Chapter Questions
Do plant cells have a plasma membrane?
What are the four major categories of biomolecules
Are all carbohydrates digestible by humans?
How does the chemical structure of the monosaccharide glucose differ from that of the monosaccharide fructose?
Why do plants produce starch?
Which monosaccharide do starches and cellulose have in common?
What is the most abundant organic compound on Earth?
What are the structural components of a triglyceride?
What makes a saturated fat saturated?
What do all steroids have in common?
What are the building blocks of a protein molecule?
How do various amino acids differ from one another?
What do a peptide, polypeptide, and protein all have in common?
What does disulfide cross-linking do for a protein?
What is the role of enzymes in the body?
What holds a substrate to its receptor site?
What is the difference between a nucleic acid and a nucleotide?
Where in the cell are ribonucleic acids found?
Where in the cell are deoxyribonucleic acids found?
Which four nitrogenous bases are found in DNA? In RNA?
Are codons found in DNA or in RNA?
On what form of RNA are anticodons found?
What are two classes of vitamins?
Why is it often more healthful to cat vegetables that have been steamed rather than boiled?
What is the general outcome of catabolism?
What is the general outcome of anabolism?
Which type of biomolecule does the food pyramid recommend we eat the most of?
Are all dietary fibers made of cellulose?
Which type of lipoproteins has a greater association with the formation of plaque on artery wall: LDLs or HDIs?
Why doesn't the human body synthesize the essential amino acids?
In Does a carbohydrate contain water?
What is another biological use for carbohydrates besides energy?
In what ways are cellulose and starch similar to each other? In what ways are they different from cach other?
Why does starch begin to taste sweet after it has been in your mouth for a fcw minutes?
How does amylose differ from amylopectin?
Why are lipids insoluble in water?
Why is it important to have cholesterol in your body?
Could a food product containing glycerol and fatty acids but no triglycerides be advertised as being fatfree? If so, how might such advertising be misleading?
In Silk is more waterproof than cotton. Why?
You are a beautician about to apply a reducing agent to a customer with fine hair who wants to have his hair curly. Should the reducing agent be regular strength, concentrated, or dilured?
Why is a permanent wave not really permanent?
Why can't your body produce protcins from carbohydrates and fats alone?
When an unknown peptide containing five amino acids is treated with an enzyme that hydrolyzes only the serine-leucine peptide bond, the fragments Leu-Gys, Ser, Leu-Ser are formed. What was the original amino acid sequence in the peptide?
Identify the molecular attractions occurring in this large protein at the locations $a, b$, and $c$ Distinguish among the primary, secondary, and tertiary structures of this protein.
Why do changes in $\mathrm{pH}$ interfere with the function of proteins? For your answer, consider the acidbase character of many amino acid side chains.
What are the two most common sccondary structures in a protein? 'The two most common tertiary structures?
Name the four structural levels possible in a protein, and describe the details of each.
What is the difference between transcription and translation?
Which amino acid is coded for by the nitrogenous-base sequence $\mathrm{AGG}$ ?
What is a restriction enzyme, and what does it do?
What is a sticky end in a DNA fragment, and how are sticky ends useful in the formation of recombinant DNA?
List codon, gene, nucleic acid, and nucleotide in order of increasing size.
A common source of DNA damage is the spontaneous loss of the amine group on cytosine and the formation of an amide. This occurs at a rate of about 100 times a day. Fortunately, the body produces enzymes able to detect and repair such degraded cytosines. Given this information, suggest why DNA differs from RNA in possessing the nuclectide thymine rather than uracil.
Which amino acid does the DNA sequence ATG code for?
Why is the number of adenines in a DNA molecule always the same as the number of thymines?
What polypeptide is coded for by the mRNA sequence AUGGACCCAGCGUGAUGUA?
What polypeptide would be coded for by the $\mathrm{mRNA}$ sequence in exercise 56 if the second $\mathrm{G}$ from the left were somehow deleted? What problems might this change cause in a gene?
Why does mRNA not remain associated with DNA after being generated through transcription?
How many symmetrical sequences can you find in the following DNA segment?
Both water-soluble and water-insoluble vitamins can be toxic in large quantities. Our bodies are much morc tolerant of the water-soluble ones, however. Why?
The dietary minerals must be in ionic form in order for the body to make use of them. Why?
A friend of yours loads up on vitamin C once a week instead of spacing ir out over time. She argues the convenience of not having to take pills every day. Whar advice do you have for her?
Which statement is more accurate?a. Vitamins are needed by the body to avoid vitamindeficiency diseases, such as scurvy.b. Vitamins are needed by the body so that many of its catabolic and anabolic reactions can proceed efficiently.
In Suggest why the glycemic index for sucrose is only about 64 percent that of glucose.
Suggest why starch takes longer to break down to glucose in the intestine than does sucrose.
Is it possible to eat a food low on the glycemic index and still cxperience a significant increase in bluod glucose?
Mammals cannot produce polyunsaturated fatty acids. How is it then that the lard obrained from beef fat contains up to 10 percent polyunsaturated farty acids?
Peanut butter has more protein per gram than a hard-boiled egg, and yet the egg represents a hetter source of protein. Why?
The human body stores excess glucose as glycogen and excess fat as fatty tissue that can accumulate beneath the skin. How does the body store any excess amino acids?
Cold cereal is of ten fortified with all sorts of vitamins and minerals but is deficient in the amino acid lysine. How might this deficiency be compensated for in a breakfast meal?