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78 Cards in this Set

  • Front
  • Back
The cellular level of organization
basic, living, structural and functional unit of the body
The cellular level of organization is responsible for
-compartmentalization of chemical reactions within specialized structures
-regulate inflow and outflow of materials
-use genetic material to direct cell activities
study of cellular structure
cell physiology
study of cellular function
plasma membrane
cell membrane
genetic material of cell
everything between the membrain and the nucleus
what is found between the membrane and nucleus?
intracellular fluid
subcellular structures with specific functions
plasma membrane
held together by hydrogen bonds
lipid bilayer of the cell membrane
2 back to back layers of 3 types of lipid molecules.
cholesterol and glycolipids scattered among a double row of phospholipid molecules
-compromises 75% of lipids
phospholipid bilayer
2 parallel layers of molecules
Describe the molecules in a phospholipid bilayer
2 parts
-polar parts(heads)are hydophilic and face on both surfaces a watery environment
-non polar parts (tails) are hydrophobic and line up next to each other in the interior
sugar fat molecules
Glycolipids within the cell membrane
-compromises 5% of the lipids of the cell membrane
-carbohydrate groups form a polar head only on the side of the membrane facing the extracellular fluid
stiff steroid ring inside of every cell wall
cholesterol within the cell membrane
-compromises 20% of cell membrane lipids
-interspersed among the other lipids in both layers
-stiff steroid rings and hydrocarbon tail are nonpolar and hide in the middle of the cell membrane
centrosome plays a role in
formation of cilia and flagella
2 types of membrane proteins
integral, and peripheal proteins
Describe peripheal proteins
attached to either inner or outer surface of cell membrane and are easily removed from it
Formation of channel
passageway to allow specific substances to pass through
transporter proteins
bind a specific substance, change their shape and move it across membrane
Receptor proteins
cellular recognition site bind to substance
Cell identity marker
allow cells to recognize other similar cells
-anchor proteins in cell membrane or to other cells
-allow cell movement
-cell shape and structure
Act as enzyme
speed up reactions
Transmembrane proteins
protein extends completely across
What do glycoproteins do for the cell?
gives cell uniqueness, protects it from being digested creates a stickiness to hold it to other cells or so it can hold a fluid layer creating a slippery surface
Membranes are what type of structures?
fluid structures(oil layers)
- self sealing if punctured with a needle
Membrane fluidity
a compromise of fluids --membrane molecules can rotate and move freely
-need to stay in one half of lipid bilayer
-fluidity is reduced by presence of cholesterol
Why does membranes need to stay in one half of the lipid bilayer?
Its difficult for hydrophilic parts to pass through hydrophobic core of bilipid layer.
Membrane Fluidity
Describe fluidity is reduced by presence of cholesterol
increases stiffness of membrane it forms hydrogen bonds with neighboring phospholipid heads
Lipid bilayer
- permeable to nonpolar, uncharged molecules--oxygen, co2, steroids
- permeable to water which flows through gaps that form in hydrophobic core of membrane as phospholipids move about
Transmembrane proteins act as specific channels.
small and medium polar and charged particles
Macromolecules unable to pass through the membrane.
vesicular transport
active transport
uses atp to drive substances against their concentration gradients. (walking up a hill)
passive transport
moves substances down their concentration gradient with only their kinetic energy. (jumping on a sled)
Vesicular transport
moves material across membranes in small vesicles either by exocytosis or endocytosis. (active)
random mixing of particles in a solution as a result of the particles kinetic energy
-more molecules move away from an area of high concentration to an area of low concentration
-when the molecules are evenly distributed, equilibrium has been reached
5 things about diffusion
-the greater the difference in concentration between the 2 sides of the membrane, the faster the rate of diffusion
-the higher the temp, the faster the rate of diffusion
- the larger the size of the diffusing substance, the slower the rate of diffusion
-an increase in surface area increases the rate of diffusion
- increases diffusion distance, slows rate of diffusion
Affects of tonicity on rbcs in lab
normally the osmotic pressure of the inside of the cell is equal to the fluid outside the cell
-cell volume remains constant (solution is isotonic
Effects of fluids on rbcs in lab.
-water enters the cell faster than it leaves
-water enters and leaves the cell in equal amounts
-water leaves the cell
Isotonic solution
- water concentration the same inside and outside of cell results in no net movement of water across cell membrane
Hypotonic solution
higher concentration of water outside of cell results in hemolysis
Hypertonic solution
lower concentration of water outside of cell causes crenation
Diffusion through the lipid bilayer.
-important for absorption of nutrients--excretion of wastes
-nonpolar, hydrophobic molecules(oxygen, carbon dioxide, nitrogen, fatty acids, steroids, small alcohols, ammonia and fat-soluble vitamins a/e/d/k)
Facilitated diffusion
-substance binds to specific transporter protein
-transporter protein conformational change moves substance across cell membrane
Facilitated diffusion occurs down concentration gradient only
if no concentration difference exists, no net movement across membrane occurs
Rate of movement in facilitated diffusion depends upon
-steepness of concentration gradient
-number of transporter proteins(transport maximum)
net movement of water through an area of high water concentration(low particle concentration) to an area of low water concentration.(high particle concentration)
When does osmosis occur?
only occurs if membrane is permeable to water but not to certain solutes
-diffusion through lipid bilayer
-aquaporins (transmembrane proteins) that function as water channels
Osmosis of water through a membrane
-pure water on the left side and a membrane impermeable to the solute found on the right side
-net movement of water is from left to right, until hydrostatic pressure (osmotic pressure) starts to push water back to the left
Active transport
movement of polar or charged substances against their concentration gradient.
Active transport requires
-energy from hydrolosis of atp (primary active transport)
-energy stored in an ionic concentration gradient (secondary active transport)
Active transport exhibits
transport maximums and saturations
Function -digest foreign substances
-autophangy(autophagosome forms)
(recycles own organelles)
(lysosomal damage after death)
-part of normal metabolic breakdown of amino acids and fatty acids
-oxides toxic substances such as alcohol and formaldehyde
-contains catalase which decomposes h2o2
-generation of ATP
-powerhouse of cell
-cell support and shape
-organization of chemical reactions
-cell and organelle movement
Cell organelles
-nonmembranous organelles lack membranes and are indirect contact with cytoplasm
- membranous organelles surrounded by one or two lipid bilayer membranes
Primary and secondary active transport are
atp driven
Function of nucleus
46 human dna molecules or chromosomes
the sites of protein synthesis
Golgi complex
processes and packages proteins produced by rough er
Vesicular transport of particles
bringing something into cell
-receptor mediated endocytosis=selective input
release something from cell
-vesicles form inside cell, fuse to cell membrane
-release their contents(digestive enzymes, hormones, neurotransmitters or waste products)
-replace cell membrane lost by endocytosis
cell eating by macrophages and wbcs
-particle binds to receptor protein
-whole bacteria or viruses are engulfed and later digested
cell drinking
-no receptor proteins
Receptor-mediated endocytosis=selective input
mechanism by which hiv virus enters cells
Endoplasmic reticulum
network of membranes forming flattened sacs or tubles called cisterns
-half of membranous surfaces within cytoplasm
Rough er
-continuous with nuclear envelope and covered with attached ribosomes
-synthesizes, processes and packages proteins for export
-free ribosomes synthesize proteins for local use
Smooth er
no attached ribosomes
-synthesizes phopholipids, steroids and fats
-detoxifies harmful substances(alcohol)
Gradients across the plasma membrane
substances move
down their concentration gradient and towards the oppositely charged area
Gradients across the plasma membrane
membranes can maintain a difference in charged ions between
inside and outside of membrane
Gradients across the plasma membrane
membrane can maintain difference in
concentration of a substance inside versus outside of the membrane(concentration gradient)