which of the following observations is best explained by water's high surface tension
A leaf floats on the surface of a puddle
Which one of the following statements about atoms is false?
A typical atom contains protons & electrons in the nucleus with neutrons orbiting the nucleus
A certain protein molecule consists of 4 subunits: each is a folded polypeptide chain with an alpha helix. Considering this info, which structureal levels of organization must the molecule have?
Primary, secondary, tertiary, & quaternary
Enzymes are required by all living things because enzymes
Properly orient reactants and lower activation energy
An enzyme is an example of a
Protein
Only small amounts of enzymes are required for reactions within cells because enzymes
Are reused
Which of the following best describes the numbered regions
Areas 1 & 3 are polar, since the membrane molecules are aligned with water molecules
The figure represents a rough er. Which of the following best describes the role of the ribosomes
The structure is the location where proteins are synthesized
To model a plant cell, a permeable, nonflexible case is placed around each piece of dialysis tubing. The greatest pressure potential will develop within dialysis tube number
4 (it's mass increases the quickest)
A net movement of water in to the beaker occurs in which following dialysis tubes?
6 (initial mass = 13.8, after 30 mins = 10.1)
A chemical has the formula C18H32O16. It is what?
A carbohydrate
Phenytoin is a prescription drug that is used to treat patients with epilepsy. A side effect of phenytoin is that it can be toxic to mitochondria. Which of the following processes will be most immediately disrupted by the side effect?
ATP synthesis
The concentration of potassium ions in a RBC is much higher than it is in the surrounding blood plasma yet potassium ions continue to move into the cell. The process by which potassium ions move into the cell is called
Active transport
In which of the following life processes is ATP produced? Photosynthesis, Aerobic respiration, anaerobic respiration
All 3
An embedded protein spans the entire cell membrane of a single cell. Which of the following must be true about the amino acids that make up the protein
Amino acids with nonpolar side groups are in contact with the fatty acids region of the cell membrane
Of the following organic compounds, the one that represents a protein is
C708H1130O224N180
A culture of Spirogyra (an autotrophic alga) is maintained in a water solution containing dissolved CO2 & a source of phosphates but lacking nitrogen compounds. A researcher determines the rates of synthesis of several organic compounds found in the Spirogyra before & after several weeks in the water solution. Which of the following graphs best illustrates a likely result of the experiment?
Carbohydrates - both at 10, Proteins - before at 6 & after at 2, lipids - both at 8, nucleic acids - before at 4 & after at 1
Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?
Catabolism
Intact cells of two unknown cell types were placed into solutions with different concentrations of NaCl. Type 1 cells swelled & burst in the solution with the lowest concentration of NaCl. Type 2 cells swelled but did not burst in the solution with the lowest concentration of NaCl. Which of the following descriptions of cell type 1 and cell type 2 are most consisten with the data
Cell type 1 - animal cell surrounded by plasma membrane only cell type 2 - plant cell surrounded by a plasma membrane & cell wall
Salivary amylase is a digestive enzyme found in saliva. It catalyzes the hydrolysis of large starch molecules early in the digestive process. Salivary amylase is unable to break down proteins. Which of the following best explains why salivary amylase is able to break down starches but not proteins
Enzymes are specific to their substrate
Which of the following best describes an advantage that eukaryotes have over prokaryotes?
Eukaryotes have organelles that allow for compartmentalization of cellular process, which increases the efficiency of those processes
A compound with the chemical formula C5H11COOH would be classified as an
Fatty acid
A common laboratory investigation involves putting a solution of starch & glucose into a dialysis bag & suspending the bag in a beaker of water. The investigation is aimed at understanding how molecular size affects movement through a membrane. Which of the following represents the amount of starch, water, & glucose in dialysis bags over the course of the investigation
Glucose decreasing, water increasing, starch remaining the same
The typical energy storage form of carbohydrates in animals is
Glycogen
Liver cells manufacture membrane glycoproteins while adipose cells store fat. Which of the following subcellular strucures is likely to be more prominent in liver cells than in adipose cells
Golgi apparatus
A student peeled the skins from grapes, exposing the cells with membrane that are only permeable to water & small diffusible solutes. The student measured the mass of the peeled grapes. The student then placed each peeled grape into one of the five solutions. After 24 hours, the student removed the peeled grapes from the solutions, measured their final mass, & calculated the percent change in mass. In a second experiment the student placed a peeled grape into a solution containing both small diffusible solutes and solutes to which the membrane is impermeable. Which of the following best explains the differences in water potential between certain solutions & graphes?
Grape soda & NaCl have a lower water potential than the grape because these two solutions caused the grape to lose water (both negative numbers on chart 1)
When water evaporated, breaks occur in what bonds
Hydrogen bonds (the doted line on the picture)
Figure 1 is a diagram of water molecules at the air-water interface at the surface of a pond. Based on figure 1, which of the following best describes how the properties of water at an air-water interface enable an insect to walk on the water's surface
Hydrogen bonds between molecules at the surface of the water provide surface tension, which allows the water surface to deform but not break under the insect
Which of the following is true about the structure of prokaryotic cell represented in the following figure
It has a cell wall exterior to the plasma membrane & ribosomes
Use the following figure to answer the question below. Which statement is the most accurate description of the reaction shown in the figure above?
It represents a polypeptide chain that is broken down through a hydrolysis reaction
Although the water is colder to swim in on the West Coast than on the East Coast of the US, the temp of water is relatively constant in both locations, why?
It takes a large amount of heat energy to raise the temp of water
ATP serves as a common energy source for organisms because
Its energy can be easily transferred to do cellular work
What element would you expect to find in sucrase that is not in sucrose
Nitrogen
The isotopes of carbon, which are an important tool in biological research, differ from each other in
Number of neutrons
Two molecular structures of linoleic acid & palmitic acid, two naturally occurring substances are shown in the figure. Based on the molecular structures shown in figure, which molecule is likely to be solid at room temp?
Palmitic acid, because the absence of carbon-carbon double bonds allows the molecules to pack closely together
If ATP breakdown is inhibited, which of the following types of movement across cell membranes is also inhibited
Passage of a solute against its concentration gradient
Which of the following statements best explains the processes of passive & active transport?
Passive transport is the net movement of substances down a concentration gradient that does not require metabolic energy. Active transport is the movement of substances up a concentration gradient that requires energy
Removal of a cell's ribosomes would directly result in a cell's inability to form which of the following
Peptide bond
Study the molecule. This would most likely be found as a component of
Phospholipid
Which of the following macromolecules is primarily responsible for the insolubility of cell membranes in water?
Phospholipid
In the following diagram of water molecules, the bond labeled x from O to H is a(n)
Polar covalent bond
Substances that are soluble in water are most likely to be
Polar, electrically charged
Includes hemoglobin, collagen, & insulin
Proteins
Which one of the following statements about proteins is false?
Proteins are made from nucleotide monomers
Study the figure below. Which of the following statements best describes how organisms such as rabbits obtain the carbon necessary for building biological molecules?
Rabbits eat plants & break down plant molecules to obtain carbon a& other atoms that the rearrange into new carbon-containing molecules
Salivary glands produce a large quantity of enzymes that are transported out of the secretory cells. Which of the following organelles owuld be in abundance in these cells
Ribosomes
Cells contain smaller components called organelles that are necessary for a cell's survival. Organelle functions have often been compared to components of larger systems. Which of the following functional differences between the rough & smooth ER is explained by the structural dififerences between them?
Rough er can synthesize & package proteins for export, and smooth er cannot
A biochemist was working with an enzyme that she knew was a single polypeptide chain. When she lowered the pH of the enzyme slightly, she found that the enzyme's activity slowed. However, when she returned the pH to the enzyme's normal stage, the enzyme resumed normal activity & speeded up a chemical reaction. Lowering the pH probably altered the enzyme's?
Tertiary structure
DNA & RNA are nucleic acids that can store biological info based on the sequence of their nucleotide monomers. Figure 1 shows a short segment of each of the two types of nucleic acids. Which of the following best describes a structural difference between DNA & RNA?
The backbone of DNA contains deoxyribos whereas the backbone of RNA contains ribose
A spherical bacterial cell has a radius of 3um. The human egg cell has a radius of 100um. Which statement correctly identifies the cell that is able to be more efficient exchange materials with the external environment & provides a correct explanation
The bacterial cell, because it has the largest surface to volume ration
The following question refers to an experiment in which a dialysis-tubing bag is filled with a mixture of 3% starch and 3% glucose & placed in a beaker of distilled water, as shown below. After 3 hours, glucose can be detected in the water outside the dialysis-tubing bag, but starch cannot. Which of the following best describes the condition expected after 24 hours?
The bag will contain more water than it did in the original condition
The carbohydrates glucose, galactose, & fructose have the same chemical formula C6H12O6, but different structural formulas as represented in the figures. Which of the following statements about glucose, galactose, & fructose is most likely true?
The carbohydrates have different properties because they have different arrangements of carbon, hydrogen, & oxygen atoms
You are growing cells in culture and notice that the cells do not look very healthy. After some checking you discover that there is a lot of ethanol in the culture fluid. What is probably wrong with culture?
The cells do not have enough O2
Paramecia are unicellular protist that have contractile vacuoles to remove excess intracellular water. In a experimental investigation paramecia were placed in salt solutions of increasing osmolarity. The rate at which the contractile vacuole contracted to pump out excess water was determined & plotted against osmolarity of the solutions. Which of the following is the correct explanation for the data (rate of contraction decreased as osmolarity of the solution increased)
The contraction rate increases as the osmolarity decreases because the amount of water entering the paramecia by osmosis increases
The air temp ranges of several Southern Cali cities in August are shown in the table below. Which of the following best explains why coastal cities like San Diego have a smaller air temp range than inland cities
The high heat capacity of water allows the ocean to moderate the temp of nearby air & land
Which statement best explains the orientation of the phospholipid molecules in the model?
The hydrophilic phosphate groups of the phospholipid molecules are attracted to the aqueous internal & external environments
A pathogenic bacterium has been engulfed by a phagocytic cell as part of the nonspecific immune response. Which of the following illustrations best represents the response?
The image with the phagocytic cell engulfing the bacterium, lysosomes are attaching to the engulfed bacteria, then being released
The value for water potential in root tissue was found to be W=-0.15 bars. Fi the root tissue is placed in a 0.1M solution of sucrose (W = -0.23 bars) which of these would describe the movement of water
The net flow of water would be from the root tissue into the sucrose solution
Which of the following best describes a feature shown in the diagram that is unique to bacteria
The organism does not have a nuclear membrane surrounding the genetic material
In the early 1950s, a team of researchers led by Erwin Chargaff, conducted a series of experiments related to deciphering the chemical composition of DNA. In one experiment, Chargaff's team examined samples of DNA from different species of sea urchins. The results of this experiment are summarized in the table below.Which of the following results from the experiment is most consistent with the base-pairing rules of DNA?
The percentage of adenine is roughly equal to the percentage of thymine nucleotides across all species in the experiment (in the row, all numbers are 1.02)
The following question refers to an experiment in which a dialysis-tubing bag is filled with a mixture of 3% starch and 3% glucose & placed in a beaker of distilled water, as shown below. After 3 hours, glucose can be detected in the water outside the dialysis-tubing bag, but starch cannot. If instead of the bag, a potato slice were placed in the beaker of distilled water, which of the following would be true of the potato slice
The potato would gain mass
The primary function of the kidney is to exchange molecules across a membrane between the blood & urine. One type of kidney cell has a basic rectangular shape, except for a single surface, which is lined with tiny, finger-like projections that extend into the surrounding extracellular space. Which of the following best explains the advantage these projections provide the cell?
The projections increase the surface area to volume rat of the cell, which allows for ore efficient nutrient exchange with the environment
Which of the following statements best helps explain the reaction specificity of an enzyme
The shape and charge of the substrates are compatible with the active site of the enzyme
A cytologist uses a microscope to compare a human hepatocyte & a human epithelial cell. She observes that the smooth er of the hepatocyte is larger and contains more folds than the smooth er of the epithelial cell. Which of the following is best supported by the observation
They hepatocyte is able to synthesize lipids more efficiently than the epithelial cell
The human body is capable of digesting the complex polymer starch into simpler subunits. This digestive process requires the presence of water & enzyme amylase in order to break down starch into maltose. This is depicted below. Which of the following statements best describes the digestion of starch into maltose?
This is a hydrolysis reaction that requires water to break down a complex polymer into simpler subunits
The following table shows the relative percentages of elements in a certain biological molecule. Which best describes the biological molecules (chart includes C=38%, N=17%, P=10%, O=31%, H=4%)
This molecules is a nucleic acid
The molecule shown below is a(n)
Unsaturated fatty acid
A sample of human blood was placed in a test tube containing a physiological saline solution (0.9% sodium chloride). This type of solution is often sued intravenously to quickly rehydrate patients. A drop of the blood from the test tube was placed on a slide and red blood cells were observed under a microscope. Three possible outcomes are diagrammed below. Which of the following best predicts which diagrammed microscope view the laboratory worker would see and best explains why
View 2 (normal looking cells) because the rate of water movement into the RBC's equals the rate of water movement out of the cells
The diagram shows how water can adhere to the xylem in the stems of plants, which contributes to water movement in the plant. Which of the following best explains how water is able to move upward from the roots of a plant, through its xylem in the stem & out to the leaves
Water & the xylem are both polar. Water molecules have the ability to form hydrogen bonds with each other & with the walls of xylem
Which of the following best explains water's ability to dissolve certain substances such as glucose, but remain separate from other substances such as oils?
Water molecules are polar, consisting of two partially positive hydrogen atoms, and one partially negative oxygen atom
You have a large, healthy philodendron that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark?
While it did have access to light before you left, the plant stored energy in the form of sugars or starch, and it was able to derive energy from tose during your vacation
Testosterone is a small steroid hormone that is important in a cell signaling. Which of the following indicates where testosterone enters a cell & why it is able to cross at the point
Because testosterone is nonpolar it can diffuse through the membrane
How are dietary fats & human sex hormones similar
Both are insoluble lipids
Which of the following is a characteristic of mitochondria & chloroplast that supports the endosymbiotic theory
Both contain DNA molecules
Which of the following best depicts the tertiary structures of the two proteins in water?
Both original & mutated protein are in a ball (folded)
Includes glycogen, chitin, cellulose, & glucose
Carbohydrates
Sulfa drugs act by binding to and fully occupying the active site on an enzyme that catalyzes a step in the production of folic acid. In this situation, the drug could best be described as a
Competitive inhibitor
All of the following are examples of hydrolysis except
Conversion of glucose & galactose to lactose
Which of the following types of reactions would decrease the entropy within a cell
Dehydration synthesis
Which of the following describes the most likely location of cholesterol in an animal cell
Embedded in the plasma membrane
White blood cells secrete large amounts of antibody proteins in response to an infection. Through what process are these proteins released
Exocytosis
Which of the following processes is the reverse of dehydration synthesis?
Hydrolysis
Penicillin is a toxic to new bacterial cells because it prevents cell wall formation, causing the cells to burst. This indicated that the bacteria live in a()
Hypotonic environment
Some people in your study group say they don't understand what a polar molecule is. You explain that a polar molecule...
Is slightly negative at one end and slightly positive at the other ned
In living organisms, lipids function mainly as
Sources of stored energy & components of cellular membranes
Synthesized from a cholesterol precursor
Steroids
Intravenous (IV) solutions administered to patients are normally isotonic. Which of the following is most likely to occur if an IV of distilled water is administered to a patient
The cells that are exposed to hypotonic solutions will expand as water moves osmotically into the cells from the blood
Lactose is a dimer sugar composed of two monmeric subunits ((galactose & glucose). In an investigation, researchers placed intestinal cells in a nutrient medium containing lactose. The researchers determined that the lactose had broken down into galactose & glucose in the manner depicted in the reaction below. The cells were then modified and re-exposed to the lactose medium. The researchers were no longer able to detect the presence of glucose & galactose. Which of the following conclusions best explains an outcome of this modification?
The cells were unable to hydrolyze the lactose dimer into its monomeric subunits
Bodies of water, such as ponds, freeze from top to bottom, forming a sheet of ice. This can help aquatic organisms survive during cold winter months. Which of the following statements best explains why the ice floats on the surface?
The crystalline structure of solid ice makes it less dense than liquid water
Researchers claimed that a particluar organelle orginated from a free-living prokaryotic cell that was engulfed by a larger cell. Which of the following provides evidence to best support the claim?
The organelle has a double membrane
Which of the following forms of energy is least available to accomplish cellular work
Thermal energy (heat)
Which of the following statements concerning unsaturated fats is correct?
They have double bonds in the carbon chains of their fatty acids
Used for insulation & buoyancy in marine Arctic mammals
Triglycerides
Small, nonpolar, hydrophobic molecules
easily pass through a membrane's lipid bilayer.
