Lipids

Macromolecules are large organic carbon compounds Carbohydrates (Cell Energy) Proteins (Enzyme Activity) Nucleic Acids (Gene Expression/ Cell Differentiation) Lipids

Monomer?: Glycerol Head & Fatty Acid Tail

Long term energy storage Composition of cells (cell membrane)

All cells contain: Cell membrane Cytoplasm Genetic material Ribosomes

Regulate passage of material into/out of cell Provide limited support & protection to cell Communicate with other cells

Made of double layer of phospholipids phosphorus (hydrophilic) “head” lipid (hydrophobic) “tail”

Protein Channels allows large molecules to pass through Carbohydrate antennae picks up messages from outside the cell Cholesterol lipids that prevent freezing

Cells need various molecules to function Transporting molecules is essential to life

Honors Biology

Transport of substances that does NOT require energy expenditure Diffusion Facilitated diffusion Osmosis

Molecules moves from high concentration to low concentration (down the concentration gradient)

Molecules that easily diffuse: O2 and CO2 (nonpolar molecules)

Some molecules need help entering the cell too big or polar Proteins help molecules w/o using energy

Glucose (large molecule)Water (polar molecule)

When solutes are unable follow the concentration gradient across the membrane water responds. By changing the water concentrations inside and outside a cell, equilibrium may be reached

Movement of H2O across a semi-permeable membrane

Hypertonic: Water concentration inside a cell is higher than outside the cell Isotonic: Water and solute concentrations in a cell are equal Hypotonic: Water concentration inside a cell is lower than outside the cell

Water moves out of the cell Animal and plant cells shrivel (plasmolysis)

No net movement of water Animal and plant cells are normal (flaccid)

Water moves into the cell Animal cell membranes burst (cytolysis) Plant cell walls prevent bursting (turgid)

Some molecules move against the conc. gradient This requires an energy input (ATP) from a cell

Active transport brings in/takes out large molecules Food, Solids, or Liquids

Substances are expelled from the cell Molecules are contained within a vesicle Vesicle fuses with the inner cell membrane Contents are expelled to outside environment

Substances (food particles) are engulfed into the cell Cell surrounds food Membrane connects forming a vesicle Food is taken into the cell

Substances (liquid particles) are engulfed into cell Same as phagocytosis

Molecules bind to membrane receptors protein Substance of interest migrates into coated pit Pit forms a vacuole Receptors migrate back to membrane