Related Concept Videos

Tonicity in Animals00:59

Tonicity in Animals

The tonicity of a solution determines if a cell gains or loses water in that solution. The tonicity depends on the permeability of the cell membrane for different solutes and the concentration of nonpenetrating solutes in the solution within and outside of the cell. If a semipermeable membrane hinders the passage of some solutes but allows water to follow its concentration gradient, water moves from the side with low osmolarity (i.e., less solute) to the side with higher osmolarity (i.e.,...
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Tonicity in Animals01:16

Tonicity in Animals

Tonicity describes the amount of solute in a solution. The measure of the tonicity of a solution, or the total amount of solutes dissolved in a specific amount of solution, is called its osmolarity. Three terms—hypotonic, isotonic, and hypertonic—are used to relate the osmolarity of a cell to the osmolarity of the extracellular fluid that contains the cells. In a hypotonic solution, such as tap water, the extracellular fluid has a lower concentration of solutes than the fluid inside...
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Animal Mitochondrial Genetics02:59

Animal Mitochondrial Genetics

Among all the organelles in an animal cell, only mitochondria have their own independent genomes. Animal mitochondrial DNA is a double-stranded, closed-circular molecule with around 20,000 base pairs. Mitochondrial DNA is unique in that one of its two strands, the heavy, or H, -strand is guanine rich, whereas the complementary strand is cytosine rich and called the light, or L, -strand. Compared to nuclear DNA, mitochondrial DNA has a very low percentage of non-coding regions and is marked by...
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The Influence of Affect on Cognition01:29

The Influence of Affect on Cognition

Positive affect significantly influences cognitive processes, including evaluation, memory, creativity, and social judgments. Compared to negative affect, positive emotional states promote more favorable interpretations of stimuli, cognitive flexibility, and heuristic processing. These effects highlight emotions' powerful role in shaping how individuals perceive, remember, and interact with the world.Influence on Evaluation and AttributionWhen individuals experience positive affect, they are...
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The Influence of Cognition on Affect01:29

The Influence of Cognition on Affect

Cognition plays a pivotal role in shaping emotional experiences, as demonstrated by Schachter and Singer’s two-factor theory of emotion. According to this model, emotion arises from a combination of physiological arousal and cognitive interpretation. The body’s physiological response to stimuli is ambiguous and only gains emotional significance through cognitive labeling. For instance, an increased heart rate and adrenaline surge while standing near an attractive person may be...
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Bioavailability: Influencing Factors01:22

Bioavailability: Influencing Factors

Bioavailability refers to the extent and rate at which a drug reaches systemic circulation in its active form. Extent refers to the amount of the drug that makes it into circulation, while rate is the speed at which it enters circulation. It is influenced by several factors critical for optimizing drug formulations, dosing regimens, and therapeutic outcomes.Physicochemical properties of drugs and formulationsThe solubility, stability, and dissolution rate of a drug significantly impact its...
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