unit 2 test review Flashcards
why must cells remain small
to maintain a large surface area to volume ratio
Surface area must be large enough to all the cell to:
obtain resources
eliminate waste
acquire/dissipate thermal energy
exchange chemicals/energy with environment
why should cells have a large SA:V ratio
allows increased rates of chemical exchange between cell and environment
light microscope characteristics
Visible light passes through specimen
Refracts light so specimen is magnified
Magnify up to 1000X
Specimen can be alive/moving
Color
Can’t see organelles other than nucleus
electron microscope charactersitics
Focuses a beam of electrons through/onto specimen
Magnify up to 1,000,000 times
Specimen non-living and in vacuum
Can see organelles
Track the journey of a protein/polypeptide from the endoplasmic reticulum to how it would exit a cell.
DNA is in chromatin in nucleus
Then go to rough ER
Translate message into amino acid sequence
Then to golgi with transport proteins by vesicles
Goes thru cis face side of golgi
Then leaves through the trans face
Leaves on a transport vesicle to then go to membrane
Then exocytosis out of the cell
animal cells
Only membrane
Lysosomes
Microvilli
Plant cells:
Central vacuole
Chloroplasts
Cell wall+membrane
Prokaryote
No nucleus (Nucleoid-DNA concentration)
DNA in a nucleoid
Cytoplasm/Cytosol
No organelles other than ribosomes
Small size
Primitive
i.e. bacteria
eukaryote
Has nucleus and nuclear envelope
Cytoplasm/Cytosol
Membrane-bound organelles with specialized structure/function
Much larger in size
More complex
i.e. plant/animal cell
where are chloroplasts found? function? what do they do? what does it contain and what is its purpose?
Only in plants
Function: site of photosynthesis
converts light energy into chemical energy ie. carbohydrates
Contains chlorophyll (green pigment) for capturing sunlight energy
compartmentalization
the way organelles present in the eukaryotic cells live and work in separate areas within the cell in order to perform their specific functions more efficiently
how do membranes achieve compartmentalization
Internal membranes create a greater SA:V ratio
Nucleus, mitochondria, ER, golgi, chloroplasts all have internal membrane folds that help compartmetalize
why is compartmentalization important
More efficiency in cell’s functions
components of membrane
phospholipids bilayer
proteins
cholesterol
phospholipid bilayer properties
cellular barrier/border (selectively permeable)
Impermeable to polar molecules
Amphipathic
proteins determine
membrane’s specific function
proteins 7 functions
Transport
Enzymatic activity
Signal transduction
Cell-cell recognition
Intercellular joining
Attachment to the cytoskeleton and extracellular matrix
Peripheral proteins and integral proteins
cholesterol purpose in membrane
acts as a fluidity buffer - resisting changes in fluidity as temperature changes
fluid mosaic model shows
Membrane fluidity
Cholesterol in animal cell membrane
Movement of phospholipids
Proteins floating throughout phospholipid bilayer
what membrane has no kinks
saturated fatty acid tails - viscious
what membrane has kinks
unsaturated fatty acid tails - fluid
6 functions of membrane
Transport
Enzymatic activity
Signal transduction
Cell-cell recognition
Intercelluar joining
Attachment to cytoskeleton + extracellular matrix
channel proteins
embedded in the cell membrane & have a pore for materials to cross
carrier proteins
can change shape to move material from one side of the membrane to the other
amphipathic meaning
a molecule that has a hydrophilic and a hydrophobic region
how does the amphipathic features of the phospholipid bilayer affect its function
Only some molecules are able to go through the membrane because it is nonpolar or polar
CAN pass through lipid bilayer
fats & other lipids, hydrocarbons, CO2, Oxygen, hydrophobic molecules
CANNOT pass through lipid bilayer
polar molecules (H2O), ions (charged)-salts, ammonia, large molecules (starches, proteins)
diffusion
High to low concentration
Passive transport
No energy is needed
Solute moves DOWN concentration gradient until reached equilibrium (then no net movement)
Facilitated diffusion
High to low concentration
Passive transport
No energy needed
Needs proteins to move
Channel proteins: embedded in cell membrane and have pore fro materials to cross (like water slide)
Carrier proteins: can change shape to move material from one side of membrane to other
Hypertonic
more solute, less water (when comparing the solution to the cell)
If the solution is hypertonic
Solute will move inside of cell
Water will move out of cell
hypotonic
less solute, more water (when comparing the solution to the cell)
If the solution is hypotonic
Solute will move out of cell
Water will move inside of cell
isotonic
equal solute, equal water (when comparing the solution to the cell)
If solution is istonic
Solute and water will both move equally until equilibrium (not really because they were already equal so they don’t need to reach equilibrium)
NO NET MOVEMENT
hypertonic plant and animal cells
Animal cell: shrivels
Plant cell: plasmolysis
hypotonic plant and animal cells
Animal cell: burst (lysed)
Plant cell: turgid (normal)
isotonic plant and animal cells
Animal cell: normal
Plant cell: flaccid
Understand how molecules move via active transport.
(Membrane potential also called voltage)
Moves substances AGAINST concentration gradient
Needs energy (ATP)
Low to high
Carrier proteins
sodium potassium pump
Na+ ions: high OUT and low IN
K+ ions: low OUT and high IN
what influences the direction that ions move in the membrane
electrochemical gradient
Describe how a membrane potential is created across a membrane. What is this also called?
Created by differences in distribution of positive and negative ions
Also called voltage
steps of sodium potassium pump
- cytoplasmic Na binds to sodium-potassium pump
- Na binding stimulates phosphorylation by ATP
- phosphorylation causes the protein to change its shape, Na is expelled to the outside
- Potassium binds on the extracellular side and triggers release of the phosphate group
- loss of the phosphate restores the protein’s original shape
- potassium is released and the cycle repeats
pinocytosis
molecules are taken up when extracellular fluid is “gulped” into tiny vesicles
Phagocytosis
cellular digestion, lysosomes fuse with food vacuoles
receptor-mediated endocytosis
binding of ligands to receptors triggers vesicle formation
Understand how the molarity of the unknown solutions (colored) was determined and what it meant when bags/cells gained or lost mass. Explain how the molarity of the veggie was calculated.
Bags gained mass when they were hypertonic to solution
Bags lost mass when they were hypotonic to solution
Water potential (and graph) on lab explained:
Molarity in reference of concentrations of solute
Water potential of carrot equal to water potential of solution
That one point tells us the molarity of that solute in that solution
water potential calculation
Water potential = Solute potential + Pressure potential
Solute potential
-ICPT (cannot be positive because of the negative sign in front of the I)
Ionization number
Concentration
Pressure
Temperature
