Download Lab Quiz 4 Study Guide Know the Domain, Kingdom and cellular

Lab Quiz 4 Study Guide
1. Know the Domain, Kingdom and cellular characteristics (structure/organelles) of:
a. Amoeba (including how they eat and move) see my ppt notes
i. Domain: Eukarya; Kingdom: Protista; a single-celled protozoan
(animal-like protist)
ii. Cellular structure/organelles: remember no cell wall; there is a cell
membrane, cytoplasm (fluid part called cytosol), nucleus, contractile
vacuole, and food vacuoles; the cytoplasm is the outer and gelatinous
ectoplasm and the inner, more fluid endoplasm.
iii. Pseudopods: false-feet; temporary cytoplasmic extrusions that are used
for eating (via phagocytosis) and moving.
iv. Phagocytosis: cellular eating via pseudopods
v. Amoeboid movement: crawling-like type of movement via protrusion of
cytoplasm involving formation of pseudopodia; the cytoplasm slides and
forms a pseudopodium in front to move the cell forward.
b. Elodea (including plasmodesmata and cytoplasmic streaming)
i. Domain: Eukarya; Kingdom: Plantae; a green photosynthetic plant.
ii. Cellular organelles: cell wall, cell membrane, cytoplasm, nucleus,
central vacuole, and chloroplast (other organelles and structures we
can’t see with the light microscope).
iii. Plasmodesmata: membrane-lined channels between the cell walls of
adjacent plant cells; strands of cytoplasm pass through these channels
and connect the living contents of adjacent cell; important for
communication between plant cells.
iv. Cytoplasmic streaming: the circular flow of a fluid layer of cytoplasm
within a plant cell (one hypothesis is that myosin motors attached to
organelles in the fluid cytoplasm drives the streaming by interacting
with actin filaments).
v. Function of cytoplasmic streaming? Speeds distribution of materials
(water, ions, and other small molecules) within cells; also cytoplasmic
streaming enhances the transport of water and solutes between cells via
plasmodesmata.
2. What organelles and other structures are not found in animal cells? Cell wall,
chloroplast, central vacuole, and plasmodesmata.
3. Diffusion: The net movement of particles down a concentration gradient (from where
they are more concentrated to where they are less concentrated).
4. Osmosis: the diffusion of water across a selectively permeable membrane.
5. Selectively permeable: the plasma membrane and other non-biological membranes
(dialysis tubing) are selective as to what particles/molecules/substance can pass
across them. The plasma membrane (a phospholipid bilayer) is permeable to nonpolar molecules and small molecules like water, carbon dioxide and oxygen; but it is
impermeable to water-soluble molecules like sugars, amino acids and ions (they cross
the membrane via transport proteins). Dialysis tubing is a membrane that is selective
based on size of its pores. If the molecules are smaller than the pores, they can pass,
but if they larger they will not pass.
6. Compared to another solution:
a. Isotonic: having the same solute concentration
b. Hypotonic: having a lower solute concentration
c. Hypertonic: having a higher solute concentration than another solution
7. A 20% saline solution contains:
a. how much water? 80% water (80 mL out of 100 mL)
b. how much saline? 20% salt (20 mL out of 100 mL)
8. Assume the interior of an onion cell is 96% water. What direction does water
diffuse when an onion epithelial layer is placed in the following:
a. 100% distilled water? Water concentration is highest outside the cell, so
water will diffuse…
b. 20% saline (20% salt particles and 80% water molecules)? Water
concentration is highest _____________ the cell, so…
9. In which environment are plants the happiest (hypertonic, hypotonic or isotonic)?
10. When placed in a hypotonic solution (100% distilled water) why don’t plant cells
burst?
a. When water moves into plant cells by osmosis the cell expands. But the cell
walls are strong and can’t expand much. So the pressure rises inside the cell –
it becomes tightly filled and it reaches the greatest tugor pressure. This makes
the cells rigid and helps support the plant upright (I’m so happy!)
b. To sum it up, the cell wall prevents excess intake of water into the cell. It exerts
osmotic pressure that opposes water movement into the plant cell and prevents
it from bursting.
11. What is stock solution composed of? Starch, sodium chloride (salt), and glucose
12. Know what each chemical is used to test for the presence of:
a. Iodine: starch
b. Silver nitrate: chloride ions -so salt
c. Benedicts solution: simple sugars – glucose
13. Explain what should have happened in our dialysis experiment and why? (Review
your data in tables 2 and 3 and your activity E questions; note that whatever doesn’t
pass across the dialysis tubing/membrane down its concentration gradient into the
beaker water is because it is too large to pass through the pores in the membrane.
This membrane is being selective based on size of the particle.)
14. Define Brownian movement. The random movement of molecules in a solution due
to being struck by other molecules (i.e. water molecules).
15. What caused the carmine particles to move on your slide you prepared? Carmine
is a fine powder that forms a suspension of tiny particles when mixed with water
(visible under the light microscope). In this suspension we observed the random
movement of carmine particles. (Brownian motion). The carmine particles are moving
due to the collisions of fast moving, invisible water molecules with the visible particles.
a. What is heat? Heat is a form of energy.