AP Bio FRQs
Why is ATP considered the energy currency of the cell?
ATP is called the energy currency of the cell because it is the molecule that all living organisms use for energy.
How are complex macromolecule polymers synthesized from monomers?
Dehydration Synthesis.
What is the difference between endergonic and exergonic reactions?
In an exergonic reaction, energy is released to the surroundings. The bonds being formed are stronger than the bonds being broken. In an endergonic reaction, energy is absorbed from the surroundings.
What is the difference between kinetic and potential energy?
Potential Energy is the stored energy in an object or system because of its position or configuration. Kinetic energy of an object is relative to other moving and stationary objects in its immediate environment.
What is the relationship between amino acids and proteins?
When connected together by a series of peptide bonds, amino acids form a polypeptide, another word for protein. The polypeptide will then fold into a specific conformation depending on the interactions (dashed lines) between its amino acid side chains.
How are monosaccharide building blocks assembled into disaccharides and complex polysaccharides?
Monosaccharides are converted into disaccharides in the cell by condensation reactions. Further condensation reactions result in the formation of polysaccharides. These are giant molecules which, importantly, are too big to escape from the cell.
What are the main cellular structures involved in photosynthesis?
Multicellular autotrophs use chloroplasts, thylakoids, and chloroplasts.
What are the characteristics shared by the natural sciences?
Natural science are different fields of science that relates to the physical world and its phenomena and processes.
What is the role of photosynthesis in the energy cycle of all living organisms?
Photosynthesis captured light and allows autotrophs to make their own food/ energy.
What is the role of enzymes in metabolic pathways?
Some enzymes help to break down large nutrient molecules, such as proteins, fats, and carbohydrates, into smaller molecules. This process occurs during the digestion of foodstuffs in the stomach and intestines of animals.
How does atomic structure determine the properties of elements, molecules, and matter?
An atom is the smallest unit of matter that retains all of the chemical properties of an element. The attraction between the positively charged protons and negatively charged electrons holds the atom together. Most atoms contain all three of these types of subatomic particles—protons, electrons, and neutrons.
What limits the size of a cell?
Cell size is limited by a cell's surface area to volume ratio.
What is the role of cells in organisms?
Cells provide structure for the body, take in nutrients from food and carry out important functions. Cells group together to form tissues, which in turn group together to form organs, such as the heart and brain.
What is the relevance of photosynthesis to living organisms?
Photosynthesis is the number one source of oxygen in the atmosphere and provides food from sunlight, carbon dioxide, and water. it's the primary source of energy.
How and where does photosynthesis occur within a plant?
Photosynthesis occurs in the chloroplasts, and uses the chlorophyll to fully make photosynthesis happen.
What are the substrates and products of photosynthesis?
Photosynthesis uses sunlight, carbon dioxide, and water as substrates. it produces oxygen and glucose.
Identify and describe the properties of life. Why and how does passive transport occur across membranes?
Plasma membranes are selectively permeable; they allow some substances to pass through, but not others. ... The most direct forms of membrane transport are passive. Passive transport is a naturally-occurring phenomenon and does not require the cell to exert any of its energy to accomplish the movement.
What are metabolic pathways?
A metabolic pathway is a linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical reactions catalyzed by enzymes.
What is the structure and role of DNA?
A nucleic acid that contains the genetic instructions for the development and function of living things. All known cellular life and some viruses contain DNA. The main role of DNA in the cell is the long-term storage of information.
How does cholesterol help maintain the fluid nature of the plasma membrane of cells?
Cholesterol functions as a buffer, preventing lower temperatures from inhibiting fluidity and preventing higher temperatures from increasing fluidity.
What is the difference between light microscopy and electron microscopy?
Electron microscopes differ from light microscopes in that they produce an image of a specimen by using a beam of electrons rather than a beam of light. Electrons have much a shorter wavelength than visible light, and this allows electron microscopes to produce higher-resolution images than standard light microscopes.
What is "energy"?
Energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object.
How do enzymes function as molecular catalysts?
Enzymes lower the activation energy of the reaction but do not change the free energy of the reaction. A substance that helps a chemical reaction to occur is called a catalyst, and the molecules that catalyze biochemical reactions are called enzymes.
What are the four major types of lipids?
Fats and oils, waxes, phospholipids, and steroids.
What is the fundamental difference between anaerobic cellular respiration and the different types of fermentation?
Fermentation and anaerobic respiration differ because although they both start with glycolysis, fermentation does not stop with the products of glycolysis, but instead created Pyruvate and continues the same path as aerobic respiration.
How do functional groups determine the properties of biological molecules?
Functional groups are a set of commonly found groups of atoms covalently bonded to carbon in organic molecules. The unique functional groups present on a biomolecule determine reactivity, solubility, and other physical properties that lead to its biological role in living organisms.
What are the roles of tight junctions, gap junctions, and plasmodesmata in allowing cells to exchange materials with the environment and communicate with other cells?
Gap junctions in animal cells are like plasmodesmata in plant cells in that they are channels between adjacent cells that allow for the transport of ions, nutrients, and other substances that enable cells to communicate.
What is the overall result, in terms of molecules produced, in the breakdown of glucose by glycolysis?
Glycolysis begins with glucose and produces two pyruvate molecules, four new ATP molecules, and two molecules of NADH. (Note: two ATP molecules are used in the first half of the pathway to prepare the six-carbon ring for cleavage, so the cell has a net gain of two ATP molecules and two NADH molecules for its use).
What are the differences among ionic bonds, covalent bonds, polar covalent bonds, and hydrogen bonds?
In an ionic bond, an atom gives away one or more electrons to another atom. In a covalent bond, two atoms share one or more electrons. A hydrogen bond is a relatively weak bond between two oppositely charged sides of two or more molecules.
Why does the term "carbon fixation" describe the products of the Calvin cycle?
In carbon fixation, CO2 is attached to RuBP by the enzymes. it results in 6-carbon products which splits into two even 3-carbon compounds.
How does the molecular structure of water result in unique properties of water that are critical to maintaining life?
It is polar, allowing for the formation of hydrogen bonds, which allow ions and other polar molecules to dissolve in water. ... The hydrogen bonds between water molecules give water the ability to hold heat better than many other substances.
What are the reactions in the Calvin cycle described as the light-independent reactions?
Light reactions harness energy from the sun and produce chemical bonds, ATP and NADPH. They require light.
How do plants absorb energy from sunlight?
Most plants contain chlorophyll that absorbs the sun's energy and turns it into chemical energy.
What are the steps of the scientific method?
Observation, Question, hypothesis that answers a question, Prediction based on the hypothesis, Do an experiment to test the prediction, Analyze the results
Describe the levels of organization among living things.
Organelles, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, the biosphere.
Identify and describe the properties of life.
Organized structure, respond to stimuli, reproduction, growth, regulation- nutrient transport, homeostasis- constant internal conditions, energy Processing, adaptation, evolution.
What mechanisms control cellular respiration?
Pathways are regulated through enzymes that catalyze individual steps of the pathway. ATP, ADP, and NADH are molecules that regulate cellular respiration enzymes.
What is the molecular structure of phospholipids, and what is the role of phospholipids in cells?
Phospholipids are a class of lipids that are a major component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. The structure of the phospholipid molecule generally consists of two hydrophobic fatty acid "tails" and a hydrophilic "head" consisting of a phosphate group.
What are the four levels of protein organization?
Primary, secondary, tertiary, and quaternary.
What is the relationship between protein shape and function?
Proteins are composed of amino acid subunits that form polypeptide chains. Enzymes catalyze biochemical reactions by speeding up chemical reactions, and can either break down their substrate or build larger molecules from their substrate.
What are the functions of the major cell structures?
Provides storage and work areas for the cell; the work and storage elements of the cell, called organelles, are the ribosomes, endoplasmic reticulum, Golgi apparatus, mitochondria, lysosomes, and centrioles. Make enzymes and other proteins; nicknamed "protein factories".
What are the products of the citric acid cycle?
The citric acid cycle is a series of reactions that produces two carbon dioxide molecules, one GTP/ATP, and reduced forms of NADH and FADH2.
How do the various components of the cytoskeleton perform their functions?
The cytoskeleton gives a cell its shape, offers support, and facilitates movement through three main components: microfilaments, intermediate filaments, and microtubules.
What is the difference between dehydration (or condensation) and hydrolysis reactions?
The difference between dehydration synthesis and hydrolysis is that in one, bonds are being formed, while in the other bonds are being destroyed. Dehydration synthesis bonds molecules together by removing water. In hydrolysis, water is added to the molecules in order to dissolve those bonds.
How is ATP used by the cell as an energy source?
The enzymatic removal of a phosphate group from ATP to form ADP releases a huge amount of energy which is used by the cell in several metabolic processes as well as in the synthesis of macromolecules such as proteins.
What are the components of the extracellular matrix?
The extracellular matrix has three major components: Highly viscous proteoglycans (heparan sulfate, keratan sulfate, chondroitin sulfate), which cushion cells. Insoluble collagen fibers, which provide strength and resilience.
How does the fluid mosaic model describe the structure and components of the plasma cell membrane?
The fluid mosaic model describes the structure of the plasma membrane as a mosaic of components —including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character.
What is free energy, and how does free energy related to activation energy?
The free energy of a system changes during energy transfers, such as chemical reactions, and this change is referred to as ΔG or Gibbs free energy. The ΔG of a reaction can be negative or positive, depending on whether the reaction releases energy (exergonic) or requires energy input (endergonic).
Predict the likely effect on the ability of substance L to enter the cells if substance L is attached to a large protein instead of free in the culture.
The response indicates that substance L will be unable to enter the cells if it is attached to a large protein OR the response indicates that substance L will be unable to enter the cells if it is attached to a large protein unless there is a specific cell membrane receptor for the protein.
Identify the appropriate negative control the researchers most likely used when measuring the reaction rate in the presence of each organism's enolase.
The response indicates that the appropriate negative control is to measure the reaction rate (at the varying substrate concentrations) without any enzyme present.
Make a claim about the most immediate effect on the fused B-cancer cells if the fused cells are transferred to a growth medium that lacks a source of nitrogen.
The response indicates that the cells will die OR that they will be unable to synthesize DNA and RNA/nucleic acids/nucleotides and amino.
Describe the relationship between the concentration of glucose in the culture medium and the ATP concentration in the cells.
The response indicates that the concentration of glucose appears to have little or no effect on the ATP concentration of the cells.
Determine the external concentration of substance L that will result in one-half of the maximal entry rate.
The response indicates that the external concentration of substance L that will result in one-half of the maximal entry rate is a value other than one between 31 mM and 34 mM.
Describe the characteristics of the phospholipid bilayer that permit small hydrophobic lipid molecules to pass directly across the membrane.
The response indicates that the interior of a phospholipid bilayer is hydrophobic, which allows small hydrophobic molecules to diffuse across the membrane.
Identify the process used to form the covalent peptide bonds that join amino acids into a polypeptide.
The response indicates that the process that joins amino acids into a polypeptide is a dehydration synthesis OR a condensation reaction.
The change in the amino acid sequence illustrated in Figure 1 caused a change in the shape of Receptor X. Based on the R groups of the original and substituted amino acids, explain why Receptor X changed shape.
The response indicates that two amino acids with charged or ionic or hydrophilic R-groups were replaced by two amino acids with uncharged or nonpolar or hydrophobic R-groups.
What is the importance of electrons for the transfer of energy in living systems?
The transfer of electrons between molecules via oxidation and reduction is important because most of the energy stored in atoms is in the form of high-energy electrons; it is this energy that is used to fuel cellular functions.
What are the major structures of prokaryotic cells?
There are four main structures shared by all prokaryotic cells, bacterial or archaean: The plasma membrane, cytoplasm, and ribosomes.
How does the structure of the eukaryotic cell resemble as well as differ from the structure of the prokaryotic cell?
There are several differences between the two, but the biggest distinction between them is that eukaryotic cells have a distinct nucleus containing the cell's genetic material, while prokaryotic cells don't have a nucleus and have free-floating genetic material instead.
What is tonicity, and how is it relevant to passive transport?
Tonicity is the amount of solute in a solution. This is relevant to passive transport because passive transport is the ability to move a solution through a membrane without energy, this involves osmosis as well.
How is pyruvate, the product of glycolysis, prepared for entry into the citric acid cycle?
Two molecules of pyruvate were produced from glycolysis and converted into two molecules of acetyl coenzyme A, two carbon dioxide, and two NADH + H+ molecules through pyruvate oxidation, an intermediate step between glycolysis and the citric acid cycle.
How do electrons move through the electron transport chain and what happens to their energy levels?
As electrons move through the electron transport chain, they go from a higher to a lower energy level and are ultimately passed to oxygen (forming water). Energy released in the electron transport chain is captured as a proton gradient, which powers production of ATP by a membrane protein called ATP synthase.
How is energy released through the hydrolysis of ATP?
ATP hydrolysis is the catabolic reaction process by which chemical energy that has been stored in the high-energy phosphoanhydride bonds in adenosine triphosphate (ATP) is released by splitting these bonds, for example in muscles, by producing work in the form of mechanical energy.
How do carbohydrate metabolic pathways, glycolysis, and the citric acid cycle interrelate with protein and lipid metabolism pathways?
ATP produced by catabolic pathways is used to drive anabolic pathways. many of the intermediated of glycolysis and the CAC are used in the biosynthesis of a cell's molecule.
What are the differences between anabolic and catabolic pathways?
Anabolic pathways are those that require energy to synthesize larger molecules. Catabolic pathways are those that generate energy by breaking down larger molecules. Both types of pathways are required for maintaining the cell's energy balance. ... Catabolic pathways break large molecules into small pieces.
What are the role of acids, bases, and buffers in dynamic homeostasis?
Buffers readily absorb excess H+ or OH-, keeping the pH of the body carefully maintained in the narrow range required for survival. ... The buffer maintaining the pH of human blood involves carbonic acid (H2CO3), bicarbonate ion (HCO3-), and carbon dioxide (CO2).
What is the role of carbohydrates in cells and in the extracellular materials of animals and plants?
Carbohydrates are a group of macromolecules that are a vital energy source for the cell and provide structural support to plant cells, fungi, and all of the arthropods that include lobsters, crabs, shrimp, insects, and spiders.
What are the differences among the different types of endocytosis: (phagocytosis, pinocytosis, and receptor-mediated endocytosis) and exocytosis?
Endocytosis takes particles into the cell that are too large to passively cross the cell membrane. Phagocytosis is the taking in of large food particles, while pinocytosis takes in liquid particles. Receptor-mediated endocytosis uses special receptor proteins to help carry large particles across the cell membrane.
What are the different classifications of carbohydrates?
On the basis of the number of forming units, three major classes of carbohydrates can be defined: monosaccharides, oligosaccharides and polysaccharides.
What is the difference between saturated and unsaturated fatty acids?
Saturated fatty acids lack double bonds between the individual carbon atoms, while in unsaturated fatty acids there is at least one double bond in the fatty acid chain.
What are the differences between short and long wavelengths of light? What wavelengths are used in photosynthesis?
Short wavelengths are high energy, and long wavelengths are low energy radio waves.
What is the relationship between the structure and function of the components of the endomembrane system, especially with regard to the synthesis of proteins?
The endomembrane system processes and ships proteins specified by the nucleus. In the nucleus, DNA is used to make RNA, which exits the nucleus and enters the cytoplasm of the cell. The ribosomes on the rough ER use the RNA to create the different types of protein needed by the body.
How do the molecular components of the membrane provide fluidity?
The integral proteins and lipids exist in the membrane as separate but loosely-attached molecules.
Explain how the model shows selective permeability of the membrane to specific ions.
The response indicates that a membrane channel protein is selective for a specific kind of ion because only one of the two kinds of ion represented can pass through the channel. The response also indicates that ions cannot simply cross directly between the phospholipids of the membrane (although a small lipid-soluble molecule can).
Depending on the organism, the optimal pH for enolase to catalyze its reaction is between 6.5 and 8.0. Describe how a pH below or above this range is likely to affect enolase and its catalytic ability.
The response indicates that a pH below or above this range will most likely cause enolase to denature/change its shape and be less efficient or unable to catalyze the reaction.
Explain how the amino acid substitution shown in Figure 1 is most likely to affect the function of Receptor X.
The response indicates that because function is determined by shape, the function of receptor X is likely to change OR that the structural change might alter the binding of the molecule to receptor X OR that the structural change might alter the ability of receptor X to cause a cellular response.
Describe the role of carbon in biological systems.
The response indicates that carbon is used to build biological macromolecules such as carbohydrates, proteins, nucleic acids, and lipids.
Based on the model, explain whether the molecules shown crossing the membrane require energy to do so.
The response indicates that energy is not required for the substances to cross the membrane because the substances are being passively transported from a region of higher concentration to a region of lower concentration.
Provide reasoning with evidence based on the composition of biological macromolecules to support your claim.
The response indicates that nucleic acids (DNA, RNA, or nucleotides) and amino acids (polypeptides, or proteins) contain nitrogen.
Describe the role of oxygen in cellular respiration.
The response indicates that oxygen is the terminal acceptor of electrons that have passed through the electron transport chain.
Identify the most likely mode of transport across the membrane for substance L. Explain how information provided helps determine the most likely mode of transport.
The response indicates that substance L most likely crosses the membrane by active transport. The response indicates that the cells maintain an intracellular concentration of 120 mM, which is always greater than the concentration of substance L in the culture medium.
Explain how, when the membranes are fused, the polar parts of the phospholipids from one cell will interact with the phospholipids from the other cell and how the nonpolar parts of the phospholipids from one cell will interact with the phospholipids from the other cell.
The response indicates that the polar part of the phospholipids from one cell will align or interact with the polar parts of the phospholipids from the other cell, and nonpolar parts of the phospholipids from one cell will align or interact with nonpolar parts of the phospholipids from the other cell.
In a further experiment, the researchers add a compound to the cell growth medium that both binds and releases protons (H+) and also passes through lipid membranes. Predict the effect of this added compound on ATP production by the cells. Justify your prediction.
-The response indicates that the amount of ATP produced will decrease OR that no ATP will be produced. -The response indicates that the compound is more likely to bind protons where the protons are in greater concentration, in the intermembrane space. It also does not indicate that if the compound then carries the protons across the inner membrane to the matrix, there will no longer be a proton concentration/pH/electrochemical gradient across the inner membrane, and protons will not flow through and power the ATP synthase enzymes.
What is the basic structure of a steroid, and what are examples of their functions?
A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes which alter membrane fluidity; and as signaling molecules.
What is entropy?
A thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system.
What is the structure and roles of RNA?
Complex compound of high molecular weight that functions in cellular protein synthesis and replaces DNA (deoxyribonucleic acid) as a carrier of genetic codes in some viruses.
How do chemical reactions play a role in energy transfer?
Energy plays a key role in chemical processes. According to the modern view of chemical reactions, bonds between atoms in the reactants must be broken, and the atoms or pieces of molecules are reassembled into products by forming new bonds. Energy is absorbed to break bonds, and energy is evolved as bonds are made.
What are functions of fats in living organisms?
Fats play a vital role in maintaining healthy skin and hair, insulating body organs against shock, maintaining body temperature, and promoting healthy cell function. Fat also serves as a useful buffer against a host of diseases.
Why is carbon important for life?
Living things need carbon the most in order to live, grow, and reproduce. Also, carbon is a finite resource that cycles through the Earth in many forms. Also, carbon is so important to life because virtually all molecules in the body contain carbon.
What is the difference between the first and second laws of thermodynamics?
The first and second law are the most frequently used laws in thermodynamics. The first law says that energy can be neither created nor destroyed. The first law is simply another version of the law of conservation of energy. The second law, on the other hand, asserts that some thermodynamic processes are forbidden.
What is the cell theory?
The historic scientific theory, now universally accepted, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells.
What are structural differences between animal and plant cells?
The main structural differences between plant and animal cells lie in a few additional structures found in plant cells. These structures include: chloroplasts, the cell wall, and vacuoles.
How is a proton (H+) gradient established and maintained by the electron transport chain and how many ATP molecules are produced by chemiosmosis?
The proton gradiant generated by proton pumping during the ETC is a stored form of energy. when protons flow back down, their concentration gradient's only route is through the ATP synthase (mitochondrial membrane). 38 molecules of ATP are produced by chemiosmosis.
The researchers predict that for any particular concentration of substrate, the C. aurantiacus enolase-catalyzed reaction is more rapid at 55°C than at 37°C. Provide reasoning to justify the researchers' prediction.
The response indicated that the enolase has a more stable/functional/correct/normal protein structure at the higher temperature of 55°C than at 37°C because the enzyme is from an organism that is adapted to growth at 55°C.
Using the template below that represents the four levels of protein structure, place an X on each level that is expected to be altered as a result of the amino acid substitutions shown in Figure 1.
The response indicates primary and tertiary structure.
Describe the biological need for cells to be surrounded by a membrane that is selectively permeable for different materials.
The response indicates that a cell membrane separates the internal environment of the cell from the external environment OR that a cell membrane that is selectively permeable can help to regulate what molecules move between the differing environments inside and outside of a cell.
What are functions of proteins in cells and tissues?
They do most of the work in cells and are required for the structure, function, and regulation of the body's tissues and organs. Proteins are made up of hundreds or thousands of smaller units called amino acids, which are attached to one another in long chains.
How do electrochemical gradients affect the active transport of ions and molecules across membranes?
To move substances against a concentration or electrochemical gradient, the cell must utilize energy in the form of ATP during active transport.
What are the two types of nucleic acid?
deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
