Simplified Diagram Of Cross Sections A Leaf From C3 …
Simplified Diagram Of The Cross Section A Leaf From C3 Plant
Leaf Structure Cross-Section - YouTube
Students start the unit by learning about leaf structure. First, they are required to make a diagram of a leaf cross-section and a chloroplast using their textbook and labeling and writing descriptions of the functions of all the parts. This can be done as a homework assignment the previous night to give more class time for the lab work. Once they are familiar with what they should be looking for, I have them observe, draw and label prepared cross-sections of leaves using a microscope. After a review of the function of stomata from their diagram assignment, students then will observe stomata under the microscope. The best plant for this is called Wandering Jew, It has leaves with a lot of very bright purple pigment on the underside, but the guard cells show up as bright green. There is no mistaking them. Students do not even have to peel the leaf. All that is required is to make a wet mount slide of a small piece of the leaf with the underside facing up. Students draw, measure, and count the number of stomata per unit area of leaf. They also observe what happens to the stomata when a solution of salt water is drawn under the cover slip, causing the guard cells to lose turgor pressure and close the stomata. Once they know what to look for, I ask students to predict how the stomata might be different on different types of leaves. Will size vary? Number? Location? Shape? They then select several different types of leaves and test their hypotheses by recording their observations and conclusions in their lab notebooks. Class closes with a discussion of the results.
Reduced Oxidized Leaf cross section Mesophyll Chloroplast Cytochrome Complex IB Assessment Statements: 3.8.1 3.8.8 3.8.7 3.8.6 3.8.5 3.8.4 3.8.3 3.8.2 State that photosynthesis involves the conversion of light energy into chemical energy.
Leaf Structure Cross-Section ..
After a discussion about what pigments might be in chloroplasts, I have the students gather several types of leaves from trees outside the classroom. Since I am usually teaching this unit in the early fall, I tell them to collect some leaves that are starting to change colors, as well as some green leaves of the same type. I always have on hand some Southern Magnolia leaves. This tree is an evergreen, has very thick leaves, and always gives wonderful results in case other leaves have already started losing their chlorophyll. Paper chromatography is a method of separating molecules by solubility, size and their attraction to the paper. This lab is a modification of the AP Biology Lab 4, part A. Instead of preparing a solution of the leaf pigments, I have students use the edge of a coin to press the leaf pigments into the chromatography paper in a straight line across the bottom of the strip, about one half inch up. The pigment must be above the level of the solvent or it will all end up in the bottom of the jar. This method saves prep time and students can test a variety of different leaves. They must take care, however, to get a thick straight line of pigment on the paper, and not to tear through the paper with the coin. The strip should be about 2.5" by 4", and folded in half lengthwise. The students can put a line of pigment at the bottom of each half and the fold makes it stand up in the chromatography jar. (See Figure 3.) This method works best with actual chromatography paper rather than the coffee filters sometimes recommended as an alternative, because the thicker paper stands up better to being pressed by the coin. The strip is then placed in chromatography solvent—90% petroleum ether and 10 % acetone. Use a jar with a lid to contain the fumes. If you do not have these chemicals, alcohol or fingernail polish remover may work.
here is the cross section of a "typical" C 3 leaf.
Basic structure of a leaf shown in cross-section
Whole-leaf cross sections (insets) ..
Leaf cross section
The following diagram is of a cross section of a plant leaf.
the interior tissue of the leaf Each mesophyll cell contains 30–40 chloroplasts Figure 10.4 Leaf cross section ..
Leaf Cross Section Diagram Leaf Labeled ~ Elsavadorla
Reduced Oxidized Leaf cross section Mesophyll Chloroplast Cytochrome Complex IB Assessment Statements: ..
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