Mendel's Hybridisation experiment

• Mendel selected 22 varieties of pea plant for his experiments.

• Mendel studied  total 7 characters of inheritance in which each character is having two contrasting forms but consider only one contrasting character at a time.

• He took a pure tall pea plant and pure dwarf pea plant and cross pollinated them. that is the pollen grains of tall plant are dusted over the stigma of Dwarf plant and vice versa.

• Plants produce from these generation were all tall.
  

• All plants of first generation were called first filial generation or F1 generation by Mendel.

• Now when tall plants of F1 generation are self pollinated and the seeds obtained  were sown then all plants were not tall but there were dwarf plants also.

• The phenotypic ratio of these tall plants and  dwarf plants was 3:1 that  is 75% plants were tall and 25% plants were dwarf.

• Offsprings obtained from F1 Generation were called second filial generation or F2  generation by Mendel.

• The genotype of 3 tall plants and 1 dwarf plant in F2 generation is

1 Pure Tall (TT)

2 Hybrid tall (Tt)

1 Pure dwarf (tt)

• And the genotypic ratio was 1:2:1

• Mendel drew some conclusions from his experiments:-

1. Whatever may be the parents, reciprocal crosses always gives same results. For example, In original or basic cross between tall male and dwarf female all F1 generation plants were tall and in reciprocal cross between dwarf male and tall female the F1 generation plants  were also tall.
2. Out of two contrasting characters, only one is expressed in F1 Generation and other remain hidden and on self pollinating plants of F1 generation, the hidden characters will reappeared in F2 generation.
3. This experiment all revealed that the dwarf character only remain hidden in F1 generation but not completely disappeared because they reappeared in F2 generation.

• Traits which appeared in F1 generation are called Dominant characters and the characters which is hidden in F1 generation and reappeared in F2 generation is called recessive character.

Experiments to prove Carbondioxide is necessary for photosynthesis

Take a potted plant having a long and narrow leaves

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Destarch it by placing a dark room

 (leaf can be destarch by keeping this plant in dark room for at least 3 days. The plant will use up all the starch stored in its leaves in about three days as in dark room the plant cannot make more starch because there is no sunlight)

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Take a wide mouth glass Bottle and put potassium hydroxide in it

(Potassium hydroxide solution absorb Carbondioxide gas present in air)

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In glass Bottle no Carbondioxide is left

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Take the rubber cork and cut it into two halves

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Put the destarch leaf inside the bottle in between the two halves 

(Leaf is still attached to the plant)

As half part of leaf is inside the bottle and remaining half remains outside the bottle

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Now keep this potted plant in sunlight for 3-4 days 

(During this period the upper half of leaf gets Carbondioxide from the air and lower half leaf cannot get Carbondioxide

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Now pluck the leaf and remove chlorophyll as chlorophyll is a green colour pigment it interferes in the starch test.

(Chlorophyll can be removed from the leaf by boiling it in alcohol. Alcohol is flammable this we add water and then boil it)

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Boil the leaf untill it becomes pale yellow and the alcohol becomes green

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Leaf is washed with water to remove extra chlorophyll stuck to it

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Now after removing chlorophyll, the leaf is tested for the presence of starch

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To check the presence of starch we drop the iodine solutions on leaf 

(Starch gives blue black colour with iodine)

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The one part of decolourised leaf becomes blue black in colour means starch is present here.

(the part of leaf which is outside or in contact with Carbondioxide become blue black in colour)

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The other part of leaf remain colourless on adding iodine drop

(The part of leaf which is inside the bottle or not in contact with Carbondioxide remain colourless)

As the start gives blue black colour with iodine here it doesn't give that type of colour, it shows that starch is not present here

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As starch is only formed in presence of Carbondioxide, thus the experiment shows that Carbondioxide is necessary for photosynthesis.

Nutrition in plant, photosynthesis, events in photosynthesis, conditions necessary for photosynthesis

• Nutrition in plants :-

Green plants are autotrophic thus prepare their own food by the process of photosynthesis .

• Photosynthesis:-

It is a process by which green plant synthesise organic food . This food is prepared by green plants from Carbon dioxide  and water in the presence of Sunlight and chlorophyll.  

Reaction involved:-

6Co₂+12H₂o→C₆H₁₂O₆+6H₂O+6CO₂↑

The plants use the energy in Sunlight to prepare food from Carbon-di-oxide , and water in presence of Chlorophyll.

The leaves of a plant are green because they contains tiny green coloured organelles called Chloroplast.

Chlorophyll  ( green coloured pigment) is present in the green coloured  bodies called “chloroplast” inside the cells.

Thus , Chloroplast are the site of photosynthesis as they contain Chlorophyll pigment.

• Events in photosynthesis:

Firstly the Absorption of light energy is done by chlorophyll.
Then Light Energy is converted into chemical Energy .
And the Reduction of carbondioxide to Carbohydrates (starch) .

All the above steps may or may not  takes place one after the other immediately.

• Conditions necessary for photosynthesis:-

(1) sunlight

(2) Chlorophyll

(3) Carbondioxide

(4) Water

Mode of nutrition (autotrophic nutrition, Heterotrophic nutrition), Types of Heterotrophic nutrition- Holozoic nutrition, saprophytic nutrition, parasitic nutrition) for class 10 in simple language for understanding And notes cbsc and mpboard

by-https://unsplash.com/@brookelark

Nutrition  

Definition:- 

Nutrition is a process by which an organism obtains nutrients from food and utilises them to obtain energy.

Nutrients:- 

Nutrientsare the substance which provide Energy to an organism for their growth and maintenance .

Examples of Nutrients-Carbohydrates, fats, protein and minerals and vitamins.

Modes of Nutrients:-

It is a method of obtaining food from Surrounding by an organism. There are two modes of Nutrition:-

Autotrophic Nutrition and Heterotrophic Nutrition

(1) Autotrophic Nutrition:-

The type of  nutrition in which organism  Synthesis their own food from inorganic materials like carbon-di-oxide and water  is called Autotrophic Nutrition.
*Chlorophyll is required.

The organism having Autotrophic mode of nutrition see called Autotrophes.

For example: Green plants and some bacteria.

(2) Heterotrophic Nutrition:-

 The type of nutrition in which organism cannot prepare their own food. They depend on autotrophs (directly or indirectly)  for their food.

The organism having heterotrophic mode of  Nutrition are called heterotrophs.

For Example- Animals, fungi.

Heterotrophic nutrition may be  of following types:-

(A) Holozoic nutrition -

In this type of nutrition complex food is taken in  and then broken down into simpler form inside the body.

For example- Herbivores (plant eaters), Carnivores (meat eaters) and omnivorous (both plant and meat eaters), amoeba, cow, dog, cat goat, humans etc.

(B) Saprophytic Nutrition:- 

Organism which feed Organism upon dead decaying matter called Saprotrophs and mode of nutrition is called Saprophytic nutrition.

For example-  fungi, mushrooms, yeast and bacteria etc.

(C) Parasitic nutrition:- 

Parasites having parasitic nutrition are live inside or outside the other organism (host) and obtain their nutrition without killing them.

For example- Plasmodium, ticks , live, leech, tapeworm, plants like -  Cuscuta (amarbel) etc.

Respiration process (aerobic respiration, anaerobic Respiration, alcoholic fermentation, lactic acid fermentation ) simple language for class 10 CBSE , MP board

The food we take during nutrition used to obtain energy by the process of respiration.

Some organism use oxygen during respiration ( aerobic respiration) while some not use oxygen during respiration (anaerobic respiration)

Following points to be known to understand the respiration process in easy way:-

• Glucose - (C₆H₁₂O₆) It is 6 carbon containing molecule.
• Pyruvate - It is 3 carbon containing compound which form after the breakdown of glucose .It is also known as pyruvic acid. One molecule of glucose gives 2 molecule of pyruvate. Oxygen is not used in the process of breaking glucose to pyruvate and occurs in cytoplasm of cell. 

• Lactic acid - It is also a 3 carbon containing molecule. Also known as lactate.

• Pyruvate is further oxidized in presence of oxygen in (aerobic respiration) or absence of oxygen in (anaerobic respiration)

 

• If oxygen is not presence inside the cell (aerobic respiration) pyruvate is either converted to ethanol and carbon-di-oxide or lactic acid.

Types of respiration-

Aerobic Respiration - 

It is the process of  breakdown of glucose in the Presence of oxygen into carbon-di-oxide and  large amount of Energy is Released.

In this firstly the glucose molecule breaks into pyruvate molecule inside the cytoplasm & then in presence of oxygen the pyruvate molecule breaks into Carbon-di-oxide and water inside mitochondria .

Reaction involved:-

Glucose→Pyruvate+Energy→6carbon-di-oxide+6water+energy

Or

C₆H₁₂O₆→Pyruvate+E+6O₂→6CO₂+6H₂O +38ATP

Important point- Mitochondria is the site of aerobic respiration.

Anaerobic Respiration-

 It is the process of breakdown of glucose in the absence of oxygen in which Small amount of energy is released. It takes place in yeast, bacteria ad human beings. Anaerobic Respiration only occurs in the cytoplasm. 

Anaerobic respiration is of two types on the basis of product formed :-

 Alcoholic Fermentation :-

 In this process incomplete breakdown of  

Glucose occurs in absence of oxygen into ethanol and carbon-di-oxide. This process

is called alcoholic fermentation which mainly occurs in yeast, used to prepare beer, Cheese, toddy, wine etc. 

Reaction involved:-

Glucose→pyruvate+Energy→2Ethanol+2carbon-di-oxide+energy

Or

C₆H₁₂O₆→Pyruvate+E→2C₂H₅OH+2CO₂+2ATP

Lactic acid fermentation -

 In this process  incomplete breakdown of glucose occurs in absence of Oxygen into lactic acid. This process is called Lactic acid fermentation and Occurs in Some bacteria (Lactobacillus) present in Yogurt.

 This process also occurs in human muscles when person do physical exercise vigorously, glucose is metabolised to form lactic acid  and it accumulates in muscle Causes fatigue and cramps.

Reaction involved:-

Glucose→Pyruvate+Energy→2Lactic acid+energy

Or

C₆H₁₂O₆→Pyruvate+E→2Lactic acid+2ATP

  

Polymerase chain reaction notes- definition, principal, requirements, mechanism

Introduction of PCR-   The polymerase chain reaction was developed by an American biochemist Kary Mullis in the year 1983. By Using PCR it is possible to generate thousands to millions of copies of a particular section of DNA from a very small amount of DNA

• Definition-

 Polymerase chain reaction (PCR) is a lab  techniques of gene amplification with the help of which identical Copies of desired DNA can be Synthesized within a time of short duration.

• Principle of PCR-   

Principle of PCR is based on the ability of DNA polymerase to synthesize new strand of  DNA Complementary to the offered template strand Because DNA polymerase can add a nucleotides only onto the  preexisting -OH group, at the end of the reaction billions of copies are formed.

• Requirements :- 

1. DNA template: Any Source that contains one or more target DNA molecule to be amplified can be taken as DNA template.
2. Taq polymerase -PCR requires a DNA Polymerase enzyme that makes new Strands of DNA using strands as templates. The DNA polymerase used in PCR is Taq polymerase which is isolated from a thermostable bacterium called Thermus aquaticus. It lives in hot Spring and very stable and is  most  active around  70 degree Celsius.Primers- Taq Polymerase can only make DNA when  it is given a primer.
3.  Primer is a very short sequence of nucleotides which provide a starting point for the synthesis of DNA.
4. Two 15-35 nucleotide long oligonucleotide primers which are complimentary to both the strands of target DNA.
5. All four types of deoxyribonucleotides are required- dATP, dGTP, dCTP, dTTP .

All the above mentioned items are mix together to make a reaction mixture.

• Working mechanism of PCR

The process of PCR involves heating and cooling called thermal cycling which is carried out by machine 

called Thermocycler. 

There are three steps in one amplification cycle:- 

1. Denaturation 

2. Annealing or renaturation 

3. Extension 

1)Denaturation-

Firstly, the reaction mixture is heated at about 95C for one minute as a result of which the hydrogen bond between two DNA strands are breaks and two single strands of DNA are completely separated.

 

After denaturation the reaction mixture is slowly cooled down to 55- 66C temperature which is favorable for primers to bind the single stranded DNA strand by way of hydrogen bonding. This process is also called renaturation. 

3) Synthesis or extension or polymerisation:-

It is the final step of amplification cycle. IN the presence of Mg++ ions and dNTPs. (example - dATP, dGTP, dCTP, dTTP). 

Taq polymerase which is a thermostable bacteria initiates the synthesis of DNA at 3’ hydroxyl end of each primer and The primers are extended by joining the bases complementary to DNA strands. Thus, in the first cycle the target DNA is copied from the primer sites for various distances until the second cycle starts. 

After that second cycle of amplification is started for this the DNA strands are denatured which are original and newly synthesized long templates annealed with primers and subjected to DNA 

synthesis. 

 The no. of DNA strands becomes four times at the end of second cycle. In this way at the end of 32nd cycle of PCR, about million fold target DNA is synthesized. 

 After PCR has been completed the results are usually visualize using gel electrophoresis (A technique in which fragments of DNA are pulled through gel by a electric current and it separates DNA fragment according to size.

Properties of Immunoglobulin G - Notes for College students and all the points to be added in exams to get good marks

• Molecular weight of immunoglobulin G is 150,000.
• Serum Concentration of immunoglobulin G is→ 12 mg/ml .H-chain type of immunoglobulin G is gamma.
• Percent of immunoglobulin G in total immunoglobulins is - 80%
• longest half life of immunoglobulin G is 23 days.
• Immunoglobulin G Produce secondary response.
• Immunoglobulin G can activate Complement System.
• Immunoglobulin G is provide immunity to foetus.
• Immunoglobulin G is Bivalent antibody.
• Immunoglobulin G is only antibody to pass from placenta.