lab 4 Flashcards

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1
Q

what is photosynthesis?

A

allows certain cells to take inorganic molecules from the environment and build them into enormous macromolecules. concerts light energy into chemical energy

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2
Q

what is cellular respiration?

A

converts the macromolecular raw materials into chemical energy which can be utilized by the cell

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3
Q

where does 90 percent of photosynthesis activity occur?

A

in algae present in the surface water of the ocean

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4
Q

which substances absorb visible light?

A

pigments, and they are found in the chloroplasts for plants

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5
Q

how can we determine the fact that chloroplasts contain multiple pigments?

A

through paper chromatography (separate components)

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6
Q

which pigment is responsible for the green colour in plants/ major pigment?

A

Chlorophyll a

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7
Q

which pigments are considered to be accessory?

A

Chlorophyll b, xanthophyll and carotenoids

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8
Q

Which pigment is this?

A

Chlorophyll b

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9
Q

Which pigment is this?

A

Xanthophyll

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10
Q

Which pigment is this?

A

Beta-carotene

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11
Q

what groups are considered to be polar?

A

COH, O, CO, OCH3

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12
Q

how can the relative polarity of a pigment be determined?

A

by counting the polar groups on each molecule

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13
Q

what provides strong evidence that chlorophylls are necessary pigments for photosynthesis?

A

the graph for optimal oxygen released (rate of photosynthesis) vs wavelength coincides with the graph of MOST absorption of light depending on wavelength of that light for each pigment

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14
Q

true or false, cell respiration is considered to be combustion?

A

true

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15
Q

what is the electron transport chain for cellular respiration?

A

Within the inner membrane of the mitochondria, the hydrogens and electrons released in the breakdown of glucose to CO2 and water are passed along by a sequence of redox reactions. With each passage of electrons, energy is released and coupled to the synthesis of ATP. Molecular oxygen is the final acceptor of the hydrogen atoms, resulting in the formation of water molecules

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16
Q

what are the two types of tests done to evaluate cell respiration?

A

qualitative and quantitative

17
Q

which cell respiration test is qualitative and which is quantitative?

A

qualitative: tetrazolium test: only tells us if respiration is happening or not

quantitative: oxygen sensor test: tells us how much cell respiration is happening through the measurement of oxygen consumption

18
Q

what is the tetrazolium test?

A

used to determine seed viability. Tetrazolium salts are reduced (producing a pink precipitate) during the process of respiration and thereby can indicate the percentage of viable seeds within a given lot

19
Q

why does a seed going through cellular respiration indicate that its viable?

A

Germination and seedling emergence is a highly metabolic event and relies on the breakdown of starch stored in the seed for use in respiration. Therefore, a viable seed can be observed as a seed which is undergoing respiration.

20
Q

how do u find the seed viability of a lot?

A

For example, if 100 seeds are tested and 83 present the pink precipitate upon tetrazolium testing, then seed viability of that lot will be indicated as 83%.

21
Q

what is the oxygen sensor test?

A

allows us to see how much cellular respiration is happening in a seed lot. the oxygen sensor that we put the peas in allows us to measure how much oxygen they are consuming. oxygen sensor uses gas volume to determine this.

22
Q

how is the oxygen measured in the oxygen sensor test?

A

in ppm

23
Q

why do we need a control oxygen sensor for the oxygen sensor test? what do we do with it?

A

As a control, this inclusion is necessary because gas volume may be affected by factors other than respiration. Recalling the equation PV = nRT, it can be readily understood that external factors such as temperature or barometric pressure could affect the gas volume within the sensor. The changes in gas volume which occurs in the sensor containing non-viable seeds will be subtracted from the gas volume changes observed in the viable or respiring seeds

24
Q

what does the geranium leaf experiment allow us to see?

A

illustrates the requirement for light and carbon dioxide for photosynthesis

25
Q

explain the geranium leaf experiment?

A

Three geranium plants were placed under different conditions for 4 days:

1)Plant #1 was kept under normal light + CO2 normal (atmospheric) conditions.Demo was with no iodine

2)Plant #2 was kept in the presence of light in an air-tight jar containing KOH toabsorb carbon dioxide. CO2 deprived for one week.

3) Plant #3 was kept in the dark, deprived of light but normal CO2

26
Q

in the geranium leaf experiment, how do we determine which leaves are going through photosynthesis under the conditions that they’ve been put through?

A

The ability of the plants to photosynthesize and thus produce and store starch was determined by removing photosynthetic pigments by boiling the leaves in ethanol, then adding iodine.

A dark blue/dark brown colour indicates the presence of starch. A light brown colour indicates the absence of starch.

27
Q

what test are we conducting in order to see which components of plant pigments are the most polar?

A

paper chromatography (separates components of pigments based on their polarity)

28
Q

Why is starch being evaluated as a measure of photosynthesis? Can O2 production (evolution) be used as a measure of photosynthesis as well? Brielfy explain.

A

Starch is the storage form of glucose (as the product of photosynthesis) measured qualitatively (or quantitatively) using iodine. Oxygen is also a product of photosynthesis and its production could be measured with oxygen sensors to reflect the rate of photosynthesis.

However, because oxygen is also being consumed by the plant it may be difficult to measure an accurate rate of oxygen production.

29
Q

Given the structures of the plant pigments on the following page, determine the relative polarities of the pigments. During the chromatographic separation, which pigment should migrate the greatest distance? Which should migrate the least distance?

A

relative polarities from least to most polar:
beta-carotene, xanthophyll, chlorophyll a, chlorophyll b

greatest distance migrated: beta-carotene

smallest distance migrated: chlorophyll b

30
Q

what’s the formula for photosynthesis?

A

6H20 + 6CO2= C6H12O6+ 6O2

31
Q

what’s the formula for cell respiration?

A

C6H12O6+ 6O2= 6H20+ 6H20

32
Q

How do we find the rate of oxygen consumption and what is the units of it?

A

The rate of O2 consumption is the slope of this graph, and the units are in ppm O2/viable pea/min

33
Q

Fill out this table. What do we use these values for?

A

We use these values in order to plug them into the the graph to find the rate of oxygen consumption

34
Q

what are the units we’re looking for in the oxygen consumption rate?

A

ppm O2 consumed/hour per seed

35
Q

what plant are we taking pigments from for the chromatography test?

A

spinach

36
Q

between a pink seed and a non-pink seed, which one is considered to be viable during the tetrazolium test?

A

pink one