cell biology final - Southgate
the net result of the breakdown of glucose in glycolysis and fermentation is the production of:
2 ATP
How many chromosomes does an individual human person have?
46
How many oxygen molecules (O2) are required each time a molecule of glucose (C6H12O6) is completely oxidized to carbon dioxide and water via aerobic respiration?
6
Phospholipase C is activated by
Ga
Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.
Which of the following represents the largest group of biological classification?
Kingdom
which stage of aerobic respiration produces ATP and NADH and releases CO2?
Krebs Cyce/Citric Acid Cycle
Which of the following is true about cystic fibrosis?
Patients with the most common mutation make a CFTR protein that is not present in the membrane.
The glomeruli are structures in the kidney that help filter the blood. The glomerular filtrate concentration/plasma concentration (UFx / Px) is a measure of how easily a substance can pass through the pores of the capillaries in the glomerulus. Based on the table, which of the following is true about the ease of which serum albumin can pass through the pores of the capillaries?
Serum albumin is too large to pass through the pores in the capillaries.
Which disease is an example of a frameshift mutation?
Tay-Sachs disease is caused by a 4 base pair insertion.
in pancrine signaling, the signaling molecule
acts on cells in close proximity to the secreting cell
when two atoms differing in electronegativity are joined in a covalent bond, then the:
atom with the greater electronegativity attracts there bonded electrons more strongly
What feature is common to prokaryotes, fungi, and plants? _______
cell walls
Thylakoids, DNA, and ribosomes are all components found in ________.
chloroplasts
a protein containing several proline residues is:
not likely to form alpha helices
What is the outer boundary of the cell?
plasma membrane
in glycolysis, the most reduced compound formed is:
pyruvate
In the reaction NAD+ + H+ + 2e− ® NADH, NAD+ becomes:
reduced
Genetic information is transferred from the nucleus to cytoplasm by way of _______________.
ribonucleic acid
A solution of starch at room temperature does NOT readily decompose to form a solution of simple sugars because ________.
the activation energy barrier for this reaction cannot easily be surmounted at room temperatures.
Aquaporins are:
water channels
Which of the following enters a target cell's nucleus and acts directly on the genes?
* estrogen
products of the Krebs cycle include:
- carbon dioxide x2 - NADH x2 - FADH2 x2
How does inhibition of the Na+/K+ ATPase increase the force of heart muscle contraction? Hint: help from a sodium-calcium exchanger.
It increases cytosolic Na+ in the cell and therefore decreases Ca2+ export.
Coenzyme Q is involved in electron transport as
a lipid-soluble electron carrier
Fatty acids usually have an even number of carbons in their structures. They are catabolized by a process called beta-oxidation. The end products of the metabolic pathway are acetyl groups of acetyl-CoA molecules. These acetyl groups _______.
directly enter the citric acid cycle.
Which of the following organisms is a vertebrate?
frog
which type of bond must be broken for boiling water to vaporize?
hydrogen bonds
which on of the following is associated with bacterial cells?
ribosomes
Changes in the genetic makeup of an organism may be due to which of the following?
- New combinations of chromosomes - Chromosome mutation - Gene mututation
Cholesterol blends with phospholipids in a biomembrane that cholesterol molecules are defined as being
Hydrophilic and hydrophobic at the same time
Why is ATP an important molecule in metabolism?
It provides energy coupling between exergonic and endergonic reactions.
Eggs are protein rich foods. An uncooked egg can catalyze a reaction that breaks down bacterial cell walls. After cooking, this activity is almost abolished. This Is likely because:
the enzyme became denatured
It can be said that some proteins in the cell membrane are like "icebergs floating in a sea of lipids." These embedded proteins that span the whole width of the membrane and "poke out" on the inside and the outside are called:
transmembrane proteins.
Describe, in detail, the structure of a chloroplast:
- OUTER MEMBRANE - INNER MEMBRANE - INTERMEMBRANE SPACE - STROMA - THYLAKOID MEMBRANE THAT DOES NOT PRODUCE CHLOROPHYLL - THYLAKOID LUMEN/SPACE, PROTON STORAGE - NUCEOID DNA - Chloroplasts have granula/grana which are stacks thylakoid membranes. Thylakoid membranes are intramolecular membrane systems that produce the chlorophyll that gives plants its color. Chlorophyll absorbs orange-red wavelengths of light and reflects green wavelengths. The actual photosynthetic processes, such as the light reaction photosystem II and photosystem I, occur in the thylakoid lumen which is a liquid interior. This part is all part of the light dependent process of photosynthesis. The light-independent process of photosynthesis, its the Calvin Cycle which is located also in chloroplasts.
In which of the following cases is energy NOT needed for transmembrane transport?
- Potassium ions (K+) move out of the cell down the K+ concentration gradient via potassium channels. - Glucose moves into the cell down its concentration gradient via a glucose uniporter
which statements are correct?
- Remake was first to propose the tenet that all cell arise from other cells - Leeuwenhoek was the first to observe unicellular organisms in pond water
Which of the following statements are correct about the phospholipid molecules in the plasma membrane?
- The phospholipid heads face outward. - The phospholipid heads are attracted to water. - The phospholipid tails are not attracted to water. - Each phospholipid molecule has one polar head.
which of the following enzymes takes part in the citric acid cycle
- citrate synthase - malate dehydrogenase - iso-citrate dehydrogenase
What mechanisms can terminate an intracellular signaling pathway once the concentration of an external signal decreases?
- deactivation of a signal transduction protein - desensitization of receptors - degradation of the second messenger
what are common intracellular second messengers?
- inositol 1,4,5-triphosphate (IP3) - 1,2-diacglycerol (DAG) - 3'-5' cyclic guanine monophosphate (cGMP)
Which of the following is a noncovalent interaction?
- van der Waals interactions - ionic interactions - hydrophobic effect
the human body contains an estimated _______ proteins that form based on the way _______ amino acids can combine.
100,000; 20
From its atomic number of 15, it is possible to predict that the phosphorus atom has ________.
15 protons and 15 electrons
knowing that this element has an atomic number of 16, you should be able to predict that the sulfur atom has
16 protons and 16 electrons
Describe in general terms how the muscle Ca2+ ATPase pumps Ca2+ ions from the cytosol into the sarcoplasmic reticulum.
A P-class Ca2+ ATPase located in the SR membrane of the skeletal muscle pumps Ca2+ from the cytosol into the lumen of the SR. This pump is the major integral membrane protein in SR membranes and hence can be readily purified. Ca2+ pumping from the cytosol to the SR involves a series of ordered steps and two conformational states of the pump, termed E1 and E2. In the E1 state, the pump binds two cytosolic Ca2+ ions and ATP. The ATP is cleaved to ADP with phosphorylation of an aspartic acid with a high-energy acyl phosphate. Next, a reduction in the energy state of the aspartate acyl phosphate produces a conformational change in the protein from the E1 to E2 state. In the E2 state, the affinity of the pump for Ca2+ is 1000-fold less and both calcium ions are released into the SR lumen. With dephosphorylation of the pump, there is a second conformational change and the pump reverts again to the E1 state.
A multicellular organism is:
A group of differentiated eukaryotic cells that work together to support the function of an organism
Plants and animals grow by producing more cells through mitosis. Cytokinesis is the process that allows a growing cell to be separated into two cells. Which of the parts of the diagram describe how cytokinesis happens in animal cells?
Actin and myosin comprise the contractile ring which forms the cleavage furrow by pinching the cell in half.
Which of the following allows water to move MUCH FASTER across cell membranes?
Aquaporins
What happens to FADH2 and NADH when they transport hydrogen atoms to the electron transport chain?
Both become oxidized
Which of the following are NOT organelles found in animal cells?
Chloroplast and central vacuole
The glucose molecule has a large quantity of energy in its ________.
C—H bonds.
The first step in the secretory pathway that should be inhibited by a non-functional mutant of NSF is:
ER to Golgi transport.
Which of the following is a statement of the first law of thermodynamics?
Energy cannot be created or destroyed.
Which of the following directly (as opposed to indirectly) supports Charles Darwin's theory of evolution?
Evidence from Genetics
Which of the four classes of ATP-powered pumps share overall similarity: several subunits, the same general organization, and a similar function in being H+transporters?
F-class pumps and P-class pumps
The myometrium is smooth muscle tissue found in the uterus that permits the flow of ions to coordinate contractions in response to hormones. Cells in tissues are connected in a variety of ways. Which type of connection would permit the flow of ions between smooth muscle cells in the myometrium?
Gap junctions connect the cytoplasm of adjacent cells allowing the movement of ions and signaling molecules between cells.
The ATP synthase responsible for most of the ATP synthesis in the body is located:
On the inner side of the inner mitochondria membrane,
The net effect of photosynthesis, chemically, is reduction, leading to the formation of which products?
Oxygen and carbohydrates
Which components of PSII are responsible for producing the proton-motive force?
Several components of PSII contribute to the proton-motive force, albeit by different mechanisms. First, the removal of electrons from water by P680generates protons in the thylakoid space. Next, the delivery of electrons by quinone Q to cytochrome bf is accompanied by the transfer of two protons from the stroma to the thylakoid lumen. Finally, protons may be transported from the stroma to the thylakoid space by cytochrome bf functioning in a Q cycle.
How does uniport transport compare with simple diffusion?
Simple diffusion is reversible but uniport transport is not.
The genetic code is redundant . This means that
Some amino acids are coded from more than one codon.
At the beginning of most recipes for bread, you are instructed to dissolve the yeast in a mixture of sugar (sucrose) and hot water, in some cases with a small amount of flour. Within a short time, this yeast mixture begins to bubble and foam, perhaps to the point of overflowing the container. What is happening?
The bubbles are carbon dioxide that yeast produce as they break down the glucose and produce ATP via fermentation.
Describe the endosymbiont theory of eukaryotic evolution and list the key evidence supporting it.
The endosymbiont theory states that long ago a primitive protoeukaryote engulfed (phagocytosed) one or two different prokaryotic organisms and the organisms developed a symbiotic relationship where each would receive certain benefits. The evidence for this includes the fact that prokaryotes and chloroplasts/mitochondria are approximately the same size, both have circular DNA molecules like bacteria, both have similar ribosomes to bacteria, and both have their own internal series of independent membranes.
Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages found in cellulose. Why ?
The geometry of the bonds is different, & the shapes of enzyme active sites are highly specific
Which best describes how phospholipids prevent hydrophilic molecules from crossing the plasma membrane?
The hydrophobic tails prevent large and/or hydrophilic molecules from crossing the membrane without assistance.
Why are fermentation reactions important for cells?
They regenerate NAD+ so that glycolysis can continue to operate.
Which of the following is an example of potential rather than kinetic energy?
a molecule of glucose.
The primary role of oxygen in cellular respiration is to ________.
act as an acceptor for electrons and hydrogen, forming water.
Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's ________.
activation energy
The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of ________.
an endergonic reaction coupled to an exergonic reaction.
cGMP phosphodiesterase catalyzes the conversion of
cGMP to 5'-GMP
what is the difference between covalent bonds and ionic bonds
covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms
Which feature of a phospholipid promotes the membrane's fluidity in the winters?
double bonds in the fatty acid tail(s)
which of the following is true about protein folding?
elements from the secondary structure are also maintained in the tertiary structure
A chemical reaction that has a positive ΔG is best described as ________.
endergonic
A cell uses which of the following to accelerate chemical reactions enabling its metabolic machinery to operate?
enzymes
The functional unit of heredity is the _____________.
gene
an archaea cell found in an abandoned quarry is found to have a very high concentration of protons. It is likely that this cell:
has low pH and is acidic
Biological evolution of life on Earth, from simple prokaryote-like cells to large, multicellular eukaryotic organisms, ________.
has occurred in accordance with the laws of thermodynamics
Where are proteins produced OTHER THAN on ribosomes free in the cytosol or ribosomes attached to the ER?
in mitochondria
In a plant cell, DNA may be found ________.
in the nucleus, mitochondria, and chloroplasts.
In terms of thermodynamics, diffusion occurs as a result of a(n):
increase of entropy.
the discovery of the structure of DNA was useful because
it suggested a mechanism for copying and preserving the genetic material
Amino acid entry into cells can occur via uniporters or symporters. If the rate of leucine entry into the cell increases when the pH decreases, this suggests:
leucine is being transported by a H+ symporter.
Suppose a young boy is always tired and fatigued, suffering from a metabolic disease. Which of the following organelles is most likely involved in this disease?
mitochondria
Which of the following membrane activities REQUIRES energy from ATP?
movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid
Which of the cellular organelles are enclosed by TWO cellular membranes?
nucleus
in the ancient seas, which of the following are totally absent?
oxygen
Which of the following describes the fluid-mosaic model of the plasma membrane structure?
phospholipid bilayer with embedded proteins
All of the following statements describe the process of photorespiration, EXCEPT:
photorespiration generates substantial amounts of ATP.
The amount of chemical energy stored in a gram of table sugar is a measure of its ___________________________ energy.
potential.
if you disrupt all the hydrogen bonds in a protein, what level of protein structure will be preserved?
primary structure
Peripheral proteins bound to the exoplasmic face of the plasma membrane can also bind to:
proteins of the ECM
All of the following are similarities between unicellular organisms and multicellular organisms, except _____________.
size
which of the following is defined as the tertiary structure of a protein?
structural domains such as a DNA-binding domain
The catalytic properties of an enzyme's active site are most directly dependent upon the enzyme's:
substrate
According to the induced fit hypothesis of enzyme catalysis, ________.
the binding of the substrate changes the shape of the enzyme's active site.
Knowing the atomic mass of an element allows inferences about which of the following?
the number of protons plus neutrons in the element
GTPases serve in many signal transduction pathways and the presence of GTP or GDP dictates whether the pathway is on or off, respectively. Which of the following statements is TRUE regarding guanine nucleotide exchange factors (GEF) and the role in these signaling pathways?
they catalyze the dissociation of GDP on the G-protein and promote the replacement of GTP