106 - ____ = ____/____ = _______

Biology 332
Spring 1998

Exam I

Name_________________

Why Study Plants?
Think about a frog and how it is dependent upon plants. Then, think about how your life as a human is dependent upon plants...directly or indirectly. Below, list as many different ways plants impact humans which are not the same ways that plants impact a frog. A list might be the best way to approach this question. Don't write books...it's only worth 8 points!

Wood for Homes
Fossil Fuels for Heat, Electricity
Fibers for Clothes
Paper for Writing
Resins for Paint, Varnish
Latex for Condoms, Gloves, Tires
Decoration for Landscaping etc.
Jobs for Employment

Note: You cannot use oxygen, ozone, food, etc.!

Cells, Cell Cycle and Cell Division 10 points.

Name the cell type that goes through the cell cycle continuously.meristematic
Name an isodiametric cell type that is alive but does not cycle.parenchyma
In what part (be specific) is the non-cycling cell stopped?G1 or G2 of interphase
Name the longest phase of the cell cycle.interphase
In what part of the cell cycle is transcription unlikely?mitosis
In what specific part of the cell cycle is replication likely?S of interphase
Name a functional cell type that does not cycle because it is dead.sclerenchyma


Cell Structure and Function: Borders
In the space below, briefly list the structure and critical function(s) of the three layers of the border of a "typical" plant cell. 13 points

Border Layer (3)Structural Information (5)Critical Functions (5)
middle lamellapectinglues cells together
cell wallcellulose
hemicellulose
(protein)
prevents explosion in hypotonic solutions
becomes plastic to allow cell growth
cell membranephospholipids
proteins
regulates import
and export

Cell Structure and Function: Chloroplast
In the space below, describe the parts of a chloroplast and their basic function(s). Be as specific as you can. Your essay should be as complete as possible! Maybe a small, well-labeled diagram will help? Thinking about the origin of the chloroplast might help too. Don't forget the function(s)! 12 points.

outer membraneeukaryotic vesicle which took-in endosymbiont
transports nuclear genetic expression materials into chloroplast
inner membraneprokaryotic cell membrane
imports nuclear genetic expression materials into chloroplast
thylakoidETS for light reactions of PS
stromaenzymes for Calvin Cycle
70s ribosomestranslation of chloroplast-encoded genes
nucleoidtranscription of chloroplast-encoded genes


Respiration 15 points.
Give the overall reaction (in one step) for respiration of glucose:

CH2O + O2 ----> CO2 + H2O + energy

In your reaction above, circle the components involved directly in glycolysis. CH2O, energy

In your reaction above, put a square around the components involved in the Kreb's cycle. CO2, energy

In your reaction above, put a triangle around the components involved with electron transport. H2O, O2, energy!

Specifically where in the cell does glycolysis take place? cytosol

Specifically where does the Kreb's cycle take place? mitochondrial matrix

Specifically where is the electron transport system located? mitochondrial cristae (mesosomes)

Photosynthesis 10 points.
Give the overall (one-step) reaction for photosynthesis:

CO2 + H2O light
--------------->
chlorophyll
O2 + CH2O

In your reaction above, circle the components involved in the light reactions.
H2O, light, chlorophyll, O2

Now, think about the connection between the light and light-independent ("dark") reactions.
Which of these: 3 points.
can occur without the other?   light       "dark"       both       neither
involves an electron transport system?   light       "dark"       both       neither
Which of these is enzyme catalyzed?   light       "dark"       both       neither

In your project yesterday, the leaf discs would not refloat unless bicarbonate was provided in the buffer. Explain this observation, given that the project was directly measuring the rate of photolysis (2 H2O ----> O2 + 4H++ 4e-) rather than any other part of photosynthesis. 5 points.

If a C-3 plant were exposed to radioactive carbon dioxide (*CO2) in light and immediately examined, in what chemical would the radioactivity be first found? 1 point

water       carbon dioxide       carbohydrate       starch       oxygen

If a C-3 plant were exposed to heavy oxygen (H2*O) in light and immediately examined, in what chemical would the heavy isotope be first found?

water       carbon dioxide       carbohydrate       starch       oxygen


Compare the three kinds of photosynthesis: 14 points
C-3 PlantC-4 PlantCAM Plant
Name an example plant or the biome (habitat where it is found abundantly bean
temperate zone
corn
tropical grasslands
sedum
desert
Is the Calvin cycle operating in daytime? Yes       No Yes       No Yes       No
Is photorespiration a problem? Yes       No Yes       No Yes       No
Does it involve two different cells? Yes       No Yes       No Yes       No
Is the plant doing anything
photosynthetic at night?
Yes       No Yes       No Yes       No
Is PEP carboxylase an important
photosynthetic enzye?
Yes       No Yes       No Yes       No
This is most competitive where light is
abundant but water is severely limited.
Yes       No Yes       No Yes       No
This is most competitive where light is
abundant and water is moderate.
Yes       No Yes       No Yes       No
This is most competitive where light is
not optimal and water is plentiful.
Yes       No Yes       No Yes       No

Scientist Yet? 14 points.
In the remaining space, use all seven steps of the scientific method in sequence to determine whether the cells of a fern gametophyte produce starch as a product of photosynthesis. Name the steps and what you would do/see in each one!
Name of StepWhat you Do
ObservationNotice gametophyte is green and has chloroplasts, use metric system as needed
QuestionBe curious, could PS in chloroplasts generate starch?
HypothesisChloroplasts do not carry out photosynthesis and do not produce starch
Prediction
  • If hypothesis is true
  • then chloroplast should have not have black specks
  • when illuminated plant is stained with iodine.
ExperimentControl: stain gametophyte held in darkness for several days
Treatment: stain gametophyte held in light for several days.
AnalysisCompare control with treatment
use statistics and allow 5% error!
specks in lighted gametophyte's chloroplasts, not in control
DecisionReject hypothesis, or Cannot reject hypothesis


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