Lab 3

Question 1

what is a solute

Answer 1

a substance that devolves in a liquid

Question 2

what is a solvent

Answer 2

a liquid that has dessolved or can dissolve one or more solutes

Question 3

what is a solution

Answer 3

a liquid and its dissolved solutes

Question 4

what does the plasma membrane allow to pass through the cell and how

Answer 4

it lets relatively small molecs to pass through them freely in both directions by diffusion and osmosis

Question 5

what kind of transport processes in osmosis and diffusion

Answer 5

they are both passive transport processes

Question 6

what is passive transport

Answer 6

transport occurs with out expenditure of energy

Question 7

what is diffusion

Answer 7

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..

Question 8

what is a example of diffusion

Answer 8

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

Question 9

how do prokaryotes devide

Answer 9

through binary fission

Question 10

how does binary fission work

Answer 10

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

Question 11

how is the nucleus made up

Answer 11

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

Question 12

what are chromosomes like in the nucleus

Answer 12

they are extended with their chromatin in long thing fibers

Question 13

what do actively deviding cells undergo

Answer 13

cell cycle

Question 14

what is the longest phase of a cell cycle

Answer 14

interphase

Question 15

what happens at interphase

Answer 15

the cell groes and synthesizes new organelles and proteins in preperation for the next cell devision

Question 16

what are the stages of cell cycle and mitosis

Answer 16

prophase
prometaphase
metaphase
anaphase
telophase

Question 17

what happens in prophase

Answer 17

-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

Question 18

what happens in prometaphase

Answer 18

-nuclear envelope breaks down
-spindle microtubules grow and attach to the centromere regions of the replicated chromosome

Question 19

what happens in metaphase

Answer 19

-spindle apparatus is completely formed
-replicated chromosomes are lined along the mid region of the cell also called the metaphase plate

Question 20

what happens in anaphase

Answer 20

-centromeres of each replicated chromosome seperate
-single chromosomes are pulled by their centromeres to opposite poles

Question 21

what happens in telophase in plants

Answer 21

-single chromosomes arrive at poles and begin to uncoil
-nuclear envolope begins to form around each group of chromosomes
-cytokinesis begins

Question 22

what is the process of cytokinesis in plants

Answer 22

cell plate forms between the two nuclei and grows outward until it forms a complete cell wall that separates the two daughter cells

Question 23

what is the process of cytokinesis in animals

Answer 23

cleavage furrow forms between the two nuclei and pinches the cell into two separate daughter cells

Question 24

what are the stages in interphase

Answer 24

G1 stage: cell growth
S-stage: DNA synthesis
G2 stage: growth

Question 25

what happens in G1 stage (cell growth)

Answer 25

new organelles and proteins are synthesized and the plasma membrane increases in size

Question 26

what happens in S-stage (DNA synthesis)

Answer 26

each single chromosome produces an exact copy of itself by DNA replecation, forming a replicated chromosome (each copy is called a sister chromatid)

Question 27

what happens in G2 stage (cell growth)

Answer 27

a second period of cell growth and final preparations for division

Question 28

draw a chromosome drawing and chromosome diagram

Answer 28

refer to page 70 of lab manual

Question 29

describe the the cells found in the meristematic region

Answer 29

they are usually small and thin walled and lack large vacuoles

Question 30

in the meristematic region what should the approximate ratios of different cells be

Answer 30

30 prophase 20 metaphase 10 anaphase 7 telophase 100 interphase

Question 31

how would you calculate the about of time that is spent in each stage

Answer 31

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

Question 32

how is a blastodisc produced

Answer 32

by a fertilized fish egg that has undergone many divisions

Question 33

how are multicellular organisms though to have evolve from

Answer 33

through simpler unicellular organisms

Question 34

how would the the evolutionary progression of a unicellular to multi cellular organism progressed

Answer 34

from unicellular to colonial forms

Question 35

what is a colony

Answer 35

its comprised of individual cells or organisms that adhere to each other and may communicate with each other

Question 36

how did the transition from unicellular to colonial forms then later to multicellular organisms occur

Answer 36

-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

Question 37

how does multicellular compare to colonial multi cellular organisms

Answer 37

multicellular organisms are single organisms that have specilizeed cells that preform different functions

Question 38

where are concentrations higher in cells or around

Answer 38

the concentration of solutes are often higher in the cell than outside

Question 39

what is trigor pressure

Answer 39

in plant cells the water into the cell causes the central vacuole to increase in volume which pushes the plasma membrane out

Question 40

what prevents the plasma membrane from bursting when water defuses into the cell

Answer 40

the elastic but ridged cell wall

Question 41

what is plasmolysis

Answer 41

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

Question 42

what does plasmolysis result in

Answer 42

the wilting in plant tissue

Question 43

what does the term wilted apply to

Answer 43

plant tissue not the individual cells

Question 44

plants that are wilted are...

Answer 44

plasmolysed

Question 45

what is the pyrenoid

Answer 45

contained withing the choloroplast and responsible for the synthesis of starch from sugars produced by photosynthesis

Question 46

what us a chlamydomonas

Answer 46

it is a motile unicellular alga

Question 47

what things can you identify in a chlmydomonas

Answer 47

flagella cell wall plasma mem nucleus pyrenoid cup chaped cloroplact eye spot

Question 48

what is a gonium

Answer 48

a simple colonial alga

Question 49

how are multi cellular organisms held together

Answer 49

in a simple flat or curved plate by a gelatinous matrix

Question 50

how many flagella does each cell of the colony have

Answer 50

two

Question 51

how many cells make up a colony

Answer 51

the number is genetically predetermined and varies with species

Question 52

how do adjacent colony cells communicate with each other

Answer 52

via slender cytoplasmic bridges

Question 53

what does slender cytoplasmic bridges allow for

Answer 53

communication between adjacent cells allows for the coordination of flagellar movement which propels the colony towards the light

Question 54

while each individual cell of the colony is in communication with the others there is no...

Answer 54

division of labour among cells

Question 55

what things should you be able to identify in a gonium colony

Answer 55

cell gelatinous matrix eyespot flagella (if seen)

Question 56

how is is belived that the gonium arose from

Answer 56

from the chlamydomonas type cells which divided repetitively (by mitosis) and adhered to each other via a gelatinous matrix

Question 57

what is a eudorina

Answer 57

a colonial alga

Question 58

how can you think of eudorina structure compared to gonium

Answer 58

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

Question 59

how would you examine eudorina under a microscope

Answer 59

turn the light on to low magnification and watch the rolling motion

Question 60

what structures should you be able to spot on a eudorina cell

Answer 60

cell gelatinous matrix

Question 61

what is a volvox

Answer 61

a multicellular alga

Question 62

how would you examine a slide for volvox

Answer 62

-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

Question 63

what are the small green spheres you may see in some volvox

Answer 63

they are daughter organisms which is a result of asexual reproduction

Question 64

what are the two types of of cells volvox has

Answer 64

somatic cells and reproductive cells

Question 65

what do somatic cells in the volvox do

Answer 65

they make up the wall of the organism