Anatomy & Physiology: Chapter 3 - The Cell

Cell Metabolism

all the chemical reactions a cell does to stay alive; includes anabolic, catabolic, and oxidation-reduction reactions

Anabolic Reactions (cell metabolism)

build bigger molecules using energy

Catabolic Reactions (cell metabolism)

break molecules down to release energy

Oxidation-Reduction Reactions (cell metabolism)

transfer energy by moving electrons between molecules

Substance Transport

moving compounds into, out of, or within a cell

Communication

cells communicate with themselves, with their surrounding environment, and with other cells in the body

Cell Reproduction

many cells undergo cell divison

Plasma Membrane

the cell’s outer layer that keep it separate from its surroundings (like a fence), supports its structure, communicates with other cells, and controls what enters and leaves.

Cytoplasm

contains cytosol, organelles, cytoskeleton, nucleus

Cytosol

fluid inside the cell where organelles float

Organelles

specialized “mini organs” inside the cell that do specific jobs

(like mitochondria making energy)

Cytoskeleton

gives the cell shape and support

Nucleus

cell’s control center, holds DNA

Eukaryotic

contrains a nucleus

Prokaryotic

contains no nucleus (bacteria)

Intracellular Space (plasma membrane)

space within the cells that contains cytosol

Extracellular Space (plasma membrane)

space outside the cells that contains extracellular fluid (ECF)

Intracellular Fluid (ICF)

the fluid inside cells, a watery gel containing proteins, dissolved solutes, and RNA

Extracellular Fluid (ECF)

the fluid outside cells

Phosopholipid Bilayer

forms an effective barrier between the ECF and cytosol

Polar phosphate “heads”

hydrophilic (water loving) head of a phosopholipid

Nonpolar fatty acid “tails”

hydrophobic

plasma membrane

“fence” or “skin” of cell

Mosaic: lipids, phospholipids, proteins, carbohydrates; this diversity of what’s able to move around within plasma membrane

Fluidity: plasma membrane is not a rigid wall; membrane changes constantly as things in the bilayer move around in different directions

Membrane proteins

carry out plasma membrane’s functions and give different cell types unique properties.

integral proteins

span entire width of membrane; type of membrane protein

transmembrane proteins

span entire width of the membrane; type of membrane protein

peripheral proteins

found on only 1 side of membrane, type of membrane protein

(can be anchored in place by cytoskeleton or floating freely in phospholipid bilayer)

Channel membrane proteins

substances pass through the membrane

Carrier membrane proteins

substances are transported through the membrane

Receptor membrane proteins

ligands bind to the receptor to trigger a change in the cell

Enzyme membrane proteins

catalyze (speed up) chemical reactions while staying in membrane

Structural support membrane proteins

provide cell shape and structural support

Linker membrane proteins

hold adjacent cells in a tissue together

cholesterol

keeps structure of the plasma membrane in tact when temperature changes

diffusion

solute high to low concentration

simple diffusion

nonpolar solutes and gases pass straight through the phospholipid bilayer without the need for a membrane protein

facilitated diffusion

charged or polar solutes cross the phospholipid bilayer through a channel or carrier protein

osmosis

solvent (water) moves low to high concentration

water can cross the plasma membrane:

1. through aquaporins (water channels)

2. between phospholipids in membrane due to water’s small size

two pressures cause water movement to stop:

1. osmotic pressure

2. hydrostatic pressure

osmotic pressure

the pressure that must be applied to a solution to prevent water from moving into it by osmosis

hydrostatic pressure

force that water exerts on the walls of the container

when both sides have equal volume: hydrostatic pressure is equal

when water level rises: hydrostatic pressure increases

osmotic gradient

difference between the osmotic pressures in sides with unequal volume

osmosis stops when the hydrostatic pressure in the side with more volume reaches the value of osmotic gradient

Isotonic ECF vs. cytosol ability to cause osmosis?

same, so no water movement

hypertonic ECF vs. cytosol ability to cause osmosis?

greater, so cell loses water (can crenate)

hypotonic ECF vs. cytosol ability to cause osmosis?

lesser, so cell gains water and swells (can rupture/lyse)

active transport

requires energy (ATP) because solutes go low to high

transport vesicles

transport large particles into or out of cell

vestibular transport

transport using vesicles that REQUIRES ATP to fuel the process

endocytosis

brings substances into the cell

phagocytosis

cells eat big particles (bacteria, dead cells, or parts of cells)

pinocytosis

bring nutrients and other substances into the cell

receptor-mediated endocytosis

type of pinocytosis that results in transport vesicles containing a high concentration of a specific substance

exocytosis

moves substances out of the cell

transcytosis

moving molecules across a cell in from one side to the other, then releasing from cell’s other side

primary active transport

movement of solute against concentration gradient using ATP

secondary active transport

RER

makes and folds proteins that are usually secreted out of the cell or sent to the membrane, RIBOSOMES

SER

makes lipids, detoxifies chemicals, stores calcium

Cystic Fibrosis

RER’s ability to dispose of misfolded proteins is detrimental

free ribosomes

float in cytoplasm, make proteins that stay in cell

bound ribosomes

attached to RER and make proteins that are exported out or put in membranes

golgi apparatus

modify, sort, and package proteins and lipids produced by ER for transport

“post office”

lysosomes

break down/digest unwanted materials (worn out organelles, bacteria, cellular waste)

“digestive system”

Gaucher’s Disease

missing enzyme that breaks down glycolipids which accumulate in cells of blood, spleen, liver, lungs, bone, and sometimes brain. fatal in infancy/early childhood

Tay-Sachs Disease

missing enzyme that degrades glycolipid in the BRAIN, fatal by 4-5 yrs old

Hurler Syndrome

missing an enzyme that digests certain large