Chapter 23

Describe three proteins and identify their functions.

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 polysacharides?

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. \(\begin{array}{ll}{\text { a. triglycerides }} & {\text { c. waxes }} \\\ {\text { b. phospholipids }} & {\text { d. steroids }}\end{array}\)

Identify two reactions that fatty acids undergo.

Describe the structure and function of cell membranes.

Compare and contrast the structures of a steroid, a phospholipid, and a wax.

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

Explain the primary function of RNA and DNA.

Identify the specific structural components of both RNA and DNA.

Relate the function of DNA to its structure.

Relate the function of RNA to its structure.

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.

Explain why metabolism is important to living cells.

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

Evaluate Why is it necessary to use sealed casks when making wine?

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.

Using the four symbols shown to represent four different amino acids, draw structures four possible peptides for a four-member chain that can be made by linking them together in different orders \(\begin{array}{ll}{\text { Amino acid } 1 : } & {\text { Amino acid } 3 :} \\\ {\text { Amino acid } 2 : } & {\text { Amino acid } 4 :}\end{array}\)

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 non polar 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 non polar 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 g/mol. Calculate the approximate number of amino acids in a protein that has a molecular mass of 36,500 g/mol.

Carbohydrates Classify the following carbohydrates as monosaccharides, disaccharides, or polysaccharides. \(\begin{array}{lll}{\text { a. starch }} & {\text { d. ribose }} & {\text { g. fructose }} \\ {\text { b. glucose }} & {\text { e. cellulose }} & {\text { h. lactose }} \\ {\text { c. sucrose }} & {\text { f. glycogen }}\end{array}\)

Name two isomers of glucose.

What kind of bond is formed when two monosaccharides 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

Chemistry in Plants Compare and contrast the functions of starch and cellulose in plants. Explain why their molecular structures are important to their functions.

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

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