Chap 3: cells Flashcards
(53 cards)
What is cell theory
Cell is the smallest structural and functional living unit
- all living things are composed of unicellular or multicellular
- cell is basic unit of life
- cells arise from preexisting cells
Epithelial, Fibroblasts and erthrocytes cells
cells that connect body parts, form linings or transport gases
skeletal muscle and smooth muscle cells
Cells that move organs and body parts
fat cell
cells that stores nutrients
macrophage
cells that fight disease
nerve cell
cell that gathers information and controls body functions
sperm
cell of reproduction
nerve cells consist of what
cell body, nucleolus, dendrites, axon, nucleus, axon hillock
muscle cells consist of what
nuclei, perimysium, straitions, skeletal muscle fiber
what are the 3 basic parts of human cells?
plasma membrane: flexible outer boundary, selectively permeable
cytoplasm: intercellular fluid containing organelles
nucleus: control center
cell membrane and its parts
75% phospholipids (lipid bilayer)
- phosphate heads: polar and hydrophilic
- fatty acid tails: nonpolar and hydrophobic
5% glycolipids
- lipids with polar sugar groups on outer membrane surface
20% cholesterol
- increases membrane stability and fluidity
what are the 2 types of membrane proteins
integral proteins
- firmly inserted into membrane and most are transmembrane
- functions as transport proteins (channels + carriers), enzymes/receptors
peripheral proteins
- loosely attached to integral proteins
- functions as enzymes, motor proteins, cell to cell links. provide support on intercellular surface and form part of glycocalyx
what are the 6 functions of membrane proteins
- transport channels
- receptors for signal transduction
- attachment to cytoskeleton and extra cellular matrix (maintain cell shape)
- enzymatic activity
- intracellular joining: CAM - cell adhesion molecule
- cell to cell recognition - identification tag
what are the 3 membrane junctions
- tight junction: impermeable
- prevents fluid and most molecules from moving between cells - desmosome - rivets that anchor cells together (velcro)
- gap junction: communicating, small pores b/w cells that allow small molecules to pass
what are the 2 types of membrane transport
plasma membranes are selectively permeable
- passive transport: no energy required, substance moves down concentration gradient
- active transport: energy required, substance moves against concentration gradient (ATP)
what determines passive permeability
- lipid solubility of substance
- channels of appropriate size
- carrier proteins
- concentration gradient
- charge of substance
what are the 3 passive processes
- simple diffusion
- facilitated diffusion
- carrier mediated
- channel mediated - osmosis
what is simple diffusion
no polar lipid soluble and HYDROPHOBIC diffuses directly through phospholipid bilayer (O2/CO2/lipid soluble vitamins)
what is facilitated diffusion
utilizes carrier proteins or channel proteins that exhibits specificity, saturable (rate determined by number of carriers/channels), can be regulated in terms of quantity and activity
what are carrier proteins and channel proteins?
carrier proteins: binding of substrate causes shape change in carrier
channel proteins: aqueous channel formed by transmembrane proteins, leakage channels, gated channels
what is osmosis?
movement of solvent across a selectively permeable membrane
water diffuses through plasma membranes through lipid bilayer or through water channels (aquaporins)
what happens when membrane is permeable to both solute and water
volume remains unchanged and solute moves from left to right (low to greater osmolarity)
what happens when membrane is permeable to water but impermeable to solute
both solutions have identical similarity but volume of solution is greater in the right because water is free to move
what is tonicity and it’s 3 types?
tonicity: ability of solution to cause a cell to shrink/swell
- isotonic: solution with same solute concentration as that of cytosol (ideal)
- hypertonic: solution having GREATER SOLUTE concentration than cytosol (lose water via osmosis and shrink - more solute)
- hypotonic: a solution having LESSER SOLUTE concentration than that of the cytosol (gain of water via osmosis and lyse - low solute)