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The Pressure Flow Model in a Plant

By: HWC, Views: 7236

The vascular system of plants has two transport tissues, called xylem and phloem. Xylem transports water and minerals, while phloem transports a variety of dissolved substances, including sugars and amino acids, throughout the plant. Water in the xylem always moves up, in the direction from th...

Carbohydrate digestion (brush border enzymes, end products) & Carb absorption (fructose, galactose)

By: HWC, Views: 7859

• Carbohydrate digestion concludes in microvilli of the small intestine, in brush border epithelial cells. Carbohydrate digestion -brush border enzymes • Four brush-border enzymes are involved: • Alpha-dextrinase breaks down alpha-dextrin chains by removing glucose units. • Sucras...

Carbon fixing adaptations Animation

By: HWC, Views: 1962

Different plants trap carbon by different pathways. Most C3 plants evolved in moist, temperate zones. On hot dry days they close their stomata to conserve water and oxygen accumulates. Under these circumstances, the enzyme rubisco uses oxygen in an inefficient reaction that competes with t...

Introduction to Sickle Cell Anemia

By: Administrator, Views: 11311

Sickle cell anemia (sickle cell disease) is a disorder of the blood caused by an inherited abnormal hemoglobin (the oxygen-carrying protein within the red blood cells). The abnormal hemoglobin causes distorted (sickled appearing under a microscope) red blood cells.

Sperm Formation

By: HWC, Views: 5890

Spermatogenesis takes place inside the seminiferous tubules. Diploid spermatogonia located near the outer edge of the tubule divide mitotically to form primary spermatocytes. The first meiotic division produces secondary spermatocytes with a haploid number of duplicated chromosomes. T...

Egg and Sperm Formations in Animals Animation

By: HWC, Views: 2115

Inside the ovaries of a female animal are diploid germ cells called oogonia. An oogonium grows to become a primary oocyte. This large cell is still diploid. Meiosis I followed by unequal cytoplasmic division produces one large secondary oocyte and a smaller polar body. Both are haploid. ...

Red alga life cycle Animation

By: HWC, Views: 2068

Life cycle of Porphyra. The most conspicuous part of this algal life cycle is the haploid gametophyte. This sheetlike form is collected and dried for use as nori, the wrapping for sushi. Gametes form in packets interspersed between vegetative cells near the sheet margins. The gamet...

Regulation of GFR: autoregulation via tubuloglomerular feedback, neural & hormonal regulation

By: HWC, Views: 9045

• When blood pressure is above normal, rapid filtrate flow reduces ion retention so filtrate in tubule has more Na+, C1-, and water. • It is believed that vasoconstricting chemicals from the juxtaglomerular cells are released when the macula densa cells detect higher water and ion levels in ...

Lipid absorption - end products & transport mechanism

By: HWC, Views: 7423

• The end products, fatty acids and monoglycerides, depend on bile salts for absorption. • Bile salts form micelles (tiny spheres), which ferry fatty acids and monoglycerides to epithelial cells. • Free fatty acids, monoglycerides, and some phospholipids and cholesterol molecules, dif...