Lab Exam #2 Flashcards
What are stomata and what are their purpose?
A plant’s epidermis contains millions of tiny pores called Stomata, (plural for stoma).
The main purpose of the stomata is the regulation of gas exchange of CO2 and O2, which is a vital part of photosynthesis and is made possible by the guard cells surrounding the stomata.
CO2 enters into the stomata and O2 is released.
What factors will close stomata?
-High temperatures
-High ozone
-Contact with pathogenic bacteria
What factors will open stomata?
-High humidity
-Low CO2
-Illumination of guard cells by red/ blue light
If a leaf was treated with ABA (abscisic acid) what would happen?
The ABA binds to the ABA receptors in the guard cells.
Activated outward diffusion of K+ and it causes water to leave and close the stomata.
If a leaf was treated with SA (salicylic acid) what would happen?
SA acts on guard cells. It inactivates the inward directed K+ channels
If a leaf was treated in a phosphate buffer in the dark what would happen?
Will not undergo photosynthesis
If a leaf was treated in a phosphate buffer in the light what would happen?
Will undergo photosynthesis.
Describe the role of auxin in plant growth
Auxin is a plant hormone that stimulates growth by elongating the stem and cells.
It has apical dominance because it is inhibiting the growth of the lateral axillary buds (no side shoots or leaves) while it continues to promote vertical growth of the plant upwards towards the light.
Where is auxin produced in a plant?
Tip region of the plant stem.
Mitosis and meiosis. List 3 differences between them:
Mitosis:
-Produces diploid cells
-Produces 2 identical daughter cells
-no recombination (crossing over)
Meiosis:
-Produces haploid cells
-Produces 4 different daughter cells
-Recombination in prophase I
What does SAM stand for?
Shoot Apical Meristem
If water enters a red blood cell what will happen?
becuase the cell is hypertonic to the water the water will rush into the cell and cause it to burst
HEMOLYSIS
If water flows out of a red blood cell what will happen?
Crenation.
The cell will shrivel
What is the outcome if a red blood cell is placed in a 0.9% NaCl solution?
Solution is: Opaque
Cell condition: Normal
Tonicity: Isotonic
What is the outcome if a red blood cell is placed in a 10% NaCl solution?
Solution is: Opaque
Cell condition: Crenated
Tonicity: Hypertonic
What is the outcome if a red blood cell is placed in dH2O solution?
Solution is: Transparent
Cell condition: Hemolyzed
Tonicity: Hypotonic
What is plasmolysis?
The shrinking of the cytoplasm of a plant cell in response to water diffusing out of the cell and into a hypertonic solution surrounding the cell.
What is the outcome if a plant cell is placed in a dH2O solution?
Cell condition: Turgid
Tonicity: Hypotonic
Water flowed into cell, filled up the central vacuole and pushed the chloroplasts to the outer regions.
What is the outcome if a plant cell is placed in a 20% NaCl solution?
Cell condition: Plasmolysis
Tonicity: Hypertonic
Water flowed out of the cell and shrunk the central vacuole and caused the chloroplasts the gather in the middle
What is the difference between crenation and plasmolysis?
Plasmolysis is for a plant cell. The outer layer is too stiff to shrivel so the internal cytoplasm shrivels instead.
Crenation is the whole cell (blood cell) shriveling
What is dialysis tubing made of and what can pass through it?
Made of cellulose which has hydrophylic properties.
Small polar molecules can pass through.
Chloride and sulfate CAN
Protein and starch CANT
What is the formula to calculate weight change?
Wt = (Wf - Wi) / Wi x 100
How do you calculate concentration and volume?
C1V1 = C2V2
jeoparty
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