Biology

(Exam 1 part b: Chapter 3) When ammonia (NH3) is dissolved in a solution, it accepts hydrogen ions from its surroundings. Ammonia is therefore a(n)

base

(Ch. 5) When yeast cells are deprived of oxygen, they

can produce a small amount of ATP along with ethanol as a byproduct. Yeast cells undergo fermentation in the absence of oxygen, which allows them to produce ATP through glycolysis alone, with ethanol and carbon dioxide as a byproduct. Lactic acid is produced by muscle cells undergoing fermentation.

(Exam 1 part b: Chapter 3) The central element found in organic molecules is

carbon

(Exam 1 part b: Chapter 3) Carbon's prominence in living systems can be explained by the fact that

carbon-based molecules can form long chains and rings.

(Ch. 3) Sodium chloride (NaCl) dissolves well in water because it

has charges that allow it to interact with water. Water is a polar molecule that interacts well with other substances with full and partial charges. In sodium chloride, the sodium ion has a full positive charge that interacts with the partial negative charges on oxygen atoms. The partially positively charged hydrogen atoms of the water molecule interact with the negative chloride ion.

(Exam 1 part b: Chapter 3) Ionic bonds ________, whereas covalent bonds ________.

hold together oppositely charged atoms; hold together atoms that share electrons

(Exam 1 part b: Chapter 3) Individual water molecules orient toward each other because of the ________ bonds that form between them.

hydrogen

(Ch. 3) Hydrogen bonds are

weak chemical bonds that hold separate molecules together. Hydrogen bonds form between molecules, such as between the hydrogen and oxygen ends of neighboring water molecules, to help stabilize a given volume of these molecules.

(Exam 2 part a :Chapter 4) Which of the following statements best describes the differences between the nuclear envelope and the plasma membrane?

The nuclear envelope consists of two concentric phospholipid bilayers, while the plasma membrane is only one phospholipid bilayer. Both membranes are selectively permeable and have pores.

(Ch. 3) The elements carbon, hydrogen, and oxygen

are composed of matter. The chemical building blocks called elements are made of matter. Carbon, hydrogen, and oxygen cannot be compounds because they only consist of a single element.

(Exam 1 part b: Chapter 3) When sodium chloride (Na+Cl−) is dissolved in water, the sodium ion is

attracted to the oxygen atoms of water molecules.

(Exam 1 part b: Chapter 3) Of the following values, which indicates the MOST basic pH?

10

(Exam 1 part b: Chapter 3) If iodide ions (I−) were dissolved in water, they would be attracted to

A and C

(Ch. 5) Which of the following statements about enzymes is FALSE?

A specific enzyme can catalyze a variety of chemical reactions. Enzymes are highly specific and generally only catalyze a single type of chemical reaction. The other statements are part of the definition used to categorize a catalyst as an enzyme.

(Ch. 5) The molecule ________ is produced to carry energy and is broken down during cellular processes to use that energy.

ATP ATP fuels metabolic reactions. Energy is released when it is broken down to ADP and a free phosphate.

(Exam 1 part b: Chapter 3) Which of the labeled areas of the water molecule pictured below possesses a partial negative charge?

B only

(Ch. 4) Which of the following cell structures are typically found in plant cells but not found in animal cells?

Cell wall, chloroplasts, and large central vacuole Golgi apparatuses, lysosomes, smooth ER, rough ER, mitochondria, ribosomes and nuclei are found in both plant and animal cells.

(Ch. 4) Which of the following cell structures can be found in both prokaryotes and eukaryotes?

Cytoplasm, plasma membrane, ribosomes Nuclei, the two types of ER, Golgi apparatuses, and lysosomes are found only in eukaryotic cells.

(Ch. 3) Which of the following is NOT a type of monomer?

DNA DNA is a polymer made from nucleotide monomers. The remaining choices are monomers of carbohydrates, proteins, and nucleic acids.

(Ch. 5) Which of the following is closely associated with mitochondria?

Krebs cycle Chloroplasts (not mitochondria) contain thylakoids. The Calvin cycle occurs in the chloroplast while the Krebs cycle occurs in the mitochondria. Glycolysis occurs in the cytoplasm.

(Ch. 4) Which of these structures is the location of cellular respiration, which produces ATP for the cell?

Mitochondrion The cytoskeleton provides internal organizational and structural support for the cell. The chloroplast performs photosynthesis while the large central vacuole typically stores water and solutes.

(Ch. 4) Which of the following structures is considered an organelle?

Vacuole While the vacuole, cytosol, microtubules, and plasma membrane are all cellular components, the vacuole is the only one listed that is an organelle because it is a membrane-enclosed structure. Found in plant cells, the vacuole serves as a type of storage compartment for the cell.

(Exam 1 part b: Chapter 3) In making her morning tea, Dorothy drops a sugar cube into the hot water. She stirs the mixture but no longer sees the sugar cube at the bottom of her mug. In this scenario, the sugar is

a solute

(Exam 1 part b: Chapter 3) A solution with a pH of 3 is

acidic

(Exam 1 part b: Chapter 3) The most basic solution in the figure shown below is

borax

(Exam 1 part a: Chapters 1 & 2) Which of these characteristics of living organisms are present in viruses?

can evolve as groups

(Ch. 5) Metabolic reactions that break down complex molecules into smaller compounds, thereby releasing usable energy for the cell, are best described as

catabolic This is the definition of catabolic reactions. Photosynthesis is anabolic.

(Exam 1 part b: Chapter 3) Carbon is an example of a(n)

element

(Exam 1 part b: Chapter 3) Which of the following is an organic compound?

methane (CH4)

(Exam 1 part b: Chapter 3) Which of the following solutions has the highest concentration of free H+ ions?

pH 1

(Exam 2 part a :Chapter 4) The plasma membrane of some white blood cells contain ________ proteins that bind with proteins of cells such as bacteria that have invaded the human body.

receptor

(Exam 2 part a :Chapter 4) Which of the following would be likely to require facilitated diffusion to move across the plasma membrane?

sodium ions (Na+), hydrogen ions (H+), sugars, and amino acids

(Exam 1 part b: Chapter 3) The highest concentration of free hydrogen ions is found in

stomach acid

(Exam 1 part b: Chapter 3) The most acidic solution in the figure shown below is

stomach acid

(Exam 1 part b: Chapter 3) Ice floats on water because

the distance between water molecules in ice is greater than in liquid water.

(Ch. 3) In order to determine the atomic mass of an atom, one needs to know

the number of protons and neutrons. When the number of protons and neutrons in an atom are added together, they provide the atomic mass of that atom.

(Exam 1 part b: Chapter 3) Which of the following pieces of evidence would best demonstrate that a bacterium found on an asteroid originated in outer space?

the presence of right-handed amino acids in the bacterium's proteins

(Exam 1 part b: Chapter 3) In living systems, a critical component of many reactions is

water

(Exam 1 part b: Chapter 3) Oil and water do not mix well because

water is polar and oil is nonpolar

(Ch. 3) Nitrogen has 7 protons, 7 neutrons, and 7 electrons. What is the atomic number of nitrogen?

7 The atomic number is the number of protons that an atom possesses. This value may be found on the periodic table and is unique to each element.

(Ch. 4) What is the role of the Golgi apparatus?

Chemically tagging and packaging proteins The Golgi apparatus is responsible for chemically tagging and packaging proteins and sometimes lipids for transport, not only to specific locations within the cell, but at times for transport to the exterior of the cell. The ER functions in protein or lipid synthesis while the nucleus is the location of chromosomal DNA. The lysosomes are primarily responsible for the enzymatic breakdown of large molecules in the cell.

(Ch. 4) Which of the following cell structures can be found in both prokaryotes and eukaryotes?

Cytoplasm, plasma membrane, ribosomes Nuclei, the two types of ER, Golgi apparatuses, and lysosomes are found only in eukaryotic cells.

(Exam 1 part b: Chapter 3) Which of the following statements is true of proteins, carbohydrates, and nucleic acids?

Each of these molecules is built from a common set of monomers.

(Ch. 5) Which of the following is used in photosynthesis and released during cellular respiration?

H2O Both H2O and CO2 are used during photosynthesis to help make glucose and are produced during the breakdown of glucose that occurs during cellular respiration. While sunlight is used in photosynthesis, it is not involved in cellular respiration.

(Exam 1 part b: Chapter 3) The chemical reaction that represents photosynthesis is 6 H2O + 6 CO2 → C6H12O6 + 6 O2. What are the reactants?

H2O and CO2

(Exam 1 part b: Chapter 3) A carwash attendant offers to treat Martin's windshield with a protective agent. This substance coats the glass, causing beads of water to easily roll off during a rain shower. Which of the following must be correct about the protective agent?

It must be hydrophobic.

(Ch. 4) Which cellular structure is primarily responsible for water and solute storage but sometimes also stores cellular waste products?

Large central vacuole The cytoskeleton provides internal organizational and structural support for the cell. The chloroplast performs photosynthesis, while the mitochondria are responsible for cellular respiration.

(Exam 1 part b: Chapter 3) Which of the following is likely to participate in ionic bonding?

Li+

(Ch. 3) Which of the following is an ion?

Na+ The positive sodium ion, Na+, is an ion. Any atom with a charge, positive or negative, is an ion.

(Ch. 4) Which cellular structure is responsible for the localized storage of chromosomal DNA?

Nucleus The endoplasmic reticulum is involved in protein and lipid synthesis, while the lysosomes are responsible for enzymatic breakdown of large molecules. The Golgi apparatus tags proteins for transport.

(Ch. 4) ________ is a pumped-up version of endocytosis where large macromolecules, or even entire microscopic organisms, are engulfed and "eaten" by another cell.

Phagocytosis Pinocytosis refers to a form of endocytosis more closely associated with the intake of fluids and any incidental particles. Osmosis refers to the diffusion of water molecules across a selectively permeable membrane. Exocytosis is the movement of large molecules to the outside of the cell.

(Ch. 5) Which of the following statements about energy metabolism is FALSE?

Plants provide the H2O and CO2 that animals need to carry out respiration. Cellular respiration does not use H2O or CO2 as reactants; these are actually two of the products of respiration. Plants provide the glucose and O2 that make respiration possible.

(Exam 1 part b: Chapter 3) Astronauts returning from outer space studied samples taken from their lunar landing. They found that one of their samples was coated with organic compounds. Which of the following statements must be correct about their samples?

The samples must contain carbon atoms.

(Exam 1 part b: Chapter 3) Which of the following is correct about hydrogen bonds?

They form due to partial positive and partial negative charges on atoms.

(Ch. 3) The main difference between an acid and a base is that

acids donate hydrogen ions in water whereas bases accept hydrogen ions. Acids donate hydrogen ions to lower the pH of a solution, whereas bases accept hydrogen ions to raise the pH.

(Exam 1 part b: Chapter 3) A researcher in a laboratory tests a food item and identifies protein in it. The food item must also contain

amino acids.

(Exam 1 part b: Chapter 3) After adding a small amount of Solution A to Solution B, the pH of Solution B declines from 8 to 3. Solution A must contain

an acid

(Exam 1 part b: Chapter 3) Based on the figure shown below, which of the following has a lower concentration of hydrogen ions?

antacids

(Exam 1 part b: Chapter 3) The pH scale measures the

concentration of hydrogen ions in a solution.

(Exam 1 part b: Chapter 3) Carbon atoms are bound to each other by ________ bonds.

covalent

(Exam 1 part b: Chapter 3) In the chemical reaction that forms hydrogen peroxide (H2O2), hydrogen and oxygen share electrons, creating ________ bonds between the two atoms.

covalent

(Exam 1 part b: Chapter 3) Atoms in a single molecule of methane, CH4, share electrons. Methane is formed by ________ bonds joining ________ atoms.

covalent; 5

(Ch. 5) Glycolysis takes place in the ________ and produces ________, which in the presence of O2 then enters the ________.

cytoplasm; pyruvate; mitochondrion to complete cellular respiration Glycolysis is the only portion of cellular respiration that occurs outside the mitochondria. If oxygen is present, pyruvate can enter the mitochondrion to complete cellular respiration.

(Exam 1 part b: Chapter 3) You are given an unknown substance and asked to determine whether it is polar or nonpolar. The easiest way to do this would be to

determine whether the compound dissolves in water

(Exam 1 part b: Chapter 3) An acid is a polar substance that dissolves in water and

donates hydrogen ions to the solution.

(Exam 1 part b: Chapter 3) The subatomic particles that possess a single negative charge and surround the nucleus are the

electrons

(Exam 1 part b: Chapter 3) The subatomic particles that possess a single negative charge, surround the nucleus, and are lost or gained by atoms called ions are the

electrons.

(Ch. 5) One strategy that makes metabolic pathways more efficient is that

enzymes for a given pathway are located in the same place within the cell. Concentrating both substrates and enzymes in the same cellular location is one way to make metabolic pathways more efficient, as the products of one enzyme-catalyzed reaction become the reactants for the next reaction. Other ways include attaching enzymes to membranes or combining them into free-floating multienzyme complexes.

(Exam 1 part b: Chapter 3) In making her morning tea, Dorothy drops a sugar cube into some hot water. She stirs the mixture but no longer sees the sugar cube at the bottom of her mug. Based on her observation of sugar dissolving in hot water, she can properly conclude that the sugar is

hydrophilic.

(Exam 2 part a :Chapter 4) Phospholipids are large organic molecules with a hydrophilic, polar phosphate head connected to hydrophobic, nonpolar fatty acid tails. These molecules arrange themselves to form a mostly impermeable barrier between a liposome and its environment by lining up

hydrophobic tails facing each other at the center line of the membrane with the hydrophilic heads facing outward, away from the center line of the membrane.

(Exam 2 part a :Chapter 4) Dialysis tubing is a selectively permeable membrane that can be filled with a solution to simulate a cell. A piece of dialysis tubing has been filled with a cloudy white solution of 5 percent starch, 5 percent egg albumin (protein), and 5 percent glucose (a small sugar) dissolved in water to simulate a cell. This simulated cell is weighed and then placed in a beaker of water. After soaking in the water for one hour, the simulated cell is once again weighed.Over time, the weight of the simulated cell can be expected to

increase because the solution in the beaker is hypotonic to the simulated cell and water will enter the simulated cell through osmosis.

(Exam 1 part b: Chapter 3) When calcium (Ca++) and chloride (Cl−) interact with one another, they bond using ________ bonds.

ionic

(Exam 1 part b: Chapter 3) Sodium chloride (table salt) is formed when positively charged sodium ions and negatively charged chloride ions are chemically attracted to each other. This attraction is best described as a(n)

ionic bond.

(Exam 1 part a: Chapters 1 & 2) Carbon, hydrogen, and oxygen atoms are held together by chemical bonds to form ________ of sugar.

molecules

(Exam 1 part b: Chapter 3) A solution with a pH of 4 is ________ acidic than a solution with a pH of 5. The solution with the pH of 4 has a ________ concentration of hydrogen ions than the solution with a pH of 5

more; higher

(Exam 1 part b: Chapter 3) O2, also termed atmospheric oxygen, is formed by a covalent bond between two oxygen atoms. This type of bond involves oxygen atoms

sharing electrons

(Exam 2 part a :Chapter 4) If the concentration of sugar molecules in water on side "A" of a selectively permeable membrane is 5 percent, and the concentration of sugar molecules in water on side "B" of a selectively permeable membrane is 15 percent, the water will

mostly move from side "A" to side "B" because the water concentration is higher on side"A."

(Exam 2 part a :Chapter 4) Scientists repeat their experiments over and over again because they

must make sure the results were not accidents and that they are repeatable.

(Exam 2 part a :Chapter 4) Adenine (A), thymine (T), guanine (G), and cytosine (C) are the ________ building blocks for DNA; they are organized in different combinations to code for all of the proteins needed to accomplish everything the cell does.

nucleotide

(Ch. 3) Carbon can form many different kinds of complex molecules because

one carbon atom can bond with up to four other atoms, including other carbon atoms. A carbon atom has four valence electrons in its outer shell, which allows it to bond with up to four other atoms. This allows carbon to form chains and more complex, branched molecules.

(Exam 2 part a :Chapter 4) Cells naturally, without using energy, respond to changes in water concentration through the process of

osmosis

(Exam 2 part a :Chapter 4) During the process of ________, water diffuses across a semipermeable membrane from an area where water is more concentrated to an area where water is less concentrated (it moves along the water concentration gradient).

osmosis

(Exam 1 part b: Chapter 3) Neighboring water molecules are held together with hydrogen bonds because

partially negatively charged oxygen atoms and partially positively charged hydrogen atoms on separate water molecules are attracted to one another.

(Exam 2 part a :Chapter 4) Liposomes form spontaneously from ________ and are important because ________.

phospholipid bilayers; they provide a barrier between an external environment and an internal environment

(Exam 2 part a :Chapter 4) Living cells have an intact phospholipid bilayer that separates the cell from its external environment; this structure is commonly referred to as the

plasma membrane

(Ch. 4) The________ is a phospholipid bilayer that separates the internal components of a living cell from the cell's external environment.

plasma membrane While mitochondria, chloroplasts, and the nuclear envelope are enclosed by or constructed from membranes, they do not separate the entire cell from the environment.

(Exam 1 part b: Chapter 3) Hydrogen and oxygen atoms are held together within an individual water molecule by ________ bonds.

polar covalent

(Exam 1 part b: Chapter 3) The bonds connecting the atoms in the molecule below are ________ bonds

polar, covalent

(Exam 1 part b: Chapter 3) Macromolecules are typically formed by repetitively adding small monomers together. Which macromolecule is properly matched with the appropriate monomer?

polypeptide—amino acid

(Exam 2 part a :Chapter 4) Examine the figure below. Assume each sugar molecule represents a percentage point of sugar dissolved in the solution. Over time, the solution level on the left side of the figure would ________, while the solution level on the right side of the figure would ________. This is because the solution on the left side of the figure is ________, while the solution on the right side of the figure is ________.

rise; decrease; hypertonic; hypotonic

(Exam 2 part a :Chapter 4) Cheryl is in a lab attempting to prepare a slide of cow blood for observation in a wet mount. She places a small drop of the blood on a slide, adds a drop of strong saline (salt) solution, and then covers all of it with a coverslip. After returning to her desk, she observes the slide with her microscope and notices that all of the red blood cells (RBCs) do not look like the nice round donut-shaped cells in her lab manual. Instead, the RBCs look very shriveled up. Her lab partner, Derek, has also made a slide, but the RBCs on his slide do look like the ones in the lab manual. Derek used a more dilute solution of saline but the same vial of blood.The most plausible explanation for the appearance of the blood cells on Cheryl's slide is that the

saline she used was hypertonic to the RBCs; this resulted in water osmosing through the RBC plasma membrane mostly out of the cell.

(Exam 2 part a :Chapter 4) A scientist is observing a membrane through which water and some small hydrophobic molecules can freely pass along a concentration gradient from high to low. However, some sugar molecules are too large to pass through the membrane either way without the assistance of passive transport proteins. Additionally, small Na+ ions and some proteins can pass through the membrane against the concentration gradient, but both require the assistance of active transport proteins. What general type of membrane are they observing?

semipermeable

(Exam 2 part a :Chapter 4) If a bottle of perfume was spilled in the corner of a large lecture hall, the students sitting near that corner of the room would very quickly smell the perfume. Over time, the students sitting in the far corner of the room would smell the perfume. What phenomenon has occurred to the perfume molecules that have entered the air?

simple diffusion

(Ch. 4) Osmosis is a form of

simple diffusion During the process of osmosis, water molecules will move from an area where water is in greater concentration (lower solute concentration) to an area where water is at a lower concentration (higher solute concentration) until an equilibrium is reached.

(Exam 1 part b: Chapter 3) A disaccharide consists of two

sugars

(Ch. 5) The ultimate source of energy for most living systems is

sunlight Although glucose is used by cells to produce ATP, the glucose must first be made through photosynthesis. Sunlight provides the energy needed to make glucose through the process of photosynthesis. Organisms that perform photosynthesis, like plants, some bacteria, and some protozoans, can use this glucose directly, while organisms that eat photosynthesizers or other consumers get this glucose indirectly.

(Exam 2 part a :Chapter 4) The selective permeability of a phospholipid bilayer membrane can be increased with help from ________ proteins

transport proteins, channel proteins, and passive carrier