Krebs' Cycle

Pyruvic acid which is produced in glycolysis is transported into the mitochondria where it is converted into acetyl CoA. Then, CoA enters the Krebs' cycle that takes place in the matrix of the mitochondria. 

NADH2 and FADH2 are generated in the Krebs' cycle. 

Glycolysis

In cellular respiration, oxidation of glucose takes place. The initial stage of cellular respiration takes place in the cytoplasm. Glucose molecule is broken down through a series of enzyme-catalyzed reactions into two molecules of pyruvic acid. This process is known as glycolysis.

Note: The above notes in the image(s) are taken from a personal notebook which was initially not intended to be shared online. Please excuse the rough handwriting and the spelling errors, if any. 

Morpankhi plant

This is an oriental thuja (मोरपंखी) plant (Platycladus orientalis also called Thuja orientalis). 

It is a gymnosperm and belongs to cypress family. It is used as ornamental plant or as hedges in gardens. 

Canna flower

This is a flower of canna plant, also called canna lily (Canna sp) . 

The flowers may be yellow, orange, red etc or in a combination of these colours.

It is a monocot plant and looks slightly like a banana plant. 

It has contractile roots. 

Its rhizome is rich in starch. 

CAM Cycle and Photorespiration

Crassulacean Acid Metabolic Cycle or CAM cycle is found in in plants of crassulaceae family eg Kalanchoe pinnate (bryophyllum) and euphorbiaceae family eg Euphorbia sp, codiaeum variegatum etc. 

Photorespiration:

Photo respiration occurs in C3 plants. In C3 cycle, rubisco enzyme binds with carbon dioxide and and through the cycle it produces glucose. Some of the rubisco enzyme also binds with oxygen, if the amount of oxygen is high and temperature is high. Thus, the amount of glucose produced is less. Moreover, some of the glucose produced is also oxidized which causes further loss of glucose. This is called photo respiration because it is not the main respiration which takes place in mitochondria but another type of respiration which takes place in the presence of sunlight. 

C4 Cycle

Some tropical plants like maize, sugarcane, many grasses, sorgam, millet, many plants of asteraceae, many plants of brassicaceae etc show a special type of photosynthesis called C4 cycle or C4 pathway. In this type of pathway, the first product of carbon dioxide fixation (malic acid or aspartic acid) is formed in the cells of mesophyll. It is a 4 carbon compound. 

Malic acid is transferred to the bundle sheath cells where it is converted into pyruvic acid. Pyruvic acid then takes part in the C3 cycle or Calvin cycle.

Class 11 Photosynthesis

In the mesophyll cells of the leaves, there are a large number of chloroplasts. The membranes of granna inside chloroplast are the site for the light reaction while the dark reaction takes place in the matrix of the chloroplast ie stroma. 

In the light reaction, the light energy is absorbed by the pigment present in the antenna and funneled to special chlorophyll a molecules called Reaction Centre chlorophylls. 

There are two photo systems, PS1 and PS2. PS1 has a 700 NM absorbing chlorophyll called Chlorophyll a P700 molecule at its reaction centre, while PS2 has a P680 reaction centre that absorbs red light at 680 NM. After absorbing light, electrons are excited and transferred through PS2 and PS1 and finally to NAD forming NADH. 

Initially, in the dark reaction, carbon dioxide is added by the enzyme RuBisCO to a 5 carbon compound RuBP that is converted to two molecules of 3 carbon PGA. This is then converted to glucose. In this process, ATP and NADPH synthesized in the light reaction are utilised. 

Note: The above notes in the image(s) are taken from a personal notebook which was initially not intended to be shared online. Please excuse the rough handwriting and spelling errors, if any. 

Plant Life Cycle and Metagenesis

In the life cycle of sexually reproducing plants, there is alternation of generations (metagenesis) between gamete-producing haploid gametophyte and spore-producing diploid sporophyte.

However, different plant groups as well as individual plants may show different patterns of life cycles. 20 life cycles are haplontic, diplontic or haplo-diontic (intermediate).

Note: The above notes in the image(s) are taken from a personal notebook which was initially not intended to be shared online. Please excuse the rough handwriting and the spelling errors, if any. 

Class 11 Gymnosperm

The gymnosperms have ovules which are not enclosed by any ovary wall. The seeds remain exposed after fertilization and so these plants are called naked-seeded plants. The gymnosperms produce microspores and megaspores in microsporangia and megasporangia respectively. Microsporangia are borne on microsporophylls while megasporangia are borne on megasporophyll. These sporophylls are arranged spirally on axis to form male and female cones. The pollen grain germinates and pollen tube releases the male gamete into the ovule, where it fuses with the egg cell in archigonia. After fertilization, the zygote develops into embryo and the ovules into seeds. 

Note: The above notes in the image(s) are taken from a personal notebook which was initially not intended to be shared online. Please excuse the rough handwriting and spelling errors, if any. 

An Important Observation on Periwinkle Flowers

Dear readers,

This article discusses an important observation in my garden.

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This is a Periwinkle plant ( Catharanthus roseus, formerly known as Vinca rosea) with dark pink flowers with white centre.

Only one sapling was brought to the garden a few months ago. There was no other periwinkle near by. Later, the plants spread in the garden and gave flowers of different colours. 

Like, 

1. Light pink flower with dark pink centre

2. Light pink flower with white centre

3. White flower with white centre

4. White flower with light pink centre

In this way, we got periwinkle plants with five kinds of flowers.