Unit 1: Chapter 5

Question 1

What are macromolecules?

Answer 1

The below are huge, and thus they are called macromolecules

• carbohydrates,
• proteins
• nucleic acids

Question 2

What is a polymer and what is a monomer?

Answer 2

• Polymer: is a long molecule consisting of many similar or identical building blocks linked by covalent bonds, much as a train consists of a chain of cars.
• Monomers: smaller molecules (from the Greek monos, single) - repeating units that serve as the building blocks of a polymer

Question 3

What is the function of an enzyme?

Answer 3

specialized macromolecules that speed up chemical reactions.

Question 4

Define dehydration reaction

Answer 4

• a reaction in which two molecules are covalently bonded to each other with the loss of a water molecule (Figure 5.2a).
  
  • bond forms between two monomers, each monomer contributes part of the water molecule that is released during the reaction:
    
    • One monomer provides a hydroxyl group (¬OH),
    • the other provides a hydrogen (¬H).
    • This reaction is repeated as monomers are added to the chain one by one, making a polymer (also called polymerization).

Question 5

Describe the process of hydrolysis

Answer 5

• Polymers are disassembled to monomers by hydrolysis
• The bond between monomers is broken by the addition of a water molecule, with a hydrogen from water attaching to one monomer and the hydroxyl group attaching to the other.
• Hydrolysis means water breakage (from the Greek hydro, water, and lysis, break).

Question 6

What are the four main classes of large biological molecules? Which class does not consist of polymers?

Answer 6

The four main classes are proteins, carbohydrates, lipids, and nucleic acids. Lipids are not polymers.

Question 7

What is a carbohydrate?

Answer 7

• are polymers called polysaccharides, composed of many sugar building blocks.
• Carbohydrates include sugars and polymers of sugars. The simplest carbohydrates are the monosaccharides

Question 8

• What is a monosaccharide?
• Provide an example

Answer 8

• generally have molecular formulas that are some multiple of the unit CH₂O.
• Glucose
  • Sugars vary in the location of their carbonyl groups (orange on the ss)

Question 9

• What is a disaccharide?
• Provide an example

Answer 9

• consists of two monosaccharides joined by a glycosidic linkage,
  
  • a covalent bond formed between two monosaccharides by a dehydration reaction (glyco refers to carbohydrate).
• examples: sucrose (most prevalent) and maltose
• Disaccharides must be broken down into monosaccharides to be used for energy by organisms.

Question 10

What are polysaccharides?

Answer 10

• macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages.
• Storage: serve as storage material, hydrolyzed as needed to provide sugar for cells.
  
  • starch - plants
  • glycogen - animals
• Structural - Organisms build strong materials from structural polysaccharides.
  
  • cellulose is a major component of the tough walls that enclose plant cells Like starch, cellulose is a polymer of glucose with 1–4 glycosidic linkages, but the linkages in these two polymers differ.
• The architecture and function of a polysaccharide are determined by its sugar monomers and by the positions of its glycosidic linkages.

Question 11

What is cellulose?

Answer 11

polysaccharide - is a major component of the tough walls that enclose plant

Question 12

What is the difference between starch and cellulose?

Answer 12

The difference is based on the fact that there are actually two slightly different ring structures for glucose

• The differing glycosidic linkages in starch and cellulose give the two molecules distinct three-dimensional shapes.
  
  • Certain starch molecules are largely helical, fitting their function of efficiently storing glucose units.
  • a cellulose molecule is straight. Cellulose is never branched

Question 13

What is a chitin?

Answer 13

structural polysaccharide - the carbohydrate used by arthropods (insects, spiders, crustaceans, and related animals) to build their exoskeletons

Question 14

What are lipids?

Answer 14

• the one class of large biological molecules that does not include true polymers, and they are generally not big enough to be considered macromolecules.
• The compounds called lipids are grouped with each other because they share one important trait: They mix poorly, if at all, with water.
  
  • lipids consist mostly of hydrocarbon regions​

Question 15

What is a fat?

Answer 15

A fat is constructed from two kinds of smaller molecules: glycerol and fatty acids

Question 16

What is Saturdated fat?

Answer 16

• structure of the hydrocarbon chains of the fatty acids.
• If there are no double bonds between carbon atoms composing a chain, then as many hydrogen atoms as possible are bonded to the carbon skeleton.
• Such a structure is said to be saturated with hydrogen

Question 17

What is unsaturated fat?

Answer 17

• An unsaturated fatty acid has one or more double bonds, with one fewer hydrogen atom on each double-bonded carbon.
• Kinks in the fatty acid chain, prevent the molecule from tight packing which creates the “oil” state

Question 18

What is a phospholipid?

Answer 18

similar to a fat molecule but has only two fatty acids attached to glycerol rather than three.

• The two ends of phospholipids
  
  • The hydrocarbon tails are hydrophobic and are excluded from water.
  • phosphate group and its attachments form a hydrophilic head that has an affinity for water.
• When phospholipids are added to water = a double-layered sheet called a “bilayer”

Question 19

What is a protein?

Answer 19

• is a biologically functional molecule made up of one or more polypeptides, each folded and coiled into a specific three-dimensional structure.
• Proteins are all constructed from the same set of 20 amino acids,
• The bond between amino acids is called a peptide bond, so a polymer of amino acids is called a polypeptide.