Biology Notes

Pinocytosis

"Cellular drinking", the cell gulps droplets of fluid into tiny vesicles, (not specific) takes in all solutes dissolved in the droplets

Phagocytosis

"Cellular eating", a cell engulfs a particle by wrapping extensions (pseudopodia) around it and packing it within a membrane-enclosed sac large enough to be called a vacuole

Hydrophobic

"Water-fearing"; pertaining to nonpolar molecules, or parts of molecules, that do not dissolve in water. Tail=non-polar

Hydrophilic

"Water-loving"; pertaining to polar (charged molecules), or parts of molecules, that are soluble (dissolve) in water. Head=polar

Active transport

A cell must expend energy to move a solute against its concentration gradient (toward where the solute is more concentrated) This allows a cell to maintain internal concentrations of small molecules and ions that are different from concentrations in its surroundings

Fluid mosaic

A description of membrane structure, depicting a cellular membrane as a mosaic of diverse protein molecules embedded in a fluid bilayer made of phospholipid molecules.

Unsaturated fatty acid

A fatty acid possessing one or more double bonds between the carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.

Transport proteins

A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.

Endocytosis

A transport process (opposite of exocytosis) Cell takes in large macromolecules, a depression in the plasma membrane pinches & forms a new vesicle enclosing the material outside of the cell. 3 kinds: phagocytosis, pinocytosis, & receptor-meadiated endocytosis.

Structure of a cell membrane

Bilayer of phospholipids with embedded and attached proteins- fluid mosaic

Energy

Capacity to cause change or to perform work

Passive transport

Cells that do not have to do work when molecules diffuse across its membrane. Simple diffusion. Without energy.

Flexible membrane

Cold temperature

Osmosis

Diffusion of water across a membrane. Passive (without energy). Water is the most important substance that crosses membranes by passive transport. H2O is going to move from an area of high concentration to an area of low concentration

Unsaturated

Double-bonds, kinks don't allow for compaction

The greater number of transport proteins for a solute in a membrane

EQUALS the faster the solute's rate of diffusion across the membrane

Kinetic energy

Energy of motion

Potential energy

Energy that matter processes as a result of its location or structure

ECF

Extra cellular fluid. Outside of the cell

Turgid

Firm. Needs a net inflow of water

Hypertonic solutions

Have a higher concentration of permeating solutes than the ICD in a hypotonic solution. Cells lose lore water than they gain & shrivel. hyper=plasmolyzed. Water balance

Hypotonic solutions

Have a lower concentration of non-permeating solutes than the ICF. Cells gain more water than they lose. May cause cell to swell & rupture. hypo=less,blow. Less solutes in solution. Water comes into the cell. Plant cells=turgid

Isotonic solutions

Have a solute concentration equal to ICF. Cells gain and lose EQUAL amounts of water and maintain a normal volume. iso=same. Plant cells=flaccid

Thermal motion

Heat. Molecules vibrate and move randomly

Receptor-mediated endocytosis

Highly selective, receptor proteins for specific molecules are embedded in regions of the membrane that are lined by a layer of coat proteins

Stable membrane

Hot temperature

Cholesterol

In between the tails

ICF

Intra cellular fluid. Inside of the cell

Selective permeability

Membranes that allow some molecules to pass through more easily than others

Flaccid

Normal/limp

Phospholipids

Part of the membrane structure and function of the cell. A molecule that is a part of the inner bilayer of biological membranes, having a polar hydrophilic head ,and a non-polar hydrophobic tail.

Facilitated diffusion

Polar (charged) substances can move across a membrane with the help of specific transport proteins. Without transport protein the substance cannot cross the membrane or it diffuses across it too slowly. Passive transport (no energy required)

Chemical energy

Potential energy available for release in a chemical reaction, most important type of energy for living organisms, can be transformed to power the work of a cell

Osmoregulation

Prevents cell from excessive uptake of excessive loss of water. Turgid central vacuoles (in plants: hold H2O). Contractive vacuoles in the same protists hold of expel water. Transport proteins. The control of water balance.

Glucose

Requires a transport protein to enter of leave the cel

Plasmolyzed

Shriveled

Saturated

Single-bonds, tightly packed

Process of Active transport

Solute molecules on the cytoplasmic side of the plasma membrane attach to specific binding on the transport protein. ATP transfers a phosphate group to the transport protein, the protein changes shape, solute is released on the other side of the membrane. Phosphate group detaches, transport protein returns to previous shape

Tonic

Solution. Factors: concentration of solutes in solution

Factors affecting diffusion rate

Temperature- temp rides & speeds up motion of molecule. Molecular weight- heavier. Membrane surface area. Membrane permeability. Pressure. Steepness of the concentration gradient.

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water

Exocytosis

The export of bulky material (proteins or polysaccharides) Transport vesicle filled with macromolecules buds from Golgi apparatus & moves to the plasma membrane, vesicle fuses with the cell membrane, vesicle contents spill out, vesicle membrane becomes part of the cell membrane. Example: tears

Diffusion

The tendency for particles of any kind to spread evenly in an available space. Process: molecules move from an area of higher concentration to an area of lower concentration

Heat

Thermal energy, associated with the random movement of atoms of molecules

SImple diffusion

Unassisted diffusion of solutes through the plasma membrane

Aquaporin

Water transport channels that allow for very rapid diffusion of water through a cell membrane. Single allows up to 3 billion water molecules per second. Found in cells that have high water transport needs (blood cells, kidney cells, & plant cells)

Concentration gradient

When gradient exits substances tend to move from there they are more concentrated to where they are less concentrated