Question 1: Which of the following is not passive transport? A. Simple diffusion B. Endocytosis C. Facilitated diffusion D. Osmosis Question 2: The process by which macromolecules within the cell are packaged into secretory vesicles and transported OUT through the cell membrane is known as A. Counter transport B. Co-transport C. Endocytosis D. Exocytosis Question 3: Cells in our body are able to communicate with each other. Which statement about cell signalling is false? A. The same signal always induces the same response in any cell B. Signals act of different ranges C. Cells may respond to sets of signals D. Signals can have different chemical natures Question 4: The release of signalling molecules from a cell that stimulate a neighbouring cell is an example of which type of cell signalling? A. Signalling via Gap junctions B. Paracrine signalling C. Endocrine signalling D. Cell-cell recognition Question 5: Which of the following molecules is not part of a plasma membrane? A. Sphingolipid B. Cholestrol C. Glycolipid D. Triacylglycerol Question 6: If a signal sequence is removed from an ER protein: A. the protein remains in the cytosol. B. the protein will enter an organelle other than the ER. C. the protein will be immediately degraded. D. the protein will be exported from the cell. Question 7: All of the following statements correctly describe nuclear transport, EXCEPT: A. Small proteins diffuse through rapidly B. It involves relatively pores in the inner and outer membrane of the nucleus C. Allow movement of molecules into and out of the nucleus. D. Transport of very large proteins through pores is passive; i.e., does not require an energy source. Question 8: Which of the following statement is TRUE: During the transport of proteins between the nucleus and the cytoplasm, A. GTPase-activating protein (GAP) triggers GTP hydrolysis and converts Ran-GTP to Ran-GDP. Guanine exchange factor (GEF) converts Ran-GTP to Ran-GTP. B. GTPase-activating protein (GAP) triggers GTP hydrolysis and converts Ran-GDP to Ran-GTP. Guanine exchange factor (GEF) converts Ran-GDP to Ran-GTP. C. GTPase-activating protein (GAP) triggers GTP hydrolysis and converts Ran-GTP to Ran-GDP. Guanine exchange factor (GEF) converts Ran-GDP to Ran-GTP. D. Guanine exchange factor (GEF) triggers GTP hydrolysis and converts Ran-GTP to Ran-GDP. GTPase-activating protein (GAP) converts Ran-GDP to Ran-GTP. Question 9: The ER signal sequence on a growing polypeptide chain is recognized by a signal recognition particle (SRP) in the cytosol. This interaction: A. causes the polypeptide chain to dissociate from the ribosome. B. guides the ribosome and its polypeptide to the ER membrane C. causes the ribosome to return to the pool of free ribosomes in the cytosol. D. speeds the synthesis of the polypeptide chain. Question 10: The electron transport chain accepts high-energy electrons from: A. ATP. B. pyruvate. C. NADH and FADH2. D. acetyl CoA
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Endocytosis. Endocytosis is an active transport process where cells take in molecules or particles by engulfing them with the cell membrane. Question 2: The correct answer is D. Exocytosis. Exocytosis is the process by which macromolecules within the cell are Show more…
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Q1. Select ALL that apply to the functional characteristics of the electron transport chain (ETC): A. The ETC transfers electrons from NADH and FADH2 to oxygen. B. The ETC pumps protons into the matrix from the intermembrane space. C. The ETC oxidizes pyruvate into acetyl-CoA. D. The ETC pumps protons across the inner mitochondrial membrane. Q2. Select ALL that apply to the physical components of the electron transport chain: A. The proteins that make up the ETC contain iron-sulfur clusters and heme groups that act as electron carriers. B. The proteins that make up the ETC are primarily free-floating in the mitochondrial matrix. C. The proteins that make up the ETC are transmembrane proteins. D. Some of the proteins that make up the ETC are responsible for pumping protons from the intermembrane space into the mitochondrial matrix. Q3. Which of the following is/are true of glycolysis? (Select ALL that apply.) A. It does not produce ATP or NADH. B. It converts glucose to pyruvate. C. It produces CO2. D. It requires oxygen. E. It occurs inside the mitochondria. Q4. Which of the following is/are true of the citric acid cycle? (Select ALL that apply.) A. It occurs in the mitochondrial matrix. B. Pyruvate directly feeds into the citric acid cycle. C. It occurs in the cytoplasm. D. It transfers electrons from acetyl-CoA to the universal electron acceptors NAD+ and FAD. E. It sequentially oxidizes acetyl-CoA into CO2. F. It requires oxygen. Q5. Select the molecules below that are the reactants or products for glycolysis or the citric acid cycle. Select ALL that apply for each question. Part 1. Glycolysis Select the reactant or reactants for glycolysis: A. Acetyl-CoA B. Carbon Dioxide C. FADH2 D. Glucose E. NADH F. Pyruvate Select the product or products of glycolysis: A. Acetyl-CoA B. ATP C. Carbon Dioxide D. FADH2 E. Glucose F. NADH G. Pyruvate Part 2. Citric Acid Cycle Select the reactant or reactants for the citric acid cycle: A. Acetyl-CoA B. ATP C. Carbon Dioxide D. FADH2 E. Glucose F. NADH G. Pyruvate Select the product or products of the citric acid cycle: A. Acetyl-CoA B. Carbon Dioxide C. FADH2 D. Glucose E. NADH F. Pyruvate Q6. Select ALL that apply for EACH question. Part 1. Where does glycolysis occur? Select ALL that apply: A. Cytosol B. Golgi C. Mitochondria D. Lysosome Part 2. Where does ATP synthesis occur? Select ALL that apply: A. Cytosol B. Golgi C. Mitochondria D. Lysosome Part 3. Where does the most ATP synthesis occur? Select ALL that apply: A. Cytosol B. Golgi C. Mitochondria D. Lysosome Part 4. Where does oxidative phosphorylation occur? Select ALL that apply: A. Cytosol B. Golgi C. Mitochondria D. Lysosome Part 5. Where does the citric acid cycle occur? Select ALL that apply: A. Cytosol B. Golgi C. Mitochondria D. Lysosome Q7. Which of the following is required for facilitated diffusion across a membrane? (Select ALL that apply.) A. A protein channel B. Concentration gradient of the cargo across the membrane C. ATP Q8. Recall that the inside of a phospholipid bilayer is hydrophobic, such that hydrophilic molecules cannot readily diffuse through a cell membrane. Which of the following would require a protein channel to cross a cell membrane? (Select ALL that apply.) A. chloride ions (Cl-1) B. sugar molecules C. Oxygen (O2) D. amino acids Q9. Which of the following determines whether or not a substance will diffuse across a cell membrane? Select ONE option: A. Whether the substance is polar or nonpolar B. Whether the substance is large or small C. Whether there is a concentration difference on either side of the membrane D. All of the above Q10. A single ATP synthase is capable of generating about 30 ATP molecules for every 100 protons that flow through its F0 complex. If we isolated a mutant ATP synthase in which one of its three beta-subunits could not bind ADP, how many ATP molecules would this mutant be expected to generate for every 100 protons that flow through it? Select ONE option: A. 30 ATP molecules B. 20 ATP molecules C. 10 ATP molecules D. 0 ATP molecules
Sri K.
1. A solution with a pH below 7 is ____________ a. logarithmic. b. acidic. c. neutral. d. basic. 2. Which element is the backbone of all organic compounds? a. carbon b. nitrogen c. oxygen d. phosphorus 3. Changing the number of electrons of an atom changes its: a. charge b. element c. ion d. isotope 4. All living things must maintain a constant internal environment to function properly and does so through the process of _______________. a. homology b. biogenesis c. heritability d. homeostasis 5. Two elements that share electrons are said to have formed a(n) ___________ bond. a. hydrogen b. ionic c. covalent d. carbonic 6. Fats, oils, waxes and steroids are examples of what______________. a. carbohydrates b. proteins c. nucleic acids d. lipids 7. Sugar, starch and cellulose are all examples of ______________. a. carbohydrates b. proteins c. nucleic acids d. lipids 8.______________works to keep biological conditions within a specific normal range and acts to decrease deviations from normal. a. Karma b. Positive feedback c. Negative feedback d. Neutral feedback 9. Enzymes are responsible for ______________________. a. Structure b. stored energy c. lowering the activation energy of a reaction d. stored info 10. Photosynthesis generates ________, which are used as an energy source in both plants and animals. a. carbon dioxide b. sugars c. oxygen d. water 11. Which of the following can affect the rate of enzyme-mediated reactions? a. salt concentration b. temperature c. pH d. all of the above 12. After the complete oxidation of glucose some of the energy is now stored in molecules of ATP, NADH and FADH2. Energy conversion is not 100% efficient, what has happened to the remaining energy? a. It becomes water. b. It increases. c. It is lost as waste heat. d. It recycles back to glucose. 13. In humans, which substance is produced in the absence of oxygen during strenuous activity? a. carbon dioxide b. lactic acid c. alcohol d. glycogen 14. Diffusion of water through a semi-permeable membrane is a. diffusion b. active transport c. passive transport d. osmosis 15. A eukaryote has ________________. a. a nucleoid region b. mitochondria c. a nucleus d. Golgi apparatus 16. An example of passive transport is a. Sodium-potassium pump b. phagocytosis c. diffusion d. Hydrogen pump 17. An example of _______is when ions cross a membrane at transport proteins that require energy. a. diffusion b. active transport c. passive transport d. facilitated diffusion 18. Immerse a living cell in a hypotonic solution, and water will tend to a. diffuse into the cell b. diffuse out of the cell c. show no net movement d. move in by endocytosis 19. Which is a principle of the Cell Theory? a. Cells are the basic units of matter. b. All cells arise from preexisting cells. c. All organisms are not made of one or more cells. d. All matter consists of at least one cell. 20. Multicellular organisms were able to evolve in part due to the evolution of a. lysosomes b. cell-cell junctions c. flagella d. chloroplasts 21. You are looking at a cell under a microscope and you immediately recognize it as an plant cell because you see ____________________. a. a cell wall b. a central vacuole c. lysosome d. a & b 22. ___ are cell organelles that contain DNA and can be used to reconstruct evolutionary relationships. a. Lysosomes b. Glogi apparatuses c. Mitochondria d. Ribosomes 23. Suspended in the eukaryotic cell’s cytoplasm are tiny ___________________. a. flagella b. organelles c. organs d. little green men 24. Chromatids that are attached at the centromere are called _____________ chromatids? a. mother b. sister d. brother d. father 25. Cancer primarily results due to __________________. a. uncontrolled cell division b. centrosome c. centromere d. cell plate 26. Daughter cells resulting from meiosis________________. a. have the same number of chromosomes as the parent cell b. have both homologous pairs c. have half the chromosomes as the parent cell d. all of the above 27. Which of the following is not part of sexual reproduction? a. A haploid sperm fuses with a haploid egg in a process called fertilization. b. Diploid germ cells give rise to haploid gametes. c. Gametes are produced by a process called mitosis. d. Crossing over and independent assortment during meiosis contribute to genetic diversity in offspring. 28. How does the sequence of a strand of DNA correspond to the amino acid sequence of a protein ? This concept is explained by the central dogma of molecular biology which states that: a. RNA is used to make DNA. b. DNA is used to make Protein which is used to make RNA. c. Proteins are manufactured directly from DNA without any intermediate. d. None of the above 29. The series of three consecutive mRNA bases coding for one specific amino acid in a protein is called a a. intron. b. exon. c. transposon. d. codon. 30. The chromosome is essentially the same as : a. condon b. intron c. chromatin d. exon 31. A(n) _____ mutation is when a wrong nucleotide gets placed into a strand of DNA a. translocation b. inversion c. frame shift d. insertion 32. tRNA ____________ a. is produced during the process called translation. b. is an integral component of ribosomes. c. carries the proper amino acid to the ribosome d. is responsible for the DNA. 33. The single stranded molecule that is transcribed from a DNA template and is subsequently used to guide the manufacture proteins is _________. a. mRNA b. rRNA c. snRNA d. tRNA 34. What is a gene? a. All the genetic material. b. All the DNA in a nucleus of an eukaryotic cell. c. A continuous strand of RNA d. A sequence of DNA that specifies the sequence of amino acids of a particular protein. 35. How many amino acids are coded for by the following mRNA sequence (assuming NO start or stop codons are included): UAUCAUCCCCACACA a. four b. five c. six d. seven 36. Which of the following is one of the roles that our DNA plays? a. DNA attaches to ribosome. b. DNA transfers energy. c. DNA never changes. d. DNA controls the cell. 37. Which one of the following nitrogenous bases is not found in RNA: a. thymine b. cytosine c. uracil d. Guanine 38. In _____________________, the cross between organisms with two different phenotypes produces a third phenotype that expresses both parental traits. a. complete dominance b. co-dominance c. incomplete dominance d. true breeding 39. The cleft (dimple) chin seen in both Kirk and Michael Douglas is an example of one’s _________ a. genotyope b. phenotype c. haplotype d. tintype 40. In genetics,dominant refers to an allele that _______________. a. requires 2 copies to be expressed b. requires only 1 copy to be expressed c. hidden d. B and C 41. People with Kleinfelter syndrome have 47 chromosomes, including three sex chromosomes (XXY). What is the term used to describe the mistake that occurs during meiosis that results in this abnormal chromosome number? a. independent assortment b. crossing over c. recombination d. nondisjunction 42. If two people who are both carriers for a genetically inherited fatal recessive disease decide to become parents, what will be the odds that their children will also be get the disease? a. 25% b. 50% c. 75% d. 100% 43. If a person with AO blood type marries a person with OO blood type, what are their kids possible blood types? a. AB only b. A or O c. A only d. A, B, or O 44. Which of the following is correct concerning sex-linked characteristics? a. Sex-linked characteristics can be found on either the X or Y chromosome. b. Hemophilia and red-green color blindness are X-linked genetic disorders. c. Daughters of a color blind male are always color blind. d. a, b & c. 45. Being able to curl up your tongue into a U-shape is under the control of a dominant allele at one gene locus, which means in the homozygous recessive condition the tongue cannot be rolled. A woman who can roll her tongue marries a man who can also roll his tongue. Their 1st child can’t roll her tongue. What are the phenotypes of the parents? a. tt, tt b. TT, TT c. Tt, Tt d. Tt, TT 46. A true breeding plant _________________. a. is heterozygous for the trait of interest. b. is homozygous dominant for the trait of interest. c. is either homozygous dominant or homozygous recessive for the trait of interest. d. is homozygous for trait 47. Height and weight are examples of ___________________variation. a. discontinuous b. continuous c. non-inherited d. recessive 48. Which is most closely associated with the process of artificial selection? a. The large variety of breeds of dogs. b. A male lion's mane. c. The evolution of mimicry certain insects. d. A desire of males to mate with certain females. 49. A group of mice becomes separated by the formation of a river. Over time, the northern mice became smaller and whiter, while the southern mice became larger and browner. This is an example of __. a. gigantification b. industrial melanism c. divergence d. homology 50. The individual considered less fit, in the evolutionary sense, would be the __. a. individual with least amount of offspring b. longest lived individual c. individual who produces the greatest number of fertile offspring d. strongest individual 51. Which concept was not included in Charles Darwin's theory of natural selection? a. human genome b. overproduction of offspring c. struggle for existence d. survival and reproduction of the fittest 52. Because of prolonged drought, the trees on an island are producing nuts that are much smaller with thicker and harder shells. This example illustrates ___ selection. a. stabilizing b. disruptive c. directional d. artificial 53. Which of the following is likely to have been the product of sexual selection? a. bright colors of female flowers b. the ability of desert animals to concentrate their urine c. camouflage coloration in animals d. a male lion's mane 54. The process in which a population moves into a relatively unexploited environment and then undergoes rapid evolutionary divergence to produce many separate species is called __. a. ontogeny b. convergent evolution c. disruptive selection d. adaptive radiation 55. A certain species of land snail exists as either a cream color or a solid brown color. Intermediately colored snails are rare. This illustrates __ selection. a. disruptive b. random c. stabilizing d. directional 56. Many introduced (invasive) species have had deleterious effects on communities and ecosystems because __. a. the introduced species are long-lived b. predators prefer the introduced species c. coevolved parasites and competitors are absent in the new habitat d. they become easy prey 57. If biological magnification of a toxin occurs, the ___ will have the highest levels of toxins in their systems. a. producers b. herbivores c. primary carnivores d. top carnivores 58. Which of these is not a population density-dependent regulating factor? a. stress b. competition c. disease d. earth quake 59. An ecological niche is an organism's_______ in an ecosystem. a. function b. habitat c. location d. resources 60. No matter how rapidly a population grows, it will eventually reach a limit and begin to stabilize. This is called the ___ of the environment. a. growth rate b. succession c. carrying capacity d. life history 61. Sea anemones growing on the backs of crabs that damage the the crabs are an example of a. Parasitism b. Commensalism c. Mutualism d. Competition 62. All of the populations of different species that occupy and are adapted to a given area are referred to by which term? a. community b. biosphere c. species d. niche 63. A successful parasite will __. a. kill its host fairly rapidly b. benefit its host c. be able to feed without killing its host d. not harm its host 64. This biome contains the second greatest diversity of plants and animals a. rainforest b. desert c. tundra d. savanna 65. Science is one very interesting area of study because it is a. interesting b. important c. relevant to my life d. a, b, & c
Adi S.
The nuclear pore complex (NPC) creates a barrier to the free exchange of molecules between the nucleus and cytosol, but in a way that remains mysterious. In yeast, for example, the central pore of the NPC has a diameter of 35 $\mathrm{nm}$ and is $30 \mathrm{nm}$ long, which is somewhat smaller than its vertebrate counterpart. Even so, it is large enough to accommodate virtually all components of the cytosol. Yet the pore allows passive diffusion of molecules only up to about 40 kd; entry of anything larger requires help from a nuclear import receptor. Selective permeability is controlled by protein components of the NPC that have unstructured, polar tails extending into the central pore. These tails are characterized by periodic repeats of the hydrophobic amino acids phenylalanine (F) and glycine (G). At high enough concentration $(\sim 50 \mathrm{mM})$, the FG-repeat domains of these proteins can form a gel, with a meshwork of interactions between the hydrophobic $\mathrm{FG}$ repeats (Figure $\mathrm{Q} 12-2 \mathrm{A}$ ). These gels allow passive diffusion of small molecules, but they prevent entry of larger proteins such as the fluorescent protein mCherry fused to maltose binding protein (MBP) (Figure Q12-2B). (The fusion to MBP makes mCherry too large to enter the nucleus by passive diffusion.) However, if the nuclear import receptor, importin, is fused to a similar protein, MBP-GFP, the importin-MBP-GFP fusion readily enters the gel (Figure $\mathrm{Q} 12-2 \mathrm{B}$ ). A. $\quad$ FG-repeats only form gels in vitro at relatively high concentration $(50 \mathrm{mM}) .$ Is this concentration reasonable for FG repeats in the NPC core? In yeast, there are about 5000 FG-repeats in each NPC. Given the dimensions of the yeast nuclear pore $(35 \mathrm{nm} \text { diameter and } 30 \mathrm{nm} \text { length })$ calculate the concentration of FG-repeats in the cylindrical volume of the pore. Is this concentration comparable to the one used in vitro? B. A second question is whether the diffusion of importin-MBP-GFP through the FG-repeat gel is fast enough to account for the efficient flow of materials between the nucleus and cytosol. From experiments of the type shown in Figure $\mathrm{Q} 12-2 \mathrm{B}$, the diffusion coefficient $(D)$ of importin-MBP-GFP through the FG-repeat gel was determined to be about $0.1 \mu \mathrm{m}^{2} / \mathrm{s}$. The equation for diffusion is $t=x^{2} / 2 D,$ where $t$ is time and $x$ is distance. Calculate the time it would take importin-MBP-GFP to diffuse through a yeast nuclear pore $(30 \mathrm{nm})$ if the pore consisted of a gel of FG-repeats. Does this time seem fast enough for the needs of a eukaryotic cell?
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