Physio Lecture: Exam 1

cells

basic structural and functional units of life

• all living organisims are cellular in nature

  • amoebas and bacteria are unicellular

  • humans, animals, and big plants are multicellular

• 50-100 trillion in the human body

what are the 3 regions of a cell?

plasma membrane, cytoplasm, and the nucleus

plasma membrane (plasmalemma)

outer thin and flexible membrane of a cell that separates the intracellular compartment/fluid from the extracellular compartment/fluid like interstitial fluid and plasma

plasma membrane structure

made of a double layer of lipids (phospholipids/phospholipid bilayer) that have has cholesterol and glycolipids

• integral and peripheral proteins are embedded throughout

the plasma membrane has ___ to transport ions such as ___ and ___

• structurally, ___ and ___ pass through the cell membrane easily

• ___ hormones (i.e ___ and ___) pass through easily

  • structurally from cholesterol

• ___ hormones have a diff. structure (___ size) → doesn’t pass through easily

channels…sodium… potassium chloride

• cholesterol…lipids

• sex…testosterone…estrogen

• protein … larger

integral proteins

receptor of protein hormones (i.e insulin and neural transmitters)

• most abundant proteins in the membrane

• most extend entirely throughout the membrane/transmembrane

• some protrude from one side of the membrane

• act as RECEPTORS

clinical point regarding integral proteins

any mutation or alteration to receptor → hormonal disorder: type 2 diabetes/hyperglycemia

• ultimately a receptor problem where insulin can’t bind to protein receptor

type 1 diabetes is a cause of ___ where there is an insulin ___

autoimmune disorders … insulin deficiency

peripheral proteins

function to isolate and seperate the cell membrane from the cytoplasm

• mostly on the cytoplasmic side

  • support the cytoplasmic side of membrane via network of filaments

phospholipids

most abundant lipids in the plasma membrane

• hydrophillic heads

• hydrophobic tails

hydrophillic heads of phospholipids

• attach to water (main constituent of intra- and extracellular fluids)

• lie among the inner and outer faces of the membrane

• polar, nitrogenous compound, phosphate bridge, glycerol

hydrophobic tails of phospholipids

avoid water and line up in the center of the membrane

• nonpolar

• saturated and unsaturated fatty acids

glycocalyx

sugar covering or cell coat that covers cell membranes externally

glycocalyx are short ___ of ___(sugars) projected out from the ___ surface of glyco___ or glyco___

• work to bring ___ binding and ___

chains … carbohydrates… external … proteins/lipids

• cell-to-cell binding … recognition

glycocalyx are produced by ___ and also help bind ___ onto the ___ surface

corneal epithelial surface cells … mucins … corneal

the plasma membrane serves as an ___ cell ___ against substances and forces ___ of the cell → protecting the cell from ___

external … barrier … outside → external trauma

the plasma membrane’s ___ facing ___ act as receptors (for hormones, neurotransmitters, etc.) and help in cell-to-cell recognition

externally … proteins

the plasma membrane helps with the ___ of substances into/out of the cell

• transports ___(sodium, potassium, calcium), ___, and ___ via channels

  • ___proteins as receptors

transport

• ions … substances … fluids

• integral

the plasma membrane is a ___ permeable barrier → ___ substances pass between ___/___cellular fluids and others are prevented

selective → some … intra/extra

passive process

process where substances pass freely through lipid bilayer down the concentration gradient or from a more concentrated region to a less concentrated region until equilibrium is reached

• diffusion

• no ATP needed

diffusion

natural movement of small, uncharged molecules (i.e oxygen, CO₂, and fat soluble molecules) across the membrane from higher to lower concentrations

active process

process where substances move against a concentration gradient from a lower to higher concentration

• ATP is needed

active transport

when larger water-soluble/charged molecules (i.e glucose, amino acids, and ions) are transported via a pump/carrier and involve integral proteins and needs ATP or cellular energy

vesicular or bulk transport

mechnism via many large particles and macromolecules pass through

• exocytosis and endocytosis