UA BSC 108 Exam 2 Questions & Answers-2024 Update.
What is a photosynthetic autotroph? - Correct Answer An organism that makes its own
food from inorganic ingredients.
What is the fluid inside chloroplasts called? - Correct Answer Stroma
What are the membranes inside chloroplasts called? - Correct Answer inner and outer
membranes
Write the overall equation for photosynthesis. - Correct Answer
6CO2+6H2O→C6H12O6+6O2
What is the primary function of pigments in photosynthesis? Name the primary pigment
used in photosynthesis. - Correct Answer Pigments absorb certain wavelengths. They
are the means by which the energy of sunlight is captured for photosynthesis. The
primary pigment used in photosynthesis is Chlorophylla-a.
Why are leaves green? - Correct Answer Their green color is from chlorophyll, a
pigment (light- absorbing molecule) in the chloroplasts that plays a central role in
converting solar energy to chemical energy.
How and where does water enter a plant? - Correct Answer Water enters root hair cells
by osmosis.
How and where does carbon dioxide enter a plant? - Correct Answer Carbon Dioxide
diffuses through small holes in the underside of leaves, called the stomata.
The light reactions take place in three stages. Name the stages and summarize the
events of each stage. 1. Photons excite electrons in the chlorophyll of the first
photosystem. These photons are then trapped by the primary electron acceptor. This
photosystem then replaces the lost electrons by extracting new ones from water. This is
the step that releases O2 during photosynthesis. 2. Energized electrons from the first
photosystem pass down an electron transport chain to the second photosystem. The
chloroplast uses the energy released by this electron "fall" to make ATP. 3. The second
photosystem transfers its light-excited electrons to NADP+, reducing it to NADPH.
List all products of the light reactions. carbon dioxide, water. Glucose, oxygen
The Calvin cycle has three main stages. Name the stages and summarize the events of
each stage. - Correct Answer "1) Carbon Fixation- The enzyme rubisco combines CO2
with 5-carbon sugar rubulose biphosphate (RuBP). The unstable product formed splits
into 2 molecules of 3-carbon 3-phosphoglyceric acid (3-PGA).
2) Reduction- Energy from 6 molecules of ATP is used to oxidize NADPH to NADP+.
Six molecules of 3-PGA are reduced, producing six molecules of energy-rich 3-carbon
sugar G3P.
3) Release of one molecule of G3P- Five of the previously created G3Ps remain in the
cycle, but one molecule is released.
, 4) Regeneration of RuBP - series of chemical reactions uses energy from ATP to
rearrange the atoms of the 5 G3P molecules, (15 total carbons), which forms 3 RuBP
molecules (15 total carbons).
These will start another turn of the cycle.
"
List all products in the Calvin cycle. - Correct Answer "6 Turns of the Calvin Cycle→ 1
C₆H₁₂O₆
6CO₂ → 1 C₆H₁₂O₆
18 ATP + 12 NADPH → 1 C₆H₁₂O₆
Left over ATP is used elsewhere by the cell. "
Give two examples of plants that use C4 photosynthesis. - Correct Answer "1) Corn
2) Sugarcane"
What environmental factor is C4 photosynthesis an adaptation for? - Correct Answer
High levels of CO2 and drought environments
Contrast carbon fixation in C4 and CAM plants. C4 plants initially attach CO2toPEP to
form the four-carbon compound OAA using the enzyme PEP carboxylase. This takes
place in the loosely packed cells called mesophyll cells. OAA is then pumped to another
set of cells, the bundle sheath cells, which surround the leaf vein. There, it releases the
CO2for use by Rubisco. By concentrating CO2in the bundle sheath cells, C4plants
promote the efficient operation of the Calvin-Benson cycle and minimize
photorespiration. CAM plants also initially attach CO2to PEP and form OAA. However,
instead of fixing carbon during the day and pumping the OAA to other cells, CAM plants
fix carbon at night and store the OAA in large vacuoles within the cell. This allows them
to have their stomates open in the cool of the evening, avoiding water loss, and to use
the CO2 for the Calvin-Benson cycle during the day, when it can be driven by the sun's
energy.
1. How does asexual reproduction differ from sexual reproduction? - Correct Answer
Asexual Reproduction involves one parent and produces offspring that are genetically
identical to each other and to the parent. Sexual Reproduction involves two parents and
produces offspring that are genetically unique.
2. What are the two main phases of the eukaryotic cell cycle? - Correct Answer "a.
Interphase
b. Mitotic phase"
3. During which phase of the cell cycle does DNA duplicate? - Correct Answer
interphase- chromosome duplication
4. What is the function of mitosis? - Correct Answer in mitosis the nucleus and its
contents, most importantly, the divided chromosomes, divide and are evenly distributed,
forming two daughter, nuclei
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