94 results found

Search Results for: absent

Absent

Absent 1. Being away from a place; withdrawn from a place; not present. Expecting absent friends. 2. Not existing; lacking;... Read More

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

Endocytosis

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

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

Metaphloem

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

Anoxia

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

Chlorophyta

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

Tracheary elements

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

Sphenethmoid

Definition noun It designed to both sphenoid and ethmoid regions of the cranium that surrounds the anterior portions of the... Read More

Sessile plant

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

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

Softwood

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

Mayers reflex

Mayer's reflex --> basal joint reflex opposition and adduction of the thumb with flexion at its metacarpophalangeal joint... Read More

Secondary xylem

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

Hyaline cartilage

Hyaline Cartilage Definition Firstly, let us ask, what is cartilage? Cartilage is a tough and flexible material. It can be... Read More

Complement fixation test

Definition noun (immunology) A form of immunological test for the detection of the presence of either a particular antibody... Read More

Anaerobic respiration

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

Fundamental niche

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

Endomembrane system

Ever wondered how biomolecules are made within the cell and then they are released outside the cell for use by the body?... Read More

Semilunar valve

The human heart structure consists of heart chambers (2 atria and 2 ventricles) that differ functionally from each other.... Read More

Thymidine diphosphate

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

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

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

Leaves

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

Plant cell

Plant Cell Definition A plant cell refers to any cell of a plant. It is the structural and functional unit of plants. Plant... 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 monophosphate

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

Hypomelanism

Definition noun A condition in which there is a partial lack of the melanin, thus, a reduced... Read More

Nucleobase

Definition noun plural: nucleobases (biochemistry) The base in the nucleic acid, e.g. purines and pyrimidines Details ... Read More

Patellar reflex

Definition noun, plural: patellar reflexes A stretch reflex wherein the anterior muscles of the thigh contracts by reflex as... Read More

Sex-determining Region Y gene

Definition noun The gene that codes for the SRY protein, which is associated with the testicular development in many male... Read More