Biology Terms +

A method of using the presence of proteins "A", "B", or both at the surface of red blood cells to characterize an individual's blood type, while "O" signifies the absence of both of the proteins: The ABO blood typing classifies blood into four groups or types; A, B, AB, and O, and each one has.a special antigen and antibody blend or mixture.

Premature, spontaneous, or induced expulsion of the embryo or fetus from the uterus.

Spontaneous abortion is also called miscarriage.

Bernita's pregnancy ended in an abortion which caused her much sadness.

The uptake of water and solutes from the environment by a cell or a multi-celled organism: Absorption is the movement of nutrients, fluid, and ions across the gut lining and into the internal environment.

Any of a variety of light trapping pigments which extend the range of wavelengths for photosynthesis beyond those absorbed by chlorophylls (green coloring matter of leaves and plants which are essential to the production of carbohydrates by photosynthesis): Accessory pigments are non-chlorophyll pigments helps to absorb light but send all the energy to a chlorophyll.

Wet acid deposition or the falling of rain (or snow) rich in sulfur and nitrogen oxides: Acid rain is caused mostly by pollution in the atmosphere like sulphur dioxide or carbon dioxide.

1. A reference to a solution which consists of an excess of hydrogen ions relative to hydroxyl ions (having one oxygen and one hydrogen atom): Acidity is the amount of acid that exists in a mixture and is normally shown in terms of pH.
2. The concentration of acid in a substance: The sharpness, sourness, or acidity is certainly present in lemon juice when it is tasted!!

An animal that lacks a fluid-filled cavity between the gut and the body wall: Examples of acoelomate are flatworms, jellyfish, and nemertea.

A sound used as a form of intraspecific communication: Acoustical signals are used within or occur among the members of the same species.

1. Cytoskeletal protein (microtubules, microfilaments, and larger filaments that function as a structural support and transport mechanism): Actin is a subunit of microfilaments, or the smallest of the cytoskeletal filaments.
2. A protein which is abundantly present in many cells: Actin is especially present in muscle cells, that significantly contribute to the cell's structure and motility.

Actin can very quickly assemble into long polymer rods called microfilaments. These microfilaments have a variety of roles in that they form part of the cell's cytoskeleton, they interact with myosin to permit movement of the cell, and they pinch the cell into two during cell division.

In muscle contraction, filaments of actin and myosin alternately unlink and chemically link in a sliding action.

The energy for this reaction is supplied by adenosine triphosphate; which is, the major energy source within a cell to drive a number of biological processes, such as photosynthesis, muscle contraction, and the synthesis of proteins.

The change in the potential difference (voltage) across the membrane of a nerve cell when an impulse passes along it: An action potential is a variation in potential (from about -60 to +45 millivolts) that accompanies the passage of sodium and potassium ions across the membrane.

A momentary change in electrical potential on the surface of a nerve or muscle cell that takes place when it is stimulated, especially by the transmission of a nerve impulse: Action potentiality can be exemplified as an abrupt, brief reversal in the resting membrane potential of a neuron and other excitable cells.

Action potentiality can also be explained as the local voltage change across a cell wall as a nerve impulse is transmitted.

The energy or power needed to start a response: For each type of reaction, activation energy is the minimum amount of collision energy that will drive reactant molecules to an activated condition, from which the reaction will proceed spontaneously.

Any aspect of form, function, or behavior which helps the individual organism to survive and reproduce under prevailing conditions: Adaptive traits are a phenotypic traits that have functional roles in each single organism and which perpetuate and have evolved through natural selection.

A way of life available for organisms which are physically, ecologically, and evolutionarily equipped to live it; such as, "catching insects in the air at night".

A connective tissue having an abundance of fat-storing cells and blood vessels for transporting fats: The adipose tissue is a connective tissue that serves as an energy reserve and also pads some organs.

Adipose tissue is normally called "fat tissue" and consists of large spherical cells filled with fat. Major layers are in the inner layer of the skin and around the kidneys and heart.