Bio 1A Part 1: Practice Questions + Explanations
Cells use microfilaments and microtubules to move organelles around the cell. Which one of the following is a common requirement for all such movement? a) A fluid membrane b) A cilium c) ATP d) Cell movement by crawling or swimming
C
Which ONE of the following explains why ice floats on liquid water? A) Higher mobility of water molecules in ice B) More stable H-bonds between water molecules in ice C) Solutes excluded from water in ice. D) Air trapped in ice
B: The more stable H-bonds between water molecules in ice allow the molecules to be more spaced apart, making it less dense than liquid water and therefore can float.
Electron flow along the inner mitochondrial membrane is responsible for which of the following: A) Contributes to the proton motive force that drives ATP synthesis. B) All of the listed choices. C) Reduction of O2 to H20 D) Oxidation of NADH and FADH2
B: You know this :) Just remember... Reduction = gain electron/Hydrogen Oxidation = lose electron/Hydrogen
Consider the properties of glucose in its monosaccharide and polysaccharide forms.Label the following anomers of glucose. Which is alpha and which is beta?
Beta glucose (OH above the plane). Alpha glucose (OH below the plane)
Why do we do we refer to the direction of synthesis of DNA and RNA as 5'-3'? a) Because the two strands of DNA are antiparallel. b) Because Watson and Crick initiated that convention. c) Because the 3' terminus is the growing end of a strand. d) Because the 5' terminus is the growing end of a strand.
C
For the following, list whether they can be found in bacteria (B), animal cells (A), and/or plant cells (P).
Membrane-bound nucleus: A / P Chloroplast: P Ribosomes: B / A / P Endoplasmic reticulum: A / P Cell wall: B / P Golgi apparatus: A / P Mitochondria: A / P Lysosome: A / P
You have purified the functional form of protein X. You decide to analyze the protein subunits found in protein X by using gel electrophoresis using a polyacrylamide gel in the presence of SDS. Describe the role of SDS and polyacrylamide?
Explain in own words.
Briefly explain energy processes in the creation of a polymer. Use the following words in your description: anabolic, catabolic, dehydration, endergonic, exergonic, free energy, hydrolysis, spontaneously, non-spontaneously.
Explain in your own words.
Explain the first law of thermodynamics in your own words. Can mitochondria create energy?
Explain in your own words.
Explain the second law of thermodynamics. Why can't mitochondria achieve 100% efficiency from a pure physics standpoint?
Explain in your own words.
Green Fluorescent Protein (GFP) and immunofluorescence both take advantage of fluorescence to study cells and cell function, however these techniques work in different ways. If you wanted to visualize a protein in a living cell, which of these two imaging techniques would you use? How do you attach the fluorescent tag to your protein of choice?
Explain in your own words.
In lecture we discussed the creation of temperature sensitive lethal yeast mutants. What is the benefit of using such mutants, and which types of genes would be best probed using them?
Explain in your own words.
You have engineered yeast to produce the secreted protein insulin in the lab. Your lab partner asks you how cells sort secreted proteins like insulin from non-secreted proteins. How would you describe this process to your lab partner?
Explain in your own words.
In Sodium - K+ ATPase transporters, 3 Na+ are transported to the cytoplasm and 2 K+ towards the extracellular fluid. (T/F)
False, 3 Na+ are transported towards the extracellular fluid and 2 K+ towards the cytoplasm.
Voltage-gated channels in nerve cells participate in depolarization of the membrane; once the channel is open, it remains open for a couple of seconds to ensure the signal arrives at its destination. (T/F)
False, the channel is soon inactivated (refractory phase) to ensure the signal is directionally propagated and the channels don't remain open.
Voltage-gated K+ channels selectively discriminate K+ from NA+ based on their charge. (T/F)
False, they discriminate by size (radius).
QUIZ 1: If and when we discover life on distant planets, which one of the following molecules is most likely to be present? H2O DNA CO2 RNA
H2O: It's the most important molecule for life. Cohesion, Adhesion, High Heat of Vaporization, and High Heat Capacity make water the essential molecule that it is.
Fill out the table that compares and contrasts how we typically characterize DNA and RNA: 1) Sugar 2) Bases 3) Single or double stranded 4) Main function
DNA: 1) 2-Deoxyribose 2) AGTC 3) Double stranded 4) Encodes genetic information 1) Ribose 2) AGUC 3) Single stranded 4) Is an intermediary for DNA and protein
Which ONE of the following amino acids can NOT exist in stereoisomeric forms? (refer to Lecture 2 Poll Questions pdf for drawing) a) Alanine (Ala, A) b) Valine (Val, V) c) Leucine (Leu, L)d) Glycine (Gly, G) e) Isoelucine (Ile, I) f) Methionine (Met, M)
E
If a protein is in an aqueous environment, which of the amino acids above would you expect to find on the surface of the protein?
Lysine, Serine, Cysteine, Aspartic Acid (hydrophilic molecules)
A reaction has a starting enthalpy of 50 joules, and an ending enthalpy of 25 joules. It occurs at a temperature of 200K. It has a change in Entropy of 10 Joules/K. a. What is the change in Gibbs free energy of this reaction? b. Is this reaction spontaneous or non-spontaneous? How can you tell? c. Imagine that this reaction is coupled in a cell with a reaction that has a change in Gibbs free energy of 5000 joules. What do you expect to happen? In other words, would these reactions occur spontaneously or not? Why would that be the case? d. Would this coupled reaction be faster than a reaction with a Δ G = -3000 J?
a. -2025 (do math) b. Spontaneous because negative delta G c. If coupled, the net Δ G is positive,-2025 + 5000 = +2975 joules so the two reactions would not occur without an additional net input of energy d. No! The Δ G is not an indicator of speed, just spontaneity.
In ligand-gated channels at the synapse, vesicles from the nerve terminal fuse with the plasma membrane, releasing neurotransmitters that bind and activate the ion channels on the receptor cell. (T/F)
True, why?
When the sodium - K+ ATPase transporter is phosphorylated, it leads to a conformational change that promotes the release of Na+ by reducing its affinity. (T/F)
True, why?
List some characteristics that are shared by bacteria & archaea, archaea & eukarya, and bacteria & eukarya.
REVIEW CHARACTERISTICS OF 3 DOMAINS Bacteria & Archaea: No nuclear envelope Few/absent membrane enclosed organelles Archaea & Eukarya: No peptidoglycan in cell walls Several types of RNAPInitiator AA for protein synthesis Bacteria & Eukarya: Unbranched membrane lipids
Starch and cellulose are two polysaccharides composed of glucose monomers. Which is composed of alpha glucose monomers and which is composed of beta glucose monomers?
Starch - linked via alpha 1, 4 linkages Cellulose - linked via beta 1,4 linkages
a. When DNA is polymerized, which end of the DNA molecule are bases added to? 5' or 3' b. What is the functional group present at this location? c. During addition of a new nucleotide, what is the functional group that reacts with the group named in part b?
a. 3' b. OH group c. Phosphate group
The environment within a lysosome is more ______ (acidic/basic) than the cytoplasm. How is the pH level achieved (what mechanism)? Why is it beneficial for a cell?
acidic ATP-driven proton-pump Different compartment and acidic environment for the hydrolytic enzymes.
Lipids in the bilayer membrane tend to move freely by ____________ (lateral / flipping) movement. On the other hand, ____________ (lateral / flipping) movement would require energy and proteins to assist in the process.
lateral flipping
Skin cells from normal and FH disease patients show defects in LDL uptake by mutant cells. Answer the following questions regarding this case study: a. Normal cells showed _____________ (more / less) LDL bound than FH cells.
more, why?
The hydrogen bonds in water explain which ONE of the following properties? A. High heat capacity of water. B. The dipole moment of a water molecule. C. The dense packing of frozen water molecules D. The fluidity of the lipid bilayer.
A
Which ONE of the following molecules does not contain a glycosidic linkage? a) Glucose b) Glycogen c) NAD+ d) Adenosine
A
Which one of the following explains how an integral membrane protein can be assembled into the ER membrane: A. Through a protein translocation channel in the ER membrane. B. By direct insertion of the membrane anchor domain into the ER bilayer. C. By translocation through the nuclear pore complex and then into the ER. D. By vesicle fusion to the ER membrane.
A
Label the functional groups of cortisol and its analogs. (refer to Worksheet 1 for image) How many chiral carbons are in cortisol? Which synthetic analog would you expect to better imitate cortisol in the cell? Why?
7 Analog 1. Explain why in own words.
An aqueous solution with the hydroxide concentration is 10-6 M has a pH of _______.If OH concentration = 10-6 M then proton (hydronium) concentration is 10-8 M.
8
Which kind of bonds or interactions are important for the different levels of protein structure (1 ̊, 2 ̊, 3 ̊, 4 ̊)?
1 ̊ - Covalent peptide bonds 2 ̊ - Hydrogen bonding of backbone (alpha helix or beta sheets) 3 ̊ - Side chain interactions (ionic salt bridges between charged amino acids, h-bonds between polar amino acids, covalent disulfide bonds, hydrophobic core, hydrophilic surface) 4 ̊ - hydrogen bonds, salt bridges, van der waals (weak interactions between polypeptides chains)
Match the following polymers to facts about their synthesis: A. Nucleic acids B. Proteins C. Polysaccharides 1) ___ Created by combining sugars through dehydration reactions 2) ___ Formed by peptide bonds between carboxyl group of an existing polymer, and amino group of an incoming monomer 3) ___ Result from the translation of the genetic code 4) ___ 5' C of Incoming monomers is attached to the 3' Carbon of a ribose or deoxyribose sugar 5) ___ Include an energy consuming alpha-beta phosphoanhydride bond
1) C 2) B 3) B 4) A 5) A
CO2 and H2O differ in their polarity. Why? a) The hydrogen covalent bonds to oxygen in water are polar whereas the carbon-oxygen bonds in CO2 are not. b) Because water molecules can form hydrogen bonds to each other but CO2 molecules cannot. c) Because CO2 transitions directly between a gas and solid state. d) The polar bonds of oxygens in CO2 are symmetrical whereas in water the hydrogens are asymmetric.
A
Fluorescence microscopy using fluorescent molecules attached to antibodies and GFP fluorescence allows the visualization of cell structures composed of distinct proteins. Which of the following experiments can be conducted on living cells? a) GFP visualization of mitochondrial movement in living cells. b) Fluorescent antibody detection of chromosome segregation in living cells. c) Scanning electron microscope imaging of fluorescent red cells moving through capillaries. d) GFP visualization of insulin secretion in thin section electron micrographs.
A
Membranes with short chain-length fatty acids influence the membrane bilayer in the same way as do fatty acids with unsaturated bonds. Which ONE of the fluid properties of a membrane will be affected by short chain fatty acids? a) Lower the temperature at which the membrane transitions from fluid to frozen. b) Increase the membrane viscosity. c) Decrease the rate of recovery in a FRAP experiment. d) Increase the phase transition temperature.
A
Which of the following amino acids are apolar/nonpolar? There are 4 answers. (refer to Lecture 3 Poll Questions pdf for drawing) a) Methionine (Met, M) b) Proline (Pro, P) c) Phenylalanine (Phe, F) d) Tyrosine (Tyr, Y) e) Tryptophan (Trp, W) f) Aspartic acid (Asp, D) g) Glutamic acid (Glu, E) h) Asparagine (Asn, N)
A B C E
Select the two correct statement(s) regarding membrane proteins. A) The LDL receptor spans the bilayer B) Some membrane proteins are electrostatically bound to the surface of a membrane. C) The LDL receptor has mostly hydrophobic amino acids. D) Na+ and K+ channel proteins are electrostatically bound to membranes.
A and B
Carbon-carbon double bonds impose which TWO of the following properties on organic molecules? a. create options to have cis- and trans isomers b. closer packing of fatty acids in a membrane bilayer. c. create a more fluid membrane bilayer at room temperature when fatty acids have double bonds. d. Change the equilibrium isomerization of hexoses
A and C
DNA replication proceeds bidirectionally from a loop of open chromosome exposing complementary single strand templates. Which two of the following statements about replication from one fork is CORRECT? A. Only one of the two strands serves as a template for continuous synthesis of the complementary strand. B. Both strands serves as a template for continuous synthesis of the complementary strands. C. Both strands require the synthesis of RNA primers to initiate DNA synthesis. D. Only one of the two strands require the synthesis of RNA primers to initiate DNA synthesis.
A and C
The endosymbiont hypothesis for the origin of mitochondria is most consistent with the membrane structure of the following ---. A) Gram - bacteria B) Eukaryotic microorganism C) Gram + bacteria D) Archaeal prokaryote
A) Gram negative bacteria is a type of prokaryote (aligning with the endosymbiont hypothesis) that have 2 membranes, which is why they resemble mitochondria. Gram positive bacteria only have 1 membrane. Archaeal prokaryotes just have an outer membrane.
Match the following statements with the correct properties of water: a) A property of water that is mainly responsible for cooling down with sweat. b) The frequent formation and dissociation of hydrogen bonds in liquid water allow the absorption of a large amount of heat without dramatically changing the temperature. c) Water molecules form hydrogen bonds with different substances. d) Water molecules form hydrogen bonds with neighboring water molecules.
A) high heat of vaporization B) high heat capacity C) adhesion D) cohesion
Indicate whether the following amino acids are nonpolar, polar, negatively charged and/or positively charged at physiological pH (~7.4). Also indicate which amino acid(s) can form disulfide bonds and label the functional group that is involved. (refer to Worksheet 2 for image)
A. Polar, positively charged B. Polar C. Nonpolar D. Nonpolar E. Polar, forms disulfide bonds via the sulfhydryl functional group (-SH) F. Polar, negatively charged
Which ONE of the following statements about an enzyme with a high Km is correct? A) Requires a higher substrate concentration for catalysis. B) Has a higher temperature optimum of catalysis. C) Has a higher pH optimum for catalysis. D) Will reach an equilibrium in the conversion of a substrate to a product faster.
A: A high Km means that more substrate is required for the enzyme to be effective. You want a low Km because then the enzyme is really effect, even at low substrate concentrations. Yes, enzymes usually work better at high temperatures (too high though will stop its function). And each enzyme has a pH optimum, but this varies per enzyme. These two factors will determine the efficacy of the enzyme. Enzymes speed up reactions by lower the activation barrier, but the products will always be the same.
Acetate derived from pyruvate is coupled to coenzyme A to begin the TCA cycle.Why is this pathway considered cyclic? a) Because pyruvate combines with oxalacetate to form citrate which proceeds in steps of CO2 and electron release back to oxalacetate. b) Because it powers the rotation of the ATP synthase in a counterclockwise cycle. c) Because it powers the rotation of the ATP synthase in the clockwise direction. d) Because electrons and protons flow back and forth across the mitochondrial inner membrane.
A; The Citric Acid Cycle is a way to produce NADH and FADH2 for the next steps of respiration. Acetyl-Coenzyme A combines with oxalacetate, of whose carbons becomes CO2 in that cycle. In the next cycle, the carbons from Acetyl-Coenzyme A become CO2. B, C, and D all involve chemiosmosis, not the TCA cycle.
As water melts, the average distance between water molecules increases or decreases?
Average density decreases resulting in an increase in density (mass/volume). Explain why in own words.
Immunofluorescence microscopy can be used for which ONE of the following: A. Visualize the cytoskeleton in a living cell B. Visualize isolated actin filaments placed on a glass slide. C. Visualize the transitions in the structure of hemoglobin bound to O2 D. Visualize chromosomes segregating in real time.
B
Insulin is encoded by one gene but the protein has two polypeptide subunits. Which if the following explains this puzzle? a) The 2 polypeptides are coded by different reading frames of the same mRNA. b) The 2 polypeptides are clipped from N-terminal and C-terminal pieces of a longer polypeptide precursor. c) Complementary mRNAs are made from each strand of the DNA duplexstrands leading to two different polypeptides. d) The ribosome reads two different portions of one insulin mRNA to make different peptides.
B
Proteins made in the cytoplasm that end up inside an organelle require a special transit or localizing signal as part of the primary sequence of the protein. Which of the following experiments would allow you to define the amino acid sequence of such a signal? a) Sequence the gene for a specific localized protein from many different organisms and look for a common sequence shared among the related genes to identify the "sorting signal". b) Make many mutations in the gene for the protein and look for changes that cause the protein to remain in the cytoplasm. These mutations will define the amino acids required for localization. c) Attach the full gene encoding the protein by a gene fusion to the gene for GFP and see if the fusion protein is properly localized. If so, it must contain a signal. d) Isolate the organelle in which the protein is localized and compare the amino acid sequences of many different proteins that share the same location. A common sequence will be the localizing signal.
B
The voltage-gated K+ channel has which ONE of the following properties? a) Initiates a depolarizing action potential b) Selects anhydrous K+ over Na+. c) Uses ATP hydrolysis to import K+ d) Transports 2K+ out for every 3 Na+ taken into the cell.
B
Which of the following cells structures is not enclosed within a membrane bilayer? A. Golgi apparatus B. Cytoplasmic RNA granules C. Lysosome
B
Which of the following properties of a protein is LEAST likely to be affected by thermal denaturation? A. Tertiary structure B. Primary structure C. Secondary structure D. Quaternary structure E. Net charge
B
You have isolated a secretory granule from liver cells. Which of the following properties of membrane and soluble components would you expect to find? A) Soluble secretory proteins will be released if the granules are suspended in iso-osmotic buffer. B) Soluble secretory proteins will be released if the granules are suspended in distilled water. C) Glycans on proteins and lipids will be exposed on the outer surface of intact granule membrane. D) Granules will contain plasmid DNA
B
You are set to study the membrane fluidity of three different cell strains (A, B and C). You conducted a FRAP experiment, measured the fluorescence recovery over time after bleaching, and built the graphs below. In ascending order, contrast the fluidity of the membrane of the different cell strains and explain your rationale. Note that the levels of fluorescence recovery is not quite 100% (graphs are slightly misleading). (refer to Worksheet 3 for image)
B is the most fluid, C the least. C < A < B The longer it takes for the fluorescence to recover in the bleached area, the less fluid the membrane. C took longer than A, which took longer than B. Thus, B cell line has higher fluidity.
Which ONE of the following molecules serves as an intermediate in glycolysis? Note answer choices are shuffled. Be sure to look for the name of the molecule when selecting your answer. A) Glycogen B) Glyceraldehyde 3-phosphate C) Acetyl CoA D) Coenzyme Q
B) Intermmediates are the products of each of the steps of glycolysis (the molecules). Glyceraldehyde 3-phosphate is the initial product after Phase 1 of glycolysis ("energy payoff phase), ie. G3P. Glycogen is a stored version of glucose as a source of potential energy for when glucose is needed. Acetyl CoA is made from pyruvate through pyrvuate oxidation in which it loses a carbon (to make CO2), which is the product of glycolysis. It's used in the TCA cycle by first binding to oxalacetate. Coenzyme Q lies inside the inter-membrane of the mitochondria and is a key player in the electron transport chain: it electron carrier which means it receives electrons from both NADH and FADH2 via Complexes I and II respectively and passes those electrons to Complex III.
Which ONE of the following is not a role played by low density lipoprotein particles (LDL)? A) Delivers cholesterol to tissues in the body B) Required for receptor mediated endocytosis C) Collects in arteries to cause blockage. D) Controls the production of cholesterol by feedback inhibition.
B) LDL is NOT required for receptor mediated endocytosis. LDL is an EXAMPLE of receptor-mediated endocytosis-- there are many types! LDL contains an outer rim of lipoprotein and a cholesterol center, so it delivers cholesterol to tissues in the body. Cholesterol is necessary to regulation of fluidity in the cell membrane. But, when it does not permeate the cell membrane through endocytosis, it builds up, causing artery blockage. And when there is too much cholesterol, feedback inhibition takes place and prevents more cholesterol from being synthesized.
Lysosomes contain hydrolytic enzymes that have an acidic pH optimum. The beta gamma phosphate bond in ATP is broken to drive the formation of the acidic pH In the lysosome. How does this work? A) Protons are pumped into the lysosome by an acid pH optimum ATPase inside the lysosome. B) ATP hydrolysis in the cytoplasm is coupled to proton pumping into the lysosome. C) The phosphate released by ATP hydrolysis is pumped into the lysosome. D) Protons are pumped out of the lysosome by an ATPase in the cytoplasm.
B: ATP hydrolysis, which refers to the breaking of the gamma phosphate from the ATP molecule releases energy (exergonic reaction) helps fuel the proton pump (H+ moving against the concentration gradient) which decreases the pH of the lysosome so the enzymes can work in their acidic pH optimum. ATPase is NOT involved in this process (A and D incorrect). Protons are pumped IN to make it more acidic!
Which of the following structures, if any, is glycogen? A B C D E F
B: Glycogen is composed of long polymer chains of glucose units with an alpha acetyl linkage of a carbonyl and alcohol group. (think sugar rings!) Other answers did not indicate this linkage between functional groups.
Microtubules serve which ONE of the following functions? A) Form the channel in the nuclear envelope for protein import into the nucleus. B) Organize beating movement of cilia. C) Organize muscle contraction. D) Form the channel in the ER membrane for secretory protein translocation.
B: Microtubules are responsible for movement in the cell, with the help of motor proteins like myosin, kinesin, and dynein. In flagella and cilia cells, microtubules promote cell movement AND flow across cells. Specifically, cilia have an organized set of microtubules that slide back and forth to facilitate that movement. Actin filaments and myosin are specifically associated with organizing muscle contraction. In protein translocation, the ribosome binds to a protein translocation complex in the ER membrane, and the secretory protein and then enter.
Hydrogen bonds stabilize secondary and tertiary structures in proteins. Which ONE of the following statements concerning these bonds is correct? A) H-bonds between nitrogen (NH) and carbonyl oxygens (C=O) in the polypeptide backbone stabilize tertiary structures. B) Amino acid side chains participate in H-bonds that stabilize tertiary structures. C) H-bonds in the alpha helix stabilize the base pairs of DNA. D) H-bonds are broken by the oxidation of the SH groups of cysteines to make a disulfide bond.
B: Tertiary structure develop PRIMARILY from the H-bonds between the R-groups (ie. amino acid side chains). The alpha-helix and beta-pleated sheet that form from the H-bonding with the peptide backbone (nitrogen (NH) and carbonyl oxygens (C=O)) account for the *secondary* structure of proteins. Disulfide bonds play a role in just the tertiary and quaternary structures of proteins.
Which one of the following properties is explained by an enzyme that has a very low km? a) The enzyme is inhibited at high substrate concentrations. b) The enzyme binds its substrate with a high affinity. c) The enzyme is allosterically regulated. d) The enzyme binds its substrate with a low affinity.
B; A low Km means that the enzyme has a higher affinity for its substrate. This means that the enzyme requires LESS of the substrate to reach the half-max velocity of the reaction, meaning it's a very efficient enzyme.
Which of the following represents endergonic reactions? a) Catabolic pathways b) Anabolic pathways c) Formation of ADP from ATP. d) Combustion of gasoline
B; Anabolic pathways require energy, meaning they are endergonic and have a positive delta G. A; Catabolic pathways release energy, so they are exergonic. C; the formation of ADP from ATP (ie. ATP hydrolysis because bond is broken) also releases energy, so it is exergonic. D; the combustion of gasoline also releases energy, so it is exergonic.
The activation energy barrier to catalysis is largely overcome by the binding of a hydrolytic enzyme to a substrate whose molecular motions include a transition state between a covalent bond and a hydrolyzed bond. These motions are enhanced at higher but still physiological temperatures. Which one of the following statements is explained by this property of a substrate? a) When an enzyme reaction is conducted at 20 vs 30C, the final extent of substrate hydrolysis is greater at 30C. b) The initial rate of substrate production is enhanced at 30C. c) The initial rate of substrate production is enhanced at 20C. d) The final extent of substrate hydrolysis is enhanced at 20C.
B; Enzymes have an optimal temperature for functioning (~30-35˚C). Enzymes works to speed of metabolic processes, but the products after the reaction is unaffected by the enzyme. So, only the initial substrate concentration is affected by the presence of an enzyme, and higher temperatures increases its efficacy. Therefore, A and D are incorrect because they say the final extent of the substrate is affected, and C is incorrect because it is a lower temperature at which the enzyme would not be as effective.
A key step in glycolysis is the reduction of NAD+ to NADH as part of a complex reaction catalyzed by triose phosphate dehydrogenase. Which one of the following also explains how the substrate of this reaction is used by the dehydrogenase to generate a bond with a highly negative free energy of hydrolysis: a) Transfer of the electron from NADH to pyruvate to generate lactic acid. b) Capture of phosphate to form 1,3 bisphosphoglycerate. c) Transfer of the electron from NADH to the mitochondrion to help generate an electrochemical potential driving ATP synthesis. d) Substrate level phosphorylation to form ATP from ADP and P
B; In the first step of the energy payoff phase of glycolysis (ie. Step 6 of total), the oxidation of the C-H bond in the substrate has a high -delta G, so it is VERY exergonic. Some of that energy released is put towards the reaction from NAD+ to NADH (the H comes from the H from the substrate!), which is endergonic. But also, some of that released energy goes into forming a high-energy bond between the substrate and a phosphate group to form 1,3-bisphosphoglycerate, which is also endergonic. The two endergonic reactions are compensated by the extremely exergonic reaction of the C-H oxidation. NOTE: The oxidized form of NAD+ contains 1 less H than the reduced form of NADH which contains 1 more H. A; This refers to anaerobic glycolysis in which there is a deficiency of oxygen. C; This refers to the electron transport chain. D; This refers to general ATP hydrolysis.
ATP made in the mitochondrion is exchanged with ADP from the cytoplasm to provide fresh ATP for metabolic processes. Which other molecular pairs must also be exchanged across the mitochondrial envelope to sustain oxidative respiration? a) Reduced and oxidized forms of cytochrome c b) CO2 and O2 c) NADH and NAD+ d) Pyruvate and lactate
B; O2 is necessary for the processes of cellular respiration. CO2 is an inevitable byproduct that must be expelled. A; Cytochrome C lives in the inner membrane of the mitochondria and does not get exchanged across the envelope. D; reversible reactions of NADH and NAD+ all occur within their respective spaces, either in the cytosol during glycolysis or the mitochondrial matrix during the Krebs Cycle or Oxidative Phosphorylation. D) This exchange occurs when O2 is deficient an occurs in the cytosol after conversion of glucose to pyruvate.
The free energy of hydrolysis of the beta-gamma phosphoanhydride bond of ATP promotes which one of the following reactions? a) RNA polymerization b) Protein kinase action c) Depolarization of membrane potential d) Rotational movement of membrane phospholipids.
B; The protein kinase enzyme is involved in the phosphorylation of proteins using the phosphate group from ATP. NOTE: The phosphatase enzyme dephosphorylates the protein. A; RNA polymerization does not require a phosphate group from ATP. B; The depolarization of the membrane is not involved with ATP hydrolysis, but instead with the sodium-potassium channel ion flow. C; The rotational movement of membrane phospholipids relates to membrane fluidity (lateral/flipping).
Many biological processes are powered by ATP hydrolysis. Name the molecules involved (blue boxes) and the name of the bonds (red boxes). (refer to Worksheet 3 for image). A) Which phosphate is cleaved? B) Where is the energy stored in ATP? C) Choose the correct option for the following statement: ATP hydrolysis has a Choose the correct option for the following statement: ATP hydrolysis has a Δ G = -7.3 kcal/mole: It's products are more/less stable and have a lower/higher free energy than it's reactants.
Bonds Top to bottom: phosphoester, phosphoanhydride, phosphoester Molecules top to bottom: Adenosine triphosphate, adenosine diphosphate A) beta-gamma B) Phosphoanhydride bonds, not in atoms/molecules themselves. C) more / lower
Covalent and non-covalent bonds may be distinguished by the following properties: a) Covalent bonds are polar. b) Shared electrons define an ionic bond. c) Non-covalent bonds are easily broken by changes in temperature. d) Covalent bonds are apolar.
C
The functional conservation of a yeast and a human gene - CDC2 - involved in cell division control has been documented by which of the following experiments? a) The yeast and human CDC2 genes show a similar nucleotide sequence. b) The human and yeast CDC proteins are both protein kinase enzymes. c) The human gene can work in a yeast cell to replace the activity of the yeast CDC2 gene. d) Genetic complementation may be used to clone the yeast CDC2 gene.
C
You are a biochemist and have just purified a human protein with a novel catalytic activity. You wish to find out exactly how the substrate for this enzyme binds to the catalytic site. Which one of the following techniques would you use? a) Mix the protein with or without the substrate and evaluate on an SDS polyacrylamide gel to determine if the substrate changes the electrophoretic mobility of the protein. b) Clone the gene for the protein and fuse it to the gene for GFP and use fluorescence microscopy to examine cells grown with or without the substrate. c) Form crystals of the protein in the presence or absence of substrate and examine the structures of the two by X-ray crystallography. d) Examine the gene that encodes this enzyme from a variety of organisms to detect amino acid changes that are the most highly variable.
C
You are investigating a drug that blocks the action of the voltage-gated K+ channel. Which of the following properties of drug-treated nerve cells would you expect to find upon treatment? A) A block in membrane depolarization. B) A rapid loss of the balance of Na+ and K+ ions across the membrane. C) Slow repolarization of the membrane potential. D) Reduced dephosphorylation of the Na+/K+ ATPase.
C
An archaeal microorganism uses light to make ATP. Which ONE of the following features of the microorganism's cytoplasmic membrane enables this ATP synthesis? A) A light-activated channel pumps Na+ out of the cell to drive an ATP synthase in the membrane. B) A light activated channel in the membrane stimulates pyruvate kinase to make ATP in the cell. C) A light activated channel pumps protons out of the cell to drive an ATP synthase in the membrane. D) The ATP synthase is a light activated channel that makes ATP by pumping protons out of the cell.
C: Because they can absorb sunlight, bacteriorhodopsin (archaea species) contain a SEPARATE light-activated channel in their membrane that pumps protons out of the cell to drive ATPase (like in the regular electron transport chain). This is very unique.
The Na+/K+ ATPase transfers 3 Na+ ions to the cell exterior for every 2K+ transferred to the cell interior. The balance of cation flow leaves a net electronegative potential of approx. -60mV across the inner surface of the plasma membrane. If no other channel is opened, what happens to the membrane potential if a voltage-gated Na+ channel is opened? A) The membrane potential remains the same. B) The Na+/K+ ATPase is inhibited and the membrane potential gradually rises to 0. C) The membrane potential becomes more positive than -60mV D) The membrane potential becomes more negative than -60mV
C: If a voltage-gated Na+ channel is opened, that means more Na+ will be pumped into the cell, making it the membrane potential more positive than the initial -60mV. Cycle: depolarization opens voltage-gated channels briefly, they go into refractory phase (inactivated), and then close. NOTE: the K+ channel selectively discriminates K+ and Na+ because the pore is lined by amino acid carboxyl groups for which only anhydrous K+ is the proper size (ie. big enough) to coordinate for selective passage through the filter (Na+ not large enough).
Which of the following structures, if any, is a phospholipid? A B C D E F
C: Phospholipids have a hydrophilic, polar head containing a glycerol backbone, phosphate group, and head group AND hydrophobic, non-polar fatty acid tails (unsaturated or saturated).
You have purified insulin from homogenized cow pancreas and wish to establish the purity of your preparation (i.e. free of unrelated protein contaminants). Which ONE of the following techniques would you use to establish the purity of your preparation? A) Fluorescence recovery after photobleaching. B) Thin section electron microscopy of the purified protein. C) SDS polyacrylamide gel electrophoresis D) Indirect immunofluorescence
C: SDS Page is used to separate, purify. and quantify proteins based on their size. Larger proteins don't travel far on the gel whereas smaller proteins travel further. FRAP is used to assess the fluidity of a membrane by assessing its recovery after photobleaching. A quick recovery means the membrane is more fluid. Electron microscopy will not allow you to assess purity of the protein. It's just a visualization technique. Indirect immunofluorescence will not allow you to assess purity of the protein. It's just a visualization technique.
Sugar molecules and fatty acids have many carbon-carbon bonds and yet sugars are polar whereas fatty acids are apolar. Which ONE of the following explains why: A) Sugar molecules are soluble in the cytoplasm whereas fatty acids are not. B) Sugar molecules can form glycosidic linkages whereas fatty acids can not. C) Several OH groups on sugars make them polar whereas fatty acids have only one OH D) Sugar molecules are in equilibrium between linear and cyclized forms whereas fatty acids are not.
C: Several OH groups are attached at the "corners" of sugar rings and fatty acids only have the OH at the end of the fatty acid tail (the part that connects with the head group).
SARS-CoV-2 virus particles consist of an RNA genome packaged into a membrane vesicle with a spike protein on the vesicle surface that allows the virus to bind to a cell surface receptor and be taken into the cell by endocytosis. Once inside the cell, the viral RNA must somehow escape into the cytoplasm before it ends up in the lysosome. Which ONE of the following processes is required for that escape? A) Viral protein export from the nucleus. B) Synthesis of viral proteins. C) Membrane fusion to release the viral RNA D) Transcription of the viral RNA
C: When in the cell, the viral RNA resides in a vesicle that forms through receptor-mediated endocytosis. The only way to escape into the cytoplasm before being hunted by the lysosome is to fuse with the membrane to RELEASE that RNA. That's the first step. At that point, the RNA will undergo processes to replicate and infect the cell.
Some enzymes denatured at high temperature renature reversibly to full enzyme activity. Amino acid side chains participate in catalysis in such renatured proteins because of which one of the following: A) The catalytic residues are located adjacent to one another in the linear sequence of the polypeptide. B) The catalytic residues are reduced to form disulfide bonds to stabilize the folded polypeptide. C) The catalytic residues are organized close to one another in the properly folded polypeptide. D) The catalytic residues are not dependent on H-bonds for catalysis.
C: When the proteins (polypeptides) in catalytic residues are folded properly in an enzyme active site, the amino acid side chains are organized close to one another and participate in H-bonding, electrostatic interactions, and other non-covalent bonding that holds the substrate molecules in the active site, lower the activation energy. EG. Serine protease catalytic triad- aspartate, histidine, and serine. This triad is en example of how enzymes with different substrate specificities can have nearly identical active sites. When unfolded in linear sequence, the side chains are far removed from each other. No disulfide bonds involved in catalysis. H-bonds are indeed required for catalysis!
Kinesin and dynein are motor proteins that move along microtubules in opposite directions. You are studying the movement of a mitochondrion in a nerve cell and wish to know which motor protein is carrying the organelle to a nerve terminal. Which ONE of the following techniques should you use. A) Electron microscopy of living cells to visualize the location of kinesin and dynein in the nerve cell. B) Indirect immunofluorescence with an antibody against a mitochondrial protein. C) Look at a mutant with a defective dynein or kinesin to see if either affect movement. D) Indirect immunofluorescence with antibodies that bind to either kinesin or dynein. E) Use a GFP-tagged mitochondrial protein to inspect organelle movement in a normal cell.
C: You want to see the effect that kinesin or dynein have on the movement of a mitochondrion in a nerve cell. The only way to be able to tell which of these motor proteins is responsible for carrying the organelle is you have to assess what happens when its defective and you know will not be involved. Then, once you account for your 'x' variable, you can assess your 'y' variable. All of the other options either will not pinpoint WHICH of the two proteins will affect movement, or they distinguish them but they look at the while dead, not alive. You can use a live cell technique if you tag the motor proteins themselves.
Plant proteins called lectins can bind to sugar residues on lipids and glycoproteins on the outer surface of cells and cause the glycoproteins to be internalized by endocytosis. Which one of the following will occur if the lectins are internalized by vesicles by budding from the cell surface? a) Cells will regulate the level of production of cholesterol. b) The lectin carbohydrate complexes will face the cytoplasmic surface of the vesicle. c) The lectin carbohydrate complex will face the lumen of the endocytic vesicle. d) Lectin-containing vesicles will be secreted from cells.
C; During receptor-mediated endocytosis of lectins, the lectins bind to the glycolipids and glycoproteins (important for cell signaling) and are engulfed by the membrane becoming vesicles in the cytoplasm. The only thing the lectin carbohydrate complex would be exposed to is the lumen of the vesicle. A; This refers to a specific example of receptor-mediated endocytosis that is not related to the endocytosis of lectins. B; It cannot face the cytoplasmic surface of the vesicle because that refers to the outside of it. D; They will not be secreted because they are being internalized in this process.
Cells growing in low O2 convert pyruvate to lactic acid for one of the following purposes: a) To prevent mitochondrial autophagy. b) To stimulate the TCA cycle. c) To regenerate NAD+. d) To stimulate production of ethanol.
C; In conditions of low O2, the NADH produced during glycolysis is directly used to convert pyruvate to lactic acid in that the NADH "drop off" its electrons, producing then NAD+. This ensures a steady supply of NAD+ for when the aerobic processes of respiration can ensue once oxygen is available again. This process is called lactic acid fermentation. A; In this context, autophagy occurs when mitochondria have defects in the respiratory chain and the lysosome needs to do damage control. B; The TCA cycle comes later in cellular respiration. D; Not related...
The cooperative binding of 02 to the heme groups on the hemoglobin tetramer explains why: a) Low 02 in the tissues fed by blood capillaries causes hemoglobin to retain oxygen. b) High 02 in the blood vessels of the lung explains why oxygen is cooperatively released from hemoglobin. c) O2 binding to one globin subunit facilitates the binding of subsequent O2 molecules to the other subunits. d) O2 binding causes the progressive polymerization of sickle cell mutant hemoglobin.
C; The O2 binding to one globin subunit/heme group changes the shape or conformation of the enzyme that facilitates the binding of a second, third, and fourth O2 molecules to the other subunits. This is an example of positive allosteric regulation.
Oubain is a toxic molecule that inhibits the N+,K+ ATPase by blocking the hydrolysis of the phosphate ester bond that was created by the ATPase in the first stage of the cation pumping reaction. Which of the following will happen as a result of this inhibition? a) Excess Na+ will be pumped into the cell. b) Excess Na+ will be pumped out of the cell. c) K+ will not be pumped into the cell. d) K+ will not be pumped out of the cell.
C; Without the N+, K+ ATPase functioning, the process does not occur: the 3 Na+ ions that would normally be pumped out are not, and the K+ ions that would normally be pumped in are not. There is a LACK of action, so no excess of any ion will be flowing in this scenario.
Electronegativity measures the tendency of an atom to attract shared electrons to itself. Which atom in table salt is most electronegative?
Chlorine
Carbon-carbon bonds are apolar and yet sugars, fatty acids and sterols differ dramatically in water solubility. Which one of the following explains this difference? a. Sugars are soluble because they exist in an equilibrium between linear and cyclized forms b. Fatty acids and sterols are apolar because they exist in membrane bilayers. c. Fatty acids and sterols are apolar because their synthesis requires a dehydration reaction. d. Sugars have many more hydrophilic hydroxyl groups than do fatty acids and sterols.
D
Ribosomes contain RNA and protein subunits and are assembled in the nucleolus. Which of the following events must occur for the ribosome to function in protein synthesis? A. Ribosomal proteins must be made in the nucleus. B. The nucleolus must be exported from the nucleus. C. Ribosomal RNA must be made in the cytoplasm and then imported into the nucleus. D. Ribosomal proteins must be imported into the nucleus.
D
Which of the following observations support the endosymbiont origin of mitochondria and chloroplasts. a) Membrane envelope organization similar to that of a prokaryote. b) Organelle genes are similar to those of prokaryotic ancestors. c) Respiratory and photosynthetic membrane components similar to prokaryotic ancestors. d) All of the above
D
Which of the following properties of the water molecule depends on its polarity? a) Hydrogen bonding between molecules in solution b) Adhesion to other surfaces c) Dipole moment of the water molecule d) All of the above
D
You are an eager young investigator starting a research project using genetics to discover the genes required for eukaryotic cellular DNA replication. Which one of the following techniques and applications would be the best place to start? a) Look for gene deletion mutations that block DNA replication in human cells grown in cell culture. b) Look for mutations in yeast cells that block DNA replication but not colony formation at 37C. c) Look for mutations in E. coli cells that block DNA replication and colony formation at 42C. d) Look for mutations in yeast cells that block DNA replication and colony formation at 37C.
D
Insulin is secreted as a protein with two polypeptide chains linked by disulfide bonds. Which one of the following properties applies to the biosynthesis of insulin? A. Two mRNAs code for the different polypeptide subunits. B. Insulin is secreted in response to glucose deprivation. C. The disulfide bonds in insulin form as a result of a reduction reaction on cysteine residues. D. Insulin is synthesized as a longer precursor that is proteolytically processed before secretion.
D Note: C is not correct as this forms from an oxidation, not reduction.
Actin filaments and the motor protein myosin propel which one of the following cellular movements: A) Ciliary beating in epithelial cells (airway of humans) B) Import of proteins into the ER lumen. C) Flagellum rotation in E. coli D) Cytoplasmic streaming in plant cells
D: Apart from muscle contraction in humans, actin filaments and myosin (which is ATP-powered) facilitate cytoplasmic streaming in plant cell f(think lab!) to transport molecules and organelles. Ciliary beating in lungs is facilitated by an organized set of microtubules and dynein mediates. Also requires ATP. Protein translocation complexes are involved in the import of proteins into the ER lumen (ribosomes tightly bound). Flagella have internal microtubules that promote movement/rotation of bacteria like E. coli (also, sperm cells). Also requires ATP.
Pruvate kinase uses the high free energy of hydrolysis of phosphoenolpyruvate to make ATP from ADP. Which ONE of the following enzymes is also able to use a glycolytic intermediate e to generate ATP from ADP. Note the image below shows the structure of the glycolytic intermediate and the name of the corresponding enzyme. Note PEP + ADP is converted to pyruvate and ATP by pyruvate kinase. The ADP is not shown. A) Phosphofructokinase B) Aldolase C) Phospohoglucoisomerase D) Phosphoglycerokinase
D: Kinases are involved in the addition of a phosphate group. Phosphoglycerokinase is comes in at Step 10 of glycolysis. Phosphofructokinase (PFK) is involved in dephosphorylation at Step 3 of glycolysis. ATP is its negative allosteric regulatory (more ATP means less PFK) and slows down glycolysis. Aldolase is involved in cleavage at Step 4 of glycolysis. Phospohoglucoisomerase is involved in isomerization at Step 2 of glycolysis.
Which of the following structures is adenosine? A B C D E F
D: The "A" in ATP! It is composed of an adenine (one of the nucleobases: GC*A*T-->contains nitrogens) and ribose sugar connected by a glycosidic bond. NOTE: Amino acids have an amine/o group, alpha carbon with attached hydrogen, carboxyl group, and R group (which individualizes each amino acid- 20 total).
Which one of the following processes releases water (a dehydration reaction)? A) Opening of a voltage-gated ion channel. B) Sucrose hydrolysis C) Lysosomal ATPase D) Nucleotide polymerization.
D: When water is release, that means an -OH group and hydrogen leave their respective molecules to bond to each other and form H2O. This is dehydration. This process occurs in nucleotide polymerization to form phosphodiester bonds between polymers and form nucleic acids (DNA and RNA).
Where do electrons flow during the generation of an electrochemical potential in respiring mitochondria? a) To the matrix space side of the mitochondrial inner membrane. b) From NADH to flavin mononucleotide. c) From complex IV (cytochrome oxidase) to O2. d) All of the above.
D; All correct. A; Electrons are transported through the inner membrane of the mitochondria in the chain of proteins. B; This passing of electrons occurs in the electron transport chain in complex I. C; The electrons are ultimately passed off to oxygen (electronegative atom), combining with protons to form H2O.
Which of the following process(es) results in a -∆G? a) Dissolving a sugar cube in water. b) Biosynthesis of glutamine from glutamate within a cell. c) 5'-3' polymerization of RNA within a cell. d) All of the above
D; All of these processes are overall exergonic, meaning they are favorable and spontaneous.
You wish to isolate the voltage-gated Na+ channel from a nerve cell membrane. How would you begin to isolate the active protein from the membrane in which it is located in a nerve cell? a) Break the nerve cells and suspend membranes in a solution of high ionic strength to break electrostatic interactions to enable the channel protein to be released in a soluble supernatant fraction. b) Clone the gene for the channel protein and introduce it into yeast cells in order to secrete the protein into the culture medium. c) Break the nerve cells open term-51and treat the membranes with SDS followed by electrophoresis on a denaturing SDS polyacrylamide gel. d) Break the nerve cells and suspend membranes in a mild non-ionic detergent designed to free the channel protein from surrounding phospholipids.
D; Detergent is used to free membrane proteins because they can disrupt the hydrophobic-hydrophilic system of the phospholipid bilayer that constitutes the cell membrane.
Endergonic reactions in glycolysis are driven forward by which one of the following: a) Reduction of NAD+ to NADH. b) Substrate level phosphorylation. c) Oxidative reactions in the mitochondrion. d) Mass action.
D; I don't get this one.
Is O2 polar or apolar? Carbon-carbon bonds?
Explain in own words.
The CDC2 gene encodes an enzyme required to initiate the cell division cycle. What happens to a yeast cell when the CDC2 gene is deleted?
Explain in own words.
What are two reasons why life likely evolved to be carbon-based?
Explain in own words.
You showed your classmate an image of a eubacteria and its environment, and you explained that cholesterol plays an important role in these organisms by reducing the membrane fluidity. Your classmate responds that they have recently read an article stating that cholesterol instead increases membrane fluidity; the article was describing the physiological aspects of a new fungal species found in Antarctica (a psychrophilic organism). a. Do you think one of the statements about the role of cholesterol is wrong? If not, briefly explain why.
Explain why in your own words.
Which of the following structures, if any, is a triglyceride? A B C D E F
F: Not shown! A triglyceride has a glycerol backbone (3-carbon molecule) "esterified" (double-bonded oxygen, carbon, oxygen) with three fatty acids. Other answers did not indicate this ester linkage.
After running the gel and staining the gel you see the four bands (two closely migrating doublets of proteins) shown in lane 1 (image to the right). Protein migrated from the top to the bottom. A standard was also included but not shown in the gel image. The standard is a mixture of known proteins and their sizes. Based upon this you have identified four subunits, 1-4, and their sizes are 30 kDa, 40 KDa, 150 kDa and 160 kDa. Label the correct bands. (refer to Worksheet 2 for image)
From the bottom up = 30 kDa, 40 KDa, 150 kDa and 160 kDa
Label the components of the phospholipid depicted below. Which parts of the phospholipid are hydrophilic? Which are hydrophobic? (refer to Worksheet 1 for image) A) Glycerol B) Head group C) Unsaturated Fatty Acid D) Saturated Fatty Acid E) Phosphate
Hydrophilic: A, B, E Hydrophobic: C, D
Based upon the AA shown which of the following amino acids are likely to allow a protein to bind to nucleic acids? Aspartate Cysteine Lysine Glutamate Arginine
Lysine and Arginine. Explain why in own words.
In class we talked about the S (smooth) and R (rough) bacteria strain experiment, which provided evidence that DNA is the heritable genetic material responsible for making the non-pathogenic strain pathogenic. Using your knowledge of this experiment, complete the following table: S strain R strain Heat killed S strain Heat killed S strain + R strain Heat killed S strain treated with protein degrading enzyme + R strain Heat killed S strain treated with DNA degrading enzyme + R strain
S strain: Pathogenic R strain: Non-pathogenic Heat killed S strain: Non-pathogenic Heat killed S strain + R strain: Pathogenic Heat killed S strain treated with protein degrading enzyme + R strain: Pathogenic Heat killed S strain treated with DNA degrading enzyme + R strain: Non-pathogenic
On lane 2 indicate (approximately) where a protein with a molecular weight of 70 kDa would migrate.
See image.
Define the unit of calorie.
The amount of energy required to increase the temperature of one gram of water one degree celsius.
If life has evolved on another planet in a distant solar system, which ONE of the following molecules will be most essential for that life to exist? DNA Bilayer membranes Proteins molecules Water
Water. Explain in own words.
Identify each of the following as elements (E), molecules (M), and/or compounds (C). Water Sucrose Table salt Iron Nitrogen gas Glycine
Water: MC Sucrose: MC Table salt: C Iron: E Nitrogen gas: M Glycine: MC
Match the organelles/compartments (a-k) to their functions/features (1-11). a) Ribosome b) Nucleus c) Flagella d) Lysosome e) Peroxisome f) Endoplasmic reticulum g) Golgi apparatus h) Mitochondria i) Chloroplast j) Cytoskeleton k) Plasma membrane 1. The site of cellular respiration 2. Degrades macromolecules 3. Synthesizes new polypeptides 4. Modifies and sorts proteins 5. Acts in cellular motility 6. Protects the genetic material 7. Organelle that carries out photosynthesis 8. Synthesizes lipids and secretory proteins 9. Allows for movement of organelles, vesicles, and chromosomes within the cell 10. Converts hydrogen peroxide into water 11. Separates interior environment of the cell from exterior environment and can selectively control export and import of molecules of various sizes and chemical properties
a) Ribosome: 3 b) Nucleus: 6 c) Flagella: 5 d) Lysosome: 2 e) Peroxisome: 10 f) Endoplasmic reticulum: 8 g) Golgi apparatus: 4 h) Mitochondria: 1 i) Chloroplast: 7 j) Cytoskeleton: 9 k) Plasma membrane 11
Describe the isomeric relationship between the following pairs of molecules. (refer to Worksheet 1 for images)
a) trans/cis isomers b)structural isomers c) enantiomers
Circle the correct choice to describe the following reaction: The terminal phosphate of ATP is released through a (condensation/hydrolysis) reaction. This reaction (uses/yields) water and (uses/yields) energy.
hydrolysis; uses; yields
Match the following techniques (A-J) appropriately with the experimental goal EXPERIMENTAL GOAL i) Examining the localization of insulin within a cell ii) Examining membrane fusion at the edge of a cell in real-time iii) Determining the atomic structure of a macromolecule iv) Separating a protein of a known size A) Immunofluorescence B) GFP fusion protein C) Super resolution light microscopy D) Electron microscopy E) X-ray crystallography F) Cell fractionation G) SDS-PAGE
i) Examining the localization of insulin within a cell: a, b, c, d, f ii) Examining membrane fusion at the edge of a cell in real-time: b,c iii) Determining the atomic structure of a macromolecule: d, e iv) Separating a protein of a known size: f, g
In the cell, when transit of ions and small diffuse across the membrane along the concentration gradient, the transport is said to be _______. On the other hand, in order for the cell to mediate transit of molecules against the concentration gradient, it needs _______, a process known as _______ transport.
passive energy active