Cell Physiology Study Guide

Fluidity

Increases with temperature, unsaturated fatty acids, and short fatty acids

Osmolality

Number of particles in solution per kg of solvent

Fick's Law

Rate of molecule movement proportional to concentration gradient and inversely proportional to membrane thickness

Cross-Bridge Cycling

ATP binding, hydrolysis, weak and strong cross-bridge formation, power stroke, and rigor state

Striated Muscle

Muscle with sarcomeres and thin and thick filaments

Carbohydrates

Component of plasma membrane

Cholesterol

Regulates membrane fluidity based on temperature and concentration

Fluid Phase Endocytosis

Non-selective movement of substances into the cell via vesicle

Protein Synthesis

Begins on ribosomes and involves signal sequence, SRP, translocon, and cleavage

Nucleus

Stores genetic information and regulates DNA and RNA

Smooth ER

Involved in lipid synthesis and calcium storage

Microtubules

Polar filaments involved in cell division and growth

mRNA Degradation

Regulation of mRNA stability and degradation

Water Distribution

Male TBW=60%, Female TBW=50%, ECF=40%, ICF=60%

Osmolarity

Number of particles in solution per unit volume of solvent

Bulk Electroneutrality

Equal number of positive and negative charges in solution

Secondary Active Transport

Energy from existing gradients used to move solutes against gradient

Countertransporters

Move solutes against concentration gradient in opposite direction

Pore

Large nonselective channel in plasma membrane

Skeletal Muscle

Multinucleated muscle with motor units and sarcomeres

Ca Activation

Calcium binds to troponin, exposing actin binding site

Pharmacological Agents

Tetanus toxin, botulinum toxin, dendrotoxin, etc. affecting synaptic transmission

MLCK

Phosphorylates myosin light chains in smooth muscle

Claude Bernard

Proposed the two milieu: interior and exterior

Homeostasis

Control of vital parameters at multiple levels

Negative Feedback

Mechanism of homeostasis involving sense, compare, amplify, and effect

Equilibrium

System in balance with zero net force and no energy required

Steady-State

System with non-zero net force and energy required to maintain

Milieu

Internal and external environment

Sense

Detection of vital parameter

Compare

Comparison of input and internal set point

Amplify

Increase effect via output signal

Effect

Output signal to counteract input signal

Phospholipids

Component of plasma membrane

Cholesterol

Component of plasma membrane that regulates fluidity

Sphingolipids

Component of plasma membrane

Proteins

Function as receptors, transporters, enzymes, etc. in plasma membrane

Peripheral Proteins

Category of membrane proteins

Integral Proteins

Category of membrane proteins

Receptor Mediated Endocytosis

Selective movement of target molecules into the cell via ligand-receptor binding

Golgi Apparatus

Stores and modifies proteins

Rough ER

Studded with ribosomes, involved in protein translation and calcium storage

Lysosome

Contains degenerative enzymes and has highly acidic interior

Mitochondria

Involved in TCA cycle, oxidative phosphorylation, and apoptosis

Cytoskeleton

Provides structure, adhesion, support, and motility

Constitutive Pathway

Unregulated secretion of membrane proteins or constantly needed proteins

Regulated Pathway

Highly regulated secretion of hormonal or neural signals

Intermediate Filaments

Provide tensile strength and form adhesion plaques and desmosomal junctions

Thin Filaments

Polar filaments involved in polymerization and ATP hydrolysis

Thick Filaments

Filaments with helical tails and globular heads involved in force generation

Gap Junctions

Channels between cells made of connexins for rapid signal propagation

Tight Junctions

Watertight seals between adjacent cells, found in epithelial tissues

Adhering Junctions

Connect cells to actin filaments and extracellular matrix

Desmosomes

Connect cells and organize intermediate filaments

Endocrine Signaling

Signal secreted into blood and carried to target organs or tissues

Paracrine Signaling

Signal secreted by neighboring cell in vicinity of target cell

Autocrine Signaling

Cell signaling itself

Juxtacrine Signaling

Direct contact between signaling cell and receiving cell

G alpha S

Stimulatory intercellular signaling molecule that activates adenylate cyclase

G alpha I

Inhibitory intercellular signaling molecule that blocks adenylate cyclase

G alpha q

Intercellular signaling molecule that activates PLC beta

Receptor Tyrosine Kinase

Ligand binding causes receptor dimerization and downstream signaling

Nuclear Receptor

Contains hydrophobic AAs or sterol nucleus, functions as transcription factor

Central Dogma

DNA to RNA to Protein

Chromatin Remodeling

Alteration in chromatin structure to regulate gene expression

Transcription Factors

Regulate DNA transcription, including TFIID and Pol II

Post Translational Modification

Splicing, capping, cleavage, and polyA tail addition to mRNA

Nucleocytoplasmic Transport

Movement of RNA and proteins between nucleus and cytoplasm

Effective Osmolyte

Non-permeant solute that drives water movement

Tonicity

Effective osmolality that determines water movement

Osmotic Pressure

Pressure created by osmotic gradient that drives water movement

Oncotic Pressure

Osmotic pressure generated by proteins in plasma

Hydrostatic Pressure

Pressure exerted by stationary fluid

Primary Active Transport

ATP used to move solutes against concentration gradient

Passive Transport

No ATP used, solutes move down concentration gradient

Na/K Pump

Active transport of Na and K ions to maintain osmotic equilibrium

Cotransporters

Move solutes against concentration gradient in same direction

Channel

Selective channel that opens with ligand or voltage

Carrier

Selective channel that opens at one side and can be active transporter

Epithelial Transport

Movement of ions across epithelium via voltage and chemical gradients

Sarcomere

Contractile unit of skeletal muscle with thin and thick filaments

Thin Filaments

Actin filaments with tropomyosin and troponin complexes

Thick Filaments

Myosin filaments with heads for cross-bridge cycling

ECC of Skeletal Muscle

Depolarization-induced Ca2+ release and termination of contraction

Smooth Muscle

Innervated by autonomic nervous system, with multiunit and unitary innervation

Smooth Muscle Cross-Bridge Cycle

MLCK phosphorylates myosin light chains to activate contraction

ECC of Smooth Muscle

Calcium binds to calmodulin, activates MLCK, and triggers contraction

Vasodilation

Caused by lack of O2, excess CO2, low pH, adenosine, etc.

Vasoconstriction

Caused by increased Ca, norepinephrine, angiotensin, etc.

Cardiac Muscle

Striated muscle with syncytium and ECC involving CICR

ECC of Cardiac Muscle

AP triggers opening of voltage gated Ca channels and CICR

Digitalis

Increases force of contraction by blocking Na/K ATPase

Electrical Synapse

Gap junctions for immediate bidirectional communication

Chemical Synapse

NT release and binding to receptors for communication

Vesicle Fusion Proteins

V-snare, T-snare, synaptotagmin, Rab3, Sec-1, and Munc 18

Ionotropic Receptor

Ligand-gated ion channel for fast signaling

Metabotropic Receptor

G protein-coupled receptor for slower signaling

Nicotinic Acetylcholine Receptors

Pentameric receptors at motor endplate for muscle contraction

Mini EPP

Spontaneous small depolarization due to release of single vesicle of NTs

Syncytium

Cells connected by gap junctions for coordinated contraction