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Egg and Sperm Formations in Animals Animation

By: HWC, Views: 417

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. ...

Major Elements in Biological Molecules: Nucleic acids

By: HWC, Views: 6600

DNA and RNA are nucleic acids (polymers of nucleotides). Two polymers with complementary nucleotide sequences can pair with each other. This pairing endows nucleic acids with the ability to store, transmit, and retrieve genetic information. Two strands of DNA pair by hydrogen bonding. A compon...

Non-specific disease resistance mechanisms & Skin's defense barriers

By: HWC, Views: 6559

• Non-specific disease resistance acts quickly to fight a wide variety of invaders. • Mechanisms include: • Barriers • Antimicrobial substances • Cellular defenses • Inflammation • Fever Barriers - types • Physical and chemical bathers prevent invasion by micro...

Types of energy transfer reactions: oxidation-reduction reactions and ATP generation reactions

By: HWC, Views: 7188

■ Metabolism balances anabolic and catabolic reactions. ■ Anabolism is energy transfer from ATP to simpler molecules in order to build them up into larger, more complex molecules. ■ Catabolism is breaking down larger, more complex molecules, usually to transfer energy from them in order...

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

By: HWC, Views: 7212

• 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...

Stages of Mitosis - Prophase, Prometaphase, Metaphase, Anaphase & Telophase

By: HWC, Views: 6284

In mitosis, the nucleus divides to produce two nuclei that are genetically identical to each other and to the parent nucleus. To prepare for division, the DNA replicates in the preceding interphase. Although the chromosomes are not yet compacted and visible as discrete bodies, we illustrate them ...

Baroreceptor Reflex

By: HWC, Views: 5999

Baroreceptors located In the carotid sinus and the arch of the aorta respond to increases in blood pressure. Increased blood pressure stretches the carotid arteries and aorta causing the baroreceptors to increase their basal rate of action potential generation. Action potentials are conduct...

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

By: HWC, Views: 6427

• 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...

Net filtration pressure and lymph formation, edema & blood velocity

By: HWC, Views: 6415

Bulk flow -net filtration pressure and lymph formation • The net filtration pressure (NFP) is the force promoting filtration minus the force promoting reabsorption. • At the arterial end of an ideal capillary, the filtration pressures are stronger. The result: net filtration. • At t...