Unit 1: 

• What causes different chemical properties in isomers?

  • The different arrangements of their molecules

• How is biological information coded in a DNA molecule?

  • The linear sequence of the base pairs

• How does the structure of ice benefit the organisms that live in the water below?

  • The water molecules in ice are farther apart than those in liquid water, so the ice floats, maintaining the warmer, denser lake at the bottom

• What properties must an amino acid have to be incorporated into a polypeptide?

  • The ability to form a covalent bond with both its NH2 group and its COOH group

• What is a common feature of the linking of monomers to form macromolecules?

  • Monomers are joined by a covalent bond, and a water molecule is produced

• If a mutation occurs in a polypeptide chain, how might the change affect the structure and function of the protein?

  • The R-group of the new amino acid has different chemical properties than the R-group of the original amino acid, which will cause the protein to misfold and not function properly in the cell

• In a phosphorus-limited environment, the production of which macromolecule would be affected the most?

  • Nucleic acids

• What is a key difference among the 20 amino acids used to make proteins?

  • Some amino acids are hydrophobic

• Depending on the arrangement of atoms in the ring structure of a monosaccharide, it may have which trait compared to its linear structure?

  • A different function

• How does the hydroxyl group affect the properties of a simple sugar?

  • They increase solubility of simple sugars

  • Can also increase the electronegative of simple sugars, but not useful for sugar properties

• What happens when a glycosidic bond is formed?

  • A monosaccharide unit is joined to either another monosaccharide or to a chain of monosaccharides, and a water molecule is released

• The secondary structures of proteins are stabilized by which type of interaction?

  • Hydrogen bonds

• What is true of both proteins and carbohydrates?

  • Both are formed by dehydration synthesis reactions

• What is the major mechanism of change over time?

  • Natural selection

• Many organisms depend on sugar as a source of energy for the cell. This observation suggests that the pathways that break down sugars:

  • Arose early in life’s history

• What type of bond is formed between a sodium ion and a chloride ion?

  • Ionic

• Protein,s nucleic acids, and carbohydrates are all

  • Polymers made up of repeating subunits

• Which property of water allows it to travel upward from the roots to the leaves of a tree?

  • Cohesion

• What is a sign in the name of something that signals it is a carbohydrate?

  • It ends in -ose (sucrose, glucose, lactose, etc.)

• What is the difference between saturated and unsaturated fats?

  • Saturated fats tend to be solid at room temperature; unsaturated fats are liquid at room temperature

• What determines the function of a protein?

  • The protein’s specific structure

• How do you know if a nucleotide is of RNA or DNA?

  • Whether it has a hydroxyl group or hydrogen atom on its 2’ carbon

  • Sugar identity

  • Nitrogen base identity (T vs. U)

• Pyrimidine vs. purine; what structure do they have?

  • Types of nitrogenous bases - pyrimidines have a single-ring structure (thymine, cytosine, uracil), while purines have a double-ring structure (adenine, guanine)

• What are the 4 main ideas from biology and an example of each

  • Information storage and transmission - Central Dogma

  • Systems interaction - different organisms interact with each other to create a variety of biomes and ecosystems with diversity of life

  • Change over time/evolution - adaptation allows organisms to have the most beneficial traits to survive and reproduce

  • Energetic - organelles of a cell function to help the cell live, thrive, and reproduce (mitochondria, ribosomes, etc.)

• What is the DNA backbone composed of?

  • Bonds between alternative sugars and phosphates of nucleotides; the 5’ phosphate end of one nucleotide bonds with the 3’ hydroxyl end of another nucleotide, and so on

• What types of bonds are inside of DNA? Why is that important?

  • Hydrogen bonds between nitrogenous bases - hydrogen bonds are weak so they’re able to be broken more easily than other types of bonds; DNA needs to break the bonds to form RNA, so the weak hydrogen bonds make breaking the bonds and making RNA easier

• How do the properties of water contribute to transpiration, thermoregulation, and plasma membrane function?

  • Transpiration: sweating - cohesion and hydrogen bonding (weak) take away heat energy and result in evaporation

  • Thermoregulation: as a result of water’s polarity and strong hydrogen and covalent bonds, it takes a lot of energy to break those bonds. The specific heat capacity is high for water because it takes a lot of energy to break the hydrogen and covalent bonds. As a result, water is increasingly resistant to outside changes in temperature and since organisms are mostly made of water, they’re also able to resist environmental temperature changes and regulate their body temperature (thermoregulation).

  • Plasma membrane function: water’s polarity means that certain substances interact with water and others don’t. Other polar molecules will want to interact with water because they’re soluble, while nonpolar molecules will avoid interactions with water because they’re insoluble and hydrophobic. Thus, the hydrophilic parts of the plasma membrane (phospholipid head) will be on the exterior, while the hydrophobic parts (phospholipid tails) will be on the interior. This allows the plasma membrane to effectively function as a boundary between the outside/inside parts of the cell, since the hydrophobic inner structures prevent water from entering, and the hydrophilic parts can interact with water.

• What type of modification happens to amino acids to become functional proteins?

  • Post-translational modification: an R group is added to the amino acid, making it functional

• The protein CFTR is made of 1480 amino acids linked together in a chain. Some humans produce a version of the protein in which phenylalanine (an amino acid) has been deleted from position 508 of the amino acid chain. What best describes how the amino acid deletion will affect the structure of the CFTR protein?

  • It will affect the primary, secondary, and tertiary structures of the CFTR protein

Unit 2:

• Which process is most likely to occur as a result of an animal cell receiving a signal to initiate apoptosis?

  • Lysosomes will release digestive enzymes into the cytosol

• Which of the following experimental changes would allow the scientist to observe transport of a solute across the artificial membrane?

  • Use a small, nonpolar solute instead of a protein

• Which statement best describes the effect of water transport across the cell membrane if the aquaporin in the figure ceases to function?

  • Water Molecules will still be able to move across the cell membrane but at a slower rate

• What is a feature that is unique to archaea and bacteria?

  • No nuclear membrane surrounding its genetic material

• How is the structure of mitochondria in muscle cells different than it is in other cells because of the high energy demands of mitochondria?

  • The inner membrane of the mitochondria in muscle cells should have more folds to increase surface area, allowing more ATP to be synthesized

• What supports the claim that certain organelles within eukaryotic cells evolved from free-living prokaryotic cells?

  • Some organelles contain their own DNA that is more similar to prokaryotic DNA in structure and function than to the eukaryotic DNA found in the cell’s nucleus

• Which of the following claims is scientifically accurate and consistent with an observation that a decrease in lysosome production within a cell leads to a decline in mitochondrial activity?

  • Fewer lysosomes will be available to break down macromolecules to provide the necessary nutrients for cellular respiration

• The newly synthesized protein is transported directly from the endoplasmic reticulum to which of the following?

  • The Golgi Complex

• A spherical bacterial cell has a radius of 3 um. The human egg cell has a radius of 100 um. Which statement correctly indicates the cell that is able to more efficiently exchange materials with the external environment and provides a correct explanation?

  • The bacterial cell, because it has the largest surface-to-volume ratio

• Which 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 and external environments

• Which additional investigation can be used to determine when the cells are in an isotonic solution?

  • Increasing the salinity of the environment a little at a time until the ATP usage reaches a minimum

• Most bacteria are small organisms with small volumes. Because of their size, bacteria can sometimes obtain nutrients by diffusion alone. In addition, bacteria contain numerous active transporters that move nutrients into the bacteria. What explains the need for active transporters in bacteria?

  • Diffusion can bring nutrients into the bacteria across the membrane only if their concentration is higher outside the bacteria than inside

• Characteristics of the active transport pump used to move sodium ions across the membranes of gill cells in a freshwater fish:

  • Requires energy

  • Has a specific binding site for ATP

  • Has a specific binding site for sodium ions

  • Is a protein

  • DOES NOT use osmosis to carry sodium ions into the cells

• An investigator wants to understand whether a newly found membrane protein is involved in membrane transport of a certain particle. What will help determine whether the new membrane protein is a channel protein involved in membrane transport?

  • Add more of the proteins to the plasma membrane and measure the rate of the particle movement

• What is likely to occur as a result of an animal cell receiving a signal to initiate apoptosis?

  • Lysosomes will release digestive enzymes into the cytosol

• A scientist designed an experiment to test an artificial membrane that mimics the phospholipid bilayer of a cell. The scientist built a tube that was divided by an artificial membrane and filled with distilled water. The scientist put a known amount of a protein into the water on one side of the membrane. After some time, the scientist measured the concentration of the protein on either side of the membrane but found that there had been no change. What experimental change would allow the scientist to observe transport of a solute across the artificial membrane?

  • Use a small, nonpolar solute instead of a protein

• Which statement best describes the effect on water transport across the cell membrane if the aquaporin in the figure ceases to function?

  • Water molecules will still be able to move across the cell membrane but at a slower rate

• Muscle cells have high ATP demands. Which of the following is a scientific claim about how the structure of the mitochondria in muscle cells should be different than it is in other cells because of the high energy demands of mitochondria?

  • The inner membrane of the mitochondria in muscle cells should have more folds to increase the surface area, allowing more ATP to be synthesized

• Researchers propose a model to explain variation in phytoplankton cell sizes in a marine environment. They base their model on the idea that smaller cells absorb nutrients more efficiently. The researchers predict that the mean diameter of phytoplankton cells will change by 50 micrometers for every 5-kilometer increase in distance from the shore because of a gradual decrease in nutrient availability. To test their model, the researchers determine that the phytoplankton cells found closest to shore have a mean diameter of 900 micrometers. Based on the model, what will be the mean diameter of the phytoplankton cells that are found 25 kilometers from shore?

  • 650 micrometers

  • Other options: 875, 925, 1150 micrometers

• Plant cell walls are composed of cellulose, while fungal cell walls are composed of chitin. A group of scientists hypothesize that this difference means the cell wall has largely different functions in plant cells and fungal cells. Alternatively, another group of scientists hypothesize that despite their biochemical differences, plant and fungal walls serve similar functions. Which of the following observations would best support the alternative hypothesis described above?

  • In both plant and fungal cells, the cell wall surrounds the outside of the cell membrane

• A team of biologists develop a new drug, and one team member hypothesizes that the drug is incapable of freely passing across the plasma membrane and requires the help of membrane proteins to enter cells. Alternatively, another biologist on the team hypothesizes that the drug can diffuse passively across the plasma membrane like oxygen and carbon dioxide can. Which of the following, if true about the drug, supports the alternative hypothesis that the new drug will exhibit simple diffusion across the plasma membrane?

  • The drug is a small nonpolar molecule

• An investigator wants to understand whether a newly found membrane protein is involved in membrane transport of a certain particle. Which investigation will help determine whether the new membrane protein is a channel protein involved in membrane transport?

  • Add more of the proteins to the plasma membrane and measure the rate of the particle movement

• During a lab a student is given a saliva sample from an unidentified animal. The student isolates a few cells from the saliva and examines the cells under a microscope. In one of the cells, the student observes an organelle that is able to replicate itself independently of the other organelles and contains its own DNA. Identify which organelle the student observed.

  • The mitochondrion

• Large numbers of ribosomes are present in cells that specialize in producing which molecules?

  • Proteins

• Which organelles are extremely important to plant cells for the regulation of water and water pressure?

  • Vacuoles

• Which is true of lysosomes?

  • Small sacks with pores/contains digestive enzymes that get rid of waste, worn-out cell parts, and captured invaders

• Why do viruses not classify as living organisms? Why are they able to achieve an extremely small size not found in any prokaryotes/eukaryotes?

  • Viruses don’t have a nucleus or organelles so they can’t live on their own. They’re able to be very small because they don't need to have organelles or a nucleus inside of them, so their volume is extremely small because their insides are quite empty, making the entire virus small.

• The eukaryotic protozoan parasite P. falciparum is the causative agent of malaria. P. falciparum cells contain an organelle called the apicoplast. Apicoplasts synthesize precursors of biomolecules that are required for growth and reproduction of the parasite. Based on figure 1, describe two pieces of evidence a researcher could use to support the claim that apicoplasts evolved from free-living, prokaryotic organisms.

  • Has a double membrane - evolved from 2 distinct organisms with their own membranes that underwent endocytosis and became the singular organelle of apicoplast with 2 membranes

  • Has its own DNA that’s separate from the DNA of the entire cell - apicoplast has its own nucleus (DNA is in nucleus) and likely came from distinct, free-living organisms

• Cystic fibrosis is a genetic condition that is associated with defects in the CFTR protein. The CFTR protein is a gated ion channel that requires ATP binding in order to allow chloride ions to diffuse across the membrane. In the provided model of a cell, draw arrows to describe the pathway for production of a normal CFTR protein from gene expression to final cellular location.

  • nucleus through ER to golgi to plasma membrane (NO mitochondrion - is only for ATP so protein wouldn’t go through it)

• Difference between primary secondary active transport - how is one of them dependent on the other

  • Primary directly uses cellular energy of ATP to move molecules against concentration gradient; secondary indirectly uses ATP to transport molecules as a result of a proton gradient

  • Secondary is dependent on primary: once primary uses ATP to transport proteins, it creates a concentration gradient of protons as a result of the protein transport. Secondary then uses the concentration gradient created by primary active transport to move molecule across the cell

• What is the name of the model that best describes our understanding of the cell membrane?

  • Fluid mosaic model

Unit 3:

• A researcher claims that the synthesis of ATP from aDP and inorganic phosphate is essential to cellular function. What best helps justify the researcher’s claim?

  • ATP hydrolysis is an energy-releasing reaction that is often coupled with reactions that require an input of energy

• In chloroplasts, ATP is synthesized from aDP plus inorganic phosphate in a reaction catalyzed by ATP synthase molecules that are embedded in the thylakoid membrane. What provides evidence to support the claim that no ATP will be synthesized in the absence of a proton gradient across the thylakoid membrane?

  • No ATP is synthesized when channel proteins that allow the free passage of protons are inserted into the thylakoid membrane

• A researcher claims that different metabolic pathways allow bacteria to use different molecules as sources of matter and energy. What best helps justify the researcher’s claim by providing a relevant example?

  • E. coli bacteria reproduce in liquid media containing either glucose or galactose

• A scientist claims that Elysia chlorotica, a species of sea slug, is capable of photosynthesis. What provides the best evidence to support the claim?

  • Elysia chlorotica grows when exposed to light in the absence of other food sources

• Which statement accurately describes a similarity between photosynthesis and cellular respiration?

  • Both increase the entropy of the cell

• In a study to evaluate new agricultural products, researchers treated plants with an experimental synthetic chemical to see if it would kill the plants. The researcher observed that after the chemical treatment, the plants continued to consume water and produce oxygen, but they stopped producing ATP and NADPH. The plants subsequently died as a consequence of having insufficient ATP. Based on the data provided, which is the most likely description of the chemical activity?

  • The chemical probably inhibits the photosynthetic electron transport chain

• Anaerobic respiration still has mitochondria, just substitutes oxygen for something else

• Fermentation produces intermediate and NADPH and doesn't have mitochondria

• Alcohol/ethanol fermentation produces 2 ethanol molecules and carbon dioxide

• A researcher proposes a model of an enzyme-catalyzed reaction in which a reactant is converted to a product. The model is based on the idea that the reactant passes through a transition state within the enzyme-substrate complex before the reactant is converted to the product. What best helps explain how the enzyme speeds up the reaction?

  • The enzyme’s active site binds to and stabilizes the transition state, which decreases the activation energy of the reaction

• What 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

• The enzyme hexokinase catalyzes the conversion of glucose to glucose-6-phosphate, which is an important step in glycolysis. The reaction involves the transfer of a phosphate group from ATP to glucose. Either a glucose molecule or a water molecule can fit in the active site of hexokinase. The presence of a water molecule in hexokinase’s active site would result in the hydrolysis of ATP to ADP instead of the conversion of glucose to glucose-6-phosphate. What best helps explain the reaction specificity of hexokinase?

  • Glucose has the right shape and charge to cause hexokinase to undergo a structural change needed for catalysis, whereas water does not.

• A researcher designs an experiment to investigate the effect of environmental temperature on the function of an enzyme. For each trial included in the experiment, the researcher will add the enzyme and its substrate to an aqueous buffer solution and then measure the amount of product formed over 20 minutes. What must remain the same for all trials of this experiment?

  • The initial concentration of the substrate

• Alcohol dehydrogenase (ADH) is an enzyme that aids in the decomposition of ethyl alcohol into nontoxic substances. Methyl alcohol acts as a competitive inhibitor of ethyl alcohol by competing for the same active side on ADH. when attached to ADH, methyl alcohol is converted to formaldehyde, which is toxic in the body. What best predicts the effect of increasing the concentration of substrate (ethyl alcohol), while keeping the concentration of the inhibitor (methyl alcohol) constant?

  • Competitive inhibitors will decrease because the proportion of the active sites occupied by substrate will increase

• A researcher claims that only a portion of the light energy captured by green plants is available for growth and repair. What best helps justify the researcher’s claim?

  • As light energy is converted to chemical energy by metabolic processes, some of the energy is lost as heat

• In addition to the pigments commonly associated with photosynthesis, a certain photosynthetic species contains two additional pigment types. What best supports the claim that this species is better adapted to environmental changes than other photosynthetic species are?

  • The additional pigments allow the species containing them to harvest energy from wavelengths of light that the other photosynthetic species cannot use

• Which statement is true regarding Earth’s earliest organisms?

  • These organisms likely carried out fermentation and may have had rudimentary proton pumps

• Which stage in cellular respiration produces carbon dioxide?

  • The Krebs cycle

• Many chemical reactions that take place inside the cell require an input of energy. Which best describes how these reactions can occur?

  • The reactions utilize energy released from hydrolysis of ATP

• What types of reactions have a net use of energy?

  • Anabolic and endergonic

• What type of inhibitor binds to the active site?

  • Competitive

• How does ADP turn into ATP?

  • By adding a phosphate

• The folded inner membrane in mitochondria increase its 

  • Surface area

• What is the ultimate source of energy?

  • Solar energy

Unit 4:

• Which of the following observations provides the best evidence that acetyl-CoA negatively regulates pyruvate dehydrogenase activity?

  • The rate of the pyruvate dehydrogenase-catalyzed reaction is slower in the presence of a higher concentration of acetyl-CoA

• Antidiuretic hormone (ADH) is important in maintaining homeostasis in mammals. ADH is released from the hypothalamus in response to high tissue osmolarity. In response to ADH, the collecting duct and distal tubule in the kidney become more permeable to water, which increases water reabsorption into the capillaries. The amount of hormone released is controlled by a negative feedback loop. Based on the model presented, what expresses the proper relationship between osmolarity, ADH release, and urine production?

  • As tissue osmolarity rises, more ADH is released, causing less water to be excreted as urine

• Cancer can result from a variety of different mutational events. What is LEAST likely to result in the initiation of a cancer tumor?

  • A defect in a cell-cycle checkpoint prevents a cell from entering the S phase

• Most cells that have become transformed into cancer cells have which of the following characteristics when compared to normal, healthy cells?

  • Shorter cell cycles

• A human liver cell reaches the end of G1 but fails to move into S phase researchers treat the cell with chemicals that stain the DNA to make it visible. The stains indicate that the liver cell’s DNA is undamaged. What is a possible explanation for why the cell can’t enter the S phase?

  • The cyclin-CDK complex for G1 is unable to form

• Receptor proteins in cell signaling and cyclin-dependent kinases (CDKs), in the regulation of the cell cycle function similarly in which way?

  • They both change shape and activate upon binding a ligand or cyclin

• Cancers that spread by metastasis

  • Usually include many different mutations in the DNA

• Eukaryotic cells that don’t divide

  • Remain in the G0 phase most of the time

• Which of the following processes take roughly 90-95% of the time of cellular division?

  • Interphase

• The genetic material of the daughter cells (after mitosis) are…

  • Identical to the parent cell’s genetic material

• How is a hydrophobic signal molecule’s effect on the cell different from that of a hydrophilic signal molecule?

  • Hydrophobic easily passes through the membrane and phospholipid bilayer, binds to a receptor on intracellular domain and permanently changes the cell

  • Hydrophilic is harder to pass through the membrane and bilayer, binds to a receptor on extracellular domain, has a short-lived effect and needs to be redone if needed again

• Which feedback mechanism is associated with negative feedback loops and why?

  • Homeostasis: stimulus disrupts balance so cell acts to restore that balance, but the cell is sensitive to its own output and needs to downplay response so the balance remains