Bio 101 Chapter 6 Exam 1

What is a characteristic true of the 3 different lipids we learned about?

What is a characteristic true of the 3 different lipids we learned about?

There are all insoluble and hydrophobic

Saturated v unsaturated fatty acid tails.

Saturated= Maximum number of H’s

Unsaturated= Some kind of kink (Double or Triple Bond)

Recognize general structure of steroid and give some examples of biological roles of steroids.

Steroids are bulky four-ring structures that differ from one another by the functional groups attached to the rings. estrogen and testosterone are biological examples of steroids they determine one’s biological gender.

Why are fats called triglycerides?

Fats are called triglycerides because they are made up of three fatty acids and glycerol.

Which bond links glycerol/Fatty acids?

ester linkage

Why are phospholipids called amphipathic?

They are both hydrophobic and hydrophilic

Lipid Functions

1. Store Chemical Energy

2. Act as pigments that capture/respond to sunlight

3. Serve as signals between cells

4. Form waterproof coatings on skin and cells

5. Act as vitamins in cellular processes

Factors determining membrane permeability.

1. Length of hydrocarbon tails

   1. Longer chain= less permeable

2. Saturation state of hydrocarbon tails

   1. More saturation= less permeable

3. Cholesterol

   1. Increase cholesterol= less permeable

4. Hydrophobic Reactions

   1. Increase Hydrophobic reactions= less permeable

5. Temperature

   1. Increase temperature= more permeable

Isotonic solution

Equal/Solute

No net movement of water

Hypertonic solution

More/solute

(solution has more solute than in the cell)

Cell will shrivel up

water flows out of the cell because it flows from low solute to high solute

Hypotonic Solution

Less/solute

Solution has less solute

Cell will swell and can burst

Water flows into the cell because it flows from low solute to high solute

What are the four levels of permeability

1. Small non polar molecules- O2

2. Small uncharged polar molecules- H2O

3. Large uncharged polar molecules- C6H12O6

4. Small ions- K+

Why are small ions the hardest to get through the membrane?

Ions are super charged, and fatty acid tails are non polar. The ions go ip to the head and they are fine, but then they are sent away by the tails.

Diffusion

Spontaneous movement of molecules or ions from areas of high concentration to low concentration

Equilibrium

No net movement. Things do not stop moving here.

Osmosis

The movement of water across a selectively permeable membrane. Flows form low solute to high solute.

Facilitated diffusion

Transmembrane proteins assist passive transport

Integral proteins

Span the entire length of the membrane. Take part in facilitated diffusion.

Electrochemical gradient

Establish both concentration gradient and charge gradient.

Steps to the Sodium potassium pump

1. Three sodium ions from the inside of the cell bind to the sites on the protein that have an affinity for sodium ions.

2. A phosphate group from ATP binds to the protein, and the protein changes shape.

3. The opening shifts to the outside of the cell, and the sodiums are released to the outside.

4. Two potassium from the outside of the cell then bind to the sites on the protein that have an affinity for potassium ions.

5. When the potassium binds, the phosphate is kicked off of the protein and the pump returns to its original shape.

6. The potassiums are released to the inside of the cell and the process starts over.