Lab 3 Flashcards
what is a solute
a substance that devolves in a liquid
what is a solvent
a liquid that has dessolved or can dissolve one or more solutes
what is a solution
a liquid and its dissolved solutes
what does the plasma membrane allow to pass through the cell and how
it lets relatively small molecs to pass through them freely in both directions by diffusion and osmosis
what kind of transport processes in osmosis and diffusion
they are both passive transport processes
what is passive transport
transport occurs with out expenditure of energy
what is diffusion
the random movement of molecules of a substance from a area of high conc of that substance to an area of low conc of that substance..
what is a example of diffusion
this is the process by which gases are exchanged between cells and their environment, by which inorganic salts are taken up by plants and animal cells and by which ions are exchanges in kidney, muscle, and nerve cells in animals
how do prokaryotes devide
through binary fission
how does binary fission work
the cells single chromosomes (and plasmids) will replicate and then separate. the plasma membrane and cell wall grow inward, between the chromosomes, dividing the original cell into two identical daughter cells
how is the nucleus made up
nucleus contains DNA which is organized into chromosomes that are composed of DNA ad proteins (DNA + proteins is called chromatin) each chromosome has discrete units of hereditary information called genes. these are spicific nucleotide sequences of DNA thay code for particular charicteristics of an organism
what are chromosomes like in the nucleus
they are extended with their chromatin in long thing fibers
what do actively deviding cells undergo
cell cycle
what is the longest phase of a cell cycle
interphase
what happens at interphase
the cell groes and synthesizes new organelles and proteins in preperation for the next cell devision
what are the stages of cell cycle and mitosis
prophase
prometaphase
metaphase
anaphase
telophase
what happens in prophase
-replecated chromosomes (each made of two sister chromatids) condense and become visible under the microscope
-spindle microtubules begin to form and migrate to opposite ends of the cell
what happens in prometaphase
-nuclear envelope breaks down
-spindle microtubules grow and attach to the centromere regions of the replicated chromosome
what happens in metaphase
-spindle apparatus is completely formed
-replicated chromosomes are lined along the mid region of the cell also called the metaphase plate
what happens in anaphase
-centromeres of each replicated chromosome seperate
-single chromosomes are pulled by their centromeres to opposite poles
what happens in telophase in plants
-single chromosomes arrive at poles and begin to uncoil
-nuclear envolope begins to form around each group of chromosomes
-cytokinesis begins
what is the process of cytokinesis in plants
cell plate forms between the two nuclei and grows outward until it forms a complete cell wall that separates the two daughter cells
what is the process of cytokinesis in animals
cleavage furrow forms between the two nuclei and pinches the cell into two separate daughter cells
what are the stages in interphase
G1 stage: cell growth
S-stage: DNA synthesis
G2 stage: growth
what happens in G1 stage (cell growth)
new organelles and proteins are synthesized and the plasma membrane increases in size
what happens in S-stage (DNA synthesis)
each single chromosome produces an exact copy of itself by DNA replecation, forming a replicated chromosome (each copy is called a sister chromatid)
what happens in G2 stage (cell growth)
a second period of cell growth and final preparations for division
draw a chromosome drawing and chromosome diagram
refer to page 70 of lab manual
describe the the cells found in the meristematic region
they are usually small and thin walled and lack large vacuoles
in the meristematic region what should the approximate ratios of different cells be
30 prophase
20 metaphase
10 anaphase
7 telophase
100 interphase
how would you calculate the about of time that is spent in each stage
devide the number of cells in phase by the grand total number of cells counted and multiply the results by the munites it takes plant to complete cell cycle
how is a blastodisc produced
by a fertilized fish egg that has undergone many divisions
how are multicellular organisms though to have evolve from
through simpler unicellular organisms
how would the the evolutionary progression of a unicellular to multi cellular organism progressed
from unicellular to colonial forms
what is a colony
its comprised of individual cells or organisms that adhere to each other and may communicate with each other
how did the transition from unicellular to colonial forms then later to multicellular organisms occur
-individual unicellular organisms devided by mitosis (accompanied by cytokinesis), but instead of separating from each other the daughter cells remained stuck together
-repeated mitotic division resulted in larger colonies
-the final series of evolution of multicellularity was the transition from colonial to multicellular organism
how does multicellular compare to colonial multi cellular organisms
multicellular organisms are single organisms that have specilizeed cells that preform different functions
where are concentrations higher in cells or around
the concentration of solutes are often higher in the cell than outside
what is trigor pressure
in plant cells the water into the cell causes the central vacuole to increase in volume which pushes the plasma membrane out
what prevents the plasma membrane from bursting when water defuses into the cell
the elastic but ridged cell wall
what is plasmolysis
if water leaves the plant cell and the central vacuole decreases in volume as it looses water. as a result the plasma membrane pulls away from the cell wall
what does plasmolysis result in
the wilting in plant tissue
what does the term wilted apply to
plant tissue not the individual cells
plants that are wilted are…
plasmolysed
what is the pyrenoid
contained withing the choloroplast and responsible for the synthesis of starch from sugars produced by photosynthesis
what us a chlamydomonas
it is a motile unicellular alga
what things can you identify in a chlmydomonas
flagella
cell wall
plasma mem
nucleus
pyrenoid
cup chaped cloroplact
eye spot
what is a gonium
a simple colonial alga
how are multi cellular organisms held together
in a simple flat or curved plate by a gelatinous matrix
how many flagella does each cell of the colony have
two
how many cells make up a colony
the number is genetically predetermined and varies with species
how do adjacent colony cells communicate with each other
via slender cytoplasmic bridges
what does slender cytoplasmic bridges allow for
communication between adjacent cells allows for the coordination of flagellar movement which propels the colony towards the light
while each individual cell of the colony is in communication with the others there is no…
division of labour among cells
what things should you be able to identify in a gonium colony
cell
gelatinous matrix
eyespot
flagella (if seen)
how is is belived that the gonium arose from
from the chlamydomonas type cells which divided repetitively (by mitosis) and adhered to each other via a gelatinous matrix
what is a eudorina
a colonial alga
how can you think of eudorina structure compared to gonium
if you can imagine that the edges of a gonium colony joined up so that the colony is now a ball of cells, with flagella directed outward, you would have an alga simular to eudorina
how would you examine eudorina under a microscope
turn the light on to low magnification and watch the rolling motion
what structures should you be able to spot on a eudorina cell
cell
gelatinous matrix
what is a volvox
a multicellular alga
how would you examine a slide for volvox
-examine under 4x objective w out a cover slip
-find large, hollow spherical orgainism which swims with rolling motion
-keep slide stationary with ligh sourse on and watch them move into field of view
-then apply cover slip and look under 40x
what are the small green spheres you may see in some volvox
they are daughter organisms which is a result of asexual reproduction
what are the two types of of cells volvox has
somatic cells and reproductive cells
what do somatic cells in the volvox do
they make up the wall of the organism
