Cell: The Unit of Life Questions and Answers

A scientist wants to study the kinetics of a specific membrane protein. They ligate the DNA coding region of the protein to the DNA coding region for GFP and introduce the DNA into cells. A day or two later, they observe the cells under the microscope and they are fluorescing green. They then shine a laser at a region of the cell repeatedly (or continuously) that region loses its fluorescence. They monitor a separate region of the cell and find that fluorescence never decreases in that area. What is the full name of the technique that they performed? What can they conclude from their result? a) What is the full name of the technique that they performed? The technique is known as Fluorescence Loss in Photobleaching (FLIP). b) What can they conclude from their result?

You have discovered a new cytosolic protein that binds to KKXX sequences, preventing these sequences from interacting with other proteins. What is the most likely function of this new protein? It prevents the movement of proteins from the Golgi apparatus to the endoplasmic reticulum. It prevents the movement of proteins from the Golgi apparatus to the early endosome. It prevents the vesicle uncoating that occurs after vesicle formation. It prevents the binding of KDEL containing proteins to KDEL receptors under acidic conditions.

A new graduate student is asked to add a nuclear localization sequence (NLS) to the C-terminus of a secreted protein in order to localize the protein to the nucleus. What would be the most appropriate response? Great idea, we can now see if this protein can function in the nucleus. Great idea, but we should remove the endoplasmic reticulum signal sequence. Great idea, but the NLS will act as a transmembrane domain. This will not work since the NLS will be cleaved off the protein.

In the presence of high glucose and high lactose, what occurs at the E. coli Lac operon? Operon expression is OFF because there is a repressor protein and there is no activator protein. Operon expression is OFF because there is no activator protein. Operon expression is OFF because there is a repressor protein. Operon expression is ON because RNA polymerase can transcribe with high initiation efficiency.

Which ONE of the following forms of transport would you expect to be the fastest for a small ion? Passive diffusion Transport by a membrane protein driven by ATP hydrolysis Facilitated transport via a beta barrel protein Active co-transport using another ion

In this Lab, we saw three bands in our gel from our bacterial rRNA, how would this differ if we had used isolated human rRNA? 2 marks Since human rRNA is larger than bacterial rRNA, larger bands would appear on gel electrophoresis.

What is a common feature of cellular membranes? Membrane fluidity is maintained by protein enzymes. They require carbohydrates for solubility in water. They provide an environment to denature proteins. They can create regions of the cell with specialized functions.

Which scientists are credited for the events described in the development of the cell theory? used the word cell for the structures he observed when he examined a piece of cork under the microscope. was the first person to observe a living cell in a drop of pond water.

The electrochemical gradient of an ion is composed of its concentration gradient and the pH gradient how permeable the membane is to that ion the membrane potential whether there are open channels for that ion

Which of the following would not be a stage in the cycle of domestic violence? The Tension Building Phase The Bargaining Phase The Acute Battering Episode Phase The Honeymoon Phase

In models of logistic population growth, the population growth rate slows dramatically as N approaches K. only density-dependent factors affect the rate of population growth. new individuals are added to the population as N approaches K. carrying capacity is never reached.

Substances that are naturally produced by certain microorganisms that can inhibit or destroy bacteria antibiotics narrow-spectrum drugs. semisynthetic drugs synthetic drugs broad-spectrum drugs. called

Which of the following is NOT a factor in the movement of water into tissues? salinaity gradient fluid pressure active transport diffusion osmotic gradient

The operation of the sodium-potassium "pump" moves sodium and potassium ions into the mitochondria. sodium and potassium ions out of the cell. sodium ions out of the cell and potassium ions into the cell. sodium ions into the cell and potassium ions out of the cell. sodium and potassium ions into the cell.

In a typical nerve cell, the nucleus is found in the cell body. synapse. axonal region. synaptic terminals. dendritic region.

Which of the following is not characteristic of the synaptic vesicle? Select the best answer. also known as the cell body contains neurotransmitters contained in terminal buttons

Extracellular digestion means that: the digestion occurs in the host the digestion occurs inside the alimentary canal the digestion is conducted by macrophages in the extracellular matrix the digestion occurs out of the body the digestion occurs by phagocytosis

Finding cells when examining various types of tissues under the microscope helped scientists agree on the first principle of cell theory. Which of the following is the first principle of cell theory? a) Cells and compartments are equal b) Cells can be broken down into smaller pieces c) All organisms are made up of cells d) Plant and animal cells are the same

A cytologist finds that antibiotic X interferes with the ability of the ribosomes in bacterial cells to move. What step would likely be affected if the bacteria are exposed to this antibiotic? The polypeptide chain will be shorter than the normal. Small, broken chains of polypeptide will be formed. An undesired polypeptide chain with the wrong amino acid sequence will be produced. No proteins will be synthesized.

When a bacterium has a viral DNA incorporated into its genome, the bacterium becomes a ... provirus prophage temperate cell lysogenic cell lytic cell

A mutated tumor suppressor gene... A. might cause cancer B. can lead to mutations in the DNA C. might favor viral infections D. correct errors that arise when cells duplicate their DNA prior to cell division E. All of the above

Are the following statements true for yeasts, molds, or both? A. Cells contain membrane-enclosed organelles B. Grow preferably at 37C C. Reproduce by sporulation D. Unicellular E. Composed of hyphae F. Cells reproduce by budding

Where is the most unlikely place in the cell to find a ribosome? Group of answer choices On the exterior surface of a cell's plasma membrane. Free floating in the cytosol In the mitochondria, making mitochondria specific proteins from mitochondrial DNA. Embedded in the endoplasmic reticulum's membrane

The fluidity of the plasma membrane can be changed by everything except... Group of answer choices ratio of saturated vs monounsaturated phospholipids addition of cholesterol changing the temperature of the environment the cell is in the amount of glucose crossing the membrane

A frame-shift mutation might generate a.... longer protein shorter protein a protein with many incorrect amino acids a normal length protein Any of the above

What happens to a microorganism that is placed at a temperature below the Minimum Growth Temperature? A. The enzymes denature and the microbes die B. Microorganisms stop growing (i.e. reproducing) C. The enzymatic activity is too low because it decreases at low temperature A and C B and C

In the stationary phase of the bacterial growth curve... bacteria stop dying bacteria stop reproducing the rate of bacterial growth equals the rate of bacterial death The rate of bacterial death is higher than the rate of bacterial growth Bacteria completely run out of food

The temperature at which microbes reproduce the fastest is... 37C 25C 60C at their optimum growth temperature at their maximum growth temperature

You are the first scientist to study the signaling pathway that regulates your favorite animal cell behavior. You discover that phospholipase C, DAG and IP3 are essential components of the signaling pathway. From this information, what can you conclude about the receptor for this pathway? It can only be a nuclear receptor This information does not support any of these conclusions. It could be a G-protein coupled receptor OR a receptor tyrosine kinase. It can only be a receptor tyrosine kinase. OIt can only be a G-protein coupled receptor.

Which one of the following is not a second messenger? Briefly explain why it isn't considered a second messenger (you will want to define second messenger during your answer!) Options: • Nitric oxide (NO) • Diacylglycerol (DAG) • MAP kinase (MAPK) • Ca²+ • cyclic GMP (CGMP)

For a body surface to be a respiratory surface, it must be thin and moist Obe thick and moist be internal be dry and covered with hair be moist and glandular

Urea is the primary nitrogenous waste product of most aquatic invertebrates. insoluble in water. more toxic to human cells than ammonia. the primary nitrogenous waste product of most birds. the primary nitrogenous waste product of humans.

2. Synthesis of repressible enzyme such as the ones in the tryptophan Operon is stopped by the... A. end product binding to the promoter B. substrate binding to the repressor. C. corepressor binding to the operator. D. corepressor-repressor complex binding to the operator. E. none of the above.

The complement system of blood proteins acts to lyse foreign cells and viruses True False

Small foreign molecules that are too small by themselves to elicit an immune response may be attached to a host macromolecule to generate an antigenic response True False

Ultraviolet radiation is a type of electromagnetic energy. True False

During fermentation through the ethanol pathway, the NAD+ and acetaldehyde half reactions must be paired. Which statement(s) is are true about this coupled reaction? Explain your reasoning for each answer. A. Acetaldehyde will have the highest electron affinity B. NADH will be oxidized when ethanol accepts its electron C. NAD+ will be reduced in the spontaneous reaction D. acetaldehyde will be reduced and NADH will be oxidized

You have been hired by a new biotechnology start up and placed in charge of cloning their new "miracle" gene. Describe the steps (in order) you would follow to produce some transgenic bacteria (GMO) so the company can start manufacturing their new product and get it on the market. What vector would you use and what enzymes? How would you identify and isolate the transformed cells?

Which of these is NOT a use for DNA fingerprinting? A. Match organ donors with recipients in transplant programs B. Differentiating between identical twins C. Detect bacteria and other organisms that may pollute air, water, soil, and food D. Identify endangered and protected species as an aid to wildlife officials E. Establish paternity and other family relationships

What are the interactions involved in each level of structure of proteins?

Which objective should you always use to observe bacteria? Scanning objective 4X Low power 10X High power 40X Oil-immersion objective 100X

Which step of the Gram stain is considered to be the most critical? Decolorizer Mordant Counterstain Primary stain

Acid-fast organisms appear__ in color when examined microscopically because they retain the primary dye blue; methyl blue red; carbolfuschin purple; crystal violet blue; crystal violet pink; safranin

Would it be acceptable procedure for you to substitute the Gram stain decolorizer for the acid-alcohol decolorizer used in Acid Fast Stain? No because acid-alcohol would decolorize both Gram-positive and Gram-negative bacteria and, thus, it would not be possible to differentiate between them No because the decolorizer from the Acid Fast Stain might dissolve the bacteria Yes, because they both use alcohol No because the acid would dehydrate the Gram-positive cell wall Yes, because they are both decolorizers

At which temperature a thermophile organism grows the fastest? At about 90C At about 60C At 37C At about 50C At about 70C

Which characteristic of SARS-Cov-2--the virus that causes COVID-19-- make it more susceptible to be inactivated by heat? It is Gram-negative It evaporates with heat It is enclosed within a lipid membrane and heat denature the membrane proteins It is not susceptible to heat

You culture an unknown bacteria at 25C and found that they were able to grow at that temperature. How would you classify the bacteria? a. Psychrophile b. Psychrotroph c Mesophile a or b; it cannot be determined b or c; it cannot be determined

Gram-negative bacteria are generally more resistant to chemical agents than Gram- positive bacteria because Gram-negative have... the Lipid A an outer membrane that provides extra protection a thick peptidoglycan that provides protection a thin peptidoglycan Gram-negative bacteria have a thin peptidoglycan but it does not help to protect them against chemical agents a very thick cell wall

Which sentence below is an example of "Narrative Writing"? A. To create the perfect flavor in your lobster bisque soup, you will need to purchase ten ingredients. B. Here is a list of the most successful composers from 1900 to the present. C. My unexpected trip around the world began in a most peculiar way -- an anonymous phone call.

A buffer resists change to Hydrogen or hydroxyl ion increase. True False