Organic Molecules and Cell Structure: Proteins, Lipids, and Membrane Functions

Protein function

Structural support & facilitate chemical reactions.

Nucleic acid function

Encode & transmit genetic information.

Carbohydrates function

Provide energy source & make up cell wall in non-animal cells.

Lipids function

Cell membranes, energy storage, & act as signaling molecules.

Phospholipid makeup

Made up of glycerol backbone attached to a phosphate group & 2 fatty acids.

characteristics of Saturated fatty acids

Have no C-C double bonds, straight

characteristics of Unsaturated fatty acids

Have C-C double bonds, bent

Cytoplasm function

Material inside cell membrane that surrounds the organelles and allows for reactions, storage, & facilitating intracellular transport.

Cytosil function

Fluid in the cytoplasm that helps the organelles function and gives them structure.

Nucleus function

Houses genome/DNA & RNA synthesis takes place.

Endoplasmic reticulum function

Involved in protein and lipid synthesis.

Golgi apparatus function

Modifies lipids and proteins, sorts them and transports them, and is where carbs are added to proteins & lipids.

Lysosome function

Degrade/digests unneeded macromolecules and involved in cell death (apoptosis).

Mitochondria function

Use energy from sugars and convert it to ATP (adenosine triphosphate) which drives many chemical reactions.

Integral membrane proteins characteristics

Permanently associated with cell membranes, hydrophibic & hydrophillic, polar & nonpolar areas

Peripheral membrane proteins

Temporarily associated with the lipid bilayer and can be easily separated from the membrane, hydrophillic, connected to phospholipid heads

Fluid mosaic model

Lipids, proteins, & carbs coexist in the membrane and move through it.

prokaryotic cells lack:

nucleus and membrane-bound organelles

trygliceride chemical structure

3 fatty acid chains, glycerides

cholestrol chemical structure

4 carbon rings, hexagonal shape

how double bonds affect membrane fluidity:

more = more fluid

less = less fluid

why double bonds affect fluidity (in fatty acids)

double bonds create bends in fatty acid tails which prevents packing, allowing for more fluidity

how length of fatty acids affects membrane fluidity:

longer = less fluid

shorter = more fluid

why length affects fluidity (in fatty acids)

longer length means more van der waals bonds creating tighter structures thus decreasing fluidity

how temperature affects fluidity

higher = more fluid

lower = less fluid

why temperature affects fluidity

added heat means added energy which disrupts van der waals bonds between fatty acid tails

how does cholestrol affect fluidity

acts as regulator or buffer

high temps = decrease fluidity

low temps = increases fluidity

why cholestrol affects fluidity

it adapts to molecule's needs. at higher temperatures, it fills in gaps in phospholipid stabilizing the membrane, at low temps it prevents tight packing

phospholipid heads are..

polar, hydrophilic

phospholipid tails are..

nonpolar, hydrophobic