Although the expression of most genes is tightly regulated, some genes are expressed at roughly constant rates. Which of the following genes would you predict to be constitutively (constantly) expressed?
A) genes involved in the biosynthesis of the amino acid tryptophan
B) genes involved in the degradation of tryptophan
C) genes involved in the degradation of arabinose, a sugar
D) genes that code for regulatory proteins
Answer: D
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Observe the photomicrograph accompanying this question. This thin section of a potato tuber has been stained with Lugol’s iodine solution. When you eat french fries, the potato material is broken down in your small intestine into what kind of small subunits?
What will be an ideal response?
Why is it useful to know the structure of a protein when trying to understand a protein's function?
a. Scientists still don't know exactly what features of a protein's structure determine how a protein works. By gathering information about many different protein structures and correlating them to their known functions, we can try to figure out this relationship. b. Since all proteins have enzymatic activity, we hope to learn what features of a protein make an enzyme a catalyst. c. Since x-rays are used on protein crystals to determine the structure, this research can help us understand the ways in which x-rays can be damaging to the proteins of living cells. d. The enzymatic activity of a protein cannot be measured unless we also have the structure of that enzyme. e. We need to know which amino acids are essential for a cell to function. If we know the structure of an enzyme, we can determine which amino acids are present and how they work in the cell.
____ are long-chain fatty acids attached to
long-chain alcohols. a. Triglycerides b. Phospholipids c. Sterols d. Waxes e. Most neutral fats
What type of test is a CEA test?
A. self-examination B. a type of cervical cancer test C. a type of prostate cancer test D. a tumor marker test E. a genetic test