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Nucleic acid digestion - brush border enzymes, end products & transport mechanism

By: HWC, Views: 7508

• Further digestion occurs at the microvilli (brush border) of the epithelial cells of the villi in the small intestine. • Two brush border enzymes complete nucleic acid digestion: • Phosphatases, which catalyze the cleavage of a phosphate to form a nucleoside (nitrogenous base and pent...

Hormonal feedback loop components

By: HWC, Views: 7830

The endocrine system maintains many body conditions within normal limits with feedback loops. Each endocrine feedback loop maintains homeostasis using the following components: ■ Stimulus - a change in a body condition. ■ Production cell - an endocrine cell that produces a hormone after b...

HIV Infection: Viral life cycle

By: HWC, Views: 7071

The series of steps that HIV follows to multiply in the body. The process begins when HIV encounters a CD4 cell. The seven steps in the HIV life cycle are: 1) binding; 2) fusion; 3) reverse transcription; 4) integration; 5) replication; 6) assembly; and 7) budding. Many viruses f...

The Lac Operon in E. Coli

By: Administrator, Views: 11790

The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. Although glucose is the preferred carbon source for most bacteria, the lac operon allows for the effective digestion of lactose when glucose is no...

What are the Parts of a Plant Cell?

By: HWC, Views: 6775

Every chloroplast in a plant cell is packed with stacks of flattened sacs called thylakoids. The thylakoid membranes contain chlorophyll, as well as most of the other components required for the light reactions of photosynthesis. The chlorophyll-containing structures within the membranes are c...

Olfaction. or the sense of smell

By: HWC, Views: 5147

Do you ever wonder how you can distinguish thousands of different odors? Olfaction. or the sense of smell, is used by all mammals to navigate, find food, and even find mates. We have millions of olfactory receptors for smelling in our nose. These receptor neurons bind water-soluble or volatil...

Type of Transport - Active and Passive Processes

By: HWC, Views: 7951

Active transport moves materials from lower to a higher concentration, while passive transport moves materials from higher to lower concentration. Active transport requires energy to proceed, while passive transport does not require the input of extra energy to occur. Transport processes that ...

Rods and Cones Animation

By: Administrator, Views: 11148

A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiation) into signals that can stimulate biological processes...

Digestion Animation

By: Administrator, Views: 11348

The mouth or oral cavity is formed by: - The hard and soft palates at the top or roof - the cheeks - the tongue - the lips Contains the teeth and salivary glands. The gingivae (gums) surround the necks of the teeth. The lingual frenulum is a thin fold of mucous membrane that connects...