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ECOL 182 (Spring) Intoductory Biology - Sample Questions for Exam Three

Here are some questions - they highlight how I write and how you should look at the material I presented in lecture. I will post some information about content in a separate page - the answer to the question is BOLD. I also give a short 'main-point' following each question.

1. Of the following prokaryotic groups, which DO NOT produce oxygen from reactions associated with photosynthesis?
   1. purple bacteria and cyanobacteria
   2. gram positive bacteria and green sulfur bacteria
   3. cyanobacteria and gram positive bacteria
   4. all of the above
   5. none of the above

Notice that I always use five options - often including 'none of the above'. Try not to let that throw you, but use it to help you with your certainty in your answer. The point on this question is that CYANOBACTERIA are the only prokaryotic group that does produce oxygen - it's one of the points that we wanted you to remember from the first lecture.

1. Chloroplasts of photosynthetic protests
   1. Have well defined nuclear regions
   2. Gave rise to mitochondria
   3. Are all descended from a once free-living cyanobacterium
   4. All have exactly two surrounding membranes
   5. Are all descended from a once free-living red alga

Recall that we discussed this in the context of a phylogeny - placing both mitochondria and chloroplasts on a tree containing prokaryotes and eukaryotes.

1. The universal design of the photosynthetic structure includes which of the following?
1. antenna / reaction center complex
2. chlorophyll based light harvesting pigments
3. heterodimeric protein core reaction center
4. all of the above
5. none of the above

This was a big point I made in the lecture - which also hinted at some evolutionary implications (e.g., a universal design, but important variation in the parts - how many times did photosynthesis evolve?).

1. When sugars produced in the chloroplast are removed to the cytosol by means of a photophate translocator, which event occurs?
1. CO2 fixation rate by RUBISCO is maintained or increases
2. Phloem cells unload sugars into vessel elements to make up for reductions in transpiration
3. Chloroplasts fill with starch and the Calvin Cycle does not operate
4. Both b and c
5. None of the above

This is an example of that 'sink' limitation of photosynthesis that I described several times in the first lecture (remember - photosynthesis is controlled at many levels - here at the interface between chloroplasts and the whole-cell). By moving sugars away from photosynthesis, there is not a 'feed-back' inhibition of photosynthesis - realize that this question is a little complex, because the easier version is likely on the exam.

1. Which of the following confer advantages to growing on the land
   1. Stomata, gametangia and cuticles
   2. Sporophytes, desmostomata and paraenchyma
   3. Pigments, thick cell walls, and stomata
   4. Both 2 and 3
   5. Both 1 and 3

Desmostomata are a synapomorphy of embryophytes (remember?), which disqualifies the second answer. The rest are from the part of the lecture where I told you that invading the land was like invading the air and most of these prevent dessication.

1. Derived non-seed plants (such as club mosses) and seed plants (such as conifers) share which following synapomorphy?
1. Vessel elements
2. Sexual reproduction
3. Tracheids
4. A dominant sporophyte generation
5. 1 and 4

This one is a little tricky (and it will not be on the exam) - but it highlights how you should know how groups are connected in our tree of life - what shared, derived characteristics do they have? In this case, derived non-seed planst and seed plants are both tracheophytes (especiallys since I gave you the example of club mosses).

1. Hornworts are different from liverwort and mosses in that:
1. They contain small, lens-like chloroplasts
2. They form symbiotic associations with nitrogen fixing cyanobacteria
3. They have embryos that are contained within a modified flower
4. Both b and c
5. None of the above

This one is straight from the lecture notes - I don't do many that are so straightforward like this, but there are a few on the exam.

1. All parts of flowers in angiosperms:
1. Are produced from modified leaves
2. Are produced from modified trachieds
3. Are produced from modified apical meristems
4. Are produced from modified sepals
5. None of the above

This is a good one, which simply gives you a bunch of terms that are out of context - and makes you think about where this organ came from - likely this question will not be on the exam, since I usually only have one or two that are this 'straight-forward'.

1. Water movement from the soil into the plant occurs due to:
1. Tension developed from the evaporative loss of water from leaves
2. Positive pressure from root water absorption
3. The continuously narrowing trachied diameters from roots-to-shoots
4. The development of a gravitational effect in stems from osmotic adjustment
5. None of the above

This question forms the basis for a number of questions on the exam, including how plants respond to soil drying, how plants are constrained in how big they can get and how they deal with drought and temperature stress. It is definitional, but you should be aware of the concept.

1. Nitrogen is a main limiting factor in plant communities because:
1. Plants ‘pay’ fungal symbiosis with high nitrogen compounds
2. Plants need nitrogen for the construction of proteins
3. Plants loss nitrogen by the process of N-fixation
4. Animals continuously remove nitrogen from plant sap
5. None of the above

A slightly more conceptual question - since the last two lectures really were conceptual - they required that you put together a number of issues. About 1/5th of the exam will have these sort of questions.