An instrument that magnifies slight differences in the refractive index of cell
ID: 83106 • Letter: A
Question
An instrument that magnifies slight differences in the refractive index of cell structures is called a(n) _____ microscope. a. electron b. fluorescence c. phase-contrast d. densitometric The term used to describe bacteria that are roughly spherical shaped is _____ a. vibrio b. coccus (cocci) c. bacillus (bacilli) d. Spirilla Which of the following processes can be used to bring nutrients into a cell against a concentration gradient? a. Facilitated diffusion b. Active transport c Passive diffusion d, none of the above Endospores are very resilient to hostile environments since a. they have layers of proteins, lipids, other complex compounds to protect them. b. they are smaller with beneficial surface to volume ratios. c. they contain special modifications to macromolecules absent in other life forms. d. none of the above What property does archaeal and bacterial ribosomes share? a. Both are enclosed in membranes. b. Both have 40S and 60S subunits. c. Both have 30S and 50S subunits. d. Both have DNA in the active sites. NAM (N-acetylmuramic acid) in bacterial peptidoglycan units is made up of a. Lipid b. Protein c. Carbohydrates d. Minerals The lipopolysaccharide (LPS) that is found in the outer membrane of gram negative bacteria is also known as a. murein. b. exotoxin. c. teichoic acid.Explanation / Answer
11. Phase contrast microscopy takes advantage of minute refractive index differences within cellular components and between unstained cells and their surrounding aqueous medium to produce contrast in these and similar transparent specimens. So (c)
12. A coccus (plural cocci) is any bacterium that has a spherical, ovoid, or generally round shape. So (b)
13. To move substances against a concentration or electrochemical gradient, a cell must use energy. Active transport mechanisms do just this, expending energy (often in the form of ATP) to maintain the right concentrations of ions and molecules in living cells. In fact, cells spend much of the energy they harvest in metabolism to keep their active transport processes running. For instance, most of a red blood cell’s energy is used to maintain internal sodium and potassium levels that differ from those of the surrounding environment. So (b).
14. Bacteria endospores are made up of keratin. Keratin is the protein that protects epithelial cells from damage or stress. So (a).
15. Both are 70s and have 30sand 50s subunits. So (c)
16. N acetylmuramic acid is the predominant of sialic acid an a monosaccharide. So (c).
17. Lipopolysaccharide also known as endotoxin.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.