Lab 4 Flashcards
selectively permeable
some substances can pass through while some can’t
diffusion
tendency for solute to spread from an area of high solute concentration to an area of low solute concentration as a result of constant random movements
is diffusion active or passive?
passive, does not require energy
how is equilibrium achieved?
solute evenly distributed across solvent, no net movement
solute
substance dissolved in a liquids
solvent
liquid the solute is dissolved in
what organelle controls diffusion in a cell?
cell’s plasma membrane
osmosis
movement of water from an area of high water concentration to an area of low water concentration across a selectively permeable membrane
what is the rate of osmosis dependent on?
temperature, solute concentration
cell membrane
selectively permeable membrane that separates interior of cell from external environment
nucleus
organelle containing DNA, chromosomes, and genetic info
Nuclear Envelope/Membrane
semipermeable membrane separating interior of nucleus from the cell’s cytoplasm, has nuclear pores
nucleolus
region in nucleus where RNA is manufactured and ribosomal subunits assembled
mitochondria
organelle that breaks down carbs to produce energy in the form of ATP via cellular respiration
rough endoplasmic reticulum
where proteins are synthesized, folded, packaged, and processed, contains ribosomes
smooth endoplasmic reticulum
where lipids such as phospholipids are synthesized and processed
ribosomes
macromolecular machines that manufacture proteins by transcription and translation
golgi apparatus
shipping centre of cell, packages molecules into vesicles, modifies lipids and proteins
lysosomes
recycling center of cell, has digestive enzymes that break down cell parts and substances
centrioles
may help organize microtubule assembly, a pair is found within the centrosome in animal cells
chloroplast
uses solar energy to synthesize carbs via photosynthesis
cell wall
durable outer layer that gives structural support to plant cells
central vacuole
storage compartments for water in plant cells
how many layers thick is the onion epidermis?
one layer
where is the nucleus usually located in plant cells?
between the plasma membrane and vacuole membrane
what microscope is necessary to see membranes?
transmission electron microscope
how thick are elodea leaf cells?
two cells thick
why can you not see vacuole of elodea leaf on compound microscope?
it is enclosed by a membrane as thing as plasma membrane (10nm) and is not pigmented by chlorophyll
Magnification formula
M = Si/So
What is general shape of chloroplasts?
oblong
cytoplasmic streaming/cyclosis
organelles move along cytoskeleton inside cells
Why do onion epidermis cells lack chlorophyll?
onion epidermis do not carry out photosynthesis and instead serve as protection
Amyloplasts
storage compartments for starch
what are three microscopic structural differenves between plant and animal cells?
plant cells are rigid,boxy, have chloroplasts, and a large central vacuole whereas animal cells lack both organelles and lack structure
what does it mean when a cell is turgid?
central vacuole is filled, causing pressure within the cell because cell membrane is snug against the cell wall, causing cell rigidity
what is plasmolysis?
Contraction of the cell contents
due to the loss of water
the process of water leaving a cell due to the solution outside of the cell being hypertonic compared to inside, leading to the central vacuole collapsing and plasma membrane shrinking away from the cell wall
why does cell wall not shrink during plasmolysis?
cell wall is rigid and maintains its structure
what can you do to make wilted veggies turgid again?
add lettuce to water, a hypotonic solution relative to the inside of cell, so that water moves across semipermeable plasma membrane of plant cells through osmosis
what happens to plant cells in hypotonic solution?
water enters cell which has a lower concentration of water compared to outside, leading to turgor pressure developing
what happens to plant cells in hypertonic solution?
water leaves cell which has a higher concentration of water compared to outside, leading to plant cells plasmolyzing and shrinking
what happens to plant cells in isotonic solution?
nothing, no net movement, stays the same due to equilibrium already established
hypertonic solution
solutions with higher conc. of solute compared to solution inside the cell
turgor pressure
outward pressure exerted by fluid contents of a living plant cell
isotonic solution
solutions with same conc. of solute compared to solution inside cell
hypotonic solution
solutions with lower conc. of solute compared to solution inside cell
osmotic pressure
Measure of the
tendency of water to move across a
differentially permeable membrane;
visible as an increase in liquid on the
side of the membrane with higher solute
concentration
