Cellular Nutrition: Autotrophs, Heterotrophs, and Respiration
Cells need organic substances for two main purposes:
- Building and Repair: To rebuild structures, grow, and reproduce.
- Energy Production: To carry out activities such as movement and exchanging substances with the environment.
Living organisms obtain nutrition in two primary ways:
Autotrophic Nutrition
Autotrophs are able to capture energy from sunlight and use it to produce organic matter from inorganic substances. They take in raw materials to construct their own nutritional matter.
Heterotrophic Nutrition
Heterotrophs
Read MoreGenetic Engineering and Selective Breeding Techniques
DNA Polymerase: Sequencing vs. Cellular Function
Contrast the role of DNA polymerase in determining a DNA sequence with its role in normal cells.
In DNA sequencing, DNA polymerase replicates small pieces of DNA using normal bases and some bases that are tagged with dye. Each base can be tagged with a different color dye. The dye-tagged bases stop replication. After running the bases on a gel, scientists can determine the sequence of the DNA by reading the order of the colored bands on the gel. In
Read MoreDigestive and Respiratory Systems: Anatomy and Functions
Larynx: Anatomy and Function
The larynx is a tubular organ that connects the pharynx to the trachea, located in the front of the neck. During swallowing, communication is intercepted by a layer of cartilage (epiglottis) that prevents food from passing into the airways. It consists of the hyoid bone and the following cartilages:
- Cricoid: It is superimposed on the trachea, forming a ring with an anterior arch and a posterior seal.
- Thyroid: Forms the laryngeal prominence (Adam’s apple).
- Epiglottis: When
The Nervous System: A Comprehensive Analysis
The Nervous System
The nervous system is responsible for analyzing stimuli, both external and internal, and developing the necessary responses for the functioning of the body.
It can be distinguished into:
The Central Nervous System (CNS)
The CNS is in charge of body control and its activities.
The Peripheral Nervous System (PNS)
The PNS transmits nerve impulses from receptors to the CNS, and from the CNS to the effectors.
Central Nervous System
The central nervous system consists of the brain and
Read MoreAnimal and Plant Excretion: A Comprehensive Look
Excretion in Animals and Plants
Excretion in Animals
Excretion is the elimination of waste products resulting from cellular metabolism and is performed through urine, sweat, and breath. The excretory system carries out this process. Homeostasis consists of functions that enable organisms to balance their internal environment.
Waste Products in Animals
- Non-nitrogenous: CO2 and H2O. CO2 is eliminated through the respiratory surfaces, while water can be removed as a vapor by the same surfaces or in liquid
Cellular Biology: Tension-Cohesion, DNA, Reproduction, and Cellular Evolution
The Tension-Cohesion-Adhesion Hypothesis
Tension-Cohesion-Adhesion Hypothesis:
- Mesophyll cells lose water, creating a water deficit in the top floor, which results in negative pressure, also known as tension. The solute concentration in these cells increases, consequently increasing the osmotic pressure.
- Mesophyll cells become hypertonic in relation to the xylem, drawing water molecules into the cells.
- Water molecules are linked together due to cohesion forces (between water molecules) and adhesion