WW-P 9-12 Schools

Grades 9-12

Gibberellins are plant hormones that play a key role in germination. The photograph shows a picture of sprouts. Since they have just sprouted, gibberellins must have aided them in germination. Gibberellins are naturally occurring in plants. They are normally found in low concentrations.

Epithelial tissue, such as skin as shown in the photograph, covers the outside of the body and also lines organs and cavities within the body. The cells of the epithelial tissue are tightly packed so that it can act as a barrier against microbes, mechanical injury and fluid loss. Epithelial tissue can be classified by the number of cells and the shape of the cells on the exposed surface.

The CAM plants have adopted another photosynthetic mechanism in arid conditions. The CAM pathway is similar to the C₄ pathway. However, in CAM plants, both the step preceding the Calvin cycle and the Calvin cycle occur in the same cell but at different times. CAM plants open their stomata during the night and fix CO₂ into a four carbon compound. The Calvin cycle occurs in the same cell in the morning. The pineapple plant is an example of a CAM plant.

In the photograph, there are flowers of different colors. Some are light purple while others are a darker shade of purple, indicating the variation in the phenotype and genotype.

Dandelions are asexually reproducing organisms. They reproduce by a mechanism known as apomixes. Dandelions and other such plants produce seeds without pollination or fertilization. A diploid cell in the ovule gives rise to the embryo, and thus fertilization does not occur. The offspring are genetically identical to the parent.

Eubacteria are a kingdom that consists of single celled bacterial cells. They are prokaryotic and can be heterotrophic or autotrophic. Eubacteria can be found in many places, such as yogurt, whereas archaebacteria can be found in only extreme environments. Eubacteria also possess a peptidoglycan cell wall.

Fermentation is also known as anaerobic cellular respiration. The top two photographs show dry yeast before sugar and water was added. The left photograph on the bottom shows yeast right after sugar and water was added. The middle and right photograph show the end result of the reaction. During fermentation, aka anaerobic respiration, the yeast produces ethanol and carbon dioxide along with the 2 ATP molecules formed during glycolysis.  The bubbles indicate a presence of carbon dioxide, a product of the reaction.

The cuticle layer of a plant is the waxy layer on the leaves. This layer helps retain water within the leaves. The plant loses water through the process of transpiration. The cuticle layer along with the epidermal tissue helps retain the water.

This photograph shows the picture of a rabbit that is on dirt. Since the color of the rabbit is brown, it is difficult to spot the rabbit. The rabbit blends in with the dirt. The color of the rabbit’s fur, an example of camouflage, enables it to hide from predators, which wouldn’t be able to spot the rabbit in dirt.

During the Calvin cycle of photosynthesis, C₃ plants first produce a three carbon compound, 3-phosphoglycerate. They use the enzyme rubisco in order to fix carbon into a 3-carbon compound. On hot, dry days less sugar is produced because less CO₂ is fixed and O₂ competes with CO₂ as rubisco can sometimes bind to O₂. Potatoes are examples of C₃ plants.