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Membrane lipids composition
- 75% phospholipids (bilayer)
- 5 % glycolipids (carbs)
- 20 % cholesterol
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Semipermeable
regulates what comes in and out of cell
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plasma membrane function
seperates intracellular fluid (ICF) from extracellular fluid (ECF)
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Cytoplasm
intracellular fluid containing organelles
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plasma membrane
"cell membrane" flexible outer boundary
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Golgi Apparatus
stacked and flattened membranous sacs
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Rough ER has what well developed?
golgi apparatus
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Intermediate filaments (variety of proteins)
tough, insoluble, protein fibers constructed like woven ropes
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Microfilaments (actin)
strands made of sperical protein sub units called actins
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Microtubules (tubulin)
hollow tubes of sperical protein subunits called tubulins
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Cytoskeleton
elaborate series of rods throughout cytosol
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3 types of cytoskeleton
1. microtubules (tubulin) 2. microfilaments (actin) 3. intermediate filaments (variety of proteins)
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Lysomes
sperical membranous bags containig digestive enzymes. digest ingested bacteria, viruses, and toxins
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Sarcoplasmic reticulum
stores calcium when muscle cells at rest
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Smooth ER in skeletal and cardiac muscle
storage and release of calcium
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Smooth ER in intestinal cells
absorbtion, synthesis, and transport of fats
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Smooth ER in liver
breakdown of glycogen and detoxification
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Rough ER
external ribosomes. synthesizes membrane
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Endoplasmic Reticulum (ER)
interconnected tubes and parallel membranes (smooth ER rough ER)
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Ribosomes
hook amino acids together to form peptide bond
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Mitochondria
needs oxygen. "soupy material". provide cells ATP. contain own DNA
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Thickness of the plasma membrane
10 nanometers
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Cytoplasmic organelles that are nonmembranous
cytoskeleton and ribosomes
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cytoplasmic organelles taht are membranous
mitochondria, endoplasmic reticulum, golgi apparatus
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cytoplasmic organelles
metabolic machinery of cell
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cytoplasm
located between plasma membrane and nucleus
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Outside of plasma membrane, the charge is always what
0
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Resting membrane potential (RMP)
voltage measured in resting state in all cells
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Membrane Potential
seperation of oppositely charged particles across a membrane creates
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Excitable Cells
neurons and muscle cells. AP. brief. reversal so positive.
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What 4 processes are powered by ATP
1. primary active transport 2. exocytosis 3. phagocytosis 4. pinocytosis
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What does the cytoskeleton do?
helps movement of vesicles to surface by use of ATP
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Exocytosis
Secretory cells. product for use outside of cells. release a lot in pulses
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Pinocytosis
fluid phase endocytosis. deform the plasma membrane.
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what are the 2 kinds of phagocytosis
macrophages and some white blood cells
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Phagocytosis
pseudopods engulf solids and bring them into cells interior
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Endocytosis
draws material into cells
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How many flagella are present at once
1
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How many cilia are present at once
6-10
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flagella
motile extensions on surfaces of certain cells. contain microtubules and motor molecules.
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Cilia
motile extensions on surface of certain cells. move substance across surface. contain microtubules and motor molecules
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Motor molecules
little cellular muscles. powered by ATP
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importance of intermediate filaments
support cell shape
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importance of microfilaments
contraction
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Importance of microtubules
shape and movement
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Dynein
protein motor with cilia and flagella
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Hair cells
sensitive cells inside of ear (helps sound travel)
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Integral Proteins
firmly inserted into the membrane (transmembrane)
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Peripheral Proteins
include filament on intracellular sufrace and glycoproteins on extra-cellular surface
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Function of membrane proteins
1. transport 2. receptors 3. intercellular joining 4. cell-cell recognition 5. enzymatic activity
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Cause of autoimmune diseases
cell recognition not correct and cause cells to attack own tissue
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3 types of membrane junctions
1. tight junction 2. desmosome 3. gap junction
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tight junctions
prevent molecules from passing through intercellular space. looks like stitchnig
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Desmosomes
bind cells together. causes a very strong attachment
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gap junctions
very imporatnt for communication. pass from one cell to the next.
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passive processes (diffusion based)
no energy required. happens by itself. does not reach equilibrium
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active processes
energy (ATP) required. works uphill against gradient concentration
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concentration gradient
more atoms on one side than the other side
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simple diffusion
nonpolar lipid- soluble (hydrophobic) substances diffuse directly through phospholipid bilayers
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leakage channels
always open
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gated channels
(majority) "has a lid on it" chemically or electronically opened
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two types of channel proteins
1. leakage channels 2. gated channels
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2 types of facilitated diffusion
1. carrier proteins 2. channel proteins
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carrier proteins
transmembrane integral proteins transport specific polar proteins. saturable
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Channel proteins
channels formed by protein transports water and ions. hard to saturate
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osmosis
movement of water across a selectively permeable membrane
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aquaporins (AQPs)
water diffuses through plasma membrane through these water channels
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molecules move individually
active transport
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vesicular transport
'bundles' move together
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two types of active processes
1. active transport 2. vesicular transport
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active transport
require carrier protein and pump. moves against concentration gradient
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two types of active transport
1. primary active transport 2. secondary active transport
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primary active transport
atp causes shape change so ions are "pumped"
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how much energy is used during sodium- potassium atpase?
3%- 10%
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phagocytosis
pseudopods engulf solids and bringthem into cells interior
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oncogenes
onco= cancer. cell cycle promoters. "unspecialized"
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stem cell therapy
use blood from umbilical cord
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stem cells
unspecialized cells. ex. bone marrow
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what two items are hard to repair?
nerve cells and muscle
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are epithealial tissues hard to repair?
no
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increase in cell number means
growth
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cytokinesis
division of cytoplasm by cleavage furrow
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mitosis
nuclear cell division event
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mitotic (M) phase
needed for growth and tissue repair. does not occur in most mature cells
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G2
preparation for division
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S
DNA copied. chromosomes total 46 (doubled)= 92 total
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G0
gap phase where cells quit dividing
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G1
80% pf time. prepare to reproduce. vigarous growth and metabolism
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Four sub divisions of interphase
G1 G0 G2 S
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Interphase
period from cell formation to cell division
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cell cycle
life and times of a cell
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nuclear envelope
double membrane barrier containing pores
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red blood cells are ____
anucleate
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nucleus
main battery that directs cellular activity
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Microvilli
fingerlike extensions of plasma membrane. increase SA for absorbtion
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