binds substrates in a manner that facilitates the formation of product
Enzyme
Which of the following is an enzyme?
Carboxypeptidase
A sick person often has a fever, which can inhibit the growth of bacteria because?
enzymes don't function as well at temperatures other than the optimal temperature
The equation AB+H20 A+B would be catalyzed by which of the following classes of enzymes
hydrolases
An allosteric inhibitor
binds at the regulatory site
A competitive inhibitor
cannot be processed as a substrate by the enzyme
A prosthetic group in an enzyme
is located in the reaction center, assists in catalysis
An increase in temperature activates chemical reactions by?
increasing the number of molecules with energy high enough to undergo the reaction
Catalyst is an agent that?
enhances the rate of the reaction
Aspirin binds to the prostaglandin synthetase and permanently stops its ability to produce prostaglandin. This is an example of?
Irreversible inhabition
Fireflies have the ability to convert the energy in ATP to light. Which of the following types of work is performed
bioluminescent
Nerve impulses travel along the neurons by the opening of channels that allow sodium ions to flow inward, followed by an outward flow of potassium ions. In order to ensure that the impulse may be produced at any time, sodium is actively transported out of
concentration
The statement, the total amount of energy in the universe is constant,
is a tenet of the first law of thermodynamics
Negative free energy change indicates that?
the reaction is exergonic
Aerobic refers to what property of chemotrophs?
requires oxygen to produce energy
CO2 generally enters the plant through pores called?
Stomata
in chloroplast, the stroma, is the?
central semifluid region
which statement accurately describes the Calvin cycle?
carbon fixation, CO2 is reduced to organic sugars, occurs in chloroplast stroma, a carbon assimilation process
the calvin cycle occurs in the ?
Stroma
in the Calvin cycle, the enzyme that catalyzes the capture of carbon dioxide and the formation of 3-phosphoglycerate
ribulose bisphosphate caboxylase/ oxygenase (rubisco)
biosynthesis of sucrose occurs in the?
cytoplasm
breakdown of glucose to pyruvate by a cell is an example of?
catabolic
negatively charged phosphates of ATP influence one another by?
charge repulsion
gross output of ATP from glycolysis is 4, where as the net output of ATP is ?
2
during strenuous exercise, you may notice your muscles burn
w/o Oxygen, pyruvate is being converted to lactic acid
energy in the cell can be stored by accumulating reduced compounds because?
reduction reactions are endergonic, oxidation reactions are exergonic
phosphate cleavage of starch or glycogen polymers involves?
using phosphate to break the bond between monomers
products of glycolysis are?
ATP, NADH, Pyruvate
in aerobic conditions, pyruvate generated during glycolysis is converted to?
acetyl CoA and used in aerobic respiration
Gluconeogenesis occurs in the
liver
Is not a production of the TCA cycle?
acetyl CoA
Would not be used as a final electron acceptor in anaerobic respiration
oxygen
Resting potential of a particular nerve cell is -66mV. Depolarization of the membrane will shift the membrane potential toward
0 mV
based on graph, what period of time sodium channels start to inactivate
1msec
graph above, what point in the action potential does repolarization
C
graph above, at the same time that stimulus was introduced, a drug that specifically inhibits sodium channels was added to the system. Effect this would have is that the membrane would
not depolarize
the knee-jerk reflex circuit includes activation of the following neurons
sensory, interneuron, and motor innervating the extensor muscle
structure of an ion channel, the gate and the selectivity filter
can be different parts of the channel molecule
your record amplitudes of 0,2,6,8 pA in a single channel experiment. How many channels are in this patch
2
the order of events in an action potential is
activation of sodium channels, activation of voltage-gated potassium channels, inactivation of sodium channels, closing of voltage-gated K+ channels
the main differences between electrical and chemical synapse are?
electrical is faster and bidirectional
signaling distance is increasing in the following order
synaptic, paracrine, endocrine signaling
Transport systems involved in maintaining low calcium ion concentration in the cytoplasm are
ER Calcium pump, plasma membrane calcium pump, and calcium/sodium exchanger
Nitric Oxide signaling is involved in regulation of?
smooth muscle relaxation
Not a function of cytoskeleton
passive transport
Correct sequence of microtubule assembly
tubulin dimers, oligomers, protofilaments, sheets of protofilaments, closing of microtubule, elongating microtubule
Not a function associated with the cytoskeleton
anchoring site for mRNA during transcription
Striated muscle has?
light (I-bands) and dark bands (A-bands).
What takes place as muscle contracts?
I band gets smaller, H zones get smaller, Z lines get closer together
In relaxed muscle, calcium is found in high concentration in the?
sacroplasmic reticulum
when glucose is converted to glucose-6-phosphate by hexokinase, the accumulation of glucose-6-phosphate inhibits the reaction
Feedback inhibition
A foreign substance is added to the reaction in part a above. The substance binds to the hexokinase and prevents its ability to catalyze the reaction
non-competitive inhibition
An inactive form of an enzyme becomes active after being phosphorylated
covalent
An increase in temperature activates chemical reactions by
increasing the number of molecules with energy high enough to undergo the reaction
Which type of microscope has the greatest resolving power?
electron
Single channel recording is a
technique that allows to measure electrical currents through a single ion channel molecule
The movement of water through a membrane from an area of high concentration to an area of low concentration is known as
osmosis
Cellulose is a polymer of _____, a common monosaccharide.
glucose
While fishing, a biology student makes the following observations: 1) water spiders may be walking on water, 2) flat rocks may be made to skip across the water. Which of the following properties of water can explain these observations?
Water molecules are associated via hydrogen bonds
The rate of facilitated diffusion is limited predominantly?
the number of transport proteins in the membrane
Which of the following is true of a nanometer?
A nanometer is one millionth of a meter
Which of the following is NOT a function of membranes?
Information storage
The two most important properties that allow a molecule to cross a phospholipid simple diffusion are?
polarity and size
Which of the following biological polymer is mismatched with its monosaccharide?
Cellulose-fatty acid
Why can't Glucose cross the lipid bilayer?
Because it is too large
The polarity of water is caused by the _______.
unequal sharing of electrons between oxygen and hydrogen atoms.
Substances that can readily pass through the cell membrane are chemically ______ by nature.
non-polar
CFTR belongs to?
ABC transporters
Which is the strongest of the following forces that stabilize protein structure in solution?
Covalent Bonds
V-type ATPase
pumps protons into vesicles
Which of the following is the smallest?
Proteins
One of the strategies for a single cell to increase its membrane transport efficiency is ?
cytoplasmic streaming
You are designing a protein that will transport potassium into the cell which protein will it be?
ATPase
Biologically, which of the following is the least important characteristics?
Water typically contains isotopes of hydrogen
Ribosomes that do not anchor to the surface of the rough endoplasmic reticulum during translation most probably are?
synthesizing cytoplasmic proteins
The hydropathy plot of a protein shows four hydrophobic regions. Which protein is true?
The protein has four hydrophobic domains
Which of the following is a disaccharide?
Lactose
The main differences between plant and animal cells are?
chloroplasts, vacuoles, and cell wall
The transport of two molecules across the cell membrane in opposite direction is called?
Antiport
A voltage-gated calcium-activated chloride channel is activated by?
membrane voltage and calcium conducts chloride
Which of the following is NOT a tenet of the cell theory?
All cells have a membrane bound nucleus
1 m=
1,000,000nm
1nm=
1/1000000
Cellulose belongs to which of the following groups of macromolecule?
Polysaccharide
________ are liquid at room temperature, while __________ are solid.
Unsaturated fatty acids , saturated fatty acids
Which of the following can ONLY be viewed by electron microscopy?
Viruses
Diffusion is a trans membrane movement of a substance with the concentration gradient, with?
no involvement of membrane proteins
Trypsin is a hydrophilic protease enzyme and cannot cross the plasma membrane. It can however, cut the hydrophilic parts of the proteins that are exposed to the extracellular environment. When the cells are treated with trypsin, in how many fragments will
4
Sedimentation coefficient is?
a ratio between the velocity of the particle and the acceleration during centrifugation
Cells of the pancreas produce and directly release enzymes of the digestive system. The type of secretory mechanism associated with the pancreatic cells is?
regulated secretion
Which of the following organelles are not part of the endomembrane system?
mitochondria
Smooth ER functions in drug detoxification process by?
adding hydrophobic residue to hydrophilic drugs
Transport of vesicles from plasma membrane to Golgi to ER is called?
retrograde transport
Clathrin lattice assembly is similar to?
soccer ball
Endocytosis involves?
invagination of the plasma membrane, trapping particles and internalizing
Rough ER is involved in?
protein synthesis and cotranslational insertion, protein maturation, removal of misfolded proteins (all of the above)
Which of the following statements is false regarding phagocytosis?
It involves the projection of pseudopodia
A protein is destined to be secreted from a cell in which of the following you expect to find the protein first?
Golgi apparatus
Which of the following cell junctions are associated with the proper alignment of epithelial cells?
(all of the above) gap junctions, tight junctions,desmosomes, adhesive junctions
Which of the following is NOT associated with the adhesive junctions?
Plaques or connexin
Heterotypic interactions of the cell adhesion proteins involve?
the different proteins from different cells
You are studying the effects of calcium influx on vesicle release. If channel blocker, you would expect?
No release
Tight junction is mostly permeable to?
Cations
With regard to the semi-permeable nature of the plasma membrane, which of the following would readily cross it without the aid of a transport protein?
Water
Transmembrane movement of a substance along its concentration gradient is?
Active transport
The cells with the largest single dimension in our bodies are?
Oocytes
A scientist is examining motile protozoa. He wishes to determine their direction of movement. Which of the following microscopic techniques is LEAST likely to be used to view these cells?
Electron Microscopy
The isotonic medium
has the same concentration of solutes as the cell.
During receptor-mediated endocytosis, the ultimate fate of the vesicle and/or its contents include(s)?
Transport to late endosome for digestion, transcytosis, recycling of receptors (choice A,B, and C)
Based on your knowledge of the chemistry of the cell membrane, which of the following compounds would you couple with a new drug in order to achieve better uptake by the cells?
Lipids
Collagens are associated with which of the following types of cellular junctions?
None of Above
Which of the following is NOT soluble in water?
Lipids
Ion channels participate in what type of membrane transport?
Facilitated diffusion
Which of the following sequences correctly lists the hierarchical nature of cellular structure from smallest to largest?
Small molecules, macromolecules, macromolecule complexes, organelles.
Why is a selectively permeable membrane so important to living cells?
It provides a good barrier between the inside and the outside of the cell
Cystic fibrosis is the result of malfunction of the cell in transporting which of the ions?
Cl-
You have genetically engineered a yeast cell to make a protein that will ultimate secreted from the cell. If all is functioning well, in which order (first to last) find the protein in the cell until it is secreted?
ER-Golgi-secretory vesicle-environment
The energy for loading a neurotransmitter into a secretory vesicle?
A proton gradient established by the proton pump on the (second choice b)
Interphase is?
a growing phase between cell divison
Mitotic index is?
% of cells in interphase
A decision to divide again or arrest & terminally differentiate is taken during the following period in the cell cycle
G1
The mitotic index of cells in a certain tissue is usually around 3-5%. You take a sample of the tissue & determine the mitotic index is 20%. What do you think is happening?
There's a possibility of tumor developing.
Chromosomes are attached to the mitotic spindle
by the kinetochore & by the connection in the centromere region
The correct stages of mitosis is?
Prophase, Metaphase, Anaphase, & Telophase
The amount of DNA a zygote gets from an egg & sperm is?
More from an egg
In asexual reproduction, progeny
can be identical to the parent
Advantages of sexual reproduction include the following
beneficial traits can be combined, beneficial mutations can be combined, & genes' reshuffling is possible
An organism has 2 copies of each of the homologs chromosomes, this organism is?
Diploid
An organism shows a dominant trait. It's genotype for this trait can be?
YY, Yy
Meiosis involves the following # of cell divisions
2
Crossing over occurs in?
Prophase I of meiosis
An example of purine is?
Guanine
DNA isolates from aspergills has adenine content of 25%. Based upon this info, what is the % of G-C w/in the Asperigills DNA?
50%
Which of the following are components of Chargaff's rule of bases?
(C+T=A+G,); A=T; purines = pyrimidines, G=C
The normal gene for hemoglobin was isolated, cloned and subjected to restriction enzyme digestion w/ BAM HI. Following gel electrophoresis, 3 bands are routinely obtained. However, following the same procedure w/ the hemoglobin gene from an individual wit
Mutation associated with sickle cell anemia results in the gain a Bam HI cut site.
The phase of the cell cycle associated with the doubling of the amount of DNA in the cell?
S phase
The difference btwn RNA & DNA involves different?
nucleotide composition, backbone sugar, single & double stranded structure
Okazaki fragments are part of the synthesis of the?
DNA lagging strand
How many pieces of double stranded DNA will you have after 2 cycle of PCR if you start with 2?
8
DNA replication is initiated by the synthesis of a?
RNA primer
DNA damage may include
Deamination, depurination, thymine dimer formation
Genetic code is degenerate because?
a given amino acid can be encoded by more than 1 nucleotide triplet
Which DNA mutation are more devastating: single, double, triple?
Depends on the location of mutation
Griffin's experiment on bacterial transformation, showed that?
Bacteria can take up DNA molecules from the enviroment
UV light treated bacteria would most likely have DNA damage in the form of?
Pyrimidine dimer formation
The longest phase of the cell cycle is?
Interphase
During metaphase in mitosis, how many telomeres are present in a cell is which 2n = 12
48
The genotype of particular pea plant in TtYy, corresponding to a phenotype of tall & yellow. How many different types of gametes are expected to be produced by this individual?
4
During gametogenesis _____ sperm cells are made from one and ______ egg cells are made from one Oocyte
4,1
One cat carries heterozygous, long haired traits (Ss) & it mate carried homozygous SS traits (ss). Use a Punnett square to determine the probability of one of their offspring having long hair.
50%
How many nucleotides do you need to encode for Ala-Val-Ser-Pro-Ser peptide?
15
In studying T cell divisions in response to specific antigen, you decide to ... these T cells with antigen and examining the gases that are activated by the interactions to do this, following information you should involve?
mRNA
The enzyme RNA polymerase binds
to the promoter region
Transcription factors
regulate gene expression
You are examining an enzyme associated w/ glycolysis. As such, you would expect the
protein to be constitutively expressed
The situation in which an active regulatory protein "turns on" expression is an example of
Positive control
tRNA moves through the ribosome complex in the following order
aminoacyl site, peptidyl site, exit site
The anticodon on the tRNA
is complementary to the nucleotide triplet (codon) on mRNA
mRNA cap
increases mRNA stability, helps mRNA positioning in the ribosome & helps mRNA recognition by ribosomes
Poly(A) tail on mRNA
is protective against degradation, increases stability, can help recognition, helps transport from by the ribosome
A cell that has lost its capacity to grow in vitro as a monolayer and has strated growing suspended in the media is now?
anchorage independent
The classification of cancers into carcinomas, sarcomas, & lymphomas is based on?
Which cells gave rise to the cancers
In cancer, cell division is uncoupled from cell differentiate. What does it mean?
Normally, when cells divide, 1 can differentiate, 1 keeps dividing. In cancer, both can keep dividing
The correct order of events in metastasis of a cancer is?
Angiogenesis, Invasion, Transport, New site
What is a minimal number of nucleotides you need to mutate to change to?
9