Describe the newest method of DNA fingerprinting, which uses PCR and short tandem repeat sequences (STRs).
What will be an ideal response?
Short tandem repeat (STR) profiling is currently the method of choice in DNA fingerprinting. STRs are a type of repetitive element in DNA. Since the locations of these repetitive sequences are known, restriction enzymes are not used and only the location of the STRs is subjected to PCR. In the past, electrophoresis has been used to determine STR banding patterns. Each person has their own number of repeats at different locations and therefore, their own unique banding pattern. The latest methods actually utilize fluorescent labeling of DNA fragments. A laboratory instrument with a laser excites the fluorescent STRs and a detector records the amount of emission for each DNA fragment in terms of peaks and valleys. The greater the fluorescence, the greater the number of repeats at a location. As previously stated, each person has their own banding pattern in electrophoresis and their own unique printout when using fluorescent labeling and a laser.
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Provide evidence that supports the hypothesis that riboswitches are remnants of the RNA world when catalytic RNAs were the only self-replicating life forms
What will be an ideal response?
Which of the following is likely NOT to be a mechanism for controlling hormone levels in the blood?
A. Alter the rate of synthesis and subsequent release of hormone into the blood. B. Change the rate at which an enzyme produces the hormone. C. Modify the structure of the hormone at its point of production so it no longer binds its receptor. D. Alter the rate at which the hormone is removed from the blood. E. Change the rate at which the hormone is excreted into the urine.
All of the following processes are associated with photosystem I EXCEPT
a. ATP synthesis. b. NADPH synthesis. c. cyclic electron flow. d. accepting electrons flowing from the electron transport chain. e. splitting of water.
The transduction of sound waves into electrical signals takes place
A. within the middle ear as the vibrations are amplified by the malleus, incus and stapes. B. within the tectorial membrane as it is stimulated by the hair cell. C. as the basilar membrane becomes more permeable to sodium ions and depolarizes, initiating an action potential in a sensory neuron. D. as the basilar membrane vibrates at different frequencies in response to the varying volume of sounds. E. within hair cells as they are bent against the tectorial membrane, causing them to depolarize and release neurotransmitter that stimulates sensory neurons.