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How does an animal choose what food to eat?

By: HWC, Views: 6112

One might assume that natural selection has influenced the foraging behaviors of animals, and that most animals forage efficiently, spending the least energy to gain the most nutrients. This is the underlying assumption of optimality modeling, a scientific approach to studying foraging behavior. ...

Role of the respiratory system - effect of altered ventilation rates

By: HWC, Views: 7146

• The respiratory system regulates blood pH by controlling the amount of carbon dioxide removed from the blood. • Near systemic cells, carbon dioxide forms bicarbonate ions in the blood. H+ ions are also released, thereby decreasing blood pH. • At the alveolar capillaries, bicarbonate io...

Carbohydrate Metabolism: Introduction to renal processes and filtrate formation and composition

By: HWC, Views: 6881

• At the nephron, the three process responsible for the formation of urine include: • Glomerular filtration. • Tubular reabsorption. • Tubular secretion. • During filtration, a filtrate is formed within the renal tubule. • Reabsorption is the conserving of water and many s...

Carbon fixing adaptations Animation

By: HWC, Views: 309

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...

Regulation of GFR: autoregulation via myogenic mechanism Myogenic mechanism

By: HWC, Views: 8098

• GFR can be regulated by adjusting: • Blood flow in and out of the glomerular capillaries. • Surface area of glomerular capillaries. • There are three main ways to make these adjustments: • Renal autoregulation. • Nervous regulation. • Renal autoregulation occurs when...

Exocytosis - secretion

By: HWC, Views: 6618

Exocytosis is another method of vesicular transport that moves large volumes Of fluid or chemicals out of the cell. It is a process by which a cell transports secretory products through the cytoplasm to the plasma membrane. A examples of cellular secretory products: 1. Secreted protein - enzym...

Bone processes - resorption and deposition, remodeling and response to stress in adult bones

By: HWC, Views: 6899

• The process of remodeling bone tissues involves bone cells resorbing or depositing minerals into bone tissue. • During resorption, bone cells break down bone tissue and release calcium and other minerals for use by other cells in the body. • Bone cells also rebuild bone tissue by depo...

Role of the urinary system - acidosis and alkalosis

By: HWC, Views: 6854

• Tubular cells of the proximal convoluted tubule and collecting tubules can alter filtrate pH and therefore blood pH. • These cells can affect blood pH with two coupled mechanisms: • Reabsorption of bicarbonate ions. • Secretion of hydrogen ions. • The reabsorption of bicarbonate...

Hydrogen bonds vs. Ionic bond

By: HWC, Views: 5444

The slight positive charge of a hydrogen atom in a water molecule can attract an atom with a slight negative charge, such as the nitrogen in a molecule of ammonia. This forms a hydrogen bond between the two atoms. Hydrogen bonds join the two strands of a DNA molecule. Although hydrogen bo...