BIOL 1406 exam 2

a cell has the following molecules and structures: enzymes, DNA, Ribosomes, plasma membrane, and mitochondria. it could be a cell from

Nearly any eukaryotic organism

which of the following characteristics, structures, or processes is a common to both bacteria ad viruses (select all that apply)

Nucleic acids Proteins

H1N1 flu is a highly contagious viral infection caused by the influenza A (H1N1) virus. The symptoms of H1N1 are listed in the box. An antiviral agent such as Tamiflu® administered within 48 hours of the appearance of symptoms can reduce the severity of the illness. Why is it important to administer an antiviral agent to an infected person within 48 hours of the appearance of symptoms?

The H1N1 virus replicates quickly

the cell membranes of antarctic ice fish might have which of the following adaptations

a high percentage of polyunsaturated fatty acids

In order to be able to remain latent (dormant) in an infected live cell, herpes simplex virus (HSV) must be able to shut down what process

apoptosis of a virally infected cell

the presence of cholesterol in the plasma membranes of some animals

enables the membrane to stay more fluid more easily when cell temperature drops. enables the membrane to stay less fluid when cell temperature increases

which of the following can be effective in preventing the onset of viral infection in humans?

getting vaccinated.

the difference between pinocytosis and receptor - mediated endocytosis is that

pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor- mediated endocytosis offers more selectivity

pancreatic cells, like the one shown below, produce a lot of protein digesting enzymes If you were able to examine a pancreatic cell under an electron microscope, what type of organelle would you expect to see a lot of?

rough endoplasmic reticulum

match the organelle to the phrase or sentence that describes it best. Each choice may be used once, more than once , or not at all.

see picture

a primary objective of cell fractionation is to

separate the major organelles so that their particular functions can be determined.

What kinds of molecules pass through a cell membrane most easily?

small and hydrophobic

In the 1880s, louis pasteur developed a method of weakening viruses. the weakened viruses could be injected into healthy individuals. how is this method effective in fighting viral diseases?

the immune system develops antibodies in response to the weakened viruses.

Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. Which cellular organelle must be involved in this condition?

the lysosomes

Which line in the graph represents the bag that contained a solution isotonic to the 0.6 M solution at the beginning of the experiment?

C

referring to the graph above, which line in the graph represents the bag with the lowest initial concentration of sucrose?

E

As a cell grows, its plasma membrane expands. which of the following processes is involved in this growth?

Exocytosis

the HIV virus attacks only a certain type of white blood cells, and not other cell types. why?

HIV receptors are not found on the other cell types

the cellular process known ass the sodium-potassium pump was discovered in the 1950s by jens christian skou, a danish scientist. This process is a form of active transport that moves three sodium ions to the outside of a cell for every two potassium ions that it moves into the cell. which of these best explains why energy is needed for active transport.

Ions are moved against the concentration gradient

Electronic Microscopes are very powerful and can see smaller images than a light microscope. What is one advantage, however, of light microscopy over the electron microscopy?

Light microscopy allows one to view dynamic processes in living cells.

which of the following types of molecules are the major structural components of the cell membrane?

Phospholipids and protiens

as a biologist working on your PhD thesis, your research focuses on the endocrine system; specifically the production of steroids in the body such as testosterone, estrogen, and cholesterol. what organelle is a particular importance to your research as it is primarily involved in the synthesis of these steroids?

Smooth endoplasmic reticulum.

antibiotics are used to treat bacterial infections. the overuse of antibiotics, however, has caused bacterial resistance to these antibiotics to increase. Now there are so called "super-bugs", which are bacterial infection, specifically the bacterium Escherichia coli. What type of virus must be used in your research?

T4 phage virus

the nuclear lamina is an array of filament on the inner side of the nuclear membrane. if a method were found that could cause the lamina to fall into disarray, what would you expect to be the most likely immediate consequence?

a change in the shape of the nucleus

You isolate an infectious substance capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, viroid, or prion. You have four methods at your disposal to analyze the substance and determine the nature of the infectious agent.

culturing the substance by itself on nutritive medium, away from any plant cells.

Males afflicted with Kartagener's syndrome are sterile because of immotile sperm, and they tend to suffer from lung infections. what is the most likely defect being caused by this genetic disease?

defects in the microtubule-based movement of cilia and flagella.

at puberty, an adolescent female body changes i both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogen and other steroid hormones. How can one hormone, such as estrogen, mediate so many others?

estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding.

the diagram shows cellular activity across a cell membrane which two processes does this diagram most directly model

homeostasis and transport of molecules

If scientists are trying to use what they know about HSV to devise a means of protecting other people from being infected, which of the following would have the best chance of lowering the number of new cases of infection?

interference with new viral replication in preexisting cases.

Cyanide is a deadly poison. When cyanide enters the body it binds to at least one molecule involved in producing ATP. If you were to examine the cells of a person who had been exposed to cyanide, most of the cyanide would be found within the

mitochondria

Emerging viruses arise by

mutation of existing viruses, the spread of existing viruses to new host species, and the spread of existing viruses more widely within their host species.

in a animal cell, DNA may be found

only in the nucleus and mitochondria

zellweger sydrome, also called cerebrohepatorenal syndrome, is a rare congenital disorder characterized by the inability to break down very long chain fatty acids (VLCFA) and branched chain fatty acid (BCFA). The organelle that is defective in these individuals is also responsible for the removal of hydrogen atoms in alcohol (thus metabolizing it). Which organelle is defective in individuals with zellweger syndrome.

peroxisome

i humans, viral DNA that is integrated into the host genome is called a

provirus

which of the following do prokaryotic and eukaryotic cells both contain

ribosomes cell walls DNA plasma membrae

insulin is a protien synthesized in the cells of the pancreas and then transported to the plasma membrane where it enters the blood stream. Which of the following summarizes the pathway for insulin through a pancreatic cell?

rough ER -> golgi-> vesticle ->plasma membrane

Some students used vinegar to dissolve away the shells of three eggs and used these eggs as models of human red blood cells. The students observed the changes in the eggs when they were placed in different solutions.Which statement best describes the role of the cell membrane in this model?

the cell membrane allows water to enter and leave the cell.

Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a .15 m salt solution become limp and soft. From this we can deduce that

the fresh water is hypotonic ad the salt solution us hypertonic to the cells of the celery stalks

Models of the human immunodeficiency virus (HIV) and an animal cell are shown below. What is the difference in the function of the glycoprotein structures of an HIV virion and the cilia of an animal cell?

the glycoprotien structures are used for attachment, and the cilia are used to move fluids surrounding the cell.

a researcher lyses (breaks open) a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV) . the cell contents are left in a covered test tube overnight. the next day this mixture is sprayed on tobacco plants. which of the following would be expected to occur?

the plants would develop the typical symptoms of TMV infection.

if the paramecium is the placed in a hypertonic environment , which of the following will occur?

water will defuse out of the paramecium.