Midterm 4 - Carbohydrates - Google Docs

What three elements are the primary building blocks of all carbohydrates?

Carbon, Hydrogen, and Oxygen ($C, H, O$)

What is the standard ratio of Hydrogen to Oxygen found in most simple carbohydrates?

$$2:1$$

What is the term for a single, fundamental sugar unit?

Monosaccharide

What is the specific molecular formula for the hexose sugar glucose?

$$C_6H_{12}O_6$$

How are isomers like glucose and fructose defined in terms of their composition?

They share the same molecular formula ($C_6H_{12}O_6$) but have different structural arrangements

What is the structural difference between an aldose and a ketose?

An aldose has its carbonyl group at the end of the carbon skeleton, whereas a ketose has it located within the skeleton

What type of covalent bond connects two monosaccharides to form a larger carbohydrate?

Glycosidic linkage

Identify the chemical reaction that links sugar monomers by removing a water molecule.

Dehydration synthesis (or condensation reaction)

Which process is used to break down polysaccharide chains into smaller units by adding water?

Hydrolysis

Which two monosaccharides combine to produce the disaccharide sucrose?

Glucose and fructose

Which two monosaccharides are required to synthesize the disaccharide lactose?

Glucose and galactose

Which disaccharide is formed by the union of two glucose molecules?

Maltose

What is the primary energy storage polysaccharide used by plants?

Starch

Specify the unbranched form of starch that consists of $\alpha-1,4$ glycosidic linkages.

Amylose

What is the term for the branched form of starch that contains both $\alpha-1,4$ and $\alpha-1,6$ glycosidic bonds?

Amylopectin

Which extensively branched polysaccharide serves as the energy storage molecule in animals?

Glycogen

In human physiology, where is glycogen most commonly stored?

The liver and skeletal muscle cells

Which structural polysaccharide is the main component of plant cell walls?

Cellulose

Why is cellulose a highly stable and structural molecule?

It consists of $\beta$-glucose monomers that form straight chains held together by hydrogen bonds

Which structural polysaccharide contains nitrogen and is found in the exoskeletons of arthropods?

Chitin

Why are humans unable to digest the cellulose found in plant matter?

Humans do not possess the enzymes necessary to hydrolyze $\beta$-glycosidic linkages

What is the typical molecular formula for a disaccharide like sucrose or maltose?

$$C_{12}H_{22}O_{11}$$

Provide an example of a five-carbon sugar (pentose).

Ribose or Deoxyribose

What is the major chemical difference between $\alpha$-glucose and $\beta$-glucose?

The orientation of the hydroxyl group ($-OH$) on the first carbon atom of the ring

What are the two primary biological functions of carbohydrates in living organisms?

Providing immediate energy storage and serving as structural support materials