Griffith, a British microbiologist, used bacteria and mice to demonstrate the process of transformation. During transformation,
A. a bacterial chromosome produces an exact copy of itself.
B. the nucleus of a mouse cell repairs itself when damaged by bacterial infection.
C. a bacterial cell is transformed into a spore during unsuitable environmental conditions.
D. DNA from an infected mouse cell changes bacteria from a nonpathogenic to a pathogenic form.
E. genetic material is transferred from one bacterial cell to another.
Answer: E
You might also like to view...
Thick-skinned rhinoceroses and elephants were once classified together as pachyderms. They actually descended from different ancestors that in turn evolved from a thin-skinned common ancestor that was not included in the pachyderms. Pachyderms were therefore, as a taxon,
A. polyphyletic. B. polygenetic. C. paraphyletic. D. a supergroup. E. a kingdom.
In cells with a normally functioning CFTR molecule, this molecule moves chloride ions (with
a negative charge) out of the cell to the covering mucus on the outside. Positively charged sodium ions then follow these chloride ions out of the cell to maintain electrical balance. This increases the total electrolyte concentration in the mucus, resulting in the movement of water out of the cell, and this water helps provide a fluid environment. People that have a defective gene (and thus a nonfunctioning CFTR molecule) produce abnormally thick and sticky mucus that builds up in the ducts and passageways. The buildup of this sticky mucus results in lifethreatening lung infections and serious digestive problems. Many charged particles such as ions cannot pass directly across the plasma membrane. Thus, passive transport of the chloride and sodium ions occurs via what process?
a. facilitated diffusion b. active transport c. bulk transport d. osmosis
As one form of energy is converted into another, there is always some energy lost as
a. chemical energy. b. activation energy. c. heat. d. kinetic energy. e. light.
Which of these is true for most water-soluble
hormones? a. They must be transported by specific carriers in the blood. b. They have no trouble entering their target cells. c. They find and react with surface receptor molecules. d. They never elicit the production of a second messenger. e. They trigger gene transcription.