Key Concepts in Biology: Variables, Energy, Genetics, and More
Key Concepts in Biology
In experiments, the independent variable is manipulated, while the dependent variable responds. The independent variable is plotted on the x-axis, and the dependent variable on the y-axis.
Energy and Ecosystems
Lions hunt in groups to conserve energy. The 10% rule states that approximately 10% of energy is transferred between trophic levels in food chains. Net energy gain refers to the final amount of energy gained or lost.
Cellular Biology
Prokaryotic cells are single-celled
Read MoreThe Nervous System: Sensory Receptors, Neurons, and Impulses
Nervous System: Functions and Components
The nervous system governs the life of relation. It processes information received to develop appropriate responses.
Sensory Receptors
Stimuli are all internal and external changes capable of generating a response from the living being. Receptors are specialized cells that capture and translate stimuli into nerve impulses. These nerve cells are connected chemically or electrically with two neurons.
Classification of Receptors
By Location
- Interoceptors: Located
Postmortem Changes: A Forensic Analysis
Cooling of the Body (Algor Mortis)
The cooling of the body after death, known as algor mortis, is influenced by several factors, including poisonings by alcohol, deaths from cold and extreme heat, and acute illnesses. Other factors include:
- Poisonings and Illnesses: Conditions such as alcohol poisoning, convulsive poisonings, heat stroke, and other acute illnesses can affect the body’s temperature regulation and, consequently, the rate of cooling after death.
- Individual Factors: Individual characteristics
Human Body Systems: Digestion, Circulation, Lymphatic
The Human Digestive System
The human digestive system consists of a sophisticated series of organs and glands that processes food. Food digestion starts in the mouth, where a transparent liquid called saliva begins the process of breaking up chemicals and forms a mass easy to swallow. This mass, bolus, goes through the throat into the esophagus, which is a 25-cm long tube that squeezes and moves the bolus into the stomach. This organ is a sack made up of strong muscle walls that squeeze food and,
Read MoreEssential Nutrients: Fueling Your Body for Life
Food and Nutrition: Fueling Your Body
Food is the voluntary process performed by human beings to eat and deliver nutrients to the body for maintenance and development. Nutrition is the collection and use of nutrients and energy obtained from food, necessary for life. Foods are processed or natural products that can be ingested, digested, and absorbed. They contain energy and nutrients and are recognized as such by a social group.
Understanding Nutrients
Nutrients are chemical substances contained in
Read MoreBacterial Growth, Culture, and Nutritional Types
Bacterial Culture and Growth
- Synchronous culture: Culture in which all bacteria divide at the same time.
- Continuous culture: Cultures of bacteria that are maintained indefinitely in the log phase.
Phases of Bacterial Growth
The normal cycle of growth in bacterial culture includes four phases:
- Lag Phase: No significant population change; cells are metabolically active, increasing in size and adapting to the medium.
- Log Phase: Cells duplicate at regular intervals, showing uniformity in metabolic activity.