week 4, feb 21st - 25th Flashcards
Describe the plasma cell membrane
Called fluid mosaic layer
Fluid = molecules move laterally (sideways)
Mosaic = collage, pathwork of proteins
What is the plasma cell membrane mostly composed of
Phospholipid bilayer
Describe the phospholipid bilayer and other elements of the plasma membrane
Integral proteins (transmembrane) used for transport
Peripheral proteins are not embedded or for transport
Cholesterol influences fluidity of membrane
Glycoproteins and glycolipids are for cell recognition
What happens inside the cell in relation to the plasma membrane and its components
Integral protein and cholesterol and the peripheral proteins work together
What happens outside the cell in relation to the plasma membrane and its components
The glycoproteins and glycolipids are formed
What type of permeability does the plasma membrane have
Semi permeable
Describe what can go through the plasma membrane
Fat soluble, non polar, hydrophobic molecules go through phospholipid bilayer 
Polar, hydrophilic monomers or ions go through integral proteins
What cannot go through plasma membrane
Polymers
They need to be wrapped in vesicle that will fuse to plasma membrane, requires ATP
What are the 2 types of transport
Passive transport and active transport
Describe passive transport
High concentration to low (with concentration gradient)
No ATP needed
Reaches equilibrium (equal concentrations on both sides of cell membrane)
Name the 3 types of passive transport
Simple diffusion
Carrier-facilitated diffusion
Osmosis
Describe active transport
Low concentration to high (against gradient)
Needs ATP
Leads to different concentrations across membrane
Name the 3 types of active transport
Endocytosis (eg phagocytosis)
Exocytosis (protein exportation)
Pumps
Describe simple diffusion
For fat soluble molecules (small gases like O2 & CO2, alcohol ester pesticides)
Non polar & hydrophobic
Goes through phospholipid bilayer
Describe carrier facilitated diffusion
Polar & hydrophilic monomers (glucose) or ions (gated channels)
Goes through a specific integral protein
Glucose goes to receptor, protein changes shape and releases glucose to area of low glucose
Describe osmosis
Movement of water from an area of high concentration to low concentration across a semi permeable membrane
What is hypotonic
High H2O less solutes
What is hypertonic
Low H2O high solutes
Describe a plant cell in hypotonic, isotonic and hypertonic solutions
Hypotonic = osmotic pressure pushes inwards, turgor pressure is the resistance of cell wall, cell is turgid :) Isotonic = flaccid :\ Hypertonic = plasma membrane collapses, plasmolysis :( (death)
Describe an animal cell in hypotonic, isotonic and hypertonic solutions
Hypotonic = bursts, hemolysis :( (death) Isotonic = :) equilibrium Hypertonic = shrivels up :\
Describe exocytosis
Protein secretion/exportation
Happens in golgi, protein transported in a secretory vesicle and is exported
Plant cells secrete more cell wall material by exocytosis
Name the 2 types of endocytosis
Phagocytosis and pinocytosis
Describe phagocytosis
Cellular eating
Formation of pseudopods surrounding food or germ, engulfs food or germ into a food vacuole, lysosomes fuse with food vacuole = intracellular digestion
Describe pinocytosis
Cellular drinking
Droplets of liquid with polymers enter groove/infold, forms vesicle containing droplets (nutrients), lysosome fuses with vesicle, hydrolysis of polymers
Happens for tapeworms, sperm cells and oocytes (fed by pinocytosis)
