• The first step of the Calvin pathway is the first CO₂ fixation step.
• Respiration is the reaction where RuBP combines with CO₂ to form 2 molecules of 3PGA, that is catalysed by RuBisCO.

RuBP + CO₂ -> 2 X 3PGA

• RuBisCO has a much greater affinity for CO₂ than for O₂.
• In C₃ plants, some O₂ do bind to RuBisCO, and hence CO₂ fixation is decreased.
• The RuBP instead of being converted to 2 molecules of PGA binds with O₂ to form one molecule and phosphoglycolate in a pathway called photorespiration.
• In the photorespiratory pathway, there is neither synthesis of sugars, nor of ATP.

Biological catalysts: 

The molecules.that can speed up the chemical reactions in cells is called a biological catalyst.

Example: 
Enzyms as biological catalyst :

Enzyms are soluble protein molecules. They can speed up the chemical reactions in cells respiration,photosynthesis and making new protiens are include in this reaction. due to this reaction enzymes are some times called as biological catalyst.
In enzime catalized reaction, the substract is changed to the product via a high energy transition in the state. this state has a very short life cycle and it is stabilized by the enzyme
An example of this type of reaction is decomposition of hydrogen peroxide into water and oxygen. Although the reaction is strongly favored thermodynamically, it is very slow unless catalyzed

Nitrogen fixation occurs in the root nodules that contain bacteria ( Bradyrhizobium for soybean, Rhizobium for most other legumes). Almost all legumes can fix nitrogen. The legume family (Leguminosae or Fabaceae) includes many important crop species such as pea, alfalfa, clover, common bean, peanut, and lentil. rankia is a genus of soil actinomycetes in the family Frankiaceae that fix nitrogen, both under symbiotic and free-living aerobic conditions, while most rhizobia do not (Benson and Silvester, 1993). 

Diffusion is movement of molecules from an area of their higher concentration to area of their lower concentration.

Facilitated diffusion is movement of molecules from an area of their higher concentration to area of their lower concentration through a cell membrane with help of membrane bound protein channels or carrier proteins.

Active transport is movement of molecules from an area of their lower concentration to area of their higher concentration using energy in form of ATP by pump proteins.

The 5 kingdom classification is largely the most accepted system of modern classification mainly because of the phylogenetic placing of different groups of living organisms.

This system of classification looks more scientific and natural.

There is far less overlap and confusion in this system, as compared to the original two kingdom classification.

Grouping of all unicellular eukaryotes under the kingdom Protista has solved many problems, particularly related to the position of organisms like Euglena.

Separation of prokaryotes into an independent kingdom is justifiable because they differ from all other organisms in their general organization

The five-kingdom classification gives a clear indication of cellular organization and modes of nutrition, the characters which appeared very early in the evolution of life.

Anaerobic respiration is also used by multi-cellular organisms, like us, as a temporary response to oxygen-less conditions. During heavy or intensive exercise such as running, sprinting, cycling or weight lifting, our body demands high energy. As the supply of oxygen is limited, the muscle cells inside our body resort to anaerobic respiration to fulfill the energy demand.

Electron transport system is an integral part of the cellular respiration. Electrons are passed to oxygen through electron carriers which results in the formation of H2O. Electron carriers fall into three categories here.

(A) Electron Acceptors

NAD (Nicotinamide adenine dinucleotide) and FAD (Flavin adenine dinucleotide) both accept electrons and get reduced to NADH+H+ and FADH2.

This occurs during process glycolysis, oxidative decarboxylation of pyruvic acid and Krebs’ cycle.

(B) Respiratory Coenzyme Complexes

Complex I - NADH dehydrogenase: It oxidises NADH+ H+ and receives electrons or H+ ions from NADH+H+. These electrons are then passed to the mobile electron carrier ubiquinone.

Complex II - Succinate dehydrogenase: It oxidises FADH2 and the release electrons are sent to the mobile electron carrier ubiquinone.

Complex III - Cytochrome b + cytochrome c1: Cytochrome bc1 complex accepts electrons from ubiquinone and passes them to the mobile electron carrier cytochrome c.

Complex IV - Cytochrome a, a3: Complex IV accepts electrons from cytochrome c and passes them to oxygen. Oxygen acts as a final hydrogen or electron acceptor. Oxygen when combines with two protons it forms a molecule of water.

(C) Mobile Electron Carriers

Ubiquinone: It is a carrier between complex I and complex II. It transfers electrons from NADH to complex III.

Cytochrome c: It is a carrier between complex II and complex III. It transfers electrons to complex IV.

The wavelength of the light and the magnification of the microscope is inversely proportional which means the longer the wavelength, the less the magnification and vice versa. The magnification defines the how closer the object is viewed. Microscope resolution is also impacted by the wavelength of light being used to illuminate the specimen. Longer wavelengths of light offer less resolution than short wavelength illumination. ... As light slows down the wavelength gets shorter and yields better resolution.

Auxins prevent premature leaf and fruit fall.

NAA prevents fruit drop in tomato; 2,4-D prevents fruit drop in Citrus

Auxins prevent premature leaf and fruit fall.

NAA prevents fruit drop in tomato; 2,4-D prevents fruit drop in Citrus

The records of population density 2011 of India state that the density 2011 has increased from a figure of 324 to that of 382 per square kilometer. Bihar is the most thickly populated state (1106 persons/sq km.) followed by west bengal-1028 and Kerala 860. Population density increased at the rate of 17.54 from 2001 to 2011. Density of population in India is 382 persons per sq km. Delhi (11,320) turns out to be the most densely inhabited followed by Chandigarh (9,258), among all States/UTs, both in 2001 and 2011 Census.

A floral formula is a system of representing the structure of a flower using specific letters, numbers and symbols. It represents floral symmetry, number of parts, connation and adnation, insertion, and ovary position. Floral formulas are useful tools for remembering characteristics of the various angiosperm families.  Their construction requires careful observation of individual flowers and of variation among the flowers of the same or different individuals.

A floral formula consists of five symbols indicating from left to right:

• Floral Symmetry
• Number of Sepals
• Number of Petals
• Number of Stamens
• Number of Carpels

The following symbols are used in floral formulae:

Some important points to be remembered while writing floral formulae:

• Fusion is indicated by enclosing the figure in brackets.
• Adhesion is indicated by drawing a line above the symbols of the floral parts.
• The position of the mother axis with respect to the flower is represented by drawing a dot on the top of the floral diagram.

Floral formulae of some important families of flowering plants:

Family Fabaceae:

Family Solanaceae

Family

Liliaceae

Morphology

• Earthworms have long cylindrical body divided into 100-120 similar short segments known as metameres .
• The dorsal surface of the body is marked by a dark median mid dorsal line along the longitudinal axis of the body and the ventral surface is distinguished by the presence of genital openings.
• Anterior end consists of the mouth and the prostomium, covering the mouth.
• The first body segment is called the peristomium, which contains the mouth.
• In a mature worm, segments 14-16 are covered by a prominent dark band of glandular tissue called clitellum, thus dividing the body into preclitellar, clitellar and postclitellar segments.
• Four pairs of spermathecal apertures and a pair of male genital pores are situated on the 5th -9th segments and 18^th segment, respectively.
• A single female genital pore is present in the mid-ventral line of 14th segment.
• Numerous minute pores called nephridiopores open on the surface of the body.
• Except the first, last and clitellum, there are rows of S-shaped setae in each segment, help in locomotion.

Nephridia are segmentally arranged coiled tubules which act as excretory organs in the earthworms. It performs the following function:
i. Regulate the volume and composition of the body fluids .
ii. Collects excess fluid from the coelomic chamber.
iii. Delivers the wastes through a pore to the surface in the body wallinto the digestive tube.

Ratio of the density of a substance to the density of water at 4° C is called specific gravity of the substance.

Conducting part – This is the part from the nostrils to the terminal bronchioles. The conducting part has the following functions –

• Transport atmospheric air to the alveoli.
• Clear the air from foreign particles.
• Humidify the air.
• Bring the air to body temperature.

Ultrafiltration (UF) is a membrane filtration process similar to Reverse Osmosis, using hydrostatic pressure to force water through a semi-permeable membrane. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane. Ultrafiltration is an effective means of reducing the silt density index of water and removing particulates that can foul reverse osmosis membranes. Ultrafiltration is frequently used to pretreat surface water, seawater and biologically treated municipal water upstream of the reverse osmosis unit.

Anterior pituitary

• Adrenocorticotrophic hormone (ACTH)
• Thyroid-stimulating hormone (TSH)
• Luteinising hormone (LH)
• Follicle-stimulating hormone (FSH)
• Prolactin (PRL)
• Growth hormone (GH)
• Melanocyte-stimulating hormone (MSH)

Posterior pituitary

• Anti-diuretic hormone (ADH)
• Oxytocin

Chloroplast, peroxisome and mitochondria are three cellular organelles involved in photorespiration.
Various steps of photorespiratory pathway:
(a) In presence of high Oz, RuBP carboxylase acts as oxygenase and results in formation of 3PGA (Phosphoglyeric acid) and 2-phosphoglycolate, 2-phosphoglycolate loses PO4 group to make glycolate.
(b) Synthesized glycolate in chloroplast enters into peroxisomes.

© The glycolate is oxidised into glyoxylate and H2O2 by oxidase enzyme.
(d) Glyoxylate is changed into glycine (amino acid) by glutamate glyoxylate transaminase (enzyme).
(e) Two molecules of glycine form serine and one mol. of CO2 in mitochondria but no ATP and NADPH are formed.
(f) Finally serine passes into mitochondria and is changed into carbohydrate (3 carbon) and Phosphoglycolate (2 carbon).
(g) Soon glycolate is formed of phosphoglycolate. In peroxisomes, glycolate soon changes into glycine and glycine into serine and CO2, without production of assimilatory powers (ATP and NADPH2).

Mitochondria are organs of special importance. These organelles are absolute requirements to sustain the physiological activities of the cells.
1. They are typically sausage shaped or cylindrical shaped.
2. Each mitochondrion is a double membrane - bound structure with the outer membrane and the inner membrane dividing its lumen distinctly into two compartments, I.e., the outer compartment (perimitochindrial space) and the inner compartment matrix).
3. They are present in almost all the cells of the body except in Red Blood Cells.
4. They are freely floating in the cytoplasm and and stay in the regions of high energy requirement.
5. Mitochondria are self replicable i.e. they can multiply on their own without the requirement of cell to divide.
This characteristic feature helps replacement of old, worn out and damaged mitochondria with new and healthy mitochondria.
6. Mitochondria have their own genetic material as single stranded DNA.
7. The mitochondria have many enzyme complex which in series help in formation of energy i.e. adenosine tri-phosphate (ATP).

In prokaryotes, which lack a nucleus, cytoplasm simply means everything found inside the plasma membrane. One major component of the cytoplasm in both prokaryotes and eukaryotes is the gel-like cytosol, a water-based solution that contains ions, small molecules, and macromolecules. Prokaryotic cells are surrounded by a plasma membrane, but they have no internal membrane-bound organelles within their cytoplasm. The absence of a nucleus and other membrane-bound organelles differentiates prokaryotes from another class of organisms called eukaryotes.