Enzyme Substrate Complex Definition The enzyme substrate complex is a temporary molecule formed when an enzyme comes into perfect contact with its substrate. Without its substrate an enzyme is a slightly different shape. The substrate causes a conformational change, or shape change, when the substrate enters the active site. The active site is the area … Read more

Secondary Succession Definition One of the two main forms of ecological succession, secondary succession is the process relating to community growth or change that takes place when a habitat is disturbed or damaged. Whilst primary succession takes place when pioneer species inhabit a newly formed substrate lacking in soil and biotic organisms (such as rock … Read more

Definition A concentration gradient occurs when a solute is more concentrated in one area than another. A concentration gradient is alleviated through diffusion, though membranes can hinder diffusion and maintain a concentration gradient. Overview “Concentration” refers to how much of a solute is in a given amount of solvent. A corner of a water tank … Read more

Nervous Tissue Definition Nervous tissue is the term for groups of organized cells in the nervous system, which is the organ system that controls the body’s movements, sends and carries signals to and from the different parts of the body, and has a role in controlling bodily functions such as digestion.  Nervous tissue is grouped … Read more

Leaf Definition The term leaf refers to the organ that forms the main lateral appendage on the stem of vascular plants. In general, leaves are thin, flat organs responsible for the photosynthesis of the plant. Although photosynthesis typically only occurs on the upper surface of the leaf, it can occur on both sides in some … Read more

Dichotomous Key Definition A dichotomous key is a tool created by scientists to help scientists and laypeople identify objects and organisms. Typically, a dichotomous key for identifying a particular type of object consists of a specific series of questions. When one question is answered, the key directs the user as to what question to ask … Read more

Heterotroph Definition A heterotroph is an organism that cannot manufacture its own food by carbon fixation and therefore derives its intake of nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are secondary and tertiary consumers. Carbon fixation is the process of converting inorganic carbon (CO2) into … Read more

Anatomical Position Definition Standard anatomical position is a way of describing the anatomy of an organism so that it is easy to understand what part of the body is being talked about no matter what direction the organism is facing or where its appendages/limbs are. In humans, standard anatomical position is defined as standing up … Read more

Flagellum Definition Flagellums are microscopic organelles that help cells and microorganisms move. In Latin, flagellum means whip, similar to the whipping motion flagella (plural) frequently use for locomotion. In some organisms, specialized flagella function as sensory organelles that detect temperature and pH changes. Function of Flagellum A flagellum is a filamentous protein structure found in … Read more

The Basics In freshwater aquariums, the oscar fish (or simply oscar) is a species from the cichlid family. Oscars originate from South America – namely the Amazon River basin – but have been introduced all over the world. There are many types of Oscar fish available as aquarium species. A common variety is the “tiger … Read more