Electron Transport Chain (ETC) (Terminal oxidation)
(i) During glycolysis, link reaction and Krebs cycle the respiratory substrates are oxidized at several steps and as a result many reduced coenzymes NADH + H⁺ and FADH₂ are produced.
(ii) These reduced coenzymes are transported to inner membrane of mitochondria and are converted back to their oxidized forms produce electrons and protons.
(iii) In mitochondria, the inner membrane is folded in the form of finger projections towards the matrix called cristae.
(iv) In cristae many oxysomes (F₁ particles) are present which have electron transport carriers are present.
(v) According to Peter Mitchell's Chemiosmotic theory this electron transport is coupled to ATP synthesis. Electron and hydrogen(proton) transport takes place across four multiprotein complexes(I-IV). They are:
a) Complex-I (NADH dehydrogenase)
(i) It contains a flavoprotein(FMN) and associated with non-heme iron Sulphur protein (Fe-S). This complex is responsible for passing electrons and protons from mitochondrial NADH (Internal) to Ubiquinone(UQ).
\(\mathrm{NADH}+\mathrm{H}^{+}+\mathrm{UQ} \rightleftharpoons \mathrm{NAD}^{+}+\mathrm{UQH}_{2}\)
(ii) In plants, an additional NADH dehydrogenase (External) complex is present on the outer surface of inner membrane of mitochondria which can oxidise cytosolic NADH + H⁺.
(iii) Because mitochondrial inner membrane cannot allow NADH molecules directly in to the matrix. Ubiquinone (UQ) or Coenzyme Quinone (CoQ) is a small, lipid soluble electron, proton carrier located within the inner membrane of mitochondria.
b) Complex-II (Succinic dehydrogenase)
(i) It contains FAD flavoprotein is associated with non-heme iron Sulphur (Fe-S) protein.
(ii) This complex receives electrons and protons from succinate in Krebs cycle and is converted into fumarate and passes to ubiquinone.

c) Complex-III (Cytochrome bc₁ complex)
(i) This complex oxidises reduced ubiquinone (ubiquinol) and transfers the electrons through Cytochrome bc₁ Complex (Iron Sulphur center bc₁ complex) to cytochrome c.
(ii) Cytochrome c is a small protein attached to the outer surface of inner membrane and act as a mobile carrier to transfer electrons between complex III to complex IV.
\(\mathrm{UQH}_{2}+2 \mathrm{CytC}_{\text {oxidised }} \rightleftharpoons \mathrm{UQ}+2 \mathrm{Cytc}_{\text {reduced }}+2 \mathrm{H}^{+}\)
d) Complex IV (Cytochrome c oxidase)
(i) This complex contains two copper centers (A and B) and cytochromes a and a₃. Complex IV is the terminal oxidase and brings about the reduction of 1/2 O₂ to H₂O.Two protons are needed to form a molecule of H₂O (terminal oxidation).
\(2 \mathrm{CytC}_{\text {oxidised }}+2 \mathrm{H}^{+}+1 / 2 \mathrm{O}_{2} \rightleftharpoons 2 \mathrm{CytC}_{\text {reduced }}+\mathrm{H}_{2} \mathrm{O}\)
(ii) The transfer of electrons from reduced coenzyme NADH to oxygen via complexes I to IV is coupled to the synthesis of ATP from ADP and inorganic phosphate (Pi) which is called Oxidative phosphorylation.
(iii) The F₀F₁- ATP synthase (also called complex V) consists of F₀ and F₁. F₁ converts ADP and Pi to ATP and is attached to the matrix side of the inner membrane.
(iv) F₀ is present in inner membrane and acts as a channel through which protons come into matrix.

(i) C₄ cycle/Di - carboxylic acid pathway/ Di - carboxylation pathway is an adaptive mechanism.
(ii) It takes place in two phases. First phase takes place in stroma of mesophyll cells, where the CO₂ acceptor molecule 3-Carbon compound, phosphoenol pyruvate (PEP) to form 4-carbon oxalo acetic acid (OAA). The first product is a 4-carbon and so it is named as C₄ cycle. Oxalo acetic acid is a dicarboxylic acid and hence this cycle is also known as dicarboxylic acid pathway.
(iii) Carbondioxide fixation takes place in two places one in mesophyll and another in bundle sheath cell.
(iv) C₄ plants requires 5 ATP and 2NADPH + H⁺ to fix one molecule of CO₂.

Stage: I Mesophyll Cells

(i) Oxaloacetic acid (OAA) is converted into malic acid or aspartic acid and is transported to the bundle sheath cells through plasmodesmata.
Stage: II Bundle Sheath Cells
(i) Malic acid undergoes decarboxylation and produces a 3 carbon compound Pyruvic acid and CO₂.
(ii) The released CO₂ combines with RUBP and follows the calvin cycle and finally sugar is released to the phloem.
(iii) Pyruvic acid is transported to the mesophyll cells.

1. In the lysogenic cycle the phage DNA gets integrated into the DNA of the host cell and gets multiplied along with nucleic acid of the host. No independent viral particle is formed.
2. As soon as the phage injects its linear DNA into the host cell it becomes circular and integrates into the bacterial chromosome by recombination. The integrated phage DNA is now called prophage.
3. The activity of the prophage gene is repressed by two repressor proteins which are synthesized by phage genes. This checks the synthesis of new phages within the host cell.
4. However, each time the bacterial cell divides, the prophage multiplies along with the bacterial chromosome.
5. On exposure to UV radiation and chemicals the excision of phage DNA may occur and results in lytic cycle.

(i) No. there is no scientific proof for this statement. During day time photosynthesis takes place oxygen is evolved.
(ii) This reaction requires light hence the above statement is incorrect.

(i) Blood is a typical fluid connective tissue because it functions as the transport medium for the cardiovascular system.
(ii) Eg: Transport of nutrients and wastes and transport of respiratory gases throughout the body.

(i) In the gastrula stage of embryo on the root of gastrocoel an archenteron is formed.
(ii) Archenteron develops chordodorsatis or notochord dorsally.
(iii) Its anterior end forms brain and posterior axis form spinal cord.
Eg: Hemichordates and chordates.

The circulatory system is of two types,
1. Open type: The blood remains filled in tissue spaces due to the absence of blood capillaries.
Eg: Arthropods, Molluscs, Echinoderms, and Urochordates
2. Closed type: The blood Is circulated through blood vessels of varying diameters (arteries, veins, and capillaries)
Eg: Annelids, Cephalochordates and Vertebrates.

(i) All the vertebrates commonly have dorsal nervous system
(ii) At the stage of development they have blastopore of embryo
(iii) Heart is developed ventrally
(iv) All vertebrates are three layered
(a) Ectoderm
(b) Mesoderm and
(c) Endoderm
(v) All verteberates are bilaterians
(vi) All verteberates are enterocoelomates

1. There are many organisms, which never reproduce in their life, although all other characteristics of living things are present in them.
2. Eg: Sterile worker bees, mules, infertile human couples etc.,
3. Hence reproduction cannot be an all-inclusive defining property of living things.

A virus cannot grow on non-living culture medium because it needs living cells for its metabolism and multiplication. They are obligate parasites.

1. Reproduction is required for the perpetuation of a population.
2. It is not necessary for the survival of living organisms.
3. Many organisms. Eg: Mules, Sterile worker bees, infertile human couples are not able to reproduce, while they have all other defining properties of life, so they can be called as Living

S.No	Bacteria	Higher plants
1	H2S is hydrogen donor.	H2O is hydrogen donor.
2	Oxygen is not evolved	Oxygen is evolved
3	Chlorobium Chlorophyll is an example of pigment	Chlorophylls are the pigments involved in photosynthesis.

Though viruses are harmful, viruses of Baculoviridae groups are commercially used as insecticides. Hence viruses act as biopesticides. Eg : Entomopox viruses

The integrated phage DNA (Prophage) activity is suppressed by repressor proteins which checks the synthesis of new phage.

1.The cnidaria is aquatic, radially symmetrical, and diploblastic.
2. The tentacles have stinging cells called cnidocytes or cnidoblasts or nematocysts.
3. They exhibit tissue level of organization.
4. They have a central gastrovascular cavity called coelenteron.
5. Digestion is both extracellular and intracellular.
6. Alternation of generation is seen in cnidarians which have polyp and medusa forms.
7. Development is indirect with planula larva e.g. Physalia.

S.No. Prokaryotes Eukaryotes 1. Unicellular Unicellular or multicellular 2. Lack membrane bound nuclei Possess well defined nucleus 3. Membrane bound organelles are absent. E.g., Bacteria. Membrane bound organelles are present. E.g., Amoeba.

1. These bacteria require oxygen as terminal acceptor and will not grow under anaerobic conditions (i.e. in the absence of O2) Example: Streptococcus Obligate aerobes of bacteria.
2. Some Micrococcus species are obligate aerobes (i.e. they must have oxygen to survive).

1. The bacterial chromosome is, a single circular DNA molecule, tightly coiled and is not enclosed in a membrane as in Eukaryotes.
2. This genetic material is called Nucleoid or Genophore. It is amazing to note that the DNA of E.coli which measures about Imm long when uncoiled, contains all the genetic information of the organism.
3. The DNA is not bound to histone proteins. The single chromosome or the DNA molecule is circular and at one point it is attached to the plasma membrane and it is believed that this attachment may help in the separation of two chromosomes after DNA replication.

1) Classification is essential to achieve following needs.
2) To relate things based on common characteristic features.
3) To define organisms based on the salient features. 
4) Helps in knowing the relationship amongst different groups of organisms.
5) It helps in understanding the evolutionary relationship between organisms.

1. Phage (T4) particles interact with cell wall of host (E.coli). The phage tail makes contact between the two, and tail fibres recognize the specific receptor sites present on bacterial cell surface.
2. The lipopolysaccharides of tail fibres act as receptor in phages.

1. Growth is an intrinsic property of all living organisms through which they can Increase cells both in number and mass.
2. Unicellular and multicellular organisms grow by cell division.
3. In plants, growth is indefinite and occurs throughout their life.
4. In animals, growth is definite and occurs for some period.
5. However, cell division occurs in living organisms to repair and heal the worn out tissues.

Because carbohydrates are partially oxidised to organic acid, particularly malic acid without corresponding release of CO₂ but O₂ is consumed. Hence the RQ value will be zero.
\(\underset { Glucose }{ 2{ C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 }+3{ O }_{ 2 }\rightarrow } \underset { malic\quad acid }{ 3{ C }_{ 4 }{ H }_{ 6 }{ O }_{ 5 }+3{ H }_{ 2 }O+Energy } \)
RQ of glucose in succulents = \(\frac { Zero \ molecule \ of \ { CO }_{ 2 } }{ 3 \ molecules \ of \ { CO }_{ 2 } } \) = 0 (Zero)

Tissues are organized in specific proportions and patterns to form organs like lungs, heart, stomach, kidneys, ovaries, testes etc. Hence the tissues are called the 'living fabrics'.

Excretory organ	Animal
1. Flame cells /Solenocytes	Flatworms
2. Nephridia	Annelids
3. Malpighian tubules	Insects
4. Kidneys	Vertebrates
5. Green glands	Crustaceans

[Ans.(a)]

a. Sea anemone
b. Radial symmetry
c. Not cephalized
d. Two
e. A single
f. Yes

Penicillium - Conidia formation.
A- Conidium
B - Conidiophore

1. Pili or Fimbriae are hair like appendages found Discuss. on surface of cell wall of gram-negative bacteria.
Eg: Enterobacterium.
2. The pili are 0.2 to 20 11m long with a diameter of about 250A
3. In addition to normal pili there are special type of pili which help in conjugation called sex pili are also found.

Generally viruses are of three types based on shape and symmetry
1. Cuboid symmetry - Eg: Adenovirus, Herpes virus.
2. Helical symmetry - Eg: Influenza virus, TMV.
3. Complex or Atypical symmetry - Eg: Bacteriophage, Vaccinia virus.

S.No	Prokaryotic	Eukaryotic
1.	Unicellular Organisms	Unicellular or multicellular organisms
2.	Lack membrane bound nucleus	Definite nucleus is present bound by nuclear membrane
3.	Organelles like mitochondria, endoplasmic reticulum are absent.	Organelles like mitochondria, endoplasmic reticulum are present.
4.	Eg : Amoeba	Eg : Oedogonium