Question 1

What is a biological macromolecule?

Accepted Answer

A large molecule necessary for life that is built from smaller organic molecules.

Question 2

What is dehydration synthesis?

Accepted Answer

A reaction that links monomer molecules together, releasing a molecule of water for each bond formed. AKA condensation.

Question 3

What is hydrolysis?

Accepted Answer

A reaction that causes breakdown of larger molecules into smaller molecules with the utilization of water.

Question 4

What is a monomer?

Accepted Answer

The smallest unit of larger molecules called polymers.

Question 5

What is a polymer?

Accepted Answer

A chain of monomer residues that is linked by covalent bonds; polymerization is the process of polymer formation from monomers by condensation.

Question 6

What are the major classes of biological macromolecules?

Accepted Answer

Carbohydrates, lipids, proteins, and nucleic acids.

Question 7

How does a dehydration synthesis reaction occur?

Accepted Answer

The hydrogen of one monomer combines with the hydroxyl group of another monomer, releasing a molecule of water, while also sharing electrons and forming covalent bonds.

Question 8

What are some of the polymers formed by the glucose monomer?

Accepted Answer

Starch, glycogen, and cellulose.

Question 9

How does hydrolysis occur?

Accepted Answer

A polymer is broken into two components, where one part gains a hydrogen atom (H+) and the other gains a hydroxyl molecule (OH–).

Question 10

How are dehydration and hydrolysis reactions catalyzed?

Accepted Answer

They are catalyzed by specific enzymes; dehydration reactions involve the formation of new bonds, requiring energy, while hydrolysis reactions break bonds and release energy.

Question 11

What are some enzymes that break down carbohydrates?

Accepted Answer

Amylase, sucrase, lactase, maltase.

Question 12

What are some enzymes that break down proteins?

Accepted Answer

Pepsin, peptidase, and hydrochloric acid.

Question 13

What are some enzymes that break down lipids?

Accepted Answer

Lipases.

Question 14

What is a carbohydrate?

Accepted Answer

A biological macromolecule in which the ratio of carbon to hydrogen and to oxygen is 1:2:1; carbohydrates serve as energy sources and structural support in cells and form the cellular exoskeleton of arthropods.

Question 15

What is cellulose?

Accepted Answer

A polysaccharide that makes up the cell wall of plants; provides structural support to the cell.

Question 16

What is chitin?

Accepted Answer

A type of carbohydrate that forms the outer skeleton of all arthropods that include crustaceans and insects; it also forms the cell walls of fungi.

Question 17

What is a disaccharide?

Accepted Answer

Two sugar monomers that are linked together by a glycosidic bond.

Question 18

What is glycogen?

Accepted Answer

Storage carbohydrate in animals.

Question 19

What is a glycosidic bond?

Accepted Answer

A bond formed by a dehydration reaction between two monosaccharides with the elimination of a water molecule.

Question 20

What is a monosaccharide?

Accepted Answer

A single unit or monomer of carbohydrates.

Question 21

What is a polysaccharide?

Accepted Answer

A long chain of monosaccharides; may be branched or unbranched.

Question 22

How many carbons are usually found in monosaccharides?

Accepted Answer

Usually from three to seven.

Question 23

What are some ways in which monosaccharides are classified?

Accepted Answer

Most monosaccharide names end with the suffix -ose. If the sugar has an aldehyde group (the functional group with the structure R-CHO), it is known as an aldose, and if it has a ketone group (the functional group with the structure RC(=O)R'), it is known as a ketose. Depending on the number of carbons in the sugar, they also may be known as trioses (three carbons), pentoses (five carbons), or hexoses (six carbons).

Question 24

What is the chemical formula for glucose?

Accepted Answer

C6H12O6

Question 25

How is glucose used by humans?

Accepted Answer

In humans, glucose is an important source of energy. During cellular respiration, energy is released from glucose, and that energy is used to help make adenosine triphosphate (ATP).

Question 26

What is the source of glucose?

Accepted Answer

Plants synthesize glucose using carbon dioxide and water, and glucose in turn is used for energy requirements for the plant. Excess glucose is often stored as starch that is catabolized by humans and other animals that feed on plants.

Question 27

What are some structural isomers of glucose?

Accepted Answer

Galactose (part of lactose, or milk sugar) and fructose (found in sucrose, in fruit).

Question 28

How are glucose, galactose and fructose classified?

Accepted Answer

They are isomeric monosaccharides (hexoses). Glucose and galactose are aldoses and fructose is a ketose.

Question 29

Are monosaccharides linear- or ring-shaped?

Accepted Answer

They can exist as a linear chain or as ring-shaped molecules; in aqueous solutions they are usually found in ring form.

Question 30

What are the different arrangements of ring-form glucose?

Accepted Answer

Glucose in a ring form can have two different arrangements of the hydroxyl group (OH) around the anomeric carbon (carbon 1 that becomes asymmetric in the process of ring-formation). If the hydroxyl group is below carbon 1 in the sugar, it is said to be in the alpha ( α ) position, and if it is above the plane, it is said to be in the beta ( β ) position.

Question 31

What are the types of glycosidic bonds?

Accepted Answer

Alpha and beta.

Question 32

What are some common disaccharides?

Accepted Answer

Lactose, maltose, and sucrose. Lactose is a disaccharide consisting of the monomers glucose and galactose. It is found naturally in milk. Maltose, or malt sugar, is a disaccharide formed by a dehydration reaction between two glucose molecules. The most common disaccharide is sucrose, or table sugar, which is composed of the monomers glucose and fructose.

Question 33

How large are polysaccharides?

Accepted Answer

The molecular weight may be 100,000 daltons or more depending on the number of monomers joined.

Question 34

How is starch produced?

Accepted Answer

It is made up of a mixture of amylose and amylopectin (both polymers of glucose). Plants are able to synthesize glucose, and the excess glucose, beyond the plant's immediate needs, is stored as starch in different plant parts, including roots and seeds.

Question 35

How is starch consumed?

Accepted Answer

The starch in seeds provides food for the embryo as it germinates and can also act as a source of food for humans and animals. The starch that is consumed by humans is broken down by enzymes, such as salivary amylases, into smaller molecules, such as maltose and glucose. The cells can then absorb the glucose.

Question 36

How are starch monomers joined?

Accepted Answer

Starch is made up of glucose monomers that are joined by alpha 1-4 or alpha 1-6 glycosidic bonds, where the numbers refer to the carbon number of the two residues that have joined to form the bond.

Question 37

How are amylose and amylopectin joined?

Accepted Answer

Amylose is starch formed by unbranched chains of glucose monomers (only alpha 1-4 linkages), whereas amylopectin is a branched polysaccharide (a 1-6 linkages at the branch points).

Question 38

How is glycogen stored and used in animals?

Accepted Answer

Glycogen is highly branched and usually stored in liver and muscle cells. When blood glucose levels decrease, glycogen is broken down to release glucose in a process known as glycogenolysis.

Question 39

What is the most abundant natural biopolymer?

Accepted Answer

Cellulose

Question 40

How are cellulose monomers joined?

Accepted Answer

Cellulose is made up of glucose monomers that are linked by beta 1-4 glycosidic bonds.

Question 41

Why does cellulose have high tensile strength?

Accepted Answer

Every other glucose monomer is flipped over, and the monomers are packed tightly as extended long chains. This gives cellulose its rigidity and high tensile strength, which is important to plant cells.

Question 42

How is cellulose digested?

Accepted Answer

The beta 1-4 linkages cannot be broken down by human digestive enzymes, however herbivores such as cows, koalas, buffalos, and horses are able, with the help of specialized flora in their stomach, to digest plant material that is rich in cellulose. In these animals, certain species of bacteria and protists reside in the rumen (part of the digestive system of herbivores) and secrete the enzyme cellulase. The appendix of grazing animals also contains bacteria that digest cellulose. Cellulases can break down cellulose into glucose monomers that can be used as an energy source by the animal. Termites are also able to break down cellulose because of the presence of other organisms in their bodies that secrete cellulases.

Question 43

What is chitin made of?

Accepted Answer

Repeating units of N-acetyl- β -d-glucosamine, a modified sugar.

Question 44

Where do dietitians work?

Accepted Answer

Registered dietitians help plan nutrition programs for individuals in various settings. They often work with patients in health care facilities, designing nutrition plans to treat and prevent diseases. For example, dietitians may teach a patient with diabetes how to manage blood sugar levels by eating the correct types and amounts of carbohydrates. Dietitians may also work in nursing homes, schools, and private practices.

Question 45

How can you become a dietitian?

Accepted Answer

You need to earn at least a bachelor's degree in dietetics, nutrition, food technology, or a related field. In addition, registered dietitians must complete a supervised internship program and pass a national exam. Those who pursue careers in dietetics take courses in nutrition, chemistry, biochemistry, biology, microbiology, and human physiology. Dietitians must become experts in the chemistry and physiology (biological functions) of food (proteins, carbohydrates, and fats).

Question 46

How many calories are provided by carbohydrates versus fats?

Accepted Answer

Carbohydrate provides 4.3 Kcal/g compared to 9 Kcal/g in fats.

Question 47

What is the role of fiber in diet?

Accepted Answer

Fiber is the insoluble part of carbohydrates and promotes regular bowel movement by adding bulk and regulates the rate of consumption of blood glucose. It also helps to remove excess cholesterol from the body: fiber binds to the cholesterol in the small intestine, then attaches to the cholesterol and prevents the cholesterol particles from entering the bloodstream, and then the cholesterol exits the body via feces. Fiber-rich diets also have a protective role in reducing the occurrence of colon cancer.

Question 48

Why should carbohydrates not be eliminated from diet?

Accepted Answer

Meals containing whole grains and vegetables gives a feeling of fullness. Glucose is broken down to produce ATP, which provides energy. A better way to lose weight is a low-calorie diet that is rich in whole grains, fruits, vegetables, and lean meat, together with exercise and water consumption.

Question 49

What is starch?

Accepted Answer

Storage carbohydrate in plants.

Question 50

What is a lipid?

Accepted Answer

A macromolecule that is nonpolar and insoluble in water.

Question 51

What is an omega fat?

Accepted Answer

A type of polyunsaturated fat that is required by the body; the numbering of the carbon omega starts from the methyl end or the end that is farthest from the carboxylic end.

Question 52

What is a phospholipid?

Accepted Answer

A major constituent of the membranes; composed of two fatty acids and a phosphate-containing group attached to a glycerol backbone.

Question 53

What is a saturated fatty acid?

Accepted Answer

A long-chain of hydrocarbon with single covalent bonds in the carbon chain; the number of hydrogen atoms attached to the carbon skeleton is maximized.

Question 54

What is a steroid?

Accepted Answer

A type of lipid composed of four fused hydrocarbon rings forming a planar structure.

Question 55

What is a trans fat?

Accepted Answer

A fat formed artificially by hydrogenating oils, leading to a different arrangement of double bond(s) than those found in naturally occurring lipids.

Question 56

What is a triglyceride / triacylglycerol?

Accepted Answer

A fat molecule; consists of three fatty acids linked to a glycerol molecule.

Question 57

What is an unsaturated fatty acid?

Accepted Answer

A long-chain hydrocarbon that has one or more double bonds in the hydrocarbon chain.

Question 58

What is a wax?

Accepted Answer

A lipid made of a long-chain fatty acid that is esterified to a long-chain alcohol; serves as a protective coating on some feathers, aquatic mammal fur, and leaves.

Question 59

What are some uses of lipids?

Accepted Answer

Cells store energy for long-term use in the form of fats. Lipids also provide insulation from the environment for plants and animals. They help to keep aquatic birds and mammals dry when forming a protective layer over fur or feathers because of their water-repellant hydrophobic nature. They are also the building blocks of many hormones and are an important constituent of cellular membranes.

Question 60

What are the different types of lipids?

Accepted Answer

Fats, oils, waxes, phospholipids, and steroids.

Question 61

What are triglycerides made of?

Accepted Answer

Glycerol and fatty acids. The fatty acids are attached to each of the three carbons of the glycerol molecule with an ester bond through an oxygen atom. The three fatty acids in the triacylglycerol may be similar or dissimilar.

Question 62

What is glycerol?

Accepted Answer

Glycerol is an organic compound (alcohol) with three carbons, five hydrogens, and three hydroxyl (OH) groups.

Question 63

What is a fatty acid?

Accepted Answer

Fatty acids have a long chain of hydrocarbons to which a carboxyl group is attached, hence the name “fatty acid”. The number of carbons in the fatty acid may range from 4 to 36; most common are those containing 12 to 18 carbons.

Question 64

What happens during the ester bond formation of triglycerides?

Accepted Answer

Three water molecules are released.

3: Biological Macromolecules Flashcards

Synthesis of Biological Macromolecules, Carbohydrates, Lipids, Proteins, Nucleic Acids

Brainscape's Knowledge GenomeTM

3: Biological Macromolecules Flashcards

Synthesis of Biological Macromolecules, Carbohydrates, Lipids, Proteins, Nucleic Acids

Brainscape's Knowledge Genome^TM