movement of water in plants

circulation of blood in humans

HUMAN RESPIRATORY SYSTEM

Human Respiratory System - American Lung Association site

Tutoring, Biology, Biology Tutoring, Animal Nutrition, Carbohydrates, Proteins, Vitamins, Holozoic Nutrition, Digestive Glands and Their Secretions - Tutorvista.com

Tutoring, Biology, Biology Tutoring, Animal Nutrition, Carbohydrates, Proteins, Vitamins, Holozoic Nutrition, Digestive Glands and Their Secretions - Tutorvista.com

REPRODUCTION AND DEVELOPMENT OF FLOWERING PLANTS (ANGIOSPERMS)

Flowering plants have sporophyte and gametophyte stages. The sporophyte is diploid and consists of roots, stems, and leaves. The sporophyte produces flowers for sexual reproduction. Flowers produce haploid spores that develop into gametophytes. The female gametophyte is embeddcd in floral tissues. The male is released as pollen grains.

Accessory structures form the non reproductive parts of the flower.

A flower has a ring of leaf like sections round the base.
These are called SEPALS.
Inside the SEPALS are the PETALS.
The PETALS can be a variety of shapes and colours.
The PETALS form the COROLLA.
The SEPALS form the CALYX

Reproductive parts include the stamens (male) and carpels (female).

1) THE STAMEN
Inside the COROLLA are slender stalks.
These are called FILAMENTS.
At the end of the FILAMENT is the ANTHER.
The ANTHER and the FILAMENT together form the STAMEN.
The STAMEN is the MALE reproductive ORGAN.
Pollen grains are found on the ANTHER.
2) CARPEL
At the centre of the COROLLA is the CARPEL.
This is the FEMALE reproductive ORGAN. It is made up of the:
1)STIGMA

2)STYLE

3)OVARY.
The pollen from the male part, the STAMEN, is needed to fertilise the female part, the CARPEL.
The female reproductive organ is the CARPEL
The male reproductive organ is the STAMEN

Pollen is basically sperm packed inside a nutritious package. When it first evolved it was transferred by wind currents. Later it was transferred by insects. Most species of angiosperms have coevolved with pollinators attracted to their pollen and nectar. Coevolution refers to two (or more) species jointly evolving as an outcome of close ecological interactions. Plants with flowers that attracted insect pollinators had a reproductive advantage. Plant structures that were more attractive to pollen-delivering insects were favored. The more attractive plants proved to be good sources of food for the insects.
In the ovary, eggs develop, fertilization occurs, and seeds mature.

SO LET'S HAVE A LOOK AT WHAT MAKES UP THE OVARY
The OVARY contains one or more OVULES.
The OVULES are the parts that develop into seeds. They contain female egg cells.

Double fertilization is a distinctive feature of angiosperms. The male gametocyte delivers two sperm to an ovule. One sperm fertilizes the egg and the other fertilizes a cell that gives rise to endosperm that supports the embryo.Pollination is the transfer of pollen grains to the surface of a receptive stigma. Wind, insects, birds, or other agents are often required for the transfer. After a pollen grain lands on a stigma, it germinates and a pollen tube forms, creating a path that the two sperm nuclei will follow to the ovule.
Guided by chemical cues, the pollen tube grows through the tissues of the ovary to an ovule. It carries two sperm nuclei. When the pollen tube reaches an ovule, it penetrates the embryo sac and deposits two sperm. The two sperm are released to accomplish double fertilization.
One sperm fuses with (fertilizes) the egg nucleus to form a diploid zygote. The other sperm nucleus fuses with the two endosperm nuclei to yield a triploid "primary endosperm cell," (endosperm mother cell) that will nourish the young sporophyte seedling.
Endosperm formation occurs only in angiosperms. The fusion of a sperm nucleus with the two nuclei of the endosperm mother cell produces a triploid (3n) cell. This cell will give rise to the endosperm, the nutritive tissue of the seed.

CELLULAR RESPIRATION

PHOTOGALLERY OF CELLULAR RESPIRATION

CELLULAR RESPIRATION

Cellular respiration is the process by which the chemical energy of "food" molecules is released and partially captured in the form of ATP. Carbohydrates, fats, and proteins can all be used as fuels in cellular respiration, but glucose is most commonly used as an example to examine the reactions and pathways involved.

GLYCOLYSIS

This process occurs in the cytoplasm irrsepective of the presence or absence of oxygen.In glycolysis, the 6-carbon sugar, glucose, is broken down into two molecules of a 3-carbon molecule called pyruvate. This change is accompanied by a net gain of 2 ATP molecules and 2 NADH molecules.

KREB CYCLE

The Krebs cycle occurs in the mitochondrial matrix and generates a pool of chemical energy (ATP, NADH, and FADH2) from the oxidation of pyruvate, the end product of glycolysis.Pyruvate is transported into the mitochondria and loses carbon dioxide to form acetyl-CoA, a 2-carbon molecule. When acetyl-CoA is oxidized to carbon dioxide in the Krebs cycle, chemical energy is released and captured in the form of NADH, FADH2, and ATP.


OXIDATIVE PHOSPHORYLATION VIA THE ELECTRON TRANSPORT CHAIN

The electron transport chain allows the release of the large amount of chemical energy stored in reduced NAD+ (NADH) and reduced FAD (FADH2). The energy released is captured in the form of ATP (3 ATP per NADH and 2 ATP per FADH2).
NADH + H+ + 3 ADP + 3 Pi + 1/2 O2 ---> NAD+ + H2O + 3 ATP
FADH2 + 2 ADP + 2 Pi + 1/2 O2 ---> FAD+ + H2O + 2 ATP
The electron transport chain (ETC) consists of a series of molecules, mostly proteins, embedded in the inner mitochondrial membrane.


HOW RESPIRATION MAKES ENERGY

Respiration is the release of energy from glucose or other organic substances. Energy is required for growth, repair, movement and other metabolic activities.


There are two main types of respiration -

1) Aerobic respiration

2) Anaerobic respiration


AEROBIC RESPIRATION

It takes place in the presence of oxygen.Glucose molecules react with oxygen molecules to form carbon dioxide and water molecules, with energy being released by the breaking of bonds in the glucose molecules.The energy released from glucose in respiration is used to produce a chemical called adenosine triphosphate (ATP). ATP is where the energy released during respiration is stored for future use.
Glucose + Oxygen ---> Carbon Dioxide + Water + Energy
A lot of energy is released in aerobic respiration - 2900 kj from one glucose and 6 oxygen molecules.


ANAEROBIC RESPIRATION

It occurs when oxygen is not available. In anaerobic respiration the glucose is only partially broken down, and lactic acid is produced - together with a much smaller amount of energy.

Glucose ---> lactic acid + carbon dioxide + energy
This extra oxygen needed to neutralise the harmful effects of anaerobic respiration is called an oxygen debt. In order to get the extra oxygen to 'pay back' the debt, the body continues to breathe deeply for some time after vigorous activity has ceased. When all the lactic acid in the muscles is broken down the oxygen debt has been repaid and normal aerobic respiration resumes.


One measure of a person's fitness is how quickly their breathing and pulse return to normal after exercise. This is because in a fit person aerobic respiration is more efficient, so they build up less of an oxygen debt while exercising, and need less extra oxygen to breakdown any lactic acid in their muscles resulting from anaerobic respiration.
When anaerobic respiration occurs in yeast it is called fermentation. In this case ethanol (alcohol) is produced instead of lactic acid, and this reaction is used in the brewing of alcoholic drinks.
Glucose ---> ethanol + carbon dioxide + energy
All cells are able to synthesize ATP via the process of glycolysis. In many cells, if oxygen is not present, pyruvate is metabolized in a process called fermentation.Fermentation complements glycolysis and makes it possible for ATP to be continually produced in the absence of oxygen. By oxidizing the NADH produced in glycolysis, fermentation regenerates NAD+, which can take part in glycolysis once again to produce more ATP.


During vigorous exercise the body needs a lot more energy. It gets this by breathing in deeper and faster and rushing the oxygen to the muscles in dilated blood vessels. This extra oxygen is then used to release more energy, needed to meet the higher level of demand. Soon a point is reached when the body cannot breathe any faster or harder, and aerobic respiration alone cannot meet the enhanced energy demands. So how do muscle cells get the extra energy they need? They get it by respiring anaerobically.


But anaerobic respiration produces lactic acid, which accumulates in the muscles and causes muscle fatigue and cramps. To avoid damage to cells, lactic acid has to be broken down to carbon dioxide and water immediately the exercise has finished. This is an oxidisation reaction, and requires oxygen.

This extra oxygen needed to neutralise the harmful effects of anaerobic respiration is called an oxygen debt. In order to get the extra oxygen to 'pay back' the debt, the body continues to breathe deeply for some time after vigorous activity has ceased. When all the lactic acid in the muscles is broken down the oxygen debt has been repaid and normal aerobic respiration resumes.

One measure of a person's fitness is how quickly their breathing and pulse return to normal after exercise. This is because in a fit person aerobic respiration is more efficient, so they build up less of an oxygen debt while exercising, and need less extra oxygen to breakdown any lactic acid in their muscles resulting from anaerobic respiration.

PLANT TISSUES

CLIPS TO UNDERSTAND MEIOSIS

NOTE - VIDEO TO EXPLAIN MEIOSIS HAS ALSO BEEN ADDED TO THIS BLOG.VIDEO IS JUST NEXT POST TO THESE CLIPS !

VIDEO OF MEIOSIS

KHADIN - THE TRADITIONAL WATER HARVESTING SYSTEM

A khadin, also called a dhora, is an ingenious construction designed to harvest surface runoff water for agriculture. Its main feature is a very long (100-300 m) earthen embankment built across the lower hill slopes lying below gravelly uplands. Sluices and spillways allow excess water to drain off.

PRINCIPLE -The khadin system is based on the principle of harvesting rainwater on farmland and subsequent use of this water-saturated
land for crop production

First designed by the Paliwal Brahmins of Jaisalmer, western Rajasthan in the 15th century, this system has great similarity with the irrigation methods of the people of Ur (present Iraq) around 4500 BC and later of
the Nabateans in the Middle East. A similar system is also reported to have been practised 4,000 years ago in the Negev desert, and in southwestern Colorado 500 years ago.

Sensing and Geographical Information Systems can help in the determination of areas suitable for water harvesting (Prinz et al. 1998).Khadin- A traditional successful water harvesting system in India Khadin is an ancient skilful and sound scientific example of rainwater harvesting system in Western Rajasthan/ India.

STRUCTURE - A Khadin is an earthen embankment built across the general slope which conserves the maximum possible rainwater runoff within the agricultural field. The size of the Khadin is designed on the basis of local rainfall patterns, catchment characteristics and soil type. On an average, the cultivated area under each Khadin is 10-14 ha with an average dam size between 1.2-1.7 m high x 1.0-1.5 m wide and 100-300 meters in length, depending upon catchment area and number of land holdings. The spillways and sluice gates are usually provided at a proper location for excess water during flood conditions. The embankment not only helps to increase moisture in the submerged land, but also prevents the washing away of the top soil and the manure added to it.
For efficient agriculture, a minimum of 15:1 ratio of catchment area to crop area is required. A rainfall of 75-100 mm is sufficient to charge the Khadin soils with sufficient soil moisture content to raise a successful local crop. In the Khadin area, the collect runoff percolates into the ground with time recharges the subsoil.Of the total runoff collected only 50-60% of the water is utilised. The remainder is lost to evaporation, or percolates into the underground, recharging an aquifer.
Depending upon the amount of rainfall and consequent runoff received during the monsoon, one or two crops are grown. There is 3-4 fold increase in agriculture production, in comparison with non-Khadin conditions depending upon rainfall quantity and distribution. This system assures the farmers of at least one crop even in very dry tracts. The construction cost for single Khadin ranges from US $ 125-175. This construction cost can be repaid back within three to five years. Other than improving socio-economic conditions of desert dwellers, Khadins also have created positive impact on the ecology of the region, effectively checking soil erosion and increasing vegetation cover.

PHOTO GALLERY OF PHOTOSYNTHESIS

PHOTOSYNTHESIS 1

The power for life,that we call energy, flows into the food chain through our friends the busy plants. The plants do something with that energy that seems miraculous. They turn it into food. This is very nice of the plants because animals can't eat sunshine. They can only eat plants or each other.

The Leaf -
It's amazing what's inside a leaf.The whole leaf looks green to us,but most of the cells and cell material are colourless or clear. The green color comes from the chlorphyll molecules in the chloroplasts.

Leaf Section-
Cut out a little section of the leaf.There are many different types of cells, specialized to do different things - all for the good of the tree, of course.On the top and bottom are the cuticle layer and the epidermal cells.In the middle, between the epidermis cells on the top and bottom, are the mesophyll cells where the chloroplasts live. On the bottom only, in most plants, are the stomatas which let carbon dioxide in and oxygen out.

Mesophyll Cells -
The chloroplasts, where photosynthesis occurs, are in the mesophyll cells.There are two kinds of mesophyll cells in our typical leaf. a)The palisade parenchyma region-this is where most photosynthesis is done.
b)The spongy parenchyma region. Here the cells aren't so close. There are roomy air spaces between them.

Chloroplast -
Each chloroplast is a little carbohydrate factory, powered by solar energy, & for which the only raw materials are carbon dioxide, water, and a few minerals.Out of this little factory comes food for plants and practically every other living thing on earth - including us.

Granum-
The little round flat pillow or pancake shaped things are called thylakoids. A stack of them is called a granum. Two or more stacks are called grana.There can be from 2 to around 100 thylakoids in one granum. The little tube like strands connecting thylakoids from granum to granum are called stroma lamellae.

Thylakoid
The chlorphylls and other pigments that start the process are here, on the outer layer of the thylakoids. Photons from sunlight hit the pigments, electrons are "knocked" loose, and off they go to energize the complicated process of photosynthesis.Sometimes the thylakoid is also called the photosynthetic membrane.The membrane and the space inside it,is where the light or light-dependent reaction takes place. The so-called dark, or light independent reactions, take place in the stroma.This power for life,that we call energy, flows into the food chain through our friends the busy plants.

Mechanism of photosynthesis
Photosynthesis occur in two phases.Photochemical(light reaction) & Biochemical(dark reaction).
1)Light reaction- also called Hill reaction because it was discovered by R Hill.In light reaction photolysis of water take place in grana.
a)Photolysis of water -water molecule is split into hydrogen & oxygen.It also indicates that oxygen which is released is derived from water & not from carbon dioxide.
b)Formation of ATP -
i)Photophosphorylation takes place which means formation of ATP from ADP & inorganic phosphate.
ii)NADP get reduced.

2)Dark reaction- The dark reaction takes place in the stroma within the chloroplast, and converts CO2 to sugar. This reaction doesn't directly need light in order to occur, but it does need the products of the light reaction (ATP and another chemical called NADPH). The dark reaction involves a cycle called the Calvin cycle in which CO2 and energy from ATP are used to form sugar. Actually, notice that the first product of photosynthesis is a three-carbon compound called glyceraldehyde 3-phosphate. Almost immediately, two of these join to form a glucose molecule.
The overall chemical reaction involved in photosynthesis is:
6CO2 + 6H2O (+ light energy) C6H12O6 + 6O2.

PHOTOSYNTHESIS

Photosynthesis is important to you. It keeps you, everybody, and everything else alive. You'll never look at plants or slime the same. You won't want to interrupt the grass by stepping on it. Don't bother the diatoms. They're busy. Photosynthesis in progress!Energy pours onto the earth in the form of electromagnetic radiation that most of us call sunshine. The sun's energy heats the earth, makes weather, keeps us warm - thanks a lot. But if that was all, this would still be a pretty dead planet, and there would be no me and no you. Plants and animals need energy to live, to grow, and to make more of themselves. All that solar energy pouring onto the earth everyday wouldn't do us any good if we didn't have some way to turn it into a form of energy that we can use. Autitrophic life forms have "stepped-up" to save the day. They've developed a way to take sunshine, and a few common molecules from air and water, and turn them into something that the rest of us "non-autotrophs" can use. Everyday, without fanfare or thanks, or anyone hardly noticing, these humble life forms make thousands of tons of glucose (and other carbohydrates) and put thousands of tons of oxygen into the atmosphere. Without all that oxygen and carbohydrates we animals would be in big trouble.Photosynthesis is the beginning of the amazing journey of energy and the basic materials of life from plant to animal to animal to decomposer. For the molecules and atoms that living things are made of, the journey is a cycle that repeats itself over and over. You might be made of a few carbon or oxygen atoms that were once part of a dinosaur or a wooly mammoth. For energy, the trip is sort of a one time thing - in and out. All the energy that moves through life eventually ends up as heat and radiates back into space - from whence it came. If it wasn't for that nice big dose of new energy coming in from the sun every day, we would all soon be very cold and in a permanent frozen state of "not-living".

Science World

HELLO ,

I AM SANGITA SHARMA TEACHING BIOLOGY UPTO SECONDARY LEVEL IN DL DAV SHALIMAR BAGH.THERE ARE CERTAIN ABSTRACT TOPICS WHICH ARE DIFFICULT FOR THE STUDENTS TO UNDERSTAND.BY PUTTING CERTAIN CLIPS , PICTURES , VIDEOS & RELATED DATA ABOUT SUCH TOPICS , I AM TRYING TO MAKE UNDERSTANDING OF THE SUBJECT INTERSTING & EASIER.