sentia chapter 4 & 5 + ch. 4 Campbell bio textbook practice questions
Give an example of how cytoskeletal elements help in the sexual reproduction of animals.
- microtubules form flagella in sperm cells which aid in cell movement
What is the most active cell communication process happening in your body right now for you to see, hear and sense the surroundings?
- synaptic signaling nerve cell communication E: G protein receptors are used by signaling molecules such as epinephrine, hormones, and NEUROTRANSMITTERS
A sewage line broke and contaminated the drinking water source of a rural town. You are asked to investigate if there is any bacterial contamination after fixing the sewage leak. What methods would you follow?
- use light microscope and then electron microscope if it is a small bacteria
Lipids and carbohydrates do not have any charges associated with them, making it difficult to separate them by gel electrophoresis. What methods are good for separating such molecules?
-. Carbohydrates can be initially purified by centrifugation and then various techniques such as calorimetric identification of simple vs complex carbohydrates and spectroscopic analysis will give approximate results. For further identification and determination of their nature, mass spectrometry (MS) and gas chromatography (GC) are used. -Initial separation can be done with Thin Layer Chromatography (TLC) and the detailed analysis is done by High-Performance Liquid Chromatography (HPLC), mass spectrometry (MS), and gas chromatography (GC).
Rigor Mortis refers to the stiffening of an animal body after death. Propose a hypothesis as to why this stiffening occurs after death.
-The deposition of calcium keeps the actin and myosin to stay contracted in the microfilaments. -Lack of ATP prevents the relaxation of the muscles
A person in a coma has been diagnosed with head injury and brain swelling. To reduce the brain swelling, doctor prescribed mannitol (a sugar not easily transported through membrane and not easily metabolized) through intravenous injection. Discuss and suggest how this treatment would reduce brain swelling.
-mannitol is a hypertonic solution causing swelling to reduce as it exits into the higher concentrated solution
When you are eating artificial sweeteners such as Splenda, which part of the signaling mechanism is primarily responsible to make you feel them as a sweet substance similar to table sugar; is it reception, transduction, or response?
-reception Splenda is a modified sucrose, called sucralose. It binds to taste buds (receptors for sweet substance) and triggers the response of tasting something sweet. The body cannot metabolize sucralose and it passes through the digestive system. The response of "tasting sweet" is due to the reception of the signal sucralose.
RNA considered being the first genetic material formed even before DNA because it can _________________ and ___________________________
-store information and act as enzymes. e: RNA can help as a template for protein synthesis and for more RNA synthesis. Once proteins (enzymes) are made, they can make carbohydrates and lipids. -In addition, RNA can form variable secondary structures similar to proteins and unlike DNA, which may help in forming ribozymes with different functionalities
Margarita is a cocktail with alcohol, fruit juice and lemon juice. Can you predict which of these component, (alcohol, sugars and citric acid) in this margarita will go through the cell membrane slowly or rapidly to reach the blood?
-sugars and glucose are large molecules so will not be able to cross rapidly, -alcohol is an ethanol which dissolves lipids and is able to enter rapidly
If the dimension of a cube shape cell is 10 µm, the ratio of cell surface area to volume would be _____ to 1.
0.6 (10x10x6 : 10x10x10) = (600:1000) = (0.6:1)
List three essential conditions for the formation of life during the early stages of the earth.
1. Availability of water and basic elements such as C, H, O, N, S, P, and basic molecules 2. Optimal temperature and energy available for reactions to occur 3. Reducing conditions that allow bonds to form easily due to low oxygen level E: simple atoms and molecules combine under high temperatures in the presence of water, optimal energy level, limited availability of oxygen
Three essential requirements for an ancestral cell to grow and multiply are 1. ____________________to define the cell and contain reactions within 2. ___________________ make and break molecules and 3. ___________________ material to replicate & reproduce.
1. Cell membrane 2. Enzymes or metabolism 3. Genetic
reconstruct the major time lines in the origin and evolution of life on earth in a logical sequence b
1. Earth formation 2. bacteria fossils 3. cyanobacteria fossils 4. early eukaryotes 5. multicellular eukaryotes 6. humans
D. List three possible evidences you can show to prove the evolution of life on earth.
1. Fossils 2. Structural similarities 3. Physiological similarities 4. DNA sequence similarities
Application: Gaucher's disease is a genetic disorder in which lipids accumulate in cells and certain organs. The disease symptoms include bruising, fatigue, anemia, low blood platelets, and enlargement of the liver and spleen. It is caused by a hereditary deficiency of the enzyme glucocerebrosidase.
1. Lysosome 2. Enzyme supplementation, bone marrow transplant, and diet management
C. List three major requirements in the nature of a life form that can sustain and evolve.
1. Membrane structure to serve as boundary for cell and surface for metabolic reactions 2. Genetic molecule that can store information and be replicated 3. Metabolic activities to consume, process, and release energy.
C. Ribosomes and their functions. 1. Why do antibiotics such as tetracyclin inhibit the bacterial ribosomes, while the eukaryotic ribosomes are not inhibited? 2. Where do the rRNA and ribosomal proteins synthesis take place, what processes made them and where do the subunits get assembled? Organize this information into a flow chart or concept map.
1. antibiotic--tetracycline--inhibits bacterial growth by stopping protein synthesis. Both bacteria and humans carry out protein synthesis on structures called ribosomes. Tetracycline however can only cross the membranes of bacteria and accumulate in high concentrations in the cytoplasm. Tetracycline then binds to a single site on the ribosome--the (smaller) ribosomal subunit--and blocks a key RNA interaction, which shuts off the lengthening protein chain. In human cells, however, tetracycline does not accumulate in sufficient concentrations to stop protein synthesis.
List three different ways cytoskeletal elements are important for sexual reproduction of animals.
1. microtubule in cilia move egg through ♀ reproductive track and microtubule in flagella move sperm once in ♀ reproductive track 2. microfilaments involved in muscle contraction move sperm through and out of ♂ reproductive track 3. intermediate filaments forming nuclear lamina of the egg must dissolve to allow fertilization
A paleontologist estimates that when a particular rock formed, it contained 12 mg of the radioactive isotope potassium-40, which has a half-life of 1.26 billion years. The rock now contains 3 mg of the isotope. About how old is the rock? Enter in billions of years.
2.52 Since the amount is halved twice (12 to 6 and then to 3 mg), it took 2 half-lives to reach there. Hence 2 x 1.26 = 2.52 billion years.
How many different types of ribosomes are found in a plant cell? Hint: consider the various locations of the plant genome.
3
If the dimension of a cube shape cell is 1 µm, the ratio of cell surface area to the volume would be _____ to 1.
6
How many cellular structures the rough endoplasmic reticulum is associated with? (structurally and functionally)
8 1. Cell membrane 2. Nucleus 3. E.R 4. Gogli 5. Lysosome 6. Vacuole 7. Chloroplasts 8.Mitochondria(possibly also peroxisome)
Which of the following will affect the fluidity of a cell membrane? A) Sterols B) oligosaccharides C) saturation levels of fatty acid side chains D) peripheral proteins E) phosphate head group
A & C) saturation levels of fatty acid side chains E: saturated will cause lipids to tightly pack and makes the membrane less fluid while unsaturated causes kinks preventing the tight packing of lipids and increasing fluidity. -cholesterols also affect fluidity: It acts as a fluid buffer. It makes it more fluid in very cold temperatures, by not allowing the membrane to come in too close. In too-warm temperatures, it decreases fluidity.
A high level of LDL (Low-density lipoprotein) - cholesterol found in blood (serum) is a major risk factor for heart disease. Such high cholesterol may be due to diet or genetic make-up. Which of the following may be the reason for a vegan to have high levels of serum LDL cholesterols? A) Synthesis of cholesterol by the liver B) Lack of membrane receptors to take up cholesterol C) Consumption of cholesterol in the vegan diet D) A and B E) A and C
A and B -cholesterol is not present in plants so no dietary consumption and may only be a cause of genetics.
Refer to the ECG chart segment shown above and answer the following question. Which proteins will be responsible for the depolarization from Q to R? A) Na+-K+ pump moving 2 K+ in and 3 Na+ out B) H+ pump transporting protons inside C) ATP synthase pumping ATP outside D) Voltage gated K+ channel pumping K+ outside E) Voltage gated Na+ channel pumping Na+ inside
A) when potassium leaves and sodium is pumped inside would be depolarization while 2 potassium being pumped inside and 3 Na+ leaves would be Repolarization.
Which of the following is/are a highly specific mechanism(s) of cell transport? Select ALL possible answers. A) Active transport B) Receptor mediated endocytosis C) Simple diffusion D) Facilitated diffusion E) Osmosis
A) Active transport B) Receptor mediated endocytosis D) Facilitated diffusion
Which of the following affects all others in the cell communication process? A) Signal reception B) Change of receptor shape C) Signal transduction D) Transcription and translation E) Physical and physiological response
A) Signal reception
Phosphorylation of a series of proteins ("phosphorylation cascade") during signal transduction _____. A) causes target proteins to change their shape and therefore their activity. B) brings a conformational change to the cell's DNA. C) cannot occur in yeasts because they lack protein phosphatases. D) always results in enzyme inactivation inside the target cell. E) causes binding of a hormone to a cytosol receptor.
A) causes target proteins to change their shape and therefore their activity.
Both mitochondria and chloroplast are maternally inherited. Some plants develop resistance to atrazine herbicide through a mutation of a gene located in the chloroplast. If male plants without any such herbicide resistance are crossed with an atrazine-resistant female plant, what will be the resistance level of offspring plants? A) All offspring will be resistant. B) None of them will be resistant. C) Half will be resistant and half susceptible. D) Only the female plants will be resistant and not the male plants. E) Only the male plants will be resistant and not the female.
A) All offspring will be resistant. E: Since mitochondria and chloroplasts are only inherited from the mother, all offspring will have the genes located on those organelles. All offspring will have inherited the resistant gene from their mothers as the chloroplasts can only be inherited from mothers.
Based on the characters of the three domains, which ones will be the most rapidly dividing cells that may be found inside animals? A) Bacteria only B) Archaea only C) Eukarya only D) A and B are possible
A) Bacteria only
You have isolated some organisms that are unicellular with cell walls containing peptidoglycan and have flagella without any membrane enclosure. Which group do these organisms belong to? A) Bacteria only B) Archaea only C) Eukarya only D) A and B are possible E) None of these
A) Bacteria only
Which of the following molecules do not have any charges on them so that they cannot be separated by gel electrophoresis? There may be more than one answer. A) Carbohydrates B) Triglycerides C)Proteins D)DNA E)RNA F)Carotenoids
A) Carbohydrates, B) Triglycerides, and F)Carotenoids E: Since carbohydrates and most lipids do not have any charges they cannot be separated by gel electrophoresis. Instead, Carbohydrates can be initially purified by centrifugation, and then various techniques such as calorimetric identification of simple vs complex carbohydrates and spectroscopic analysis will give approximate results.
6) Which of the following is the correct sequence of evolution of various life forms from the earliest organism to the latest organism? I. higher plants II. mammals III. bacteria IV. humans A) III, I, II, IV B) I, II, IV, III C) IV, III, I, II D) I, III, II, IV E) II, III, I, IV
A) III, I, II, IV
Which of the following molecules will rapidly diffuse through the phospholipid part of the cell membrane? A) Water B) Glucose C) CO2 D) Salt E) small protein
A) Water and C) CO E: Hydrophobic molecules such as hydrocarbons, non-polar small molecules such as O2 and CO2, and polar small molecules such as water can easily pass through the lipid part of the bilayer. Medium uncharged polar molecules such as glucose, charged ions (such as Na+, Cl-), and molecules (such as nucleotides or amino acids) cannot go through the lipid portion.
Which of the following structures will be abundant in the liver tissues of a person addicted to drugs? A) smooth ER B) lysosomes C) rough ER D) mitochondrion E) nucleolus
A) smooth ER E: enzymes of the smooth ER help detoxify drugs and poisons, especially in liver cells. Detoxification usually involves adding hydroxyl groups to drug molecules, making them more water-soluble and easier to flush from the body. The sedative phenobarbital and other barbiturates are examples of drugs metabolized in this manner by smooth ER in liver cells
You would be wasting your time if you were trying to use a light microscope to see_______ A) viruses B) animal cells C) bacteria D) yeast cells E) chloroplasts F) ribosomes
A) viruses and F) ribosomes E: light microscopy: -frog egg -most plant and animal cells -nucleus -most bacteria -mitochondria only seen by electron microscope: 2nm-100 Um -smallest bacteria -viruses -ribosomes -proteins -lipids seen by both: 1 Um-100 Um -most plant and animal cells -nucleus -most bacteria mitochondria
You are working for CDC and investigating a toxic E. coli contamination in lettuce. Which method(s) would be useful to definitely identify the toxic E. coli?
A. Microscopes can be used only to detect if any bacterial contamination is present and not if they are toxic or not. B. Isolating and culturing such bacteria and looking for markers will identify if they are toxic or not.
B. Compartments in Eukaryotic Cells List 3 reasons as to why eukaryotic cells have so many internal membrane-enclosed structures and suggest how they benefit from these structures. Include specific examples.
A. more metabolic processes happening. e.g. ER B. Maintain unique internal conditions for the specific metabolic reactions, e.g. chloroplast C. Diversity of metabolic functions by different compartments. e.g. lysosome D. Protection of contents inside. e.g. nucleus E. Interconnected structures that allow the transport of molecules between these structures. e.g. vesicles move proteins from ER to Golgi to other structures.
Which of the following is the most rapidly reproducing organisms, based on their simplicity or complexity?
A: Bacteria E: Bacteria being small and without any nucleus or other membrane-bound organelles replicate the most rapidly.
When the pH was increased from 5 to 7 in an in vitro experiment, these structures purified from animal cells stopped digesting their contents. What are these structures? A) smooth ER B) lysosomes C) nucleus D) mitochondria
B)
Which of the following animal cells produce antibodies? A) A cells B) B cells C) T cells D) Stem cells E) Liver cells
B) B cells
Which of the following cells can perform phagocytosis? Choose all that apply. Select all that apply A) Bacteria B) White blood cells C) Plant cells D) Fungal cells E) Skin cells F) Amoeba
B) White blood cells F) Amoeba
1) Which of the above organisms will be able to survive extreme temperatures of up to 90 ̊C? A) Bacteria only B) Archaea only C) Eukarya only D) A and B are possible
B) Archaea only
Which of the following is the correct sequence of plant cell structural layers, beginning with the cytoplasmic side and progressing outward? It may help to draw two adjacent plant cells and the cell walls to answer this question. A) The plasma membrane, middle lamella, secondary wall, primary wall B) Middle lamella, primary wall, secondary wall, plasma membrane, C) The plasma membrane, secondary wall, primary wall, middle lamella D) Primary wall, middle lamella, secondary wall, plasma membrane, E) The plasma membrane, secondary wall, middle lamella, primary wall
B) Middle lamella, primary wall, secondary wall, plasma membrane,
5) Ribosomes are made up of rRNA and ribosomal proteins. Ribosomes have large and small subunits. Where does the assembly of each subunit of ribosome occur in the cell? A) Mitochondria B) Nucleolus C) Endoplasmic reticulum D) Golgi apparatus E) Cell wall
B) Nucleolus E: Here a type of RNA called ribosomal RNA (rRNA) is synthesized from genes in the DNA. Also in the nucleolus, proteins imported from the cytoplasm are assembled with rRNA into large and small subunits of ribosomes. These subunits then exit the nucleus through the nuclear pores to the cytoplasm, where a large and a small subunit can assemble into a ribosome.
If you like to view the cross-section of a mitochondrion, you most likely would use A) a light microscope B) a transmission electron microscope C) a scanning electron microscope D) agarose gel electrophoresis E) a magnifying glass
B) a transmission electron microscope. E: (Shows Structure) TEM shows the contents of a eukaryotic cell. while light microscopy would be able to see a bacteria's mitochondria it wouldn't be able to see eukaryotic mitochondria.
What type of protein is prostogalndin H2 synthase? A) Peripheral B) Integral C) Glycoprotein D) Lipoprotein
B) integral
What could be the main objective of cell fractionation by centrifugation? A) to crack the cell wall of plant cells. B) to separate the components by their weight or density. C) to identify the enzyme 3-D structure D) to determine the charges of various proteins E) to view the structure of cell membranes.
B) to separate the components by their weight or density. Centrifugation is spinning a solution with cellular components at very high speeds to separate the molecules by density. The less-dense stay at the top, denser ones at the bottom.
What type of receptors would bind to the lipid-soluble hormones shown in this Figure? A) G-protein linked receptors B) Tyrosine kinase receptors C) Cytosolic receptors D) Both A and B E) All A, B and C
C) Cytosolic receptors (intracellular receptors) - can do this since they are hydrophobic enough to cross the hydrophobic interior of the membrane. Hydrophobic signaling molecules include steroid hormones and thyroid hormones in animals. Intracellular Receptors are soluble proteins in the cytoplasm or the nucleus. These are specific for a certain type of soluble chemicals that can diffuse through the membrane or lipid-soluble hormones that can pass through the membrane easily.
Refer to the ECG chart segment shown above and choose the point which represents the depolarized state that results in the action potential. A) P B) Q C) R D) S
C) R
Animal viruses infect specific host cells and do not cross the host range. This is because viruses are recognized and allowed inside cells through _______________________ A) Phagocytosis B) Pinocytosis C) Receptor mediated endocytosis D) Facilitated diffusion E) Exocytosis.
C) Receptor mediated endocytosis Receptor proteins in cells are recognized and bound by proteins in viruses which trigger the endocytosis of the virus. The receptor is specific to the viral protein
Which of the following action of cytoskeletal elements, a plant cell will not be able to do? A) Movement of chromosomes during cell division B) Transport of vesicles along microtubules C) Cleavage furrow (pinching in middle of cell) formation during cell division D) Cytoplasmic streaming of chloroplasts
C) Cleavage furrow (pinching in middle of cell) formation during cell division E: The tough cell wall prevents cells from cleaving. E: A. movement of chromosomes happens with microtubules B. transport of vesicles happens with microtubules C) cleavage furrow happens with microfilaments only in animal cells D) streaming of chloroplasts happens with microfilaments
Which organisms will have linear chromosomes with histone proteins bound to their DNA? A) Bacteria only B) Archaea only C) Eukarya only D) A and B are possible E) None of these
C) Eukarya only E: eukarya is the only type with linear chromosomes however eukaryotic and archaea have histone proteins bound to the DNA
Which of the following molecules will be able to cross a synthetic dialysis membrane with a pore size of 100 daltons (AMU) and not through the biological membrane by simple diffusion? A) CO2 B) Starch C) NaCl D) DNA E) O2
C) NaCl
What structures are similar to each other in the list given below? A) Tight junctions and primary cell wall B) Secondary cell wall and anchoring junctions C Plasmodesmata and gap junctions D) Middle lamella and anchoring junctions E) Gap junctions and secondary cell wall
C) Plasmodesmata and gap junctions E: provide cytoplasmic channels from one cell to an adjacent cell and in this way are similar in function to the plasmodesmata in plants
Which of the following molecules are the most essential for cell communication? A) DNA B) RNA C) Proteins D) Lipids E) Polysaccharides
C) Proteins
If you were to genetically engineer a papaya plant that will resist fungal disease, you would like to express high levels of the enzyme _____________ that will degrade the fungal cell wall. A) proteinase B) phosphatase C) chitinase D) cellulase E) lysozyme
C) chitinase E: the fungal cell wall includes chitin (also found in the exoskeleton of insects) so the enzyme that would degrade it is ChitinASE.
2. Since the sodium-potassium pump transports 3 Na+ out and 2 K+ in, it also_______ A) pumps hydrogen ions into the cell. B) pumps hydrogen ions out of the cell. C) contributes to the electrochemical gradient. D) contributes to osmotic pressure in the cell. E) changes the cellular pH.
C) contributes to the electrochemical gradient.
Most of the antibiotics are derived from ______________________ A) Algae B) Bacteria C) Fungi D) Plants E) Animals
C) fungi
Which of the following structures are important for providing energy (ATP) for the cytoplasmic functions in a plant? A) microtubules B) chloroplast C) mitochondrion D) lysosome E) nucleus
C) mitochondrion E: The ATP made by chloroplast is used up in Photosynthesis and not shared by the cytoplasm.
Bacteria and fungi can degrade wood because they can make the enzyme _________________________.
Cellulase E: The cellulose in plant cell walls is degradable by an enzyme called cellulase. which is made by fungi and some bacteria. -Ruminants also harbor bacteria that make cellulase in their rumen to digest cellulose.
Compare and contrast chloroplast and mitochondrion with three common features and three differences. Draw a Table or Venn diagram.
Common features - Double membrane structure • Internal ATP synthesis• From an H+ gradient generated by ETC - has its own DNA and proteins - replicate autonomously • Both are maternally inherited Differences:• -chloroplast is in plants only while mitochondria in all eukaryotes -amino biosynthesis occurs only in chloroplasts while essential amino acids are used up in eukaryotes (animal cells) -major function respiration vs major function in photosynthesis
E. If you are given unlabeled DNA sequences for a particular gene from bacteria, plants, zebra fish, and humans, how will you use such information and based on what you would identify which sequence came from a particular organism and predict their evolutionary relationship?
Compare these sequences with existing DNA sequences from these organisms to match them with the most similar sequences. Closely related organisms will have the least number of differences. For example, human DNA sequences will be closer to zebrafish, than plants than bacteria.
Which of the following signaling mechanism of action does OxyContin directly affect? A) direct contact B) paracrine signaling C) endocrine signaling D) synaptic signaling E) indirect signaling
D) synaptic signaling Oxycontin affects neuronal activity which is synaptic signaling.
Arrange the following sequence of procedures in the proper order in this experiment done to determine proteins present in pea plants during germination. 1. Load the proteins in polyacrylamide gel electrophoresis and separate them 2. Break the cells by grinding them in liquid nitrogen and suspending them in a buffer 3. Select a suitable tissue to isolate proteins expressed only during germination 4. Centrifuge the broken cells to purify proteins from other molecules A) 1,3,2,4 B) 3,2,1,4 C) 2,4,1,3 D) 3,2,4,1
D) 3,2,4,1 E: The first step is to identify where you want the cells from. Then you have to break the cells to retrieve the proteins and centrifuge the components to isolate the proteins. Then you load the gel with the proteins and run it to separate according to size and charge.
Cell Theory in its modern form includes all of the following postulates except __________________ A) All organisms are composed of one or more cells. B) Cells are the smallest living things. C) Cells arise only by division of a previously existing cell. D) All cells contain a nucleus E)Cell is the unit of life. F) All cells need oxygen.
D) All cells contain a nucleus F) All cells need oxygen D->>> Prokaryotic cells don't have a nucleus but instead a nucleotide which doesn't have a double membrane as the nucleus does. F--->> Not necessarily; some cells can be anaerobic or facultatively aerobic based on oxygen levels in the environment. They can survive through glycolysis to form ATP.
Which of the following components of the cell membrane affects selective permeability? A) Phospholipids only B) Proteins only C) Carbohydrates D) Both A and B E) A, B and
D) Both A and B
Freshwater protists such as paramecium maintain homeostasis of their salt concentration by pumping water out of the cell. Which of the following structures would serve this purpose? A) Large central vacuole B) Small central vacuole C) Proton pump D) Contractile vacuole E) Food vesicle
D) Contractile vacuole E: Many unicellular protists living in fresh water have contractile vacuoles that pump excess water out of the cell, thereby maintaining a suitable concentration of ions and molecules inside the cell.
6. Which of the following cytoskeleton elements or associated proteins/structures are not involved in cellular movement or molecular transport? A) Vesicles B) Actin and myosin C) Microfilaments D) Intermediate filaments E) Microtubules
D) Intermediate filaments
How does the double membrane structure of mitochondrion help in its function to make ATP? A) Stopping any molecules to go through the mitochondrion B) Allowing only small molecules to go through the double membrane C) Controlling only polar molecules to go through D) Maintaining conditions within and between the two membranes to allow ATP synthesis E) Allowing only non-polar molecules to go through them
D) Maintaining conditions within and between the two membranes to allow ATP synthesis E: The pH of the mitochondria is very important for ATP synthesis and internal and external conditions need to be monitored closely for optimal functioning.
Which of the following is not a common feature of both chloroplast and mitochondrion? A) Have their own DNA B) Make ATP C) Prokaryotic in nature D) Makes essential amino acids E) Make their own proteins and import some from the cytoplasm.
D) Makes essential amino acids E: Essential amino acids are made only by chloroplasts as we need to consume them in our diet.
Tasmanian tigers are extinct because of hunting by humans but the close relative Tasmanian devils are still alive and thriving well. If you were to use an adult cell's nucleus with intact DNA from a Tasmanian tiger to replace the nucleus of a Tasmanian devil's egg cell and make it produce to a new organism in a surrogate Tasmanian devil's womb, what kind of organism will it make? A) Completely Tasmanian Tiger B) Completely Tasmanian Devil C) A hybrid with 50% of both organisms D) Mostly Tasmanian Tiger with the mitochondrial DNA from the T. Devil E) Mostly Tasmanian Devil with the mitochondrial DNA from T. Tiger
D) Mostly Tasmanian Tiger with the mitochondrial DNA from the T. Devil e: The mitochondrial DNA is maternally inherited as it will come with the egg cell.
We need to consume essential amino acids in our diet because we do not have ______________ that make essential amino acids. A) Mitochondria B) Ribosomes C) Lysosomes D) Plastids E) Glyoxysomes
D) Plastids E: Plastids are only found in chloroplasts and make essential amino acids.
What was the major conclusion from the Urey and Miller experiment? A) Life can be formed from simple chemicals B) Organic molecules come from living organisms only C) Polymers can be formed from monomers D) Simple atoms and molecules can form monomers of biological molecules E) Meteors contain same chemicals as found in living organisms
D) Simple atoms and molecules can form monomers of biological molecules. They created a "primordial soup" using gases found in the atmosphere when the earth was new. They used lightning/electricity as the source of energy to trigger chemical reactions. This proved the point that monomers of complex molecules can be formed under the reducing atmosphere present in the early periods of the earth.
The digestive tract lining contains epithelial (outer lining) cells that do not allow food particles to randomly go inside the body except through specific proteins on their cell membrane. Which of the following structure blocks the random diffusion of food particles between epithelial cells? A) Desmosomes B) Gap junctions C) Plasmodesmata D) Tight junctions E) Cell wall
D) Tight junctions E: tight junctions establish a barrier that prevents leakage of extracellular fluid across a layer of epithelial cells. Fuse 2 cell membranes through integral membrane proteins (prevents any solutes from moving between the two cells)
When the cell's membrane potential reaches +30 mV, what should happen to restore the membrane potential to become -70 mV? A) Allow K+ to leave the cell and Na+ to come in B) Transport Cl- to outside C) Transport both Na+ and K+ inside D) Transport K+ to outside
D) Transport K+ to outside since K+ is a cation when it leaves the cell the inside will become more negative.
Active transport is used primarily to transport small molecules across membranes __________________________. A) down their concentration gradients. B) down their electrical gradients C) against their electrical gradients. D) against their concentration gradients. E) all are correct
D) against their concentration gradients.
What are the barriers for glucose to enter a bacterial cell from the medium? A) plasmamembrane --> cell wall --> capsule B) plasmamembrane --> capsule -->cell wall C) capsule --> plasmamembrane --> cell wall D) capsule --> cell wall --> plasmamembrane E) cell wall --> capsule --> plasmamembrane
D) capsule --> cell wall --> plasmamembrane
If someone is addicted to Oxycontin, as shown below, which of the following enzymes and structures would try to detoxify them? A) cytochrome p450, lysosomes B) cytochrome p450, rough ER C) lysoszyme, mitochondrion D) cytochrome p450, smooth ER E) lysozyme, smooth ER
D) cytochrome p450, smooth ER
When freshwater plant cells are placed in sea water the cells will __________________________ A) absorb water, swell, and burst. B) become turgid with the cell wall bulging out. C) become flaccid with stable cytoplasm inside the cell wall. D) get plasmolyzed with water from cytoplasm leaking out. E) be stable with the same solute concentration of solutes inside and outside
D) get plasmolyzed with water from cytoplasm leaking out. E: sea water plant cells placed in freshwater will absorb water, swell, and Burst so the opposite will happen when freshwater plants are placed in seawater it will plasmolyze. -Plasmolysis is when the cytoplasmic fluid is leaking out of the cell. This can happen when the cell goes into a hypertonic solution, such as seawater. since water has a high concentration of salt which makes water diffuse to a high concentration out of the cell.
The major differences in the function of rough ER compared to smooth ER is to __________________ A) make steroid hormones B) synthesize phospholipids C) detox drugs D) make proteins E) make carbohydrates
D) make proteins e: the other answer choices smooth Er can do but they can't make proteins since they don't have any ribosomes unlike the rough ER. which has ribosomes attached to them and make proteins that are bound for membrane or secretion.
Which of the following organelles would be essential for making and detoxifying active oxygen species? A) Smooth ER B) Lysosomes C) Rough ER D) Peroxisome E) Nucleolus
D) peroxisome E: peroxisomes are responsible for lipid degradation and detoxification of active oxygen species E: Peroxisomes contain enzymes that remove hydrogen atoms from certain molecules and transfer them to oxygen (O2), producing hydrogen peroxide (H2O2
The first organic molecule(s) before life started on earth was/were most likely to be ______________ A) polypeptides B) RNA C) DNA D) simple organic compounds such as amino acids and sugars E) polysaccharide
D) simple organic compounds such as amino acids and sugars e: After cooling the reaction products, Miller and Urey noticed that simple organic molecules including urea, organic acids, simple sugars, and amino acids were formed from this setup. This proved the point that monomers of complex molecules can be formed under the reducing atmosphere present in the early periods of the earth. so basically simple organic molecules were proven to be able to form more complex molecules such as RNA, DNA, etc. with the atmosphere present in early periods.
In agarose gel electrophoresis, DNA or RNA fragments migrate towards ___________ end of the gel plate because of their____________. A) the neutral..... charge B) the anode ..... size C) the cathode ..... charge D) the anode ..... charge E) the neutral ..... size
D) the anode ..... charge E: The negative charges on the DNA or RNA (due to the phosphate groups) make them migrate towards the anode (+) through tiny pores in the gel, made of agarose or polyacrylamide
Arrange the following processes in the order in which they evolved from oldest to latest. 1. Photosynthesis 2. Respiration 3. Neuron signaling Arrange the following processes in the order in which they evolved from oldest to latest. 1. Photosynthesis 2. Respiration 3. Neuron signaling A)1, 2, 3 B)1, 3, 2 C)3, 2, 1 D)2, 1, 3 E)2, 3, 1
D)2, 1, 3 Respiration is a property of all living organisms including bacteria - the oldest life form, followed by photosynthesis common in cyanobacteria & plants, and the nervous system is common in animals which evolved last. respiration is seen in all living organisms such as bacteria which is the oldest life form then comes plant life which requires photosynthesis then neuron signaling which is seen in the animals, the newest life form
Which of the following is the correct sequence of events in the origin of life? I. Synthesis of organic monomers II. Formation of prebiotic structures III. Synthesis of organic polymers IV. Formation of reproducible cells A)III, II, I, IV B)I, II, IV, III C)IV, III, I, II D)I, III, II, IV E)II, III, I , IV
D)I, III, II, IV E: Monomers can form polymers which are required for prebiotic structures. Reproducible cells are highly complex and come last in the sequence of events Atoms > Molecules > Monomers > > Macromolecules > > Protobionts (natural) (reducing conditions) (polymerization on a solid support) (self-assembly). >> reproducible cells
Which of the following is the right order of evolution of the following organisms? I) Plants II) Rodents III) Humans IV) Bacteria A)II, III, IV, I B)I, IV, II, III C)IV, II, I, III D)IV, I, II, III E)IV, III, I, II
D)IV, I, II, III -Simple *bacteria evolved about 4 billion years ago and lived on chemicals (chemotrophic). - The photosynthetic cyanobacteria (autotrophic), originated around 2.5 billion years ago. They were able to fix carbon dioxide into simple sugars and release oxygen into the atmosphere. -This made the atmosphere rich in oxygen. Around 2 billion years ago, the oldest unicellular eukaryotic organisms started to appear and about 1 billion years ago the multicellular organisms appeared. -The last 500 million years saw an explosion of various life forms in both plants and animals. The current human genus and species evolved within the last 100, 000 years.
Which of the following statements is/are true about the origin of life on earth? A)All life forms were created by some superhuman powers B)Life started with an aliens spaceship bringing the first life forms C)Water bubbles in the air combined with minerals and formed life D)Simple molecules combined to make larger molecules and eventually the ancestral cells E)All life forms existed as it is present today ever since the earth was formed
D)Simple molecules combined to make larger molecules and eventually the ancestral cells e: Chemical evolution of first life forms from basic molecules is the most plausible way. Some steps of this process have been proven by scientific experiments.
Five dialysis bags (the synthetic membrane that do not allow glucose to go through) with various contents were placed in beakers with aqueous solutions. The bags were weighed before and after placing them in the beaker for 24 hours. Bag Dialysis Bag Content Beaker content A 0.5 M glucose Water B 0.75 M glucose 0.5 M glucose C 1.0 M glucose Water D 0.75 M glucose 1.0 M glucose E Water 1.0 M Glucose Which bag will lose the most amount of weight (net) after 24 hours incubation in the respective solutions? A) B) C) D) E)
E) water diffuses from low to high concentrations so water will diffuse out of the bag to the beaker content which has a high concentration of glucose.
Which of the following actions represents direct contact mechanism of cell signaling? A) Movement of chromosomes during cell division B) Transport of vesicles along microtubules C) Volatile molecules secreted by plants D) Insulin secreted by panareas traeling to other parts of a body E) Gap junctions allowing small signal molecules to go through
E) Gap junctions allowing small signal molecules to go through
Ion channel proteins are always ____________________________ A) glycoproteins with oligosaccharide attached B) lipoproteins with lipid attached C) soluble proteins in the cytoplasm D) integral membrane proteins E) peripheral membrane proteins
E) integral membrane proteins E: transport proteins/ channel proteins function by having a hydrophilic channel that certain molecules or atomic ions use as a tunnel through the membrane. they are integrated into the membrane to allow for these molecules to move through. ex: ion channel proteins, aquaporins, carrier proteins-change shape in a way that shuttles them across the membrane -specific for the substance it moves along the membrane. Very selective
2. Which of the following pairs is mismatched? A) smooth ER: lipid hormone biosynthesis B) ribosomes: protein synthesis C) central vacuole: plants D) ER membrane: vesicle E) Golgi apparatus: DNA replication
E) Golgi apparatus: DNA replication
What will happen if the segment of DNA coding for the target sequence is deleted from a gene encoding a protein located in lysosomes? A) Its mRNA will not be made in the nucleus. B) Its mRNA will not be processed properly. C) Protein synthesis will not happen for this mRNA. D) Once the protein is made, it will return to the nucleus. E) It will not reach the target site, the lysosome.
E) It will not reach the target site, the lysosome. E: The target sequence is only one part of the protein and its absence will not allow the protein to reach its target, Lysosome.
Which of the following pathway is the most probable pathway for secretory proteins that are glycosylated along the way? A) ER → Vesicle → nucleus → lysosomes → plasma membrane B) Nucleus → Smooth ER → Golgi apparatus → plasma membrane C) Golgi Apparatus → vesicles → lysosomes → plasma membrane D) Ribosomes → lysosomes → Golgi apparatus → plasma membrane E) Rough ER → vesicles → Golgi apparatus → plasma membrane
E) Rough ER → vesicles → Golgi apparatus → plasma membrane E: secretory proteins are synthesized from rough ER then travel through transport vesicles to Golgi apparatus to the plasma membrane
Which of the following structures are important for maintaining water pressure and movement of water in a tall plant? A) Desmosomes B) Plasma membrane C) Plasmodesmata D) Tight junctions E) Cell wall
E) cell wall E: Provides a rigid structure that can create an osmotic pressure to push water to a cell with less water
The more recent medicines such as ibuprofen (Motrin) and naproxen (Aleve) unlike aspirin do not cause bleeding but reduces inflammation because A) these new medicines are less specific to bind to the ion channels. B) these new medicines are more specific to bind to the ion channels. C) these new medicines do not enter the ion channels but physically block them. D) of both the possibilities A and C E) of both the possibilities B and C
E) of both the possibilities B and C
All the following are present in the biological membrane except_____________________ A) phospholipid B) sterols C) integral proteins D) oligosaccharides E) polysaccharides
E) polysaccharides E: Polysaccharides are present in cell wall and not in cell membrane.
3. Damage in mitochondrial DNA will have the most effect on _______________ A) glycosylation and myristylation B) photosynthesis and amino acid biosynthesis C) intracellular communications D) intercellular communications E) respiration and ATP synthesis
E) respiration and ATP synthesis
ions cannot easily go through lipid part of cell membranes because ____ A) the bilayer is hydrophilic inside. B) the ions are charged and hence need lipid layer to go through. C) lipids allow only small, polar and charged molecules. D) ion movement always need ATP for energy. E) they are charged and hence need specific ion channels.
E) they are charged and hence need specific ion channels. E: Ions are charged, and consequently, they are hydrophilic and cannot associate with the lipid portion of the membrane. Ions must be transported by carrier proteins or ion channels.
Plants can defend against grazers by producing ______________________ A) carbohydrates B) proteins C) lipids D) hormones E) secondary metabolites
E)secondary metabolitesvolatile and organic compounds that smell or taste bad.
As a cell begins the process of dividing, its chromosomes become shorter, thicker, and individually visible in an lM (light micrograph). Explain what is hap- pening at the molecular level.
Each chromosome consists of one long DNA molecule attached to numerous protein molecules, a combination called chromatin. As a cell begins division, each chromosome becomes "condensed" as its diffuse mass of chromatin coils up.
How does a larger cell compensate for the reduced amount of surface area as the cell volume increases?
Folding and compartmentalization
What types of symptoms would show in an individual with a defective mitochondrial genes?
Lack of energy E: Since mitochondria provided energy an individual with a defective mitochondrial gene would have a lack of energy.
Draw a flow chart of how a protein is made starting from its genes in the nucleus and trace the pathway it is modified along the way and imported into peroxisome, lysosome, and vacuoles. Mark the function of such proteins in the respective structures.
Nucleus (DNA > mRNA > mRNA processing) > Cytoplasm (ribosomes make protein signal peptide) > Signal Recognition Particle (SRP) helps navigate to rough ER where the protein synthesis is completed > Vesicles carry this protein to Golgi apparatus (where it is modified with glycosylation) and packaged in vesicles to be transported to various structures based on its target sequence.
What type of information would be essential for the proteins to reach their destination?
Signal peptides are recognized by SRP proteins and they help the new protein being made navigate to rough ER. The target sequence in the proteins will determine which target organelle they will be delivered to through vesicles moving on the microtubule.
List two (one polar and one non-polar) in each of small (1-100 Da), medium (100-1000 Da) and large (>1000 Da) molecules and write the mechanism that would allow such molecule to be transported through a biological membrane similar to the one you have drawn.
Small polar: H20, Ca, Na, K, H (facilitated diffusion, active transport). -H2O -Na+ Small non-polar: CO2, O2, CH4 (simple diffusion). -CO2 -O2 Medium polar: - amino acids, - glucose. (facilitated diffusion, active transport). Medium non-polar: (dissolve in lipids) -fats, -steroids (simple diffusion). Large polar: polysaccharides, DNA, RNA, soluble proteins Large non polar: -large lipid bodies, membrane proteins, insoluble fibers
What role do ribosomes play in carrying out genetic instructions?
The genetic messages are translated by the ribosomes, which are involved in the process of gene expression. It performs the conversion of DNA into mRNA to form proteins.
While you swim in the pool, you do not absorb water and swell because the skin has_________________________.
Tight junctions E:tight junctions between skin cells make us water tight
A scientist wants to isolate ribosomal RNA from other RNAs of the cell. Which of the following techniques would be most suitable for this purpose? a. a powerful bright field microscope to differentiate all types of RNA b. centrifuging a homogenized cell extract to a specific speed. c. conduct scanning electron microscopy of ribosomes making proteins d. agarose gel electrophoresis of all cell contents to separate only ribosomal RNA. e. scanning electron microscopy of all cell contents to identify only ribosomal RNA
d. agarose gel electrophoresis of all cell contents to separate only ribosomal RNA.
1. How will you design drugs that would easily go through the cell membrane, and some that will not easily enter through the cell membrane?
drugs that will easily go through the membrane will be small, non polar, and uncharged drugs that won't be easily able to go will be larger, polar, and charged
Name three types of evidence to study evolution.
fossils, DNA, structural similarities e: Using both fossil evidence and DNA sequence comparisons, we can establish that life evolved from simple to complex forms on earth
Describe the molecular composition of nucleoli and explain their function.
nucleoli consist of DNA and ribosomal RNA (rRNA) made according to its instructions, as well as proteins imported from the cytoplasm. together, the rRNA and proteins are assembled into large and small ribosomal subunits.
What factors affect the simple diffusion of molecules in aqueous surroundings?
polarity and size
Where do the rRNA and ribosomal proteins synthesis take place, what processes made them and where do the subunits get assembled? Organize this information into a flow chart or concept map.
rRNA: in nucleolus, transcription, subunits assembled in nucleus ribosomal proteins:in cytoplasm, translation, subunits assembled in the nucleus
List four different types and examples for each of cell communication processes happening right now in your body. Predict what type of receptors and signaling mechanisms are involved.
synaptic signaling: neurotransmitters nerve cells allowing you to see -oxytocin paracrine signaling: spinal cord development endocrine signaling: testosterone
