Chapter 23

Describe three proteins and identify their functions.Describe three proteins and identify their functions.

Compare the structures of amino acids, dipeptides, polypeptides, and proteins. Which has the largest molecular mass? The smallest?

Evaluate How do the properties of proteins make them such useful catalysts? How do they differ from other catalysts you have studied?

Explain three roles of proteins in cells, and give an example of each role.

Explain the functions of carbohydrates in living things.

Describe the structures of monosaccharides, disaccharides, and polysaccharides. Which has the largest molecular mass? The smallest?

Compare and contrast the structures of starch and cellulose. How do the structural differences affect our ability to digest these two polysaccharides?

Cholesterol Use the library or the Internet to research cholesterol. Write a newspaper article about cholesterol that is written for a teenage audience. Make sure the fol- lowing questions are answered in the article. Where is this molecule used in your body? What is its function? Why is too much dietary cholesterol considered to be bad for you? Is genetics a factor in high cholesterol?

Describe the function of lipids.

Describe the structures of fatty acids, triglycerides, phospholipids, and steroids.

List an important function of each of these types of lipids. a. triglycerides c. waxes b. phospholipids d. steroids

Identify two reactions that fatty acids undergo.

Identify two reactions that fatty acids undergo.

Describe the structure and function of cell membranes.

Write the equation for the complete hydrogenation of the polyunsaturated fatty acid linoleic acid, \(\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{4} \mathrm{CH}=\mathrm{CHCH}_{2} \mathrm{CH}=\mathrm{CH}\left(\mathrm{CH}_{2}\right)_{7} \mathrm{COOH} .\)

Explain the primary function of RNA and DNA.

Identify the specific structural components of both RNA and DNA.

Analyze the structure of nucleic acids to determine what structural feature makes them acidic.

Predict what might happen if the DNA that coded for a protein contained the wrong base sequence.

Predict what might happen if the DNA that coded for a protein contained the wrong base sequence.

Compare and contrast the processes of anabolism and catabolism.

Explain the role of ATP in the metabolism of living organisms.

Compare and contrast the processes of photosynthesis, cellular respiration, and fermentation.

Determine whether each process is anabolic or catabolic. a. photosynthesis b. cellular respiration c. fermentation

Calculate How many moles of ATP would a yeast cell produce if 6 mol of glucose were oxidized completely in the presence of oxygen? How many moles of ATP would the yeast cell produce from 6 mol of glucose if the cell were deprived of oxygen?

What should you call a chain of eight amino acids? A chain of 200 amino acids?

Name the two types of functional groups that react together to form a peptide bond, and name the functional group in the peptide bond itself.

Human Anatomy Name five parts of the body that contain structural proteins.

List four major functions of proteins, and give one example of a protein that carries out each function.

Describe two common shapes found in the three dimensional folding of proteins.

Name the organic functional groups in the side chains of the following amino acids. $$\begin{array}{ll}{\text { a. glutamine }} & {\text { c. glutamic acid }} \\\ {\text { b. serine }} & {\text { d. lysine }}\end{array}$$

Explain how the active site of an enzyme functions.

Name an example of an amino acid that has an aromatic ring in its side chain.

Name two nonpolar and two polar amino acids.

Is the dipeptide lysine-valine the same compound as the dipeptide valine-lysine? Explain.

Enzymes How do enzymes lower the activation energy for a reaction?

Cellular Chemistry Most proteins with a globular shape are oriented so that they have mostly nonpolar amino acids on the inside and polar amino acids located on the outer surface. Does this make sense in terms of the nature of the cellular environment? Explain.

How many different ways can you arrange three different amino acids in a peptide? Four amino acids? Five amino acids?

How many peptide bonds are present in a peptide that has five amino acids?

Proteins The average molecular weight of an amino acid residue in a polypeptide is \(110 .\) What is the approximate molecular weight of the following proteins? a. Insulin \((51\) amino acids \()\) b. Myosin \((1750\) amino acids \()\)

The average molecular mass of an amino acid is 110 \(\mathrm{g} / \mathrm{mol}\) . Calculate the approximate number of amino acids in a protein that has a molecular mass of \(36,500 \mathrm{g} / \mathrm{mol}\) .

Carbohydrates Classify the following carbohydrates as monosaccharides, disaccharides, or polysaccharides. $$\begin{array}{llll}{\text { a. starch }} & {\text { d. ribose }} & {\text { g. fructose }} \\ {\text { b. gucose }} & {\text { e. clululose }} & {\text { h. lactose }} \\ {\text { c. sucrose }} & {\text { f. glycosen }}\end{array}$$

Name two isomers of glucose.

What kind of bond is formed when two monosaccha rides combine to form a disaccharide?

Sugars Give a scientific term for each of the following. a. blood sugar b. fruit sugar c. table sugar d. milk sugar

The hydrolysis of cellulose, glycogen, and starch produces only one monosaccharide. Why is this so? What monosaccharide is produced?

Digestion Disaccharides and polysacharides cannot be broken down in the absence of water. Why do you think this is so? Include an equation in vour answer.

Draw the structure of the open-chain form of fructose. Circle all chiral carbons, and then calculate the number of stereoisomers with the same formula as fructose.

Historical Perspective Carbohydrates are not hydrates of carbon as the name suggests. Explain how this mis- conception occurred.

Compare and contrast the structures of a triglyceride and a phospholipid.