109 results found

Search Results for: absent

Nervous System

    THE is the most complicated and highly organized of the various systems which make up the human body. It is the... Read More

Gene Action – Operon Hypothesis

Reviewed by: Mary Anne Clark, Ph.D. Some genes are switched on or off depending on environmental conditions. The... Read More

Peristalsis

What is Peristalsis? Peristalsis is the series of involuntary, wave-like muscle movements in the cylindrical, hollow tube... Read More

Aves

Aves Definition What are birds classified as? Birds constitute the class Aves of the kingdom Animalia. How to define Aves?... Read More

Endocytosis

Endocytosis Definition What is endocytosis in biology? Endocytosis is a cellular process by which a cell internalizes any... Read More

Archaea

Archaea is a group of prokaryotic life forms distinct from bacteria forming a separate domain of life. They possess... Read More

Apomixis

Apomixis Definition Just like any other organism, the process of reproduction is pivotal to the life cycle of plants. There... Read More

Anoxia

Definition noun (1) A condition in which oxygen is completely absent or depleted. (2) Severe hypoxia; lack of oxygen... Read More

Leukocyte

Leukocytes, also called the white blood cells (WBCs), inhabiting our immune system are the cells that exhibit astonishing... Read More

Metaphloem

Definition noun, plural: metaphloems A component of the primary phloem that develops often following the differentiation of... Read More

Dichotomous

Several English words are widely used across different fields of Science. One such term is dichotomous. We often use this... Read More

Stipulate

Stipulate Definition Stipulate meaning: Stipulate typically refers to a specific feature or characteristic of a plant's... Read More

Stems

External Form of a Woody Twig A woody twig, or stem, is an axis with leaves attached. The leaves are arranged in various... Read More

Biuret test

In this article we will answer the following three questions: What is a Biuret Test?  What does biuret test for? What is... Read More

Primary phloem

Definition noun The type of phloem derived from the primary meristem during the development of a vascular... Read More

Deoxyribonucleic acid

Deoxyribonucleic Acid (DNA) Definition A nucleic acid refers to any of the group of complex compounds made up of linear... Read More

Dark respiration

Definition noun (1) A form of respiration in plants where carbon dioxide is released without the aid of (sun)light. (2)... Read More

Tracheary elements

Definition noun (botany) The principal conductive cells of the xylem associated with the conduction of water and minerals... Read More

Softwood

Definition noun (botany) The wood (secondary xylem) of a gymnosperm tree Supplement Vascular plants (tracheophytes) are... Read More

Secondary xylem

Definition noun, plural: secondary xylems The xylem formed as a result of the secondary growth from the vascular... Read More

Leaves

Leaves are highly efficient solar energy converters. They capture light energy and through the process of photosynthesis.... Read More

Regulation of Organic Metabolism, Growth and Energy Balance

Organic Metabolism Events of Absorptive and Post-absorptive States. The absorptive state is the period during which... Read More

Plant Cells vs. Animal Cells

Plant Cells Most cells are not visible with the naked eye. However, with microscopes of various types, plant cells can be... Read More

Fundamental niche

Definition noun The full range of environmental conditions and resources an organism can possibly occupy and use,... Read More

Antecubital fossa

Antecubital Fossa Definition The antecubital fossa or the cubital fossa is the triangular-shaped hollow depression between... Read More

Facultative anaerobe

Facultative Anaerobe Definition What does facultative anaerobe mean? Facultative organisms are the most adaptable... Read More

Allopatric speciation

We can define speciation as a process by which the novel genetically independent group of organisms are formed through the... Read More

Physical Development in Humans

The Newly Born Child Depending on the nutrients available to the child within pregnancy and the genetic makeup of the... Read More

Chlorophyta

Chlorophyta Definition Chlorophyta is a taxonomic group (a phylum) comprised of green algae that live in marine habitats.... Read More

Regeneration in humans – Finding the gene switch

Regeneration in humans is much more limited compared in other animals. Say for instance when one lost a limb, much as well... Read More

Community Patterns

By: Maria Victoria Gonzaga In the previous lesson, we learned what a population is, its attributes, and processes... Read More

Rhizoids

Rhizoids are a structure in plants and fungi that functions like a root in support or absorption. In fungi, rhizoids are... Read More

Spermatid

Spermatid Definition What are spermatids? Let us define spermatid and understand its role in reproduction. A spermatid... Read More

Anaerobic respiration

Anaerobic Respiration Definition What is anaerobic respiration? Anaerobic (cellular) respiration is a respiratory process... Read More

Apocrine gland

The human body is a complex assemblage of many different organs, systems, glands, bones, and tissues. Weighing any one over... Read More

Sessile plant

Definition noun, plural: sessile plants (botany) Any of the flowering plants lacking petioles. Supplement Flowering plants... Read More

Chlorenchyma

Definition noun A parenchyma cell with chloroplasts, and is therefore photosynthetic Supplement Vascular plants are... Read More

Uridine monophosphate

Definition noun plural: uridine monophosphates (biochemistry) A nucleotide composed of uracil, ribose and a phosphate... Read More

Thymidine triphosphate

Definition noun plural: thymidine triphosphates (biochemistry) A nucleotide composed of thymine, deoxyribose and three... Read More

Thymidine diphosphate

Definition noun plural: thymidine diphosphates (biochemistry) A nucleotide composed of thymine, deoxyribose and two... Read More