biology lab exam 2

why was the spinach dipped in boiling water

the losen the cell wall so the ethanol can be abosrbed better

after dipping the spinach in boiling water what did the spinach go into and why?

the spinach went into 95% ethanol which allowed all of the different pigments to sepearate and come out of the spinach

after adding the ethanol to the spinach what solvent was added and why?

after the ethanol, the pertroleum ether was added to the mixture to seprate the lower yellow carotene ether layer from the green chlorophll layer

what solvent was added to separate the chlorophylls

92% ethanol was added to separate chlorophyll a and chlorophyll b — the top layer was the ether chlorophyll a layer and then the bottom layer is the ether chlorophyll layer.

why are different solvents used in this the photosynthesis lab

each of the pigments dissolve in different solvent so in order to divide and seprate them all out, different solvents are used

what are the rules with the spectra and the different pigment used in photosynthesis 1

the pigments never change their wavelength, meaning only the amount of light absorbed by pigments changes between different concentrations

where does photosynthesis take place

in the thylakoid membrane inside the chloroplast

what is oxidation

this is the removal of electrons

what is the reduction of a substance

it is the additon of electrons

what happens to the NADP+ at the end of transport chain

NADP+ gets reduced to NADPH

What does DPIP do

it is an artifical electron acceptor that starts off dark blue (oxidized), can take the place at the end of a transport chain and then use these electrons to become reduced. when reduced it turns clear and this transformation is used to identify the rate of water oxidation because the two things are porportional

how do the photosystems gain energy in the electron transport chain

photosystems use pigments to draw in light energy to push the electrons up the transport chain

why is a buffer used in the photosynthesis lab 2

a buffer is used with the introduction of DPIP and chloroplasts in order to maintain the PH so it doesnt alter the experiment

why was bifulfate added to the blank solution in photosynthesis 2 lab

bisulfate was added to the blank was to reduce DPIP levels so there wasnt a blue color when taking the absorbance

how does adding more chlorophyll effect the absorbance and rate or water oxidation

adding more cholorphyll or pigments allowd for the slope to be higher and the water oxidation to be higher

during photosynthesis 2 lab what does it mean when there is no slope of a spectra

this means that there is no concentation of chlorophyll

for photosynthesis 2 lab what was the negative control group in the testing afterwards =

the negative control group was when we tested the oxidation rate when there was no late and no heat. this was used to confirm that DPIP was not going to reduce spontaniously

no light, no heat test

there was no change in color, which proves that the reduction of DPIP doesn’t happen from heat alone.

light + no heat

this test isolates the variable of light, during this the absorbance drops steadily, and the

in photosynthesis lab 2, what is happending when the absorbance drops steadily on the graph

this happens when more chloroplasts are added because the more chloroplast the allows the DPIP to reduce (become clear) at a faster rate, which is represented by the fall in absorbance.

how does heat effect the rate of oxidation of water in photosynthesis 2

heat alters the rate pf photosynthesis independantly from water but it is very unreliable

how much chlorella is used in photosythesis lab 3

8 ml in the oxygen probe

what are we measuring is lab photosynthesis 3

we are measuring how the distance from light (PFR) effects the rate of oxygen concentration being created (photosynthesis )

where is the area of large PFR

180 PFR is located closest to the light

how does PFR effect the about of oxygen dissolved?

at a higher PFR (closest to the light) there is more oxygen being dissolved

why can there be negative values of dissolved oxygen in photosynthesis lab 3

there can be negative values when there is not light present because the chlorella is undergoing repiration and using the oxygen when there is no light to replace it, therefore it negative

Describe linear growth

steady and predidiable, increasing by a fixed amount over equal intervals of time

describe exponential growth

fixed proportion of individuals that double every time

logistic growth

the most relalistic graph that takes into account the real world limitations

what are the different parts of the logistic graphs

lag phase- beignins where the births > deaths

Log phase- population is apporoahcing deaths

stationary phase - where the births=deaths, no more can be produced with the amount og resources have

what is the carrying capacity

the limit to which a species can reproduce without limitation of resources