Download Agrobacterium tumefaciens

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INSTANT NOTES FOR AIPMT MAINS
Agrobacterium tumefaciens
It has the ability to transfer and stably integrate foreign DNA into plant genome. Nif genes are tied to
T1 plasmid and is allowed to integrate into genome of non-leguminous plants.
Azospirillum lipoferum
Nitrogen fixing bacteria present in the roots of Brazilian grasses and Maize. Scientists are trying to
associate Azospirillum with cereals to reduce the use of chemical pesticides.
Penicillin
Antibiotic obtained from Penicillium notatum and Penicillium chrysogenum. Penicillin is a broad
spectrum antibiotic. It prevents wall formation in bacteria and kill them.
Aspergillus niger
It is used in commercial preparation of citric acid from sugarbeet and sugarcane molasses. It can
convert 40% of sucrose to citric acid.
Embryo rescue technique
Technique used to prevent the death of hybrid embryos. The technique involves excision and growth
of hybrid embryo in a culture on a nutrient medium. It helps to produce hybrids that are disease
resistant.
Adaptive radiation
A phenomenon in evolution. It is the emergence of numerous species from a common ancestor
introduced into an environment presenting a diversity of new oppertunities and problems.
Allosteric site
It is a specific site on the enzyme molecule. It is different from the active site. Molecule that binds to
the allosteric site change the shape of the active site making the enzyme either more or less receptive
to the substrate.
Alpha diversity
It is defined as the diversity of organisms sharing the same community or habitat. A combination of
species richness and evenness is used to represent alpha diversity.
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Alpha helix
It represents the coiling form of polypeptide. The spiral shape of the protein is due to alpha helix
coiling. Alpha helix is due to the formation of hydrogen bonds.
Amphidiploid
It is a tetraploid individual having 2 sets of chromosomes derived from two species. It is a form of
allotetraploid.
Apical dominance
It occurs during plant growth. Concentration of growth occurs at the tip of the shoot and the terminal
bud partially inhibit the growth of axillary bud.
Autoradiography
It is the method used to localize radioactive atoms in microscopic preparations of biological materials
by exposing a photographic film emulsion to radioactive atoms incorporated in the biological
specimen.
BAC
Bacterial Artificial Chromosome. It consists of F plasmid of bacteria and can be used for transferring
eukaryotic genes.
Balanced polymorphism
It is a type of polymorphism in which the frequencies of the coexisting forms do not change
noticeably over many generations.
Bacillus thuringienesis
It is the soil bacterium produces a crystal protein called Cry protein in its spores which is toxic to
larvae of certain insects. The gene encoding Cry protein is called cry gene and has been isolated and
efforts are being made by scientists to transfer this gene into Chick pea and other pulses to ptotect
them from severe damaged caused by insect pests.
Biopatency
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Patency is a right given officially to an inventor to make or sell his/her invention and to prevent
others from copying it. Countries like USA, Japan and European union award biopatency for strains
of microorganisms, cell lines, genetically modified plants and animals, DNA sequences,
biotechnology products, procedures etc.
Biopiracy
It is the unauthorized use of patent resources by organizations and multinational companies of other
nations. For example, the patent claimed by USA for the Basmati rice whose germplasm originally
belong to India. The protein Brazzein from West African plant Pentadipiandra brazeana which is a
low calorie sweetner has been patented in the USA.
Biowar
This involves the use of biological weapons against humans, crops and animals. Biological warfare
involves bioweapon agents or toxins which attack humans, crops and animals and its use in war has
been dated back to 5th century B.C. Bioweapon agents are contained in the containers and delivered
as powders, sprays etc. Some of the potent pathogens used in biowarfare are Anthrax, Small pox,
Botulinum pathogens.
Bioethics
It involves the set of standards that are used to regulate and monitor our activities in relation to
biological world. Biotechnology has greatly exploited the biological world and there are several
bioethical concerns which include over use, disrespect given to plants and animals and also the risk
involved in the experiments.
Biological magnification
It is a trophic process in which retained substances become more concentrated with each link in the
food chain.
Bioremediation
It is the use of microorganisms for the removal of pollutants.
Blood-Brain barrier
This is a specialized capillary arrangement in the brain that restricts the passage of most substances
into the brain, thereby preventing dramatic fluctuations in the brain’s environment.
Biological Oxygen Demand
It is the quantitative expression of the oxygen depleting impact. It is an expression of how much
oxygen is needed for microorganisms to oxidize their organic matter.
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Bottle neck effect
Genetic drift resulting from reduction of a population, typically by natural disaster, such that the
surviving population is no longer genetically representative of the original population.
c-DNA
It is a duplex DNA complementary to m RNA synthesized from it by reverse transcription. It lacks
introns because there is no introns in m RNA. C DNA is called complementary DNA.
Cell mediated immunity
The type of immunity that functions in defense against fungi, protests, bacteria and viruses in side
host cells and against tissue transplants with highly specialized cells that circulate in the blood and
lymphoid tissues.
Chaparrel
A scrub land biome of dense, spiny, evergreen shrubs found along coasts where cold ocean currents
circulate off shore, characterized by mild, rainy winters and long, hot, dry summers.
Chemiosmosis
The ability of certain membranes to use chemical energy to pump hydrogen ions and then harness
the energy stored in the Hydrogen ion gradient to drive cellular work including ATP synthesis.
Co factor
Any non-protein molecule or ion that is required for the proper functioning of an enzyme. Co factors
can be permanently bound to the active site or may bind loosely with the substrate during catalysis
Competitive exclusion principle
The concept that when the populations of two species compete for the same limited resources, one
population will use the resources more efficiently and have a reproductive advantage that will
eventually lead to the elimination of the other population.
Complement system
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A group of atleast 20 blood proteins that cooperate with other defense mechanisms, may amplify the
inflammatory response, enhance phagocytosis or directly lyse pathogens; activated by the onset of
the immune response or by surface chemicals on microorganisms.
Convergent evolution
The independent development of similarities between species as a result of their having similar
ecological roles and selection process.
Corpus luteum
Secreting tissue in the ovary that formed from the collapsed follicle after ovulation and produces
progesterone.
Counter current exchange
The opposite flow of adjacent fluids that maximizes transfer rates. For example, blood in the gills
flows in the opposite direction in which water passes over the gills, maximizing oxygen uptake and
carbon dioxide loss.
Double Bohr effect
Foetal hemoglobin takes oxygen from mother hemoglobin through the placenta due to double bohr
effect. Foetal hemoglobin dissociation curve shifts to left. Foetal hemoglobin is a tetramer having two
alpha chains and two gamma chains. So HbF is insensitive to a shift due to 2-3 DPG and the curve is
Sigmoid.
Oxygen dissociation curve
It is a graph that shows the percent saturation of hemoglobin at various partial pressures of oxygen.
Commonly a curve may be expressed with P50 value. This value represents the pressure at which the
erythrocytes are fifty percent saturated with oxygen. The purpose of the oxygen dissociation curve is
to show the equilibrium of oxyhemoglobin and non- bonded hemoglobin.
Surfactant
It is a lipid surface tension lowering agent present in the lining of alveoli. It is a mixture of
Dipalmitoyl Phosphotidyl Choline ( DPPC ) , other lipids and proteins secreted by the type II alveolar
epithelial cells. Surfactant reduces the surface tension in the fluid on the surface of alveoli, allowing
them to expand at first breath and remain open there after.
2-3 DPG
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2-3 Diphospho glycerate is a highly anionic organic phosphate created in the RBC, during glycolysis.
It binds to hemoglobin and reduces the oxygen affinity. This is essential to unload oxygen in the
tissue capillaries. In the absence of DPG, body makes more RBC. The RBC membrane become weak
and RBC become irregularly shaped and hemolyse.
Gene bank
Gene bank or Gene library is the collection of cloned genes, frequently comprising cells of the gene
from a particular species. Such libraries may consists of genomic sequences or DNA sequences, the
latter having being made from messenger RNA and intron sequences.
Transgenic organisms
Organisms that has become transformed following the introduction of new DNA into its genome is
called transgenic organism. Transgenic crop plants contain a gene or genes which have been
artificially inserted instead of plant acquiring them through pollination. The inserted gene sequence
is called Transgene may come from another unrelated plant or from a completely different species.
For example, Bt Corn with gene from Bacillus thuringienesis, resistant to over ripening of Tomato.
Transgenic animals have novel genes obtained from outside. For example, Plasminogen activator in
milk ( Goat ). Transgenic microbes are being used in industry for producing different bio chemicals
and various functions. For example, Pseudomonas putida has been changed by introducing Plasmids
of different strains for Alcoholic fermentation.
Bt Cotton, a transgenic crop variety, have been introduced in India. The Bt cotton variety contains a
foreign gene obtained from Bacillus thuringienesis. This bacterial gene, introduced genetically into
the cotton seeds protect the plant from Bollworm, a major pest of cotton. Bt cotton requires only 2
sprays of pesticide while the normal variety requires 8 sprays. According to Indian Council of
Agricultural Research ( ICAR ), India uses about half of its pesticides on cotton to fight against
Bollworm menacle. Use of Bt cotton has led to a 3% - 27% increase in cotton yield in countries where
it is grown
Gene transfer techniques
Used to transfer genes from one organism to another
1. Agrobacterium mediated gene transfer
2. Direct gene transfer using Biolistic gun, Electroporation , Microinjection etc.
Trangenic plants
The plants which carry additional stably integrated and expressed foreign genes transferred from
other genetic sources are called as transgenic plants.
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Agrobacterium mediated transfer
The most common techniques used to transfer genes to Dicotyledonous plants using Agrobacterium.
Cereals are difficult to transform through Agrobacterium because they do not have the proper
wound response, a necessary requirement for transformation.
Transgenic vegetables
First transgenic plant
Flavr Savr- delayed ripening tomato – introduced by Calgene Inc. USA in
1994.
Cherry, Endless summer ( tomato ) – contains Bt protein gene against fruit borer.
Freedom II
Squash resistant to water melon mosaic virus
New leaf ( Potato )
resistant to Colorado beetle ( Leptinotarsa decemlineata )
AmAl
Amaranth
Parthenocarpy fruits
Seed less fruits
Golden rice
With high Vit. A content
Biological magnification
It is the process where by certain substances such as pesticides or heavy metals move up the food
chain, toxins build up a successive link of the food chain. It works their way into river or lakes and
are eaten by aquatic organisms such as fish which in turn are eaten by large birds, animals or
humans. The substance become concentrated in the chain. It is like a magnifying glass that makes
things look bigger. Biological magnification makes toxin get bigger and stronger in the ecosystem.
Eg. 1 Some pesticides are considered as Environmental Oestrogens. These chemicals interfere with
sex hormones and causes decreases sperm counting, breast cancer, testicular cancer, mis carriage etc.
Methoxyclor, Atrazine, Benomyl are examples.
Eg. 2 Beetals may have very low level of fat soluble pesticides, but the pesticides will build much
greater levels till in a human that eats the beetal eating bird.
Eg. 3 DDT in food chain of coastal water of long island.
Genetic map or Linkage map
These are maps based on the recombination frequency. It includes determination of linkage groups
and determination of map distance. A linkage group does not show the physical distance between
genes but rather their relative positions as determined by how gene loci are inherited together. The
closer two genes are, the more often they will be inherited together. Linkage distance is measured in
Centimorgan unit ( cM)
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Chromosome map
These are used to identify the location of genes using special cytological techniques such as
Chromosome Banding.
Bio-informatics
This is a new computer aided technology to store, retrieve, analyze or predict the composition or
structure of bio-molecules. Classical bio-informatics mainly deal with the sequence analysis of DNA
or Protein. The Human Genome Project is currently being completed with the help of Bio-informatics.
New Bio-informatics include Medical imaging or Image analysis, biologically inspired computation
like Genetic Algorithms.
Pesticides
Organochlorides
DDT, BHC, Aldrin, Endosulphan – These are lipophilic compounds accumulate
In fat depots like liver.
Organophosphates Malathion, Parathion, Feritrothion- These affect nervous system.
Carbamates
Carbaryl, Carbofuran
- Inhibit Acetylcholine esterase.
Highly toxic pesticides
Well known pesticide
Insecticide for Malaria control
Furudan
Baygon
DDT, BHC, Carbofuran, Aldrin
Parathion
Malathion
It is Carbofuron
It is Propoxus
Herbicides destroy the weeds by affecting the Photosystem II.
Pesticide Thread Mill
More expensive and more poisonous pesticides used to obtain
target. Eg. Pesticides for Cotton in India.
Biopesticides
These are biological agents used to control pests. Devine and Colego first used Fungal spores in weed
control.
Confusion technique of pest control uses Pheromones. It is used in IPM.
Ecdysone, JH etc are insect hormones used to control pests in IPM.
Pyrethrum is obtained from Chysanthemum cineranifolium is a natural plant insecticide. It is used
to make Mosquito coils.
Neem contains an Anti-feedant called Azadiraclitin.
Food crops
Barley, Cotton, Sorghum
Ethiopia
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Maize
Sunflower
Pineapple, Rubber
Tomato, Potato
Mexico, Central America
USA
Brazil
Aeruvian Andes
Sugar cane breeding institute is located in Coimbatore
Orthodox seeds
These are seeds withstand low moisture and low temperature. Egs. Cereals, Legumes.
Recalcitrant seeds
These are seeds killed by drying and freezing. Egs. Jack fruit, Tea, Cocoa, Rubber, Palm.
Domestication of Animals
Indian cows are cross bred with European breeds like Holstein, Brown swiss, Jersey, Red / Dane.
Karan swiss and Sunandini are breeds developed through cross breeding at National Dairy Research
Institute Karnal and Kerala.
Zebu cattles are resistant to Rinderpest or Cattle plague, Foot and Mouth diseases.
Exotic breeds of sheep are Dorset, Horn and Merino.
Breeds of Indian cattle
Miltch breed
Gir ( Rajastan ), Sahiwal ( Punjab, Haryana, U.P ), Red sindhi ( A.P )
Draught breeds
Malvi ( Rajastan, M.P ), Nageri ( Delhi, Haryana, U.P ), Hallikar ( Karnataka )
General breeds
Ongole ( A.P ), Kankref ( Gujarat ), Tharparkar ( A.P, Gujarat )
Sheep
Nellore ( Maharashtra )
Poultry exotic breeds
White leghorn, Rhode Island Rod, Plymouth Rock, New Hampshire.
Fishery
Bombay duck
Sericulture
Tasar silk
Mulberry silk worm
Harpodon. Marine form
Antherea roylei ( non mulberry )
Bombyx mori
Interspecific hybridization
Male and females of two different species are mated. The progeny obtained from such a mating are
usually different from both the parental species. Mule is produced from a cross between female horse
( Mare ) and male donkey. Mules are sterile, sturdier and hardier than their parental species.
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HIV infection
HIV causes AIDS, which attaches to a receptor called CD4. This receptor is present in the plasma
membrane of WBC called Helper T cells. After binding to CD4, HIV enters the helper T cells via
receptor mediated endocytosis. The new HIV copies bud off from the cell’s plasma membrane and
circulate into blood to infect other cells. HIV mainly damage Helper ( CD4 + ) T cells. Over 10 billion
HIV viral copies may be produced each day. After a period of 2 to 10 years, the virus destroys
enough CD4 + T cells that results immunodeficiency.
Restriction endonuclease
These are enzymes that recognize specific nucleotide sequence in DNA and cleave the DNA double
helix at or near these specific restriction site, called Target site. So due to this behaviour, this enzyme
is specially used in Genetic engineering.
Gyrase
It is a type II topoisomerase of E.coli with the ability to introduce negative super coils into DNA.
DNA polymerase I
The major function of DNA polymerase is DNA repair and is responsible for the excision of RNA
primers used in the initiation of DNA synthesis, but DNA polymerase I cannot initiate the synthesis
of DNA chains de novo. DNA pol.I catalyses the formation of a phosphodiester bridge between the
3’-OH at the end of the primer chain and the 5’- phosphate of incoming deoxyribonucleotide. The
direction of synthesis is thus always 5’ – 3’.
Insectivorous plants
Drosera
It is called Sundew because of the shining of the leaves by the secretion. Insects
Attracted by the shining will get entrapped and the leaf closes.
Nepenthes
It is called Pitcher plant because the leaf is modified into a pitcher. The pitcher has
Nectar for attracting insects.
Utricularia
It is the Bladder wort. The segmented leaves modified into bladder. It is free floating
Water plant with out roots. The aquatic insects get entrapped in the bladder will be
Digested by the enzymes.
ATP during Glycolysis
Net gain of ATP is 8. One glucose gives 2 Pyruvic acids.
1 Pyruvic acid gives 2 ATP molecules.
1 reduced NAD generates 3 ATP molecules.
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So total 5 ATP molecules are produced per Pyruvic acid.
So net gain is 5 x 2 = 10 ATP
Of these 2 ATP is used for phosphorylation.
Each ATP carries about 60 k.cal energy which is about 10 % of total energy present in the glucose.
The remaining 90 % energy is available in the pyruvic acid.
Kreb’s cycle
The net products from the 2 pyruvic acids are 6 NADH, 2 FADH2, and 2 ATP.
10 NADH2 + 2 FADH2 + 4 ATP are formed per glucose molecule.
10 NADH2 produces
30 ATP and
2 FADH2 produces
4 ATP during electron transport chain. Net gain 34 ATP.
Net gain from NADH2, FADH2 is
Net gain from Glycolysis
Net gain from glycolysis
Total ATP from each glucose
ATP used to transport NADH2
So net gain of ATP
Energy level
Glycolysis
Acetyl CoA formation
Kreb’s cycle
Total
8 ATP
6 ATP
24 ATP
38 ATP
ATP from Hydrogen acceptors
4 NADH2 X 3 ATP
1 FADH X 2 ATP
1 GTP
X 1 ATP
Total
12 ATP
2 ATP
1 ATP
15 ATP
34 ATP
2 ATP
2 ATP
38 ATP
2 ATP
36 ATP
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Cladistcs
Classification based on genologies alone in inferring phylogenic relation ships.
Phylogenetcs
Classification concerned with reconstruction of evolutionary history.
Nanotechnology
It is based on manipulation of atoms and molecules to design assemblies which can perform usual
works. For example, Nanocomputer made up of atoms and molecules. One such Nanocomputer can
be placed in the brain to enhance human intelligence. Other prospects of nanotechnology are
biosensors, optoelectronic devices etc.
Competitive inhibition
Substances similar in structure with the substrate inhibits enzyme action is the competitive inhibition.
For example, Malonate resembles Succinate. Enzyme Succinate dehydrogenase is inactivated by
Malonate.
Non- Competitive inhibition
A substance that has no structural similarity with the substrate, bind at a different site of enzyme and
cause inhibition. For example, Cyanide inhibits Cytochrome oxidase. Silver ions act on Saccharase
enzyme of yeast and cause inhibition. This is the basis of Silver pollution in the Ecosystems.
Allosteric enzymes
Some substances bind to the specific site of enzyme other than the active site and modify its action.
These are allosteric enzymes. Foe example, Phosphofructokinase catalyse phosphorylation of
Fructose – 6 – phosphate to Ftuctose 1,6 diphosphate. When ATP is present at high concentration, it
act as an allosteric inhibitor for the enzyme.
Feed back inhibition
The products of some reaction will inhibits the enzyme action. This is feed back inhibition. For
example, Bacteria coverts L-Threonine to L- Isoleucine. If L- Isoleucine is added to the culture, the
reaction stops. The enzyme L-Threonine deaminase is inhibited.
Science of exceptions
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Rhizopora and Sonneratia are Mangroove plants with negatively geotropic roots.
2.
Leaves of monocots like Smilax, Colocasia show Reticulate venation.
3.
Leaves of dicots like Calophyllum, Corymbium show Parallel venation.
4.
Cuscuta lacks Cotyledons.
5.
Blood of shark is colour less.
6.
Duck billed platypus and Spiny Anteater are Egg laying mammals.
7.
Protopterus and Lepidosiren possess Lungs.
8.
Ostrich, Kiwi, are ratitae birds .
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9.
Honey bee male is formed through Parthenogenesis and are haploids.