Night blindness, dry skin, and skin infections are typical symptoms of
A. beriberi.
B. scurvy.
C. rickets.
D. vitamin A deficiency.
D. vitamin A deficiency.
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The only known risk factor for autosomal aneuploidy is _____
1.exposure to radiation 2.genetic predisposition 3.viral infection 4.toxoplasmosis 5.advanced maternal age
In humans, ABO blood types refer to glycoproteins in the membranes of red blood cells. There are three alleles for this autosomal gene: IA, IB, and i
The IA allele codes for the A glycoprotein, The IB allele codes for the B glycoprotein, and the i allele doesn't code for any membrane glycoprotein. IA and IB are codominant, and i is recessive to both IA and IB. People with type A blood have the genotypes IAIA or IAi, people with type B blood are IBIB or IBi, people with type AB blood are IAIB, and people with type O blood are ii. If a woman with type AB blood marries a man with type O blood, which of the following blood types could their children possibly have? A) A and B B) AB and O C) A, B, and O D) A, B, AB, and O
A homeobox gene is one that produces a ________
A) transcription factor that strips methylation from the entire genome B) 60 amino acid DNA binding domain C) repetitive nucleotide sequence such as VNTR D) maternal transcription factors
In sexual reproduction in ciliates the sequence of events is
A. (1) In the pair of conjugating cells, the micronuclei undergo mitosis to produce four diploid micronuclei. All but one of these micronuclei disintegrate. (2) The remaining micronucleus undergoes meiosis to produce two. (3) One micronucleus stays in the parent cell and the other moves to the opposite cell while the macronucleus in each cell disintegrates. (4) The cells separate, each with two nuclei. (5) One haploid micronucleus in each cell forms a new haploid macronucleus and the other divides mitotically to form eight new haploid micronuclei. (6) The two haploid macronuclei fuse to form a diploid one and the eight haploid micronuclei fuse by pairs into four diploid micronuclei. B. (1) In each conjugating cell, the micronucleus undergoes meiosis to produce four haploid micronuclei, of which three disintegrate. (2) The remaining micronucleus undergoes mitosis to produce two. (3) One micronucleus stays in the parent cell and the other moves to the opposite cell while the macronucleus in each cell disintegrates. (4) The cells separate, each with two nuclei, one of its own and one from its conjugant. (5) The two haploid micronuclei in each cell fuse to form a diploid micronucleus. (6) The diploid micronucleus divides mitotically, producing four diploid macronuclei and four micronuclei. C. (1) In each conjugating cell, the macronucleus and micronucleus undergo meiosis. One haploid macronucleus and micronucleus disintegrate in each cell. (2) The remaining nuclei undergo mitosis to produce two macronuclei and two micronuclei. (3) One set of nuclei stays in the parent cell and the other moves to the opposite cell. (4) The cells separate, each with two sets of nuclei, one of its own and one from its conjugant. (5) The two haploid micronuclei in each cell fuse to form a diploid micronucleus, and the two macronuclei fuse to form a diploid macronucleus. (6) The diploid nuclei mitotically, producing four diploid macronuclei and four micronuclei.