CELL MEMBRANE & TRANSPORTATION TEST REVIEW Flashcards
Unit membrane theory
All membranes in all organisms are made the same
What does the cell membrane do
They are the gateway into the cell and must allow items such as nutrients into the cell without letting them escape. It also allows waste to leave the cells.
Parts of the fluid mosaic model (6):
- Phospholipid
- Glycolipid
- Glycocalyx
- Glycoprotein
- Peripheral protein
- Integral protein
- Cholesterol
Phospholipid
Phosphate group, glycerol, 2 fatty acids
Glycolipid
Carbohydrate chain attached to phospholipid
Glycocalyx
Carbohydrate chain that act as ID markers for cell
Glycoprotein
Carbohydrate chain attached to protein
Peripheral protein
Stabilizes and gives shape to membrane
Integral protein
Allows substances to move/exit membrane
Fluid portion of the FLUID MOSAIC MODEL
Double layer of phospholipid molecules that move like a light consistency of oil (fluid)
Mosaic portion of the FLUID MOSAIC MODEL
Proteins (wholly integral or partially peripherical embedded into phospholipid bilayer which forms the mosaic pattern on membrane
Glycocalyx that are attached to protein are called
Glycoprotein
Glycocalyx that are attached to phospholipid bilayers are called
Glycolipid
Channel protein
Allows molecule or ion cross the cell membrane based on size (glucose, ions, H2O)
Carrier protein
Interacts with specific molecule or ions to cross cell membrane (Na+K+ Pump)
What type of energy do carrier protein sometimes need
ATP
Receptor protein
Shaped in a way so that a specific molecule (specialized protein hormone) can bind to it (insulin, glucagon, growth hormone)
Cell recognition protein
Glycocalyx is different for each person. It indicates if cell is foreign to the body (organ transplants, blood transfusions)
Enzymatic protein
Speeds up a chemical reaction (lactase, sucrase, maltase)
Characteristics of molecules that can enter/exit membrane (4):
- Size. Smaller the molecule, the faster it can go through
- Shape. Awkward/rigid/irregular the molecular, the harder it is to pass through
- Charge. Ions with a charge have a hard time getting through the membrane
- Chemical composition of molecule. Non charged molecules
Examples of molecules that can easily pass through
Lipids such as steroids, phospholipids, neutral fats, fatty acids
Semipermeable membrane
Membrane that allows some participles to pass through by size
Selectively permeable membrane
Membrane that chooses what passes through and size is not a factor
How many ways of transportation is there to move molecules
2
Name of transportation 1 of molecules
Passive transport
Passive transport
No energy required but requires a concentration gradient
What is a concentration gradient
Region where there are more molecules on one side than the other
3 forms of passive transport
Diffusion, osmosis, facilitated diffusion/transport
What is diffusion
The spreading of something more widely
Examples of diffusion
Farts, diffusion of O2 or CO2 in lungs, perfume
Law of diffusion
Particles move from the area of high concentration to the area of low concentration until equally concentrated (equilibrium)
Is diffusion a fast or slow process, is energy required
Slow and no energy
How is the rate of diffusion affected
Through the concentration gradient between two regions, size and shape of molecules and temperature
Cytoplasmic streaming
Distribution of molecules that is used to speed up the flow of cytoplasm
3 ways of increasing the rate of diffusion:
- Increase temperature (increases kinetic energy of molecules)
- Increase concentration gradient
- Decrease size of diffusing molecules
Lipid soluble
Molecules like steroids and alcohol can diffuse directly across because the membrane itself is made of lipids
Water diffusing
Water diffuses readily across membrane through charged, protein lined pores in membrane
Osmosis
Movement of water from high concentration to low across semi or selectively permeable membrane until equal concentration is achieved. This is the diffusion of water
Why does the thistle tube rise
More H2O molecules outside solution than inside tube
Water is a universal ___
Universal solvent
Osmotic pressure
Pressure let out on the membrane due to the flow of water from area of higher concentration to lower
Concentration gradient
Region where 1 side has more molecules than the other side
How do you determine how high the osmotic pressure is
Greater concentration difference across membrane = greater osmotic pressure
Hydrostatic pressure
Pressure exerted on membrane due to weight of liquid pushing back on membrane
How is equilibrium achieved
Osmotic pressure = hydrostatic pressure (H2O exiting tube = H2O entering tube)
Facilitated transport function
Utilizes carrier or channel proteins in cell membrane to control passage of molecules in and out of cell
What molecules are facilitated transport specific to
Glucose or amino acids (Lipid insoluble molecules)
How do molecules in facilitated transport move
High to low concentration gradient
Do facilitated transport use energy
No ATP energy required
Tonicity
Strength of solution based on solute concentration
How is the concentration of a solution found
The amount of solute in a given volume of solution
Solution
Homogeneous mixture created when solutes dissolve in a solvent
Solvent
Fluid used to dissolve a solute
Solute
Substance that is being dissolved in a solvent (water)
Hypertonic solution
Solution concentration higher than that inside cell. Can’t cross membrane
Crenation
When animal cells (red blood cells) are placed in hypertonic solutions and shrivel up
Plasmolysis
When plant cells shrink when placed in hypertonic solutions due to osmosis. Central vacuole loses water, cell membrane shrinks and pulls away from cell wall
Hypotonic solution
Solution concentration lower and contains more water Cell will plump/swell
Hemolysis
When animal cells (red blood cells) are placed in hypotonic solution, they will swell and burst
What causes turgor pressure
Plant cells. As water enters, pressure builds up inside the cell and membrane
Name of transport 2 of molecules
Active transport
Active transport
Can go with or against a concentration gradient
Does active transport require energy
Yes, ATP
3 forms of active transport:
- Using carrier or channel proteins
- Endocytosis
i. Phagocytosis (cell eating)
ii. Pinocytosis (cell drinking)
iii. Receptor mediated endocytosis - Exocytosis
What does active transport require
Carrier and channel proteins
Direction of active transport
Can go again or with concentration gradient
Why is active transport vitally important to organisms
Moves Iodine from blood to thyroid
2 examples of active transport
Sodium transport out urine by kidney cells, and sodium|potassium pump in nerve/muscle cells moves the sodium from inside to the outside of cell
Process of Na|K pump:
- Carrier has shape that allows it to take up 3 Na ions
- ATP is split and phosphate group transferred to carrier
- Change in shape cause carrier to release 3 Na ions outside cell. New shape allows carrier to take up 2 K ions
- Phosphate group released from carrier
- Change in shape causes carrier to release K ions inside cell. New shape allows it to take up 3 Na ions again
Endocytosis
Takes in particles from the outside of cell. Cell membrane forms a vesicle or vacuole around substance to be taken in
Endocytosis requires energy?
Yes, ATP
3 forms of endocytosis:
- Phagocytosis
- Pinocytosis
- Receptor-mediated endocytosis
Phagocytosis
Cell eating. Vacuole forms around cell
Examples of phagocytosis
White blood cells engulfing debris like worn out RBC or bacteria. Amoebas ingesting food.
What microscope is used to observe phagocytosis
Compound
Pinocytosis
Cell drinking. Vesicles form around a liquid or around macromolecule (polypeptide).
Examples of pinocytosis
Lysosomes engulfing cell debris
What microscope is used to observe pinocytosis
Electron
Receptor-mediated endocytosis
Form of pinocytosis where molecules of substances like VITAMIN, PROTEIN HORMONE, OR LIPOPROTEIN can bind to receptor proteins on surface of cell membrane
What is the receptor-mediated endocytosis also referred to
Coated vesicle
Exocytosis
Reverse of endocytosis. Vacuole within cell fuses with cell membrane and the vacuole contents are deposited on the outside.
Importance of exocytosis
Secretion and excretion of cells
Function of vesicles in exocytosis
Vesicles produced by the golgi fuse with cell membrane as secretion occurs.
Extracellular fluid
Proteins released adhere to cell surface during EXOCYTOSIS and become incorporated to extracellular fluid
2 examples of exocytosis:
- Digestive enzymes produced by stomach and glands of small intestine.
- Hormones (insulin, glucagon) released by pancreatic cells when stimulated by nervous system
Difference between cell membrane and intra-cellular membrane
Intra-cellular membrane lacks glycocalyx (sugar chain)
Membranes that contain cholesterol and why
Animal cells. It is required for support + rigity of cell membrane
Function of cell membrane
Regulates what enters and leaves cell
Permeable
All molecules can pass through membrane
Non permeable
No molecule can pass through membrane
Semi permeable
(Nonliving membranes) only molecules of certain size pass through membrane
Selectively or differentially permeable
(Living membranes) molecules of certain size pass through membrane
Permeably of a cell membrane
Semi permeable. It is dependent on size and shape of molecule
3 main methods of which materials enter or leave cell
Diffusion, osmosis, active transport
Materials that can diffuse through membrane
Alcohol, gases
How does alcohol move through membrane
It is a lipid and is soluble through phospholipid bilayer
How does water move through membrane
Uses channel proteins to pass through membrane
ISO
Same
Importance of living cells in isotonic solution
H2O enter = H2oO leaving, and cell not damaged
HYPER
More than
Hypertonic solution
Solution with greater concentration of solute outside cell
Animal cell in hypertonic solution
Shrinks/shrivel
Plant cell in hypertonic solution
Plasmolysis (Cytoplasm sucked out of cell)
Term for red blood cell in hypertonic solution
Crenated
HYPO
Less than
Animal cell in hypotonic solution
Chubby
Plant cell in hypotonic solution
Turgor pressure (Chubby but won’t burst)
Lysis
Burst
Process of facilitated transport
Glucose or amino acid fit into specific carrier protein. As long as there is concentration gradient, glucose or amino acid will fit shape of carrier protein and move them through membrane (no ATP)
Highly specific carrier protein
Must be in order to allow correct molecule through membrane
Another name for facilitated transport
Facilitated diffusion
Another name for facilitated transport
Facilitated diffusion
Why is energy not needed for facilitated transport
Uses concentration gradient
Difference of active transport and facilitated transport
Active uses ATP to transport ions/molecules and facilitated uses concentration gradient + carrier protein to transport amino acid/glucose
Two things active transport needs for fuel
ATP and carrier proteins
Why do active transport have many mitochondria
Make ATP energy by cellular respiration used in active transport
Sodium potassium pump
Form of active transport used by all cells especially muscles and nerves
Endocytosis require energy regardless of concentration gradient, why
ATP is needed to create vesicle/vacuole that is used to transport
Phagocytosis and example
Vacuole formed at cell membrane to bring substances (cell) into cell mem. Requires ATP. WBC eating bacteria
Pinocytosis and example
Vesicle form around liquid or around small particles. Requires ATP. Lysosome eating cell debris
What happens to vesicles after contents incorporated into cell
Used for organelles inside
Process of receptor mediated endocytosis
It is a form of pinocytosis, but it uses receptor protein in a way that only specific molecules attach to receptor protein after attaching vesicle. Ex. Transporting vitamin, peptide, hormone, lipoprotein
Exocytosis process
Vesicle fuse with cell membrane as secretion occur during exocytosis. Membrane of vesicle become part of plasma membrane. Requires ATP for energy to transport and fuse
Diffusion direction, requirements, and example
High to low concentration, concentration gradient, O2 and alcohol
Facilitated transport direction, requirements, and example
High to low concentration, concentration gradient (specific to carrier protein)
Active transport using carrier protein direction, requirements, and example
Low to high concentration or high to low concentration, ATP energy, Na|K pump
Phagocytosis direction, requirements, and example
Low to high concentration or high to low concentration, Cell (vacuole), WBC eating bacteria cell
Pinocytosis direction, requirements, and example
Low to high concentration or high to low concentration, macromolecule (vesicle), lysosome eating cell debris
Receptor-mediated endocytosis direction, requirements, and example
Low to high concentration or high to low concentration, receptor protein, vitamin peptide hormone lipoprotein.
