Chapter 3 Flashcards
What is cytology?
The scientific study of cells
What is cell theory?
All organisms are composed of cells, cells are the simplest unit of life, cells only come from preexisting cells, cells all have similarities
What does a squamous cell look like?
Thin, flat, and scaly
What do cuboidal cells look like?
Square
What do columnar cells look like?
Taller than wide
What do stellate cells look like?
Star-like
What do fusiform cells look like?
Thick in the middle, tapered toward ends (kinda like a diamond)
3 basic components of a cell?
Plasma membrane, cytoplasm, and nucleus
What does the plasma membrane do?
Define cell boundaries, govern interactions with cells, and control passage of materials in and out of the cell
How is the cell membrane made?
Phospholipids w/ hydrophilic heads and hydrophobic tails
What else composes the cell membrane, besides phospholipids?
Cholesterol, glycolipids, and membrane proteins
What are peripheral proteins?
Proteins that adhere to one face of the membrane but don’t penetrate it
What do receptors do?
Bind chemical signals
What are second messenger systems?
A first messenger binds to a surface receptor, triggering a change within cell to produce second messenger in cytoplasm
What do enzymes do in the membrane?
Catalyze reactions like digesting molecules and producing second messengers
What are channel proteins?
Proteins that allow hydrophilic solutes and water to pass through the membrane
What do ligand-gated channel proteins respond to?
Chemical messengers
What do voltage-gated channel proteins respond to?
Charge changes
What do mechanically-gated channel proteins respond to?
Physical stress on cell
What are membrane protein carriers?
A transmembrane protein which binds solutes and transfers them across the membrane
What are cell-identity markers?
Glycoproteins acting as ID tags to distinguish self from foreign
What do cell-adhesion molecules do?
Mechanically link cell to extracellular material or another cell
What is the glycocalyx?
Fuzzy coat external to plasma membrane. Unique in everybody but identical twins
Functions of the glycocalyx?
Protection, immunity to infection, defense against cancer, transplant compatibility, cell adhesion, fertilization, embryonic development
What are microvilli?
Extensions of the membrane which increase a cell’s surface area
What are cilia?
Hairlike processes which monitor nearby conditions
What do motile cilia do?
They sweep material across a surface in one direction, specifically they mostly move mucus or dust
What is cystic fibrosis?
A recessive disease where cells can’t create the saline layer for mucus to float on top of, so tracts get plugged
What is the only flagellum in humans?
The tail of a sperm cell
What membrane transportation mechanisms do not require ATP?
Filtration, diffusion, osmosis
Which membrane transportation mechanisms require ATP?
Active transport and vesicular transport
What are carrier-mediated mechanisms?
Using a membrane protein to transport a substance across a membrane
What is filtration?
Particles are driven through membrane by physical pressure
What is simple diffusion?
Net movement of particles from place of high concentration to place of lower concentration
What factors affect simple diffusion rates?
Temperature, molecular weight, steepness of gradient, membrane surface area, membrane permeability
What is osmosis?
Net flow of water through a selectively permeable membrane
What are aquaporins?
Channel proteins specialized for water passage for osmosis, speeds up process
What is osmolarity?
The concentration of a solution, # of solutes per liter
What is tonicity?
Ability of a surrounding solution to affect fluid volume and pressure in a cell
What is a hypotonic solution?
The cell absorbs water and swells, ECF has lower concentration of nonpermeating solutes
What is a hypertonic solution?
Cell loses water and shrivels, ECF has higher concentration of nonpermeating solutes
What is an isotonic solution?
Causes no change in cell volume, concentrations of nonpermeating solutes in and outside cell are the same
What does it mean for carrier-mediated transport to be saturated?
All carriers are occupied
What are the types of carriers for transport?
Uniport, symport, and antiport
How do uniports move solutes?
It carries only one type
How do symports move solutes?
It carries 2 or more solutes simultaneously in the same direction
How do antiports move solutes?
It carries 2 or more solutes simultaneously in opposite directions
What are the methods of carrier-mediated transport?
Facilitated diffusion, primary active transport, and secondary active transport
What is facilitated diffusion?
A method of carrier-mediated transport which moves a solute down its’ gradient. Does not use ATP
What is primary active transport?
A method of carrier-mediated transport which moves solute through a membrane up the gradient. Uses ATP
What is the sodium-potassium pump?
A pump that consumes one ATP to exchange 3 Na+ out for two K+ in, necessary because they constantly leak
What does the sodium-potassium pump do?
Maintains steep gradient for transport, regulates solute concentration, maintains membrane potential, produces heat
What is secondary active transport?
Carrier moves solute through membrane but only uses ATP indirectly
What is vesicular transport?
Moves large particles, fluid droplets, or numerous molecules at once through the membrane in bubble-like enclosures called vesicles
What is endocytosis?
Vesicular processes that bring material into cell
What is phagocytosis?
A form of endocytosis, “cell-eating”, engulfing large particles
What is pinocytosis?
A form of endocytosis, “cell drinking”, taking in droplets of ECF containing molecules useful in the cell
What is receptor-mediated endocytosis?
Particles bind to specific receptors on plasma membrane
What is transcytosis?
Transport of material across the cell by capturing it on one side and releasing it on the other
What is exocytosis?
Secreting material, replacing plasma membrane removed by endocytosis
What is the cytoskeleton?
A network of protein filaments and cylinders that determines cell shape, supports structure, organizes cell contents, directs movement of materials within cell, contributes to movement of the cell as a whole.
What is the cytoskeleton composed of?
Microfilaments, intermediate filaments, and microtubules
What do microfilaments do?
Form terminal web
What do intermediate filaments do?
Give cell shape, resist stress
What do microtubules do?
Maintain cell shape, hold organelles, act as railroad tracks for walking motor proteins, make axonemes of cilia and flagella, form mitotic spindle
What are the membranous organelles?
Nucleus, mitrochondria, lysosomes, peroxisomes, endoplasmic reticulum, and Golgi complex
What are the nonmembranous organelles?
Ribosomes, centrosomes, centrioles, basal bodies
What does the nucleus do?
Genetic control center, direct protein synthesis, shelter DNA
What does the nuclear envelope do?
Protect the nucleus, regulate molecular traffic through
What is the endoplasmic reticulum?
System of channels (cisternae) enclosed by membrane
What does rough ER do?
Synthesizes proteins
What does smooth ER do?
Synthesizes steroids and other lipids
What do ribosomes do?
Read genetic messages from mRNA and assemble amino acids into the specified proteins. Protein synthesis
What does the Golgi complex do?
Synthesizes carbohydrates and finishes protein synthesis
What do lysosomes do?
Hydrolytic digestion, autophagy (digests cell’s extra organelles), and autolysis (digests entire extra cell)
What are ribosomes made of?
Granules of protein and RNA
What are lysosomes made of?
Package of enzymes bound by a membrane
What do peroxisomes do?
Use molecular oxygen to oxidize organic molecules. Neutralize free radicals, detoxify drugs
What do mitochondria do?
Synthesize ATP
What do centrioles do?
Form basal bodies of cilia and flagella, which anchor them to cell membrane
