Download BY 123 SI Mock Exam #1 Chapters 1

BY 123 SI
Mock Exam #1
Chapters 1-7
1) A sodium ion (Na+) contains 10 electrons, 11 protons, and 12 neutrons. What is the atomic number
of sodium?
a. 10
b. 11
c. 24
d. 23
2) What is the atomic mass of 147𝑁 ?
a. 7
b. 10
c. 14
d. 46
3) Which of the following describes what happens as a chlorophyll pigment absorbs energy from
sunlight?
a. An electron moves to a higher electron shell and the electron’s potential energy increases.
b. An electron moves to a higher electron shell and its potential energy decreases.
c. An electron drops to a lower shell and its potential energy decreases.
d. An electron of sunlight is transferred to chlorophyll, producing a chlorophyll ion with higher potential
energy.
4) The ability of morphine to mimic the effects of the body’s endorphins is due to:
a. a chemical equilibrium developing between morphine and endorphins.
b. the one-way conversion of morphine into endorphin.
c. molecular shape similarities that allow morphine to bind to endorphin receptors.
d. hydrogen bonding and other weak bonds forming between morphine and endorphins.
5) When water boils, which bonds are breaking?
a. polar covalent bonds
b. ionic bonds
c. hydrogen bonds
d. non polar covalent bonds
6) Which bonds are IN water molecules?
a. polar covalent bonds
b. ionic bonds
c. hydrogen bonds
d. non polar covalent bonds
7) What accounts for the movement of water up the vessels of a tree?
a. cohesion
b. adhesion
c. hydrogen bonding
d. hydrophilic cell walls
e. all of the above
8) Ice floats because:
a. air is trapped in the crystalline lattice
b. the formation of hydrogen bonds releases heat; warmer objects always float
c. its surface area is smaller
d. hydrogen bonding spaces the molecules apart, creating a less dense structure.
9) The molarity of a solution is equal to:
a. Avogadro’s number of molecules in 1 liter of solvent
b. the number of moles of a solute in 1 liter of solvent
c. the molecular mass of a solute in 1 liter of solution
10) Adding a base to a solution would:
a. raise the pH
b. lower the pH
c. decrease [H+]
d. Both a and c
11) Some archaea are able to live in lakes with pH values of 11. How does pH 11 compare with the pH 7
typical of the human body?
a. It is four times more basic
b. It is 1,000 times more basic
c. It is 10,000 times more basic
d. It is 4 units more acidic.
12) Hydrocarbons are not soluble in water because:
a. they are fats and are hydrophilic
b. The Carbon and Hydrogen bonds are nonpolar
c. they do not ionize
d. they are lighter than water
13) The fats stored in your body consist mostly of
a. alcohols
b. methyl groups
c. hydrocarbons
d. organic phosphates
14) Which of the following does not match its description?
a. phosphate – forms bonds that stabilize protein structure
b. hydroxyl and carbonyl—components of sugars
c. methyl—its addition changes the shape and function of certain molecules
d. amino and carboxyl—components of amino acids.
15) The chemical group that gives acidic properties to organic molecules is:
a. –SH
b. OH
c. –COOH
d. NH2
16) The chemical group that can cause an organic molecule to act as a base is:
a. –OH
b. –SH
c. –COOH
d. –NH2
17) Polymerization is a process that:
a. creates bonds between amino acids in the formation of a polypeptide.
b. involves the removal of a water molecule
c. links the sugar of one nucleotide with the phosphate of the next
d. involves a dehydration reaction
e. may involve all of the above
18) Disaccharides can differ from each other in all of the following ways EXCEPT:
a. in the number of their monosaccharides
b. in their structural formulas
c. in the monomers involved
d. in the location of their glycosidic linkage
e. They can differ in all of these
19) Plants store most of their energy for later use as
a. unsaturated fats
b. glycogen
c. starch
d. sucrose
e. cellulose
20) A cow can derive nutrients from cellulose because
a. it can produce the enzymes that break down the Beta linkages between glucose molecules
b. it chews and rechews its cud so that cellulose fibers are finally broken down
c. its rumen contains prokaryotes that can hydrolyze the bonds of cellulose
d. its intestinal tract contains termites, which harbor microbes that hydrolyze cellulose
e. it can convert cellulose to starch and then hydrolyze starch to glucose
21) Which of the following substances is the major component of the cell membrane of fungus?
a. cellulose
b. chitin
c. cholesterol
d. phospholipids
e. unsaturated fatty acids
22) A fatty acid that has the formula C16H32O2 is
a. saturated
b. unsaturated
c. branched
d. hydrophilic
e. part of a steroid molecule
23) In a fat molecule, you would find ____ glycerol molecule bound to 3 _______ ______.
a. 2, oxygen atoms
b. 1 , unsaturated fats
c. 1, fatty acids
d. 1, saturated fats
e. 2, carboxylic acid
#24) Which of the following is NOT one of the many functions performed by proteins?
a.
b.
c.
d.
e.
Acting as signals and receptors
Acting as an enzymatic catalyst for metabolic reactions
Providing protection against disease
Serving as contractile components of muscle
Forming primary structural component of membranes
#25) What happens when a protein denatures?
a.
b.
c.
d.
e.
Its primary structure is disrupted
Its secondary and tertiary structures are disrupted
It always flips inside out
It hydrolyzes into component amino acids
Its hydrogen bonds, ionic bonds, hydrophobic interactions, disulfide bridges, and peptide bonds
are disrupted
#26) What determines the sequence of the amino acids in a particular protein?
a. Its primary structure
b. The sequence of nucleotides in RNA, which was determined by the sequence of nucleotides in
the gene for that protein
c. The sequence of nucleotides in DNA, which was determined by the sequence of nucleotides in
RNA
d. The sequence of RNA nucleotides making up the ribosome
e. The three-dimensional shape of the protein
#27) How are nucleotide monomers connected to form a polynucleotide?
a. By hydrogen bonds between complementary nitrogenous base pairs
b. By ionic attractions between phosphate groups
c. By disulfide bridges between cysteines
d. By covalent bonds between the sugar of one nucleotide and the phosphate of the next
e. By ester linkages between the carboxyl group of one nucleotide and the hydroxyl group on the
ribose of the next.
#28) Which of the following is/ are NOT found in a prokaryotic cell?
a.
b.
c.
d.
e.
Ribosomes
Plasma membrane
Mitochondria
A and C
A, B, and C
#29) Proteins that function within the cytosol are generally synthesized :
a.
b.
c.
d.
e.
By ribosomes bound to rough ER
By free ribosomes
By the nucleolus
Within the Golgi apparatus
By mitochondria and chloroplasts
#30) The pores in the nuclear envelope provide for the movement of:
a.
b.
c.
d.
e.
Proteins into the nucleus
Ribosomal subunits out of the nucleus
mRNA out of the nucleus
signal molecules into the nucleus
all of the above
#31) A fluorescent green tag is attached to a protein being synthesized and inserted into an area of
rough ER membrane. Which of the following is a possible route for that protein to follow?
a.
b.
c.
d.
e.
Rough ER  Golgi  lysosome  nuclear membrane  plasma membrane
Rough ER  transport vesicle  Golgi  vesicle  plasma membrane  food vacuole
Rough ER  nuclear envelope  Golgi  smooth ER  lysosome
Rough ER  transport vesicle  Golgi  smooth ER  plasma membrane
Rough ER  transport vesicle  Golgi  vesicle  extracellular matrix
#32) Which of the following is NOT a similarity among nuclei, chloroplasts, and mitochondria?
a. They contain DNA
b. They are bound by two (or more) phospholipid bilayer membranes
c. They can divide to reproduce themselves
d. They are derived from the endoplasmic reticulum system
e. Their membranes are associated with specific proteins
#33) Microtubules are components of all of the following EXCEPT:
a.
b.
c.
d.
e.
Centrioles
The spindle apparatus for separating chromosomes in cell division
Tracks along which organelles can move using motor proteins
Flagella and cilia
The cleavage furrow that pinches apart cells in animal cell division
#34) The innermost portion of the cell wall of a plant cell specialized for support is the :
a.
b.
c.
d.
e.
Primary cell wall
Secondary cell wall
Middle lamella
Plasma membrane
Cytoskeleton
#35) Plasmodesmata in plant cells are similar in function to :
a.
b.
c.
d.
e.
Desmosomes
Tight junctions
Gap junctions
The extracellular matrix
Integrins
#36) Which of the following is INCORRECTLY paired with its function?
a.
b.
c.
d.
e.
Peroxisome—contins enzymes that break down H2O2
Nucleolus—produces ribosomal RNA, assembles ribosome subunits
Golgi apparatus—processes, tags, and ships cellular products
Lysosome—food sac formed by phagocytosis
ECM (extracellular matrix) –supports and anchors cells, communicates information with inside
of cell
#37) If a single layer of phospholipids coats the water in a beaker, which parts of the molecules face the
air?
a.
b.
c.
d.
e.
The phosphate groups
The hydrocarbon tails
Both heads and tails because the molecules are amphipathic and lie sideways
The glycolipid regions
No parts of the molecules face the air, because the phospholipids dissolve in the water and do
not form a layer
#38) Glycoproteins and glycolipids are important for:
a.
b.
c.
d.
e.
Facilitated diffusion
Active transport
Cell-cell recognition
Intercellular joining
Signal-transduction pathways
#39) The fluidity of membranes in a plant in cold weather may be maintained by increasing the:
a.
b.
c.
d.
e.
Proportion of peripheral proteins
Action of an H+ pumo
Concentration of cholesterol in the membrane
Number of phospholipids with unsaturated hydrocarbon tails
Number of phospholipids with saturated hydrocarbon tails
Use the following information to answer questions 40-42.
The solutions in the two arms of a tube are separated by a membrane that is permeable to water and
glucose but not to sucrose. Side A is filled with a solution of 2.0 M sucrose and 1.0 M glucose. Side B is
filled with 1.0 M sucrose and 2.0 M glucose.
#40) Initially, the solution in side A, with respect to that in side B,
a.
b.
c.
d.
e.
Has a lower solute concentration
Has a higher solute concentration
Has an equal solute concentration
Is lower in the tube
Is higher in the tube
#41) During the period BEFORE equilibrium is reached, which molecule(s) will show net movement
through the membrane?
a.
b.
c.
d.
Water
Glucose
Sucrose
Water and sucrose
e. Water and glucose
#42) AFTER the system reaches equilibrium, what changes can be observed?
a.
b.
c.
d.
e.
The water level is higher in side A than in side B
The water level is higher in side B than in side A
The molarity of glucose is higher in side A than in side B
The molarity of sucrose has increased in side A
Both a and c have occurred
#43) An animal cell placed in a hypotonic environment will:
a.
b.
c.
d.
e.
Become flaccid
Become turgid
Burst
Plasmolyze
Shrivel
#44) You observe plant cells under a microscope as they are placed in an unknown solution. First the
cells plasmolyze; after a minute, the plasmolysis reverses and the cells appear normal. What would you
conclude about the unknown solution?
a.
b.
c.
d.
e.
It is hypertonic to the plant cells, and its solute cannot cross the plant cell membranes
It is hypotonic to the plant cells, and its solute cannot cross the plant cell membranes
It is isotonic to the plant cells, but its solute can cross the plant cell membranes
It is hypertonic to the plant cells, but its solute can cross the plant cell membranes
It is hypotonic to the plant cells, but its solute can cross the plant cell membranes
#45) Which of the following is NOT true about osmosis?
a.
b.
c.
d.
e.
It is a passive process in cells without walls, but an active one in cells with walls.
Water moves into a cell from a hypotonic environment
Solute molecules bind to water and decrease the free water available to move
It can occur more rapidly through channel proteins known as aquaporins
There is no net osmosis when cells are in isotonic solutions.
#46) Facilitated diffusion of ions across a cellular membrane requires ________; and the ions move
________.
a.
b.
c.
d.
e.
Energy and channel proteins; against their electrochemical gradient
Energy and channel proteins; against their concentration gradient
Cotransport proteins; against their electrochemical gradient
Channel proteins; down their electrochemical gradient
Channel proteins; down their concentration gradient
#47) Which of the following describes cotransport?
a.
b.
c.
d.
e.
Active transport of two solutes through a cotransport protein
Passive transport of two solutes through a cotransport protein
Ion diffusion against electrochemical gradient created by an electrogenic pump
A pump such as the sodium-potassium pump that moves ions in two different directions
Transport of one solute against its concentration gradient in tandem with another that is
diffusing down its concentration gradient
#48) The proton pump in plant cells is the functional equivalent of an animal cell’s:
a.
b.
c.
d.
e.
Cotransport mechanism
Sodium-potassium pump
Contractile vacuole for osmoregulation
Receptor-mediated endocytosis of cholesterol
ATP pump