Cells

Structure of the Cell Membrane

A single phospholipid molecule as the head, and two side-by-side chain of fatty acids as the tail

Amphipathic Molecules (Phospholipid)

a molecule containing a hydrophobic and hydrophilic region

Intracellular fluid

Fluid interior of the cell

Extracellular Fluid

Fluid environment outside the enclosure of the cell membrane

Interstitial Fluid

Extracellular fluid not contained within blood vessels

Integral protein

A protein that is embedded in the membrane

Channel Protein

An integral protein that selectively allows particular materials (like ions) pass into or out of the cell

Cell Recognition Proteins

A type of integral protein which serves to mark a cell’s identity so that it can be recognized by other cells

Receptor

A type of recognition protein that can selectively bind a specific molecule outside the cell

Ligand

A specific molecule that binds to and activates a receptor

Glycoproteins

A protein that has carbohydrates molecules attached to it

Glycocalyx

A fuzzy appearing coat around the cell formed from glycoproteins and other carbohydrates attached to the cell membrane

Functions of Glycocalyx

Allows cells to bind to each other, may contain receptors for hormones, or have enzymes that break down nutrients

Peripheral proteins

Perform specific function for the cells. Can be found on the inner or outer surface of the lipid bilayer

Passive transport

Movement of substances across the membrane without the expenditure of cellular energy

Active transport

Movement of substances across the membrane using energy from ATP

Concentration gradient

The difference in concentration of a substance across a space

Diffusion

The movement of particles from an area of higher concentration to an area of lower concentration

Simple diffusion

A mechanism of moving molecules across the cell membrane from the side where they are more concentrated to the side, where they are less concentrated

Facilitated diffusion

A process of substances that cannot cross the lipid by layer due to their size charge and/or polarity

Osmosis

The diffusion of water through a semipermeable membrane

Isotonic

two solutions that have the same concentration of solutes (equal tension)

Hypertonic

Solutions that are said to have a higher concentration of solute than another solution

Hypotonic

Solutions that are said to have a lower concentration of solute than another solution

Filtration

Uses a hydrostatic pressure gradient that pushes fluid and the solute within it from a higher pressure area to a lower pressure area

Symporters

Secondary active transporters that move two substances in the same direction

Antiporters

Secondary active transport system that transport substances in opposite directions

Endocytosis

A process of cell ingesting material by developing it into a portion of its cell membrane, then pinching off that portion of membrane

Phagocytosis

The endocytosis of large particles

Pinocytosis

Brings fluid containing dissolved substances into a cell through membrane vesicles

Receptor mediated endocytosis

Endocytosis by a portion of the cell membrane that contains many receptors that are specific for a certain substance

Exocytosis

an active transport process where a cell moves large molecules or waste out through its membrane

Organelles of the Endomembrane system

Endoplasmic reticulum, Golgi apparatus, and vesicles

Endoplasmic reticulum (ER)

Provides passages throughout the cell that function in transporting, synthesis, and storing materials

Rough endoplasmic reticulum (RER)

A membrane dotted with embedded granules (ribosomes) giving RER a bumpy appearance

Smooth endoplasmic reticulum

Synthesize lipids, such as phospholipid and steroid hormones, performs a detoxification role breaking down certain toxins

Golgi apparatus

Responsible for sorting modifying and shipping off products that come from the rough ER

Lysosomes

Contains enzymes that breakdown and digest, unneeded cellular components; important for breaking down foreign material

Autophagy

(Meaning self-eating) is the process of cell digesting its own structures

Organelles for energy production and detoxification

Mitochondria and peroxisomes

Mitochondria

An organelle that performs a biochemical reaction of cellular respiration that converts energy stored in nutrient molecules into ATP for the cell

Peroxisomes

A membrane bound of organelle that contains mostly enzymes (like lysosomes)

Function of Peroxisomes

Lipid metabolism and chemical detoxification

Reactive Oxygen Species (ROS)

Highly reactive products of many normal cellular processes (ex. Mitochondrial reactions that produce ATP and oxygen metabolism)

Cytoskeleton

A group of fibrous protein that provide structural support for cells

Types of protein filament in cytoskeleton

Microtubules, microfilaments, intermediate filaments

Microtubule

Thickest of the 3 filaments; composed of subunits of protein called tubulin

Two types of cellular appendages important for motion made up by microtubules

Cilia and Flagella

Cilia

Moves waste material (mucus and bacteria) upward through the airways away from the lungs and toward the mouth

Flagella

An appendage larger than cilia and specialized for cell locomotion

Microfilaments

Thinner type of cytoskeleton filament

Actin

Primary component of microfilaments that contribute to a large proportion of muscle tissue and along with the protein myosin that are responsible for muscle contraction.

Intermediate filament

Made up of keratin; maintains cell shape and structure, but resists tension that forces cells apart.

Nucleus

The largest organelle, and is considered the control center of the cell since it stores all of the genetic material to make proteins

Nuclear envelope

A membranous covering that consists of two adjacent lipid bilayers surrounding the nucleus

Nuclear pores

A tiny passageway for the passage of proteins, RNA, and solutes between the nucleus and cytoplasm

Pore Complexes

A protein that lines the nuclear pores to regulate the passage of materials into and out of the nucleus

Nucleolus

a region of the nucleus that is responsible for manufacturing the RNA necessary for the construction of ribosomes

Nucleosome

A single, wrapped DNA histone complex