Have you ever wondered, what is your physiological age? Is it more or less than your chronological age? Physiological age determines a person’s health condition. Are we able to determine physiological age? You would think the answer is NO. but it can be done by determining telomere’s length. “Telomere is a repetitive nucleotide sequence (having no meaningful information) at each end of chromosome to protect DNA from deterioration and or from fusion with other chromosomes.” This sequence is about 3000-15000 base pairs in length. In vertebrates this repeated sequence is TTAGGG.

 

 

Cells divide and increase their number, DNA duplication also occurs. Enzymes involved in this duplication process, can’t continue duplication all the way to the end so some part of DNA is lost and chromosome is shortened. This lost part is some base pairs of telomere. Somatic cells lose about 50-100 nucleotides on each cell division. In this way, telomeres, having no meaningful information, act as CAPS preventing the important information (DNA) from deterioration and preserve the critical information. Telomeres are never tied to each other which allows chromosomes to remain segregate. Without telomeres, chromosomes would fuse with each other. Telomere Shortening Telomeres shorten because of the two major factors:

 

 

 

Oxidative stress in the body depends on lifestyle factors. Smoking, poor diet and stress can cause increase in oxidative stress. With each cell division telomeres shorten, so there are limited number of divisions that a cell can undergo, this limit is called Hayflick Limit. This is to prevent the loss of vital DNA information and to prevent production of abnormal cells. When a cell reaches this limit it undergoes apoptosis that is a programmed cell death. Telomere Lengthening to reverse telomere shortening, there is an enzyme named Telomerase that adds telomere sequence nucleotides and replenish the lost telomere nucleotides. Telomerase activity is not present in all cells. It is almost absent in somatic cells including; lung, liver, kidney cells, adult tissues, cardiac and skeletal muscles etc. In the presence of telomerase enzyme, a cell can divide to unlimited extent without ageing giving rise to tumors. That’s why it is found only in some cells in considerable concentration including germline cells and stem cells. These cells don’t show signs of ageing.

 

 

 

It is still controversial that whether telomere shortening is a reason of ageing or is a sign of ageing just like grey hair. Whatever it is, the thing is, it determines your physiological age because ageing cells mean an ageing body. Telomere shortening is related with poor lifestyle. People who are active and have a healthy lifestyle have the same telomere length as someone 10 years younger than them has. Depression causes increase in oxidative stress in the body so the higher the stress, the shorter the telomere is Link between Telomeres and Cancer “Cancer in general is defined as an uncontrollable rapid growth of cells.”

 

 

These cells have active telomerase enzyme, which doesn’t let the telomere to shorten, so no Hayflick limit reaches and cell continues to divide. This is the reason why telomerase is not used as an anti-ageing medicine because it has potential to turn normal body cells into cancerous cells. Without telomerase activity cancer cells activity would stop, which is an under research treatment for cancer. However, drugs inhibiting telomerase activity, can interfere with normal functioning of cells that require telomerase. In healthy female breast there is a portion of cells named, luminal progenitors, with critically short telomere length. In these cells telomerase becomes active causing these cells to turn into cancer cells on higher activity. To tackle breast cancer, use of telomerase inhibiting drugs should be practiced. Telomere biology is very important for understanding cancer biology and scientists are working hard on it.

 

 

Editor @ BioScience.pk 

The following list shows most commonly used symbols in biology and their meaning arranged in a alphabetical manner.

 

Cell is a fundamental, structural and functional unit of living organism. The science which deals with cells and their organelles is called cell-biology. The term cell was first used by Robert Hooke in 1665. He described the cell first as cella which means hollow space. Robert Hooke observed cells in the section of cork. In 1831 Robert Brown observed nucleus in plant cells. In 1858 Rudolf Virchow stated that new cells arise from pre-existing cells.

 

"Omnis cellulae cellula. Schilden, German Botanist in 1938 described cell theory with regard to plant cell. T. Schwann German Zoologist in 1939 described cell theory with regard to animal cells. Cell theory denotes that "Cell is the structural and functional unit of life."

 

 

The shape of the cells is variable. The cells of unicellular forms, leucocytes and-bacteria, exhibit a number of shapes and those of multicellular organisms exhibit still further variation. Their shapes may be rounded, cylindrical, irregular, triangular and tubular.

 

 

Size is extremely variable, measuring from one micron to 175 mm. The ostrich egg cell is 176 mm. in diameter, thus visible to the naked eye. The nerve cell found in mammals may reach a length of 3 or 3.5 feet. Smaller cells are those of the Pleuropneumonia like organisms.

 

 

A porous membrane surrounds the cytoplasm called plasma membrane. Electron microscopic studies reveal that the plasma membrane is composed of outer, inner protein layers and in between them double layered lipids are present Robertson called plasma membrane unit membrane.

 

The main function of plasma membrane is to regulate the entry and exist of substances.

 

 

The part of protoplasm outside the nucleus is known as cytoplasm. It is distinguished as an outer non-granular thick ectoplasm and inner granular thin endoplasm. In the cytoplasm many organelles are present.

 

 

In the cytoplasm many cell organelles are present.

 

 

It is the center of the cell discovered by van Benden in 1887. It is found near the nucleus and includes a specialised portion of cytoplasm, called centirosome. Its matrix is called as kinoplasm, in which two centrioles are embedded. Each centriole consists of nine fibrillar units and each fibrillar unit is found to contain three microtubules. The function of centrioles is to form the spindle at the time of cell division.

 

 

In the cytoplasm a network of tubules are present. It is called endoplasmic reticulum. This network of tubules will be two types.

 

 

On the surface of the tubules ribosomes are absent. Hence they are ce Sled smooth endoplasmic reticulum or agranular endoplasmic reticulum.

 

 

On the surface of the tubules ribosomes are present. It is rough endoplas­mic reticulum. This is called granular endoplasmic reticulum.

 

Endoplasmic reticulum will connect plasma-membrane nucleus and other organells.

 

 

 

 

It is a small particle present in the cytoplasm. They will be attached to the cell organelles and they are also freely distributed in the cytoplasm.

 

In a Eukaryotic cell 80s ribosomes are present. This ribosome is made by 2 sub units. They are 40s, 60s sub units.

 

Ribosome is made by proteins and RNA. Ribosome shows 150 to 200A° diameter. Ribosome combine with m RNA and produce proteins. A group of ribosomes with m RNA is called polysome.

 

 

They are described by Golgi. They are also called dictyosomes, Bpochondria, and idosomes. The complex shows three types of structures,

 

 

These are flat sacs. They are arranged one above the other. They are 150 V in length, 60 A° in thickness.

 

 

These are oval in shape. They are big.

 

 

They are in the form of groups. All these structures totally called Golgi complex.

 

 

They are more in secretory cells. Hence they are connected with secretory function. They store proteins and lipids. During cell division they produce cell, plate. During the formation of sperm they will form the acrosome of the sperm.

 

 

These are first described by Altamann as Bioplasts, in 1894. They were m i led as mitochondria by Benda in 1897.

 

They are filamentous or rod like structures. The mitochondria are covered by layers. Inner membrane is folded inside. Those folding's are called cristae. On these cristae oxysomes are present.

 

 

 

These are described by De-Duve. Each lysosome is round in shape. It shows .4 to .8 microns in diameter. It is covered by lipoprotein layer. It contains hydrolytic enzymes. It is useful for intracellular digestion and autolysis of the cell.

 

 

 

 

In the cytoplasm vacuoles and duetoplasmic bodies are pr-sent. In the young stages vacuoles are absent in the cytoplasm. When the cell is growing the .Cytoplasm vacuoles are formed. In a older cell big vacuole is present. It is filled with cell sap. A vacuole is covered by tonoplast. In the cell sap water, some excretory substances, some pigments, and other substances are present.

 

 

In the cytoplasm reserve food materials, excretory wastes a<\l secretory substances are stored. They are called duetoplasmic bodies.

 

 

In a eukaryotic cell a definite nucleus is present. It is 5 to 25 microns in, size. It shows the following parts.

 

 

Nucleus is covered by a nuclear membrane. It is made by 2 layers. In between the two layers perinuclear space is present. In the nuclear membrane small openings are present. Around each opening on the out side a small annulus is present.

 

Hammerling proved that nucleus is the seat of heredity through grafting experiments on Acetabularia.

 

 

Below the nuclear membrane nucleoplasm is present. In this glycoproteins, RNA and enzymes are present.

 

 

In the nuclear spa many chromosomes are present. They are thin and filamentous. They are in the form of a network. On the chromosomes genes are present. They are units of heredity.

 

 

In the nucleoplasm one or two round structures are present They are called nucleoli. They contain proteins and RNA. They produce ribosomes.

 

 

Cell Biology (Gr., kytos-hollow vessel or cell, logos-to discourse) is a biological science which deals with the study of cells. The cell itself can be regarded as the vital unit of organisms.

 

'Aristotle' and 'Paracelsus' concluded that "all animals and plants, how­ever, complicated are constituted by few elements which are repeated in each one of them."

 

The beginning of cell biology dates back to the 15th century, when 'Da Vinci in 1485 has stressed upon the use of lenses in viewing small objects. In 1658, 'Jan Swammerdam' gave the first description of the cell in his account of the red blood cells of the frog. The cytology came in its actual existence with the discovery of cell in 1665, by "Robert Hooke", while examining a thin slice of cork under his crude compound microscope, Hooke observed its honey-combed structure. He gave them the name "cells" (cellulae -little room).

 

Malphighi studied a variety of animal tissues microscopically and there­fore, he is generally considered as the father of 'microscopic anatomy '.

 

'A.V. Leeuwen Hoek (1632-1723) discovered the animalcules, infusoria (Protozoa), bacteria, etc., and made microscopical observations on protozoa, ants, aphids, spermatozoa, red blood cells etc.

 

The cell theory was proposed by two German biologists 'M.J. Schleiden' (1804-1881), and Theodor Schwann' (1810-1882) independently in 1838 and 1839, respectively. The cell theory holds that the animals and plants have same pattern of organization and construction. The bodies of both animals and plants are composed of cells and that each cell can act independently. In words of 'Schwann' and 'Schleiden' cell is "functional biological unit".

 

"Rudolf Virchow" in 1885 stated, "where a cell exists there must have been a pre-existing cell, just as the animal arises only from an animal and the plants only from a plant".

 

"Purkinje" in 1840 coined the term protoplasm. The protoplasm was first of all observed by "Corti" (1772) and the French Zoologist 'Dujardin' (1835) called it sarcode.

 

"Huxley" in 1868 referred to protoplasm as the "physical basis of life".

 

The protoplasm theory states that all living matter of animals and plants is protoplasm. The part of the protoplasm which occurs between the plasma membrane and nucleus is named as cytoplasm.

 

20th century brought many modern micro techniques. New histo chemical and cyto chemical methods have been developed to detect various molecular components of the cell. Different biochemical events of the cell could be known by autoradiography. Methods of tissue culturing have made possible the study of living cells.

 

Anatomy — It is a branch of biology which deals with the study of internal structure of an organism as revealed by dissection. 
Arthrology — Study of joints.
Agriology — Study of customs of primitive man.
Aphidology — Study of aphids (plant lice).
Aerobiology — Study of flying organisms in relation with other flying objects.
Agronomy — The management of farms and the science of crop production is called agronomy.
Anthropology — The science of man and mankind including his physical and mental constitution, cultural development and social conditions of present and past is called anthropology.
Anthology — It is a branch of biology study of flowers.
Agrostology — It is the study of grasses.
Acarology — Study of order acarina comprising ticks and mites.
Acrology — Study of ticks and mites is called acrology.

Aerobiology — Study of air borne organisms and structures such as spores etc. and their distribution.
Agriology — It is the comparative study of tribal customs.

Agrobiology — It is the quantitative science of plant life and plant nutrition.
Agrology — It is the soil sciecne dealing with production of crops.
Andrology — It is the study of male reproductive organs.

Araneology — It is the study of spiders.
Arboriculture — Cultivation of trees and shrubs is called arboriculture.
Agriculture — It deals with the cultivation of crops and the improved methods of farming.
Actinobiology — Study of radiation effect on living organisms.
Angiology — It is a biology branch Study of blood vessels.
Bionformatics — It is branch of science concerned with development and application of computing system and technology in order to make novel observation about biological processes.
Biotechnology — It is the controlled use of biological agents such as micro-organisms or cellular components for beneficial use.
Breeding biology — Breeding is art and science of changing and improving the heredity of plant and animals.
Biochemistry — Study of chemical aspect of living organims is termed biochemistry.

Bacteriology — Study of bacteria.
Batrachology — It is the study of frog.
Biocimatology — The study of climatic effects on biological processes and organisms.
Biometrology — Study of effects of atmospheric changes on living organisms.
Bionics — It is study of problem solving by humans, animals and its technical application.
Bacteriology — It is the study of bacteria.

Bryology — It is the study of bryophytes. Computational biology. Systematic development, application and validation of computational hardware solution for building simulation models of bilogical systems.

Cytology — It deals with the study of structure and functions of cell.
Cell Biology — The study of structure, functions, reproduction, energy dynamics, transport mechanism and life history of cell is called cell biology.
Cryobiology — It is the study of effect of low temperature on living organisms.
Chirology — It deals with communication system with deaf and mute by sign languages.
Chromatology — Study of pigments.
Ctetology — Study of acquired characters of organisms.
Chromatology — It is the science of colours.

Chronobiology — Study of biology of cyclic physiological phenomena.
Cosmology — Sciecne of structure and evolution of universe.

Cnidology — Study of coelenterates or Cnidarians Characteristics
Conchology — Study of shells.
Chondrology — Study of cartilage.
Craniology — Study of skull.
Cardiology — Study of heart.
Dysteleology — It is the study of appearance of vestigial organs due to evolution.
Dendrology — It is the study of shrubs and trees.

Developmental Biology — It deals with the study of processes by which organisms undergo progressive and orderly changes in structure as well as physiology during their entire life cycle.
Dermatology — Study of skin.
Developmental Morphology — It deals with the developmental aspects of plants.

Desmology — Study of structures and anatomy of ligaments.

Evolution — It is the branch of biology which deals with the study of descent of present day complex living organims (plants and animals) from the living forms of the past.
Embryology — It deals with the study of the stages of an organism that occur immediately after fertilization.
Ecology — It is the study of inter—relationship between living organisms and their environment.
Ethology — Study of animal behaviour and conditions of animals
Eugenics — It is the science dealing with the improvement of human race through application of the laws of heredity

Entomology — Study of insects.
Exobiology — The study of kind of life that may exist in outer space is called exobiology
Etiology — It is the study of causes of diseases.
Ecobiology — Study of adapations in relation to habitat.

Ecophysiology — Physiological adaptations in response to environment.
Epigenetics — It is the study of mechanisms by which genes and, their products bring about phenotypic expression.

Ethnobotany — It is the relationship between primitive humans and plants.
Ethnology — It is science dealing with different races of man kind.
Economic Botany — It deals with the study of various uses of plants and their products.
Environmental management — It is the assessment of environment, finding out the ways and means for remedy of environmental problems and for conservation of biodiversity so as to maintain the balance in nature. Forensic science — Application of science for identification of various facts about blood groups, hair, poisons, narcotics, finger prints, DNA finger printing for solving civilian and criminal cases.
Food technology — Study of processing and preservation of food is called food technology.
Forestry or silviculture — It deals with the development of forests and the utilization of their products.
Gynaecology — Study of female reproductive organs.
Gerontology — It is a branch of developmental biology which deals with the study of ageing.
Genetics — It is the study of genes heredity and variations.
Genecology — Study of genetical make up of species or population in relation to habitat.
Genetic engineering — The methods of artificial synthesis dna

Horticulture — It deals with the study of plants cultivated in gardens and orchards.
Hypnology — Science dealing with sleep including the one from hypnosis.
Helminthology — Study of parasitic worms.

Herpetology — Study of reptiles.
Hepatology — Study of liver.
Haematology — Study of blood.
Histology — The study of the structure and chemical composition of animal and plant tissue as related to the function.
heredity — It is the study of inheritance of characters from parents to offspring.
Ichthyology — Study of fishes or study of fishes and amphibians. 
Internal Morphology — It deals with the internal structure of plant parts and also called anatomy.
Ichnology — It is a branch of paleontology which deals with fossil foot prints.
Kalology — Study of human beauty.
Lepidepteriology — Study of butterflies and moths.

Limnology — Study of fresh water ecology.
Leprology — It is the study of leprosy its cause and cure.

Limnobiology — Its the study of fresh water.
Limnology — Study of fresh water ecology/study of snails.

Lichenology — It is the study of lichens.
Molecular Biology — Study of living organisms at the molecular level.
Morphology — It deals with the study of form and structure of animals.
Mammology — Study of mammals
Microbiology — Study of microscopic organisms.
Malariology — Study of malaria.
Myremecology — Study of ants is termed myremecology.
Malacology — Study of molluscs.
Myology (Sarcology) — Study of muscles.
Mastology — Study of breast including teats is called mastology.
Mycology — It is the study of fungi.
Neinatology — Study of nematodes (round worms).
Nephrology — Study of kidney.
Neonatalogy — It is science of study of new borns up to twenty eight days in humans.
Neurology — Study of nervous system.
Nidology — Study of nests of birds.
Ornithology — Study of birds.
Ophthalmology — Study of eyes.
Osteology — Study of bones
Organocology — Study of development of organs under embryology.
Olericulture — Its the branch of agriculture dealing with vegetables

Palaeozoology — It is the study of animal fossils.

Phenology — Study of organisms as affected by seasonal climates e.g. bird migration, opening of flowers etc.
Physiology — Study of functions of various parts of body is called physiology.
Parasitology — Study of parasites.
Protozoology — Study of unicellular organisms. i.e.Protozoa Characters 
Parazoology — Study of sponges.
Pathology — Nature, symptoms, causes, effects, prevention and suggestive cure of disease is called pathology.
Plant physiology — It is the study of various functional aspects or life processes of the plants.
Plant taxonomy — It is the study of identification, nomenclature and classification of plants.
Palaeobotany — It is the study of fossils of prehistoric plants.
Plant ecology — The study of relationship of plants with the environment is termed plant ecology.
Plant geography — The study of distribution of plants over the surface of earth.
Phycology — It is the study of algae.
Plant pathology — It is the study of plant diseases, their causes, symptoms and methods of control.
Pteridology — It is the study of pteridophytes.
Palynology — It is the study of pollen grains and sperms.

Pomology — It is the study of fruits.
Protology — It is the study of hind gut including rectum and anus.
Physiotherapy — Treatment of defects by physical remedies is called physiotherapy.
Protistology — It is the study of protists.
Phenology — Study of periodicity phenomenon of organisms e.g. Bird Migration.
Pharmacology — It is the study of medicine or drug plants.

Plant breeding — It is the study of genetics in relation to selective crossing and reproduction between different plants.

Plant agronomy — It is the science of soil management and production of crops.
Pharmacognsy — It is the scientific study of structural, physical, chemical and sensory characters of plants, cultivation, collection and other particulars relating to their uses.
Pharmacology — Study of synthesis and effect of medicines on organisms.
Phrenology — Study of mental faculties of brain including feelings.
Plant Morphology — Study of form and structure of plant organ is called morphology.

Rhinology — Study of nose and olfactory organs.
Serology — Study of serum ; interaction of antigens and antibodies in the blood.
Splanchnology — Study of visceral cavity and its organs.
Soil Science — The study of soil involving its structure, type and dynamics is called soil science.

Sedimentology — Study of rocks and fossils.
Space biology — It is the study of problem of survival living organisms in outer space.
Serpentology (Ophiology) — Study of snakes.
Saurology — Study of lizards.
Sitology — Science of food, diet and nutrition.
Stomatology — It is the study of foregut.
Speciology — Study of species.
Sarcology — It is branch of anatomy which deals with fleshy parts of body.
Spelaeology — Study of caves and cave life.
Teratology — lt is a branch of developmental biology which deals with the study of developmental abnormalities during embryonic stages.
Taxonomy — It deals with the principles of identification, nomenclature and classification of the animals.

Torentology — It is the study of diseases of embryo.

Taphonomy — It deals with the study of conditions conducive to fossilization of organisms in the plant.

Tricology — Study of hairs is called trichology.

Trophology — Study of nutrition is called tropology.

Toxicology — Study of narcotic effect on animals.

Therapeutics — Study of healing.
Tectology — It is the study of structural organization animals.
Traumatology — Study of injuries and wounds.

Urology — Study of excretory system.
Virology — It is the study of viruses.
Xenology — It is the study of hosts in relation to life history of parasites.
Zoogeography — It is the study of distribution of animals in different geographic regions.
Zoopathology — Study of diseases of animals.
Zoophytology — Study of drifting organisms such as diatoms.
Zymology — Study of fermentation is called zymology.

Zootechny — Science of breeding and domesticating animals.
Zoonosology — it is the study of handicapped animals.

Zoology — Study of Animals

Often called a “Digital Age Leonardo da Vinci”, Alexander Tsiaras is a digital innovator, technologist and artist. You might know him from his work that showcases beautiful digital images of the human body, made using cutting edge imaging software along with artsy tweaks. Guided by a passion for the human form and insides, Tsiaras founded the TheVisualMD, an extensive online library that documents human anatomy and illness, as well as Anatomical Travelogue, a company specialized in creating digital works of art that faithfully show the workings of the human body. He also authored a number of well received books like From Conception to Birth: A Life Unfolds, The Architecture and Design of Man and Woman: The Marvel of the Human Body, Revealed, The InVision Guide to a Healthy Heart and The InVision Guide to Sexual Health.

Read more: Breathtaking digital images probe human anatomy like never before