Archive for the ‘Examination’ Category

Structure of GATE

Examination Type

The GATE examination consists of a single paper of 3 hours duration, which contains 60 questions carrying a
maximum of 100 marks. The question paper will consist of only multiple choice objective questions. Each question
will have four choices for the answer. Only one choice will be correct. Candidates have to mark the correct choice
on an Optical Response Sheet (ORS) by darkening the appropriate bubble against each question. There will be
1/3 rd deduction for each wrong answers

CSIR-UGC National Eligibility Test (NET) for Junior Research Fellowship and Lecturer-ship

REVISED SYLLABUS

EFFECTIVE DECEMBER 2008 EXAMINATION

SYLLABUS FOR LIFE SCIENCES PAPER I AND PAPER II

Unit 10. ECOLOGICAL PRINCIPLES
A. The Environment: Physical environment; biotic environment; biotic and abiotic interactions.
B. Habitat and niche: Concept of habitat and niche; niche width and overlap; fundamental and realized niche; resource partitioning; character displacement.
C. Population ecology: Characteristics of a population; population growth curves; population regulation; life history strategies (r and K selection); concept of metapopulation – demes and dispersal, interdemic extinctions, age structured populations.
D. Species interactions: Types of interactions, interspecific competition, herbivory, carnivory, pollination, symbiosis.
E. Community ecology: Nature of communities; community structure and attributes; levels of species diversity and its measurement; edges and ecotones.
F. Ecological succession: Types; mechanisms; changes involved in succession; concept of climax.
G. Ecosystem: Structure and function; energy flow and mineral cycling (CNP); primary production and decomposition; structure and function of some Indian ecosystems: terrestrial (forest, grassland) and aquatic (fresh water, marine, eustarine).
H. Biogeography: Major terrestrial biomes; theory of island biogeography; biogeographical zones of India.
I. Applied ecology: Environmental pollution; global environmental change; biodiversity-status, monitoring and documentation; major drivers of biodiversity change; biodiversity management approaches.
J. Conservation biology: Principles of conservation, major approaches to management, Indian case studies on conservation/management strategy (Project Tiger, Biosphere reserves).

There are two types of cells: eukaryotic and prokaryotic. Prokaryotic cells are usually independent, while eukaryotic cells are often found in multicellular organisms.

Eukaryotic cells

Eukaryotic cells are about 10 times the size of a typical prokaryote and can be as much as 1000 times greater in volume. The major difference between prokaryotes and eukaryotes is that eukaryotic cells contain membrane-bound compartments in which specific metabolic activities take place. Most important among these is the presence of a cell nucleus, a membrane-delineated compartment that houses the eukaryotic cell’s DNA. It is this nucleus that gives the eukaryote its name, which means “true nucleus”. Other differences include:

• The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup. Cell walls may or may not be present.
• The eukaryotic DNA is organized in one or more linear molecules, called chromosomes, which are associated with histone proteins. All chromosomal DNA is stored in the cell nucleus, separated from the cytoplasm by a membrane. Some eukaryotic organelles also contain some DNA.
• Eukaryotes can move using cilia or flagella. The flagella are more complex than those of prokaryotes.

Prokaryotic cells

Prokaryotes differ from eukaryotes since they lack of a nuclear membrane and a cell nucleus. Prokaryotes also lack most of the intracellular organelles and structures that are seen in eukaryotic cells. There are

two kinds of prokaryotes, bacteria and archaea, but these are similar in the overall structures of their cells. Most functions of organelles, such as mitochondria, chloroplasts, and the Golgi apparatus, are taken over by the prokaryotic cell’s plasma membrane. Prokaryotic cells have three architectural regions: appendages called flagella — proteins attached to the cell surface; a and pilicell envelope – consisting of a capsule, a cell wall, and a plasma membrane; and a cytoplasmic region that contains the cell genome (DNA) and ribosomes and various sorts of inclusions. Other differences include:

• The plasma membrane (a phospholipid bilayer) separates the interior of the cell from its environment and serves as a filter and communications beacon.
• Most prokaryotes have a cell wall (some exceptions are Mycoplasma (bacteria) and Thermoplasma (archaea)). This wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces. It also prevents the cell from “exploding” (cytolysis) from osmotic pressure against a hypotonic environment. A cell wall is also present in some eukaryotes like plants (cellulose) and fungi, but has a different chemical composition.
• A prokaryotic chromosome is usually a circular molecule (an exception is that of the bacterium Borrelia burgdorferi, which causes Lyme disease). Even without a real nucleus, the DNA is condensed in a nucleoid. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular. Plasmids can carry additional functions, such as antibiotic resistance.

Souce : wikipedia