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Bio Exam 1
Question | Answer |
---|---|
What defines the atomic number of an element? | total number of protons in an atom |
What defines the atomic mass (weight)? | calculated mean of the mass number for an element's isotopes |
If an atom gains or loses one or more electrons to another atom, does its atomic number change? Why or why not? | No because electrons have almost no mass; they don't contribute to the mass of an atom |
nonpolar covalent bond | type of covalent bond that forms between atoms when electrons are shared equally between them |
polar covalent bond | type of covalent bond that forms as a result of unequal electron sharing, resulting in creating slightly positive and negative charged molecule regions |
hydrogen bonds | weak bond between hydrogen atoms and electronegative atoms in other molecules |
ionic bond | chemical bond that forms between ions with opposite charges (cations and anions) e.g. bonding between a metal and nonmetal element |
polarity | molecule has both a positively & negatively charged end; more important, the polarity of water is responsible for effectively dissolving other polar molecules, such as sugars and ionic compounds such as salt |
cohesion | intermolecular forces between water molecules caused by the polar nature of water; responsible for surface tension |
adhesion | attraction between water molecules and other molecules |
specific heat | the amount of heat one gram of a substance must absorb or lose to change its temperature by one degree Celsius |
heat of vaporization | high amount of energy required for liquid water to turn into water vapor |
trace element | Small amounts of metallic elements aka micronutrients |
isotope | one or more forms of an element that have different numbers of neutrons |
the three main types of isomers | chain isomers, functional group isomers and positional isomers |
If a polymer has 10 monomers, how many hydrolysis reactions would be required to completely break it down into individual monomers? | 9 |
hydrolysis, which of the four major categories of macromolecules does this apply to, and how? | reaction that causes breakdown of larger molecules into smaller molecules by utilizing water |
dehydration synthesis, which of the four major categories of macromolecules does this apply to, and how? | (also, condensation) reaction that links monomer molecules, releasing a water molecule for each bond formed; proteins, lipids (fatty acids), nucleic acids (DNA and RNA), and carbohydrates |
molarity | number of moles of solute per liter of solution |
pH | scale ranging from zero to 14 that is inversely proportional to the hydrogen ions' concentration in a solution; |
What is the maximum number of electrons that the first shell of an atom can contain? What about the higher level shells? | 2; 8; 32 |
ion | atom or chemical group that does not contain equal numbers of protons and electrons |
carbonyl | chemically organic functional group composed of a carbon atom double-bonded to an oxygen atom |
carboxyl | a combination of two functional groups attached to a single carbon atom, namely, hydroxyl (single-bonded OH) and carbonyl (double bonded O) groups |
the functions of the rough endoplasmic reticulum | region of the endoplasmic reticulum that is studded with ribosomes and engages in protein modification and phospholipid synthesis |
the functions of the smooth endoplasmic reticulum | region of the endoplasmic reticulum that has few or no ribosomes on its cytoplasmic surface and synthesizes carbohydrates, lipids, and steroid hormones; detoxifies certain chemicals (like pesticides, preservatives, medications, and environmental pollutant |
What is the role of the central vacuole in a plant cell, and how does it affect water balance with respect to external and internal conditions, and availability of water? | large plant cell organelle that regulates the cell's storage compartment, holds water, and plays a significant role in cell growth as the site of macromolecule degradation |
saturated fat/oil | long-chain hydrocarbon with single covalent bonds in the carbon chain; the number of hydrogen atoms attached to the carbon skeleton is maximized |
unsaturated fat/oil | long-chain hydrocarbon that has one or more double bonds in the hydrocarbon chain |
genome | total genetic information of a cell or organism |
chromatin | protein-DNA complex that serves as the chromosomes' building material |
chromosome | structure within the nucleus that comprises chromatin that contains DNA, the hereditary material |
buffer | substance that prevents a change in pH by absorbing or releasing hydrogen or hydroxide ions |
How does the carbonic acid system maintain constant pH in our blood? | When bicarbonate ions combine w/ free H ions & become carbonic acid, it removes H ions & moderates pH changes; excess carbonic acid can convert to CO2 gas |
A solution has a pH of 2. Is it acidic or basic? Why? | acidic because lower pH means more acidic and higher pH means basic |
What is a ribosome made of? Does it have a membrane? What does it do? | 2 pts: large & small subunit, mRNA sits in btwn them; no membrane; cellular structure that carries out protein synthesis |
What are the three major Domains of Life? | Bacteria, Archaea, and Eukarya |
Golgi apparatus | eukaryotic organelle comprised of a series of stacked membranes that sorts, tags, and packages lipids and proteins for distribution |
True or false: cholesterol is a toxic substance that should be completely removed from our bodies. Why or why not? | no, it is necessary for the body's proper functioning |
True or False: Plasma (cell) membranes are selectively permeable. Explain to someone else what selectively permeable means. | True; it chooses what it wants in and what it wants out |
What is an electrochemical gradient? How does this relate to the sodium-potassium pump? | a combined electrical and chemical force that produces a gradient; Na&K pump maintain the gradient |
receptor-mediated endocytosis | variation of endocytosis that involves using specific binding proteins in the plasma membrane for specific molecules or particles, and clathrin-coated pits that become clathrin-coated vesicles |
exocytosis | process of passing bulk material out of a cell |
osmosis | transport of water through a semipermeable membrane according to the water's concentration gradient across the membrane that results from the presence of solute that cannot pass through the membrane |
passive diffusion | passive transport process of low-molecular weight material according to its concentration gradient |
facilitated diffusion | materials diffuse across the plasma membrane with the help of membrane proteins |
primary active transport | active transport that moves ions or small molecules across a membrane and may create a difference in charge across that membrane |
secondary active transport | movement of material that results from primary active transport to the electrochemical gradient |
fluid mosaic | describes the plasma membrane's structure as a mosaic of components including phospholipids, cholesterol, proteins, glycoproteins, and glycolipids (sugar chains attached to proteins or lipids, respectively), resulting in a fluid character (fluidity) |
mitochondria | (singular = mitochondrion) cellular organelles responsible for carrying out cellular respiration, resulting in producing ATP, the cell's main energy-carrying molecule |
chloroplasts | plant cell organelle that carries out photosynthesis |
Why is it that elements in the far right column of the Periodic Table do not react chemically with atoms of other elements? | They're inert (noble) gases, they have complete valence shells |
True or false: all cells (prokaryotic and eukaryotic) have a nucleus and other membrane-bounded organelles. | false |
True or false: all cells (prokaryotic and eukaryotic) have plasma (cell) membranes. | true |
True or false: all cells (prokaryotic and eukaryotic) have cell walls. | false |
True or false: all cells (prokaryotic and eukaryotic) have ribosomes. | true |
What does it mean to say that the two strands of a DNA molecule are antiparallel to each other? What do 5’ and 3’ mean? | they grow in opposite directions; the 5th & 3rd carbon atoms in the deoxyribose/ribose sugar ring |
What is cellulose made of, and where would you find it? Can humans digest it? | polysaccharide that comprises the plants' cell wall; provides structural support to the cell; humans cannot digest |
starch | storage carbohydrate in plants |
glycogen | storage carbohydrate in animals |
microtubules | the cytoskeleton system's widest element; helps the cell resist compression, provides a track along which vesicles move through the cell, pulls replicated chromosomes to opposite ends of a÷ cell, is the structural element of centrioles, flagella, & cilia |
In DNA and RNA, which nucleotides are the purines and which are the pyrimidines? | purine: adenine & guanine. pyrimidine: thymine & uracil |
transcription | process through which messenger RNA forms from a DNA template |
translation | process through which RNA directs the protein's formation |
DNA | double-helical molecule that carries the cell's hereditary information |
RNA | single-stranded, often internally base paired, molecule that is involved in protein synthesis |
amino acids | a protein's monomer; has a central carbon or alpha carbon to which an amino group, a carboxyl group, a hydrogen, and an R group or side chain is attached; the R group is different for all 20 common amino acids |
lipids | macromolecule that is nonpolar and insoluble in water |
phospholipids | membranes' major constituent; comprised of two fatty acids and a phosphate-containing group attached to a glycerol backbone |
plasma (cell) membranes | phospholipid bilayer with embedded (integral) or attached (peripheral) proteins, and separates the cell's internal content from its surrounding environment |
anion | negative ion formed by an atom gaining one or more electrons |
balanced chemical equation | statement of a chemical reaction with the number of each type of atom equalized for both the products and reactants |
base | molecule that donates hydroxide ions or otherwise binds excess hydrogen ions and decreases the hydrogen ions' concentration in a solution |
calorie | amount of heat required to change the temperature of one gram of water by one degree Celsius |
capillary action | occurs because water molecules are attracted to charges on the inner surfaces of narrow tubular structures such as glass tubes, drawing the water molecules to the tubes' sides |
cation | positive ion formed by an atom losing one or more electrons |
chemical bond | interaction between two or more of the same or different atoms that results in forming molecules |
chemical reaction | process leading to rearranging atoms in molecules through either bond forming or breaking |
chemical reactivity | the ability to combine and to chemically bond with each other |
compound | substance composed of molecules consisting of atoms of at least two different elements |
covalent bond | type of strong bond formed between two atoms of the same or different elements; forms when electrons are shared between atoms |
dissociation | release of an ion from a molecule resulting in an ion and the charged remains of the original molecule, such as when water dissociates into H+ and OH- |
electron | negatively charged subatomic particle that resides outside of the nucleus in the electron orbital; lacks functional mass and has a negative charge of -1 unit |
electron configuration | arrangement of electrons in an atom's electron shell |
electron transfer | movement of electrons from one element to another; important in creating ionic bonds |
electronegativity | ability to attract electrons (often of hydrogen atoms), acquiring partial negative charges in molecules and creating partial positive charges on the hydrogen atoms |
element | one of 118 unique substances that cannot break down into smaller substances; each element has unique properties and a specified number of protons |
enantiomers | molecules that share overall structure and bonding patterns, but differ in how the atoms are three-dimensionally placed such that they are mirror images of each other |
equilibrium | steady state of relative reactant and product concentration in reversible chemical reactions in a closed system; often denoted in a chemical equation using double-headed arrow evaporation change from liquid to gaseous state at a body of water's surface |
functional group | group of atoms that provides or imparts a specific function to a carbon skeleton |
geometric isomer | isomer with similar bonding patterns differing in the placement of atoms alongside a double covalent bond |
hydrocarbon | molecule that consists only of carbon and hydrogen |
hydrophilic | describes ions or polar molecules that interact well with other polar molecules such as water |
hydrophobic | describes uncharged nonpolar molecules that do not interact well with polar molecules such as water |
inert gas | (also, noble gas) element with filled outer electron shell that is unreactive with other atoms |
irreversible chemical reaction | chemical reaction where reactants proceed unidirectionally to form products |
isomers | molecules that differ from one another even though they share the same chemical formula |
law of mass action | chemical law stating that the rate of a reaction is proportional to the concentration of the reacting substances |
mass number | total number of protons and neutrons in an atom |
matter | anything that has mass and occupies space |
molecule | two or more atoms chemically bonded together |
neutron | uncharged particle that resides in an atom's nucleus; has a mass of one amu |
nucleus | core or center of an atom; contains protons and neutrons |
octet rule | rule that atoms are most stable when they hold eight electrons in their outermost shells |
organic molecule | any molecule containing carbon (except carbon dioxide) |
periodic table | organizational chart of elements indicating each element's atomic number and atomic mass; provides key information about the elements' properties |
product | molecule that is a result of chemical reaction; usually found on the right side of a chemical equation |
proton | positively charged particle that resides in the atom's nucleus; has a mass of one amu and a charge of +1 |
radioisotope | isotope that emits radiation comprised of subatomic particles to form more stable elements |
reactant | molecule that takes part in a chemical reaction; usually found on the left side of chemical equation |
reversible chemical reaction | chemical reaction that functions bidirectionally, where products may turn into reactants if their concentration is great enough |
solvent | substance capable of dissolving another substance |
sphere of hydration | when a polar water molecule surrounds charged or polar molecules thus keeping them dissolved and in solution |
structural isomers | molecules that share a chemical formula but differ in the placement of their chemical bonds |
surface tension | tension at the surface of a body of liquid that prevents the molecules from separating; created by the attractive cohesive forces between the liquid's molecules |
valence shell | outermost shell of an atom |
van der Waals interaction | very weak interaction between molecules due to temporary charges attracting atoms that are very close together |
Integral protein | protein integrated into the membrane structure that interacts extensively with the membrane lipids' hydrocarbon chains and often spans the membrane |
Peripheral protein | protein at the plasma membrane's surface either on its exterior or interior side |
What does it mean when a solution has more H+? | It's more acidic |
Hypotonic | situation in which extracellular fluid has a lower osmolarity than the fluid inside the cell, resulting in water moving into the cell |
Endocytosis | aka phagocytosis; type of active transport that moves substances, including fluids and particles, into a cell |
Pinocytosis | a variation of endocytosis that imports macromolecules that the cell needs from the extracellular fluida variation of endocytosis that imports macromolecules that the cell needs from the extracellular fluid |
Hypertonic | situation in which extracellular fluid has a higher osmolarity than the fluid inside the cell, resulting in water moving out of the cell |
isotonic | Extracellular fluid has the same osmalarity as the fluid inside the cell, resulting in no net movement into or out of the cell |
evaporation | change from liquid to gaseous state at a body of water's surface |
alpha-helix structure (a-helix) | type of secondary protein structure formed by folding the polypeptide into a helix shape with hydrogen bonds stabilizing the structure |
beta-pleated sheet (ß-pleated) | secondary structure in proteins in which hydrogen bonding forms "pleats" between atoms on the polypeptide chain's backbone |
biological macromolecule | large molecule necessary for life that is built from smaller organic molecules |
carbohydrate | biological macromolecule in which the ratio of carbon to hydrogen and to oxygen is 1:2:1; serve as energy sources |
chitin | type of carbohydrate that forms the outer skeleton of all arthropods that include crustaceans and insects; it also forms fungi cell walls |
denaturation | loss of shape in a protein as a result of changes in temperature, pH, or chemical exposure |
disaccharide | two sugar monomers that a glycosidic bond links |
enzyme | catalyst in a biochemical reaction that is usually a complex or conjugated protein |
glycosidic bond | bond formed by a dehydration reaction between two monosaccharides with eliminating a water molecule |
hormone | chemical signaling molecule, usually protein or steroid, secreted by endocrine cells that act to control or regulate specific physiological processes |
messenger RNA (mRNA) | RNA that carries information from DNA to ribosomes during protein synthesis monomer smallest unit of larger molecules that are polymers |
monosaccharide | single unit or monomer of carbohydrates |
nucleic acid | biological macromolecule that carries the cell's genetic blueprint and carries instructions for the cell's functioning |
nucleotide | monomer of nucleic acids; contains a pentose sugar, one or more phosphate groups, and a nitrogenous base |
omega fat | type of polyunsaturated fat that the body requires; numbering the carbon omega starts from the methyl end or the end that is farthest from the carboxylic end |
peptide bond | bond formed between two amino acids by a dehydration reaction |
phosphodiester | linkage covalent chemical bond that holds together the polynucleotide chains with a phosphate group linking neighboring nucleotides' two pentose sugars |
polymer | chain of monomer residues linked by covalent bonds; polymerization is the process of polymer formation from monomers by condensation |
polynucleotide | long chain of nucleotides |
polypeptide | long chain of amino acids linked by peptide bonds |
protein | biological macromolecule comprised of one or more amino acid chains |
primary structure | linear sequence of amino acids in a protein |
polysaccharide | long chain of monosaccharides; may be branched or unbranched |
quaternary structure | association of discrete polypeptide subunits in a protein |
ribosomal RNA (rRNA) | RNA that ensures the proper alignment of the mRNA and the ribosomes during protein synthesis and catalyzes forming the peptide linkage |
secondary structure | regular structure that proteins form by intramolecular hydrogen bonding between the oxygen atom of one amino acid residue and the hydrogen attached to the nitrogen atom of another amino acid residue |
steroid | type of lipid comprised of four fused hydrocarbon rings forming a planar structure |
trans fat | fat formed artificially by hydrogenating oils, leading to a different arrangement of double bond(s) than those in naturally occurring lipids |
tertiary structure | a protein's three-dimensional conformation, including interactions between secondary structural elements; formed from interactions between amino acid side chains |
transfer RNA (tRNA) | RNA that carries activated amino acids to the site of protein synthesis on the ribosome |
triacylglycerol (also, triglyceride) | fat molecule; consists of three fatty acids linked to a glycerol molecule |
wax | lipid comprised of a long-chain fatty acid that is esterified to a long-chain alcohol; serves as a protective coating on some feathers, aquatic mammal fur, and leaves |
The central rule of molecular biology states that ________. | DNA is transcribed into RNA, which is translated into protein |
If one strand of a DNA molecule has the sequence of bases 5′-ATTGCA-3′, the mRNA synthesized following the template will be ________. | 3′-UAACGU-5′ |
You disrupt all hydrogen bonds in a protein. What level of structure will be preserved? | primary structure |
What component of amino acid structure varies among different amino acids? | the components of the R group |
What are the monomers of proteins? | Amino acids |
What is the sum total of all the chemical reactions that take place in your body called? | Metabolism |
What is another name for the polymers of carbohydrates? | Polysaccharides |
What is the basic structure of most lipids? | A glycerol head and up to three fatty acid tails |
Which the following best summarizes the relationship between dehydration reactions and hydrolysis? | Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart. |
Phospholipids and triglycerides both ________. | have glycerol |
How many molecules of water are released during the polymerization of a 20 monomer-long cellulose molecule? | 19 |
Which of the following dietary fats is considered to be the least healthy? | Trans fat |
People who are lactose intolerant cannot extract energy from milk because ________. | they are missing an enzyme |
Which would have the highest concentration of C—H bonds? | Saturated fat |
In carbohydrates, the ratio of hydrogen (H) to oxygen (O) is ________. | 2:1 |
Which of the following is not a polymer? | glucose |
What will be accomplished by lowering the activation energy of a reaction? | The reaction will proceed more quickly. |
Enzymes are a type of ________. | protein |
What kind of bond joins amino acids together to form a protein? | Peptide bond |
Proteins are diverse molecules that perform a wide variety of functions. Which of the following is not a typical function of proteins? | Energy storage |
The left to right order of elements in the periodic table is based on their ________. | atomic number |
What is the pH of a solution with a hydroxyl ion (OH-) concentration of 10^-10 M? | pH 4 |
A solution contains 0.0000001 (10^-7) moles of hydrogen ions [H+] per liter. Which of the following best describes this solution? | neutral |
Atoms have no electric charge because they have ________. | an equal number of protons and electrons |
Oxygen has an atomic number of 8 and, most commonly, a mass number of 16. Thus, what is the atomic mass of an oxygen atom? | approximately 16 daltons |
A salamander relies on hydrogen bonding to stick to various surfaces. Therefore, a salamander would have the greatest difficulty clinging to a ________. | surface of hydrocarbons |
Bonds between two atoms that are equally electronegative are ________. | nonpolar covalent bonds |
The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride? | MgCl2 |
How many electron pairs are shared between the carbon atoms in a molecule that has the formula C2H4? | two |
Van der Waals interactions may result when ________. | electrons are not symmetrically distributed in a molecule |
What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms? | six |
Refer to the following figure to answer the questions below. 3H2 + N2 ⇌ 2NH3 Which of the following factors will increase the rate of reaction in the forward direction? | addition of both nitrogen and hydrogen |
Which of the following correctly describes chemical equilibrium? | Forward and reverse reactions continue with no net effect on the concentrations of the reactants and products. |
The atomic number of nitrogen is 7. Nitrogen-15 has a greater mass number than nitrogen-14 because the atomic nucleus of nitrogen-15 contains ________. | 8 neutrons |
A neutral atom has two, eight, and eight electrons in its first, second, and third energy levels. This information ________. | does not tell us about the atomic mass of the element |
Why are hydrocarbons insoluble in water? | The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages. |
What is the difference between covalent bonds and ionic bonds? | Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms. |
The partial negative charge in a molecule of water occurs because ________. | the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus |
Which of the following statements is true about buffer solutions? | They maintain a relatively constant pH when either acids or bases are added to them. |
cell wall | rigid cell covering comprised of various molecules that protects the cell, provides structural support, and gives shape to the cell |
centrosome | region in animal cells made of two centrioles that serves as an organizing center for microtubules |
chlorophyll | green pigment that captures the light energy that drives the light reactions of photosynthesis |
cilium (plural = cilia) | short, hair-like structure that extends from the plasma membrane in large numbers and functions to move an entire cell or move substances along the cell's outer surface |
flagellum | (plural = flagella) long, hair-like structure that extends from the plasma membrane and moves the cell |
eukaryotic cell | cell that has a membrane-bound nucleus and several other membrane-bound compartments or sacs |
endoplasmic reticulum (ER) | series of interconnected membranous structures within eukaryotic cells that collectively modify proteins and synthesize lipids |
cytoplasm | entire region between the plasma membrane and the nuclear envelope, consisting of organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals |
cytoskeleton | protein fiber network that collectively maintains the cell's shape, secures some organelles in specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently |
cytosol | the cytoplasm's gel-like material in which cell structures are suspended |
electron microscope | an instrument that magnifies an object using an electron beam that passes and bends through a lens system to visualize a specimen |
endomembrane system | group of organelles and membranes in eukaryotic cells that work together modifying, packaging, and transporting lipids and proteins |
intermediate filament | cytoskeletal component, comprised of several fibrous protein intertwined strands, that bears tension, supports cell-cell junctions, and anchors cells to extracellular structures |
microfilament | the cytoskeleton system's narrowest element; it provides rigidity and shape to the cell and enables cellular movements |
lysosome | organelle in an animal cell that functions as the cell's digestive component; it breaks down proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles |
nuclear envelope | double-membrane structure that constitutes the nucleus' outermost portion |
nucleoplasm | semi-solid fluid inside the nucleus that contains the chromatin and nucleolus |
nucleolus | darkly staining body within the nucleus that is responsible for assembling ribosome subunits |
nucleoid | central part of a prokaryotic cell's central part where the chromosome is located |
organelle | compartment or sac within a cell |
peroxisome | small, round organelle that contains hydrogen peroxide, oxidizes fatty acids and amino acids, and detoxifies many poisons |
unified cell theory | a biological concept that states that one or more cells comprise all organisms; the cell is the basic unit of life; and new cells arise from existing cells |
vacuole | membrane-bound sac, somewhat larger than a vesicle, which functions in cellular storage and transport |
vesicle | small, membrane-bound sac that functions in cellular storage and transport; its membrane is capable of fusing with the plasma membrane and the membranes of the endoplasmic reticulum and Golgi apparatus |
How does the carbonic acid system maintain constant pH in our blood? Pt 2 | this prevents too many free H ions from building up in the blood & dangerously reducing the blood’s pH; if too much OH– enters into the system, carbonic acid will combine with it to create bicarbonate, lowering the pH |