According to the fluid mosaic model of cell membranes, which of the following is a TRUE statement about membrane phospholipids?
A) They frequently flip-flop from one side of the membrane to the other.
B) They form a viscous fluid through which proteins shift and flow.
C) They have hydrophilic tails in the interior of the membrane.
D) They occur in an uninterrupted bilayer, with membrane proteins strictly anchored to the surface of the membrane.
E) They are free to depart from the membrane and are dissolved in the surrounding solution.
B
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____ are meristems in gymnosperms and angiosperms that are often dormant. Upon activation, these structures will go on to form lateral branches
Fill in the blank with the appropriate word.
Genetic studies of an animal show that eye color is controlled by an autosomal gene with the dominant
allele (R) for red eye color and the recessive allele (r) for yellow eye color. A second autosomal gene has the dominant allele (T) leading to paws with thumbs while the recessive allele (t) codes for paws without thumbs. The genetic cross RRTT ? rrtt creates offspring with genotype RrTt. One of those dihybrids is mated in a testcross (RrTt ? rrtt). If the two genes are completely linked (no recombination occurs between them), then the testcross should produce offspring with the phenotype ratio
a. 3 red-eyed with thumbs: 1 yellow-eyed without thumbs. b. 1 red-eyed with thumbs: 1 yellow-eyed with thumbs: 1 red-eyed without thumbs: 1 yellow-eyed without thumbs. c. 1 red-eyed with thumbs: 1 yellow-eyed without thumbs. d. 9 red-eyed with thumbs: 3 yellow-eyed with thumbs: 3 red-eyed without thumbs: 1 yellow-eyed without thumbs. e. 1 yellow-eyed with thumbs: 1 red-eyed without thumbs.
Which was an early tetrapod innovation?
a. limbs evolved from dorsal fins b. cartilaginous pectoral girdle c. four chambered heart d. stereoscopic vision e. inner ear changes to detect airborne sounds
These structures serve as gates that regulate blood flow from arterioles into capillaries
A) vasoconstrictors B) capillary beds C) precapillary sphincters D) capillary pores E) interstitial gates