Bio 108 Ch 3 and 5
pH=
-log[H+]
The H+ and OH- concentrations in any aqueous solution at 25 degrees celcius is____
10^-14
for a neutral aqueous solution, H+ is
10^-7 M
In a neutral solution, at room temperature (25 degrees Celcius), H+ = _____ and OH- = ______
10^-7 for both, hence H+ and OH- concentrations combined = 10^-14
What is the pH of an aqueous solution with the hydronium ion concentration [H3O+] = 2 x 10-14 M ?
13.7
How many electron pairs does carbon share in order to complete its valence shell? 1 3 8 4 2
4
most biological fluids are within the range (pH)...
6-8
10^-7 M equals ___ on the pH scale
7
Define an acid
A substance that increases the hydrogen ion concentration of a solution.
Define a base
A substance that reduces the hydrogen ion concentration of a solution.
The partial negative charge in a molecule of water occurs because A) 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. B)the oxygen atom acquires an additional electron. C)one of the hydrogen atoms donates an electron to the oxygen atom. D) the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus. E) the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms.
A) 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.
On food packages, to what does the term "insoluble fiber" refer? A) cellulose B) polypeptides C) starch D) amylopectin E) chitin
A.
Which of the following complex carbohydrates is listed with its correct function? A. Cellulose: structural component of plant cell walls B. Chitin: constituent of bacterial cell walls C. Starch: primary energy-storage molecule in animals D. Amylose: main component of plant starch
A.
Water molecules cling to plant cell walls. This is an example of?
Adhesion
Water molecules cling to the side of a beaker. This is an example of?
Adhesion
How many structural isomers are possible for a substance having the molecular formula C4H10? A) 1 B) 2 C) 4 D) 3 E) 11
B
Each water molecule is joined to _____ other water molecules by ____ bonds. a) two ... polar covalent b) four ... hydrogen c) three ... ionic d) four ... polar covalent e) two ... hydrogen
B) four....hydrogen
A fat (or triacylglycerol) would be formed as a result of a dehydration reaction between A) one molecule of 9 and three molecules of 10. B) three molecules of 9 and one molecule of 10. C) one molecule of 5 and three molecules of 9. D) three molecules of 5 and one molecule of 9. E) one molecule of 5 and three molecules of 10.
B.
Which complex carbohydrate contains only a-1,4-glycosidic linkages? A. Glycogen B. Amylose C. Amylopectin D. Cellulose
B.
Which molecule is not a carbohydrate? A. Glycogen B. Lipid C. Cellulose D. Starch
B.
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? A) Dehydration reactions can occur only after hydrolysis. B) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. C) Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable. D) Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers. E) Hydrolysis creates monomers, and dehydration reactions break down polymers.
B.
Which of the following statements about monosaccharide structure is true? A. A six-carbon sugar is called a pentose. B. Monosaccharides can be classified according to the spatial arrangement of their atoms. C. Aldoses and ketoses differ in the position of their hydroxyl groups. D. All monosaccharides contain carbon, hydrogen, oxygen, and nitrogen atoms.
B.
Why are human sex hormones considered to be lipids? A) They are essential components of cell membranes. B) They are steroids, which are not soluble in water. C) They are made of fatty acids. D) They are hydrophilic compounds. E) They contribute to atherosclerosis.
B.
what kind of amino acid is Arginine?
Basic and polar
The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius? A) 1.0°C B) 20.0°C C) 10.0°C D) 2.0°C E) 0.2°C
C) 10
Humans can digest starch but not cellulose because A) the monomer of starch is glucose, while the monomer of cellulose is galactose. B) humans have enzymes that can hydrolyze the beta glycosidic linkages of starch but not the alpha glycosidic linkages of cellulose c) humans have enzymes that can hydrolyze the alpha glycosidic linkages of starch but not the beta glycosidic linkages of cellulose D)humans harbor starch-digesting bacteria in the digestive tract E) the monomer of starch is glucose,while the monomer of cellulose is maltose
C.
The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. What is the result of adding hydrogens to vegetable oil? A. The hydrogenated vegetable oil is less likely to clog arteries. B. The hydrogenated vegetable oil has fewer trans fatty acids. C. The hydrogenated vegetable oil stays solid at room temperature. D. The hydrogenated vegetable oil has a lower melting point. E. The hydrogenated vegetable oil has more "kinks" in the fatty acid chains.
C.
Which of the following is true regarding saturated fatty acids? A) They are the predominant fatty acid in corn oil. B) Theyhave double bonds between carbon atoms of the fatty acids. C) They are the principal molecules in lard and butter. D) They are usually liquid at room temperature. E) They are usually produced by plants.
C.
A drop of water spilled on a table form a drop on the table, rather than spreading out on the surface. This is an example of?
Cohesion
The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called? A) a covalent bond B) a hydrophilic bond C) a van der Waals interaction D) a hydrogen bond E) an ionic bond
D) a hydrogen bond
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified? A) as a pentose B) as a hexose C) as a monosaccharide D) as a disaccharide E) as a polysaccharide
D.
Which modifications of fatty acids will best keep triglycerides solid at warmer temperatures? A) creating cis double bonds to the fatty acids B) adding hydrogens to the fatty acids C) creating trans double bonds to the fatty acids D) adding hydrogens and trans double bonds to the fatty acids E) adding cis double bonds and trans double bonds to the fatty acids
D.
Which of the following molecules could be joined together by a phosphodiester type of covalent bond? A) 3 and 4 B) 3 and 8 C) 6 and 15 D) 11 and 12 E) 11 and 13
D.
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by: A) hydrogen bonds. B) ionic bonds. C) van der Waals interactions. D) nonpolar covalent bonds. E) polar covalent bonds.
E) Polar covalent bonds
the pH declines as _____ concentration increases
H+
What is a buffer?
It is a substance that minimizes cahnges in the concentrations of H+ and OH- in a solution.
Which of these is rich in unsaturated fats? olive oil a fat that is solid at room temperature butter lard beef faT
OLIVE OIL
Which polysaccharide contains a modified monosaccharide? Starch Peptidoglycan Cellulose Glycogen
PEPTIDOGLYCAN
Which of these is NOT a lipid? phospholipid steroids wax cholesterol RNA
RNA
A water strider runs across a pond without breaking the surface. This is an example of?
Surface tension
True or false? Peptidoglycan is a polysaccharide found only in bacteria.
TRUE
True or false? Enzymes in the digestive tract catalyze hydrolysis reactions.
True
Rank the following from most acidic to least acidic.[H30]=-6, PH= 14, [H30]= 10^-2, PH=3, PH=5
[H30]= 10^-2, PH=3, PH=5, [H30]=-6, PH= 14
In a neutral solution the concentration of _____. A) hydrogen ions is equal to the concentration of hydroxide ions b) hydrogen ions is less than the concentration of hydroxide ions c) water molecules is less than the concentration of hydrogen ions d) water molecules is less than the concentration of hydroxide ions e) hydrogen ions is greater than the concentration of hydroxide ions
a
The tendency of an atom to pull electrons toward itself is referred to as its _____. a) electronegativity b) ionic potential c) polarity d) tonicity e) covalency
a) electronegativity
A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound? a. It should dissolve in water. b. It won't form hydrogen bonds with water. c. It lacks an asymmetric carbon, and it is probably a fat or lipid. d. It is hydrophobic. e. It should dissolve in a nonpolar solvent.
a.
Which two functional groups are always found in amino acids? a. carboxyl and amino b. carbonyl and amino c. ketone and methyl d. amino and sulfhydryl e. hydroxyl and carboxyl
a.
Why are hydrocarbons insoluble in water? a) The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages. b) They are hydrophilic. c) They exhibit considerable molecular complexity and diversity. d) The majority of their bonds are polar covalent carbon-to-hydrogen linkages. e) They are lighter than water.
a.
when acids dissolve in water they... a) donate additional H+ to the solution b) reduce the H+ concentration by accepting hydrogen bonds
a.
The complexity and variety of organic molecules is due to a) the chemical versatility of carbon atoms. b) their interaction with water. c) the variety of rare elements in organic molecules. d) their tremendously large sizes. e) the fact that they can be synthesized only in living organisms.
a. the chemical versatility of carbon atoms.
what kind of amino acid is glutamic acid?
acidic and polar
Proteins are polymers of_________
amino acids
A function of cholesterol that does not harm health is its role _____. the most abundant male sex hormone All of cholesterol's effects cause the body harm. as the primary female sex hormone as a component of animal cell membranes in calcium and phosphate metabolism
as a component of animal cell membranes
Carbonated cola is more acidic than coffee or even orange juice because cola contains phosphoric acid. What is the molar concentration of [H3O+] in a cola that has a pH of 3.120? (For help with significant figures, see Hint 3.) a) 7.58 × 10−4 b) 7.59 × 10−4 c) 7.6 × 10−4 d) 3.120 × 10−3 e) 0.494 f) 1.318 × 103
b
Which of the following statements is true about buffer solutions? a) They are found only in living systems and biological fluids. b) They maintain a relatively constant pH when either acids or bases are added to them. c) They maintain a relatively constant pH of approximately 7 when either acids or bases are added to them. d) They maintain a constant pH when acids are added to them but not when bases are added to them. e) They maintain a constant pH when bases are added to them but not when acids are added to them.
b
Which of the following statements best describes the carbon atoms present in a seed-eating bird? a) The carbon atoms ultimately came from simple organic compounds that formed abiotically from inorganic carbon, hydrogen, oxygen, and nitrogen atoms. b) The carbon atoms ultimately came from carbon dioxide incorporated into sugars through photosynthesis. c) Inorganic carbon atoms in the seeds were incorporated into organic molecules by the bird. d) The carbon atoms are ultimately derived from coal. e) The carbon atoms ultimately came from the soil.
b) The carbon atoms ultimately came from carbon dioxide incorporated into sugars through photosynthesis.
Which of the following statements correctly describes cis-trans isomers? a) Their atoms and bonds are arranged in different sequences. b) They have variations in arrangement around a double bond. c) They have different molecular formulas. d) They have an asymmetric carbon that makes them mirror images. e) They have the same chemical properties.
b) They have variations in arrangement around a double bond.
Liquid water's high specific heat is mainly a consequence of the a) fact that water is a poor heat conductor. b) absorption and release of heat when hydrogen bonds break and form. c) high specific heat of oxygen and hydrogen atoms. d) small size of the water molecules. e) higher density of liquid water than solid water (ice).
b) absorption and release of heat when hydrogen bonds break and form.
Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that a. exist in either linear chain or ring forms. b. are mirror images of one another. c. differ in the arrangement of atoms around their double bonds. d. differ in the location of their double bonds. e. have identical chemical formulas but differ in the branching of their carbon skeletons.
b.
When Stanley Miller applied heat and electrical sparks to a mixture of simple inorganic compounds such as methane, hydrogen gas, ammonia, and water vapor, what compounds were produced? a) mostly hydrocarbons b) both simple organic compounds and more complex organic compounds such as amino acids and hydrocarbons c) only simple inorganic compounds d) only simple organic compounds such as formaldehyde and cyanide e) mostly amino acids
b.
Which monomers make up RNA? a. Polymers b. Nucleotides c. Simple sugars d. Amino acids
b.
Which polymers are composed of amino acids? a. Nucleic acids b. Proteins c. Monomers d. Carbohydrates
b.
Buffers are substances that help resist shifts in pH by a) releasing to a solution when bases are added. b) both donating to a solution when bases are added, and accepting H+ when acids are added. c) releasing to a solution when acids are added. d) donating to a solution when bases are added. e) accepting from a solution when acids are added.
b. both donating to a solution when bases are added, and accepting H+ when acids are added
what kind of amino acid is lysine?
basic and polar
Solutions with a higher concentration of OH- than H+ are known as
basic solutions
One mole (mol) of glucose (molecular mass = 180 daltons) is a) the largest amount of glucose that can be dissolved in 1 L of solution. b) 180 kilograms of glucose. c) both 180 grams of glucose and 6.02 × 1023 molecules of glucose. d) 180 × 1023 molecules of glucose. e) 1 kg of glucose dissolved in 1 L of solution.
c) both 180 grams of glucose and 6.02 × 1023 molecules of glucose.
In animal metabolism, most of the monomers released by digestion of food macromolecules are metabolized to provide energy. Only a small portion of these monomers are used for synthesis of new macromolecules. The net result is that a. water is consumed during homeostasis, but water is generated during periods of growth. b. water is generated during homeostasis, but water is consumed during periods of growth. c. water is consumed by animal metabolism. d. the water consumed is exactly balanced by the water generated, to maintain homeostasis. e. water is generated by animal metabolism.
c.
Which of the following is not attached to the central carbon atom in an amino acid? a. An amino functional group b. A carboxyl functional group c. An oxygen d. A side chain ("R group")
c.
Buffers that contribute to pH stability in human blood are...
carbonic acid (formed when CO2 reacts with water in blood plasma). This buffer can respond to both a rise and drop in pH, switching between carbonic acid and bicarbonate.
Water molecules are attracted to each other. This is an example of?
cohesion
How many molecules of glucose ( molecular mass = 180 daltons) would be present in 90 grams of glucose? a) (6.02/180) × 10^23 b) (90 x 6.02) × 10^23 c) (6.02/90) × 10^23 d) (90/180) × 6.02 × 10^23 e) 90 × 10^23
d
How many molecules of glycerol (; molecular mass = 92) would be present in 1 L of a 1 M glycerol solution? a) 92 × 6.02 × 10^23 b) 14 × 6.02 × 10^23 c) 1 × 10^6 d) 6.02 × 10^23 e) 6.02 × 10^26
d
The element present in all organic molecules is a) oxygen. b) phosphorus. c) hydrogen. d) carbon. e) nitrogen.
d) carbon
Which type of bond must be broken for water to vaporize? a) ionic bonds b) both hydrogen bonds and ionic bonds c) both polar covalent bonds and hydrogen bonds d) hydrogen bonds e) polar covalent bonds
d) hydrogen bonds
Hydrophobic substances such as vegetable oil are a) polar substances that have an affinity for water. b) polar substances that repel water molecules. c) nonpolar substances that have an attraction for water molecules. d) nonpolar substances that repel water molecules. e) charged molecules that hydrogen-bond with water molecules.
d) nonpolar substances that repel water molecules.
The unequal sharing of electrons within a water molecule makes the water molecule _____. a) have a low surface tension b) ionic c) hydrophobic d) polar e) change easily from a liquid to gaseous form
d) polar
Compared to a hydrocarbon chain where all the carbon atoms are linked by single bonds, a hydrocarbon chain with the same number of carbon atoms, but with one or more double bonds, will a. be more flexible in structure. b. have more hydrogen atoms. c. have fewer structurally distinct isomers. d. be more constrained in structure. e. be more polar.
d.
The molar mass of glucose () is 180 g/mol. Which of the following procedures should you carry out to make a 0.5 M solution of glucose? The molar mass of glucose () is 180 g/mol. a) Dissolve 0.5 g of glucose in 1 L of water. b) Dissolve 180 g of glucose in 0.5 L of water. c) Dissolve 0.5 g of glucose in a small volume of water, and then add more water until the total volume of solution is 1 L. d) Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L. e) Dissolve 180 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L.
d.
Which of the following statements about the formation of polypeptides from amino acids is true? a. The reaction occurs through the addition of a water molecule to the amino acids. b. A bond can form between any carbon and nitrogen atom in the two amino acids being joined. c. Polypeptides form by condensation or hydrolysis reactions. d. A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.
d.
Which part of an amino acid is always acidic? a. None of the above b. Side chain ("R group") c. Amino functional group d. Carboxyl functional group
d.
A strong acid like HCL... a) reacts with strong bases to create a buffered solution. b) is a strong buffer at low pH. c) increases the pH when added to an aqueous solution. d) both ionizes completely in aqueous solutions and is a strong buffer at low pH. e) ionizes completely in an aqueous solution.
e.
The secondary structure of a protein results from ____
hydrogen bonds
Which type of interaction stabilizes the alpha helix and the beta pleated sheet structure of proteins A)hydrophobic interactions B)non polar covalent bonds C) Ionic Bonds D) hydrogen bonds E) peptide bonds
hydrogen bonds
major ingredients of cell membranes are _____ so the membranes won't dissolve into water.
hydrophobic
A solution in which the H+ and OH- concentrations are equal is
neutral
what kind of amino acid is Asparagine?
neutral and non polar
what kind of amino acid is methionine?
neutral and non polar
what kind of amino acid is phenylalanine?
neutral and non polar
what kind of amino acid is tryptophan?
neutral and non polar
what kind of amino acid is Cysteine?
neutral and polar
what kind of amino acid is glutamine?
neutral and polar
what kind of amino acid is serine?
neutral and polar
what kind of amino acid is tyrosine?
neutral and polar
what kind of amino acid is threonine?
neutral and slightly polar
what kind of amino acid is proline?
neutral non polar
what kind of amino acid is valine?
neutral non polar
what kind of amino acid is Alanine?
non polar and neutral
Hydrophobic substances are _____ and _______
nonionic and nonpolar
When CO2 dissolves in seawater, if reacts to form carbonic acid, which lowers pH. This process is know as
ocean acidification
What type of bond joins the monomers in a protein's primary structure?
peptide
Tertiary structure is NOT directly dependent on ________ hydrophobic interactions ionic bonds hydrogen bonds peptide bonds bonds between sulfur atoms
peptide bonds
H+ and OH- are very _____ a) acidic b) reactive c) ionic
reactive
The alpha helix and beta pleated sheet represent which level of protein structure?
secondary
when compounds dissociate completely when mixed with water, the result is a _______ acid or base. a) weak b) neutral c) strong
strong
A needle floats when it is placed gently on top of water in a bucket. This is an example of?
surface tension
_____________ structure is the result of two or more protein sub units assembling to form a larger, biologically active protein complex
tertiary?
a dalton is equal to....
the atomic mass of a molecule, which is equal to 1 mol, which is equal to 6.022 X 10^23 particles. ***(not sure if this is right)***
molarity equals...
the number of moles solute per liter of solution (equal levels of concentration)
