Bacteria, fungi, and plants cells use a gradient of _______ ions across their plasma membranes to drive transport of other molecules into the cells.
a. Na+
b. K+
c. H+
d. Ca2+
Ans: d. Ca2+
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Which of the following is not a property of
living things? a. They can change over generations. b. They use DNA as the genetic material. c. They change over their lifetime. d. They engage in processes to maintain homeostasis. e. All of these are true
Which of the following statements about the human genome is INCORRECT?
A) There are approximately 3.1 billion bp in the human genome. B) Human share a majority of genes with other species. C) Less than 2 percent of the genome codes for proteins. D) The human genome contains approximately 100,000 genes. E) The functions of most human genes are still unknown.
Although they are smaller than K+, Na+ ions fail to pass through K+ channels because Na+
A) is repulsed by positively charged amino acids at the mouth of the channel. B) is too small to interact with oxygen atoms in amino acids on all sides of the channel and therefore does not completely lose its waters of hydration. C) is always transported complexes to Cl?. D) is always transported in a complex with two other Na+ ions. E) is attracted by other Na+ ions, which are at higher concentration outside than inside the cell.
Sexual reproduction in animals starts with diploid ________ cells that form haploid __________
Fill in the blank(s) with the appropriate word(s).