Studied by 1 personmost of a cells enzymes are
proteins
in the plasma membrane, the phospholipid heads
are both hydrophilic and face outward toward the aqueous solution on both sides of the membrane
aquaporin's
allow water to cross the plasma membrane via facilitated diffusion
kinetic energy differs from chemical energy in that
kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules
you are told that the cells on a microscope slide are plant, animal, or bacterial. you look at them through a microscope and see cell walls and membrane bound organelles. you conclude correctly that the cells
are plant cells
anything that prevents atp formation will most likely
result in cell death
which metabolic pathway is common to aerobic and anaerobic metabolism
glycolysis
in fermentation ___________ is _____________
nadh; oxidized
when a cell uses chemical energy to perform work, it uses the energy released from a(n) ____________ reaction to drive a(n) ___________ reaction
exergonic; endergonic
what is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?
rough er, golgi, vesicles that fuse with plasma membrane
the tertiary structure of a protein is the
unique three-dimensional shape of the fully folded polypeptide
which organelle or structure is absent in plant cells
centrosomes
according to the fluid mosaic model of membrane structure, proteins of the membrane are mostly
embedded in a lipid bilayer
which cell would be best for studying lysosomes
phagocytic white blood cell
which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly
CO2
which of the following is a major cause of the size limits for certain types of cells
the need for a surface area of sufficient area to support the cells metabolic needs
how many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long
10
when chemical, transport, or mechanical work is done by an organism, what happens to the heat generated
it is lost to the environment
the bonding of two amino acid molecules to form a larger molecule requires which of the following
removal of a water molecule
which level of protein structure do the helix and the beta pleated sheet represent
secondary
which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperature
the double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly
which of the following is true of both starch and cellulose
they are both polymers of glucose
which of these experimental treatments would increase the rate of sucrose transport into the cell
decreasing extracellular pH
the r group or side chain of the amino acid serine is -CH2-OH. the r group or side chain of amino acid leucine is -CH2-CH-(CH3)2. where would you expect to find these amino acids in a globular protein in aqueous solution
leucine would be in the interior, and serine would be on the exterior of the globular protein
in receptor mediated endocytosis, receptor molecules initially project to the outside of the cell. where do they end up after endocytosis
on the inside surface of the vesicle
which or the following statements correctly describes the normal tonicity conditions for typical plant and animal cells
the animal cells is in an isotonic solution, and the plant cell is in a hypotonic solution
how might an amino acid change at a site distant from the active site of the enzyme alter the enzymes substrate specifically
by changing the shape of the protein
which of the following correctly lists the order in which cellular components will be found in the pellet when homogenized cells are treated with increasingly rapid spins in a centrifuge
nucleus, mitochondria, ribosomes
enzymes that break down dan catalyze the hydrolysis of the covalent bonds that join nucleotides together. what would happen to dns molecules treated with these enzymes
the phosphodiester linkages of the polynucleotide backbone would be broken
which of the following statements about the 5' end of a polynucleotide strand of dna is correct
the 5' end has a phosphate group attached to the number 5 carbon of carbon deoxyribose
if cells are grown in a medium containing radioactive 32P labeled phosphate, which of these molecules will be labeled
both phospholipids and nucleic acids
the element present in all organic molecules is
carbon
which of the following is not a monomer/polymer pairing
triglyceride/phospholipid bilayer
which of the following is an example of potential rather than kinetic energy
a molecule of glucose
an animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function
cell-cell recognition
what is the chemical reaction mechanism by which cells make polymers from monomers
dehydration reactions
the golgi apparatus has a polarity or sidedness to its structure and function. which of the following statements correctly describes this polarity
proteins and lipids in the membrane of the golgi may be sorted and modified as they move from one side of the golgi to the other
a biologist wants specifically to examine the surface of different types of cells in kidney tubules of small mammals. the cells in question can be distinguished by external shape, size, and 3-D characteristics. which of the following would be the optimum method for her study
scanning electron microscopy
protein kinases are enzymes that catalyze phosphorylation of target proteins at specific sites, whereas protein phosphates catalyze removal of phosphate(s) from phosphorylated proteins. phosphorylation and dephospho rylation can function as an on-off switch for a proteins activity, most likely through
the change in a proteins charge leading to a conformational change
which of the following is true for all exergonic reactions
the reactions proceeds with a net release of free energy
a dietary calorie equals 1 kilocalorie. which of the following statements correctly defines 1 kilocalorie
1000 calories, or the amount of heat required to raise the temperature of 1 kg by 1C
dehydration reactions are used in forming which of the following compounds
triacylglycerides, polysaccharides, and proteins
all of the following are part of a prokaryotic cell except
a cell wall
what is another name for a condensation reaction
dehydration
what is the name of the process during which a bond between two monomers is broken
hydrolysis
nucleic acid polymers are made up of ____________ monomers
nucleotide
carbohydrate polymers are made up of _______________ monomers
simple sugar
protein polymers are made up of _____________ monomers
amino acid
which element is closely associated with the field of organic chemistry
carbon
what does the term amino acid signify about the structure of the molecule
it consists of an amino group and a carboxyl group
polymers that contain sugars ...
may store hereditary information, may store energy, and may protect cells
what one characteristic is shared by sucrose and maltose
they are disaccharides
glycogen is _____________
a polysaccharide found in animals
glucose + glucose --> _________ by _________
maltose + water ; dehydration synthesis
which of these is a source of lactose
milk
which of these is a polysaccharides
cellulose
________ is the most abundant organic compounds on earth
cellulose
lipids are diverse compounds that are grouped together because they are _________
hydrophobic
a fat molecule is composed of two typer of smaller molecules: ___________ and fatty acids
glycerol
a fatty acid consists of a ________________ and a long hydrocarbon chain
carboxyl group
________________ have one or more double bonds in their hydrocarbon chains and are usually found in vegetable oils
unsaturated fatty acids
the hydrocarbon chains of _______________ are not kinked, and thus pack closely together, making animal fats solid at room temperature
saturated fatty acids
____________ are a major component of cell membranes. they form a bilayer with their hydrophobic tails mingling together and their hydrophilic heads facing the watery environment on both sides of the membrane
phospholipids
________ are lipids with a structure consisting of four fused rings. many sex hormones are made from this type of lipid
steroids
which of these is not a lipid
RNA
which of these is rich in unsaturated fats
olive oil
a function of cholesterol that does not harm health is its role _______
as a component of animal cell membranes
the lipids that form the main structural component of cell membranes are _______
phospholipids
some athletes use anabolic steroids to build their body mass. why is this considered a problematic practice, especially in adolescents
anabolic steroids can prevent bone growth
defensive proteins are manufactured by the _______ system
immune
your body contains thousands of different types of proteins, each with a specific function. a proteins function is largely determined by its ___________
shape
the primary structure of a protein is like the arrangement of beads on a string. in this analogy, the beads are _________
amino acids
a proteins alpha helices and beta sheets form their shapes at the _______ level of protein structure
secondary
what happens to the shape and function of a protein if one of the amino acids is replaced with a different type of amino acid
it depends on the role of the amino acid that is altered. one amino acid might be replaced with no measurable effect on the proteins function; replacing another might cause a total loss of function
large proteins, like dna polymerase and hemoglobin, are often composed of several polypeptides that are linked together. the _______ level of protein structure describes how the polypeptides are joined to create a larger complex
fourth
which of these functional groups is found in all amino acids
-NH2
proteins are polymers of ________
amino acids
what type of bond joins the monomers in a proteins primary structure
peptide
the secondary structure of a protein results from __________
hydrogen bonds
tertiary structure is not directly dependent on __________
peptide bonds
which of the following would be affected when a protein is denatured
tertiary structure
if a dna double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain
75
the two strands of a dna double helix are held together by ________ that form between pairs of nitrogenous bases
hydrogen bonds
a nucleotide is composed of a(n) _________
phosphate group, a nitrogen-containing base, and a five-carbon sugar
nucleic acids are polymers of _________
nucleotides
the monomers of nucleic acids consist of phosphate group, a five carbon sugar, and a _________________
nitrogenous base
________ provides directions for its own replication. it also directs cell activities by providing instructions for building proteins
dna
a gene provides the directions to build a molecule of ________; the genetic instructions it carries are then translated into the amino acid sequence
rna
a polynucleotide has a repeating ___________ backbone
sugar-phosphate
the structure of dna is a __________, held together by the complementary base-pairing of cytosine with guanine, and adenine with thymine
double helix
ran usually consists of a single _______ strand
polynucleotide
which of the following statements regarding lactose tolerance is true
lactose tolerance has evolved independently in multiple different human population
________ are surface appendages that allow a bacterium to stick to a surface
fimbriae
what is the function of bacterium capsule
protection
where is a bacterial cells dna found
nucleoid region
in a bacterium, where are proteins synthesized
ribosomes
what name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial cell
cell wall
the ________ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell
plasma membrane
which plant cell organelle converts chemical fuel into packets of chemical energy that can power the cell
mitochondrion
the plant cell wall
is a protective structure made of cellulose fibrils
Note
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