The primitive template that was thought to be
used for forming chains that resemble proteins
or nucleic acids was
a. meteorites that landed in the oceans.
b. clay particles in tidal flats.
c. sulfur that precipitated out of hydrothermal
vents.
d. rusty rocks.
e. magma spewed from early volcanic
activity
B
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Since the hepatic portal vein empties into the liver, it is able to control the amount of _________ in the blood.
A. alcohol and drugs B. toxins, pesticides, and carcinogens C. glucose D. glucose, alcohol, and drugs E. glucose, alcohol, drugs, toxins, pesticides, and carcinogens
In an experiment, DNA from the linear form of the bacteriophage Lambda was cut into fragments using the restriction enzyme Hind III. Restriction enzymes are isolated from bacteria and cut DNA in specific locations
Hind III cuts the Lambda DNA between the adenine nucleotides on the complimentary strands in a specific sequence, as indicated in the diagram, producing eight different size fragments. These fragments are then separated with an electrical current based on size after the DNA fragments are placed in a porous gel, a process called gel electrophoresis. cut site ? 5' A A G C T T 3' 3' T T C G A A 5' ? cut site Select an observation that best describes a correct aspect of the two processes of restriction digest and gel electrophoresis: A) When separated on a gel, the pattern of DNA bands will be characteristic of those cut with Hind III, different restriction enzymes will not produce these same fragments. B) The sequence AAGCTT is found eight times in the Lambda genome and the restriction enzyme Hind III finds each location. C) If an electrical current is not used, eight separate DNA bands would be visible, but they would not be separated as much as when an electrical current is used. D) Only the restriction enzyme Hind III can be used to cut Lambda DNA since restriction enzymes are specific to the type of DNA they can cut.
Answer the following statements true (T) or false (F)
1. Dehydration synthesis reactions always involve the removal of a molecule of water. 2. The biosynthesis of polysaccharides, polypeptides, and nucleic acids are examples of catabolic reactions. 3. Oxidation–reduction reactions are paired reactions that involve the transfer of electrons. 4. Breaking a disaccharide down into its two monosaccharide components is an example of a hydrolysis reaction. 5. Anabolic reactions are a cell's major source of energy.
If the K+ channels of an excitable plasma membrane were blocked by the action of a drug, which process(es) would be
disrupted?
a. repolarization b. depolarization c. hyperpolarization d. repolarization and depolarization e. repolarization and hyperpolarization