Carbohydrates

• What elements do carbohydrates contain?

  Carbon, hydrogen, and oxygen
• Which molecules are included under the umbrella of carbohydrates?

  Sugars, starches, cellulose, and glycogen
• Into how many groups can carbohydrates be subdivided?

  1. Monosaccharides
  2. Disaccharides
  3. Polysaccharides
• What is the general formula of monosaccharides?

  $C_nH_{2n}O_n$
• How are monosaccharides defined?

  They are simple, single sugars, or monomers.
• What happens when monosaccharides dissolve in water?

  They dissolve easily in water to form sweet solutions.
• What is the formula of glucose?

  $C_6H_{12}O_6$
• Name three common six-carbon sugar (hexose) monosaccharides.

  Glucose, fructose, and galactose
• What are the main roles of glucose?

  Glucose is the main respiratory substrate and building block for both disaccharides and polysaccharides.
• What are the two main forms of glucose?

  • Alpha $(\alpha)$ glucose
  • Beta $(\beta)$ glucose
• Why are both alpha and beta glucose important?

  Both forms of glucose are important in the formation of polysaccharides.
• What are the key structural differences between sugars, starches, cellulose, and glycogen?

  • Sugars: Simple, single sugar units (monosaccharides).
  • Starches: Mixtures of amylose and amylopectin, polymers of glucose.
  • Cellulose: Long, unbranched chains of β-glucose units.
  • Glycogen: Highly branched polymers of α-glucose.
• How can carbohydrates be classified according to their size?

  • Monosaccharides: Simple sugars, single sugar units.
  • Disaccharides: Two monosaccharides linked together.
  • Polysaccharides: Many monosaccharides linked together to form large macromolecules.
• Which sugar is most commonly found in our diet?

  Sucrose
• What is the primary role of sucrose in our diet?

  It serves as a source of energy.
• In which foods is starch found?

  Potato, bread, rice, and cereals
• Why are carbohydrates sometimes referred to as organic molecules?

  Because carbon is the central element in carbohydrates.
• How can you remember the structural difference between alpha and beta glucose?

  α glucose: OH group is pointing away from the oxygen; β glucose: OH group is beside the oxygen.
• Name two other hexose sugars besides glucose.

  Fructose and galactose
• How are fructose and galactose related to glucose?

  They are structural isomers, having the same formula but different structures.
• What is the name of the bond formed between two monosaccharides?

  Glycosidic bond
• How are glycosidic bonds broken?

  Glycosidic bonds can be broken by hydrolysis reactions, using water and enzymes.
• What are the key features of disaccharides?

  • General formula of $C_{12}H_{22}O_{11}$
  • Transport energy or respiratory substrates
  • Formed by linking two monosaccharides through a condensation reaction
  • Contain a glycosidic bond
  • Glycosidic bonds can be broken by hydrolysis
• What type of bond is found in disaccharides?

  Glycosidic bond
• What is the general formula of polysaccharides?

  $C_n(H_2O)_n - H_2O$
• How are polysaccharides formed?

  Many single sugars are joined together by condensation reactions to form large macromolecules.
• What are the main functions of polysaccharides?

  • Energy storage
  • Structural roles in plant cells
• Starch is a mixture of which two polymers?

  Amylose and amylopectin
• What are the two forms of glucose polymers in starch?

  Amylose (unbranched) and amylopectin (branched)
• How is the structure of amylose held together?

  Spirals held by hydrogen bonds (H-bonds)
• What does amylopectin form?

  Amylopectin forms a slightly packed brush-like molecule.
• What is the main component of plant cell walls?

  Cellulose
• How does the compact structure of starch benefit plant cells?

  • Allows many glucose molecules to be stored in a small space.
  • Starch is insoluble, preventing it from affecting the osmotic potential of the cell.
• What function does cellulose serve in plant cells?

  It forms long fibers that provide structural support and extra strength, allowing the cell wall to expand slightly when the cell takes up water by osmosis.
• Where is glycogen found and what is it made up of?

  Glycogen is a storage carbohydrate in animal cells made up of α-glucose.
• How does glycogen compare to amylopectin in animal cells?

  It is very similar to amylopectin but much more highly branched.
• What is a monosaccharide?

  A single sugar molecule
• What are examples of monosaccharides?

  Glucose, galactose, and fructose
• What is the structure of glucose?

  Glucose has a ring shape
• What is the chemical formula of glucose?

  $C_6H_{12}O_6$