Biology 112 Chapters 5 and 41

ribbon

Which of the three different representations of protein structure is most useful for studying the interior shapes formed by the folds of the protein?

4. RNA

Which of these is NOT a lipid? 1. steroids 2. cholesterol 3. wax 4. RNA 5. phospholipid

liver ... gall bladder

Bile is produced by the _____ and stored by the _____ until it is secreted into the small intestine.

Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart

Which of the following best compares dehydration reactions and hydrolysis?

3. has alpha 1-6 glyosidic bonds

Which of the following best describes glycogen? 1. a storage polysaccharide found in plants 2. a fibrous protein that helps in maintaining cellular structure 3. has alpha 1-6 glyosidic bonds. 4. is formed by the hydrolysis of glucose molecules.

pancreas ... pancreatic enzymes

Cholecystokinin (CCK) stimulates the _____ to secrete _____.

small intestine

In which organ does almost all enzymatic digestion of food occur?

lipid

Which molecule is not a carbohydrate?

deoxyribose, phosphate group, thymine

Identify three possible components of a DNA nucleotide.

75

If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain?

3'-TAAACG-5'

If a strand of DNA has the nitrogen base sequence 5'-ATTTGC-3', what will be the sequence of the matching strand?

water molecules form H-bonds with each other and exclude fat

In a bottle of salad dressing, the vinegar separates from the oil because ________.

could not make many necessary proteins

Lysine is an essential amino acid for animals. An animal that lacked lysine in its diet ________.

3. carbohydrate

Which of the following categories includes all others in the list? 1. starch 2. polysaccharide 3. carbohydrate 4. disaccharide

cellulose: structural component of plant cell walls

Which of the following complex carbohydrates is listed with its correct function?

2. An individual's insulin receptors are defective. 3. An individual has an autoimmune disorder that destroys the beta cells of the pancreas.

Which of the following hypothetical situations might result in a blood sugar level that is too high? Select all that apply. 1. A diabetic accidentally injects too much insulin. 2. An individual's insulin receptors are defective. 3. An individual has an autoimmune disorder that destroys the beta cells of the pancreas.

Monosaccharides can be classified according to the spatial arrangement of their atoms.

Which of the following statements about monosaccharide structure is true?

3. The polar heads interact with water, the nonpolar tails do not

Which of the following statements describes the interaction of water molecules with phospholipids? 1. Phospholipids dissolve in water. 2. The polar heads avoid water; the nonpolar tails attract water (because water is polar and opposites attract). 3. The polar heads interact with water; the nonpolar tails do not. 4. Phospholipids do not interact with water because water is polar and lipids are nonpolar.

2. The primary structure of a protein is the order of amino acids in a polypeptide, as coded for in the DNA of a gene

Which of the following statements is an accurate description of proteins? 1. The 20 amino acids found in proteins differ in the composition of their R groups, which may be either polar or charged. 2. The primary structure of a protein is the order of amino acids in a polypeptide, as coded for in the DNA of a gene. 3. Secondary structures, which include the alpha helix or beta pleated sheet, are held together by interactions between R groups. 4. Tertiary structure is the overall shape of a polypeptide, which may be stabilized by hydrophobic interactions, hydrogen bonds, ionic bonds, and peptide bonds. 5. Quaternary structure is only found in proteins that have four identical polypeptide subunits.

2. a disaccharide

Which of the following terms does not describe a molecule of glucose? 1. a hexose 2. a disaccharide 3. an aldose 4. an isomer of fructose

backbone

Which of the three different representations of protein structure is most useful for observing the path of the protein chain from one amino acid to the next?

spacefill

Which of the three different representations of protein structure is most useful for studying the exterior of the protein?

cellulose

Which of these is a polysaccharide?

3. olive oil

Which of these is rich in unsaturated fats? 1. butter 2. lard 3. olive oil 4. beef fat 5. a fat that is solid at room temperature

peptidoglycan

Which polysaccharide contains a modified monosaccharide?

absorption

Which process does the large surface area in the intestine make more efficient?

excretion

Which process is not required for an animal to obtain energy from food?

4. break peptide bonds of proteins in the stomach

Which statement best describes what secretions of the parietal cells do upon activation by stomach acidity? 1. initiate the chemical digestion of lipids in the stomach 2. slow the mechanical digestion of lipids in the stomach 3. delay digestion until the food arrives in the small intestine 4. break peptide bonds of proteins in the stomach

2. These proteolytic enzymes, in active form, would digest the very tissues that synthesize them

Which statement best describes why cells of the digestive system secrete proteolytic enzymes, such as pepsin, in their inactive forms? 1. Inactive pepsin and trypsin are more easily transported across the cell membrane 2. These proteolytic enzymes, in active form, would digest the very tissues that synthesize them. 3. The stomach is too acidic to maintain these enzymes in their active form. 4. By secreting inactive enzymes, the catalytic activity of the enzymes is maintained for a longer time.

2. salivary glands

Which structure is not part of the alimentary canal? 1. Esophagus. 2. Salivary glands. 3. Mouth. 4. Stomach.

these proteolytic enzymes, in active form, would digest the very tissues that synthesize them

Why do the cells of the digestive system secrete proteolytic enzymes, such as pepsin, in their inactive forms?

protein

The digestion of ________ begins in the stomach.

a polysaccharide found in animals

Glycogen is ______?

hydrogen bonds

The secondary structure of a protein results from ______.

1. disaccharide 2. carbohydrate 3. monosaccharide 4. polysaccharide

1. Lactose, the sugar in milk, is a ________, because it can be split into two monosaccharides. 2. A simple sugar is composed of equal parts carbon and water, which gave rise to the general name of any sugar as a ________ . 3. A ________ cannot be hydrolyzed any further. 4. A carbohydrate that yields many monosaccharides when hydrolyzed is a ________.

1. folic acid 2. vitamin A 3. vitamin C 4. water-soluble vitamins 5. fat-soluble vitamins

1. _______ is a vitamin that is used in reactions that transfer single-carbon units. The vitamin also helps reduce the risk of birth defects such as spina bifida and cleft lip. Women of child-bearing age should consume the recommended amount of this vitamin. 2. _______ is absorbed from some foods like carrots in the form of carotene. The vitamin accumulates in the rods and cones of the eyes and plays a role in vision. 3. ________ is involved in the formation of hydroxyproline and hydroxylysine, which are important amino acids and part of the collagen that forms the connective tissues. Lack of this vitamin causes scurvy, which can be prevented with citrus and other fruits. 4. The ________ act as coenzymes in the body. They do not stay bonded to only one enzyme, but are used over and over again by different enzymes. 5. The _________ are not involved as coenzymes. But they are still essential in our diet, and they are involved in important processes such as vision, bone formation, protection from oxidation, and blood clotting.

water molecules are produced as a polymer formed from monomers

A dehydration reaction (or condensation reaction) is the process in which __________.

as a component of animal cell membranes

A function of cholesterol that does not harm health is its role _____.

on the inside of the folded chain, away from water molecules

A hydrophobic amino acid R group (side group) would be found where in a properly folded protein?

phosphate group, a nitrogen-containing base, and a five-carbon sugar

A nucleotide is composed of a(n) _____.

breaking down organic molecules

Animals obtain the energy they need for growth by ______.

enzymatic hydrolysis

Because the foods eaten by animals are often composed largely of macromolecules, animals need to have mechanisms for _____.

3. Proteins that are consumed in the diet are absorbed as individual amino acids following digestion.

Choose the correct statement from the list below. 1. The stomach has a high pH which allows for the activation of digestive enzymes. 2. Protein digestion begins in the small intestine with the activation of trypsinogen to trypsin 3. Proteins that are consumed in the diet are absorbed as individual amino acids following digestion. 4. Mechanical digestion of proteins is more important than chemical digestion.

2

How many fatty acids are in a phospholipid?

21

How many molecules of water are required for the hydrolyzation of a polymer that is 22 monomer-long cellulose molecule?

Essential nutrients must be obtained from diet.

How must essential nutrients be obtained?

4 only

Examine the digestive system structures in the figure. Most of the digestion of fats occurs in structure(s) ________.

4

Examine the digestive system structures in the figure. The highest rate of nutrient absorption occurs at location ________.

both use water molecules when breaking bonds (hydrolysis)

Fat digestion yields fatty acids and glycerol, whereas protein digestion yields amino acids. Which of the following statements is true regarding these processes?

use water molecules when breaking bonds (hydrolysis)

Fat digestion yields fatty acids and glycerol, whereas protein digestion yields amino acids; both digestive processes _____.

1. Secondary 2. Quaternary 3. Primary 4. Tertiary

Fill in the blanks with "primary, secondary, tertiary, or quaternary" 1. ________ structure describes the alpha-helices and beta-sheets that are formed by hydrogen bonding between backbone atoms located near each other in the polypeptide chain. 2. ________ structure is the result of two or more protein subunits assembling to form a larger, biologically active protein complex. 3. ________ structure is the sequence of amino acids in a protein. 4. _______ structure is achieved when a protein folds into a compact, three-dimensional shape stabilized by interactions between side-chain R groups of amino acids.

Secretin increases the flow of bicarbonate ions from the pancreas into the small intestine to neutralize the stomach acid.

Food being digested in the stomach is in a highly acidic environment. The pH of the small intestine is higher than that of the stomach. Why is this?

mouth

For ingested foods, the first opportunity for enzymatic digestion occurs in the _____.

Insulin causes some cells to take up glucose, whereas glucagon causes some cells to secrete glucose

How do glucagon and insulin differ?

HCl

Pepsinogen is converted to its active form in the stomach by ________.

4 molecules of glucose and 3 molecules of water

The molecular formula of a carbohydrate molecule is C24H42O21. The maximum number of glucose and water molecules that will be consumed by complete hydrolysis of the carbohydrate is ________.

amino acids

Proteins are polymers of _____.

other amino acids

Proteins consist of amino acids linked to ______.

pancreas ... bicarbonate

Secretin stimulates the _____ to secrete _____.

peptide

What type of bond joins the monomers in a protein's primary structure?

Carbohydrate digestion begins in the mouth with salivary amylase

Where does carbohydrate digestion begin?

peptide bonds

Tertiary structure is NOT directly dependent on ______.

secretin

The acidity of the stomach contents triggers the small intestine to secrete a hormone known as _____.

none of them dissolves in water

The characteristic that all lipids have in common is __________.

the position of the carbonyl group

The difference between an aldose sugar and a ketose sugar is ________.

glycogen, starch, and amylopectin

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the α form. Which of the following could amylase break down?

calcium, sodium, potassium, and other minerals

The essential nutrients for proper human nutrition include ______.

regurgitation of acidic stomach contents into the esophagus, commonly called "heartburn"

The lower esophageal sphincter surrounds the upper opening into the stomach. If this sphincter failed to properly constrict, there might be a problem with _____.

C60H102O51

The molecular formula for glucose is C6H12O6C6H12O6. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?

cholecystokinin, or CCK

The presence of fatty acids and amino acids in the chyme from the stomach triggers the small intestine to secrete a hormone known as _____.

absorption

The process by which digested dietary substances cross cell membranes to be used by the body is known as ________.

ingestion

The process of obtaining food is known as ________ and requires specialized feeding mechanisms.

primary level

The structural level of a protein least affected by a disruption in hydrogen bonding is the

Free fatty acid absorption occurs in the small intestine

Where does free fatty acid absorption occur?

Amylose

Which complex carbohydrate contains only a-1,4-glycosidic linkages?

A fat molecule is less soluble in water because it has three non-polar fatty acids and no polar or charged head like a phospholipid has.

Which molecule is less soluble in water--a fat or a phospholipid? Why?

hydrogen bonds

The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases.

saturated fat

This figure is an example of a(n) _____.

True

True or false? Peptidoglycan is a polysaccharide found only in bacteria.

The new amino acid would not form the same interactions with hydrophobic R groups, and the protein's shape would likely be affected

What could happen if a mutation in a gene caused a hydrophobic amino acid in a polypeptide to be replaced by a hydrophilic amino acid?

has both hydrophilic and hydrophobic properties and is found in plasma membranes

What does this molecule represent?

saturated fatty acid

What does this molecule represent?

negative charge to interact with water place to attach another small charged molecule

What functional feature(s) does the phosphate group contribute to the structure of a phospholipid?

hydrophilic and hydrophobic interactions with water

What holds phospholipids together in a bilayer formation?

Vitamins are organic molecules, but minerals are inorganic molecules

What is a difference between vitamins and minerals?

pharynx, esophagus, stomach, small intestine, large intestine

What is the correct anatomical sequence that presents the order in which food in the digestive system passes through?

polysaccharide digestion

What is the function of the small intestine?

They are glycoproteins that make food slippery enough to slide easily through the esophagus

What is the importance of the mucus that are released by salivary glands?

starch and cellulose differ in the glycosidic linkages between their glucose monomers

What structural difference accounts for the functional differences between starch and cellulose?

Cysteine residues are involved in disulfide bridges that help form tertiary structures

You have just sequenced a new protein isolated from mice and observe that sulfur-containing cysteine residues occur at regular intervals. "This finding is most consistent with which of the following claims about the protein?

Cellulose

_____ is the most abundant organic compound on Earth.

maltose + water ... dehydration synthesis

glucose + glucose —> _____ by _____.