March 2019 | Biology Hubspot - Definition and Examples of Biology Terms

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Tuesday, March 19, 2019

Active Transport - Definition, Types and Examples

March 19, 2019 1
Hey! Do you want to know about what is  Active Transport its Types and Examples? Before drive in, we will first go through the insights of this article.

Active transport definition

Active transport is a process in which polar or charged solutes are transported across the membrane against the concentration gradient by using energy.

These solutes are unable to cross the membrane by any form of passive transport as they need to move against the concentration gradient, so they take the path of active transport.

The active transport due to its energy requiring factor for a carrier protein to move solutes against the concentration gradient it is considered an active process.

Sources of energy and their use
  •  1. The energy released in the hydrolysis of ATP is used in the primary active transport.
  • 2. The energy present in the ion concentration gradient is used in secondary active transport.

Primary active transport

Energy in the form of ATP is directly used in the transport of molecules across the membrane against the concentration gradient.

Example Na+/K+ pump.

Secondary active transport

Energy in other forms than ATP is used to transport molecules across the cell membrane. The energy stored in the ion concentration gradient is used in secondary active transport.

Example Na+/glucose co-transporters.

The two processes viz. endocytosis and exocytosis accomplish the process of active transport.

In exocytosis, the materials are moved out of the cell by fusing them with the plasma membrane of vesicles inside the cell.

In exocytosis opposite of the endocytosis takes place as the materials are moved into the cell.

Types of active transport

Antiport pumps

Antiport pumps are used in the transport of two or more different molecules in the opposite direction.

Due to the use of only one ATP in doing these two separate tasks the antiport pumps are considered as extremely efficient pumps.

The important example of the antiport pump is the
 Sodium-potassium pump, which we will discuss in detail under the headline Examples of Active transport.

Symport pumps

In symport pumps, the molecules are transported via diffusion gradient from the areas of higher concentration to the areas of lower concentration.

In the symport pump, the molecules or substances that move from an area of higher concentration to an area of lower concentration also carries another substance or molecule with it against the concentration gradient.

The important example of symport pump is the sodium glucose transport protein that is described in detail under headline examples of active transport.

Endocytosis

The endocytosis is that type of active transport in which large substances or we can say a large amount of ECF or extracellular fluid is drawn into the cell.

The process of endocytosis is of three types
  • Receptor-mediated endocytosis
  • Phagocytosis
  • Bulk-phase endocytosis

Receptor-mediated endocytosis

Being the highly selective type of endocytosis this process is used by the cell in taking up of specific ligands.

The specific ligands that are transported via receptor-mediated endocytosis include LDLs, transferrin, some vitamins, antibodies, and certain hormones.

Phagocytosis

Is that type of endocytosis in which cell engulfs large solid particles such as worn-out cells, whole bacteria or viruses

The cells called phagocytes are only cells in the body that have the ability to perform the process phagocytosis.

Examples of phagocytic cells in the body are neutrophils and macrophages.

Bulk phase endocytosis

It is also known as pinocytosis in this type of endocytosis the tiny droplets of extracellular fluid are taken up.
The process of bulk-phase endocytosis takes especially in the cells involved in the process of absorption example absorptive cells of kidney and liver.

Exocytosis

This process being opposite to endocytosis is used to carry materials out of the cell by the formation of vesicles inside the cell.

The cell uses exocytosis to transport substances like hormones, antibodies, and enzymes formed within the cells to the sites in the body where these substances are needed.

The proteins formed in the endoplasmic reticulum are ultimately moved into the Golgi complex of the cell. The Golgi complex consists of various sac-like structures called cisternae that give it a cup-like shape.

The Golgi complex packages and processes the products and fuses with the cell membrane. As the vesicles become part of the cell membrane they pour the processed products into the extracellular space.

EXAMPLES OF ACTIVE TRANSPORT

Sodium-potassium pump

The sodium-potassium pump is an important active transport pump that is used to move sodium and potassium in the opposite direction against their concentration gradient into and out of the cell.

This task of moving ions in and out of the cells seems to be a very simple task but it consumes about 20-25% of energy generated from the food.

The nerve cells generate nerve impulses due to the concentration difference between inside and outside of the nerve cell.

In addition to this, the ion concentration gradient is involved in doing various physiological activities such as muscle contraction, sensations and even contraction of heart muscle etc.

Sodium-Glucose transport protein

Sodium-glucose transport protein is an important example of a symport pump which binds to 2 Na+ ions and 1 glucose ion. The former wants to move into the cell while as latter wants to stay outside of the cell.

In this way, the glucose is carried into the cell without the expenditure of ATP. However, ATP is utilized by the sodium-potassium pump in keeping up the sodium gradient so that the sodium glucose transport protein can function properly.

White blood cells attacking bacteria

The white blood cells or leucocytes engulfing pathogens in the body is an important example of endocytosis.

The white blood cells have the ability to recognize the foreign harmful bodies that are usually not present in the body which may be bacteria, after recognizing the foreign body it is bounded and then taken into the cytoplasm.

After entering into the cytoplasm is then subjected to lysosome which contains powerful chemicals and enzymes to digest and breakdown the organic matter. In this way, the white blood cells digest the foreign invader.

This was all about  Active Transport - Definition, Types and Examples from myself. I hope you will like this article and don't forget to share it !...

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Thursday, March 7, 2019

Modifications of roots and stems

March 07, 2019 0

Modifications of roots and stem

  •  Modifications of roots.
  • Modifications of the Tap roots.
  • Modifications of Adventitious Roots.
  • Modifications of roots on the basis of mechanical strength.
  • Modifications of roots on the basis of vital functions.
  • Modifications of the stem.

Modifications of roots 

 ๐Ÿ’™ Roots generally perform the function of absorption and conduction of water and minerals in plants.
๐Ÿ’™ But uncertain conditions they undergo modification and perform functions other than the primary functions like storage, support, and respiration.

Modifications of Tap Roots

 a) Conical: upper part bulged and the lower part shows gradual tapering example Daucus Carota.

 b) Napiform upper part bulged but lower part shows abrupt tapering examples Brassica rapa ( turnip), Beta vulgaris ( chukandar).

c) Fusiform: Found upper and lower parts are tapering but the middle part is swollen. example Raphanus sativus (Raddish).
d) Tuberous: No definite shape as their is irregular buldging and tapering e.g. Mirabilis Jalapa (4 clock plant), Trichosanthes.

Modifications of Adventitious Root

 a) Moniliform:  Swollen alternatively to give a beaded appearance, thus also called beaded roots examples Vitis Vinifera (grapes), Sorghum, Dioscorea

 b) Tuberous Upper Irregularly swollen or bulged also known as storage roots example Ipomoea batatas (Sweet potato).

c) Fasciculated:  Cluster of rootlets swollen from top to bottom examples Asparagus, Dahlia.
d) Nodulose:  Tip of the root is bulged example Curcuma Amada (Haldi).
b) Annulated:- Most Root appears like a rope as it is formed of a number of discs placed one over other examples Ipecac.
 Modifications of roots on the basis of Mechanical Strength.
a Prop or Pillar roots: Arise from aerial branches go downwards and provide support examples Ficus Benghalesis, Pandanus.
⚈ IBG Kolkata is famous for Banyan trees i.e Ficus Bengalensis.

 bStilt roots upper Arise from the node present very close to the soil surface and provide mechanical support examples Zea Mays, Sorghum, Bajra, Saccharum Officinarum.

cRoot buttresses: Horizontal running roots arising from the base of the stem to provide support examples Rubber tree ( Ficus elastica).
dClimbing roots or Clinging rootsIn certain climbers having the weak stem, roots arise from the node and clasp around the support and thus helps in climbing examples Piper betle, Pathos (Money plant), Campsis etc..

dAdhesive rootsIn plants like ficus rapens , Hadera helix roots adhere to the support on account of their adhesive nature(adhesive discs).

Modifications of roots  on the basis of Vital Functions

a Pneumatophores: Knee or breathing or respiratory roots, come out of the soil and bear minute pores called as pneumatophores to carry out respiratory exchange of gases examples Mangrove plants like Rhizophora, Avicennia, Sonneratia etc.

 bNodulated Roots Such roots have spherical outgrowths called as nodules which contain Nitrogen-fixing bacteria examples Leguminous plants (pea).

cParasitic Roots:   Also called as sucking or Haustorial roots are used to absorb food and water from the host plant example Cuscuta.

dFloating Roots  Produced by aquatic plants, come out on the water surface to provide buoyancy and also carry out respiratory exchange of gases examples Utricularia, Jussiaea etc.
eContractile or Pulling Roots:  Such roots contract to bring corms in an appropriate position examples Saffron (crocus sativus belong to family Iridaceae), Allium Sepa (Onion).

fEpiphytic Roots:  Also called as sucking or Haustorial roots are used to absorb food and water from the host plant examples Cuscuta.


Modifications of the stem.
aStem Tendrils:  Slender, spirally coiled develop from axillary buds and help plants to climb examples Passiflora, Luffa, Cucurbita, Grape Vine etc.

 bStem Thorns  Woody, straight pointed structures which also develop from axillary buds and help in reducing transpiration, in addition, protect plants from browsing animals examples  Citrus, Bougainvillea, Hugonia etc.

cPhylloclades  Stem modified into flattened (Opuntia), or fleshy cylindrical (Euphorbia) structures that contain chlorophyll and perform photosynthesis.

dCladodes Green photosynthetic stems  with leaves modified reduced to scales or modified into spines examples  Ruscus, Asparagus etc 
This was all about the Modifications of roots and stems. I hope you will like this article and don't forget to share it !...
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Sunday, March 3, 2019

Biology Hubspot | Biology So Easy

March 03, 2019 0

Biology HubSpot | Biology So Easy

Biology HubSpot: Biology HubSpot is a standard blog useful for all Biology students and teachers. In biology HubSpot, you will get to the point material of biology. 
 Below are our social media sharing platforms, on which you can follow us and remain in connection with daily published articles.                          

About Founder of Biology HubSpot | Biology So Easy

Musaib Manzoor

Hii, my name is Musaib Manzoor. I am 19 years old BSc student(&blogger) of SKIMS very much interested in blogging. I started this site to write articles about my most passionate subject so that I can help others even myself by learning new information on a daily basis.

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Saturday, March 2, 2019

Permanent tissue: Types and Functions of simple permanent tissue

March 02, 2019 0

Permanent tissue: characteristics, types, and functions

 ๐Ÿ’™ Consists of cells which have lost the power of division temporarily or permanently.

๐Ÿ’™ Formed by differentiation of meristematic tissues.
๐Ÿ’™ Maybe living or dead.
๐Ÿ’™ Cells of permanent tissue are arrested at the Go or G1 stage of the cell cycle.
๐Ÿ’™ Made up of mature cells.

Types of permanent tissue


        ➤ Simple permanent tissue or homogenous tissue.

        ➤ Complex permanent tissue or Heterogenous tissue.
        ➤ Special tissue or Secretory tissue.

Simple permanent tissue or Homogenous tissue


Simple permanent tissue is made up of structurally similar types of cells that perform a common function.

⚈ Simple permanent tissue is of the following 3 types.

        1) Parenchyma

        2) Collenchyma

        3) Sclerenchyma


Parenchyma
⚈ Very primitive and first evolved tissue.

⚈ All other tissues are derived from parenchyma, so it is also known as fundamental tissue or precursor of all other tissues.

⚈ Termed by N. Grew.
⚈ Present in almost all the parts of a plant like a root, stem, leaves etc and is thus a universal tissue.
⚈ Living tissue.
⚈ First differentiated tissue.
⚈ Living tissue.

⚈ The pulp of fruits and body of bryophytes mainly contains parenchyma.

⚈ Living storage tissue of thin pectocellulosic cell wall i.e. pectin and cellulose.
⚈ Each cell has a large central vacuole and thus associated with the storage of food.

⚈ No or small intercellular spaces. [Spaces if present is schizogenous in origin.]
⚈ The most common tissue and is morphologically as well as physiologically unspecialized.
⚈ Cells are isodiametric.
⚈ Parenchymatous cells are spherical, oval and polyhedral in shape.
⚈ Found in the cortex, pericycle, mesophyll of leaf, floral parts, pith, medullary rays etc.
⚈ Each cell has a large central vacuole and thus associated with the storage of food.

Modifications of parenchymatous tissue

 a) Prosenchyma: Fibre-like elongated, pointed and thickly walled parenchyma is prosenchyma. It provides mechanical support and is present in the pericycle of the root.

 b) Aerenchyma: Made up of round or spherical cells that surround large air chambers. Found in the cortex region of hydrophytes and thus provides buoyancy to them.
c) Chlorenchyma: Found in the mesophyll of leaf and contains abundant chloroplasts and thus performs photosynthesis.
d) Stellate parenchyma: Contains star-shaped cells, found in the leaf base (pseudostem) and petiole of banana leaves to provide mechanical support to them.
 e) Mucilage parenchyma: Large vacuoles and mucilage are present just to bring water storage.Found in the succulent plant like Aloe, opuntia, Euphorbia etc
Functions of Parenchyma
⚈ Some parenchymatous cells store waste materials called idioblasts.
The idioblasts store tannins, oils, calcium oxalate crystals etc.

⚈ As chlorenchyma, it performs photosynthesis.

⚈ As Aerenchyma provides buoyancy to hydrophytes.
⚈ As prosenchyma, stellate parenchyma it provides mechanical support.
⚈ As mucilage parenchyma stores water.
⚈ Secrete many substances like enzymes, resins, nectar, oils etc..

 Collenchyma

⚈ Living mechanical tissue.

⚈ Termed by Schleiden.
⚈ More or less elongated thin-walled cells but thick at corners
(thickening=pectin(mainly)+ cellulose+ Hemicellulose).
⚈ No intercellular spaces.
⚈ Generally, contain chloroplasts.
⚈ Usually present in Hydrophytes of dicot stem, leaf margins, petiole of a leaf, the pedicle of flowers etc.

⚈ Absent in woody parts of the plant [ showing secondary growth roots (except aerial roots of monestra , monocot stem].

⚈ Contain a vacuolated cytoplasm.
 Types of collenchyma

 a) Lamellar or Plate collenchyma:- cells arranged in lamellar form and have thickenings or tangential walls e.g sunflower stem.

b) Angular collenchyma:- Most common type and the deposition occurs at angles or corners of the cell wall e.g. Stem of Datura, Solanum, tomato.
 c) Lacunar or Tubular collenchyma:- Large intercellular spaces are present in this type and deposition occurs on the walls lying towards intercellular space.

 Functions of collenchyma

 ⚈ It provides mechanical support to the growing parts of the plant.

 ⚈ It also performs photosynthesis as it contains chloroplasts.
 ⚈ Being present at leaf margins prevents them from tearing.

 Sclerenchyma
 ⚈ Dead mechanical tissue

⚈ Termed by Mettenius.
⚈ Long, narrow thick walled lignified but without protoplast and thus dead.

⚈ Found in the hypodermis of the monocot stem.
⚈ Pits are present on lignified walls.
 Types of Sclerenchyma
 1) Sclereids:- small, extremely thick walled irregular isodiametric but their ends are not pointed. Sclereids have very narrow lumen but a number of pits.

Found in walls of nuts, pulp of Guava, Sapota (cheeku), seed coat of legumes, leaves of tea etc.

Term Sclereid was given by Tscherch

On the basis of morphology, Tscherch classified sclereid into following types
 a) Brachyscleroids or stone cells or Gritt cells:- small, spherical, roughly isodiametric sclereids found in endocarp of drup fruits, coconut,pulm etc
 b) Osteosclereids or bone cells or prop cells:- pillar like cells whose ends spread to form a bone-like structure e.g leaves of Hakea, Osmanthus, Seed coat of
monocots.
 c) Macrosclereids or rod cells or Malphigi cells:- Rod-shaped sclereids found in
seed coats and sometimes induce dormancy. 
Hardest seed coat among legumes is in French Bean.
The hardest seed coat among all plants is in Lotus.
 dAsterosclereids:- star-shaped cells found in leaves of floating hydrophytes e.g  Victoria, Nelumbo, Nymphaea.
 e) Trichosclereids:- just like asterosclereids are found in floating leaves of hydrophytes but are spine like cells rather than star-shaped i.e why also
 called as internal hairs.
2) Sclerenchymatous Fibres:- Longest cells in plant body Thick walled cells with pointed ends and reduced lumen. Great tensile strength, flexibility, the elasticity of fibers enables the plant to withstand a variety of strains and tension.

Fibres contain both simple as wells as bordered pits. 

Sclerenchymatous fibres are of two types
a) Libriform fibres:- Highly thickened long fibres with simple pits and narrow lumen e.g phloem, pericycle, hypodermis fibres.
 b) Tracheidal fibres:- Thickened long fibres with simple as well as bordered pits but slightly broad lumen e.g xylem fibres.

This was all about the types and functions of permanent tissue. I hope you will like this article and don't forget to share it !...
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