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How does an animal choose what food to eat?

By: HWC, Views: 7192

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. ...

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

By: HWC, Views: 7917

• 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: 1811

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: 9209

• 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...

Primary Active Transport - electrochemical gradient and ion transport / water movement

By: HWC, Views: 7852

Energy derived from ATP changes the shape of a transporter protein which pumps a substance across a plasma membrane against its concentration gradient An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consis...

Hydrogen bonds vs. Ionic bond

By: HWC, Views: 6524

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...

Acids and bases - definition

By: HWC, Views: 7632

Acids and bases are found all around your house. For example, if you open your pantry or refrigerator, you might see a lot of acids. Fruit juice, soda pop, vinegar, and milk are all examples of acids. The word acid actually comes from a Latin term meaning ''sour.'' Many materials, like sugar for ...

Structures that affect circulation - kidneys and blood volume and skeletal muscle pumping

By: HWC, Views: 8307

• Kidneys regulate blood volume and blood osmolarity via salt and water reabsorption. • Increased reabsorption increases blood volume and venous return (and CO). • Decreased reabsorption Increases urine production, which decreases blood volume and venous return (and CO). • Systemi...

Bond in biological molecules (Ionic, Covalent and Hydrogen bonds)/ How atoms bond?

By: HWC, Views: 5075

Sodium atoms and chloride atoms have unfilled orbitals in their outer shells. The lone electron in the outermost shell of a sodium atom can be pulled or knocked out. This ionizes the atom. It is now a positively charged sodium ion. A chlorine atom has an electron vacancy in its outer shell and...