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Correct option (A) CO, N₂

Explanation:

CO and N₂ are isoelectronic because both have 14 electrons.

Correct option is (a) 1

Let, the oxidation state of Fe in [Fe(H₂O)₅(NO)] SO₄ be x.

∴ x + 5 (0) + 1 = + 2

⇒ x = + 1

Answer is : (b) Evolution is goal-oriented

Evolution is not goal oriented. Evolution simply depends on the environment, which the organisms live and try to survive. The environment is fit for strongest individual who can survive and reproduce. Evolution uses the theory of natural selection where there is variation. We have variations of traits, heredity and different reproductive strategies as a result of natural selection.

Answer is : (a) Sucrose

The sucrose is actively transported against its concentration gradient into the phloem cells using the electrochemical potential of the proton gradient. This is coupled to the uptake of sucrose with a carrier protein called the sucrose-H⁺ symporter.

Answer is : (a) Golgi bodies

A secretory cell would need secretory enzymes and glycoproteins required in secretions, which are produced in Golgi bodies.

Answer is : (a) a molecule of carbon dioxide is accepted

Riboluse 1,5-Biphosphate (RuBP) is the first acceptor of CO₂ in the formation of two molecules of 3-Phosphoglyceraldehyde (PGA) during the Calvin cycle of photosynthesis.

Answer is : (a) creepers

Horizontal stem of creepers often develop adventitious roots from the nodes. Adventitious roots are the roots which arise from an organ other than a root. They generally develop from stem nodes, internodes, leaves, etc.

The Correct option is  (B) 40° < i < 50°

Correct option is (C)

The graph (c) is correct as, it shows the highest biochemical activity in the lysosomes. These are membrane bound organelles which contain enzymes that degrade polymers into their monomeric subunits, i.e. hydrolytic enzymes.

Answer is : (a) P-iv, Q-iii, R-i, S-ii

HIV is the causative organism for AIDS.

Syphilis is a bacterial infection caused by Treponema sp. It spreads by sexual contact that starts as a painless sore. Viral hepatitis caused by HBV is an infection that causes liver inflammation and damage organs.

Gonorrhoea is caused by Neisseria sp. It is sexually transmitted bacterial infection that if let untreated may cause infertility.

Answer is : (b) telocentric

Telocentric chromosome is a chromosome like a straight rod with the centromere in terminal position.

Metacentric chromosome is a X-shaped chromosome, with the centromere in the middle so that the two arms of the chromosomes are almost equal.

Acrocentric chromosome is a chromosome in which the centromere is located quite near one end of the chromosome.

Sub-metacentric chromosome is a chromosome whose centromere is located near the middle.

Correct option  (B) decrease

Explanation:

Humidity of atmosphere is inversely proportional to transpiration (water flow). Increase in humidity will decrease the water flow in the xylem. 

Correct option  (C) Single-stranded RNA 

Explanation:

Ebola virus consist of ss RNA. 

Correct option (D) Oxygen

Explanation:

Oxygen is the terminal acceptor of electrons in mitochondrial ETS. 

Correct option  (A) Tube 'P' contains sugar; tube 'Q' contains protein 

Explanation:

→ Nitric acid reacts with proteins to form yellow nitrated products

 → Benedict test is used to test the presence of monosaccharide and reducing sugar. 

Answer is : (c) Centriole

Centriole is not found in plant cells, it is found only in animal cells. These paired organelles are typically located together near the nucleus in the centrosome, a granular mass that serves as an organising centre for microtubules. Centriole is involved in the development of spindle fibres in cell division.

Answer is : (a) neuron

The brain and spinal cord are made up of many cells, including neurons and glial cells. Neurons are cells that send and receive electro-chemical signals for pain or pleasure to and from the brain and nervous system.

● Blastocyst is a structure formed in the early development of mammals. It possesses an Inner Cell Mass (ICM) which subsequently forms the embryo.

● Histoblast is a cell or cell group possessing broad histogenetic capacity, i.e. capable of forming tissue.

● Haemocyte is a cell of the haemolymph of various invertebrates, especially arthropods.

Answer is : (a) thyroxine

Iodine is found in thyroxine. Thyroxine, also called 3, 5, 3', 5'-tetraiodothyronine or T₄, is one of the two major hormones secreted by the thyroid gland (the other is triiodothyronine). Thyroxine’s principal function is to stimulate the consumption of oxygen and thus the metabolism of all cells and tissues in the body. Thyroxine is formed by the molecular addition of iodine to the amino acid tyrosine while the latter is bound to the protein thyroglobulin.

Answer is : (b) density

Lactometer is a device used for testing the purity of milk. It measures relative density of milk with respect to water, which is also called specific gravity. If the specific gravity of a sample of milk is within the approved ranges, the milk is pure. If it is not, then there is some adulteration in milk.

Answer is : (b) hypotonic solution

When mammalian liver cells are kept in a hypotonic solution, endosmosis occurs as the cell is hypertonic. Due to the endosmosis, the cellular protoplasm is filled with water, it swells and the cells become turgid. Swelling is seen because the water flows from lower concentration of solute to the higher concentration of solute.

Answer is : (d) epithelial cells

Carcinoma is a category of types of cancer that develops from epithelial cells. Lymphoma is the cancer that occurs in lymph cells. Leukemia is blood cancer that originates in the blood and bone marrow. Mesoderm is one of the germ layer from which skeletal muscle, bone, connective tissue, heart and the urogenital system originate.

Answer is : (c) 4

The haemoglobin molecule has four binding sites for oxygen molecules. Thus, each Hb tetramer can bind four oxygen molecules. Haemoglobin is the oxygen transporting protein of red blood cells and is a globular protein with quaternary structure. Haemoglobin consists of four polypeptide subunits, 2α chains and 2β chains.

Answer is : (d) corpus callosum

Corpus callosum is nervous band which attaches both cerebral hemispheres of mammals. It is a thick band of nerve fibres that divides the cerebral cortex lobes into left and right hemispheres. It connects the left and right sides of the brain allowing for communication between both hemispheres.

Correct option (D) corpus callosum 

Explanation:

Corpus callosum is nervous band attaches both cerebral hemispheres of mammals. 

Answer is : (a) BeCl₂ < MgCl₂ < CaCl₂ < BaCl₂

The ionic character is decided by Fajan’s rule. According to this rule, larger is size of cation, smaller the size of the anion and lesser is the charge on the cation or high, thus more will be the ionic character. As the anion and charge of n the cation in all the given compounds are same. So, the ionic character is only dependent on the size of cation. As the size of cation increases in the order

Be²⁺ < Mg²⁺ < Ca²⁺ < Ba²⁺

∴ The ionic character will also increase in the same manner, i.e.

BeCl₂ < MgCl₂ < CaCl₂ < BaCl₂

Correct option is (b) Flow of smoke is initially laminar, then turbulent

As smoke rises up in air, speed of smoke increases and flow becomes turbulent

Correct option (D) Lipids and membrane proteins do not provide structural and functional asymmetry 

Explanation:

Proteins provide asymmetry to plasma membrane, as they are of 2 types i.e. peripheral and integral.

Correct option (D) Water and octane

Explanation:

Hydrogen bond is a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in another molecule. This is not possible in case of water and octane

Correct option  (B) Glucose + galactose 

Explanation:

Lactose + Lactase → Glucose + Galactose

Correct option (C) Mitochondria and cytoplasm

Explanation:

Respiratory Reactions 

Glycolysis → Cytoplasm 

 Kreb cycle and ETS → Mitochondria

Answer is : (c) Human, chimpanzees and gorillas evolve from a common ancestor

The correct statement for primates’ evolution is that human, chimpanzees and gorillas share a common ancestor. From fossil records, primatologists came to know that human, chimpanzee and gorilla are evolved from a common ancient ancestor about 10 million years ago. Recent studies on gorilla genome confirmed that gorilla diverged from the common ancestor about 6 million years ago.

Correct option(A) concave lens

Explanation:

Image is formed before retina in short sightedness

Answer is : (a) filtration of blood constituents

In Bowman’s capsule ultrafiltration of blood occurs. Bowman’s capsule is a cup-like sack at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. Fluids from blood in the glomerular are collected in the Bowman’s capsule (i.e. glomerular filtrate) and further processed along the nephron to form urine. This process is known as ultrafiltration.

Answer is : (a) concave lens

Short-sightedness (myopia) is corrected by using concave lens. These lens work by bending the light rays slightly outwards, so that they can focus further back on the retina.

Myopia is an eye defect in which the eyeball grows slightly too long. This means that light does not focus on the light sensitive tissue (retina) at the back of the eye properly. Instead, the light rays focus just in front of the retina, resulting in distant objects appearing blurred.

Answer is : (a) parietal lobe of cerebrum

Parietal lobe is sensory lobe for touch, pain and temperature. The cerebral cortex is divided into four sections, called ‘lobes’. Out of these, the parietal lobe is associated with movement, orientation, recognition and perception of stimuli. Thus, the parietal lobe functions in registration of sensory perception of touch, pain, heat and cold, knowledge about position in space, taking in information from environment, organising it and communicating to rest of brain.

Answer is : (a) homologous chromosomes; sister chromatids

Meiosis-I Reduction division (2n → n), separation of homologous chromosomes results in reduction of chromosome ploidy to half.

Meiosis-II Similar to mitosis where sister chromatids separate.

Correct option(B) virus

Explanation:

Virus multiplies only in living cells

Answer is : (b) virus

Virus cannot be cultured in an artificial medium. It multiples only in living cells. Viruses are obligate intracellular parasites.

They lack metabolic machinery to generate energy or to synthesise proteins, instead they rely on their host cells to carry out these functions

Answer is : (d) Cornea

The cornea acts as the eye’s outer most lens. It functions like as window that controls and focusses the entry of light into the eye (visual perception). The cornea contributes between 65-75 per cent of the eye’s total focussing power. When light strikes the cornea, it bends or refracts the incoming light on to the lens. The cornea covers the pupil (the opening at the centre of the eye), iris (the coloured part of the eye), and anterior chamber (the fluid filled inside of the eye).

Correct option (A) The sense cells of the cochlea

Explanation:

Auditory cranial nerve has two branches 

(i) Vestibular nerve : for equilibrium.

(ii) Cochlear nerve : for hearing. 

Correct option (D) Mitochondria and Chloroplast

Explanation:

Mitochondria and chloroplast have endo-symbiotic origin (prokaryotic type). So, have ds circular DNA as that of prokaryotes  

Correct option (B) H₂O is oxidized and CO₂ is reduced

Explanation:

In photosynthesis 

Light Reaction → Photolysis of water (H₂O is oxidised) 

 Dark Reaction → CO₂ is reduced for sugar formation 

Correct option (B) brain

Explanation:

A reflex action does not involve brain 

Note : Only cranial reflex completed by medulla oblongata (which is a small part of brain)  

Correct option  (B) Nitrogen

Explanation:

Insectivorous plants grow in Nitrogen deficient soils and in order to compensate the deficiency they catch and digest insects and obtain N from chitin (NAG). 

Answer is : (b) Nitrogen

Insectivorous plants mostly thrive in marshes and rocky outcrops or other nitrogen poor areas where sunlight and water are abundant. These plants have evolved the ability to trap and digest insects, which are an excellent source of nitrogen as they contain around 10% nitrogen by mass. Insectivorous plants are able to obtain between 10-80% of their total nitrogen from insects.

Correct option  (B) asymmetric characteristic of the inter atomic potential energy curve of the solid

Explanation:

Thermal expansion of a solid is due to asymmetric characteristic of inter atomic potential energy curve of the solid.

Answer is : (b) 64.3 cm

Length of pendulum = Length of thread + Radius of bob

= 63.2+2.256/2 = 63.2+1.128

= 64.328 cm

But now the student must apply rule for taking significant digits in a measurement.

In addition or subtraction,

Number of digits after decimal in result = Least number of digits after decimal in quantities added

So, length of pendulum = 64.3 cm.

Answer is : (c) either father or mother is Rh⁺

In humans, Rhesus condition can arise when either father or mother is Rh positive. Rhesus (Rh) factor is an inherited protein found on the surface of red blood cells. If an individual’s blood has the protein, he/she is Rh positive and if his/her blood lacks the protein, he/she is Rh negative. A baby may have the blood type and Rh-factor of either parent or a combination of both parents. Rh factor follows a common pattern of law of dominance because Rh-positive gene is a dominant gene.

Seedlings grown in dark are taller than those grow in light.

In humans, Rhesus conditions can arise when father is Rh⁺ and mother is Rh^–