Biol 190 Unit 2 Chapter 6

Identify the macromolecule, polymer, dimer, and monomer.

Macromolecule: Carbohydrates

Polymer: polysaccharides (glycogen, starch, cellulose)

Dimer: disaccharide (e.g. sucrose, lactose, maltose)

Monomers: monosaccharide (e.g. glucose, fructose, galactose)

How do we get most of our carbohydrates?

Through eating them

What is the formula for carbohydrates (simple sugars)?

C₁(H₂O) 1:2:1

How do carbon skeletons vary?

Linear structure or ring structure (more stable-\> more common in monosaccharides)

What are hexoses?

Six-carbon sugars; C6H12O6; Ex: glucose, galactose, and fructose are examples of structural isomers

How is a disaccharide formed?

Two monosaccharides link together through a dehydration reaction

What are the covalent bonds between monosaccharides?

Glycosidic linkages

What is the polysaccharide structure and function determined by?

It's determined by its sugar monomers and the positions of its glycosidic linkages

What is the first example of a polysaccharide?

Glycogen: used by animals to store energy and is broken down to release glucose when you need energy

What is the second example of a polysaccharide?

Starch: used by plants to store energy; Potatoes and grains are major sources of starch in our diet

What is the third example of a polysaccharide?

Cellulose:

1\. The most abundant organic compound on Earth

2\. Forms cable-like fibers in plant walls (structural role)

3\. Cannot be broken by any enzyme produced by animals (cannot break the linkages)

Why do humans consume cellulose?

Fiber (helps clean intestines)

How do cows break down cellulose?

Bacteria in cow's stomach digests the cellulose and gives it to the cow

What are the functions of carbohydrates?

1. Energy (mono and disaccharides)
2. Energy storage: such as starch (polysaccharide)
3. Structural molecule to give shape to organisms (ex. cellulose)
4. Supply carbon: for synthesis of other compounds

Identify the macromolecule, polymer, and monomer.

Macromolecule: Lipids (e.g. TG, PL, Steroids)

Polymer, Monomer: NA (lipids don't covalently link together)

Lipids are the only class of macromolecules that are \___________

Hydrophobic

What are triglycerides?

Oil and fats; a glycerol molecule joined with three fatty acid molecules via dehydration reactions; stored in adipose tissue

What is the function of triglycerides?

\-storage of energy

\-insulation and protection

\-most common type and storage unit of lipid

\-solid @ room temp= fat ; liquid=oil

How long does it take monosaccharides, polysaccharides, and triglycerides to be used up for energy?

1-2 hours, 24 hours, and months respectively

Fatty acids are a \________________

Hydrocarbon chain

How do fatty acids vary?

\-Saturated: maximum number of hydrogen atoms possible, no double bonds, solid at room temp

\
\-Unsaturated: One or more double bonds, are kinked do not stack, liquid at room temp

Hydrocarbon bonds are...

Rich in energy

In triglyceride synthesis...

3 dehydration reactions join fatty acids to glycerol

What is the covalent bond that holds a triglyceride together?

Ester linkages

Why do fats stick together (aggregate) when placed into an aqueous solution?

Hydrophobic interactions

What are essential fatty acids?

Certain unsaturated fatty acids are not synthesized in the human body; must be supplied in diet (omega-3 fatty acids, required for normal growth)

What are the functions of fat?

1. Energy storage
2. Cushions organs and insulates the body
3. Fat supplies essential fatty acids (EFAs)
4. Carries "fat-soluble vitamins" around the body
5. Necessary for maintaining healthy skin
6. Plays a central role in proper eyesight and brain development

What are trans fat?

Manmade oil to fat through hydrogenation

What is hydrogenation?

1. Adds hydrogen
2. Converts unsaturated fats to saturated fats
3. Makes liquid fats solid at room temperature
4. Increase bad cholesterol levels
5. Will be off the market soon

What are phospholipids?

Composed of three parts: fatty acids, glycerol, polar group; predominant molecule in cell membranes

How do phospholipids differ from triglycerides?

1. Phosphate functional group (polar group)
2. Unsaturated fatty acids (at least one for fluidity)

Are phospholipids amphiphilic?

Yes/ amphipathic

What happens when phospholipids are added to water?

Phospholipid bilayer forms spontaneously

What are the hydrophobic and hydrophilic regions of phospholipids?

Hydrophobic: fatty acid tails; Hydrophilic: Polar phosphate heads

What is the structure of steroids?

Carbon skeleton of four fused rings

What is the function of steroids?

Steroids vary in the functional groups attached to this set of rings, which in turn affect their function

What is the most common steroid in humans?

Cholesterol:

\-gives structure to cell membranes, keeps them "fluid"

\-Precursor to steroid hormones (reproductive hormones)

Do steroids contain fatty acids/ provide energy?

No

Are steroids soluble in water?

No, all lipids are insoluble in water

Do we make sex hormones?

No, we create it by eating cholesterol