Before the invention of modern abrasive cleansers, which feature of horsetails was used by humans to scrub pots and
polish metals?
a. waxy spores
b. silica-rich leaves
c. lignin-rich leaves
d. cones at the tips of their stems
e. silica-rich stems
ANSWER: e
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Vast numbers of microorganisms are being genetically characterized without culturing them in the laboratory today through ________.
A. metagenomic sequencing B. mass spectrometry and proteomics C. column chromatography D. polymerase chain reaction
Jamal and his friends order some chicken at a new restaurant, but they immediately notice that it tastes bitter
Jamal knows that everyone is really hungry, but he tells them not to eat another bite because the bitterness could potentially mean that ________. A) the meal contains too much protein B) the food may be poisoned or spoiled C) there is probably too much vitamin C D) unripe fruit was used in the breading around the chicken
A newly identified bacterial pathogen has been shown to cause disease in humans, disrupting the production of some proteins by interfering with the function of the endoplasmic reticulum of liver cells. Under specific growth conditions, this bacterial strain secretes a protein that appears to be responsible for the pathology of the disease. This protein is composed of two polypeptide chains, one of which binds to a receptor on the surface of liver cells, stimulating the uptake of the protein by endocytosis. Once inside the cell, the other polypeptide component interferes with the activity of ribosomes bound to the endoplasmic reticulum. This bacterial protein will most likely be classified as a/an __________.
A) superantigen B) A-B toxin C) invasin D) membrane-disrupting toxin E) bacterial kinase
Cell extension involves
A. water leaving the central vacuole. B. expansion of cellulose microfibrils. C. loss of water. D. enzymes that produce polysaccharides. E. low acidic condition.