Biological Processes: From Cells to Organisms
Goiter and Diabetes
Goiter: Pathological inflammation of the thyroid gland. Diabetes: Disorder in the production of the quantity of insulin needed.
Tropism in Plants
Tropism: Growth responses with which plants react to different external stimuli. Phototropism: Growth toward the light or in the opposite direction. Photojournalism: Variable duration of daylight and darkness in the year. Blooming: Process affected by the photoperiod. Geotropism: The plant’s response to gravity. Thigmotropism: The plant’
Read MorePlant Reactions, Hormones, Movements, and Seed Development
Item 12: The Function of Relation
The function of relation consists of the capacity that living things have to capture internal and external stimuli and prepare responses that ensure their survival. The reaction usually occurs with a movement or by secreting hormones. Plants detect stimuli because they have specialized cells that function as receptors, and these receptors are found in the epidermis of organs.
Types of Receptors
There are different types of receptors depending on the stimulus:
- Photoreceptors
Animal Transport Systems: From Hidrolinfa to Human Circulation
Transportation Systems
Acquired nutrients are distributed among all the cells in your body to ensure the proper functioning of animal metabolism. Waste products are expelled outside. Animals with simple structures do not need a transport system, since cells may acquire or expel substances from the environment in which they live. However, animals with highly complex needs require a circulating medium which serves to distribute nutrients and collect metabolic waste. In many cases, it also requires
Read MoreTypes of Environmental Pollutants and Their Health Impacts
Classification of Pollutants
Pollutants can be classified according to their specific characteristics:
- Physical agents
- Chemical agents
- Biological agents
- Psychological pollutants
Physical Pollutants
Physical contaminants alter the environment’s quality by their mere presence. They are characterized by an energy exchange between a person and the environment at a rate the body cannot withstand. Radioactivity (natural or artificial) is a significant example of physical pollution related to environmental geology.
Read MoreCellular Organelles: Functions and Processes
The Endoplasmic Reticulum
The endoplasmic reticulum (ER) is a network of tubules and flattened sacs. Its membrane constitutes about 50% of all cell membranes, and it is continuous with the outer nuclear envelope. There are two types:
- Smooth Endoplasmic Reticulum (SER): Lacks ribosomes.
- Rough Endoplasmic Reticulum (RER): Has ribosomes attached to its cytosolic side.
Functions of the Smooth Endoplasmic Reticulum (SER)
- Lipid Synthesis: Manufactures lipids (phospholipids and cholesterol) and their derivatives,
Five Kingdoms of Life: Characteristics and Classification
Monera: Prokaryotes
Prokaryotes are single-celled organisms with a very simple structure. Bacteria are prokaryotes and come from more primitive groups with similar body structures. Their evolution traces back to a common ancestor, an anaerobic prokaryote.
- Cyanobacteria: Responsible for the increase of oxygen in the atmosphere thanks to their photosynthetic capacity.
Prokaryotes are classified into two major domains:
- Archaea: These bacteria live outdoors, have no murein cell wall, and their lipids are