Biology Test 2
the smooth endoplasmic reticulum:
synthesizes lipids
According to the fluid mosaic model, membranes consist of?
A fluid phospholipid bilayer in which proteins are embedded.
A cell moves particles from a region of lesser concentration to a region of greater concentration by_______.
Active transport
Particle movement from an area of lower concentration to an area of higher concentration
Active transport
which scientist first viewed living cells?
Anton van Leeuwenhoek
which of the following is NOT a characteristic of facilitated diffusion? A. It requires a carrier protein B. It moves substances against a concentration gradient C. It requires no energy input D. It involves a change in the shape of its carrier
B. It moves substances against a concentration gradient
Which of the following would occur to a plant if it were placed in a 75% sugar solution? A. Undergo hemolysis B. Undergo plasmolysis C. Become turgid D. nothing E. Undergo Endocytosis
B. It would undergo plasmolysis
Transport protein that changes shape when a particle binds with it
Carrier protein
Which of the following correctly describes active transport?
Carrier proteins are needed , it requires an expenditure of energy, & molecules move from an area of high to low concentration
Transport protein that provides a tube-like opening in the plasma membrane through which particles can diffuse
Channel Protein
Junctions that permit the transfer of water, ions and molecules between cells are
Desmosomes
Which of the following does NOT expand energy? A. Diffusion B. Endocytosis C. Active transport D. A sodium potassium pump
Diffusion
Molecules that are too large to be moved through the membrane can be transported into the cell by
Endocytosis
Process by which a cell takes in material by forming a vacuole around it
Endocytosis
Which of the following is NOT a form of passive transport? A. Facilitated diffusion B. Endocytosis C. Simple diffusion D. Osmosis
Endocytosis
Is used during active transport but not passive transport
Energy
By what process do cells transport wastes from within the cell to the external environment?
Exocytosis
Molecules that are too large to be moved across a cell membrane can be removed from the cell by
Exocytosis
Process by which a cell expels wastes from a vacuole
Exocytosis
Ridding the cell of material by discharging it from sacs at the cell surface is called?
Exocytosis
A form of passive transport that uses transport proteins
Facilitated diffusion
The technique most commonly used to study the interior of a biomembrane is known as A) transmission electron microscopy. B) differential diffusion C) freeze-fracture electron microscopy. D) scanning electron microscopy.
Freeze fracture electron microscopy
A person's blood type is determined by the presence of particular ________ in the red blood cells' membranes.
Glycoproteins
The ________ can be considered a sorting, processing and packaging center.
Golgi complex
Water moves out of a cell if the cell is placed in a(n) _____ solution.
Hypertonic
Water moves into a cell if the cell is placed in a ____________ solution.
Hypotonic
Which of the following is true of facilitated diffusion? A. It occurs with a concentration gradient and requires transport proteins. B. It occurs against a concentration gradient and requires transport proteins. C. It occurs with a concentration gradient and does not require transport proteins. D. It occurs against a concentration gradient and does not require transport proteins.
It occurs with a concentration gradient and requires transport proteins.
which of the following is NOT a function of the plasma membrane?
Manufactures proteins
If a cell is placed in salt water, water leaves the cell by
Osmosis
The process by which water passes into or out of a cell is called ?
Osmosis
If cells are placed in a strong sugar solution, water will
Pass from the cells to the sugar solutions
Particle movement from an area of higher concentration to an area of lower concentration
Passive transport
By what process do cells transport small dissolved particles from external environment?
Pinocytosis
The structure most responsible for maintaining cell homeostasis is the ________.
Plasma membrane
the primary difference between the amino acids commonly found in proteins is in their:
R or variable groups
which of the following elements is NOT responsible for a significant portion of the mass of living organisms
S
a laboratory technician accidentally places red blood cells in a hypertonic solution. What will happen?
They come dehydrated and shrunken
You are conducting osmosis experiments with a test tube of human cells in solution. You add a teaspoon of table salt to the test tube. According to the principles of osmosis, what can you predict will happen to the cells?
They will shrink and shrivel.
Anchoring junctions that hold cells together at one point as a spot weld does are?
Tight junctions
junctions that help form the blood-brain barrier are?
Tight junctions
Beaker A contains a 25% salt solution. A differentially permeable bag (permeable to water, but not salt) containing 57% salt solution is allowed to float on top of the solution in Beaker A. What will occur?
Water will flow from Beaker A into the bag.
If atom X contains 14 protons, 13 electrons, and 12 neutrons, and atom Y contains 14 protons, 14 electrons, and 12 neutrons, then you conclude that:
X and Y are atoms of the same element
It is advantageous for cells to be small because:
a small cell has a small volume relative to surface area, thereby increasing efficient transport
the cis face of the golgi complex is most directly involved in which of the following? a. packaging molecules in vesicles b. accepting vesicles from the ER c. synthesizing proteins d. transporting molecules out of the golgi e. catalyzing the efficient folding of proteins
accepting vesicles from the ER
a stalk of celery is placed in a solution of blue colored dye. after one hour, the leaves have blue fluid in their veins. which property of water is being demonstrated?
adhesion and cohesion
the difference between an electrically neutral atom and an ion is that:
an ion has an unequal number of protons and electrons, while an atom has an equal number
carbohydrate molecules:
are a source of energy
one difference between tight junctions and dermatomes is that tight junctions
are regions where the plasma membrane from 2 neighboring cells are in actual contact
which of the following is a key component of the cytoskeleton? a. centrosome b. microtubules c. DNA d. ribosomes e. endoplasmic reticulum
b. microtubules
which of the following are forms of carrier-mediated transport? a. facilitated diffusion b. carrier-mediated active transport only c. osmosis only d. both facilitated diffusion and carrier mediated active transport
both facilitated diffusion an d carrier mediated active transport
which of the following are forms of carrier-mediated transport? a. facilitated diffusion only b. carrier-mediated active transport only c. osmosis only d. both facilitated diffusion and carrier-mediated active transport
both facilitated diffusion and carrier-mediated active transport
receptor-mediated endocytosis
brings about the selective uptake of materials by enclosing them in membranous vesicles
When plant cells are in a hypotonic medium, they?
build up turgor pressure
an element is defined as a substance that:
cannot be broken into simpler substances by chemical reactions
which of the following is not a property of carbon? a. carbon-to-carbon bonds are limited to single bonds b. carbon has four valence electrons c. carbon can form bonds to various other atoms d. two carbon atoms can share three electrons pairs with each other e. carbon-to-carbon bonds are strong
carbon-to-carbon bonds are limited to single bonds
which of these terms is most inclusive? a. monosaccharide b. starch c. polysaccharide d. disaccharide e. carbohydrate
carbonhydrate
Placing a plant into a hypertonic environment will
cause turgor pressure to decrease
which of the following pairs is correctly matched? a. chloroplast- storage of enzymes b. lysosome- powerhouse of the cell c. centrosome- cell divison d. plastids- structural support of the cell e. golgi complex- production of energy
centrosome- cell division
a cellular structure found in plant but not animal cells is the:
chloroplast
the theory that chloroplasts and mitochondria had their evolutionary beginnings in eukaryotic cells as endosymbionts is supported by all of the following EXCEPT:
chloroplasts and mitochondria are completely autonomous within eukaryotic cells
________________ is the form of DNA when the cell is not dividing.
chromatin
a glycoprotein destined for secretion from the cell would move through the Golgi complex in this sequence
cis face to medial region to trans face
Diffusion continues until there is no
concentration gradient
Diffusion continues until there is no _________.
concentration gradient
a chemical reaction in which polymers are synthesized from their building blocks is called:
condensation
an organic compound differs from an inorganic compound in that an organic compound:
contains carbon
which of the following is NOT a cell covering or part of a cell covering?
cristae
one function of peroxisomes involves the process of:
detoxification
the dispersal of ink in a beaker of water is an example of?
diffusion
what conditions might cause a cell to burst?
dissolved water molecules in the circle of h2o
how is facilitated diffusion powered?
energy is required to do the work of establishing and maintaining a concentration gradient
Transmembrane proteins
extend completely through the membrane
Sugar molecules can enter cells through the process of
facilitated diffusion
which of the following requires a transport protein?
facilitated diffusion
evaporative cooling is a process whereby __________ moving _________ molecules vaporize, thus ______ large amounts of heat.
fast; water; removing
An atom has six protons and eight neutrons. Its atomic mass is __________ atomic mass units.
fourteen
The technique most commonly used to study the interior of a biomembrane is known as A) transmission electron microscopy. B) fluorescence microscopy. C) freeze-fracture electron microscopy. D) scanning electron microscopy. E) fluorescence recovery after photo bleaching.
freeze-fracture electron microscopy
Diffusion takes place
from an area of high concentration to an area of low concentration
Heart cells are able to contract in unison because of the flow of ions through _____.
gap junctions
plasmodesmata of plant cells are functionally equivalent to _________ of animal cells.
gap junctions
in a chemical reaction, the product is:
generally written on the right side and is the substance generated by the reaction
the scanning electron microscope differs from the transmission electron microscope in that the scanning electron microscope:
gives a three dimensional image of the object being studied
a carbohydrate energy storage molecule found in animal liver and muscle cells is:
glycogen
what is the organelle responsible for storing, processing, and packaging products for export form the cell?
golgi complex
a eukaryotic cell:
has a variety of membrane bound organelles
solutions that are isotonic
have equal concentrations of solute and water
a patient who has had a severe hemorrhage accidentally receives a large transfusion of distilled water directly into a major blood vessel. you would expect this mistake to:
have serious, perhaps fatal consequences because the red blood cells could swell and burst
the covalent bond between a hydrogen atom and the oxygen atom in water is formed when:
hydrogen and oxygen share an electron pair
The cohesiveness between water molecules is due largely to:
hydrogen bonds
if the concentration of solutes in a cell is less than the concentration of solutes in the surrounding fluid, then the extracellular fluid is said to be:
hypertonic
if the concentration of solutes in a cell is less than the concentration of solutes in the surrounding fluid, then the extracellular fluid is said to be?
hypertonic
a wilted flower placed in a vase of water for several hours became stiff and stood erect. when it was placed in a salt solution, it wilted. from this info we can say that the cells of the flower are?
hypertonic to fresh water but hypotonic to the salt solution
Any chemical interaction between atoms:
involves only valence electrons
Pinocytosis
is the nonspecific uptake of fluids by pinching inward of the plasma membrane
sodium-potassium is?
it transports 3 sodium ions out of the cell in exchange for 2 potassium ions
the higher the concentration of solute in a solution _____, the ________ the effective water concentration and the ________ the osmotic pressure.
lower; higher
the higher the concentration of solute in a solution, the _________ the effective water concentration and the _________ the osmotic pressure.
lower; higher
the ratio of the size of the image seen with the microscope to the actual size of the object size of the object is called:
magnification
a covalent bond:
may be polar or nonpolar depending on the atoms involved
which of the following organelles plays an important role in apoptosis, or programmed cell death? a. ribosomes b. mitochondria c. chloroplasts d. vacuoles e. peroxisomes
mitochondria
Isotopes differ from each other with respect to the number of:
neutrons only
covalently bonded atoms with similar electronic negativies are:
nonpolar
The tails of phospholipids are:
nonpolar, hydrophobic, directed inwards in the bilayer
When a nucleic acid undergoes hydrolysis, the resulting subunits are:
nucleotides
The chemical behavior of an atom is determined by
number of valence electrons
facilitated diffusion
occurs with a concentration gradient and requires transport proteins
electron microscopes have a much higher resolution than either the human eye or any light microscope because:
of the very short (nanometer) wavelengths of electrons
by what process do cells transport small dissolved particles from external environments?
pinocytosis
Chlorine has seven electrons in its valence shell. The number of electrons it must gain to complete its valence shell is:
one
what membrane activities does not require the expenditure of energy by the cell?
osmosis
in a water molecule, because oxygen is more electronegative than hydrogen, the shared electrons are more commonly found around the _______ nucleus than the _________nucleus.
oxygen;hydrogen
A human white blood cell engulfs a bacterial cell by:
phagocytosis
A plasma membrane is composed primarily of?
phospholipids
The sodium-potassium pump usually pumps
potassium into the cell
at which level of protein structure are peptide bonds most important?
primary
If a toxin, such as a bacterial toxin, destroys ribosomes, what cellular activity will be affected first?
protein synthesis
which of the following statements is true of proteins? a. proteins lose some or all of their normal activity if their three-dimensional structure is disrupted b. proteins are composed of ribose, phosphate, and a nitrogen containing base
proteins lose some or all of their normal activity if their three-dimensional structure is disrupted
the particular type of element is determined by the number of:
protons
facilitated diffusion
requires a transmembrane protein
the nucleolus is responsible for making ___________.
ribosomes
which covalent bond involves only 2 electrons:
single
which of the following descriptions or structures does NOT match the cell type? a. sperm cells have flagella b. nerve cells have long, thin extensions c. epithelial cells are rectangular d. white blood cells can change shape e. smallest cell are egg cells
smallest cell are egg cells
In the formation of common table salt, sodium and chlorine interact because
sodium donates one elctron to chlorine
In a mixture, which would be present in the least amount?
solute
all of the following functions are performed by plant vacuoles EXCEPT: a. maintaining hydrostatic (turgor) pressure b. waste storage and recycling c. storage of proteins d. breakdown of unneeded cellular materials e. storage of nucleic acids
storage of nucleic acids
studies of glucose transport in liposomes have revealed that:
the binding of glucose triggers a conformational change in the carrier protein
when a chemical reaction is at equilibrium:
the forward and reverse reactions are proceeding at equal rates
a person has a genetic disease that prevents the phospholipids in the plasma membrane of the white blood cells from freely fusing with the other membranes within the cell. how would this disease affect phagocytosis?
the phagocytic vacuole would not fuse with the lysosome
the difference between a stable isotope and a radioisotope is that:
the radioisotope emits radiation
which of the following illustrates hydrolysis? a. the reaction of 2 monosaccharides to form a disaccharide b. the reaction of 2 amino acids to form a dipeptide c. the reaction of a hydrogen atom and a hydroxide ion to form water d. the reaction of a fat to form glycerol and fatty acids e. the formation of ATP and ADP and inorganic phosphate
the reaction of a fat to form glycerol and fatty acids
which of the following statements concerning centrioles is FALSE? a. they are present in most animal cells but not most plant cells b. they are duplicated before cell divison c. they have a 9 + 2 arrangement of mircrotubules d. they are found in the centrosome
they have a 9 + 2 arrangement of microtubules
you are conducting osmosis experiments with a test tube of human cells in solution. you add a teaspoon of table salt to the test tube. according to the principles of osmosis, what can you predict will happen to the cells?
they will shrink and shrivel
nucleic acid
transmits heredity information
a plant placed in a hypertonic solution will:
undergo plasmolysis
which of the following choices correctly identifies a reactant in the following chemical equation? Co2 + H2o = H2co3
water
