Biology

With regard to the Biological Nitrogen Fixation by Rhizobium in association with soybean, which one of the following statement/ statements do not hold.
a. Nitrogenase may require oxygen for its functioning.

b. Nitrogenase is MO- Fe protein

c. Leg-haemoglobin is a pink coloured pigment.

d. Nitrogenase helps to convert N2 gas into two molecules of ammonia.

Solution: Nitrogenase is an enzyme that does not require oxygen to function. All nitrogen-fixing bacteria, on the other hand, have a specific structure called heterocysts that generate an anaerobic...

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Which one of the following symptoms is not due to manganese toxicity in plants?
a. Calcium translocation in shoot apex is inhibited

b. Deficiency in both Iron and Nitrogen is induced

c. The appearance of brown spot surrounded by chlorotic veins

d. None of the above

Solution: Due to an induced iron deficit, manganese toxicity commonly causes chlorosis (pale or yellow color), which is most severe on the younger leaves. In crops afflicted by manganese poisoning,...

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Deficiency symptoms of an element tend to appear first in young leaves. It indicates that the element is relatively immobile. Which one of the following elemental deficiency would show such symptoms?
a. sulphur

b. magnesium

c. nitrogen

d. potassium

Solution: Symptoms of an element deficiency usually occur first in young leaves. It suggests that sulfur is a relatively stationary element. Option (a) is the answer. So, the correct answer is...

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Which one of the following statements can best explain the term critical concentration of an essential element?
a. essential element concentration below which plant growth disregarded.

b. essential element concentration below which plant growth becomes stunted.

c. essential element concentration above which plant remains in the vegetative phase.

d. none of the above

Solution: The phrase "critical concentration" is used to describe the concentration of vital components below which plant growth is slowed or halted. In addition, if the concentrations of vital...

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Which one of the following roles is not characteristic of an essential element?
a. is a component of biomolecules

b. changing the chemistry of soil

c. being a structural component of energy-related chemical compounds

d. activation or inhibition of enzymes

Solution: It is easier to change a dirt's fruitfulness, which is a significant property than it is to change the dirt's physical features. The presence of dirt minerals, as well as seepage...

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7. Mitosis results in producing two cells which are similar to each other. What would be the consequence if each of the following irregularities occur during mitosis?
a. Nuclear membrane fails to disintegrate

b. Duplication of DNA does not occur

c. Centromeres do not divide

d. Cytokinesis does not occur

Solution: (a) The spindle fibers would be unable to reach chromosomes if the nuclear membrane failed to dissolve. As a result, chromosomes would be unable to reach the cell's opposite poles. (b) If...

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The following events occur during the various phases of the cell cycle, Name the phase against each of the events.
a. Disintegration of nuclear membrane_________________________

b. Appearance of nucleolus_________________________

c. Division of centromere_________________________

d. Replication of DNA _________________________

Solution: The following are the events and their phases. (a)Disintegration of nuclear membrane - Prophase. (b) Appearance of nucleolus -Telophase. (c) Division of centromere - Anaphase. (d) ...

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While examining the mitotic stage in a tissue, one finds some cells with 16 chromosomes and some with 32 chromosomes. What possible reasons could you assign to this difference in chromosome number? Do you think cells with 16 chromosomes could have arisen from cells with 32 chromosomes or vice versa?

Solution: The most possible reason for this phenomenon is mosaicism. Mosaicism refers to the coexistence of two populations of cells with different genotypes in a single person. Mosaicism can occur...

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In which phase of meiosis is the following formed? Choose the answers from hint points given below.
a. Synaptonemal complex ____________________________

b. Recombination nodules ____________________________

c. Appearance/activation of ____________________________ enzyme recombinase

d. Termination of chiasmata _ ___________________________

e. Interkinesis ____________________________

f. Formation of dyad of cells _ ___________________________

Hints : 1) Zygotene, 2) Pachytene, 3) Pachytene, 4) Diakinesis, 5) After Telophase-I /before Meosis-II, 6) Telophase-I /After Meiosis-I.

Solution: During meiosis, a protein structure called the synaptonemal complex (SC) arises between homologous chromosomes (two pairs of sister chromatids) and is visible in the zygotene stage because...

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Identify the wrong statement about meiosis
a. The pairing of homologous chromosomes

b. Four haploid cells are formed

c. At the end of meiosis, the number of chromosomes is reduced to half

d. Two-cycle of DNA replication occurs

Solution: Meiosis is a type of cell division in which the number of chromosomes is cut in half, resulting in four haploid cells. DNA replication is followed by two rounds of cell division in...

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Which of the events listed below is not observed during mitosis?
a. Chromatin condensation

b. Movement of centrioles to opposite poles

c. The appearance of chromosomes with two chromatids joined together at the centromere.

d. Crossing over

Solution: The parent cell's replicated chromosomes condense and become thousands of times more compact during prophase than they were during interphase. These structures now look like X-shaped...

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Which of the events listed below is not observed during mitosis?
a. Chromatin condensation

b. Movement of centrioles to opposite poles

c. The appearance of chromosomes with two chromatids joined together at the centromere.

d. Crossing over

Solution: The parent cell's replicated chromosomes condense and become thousands of times more compact during prophase than they were during interphase. These structures now look like X-shaped...

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Comment on the experimental setup. What does the setup demonstrate?
b. What will happen to the level of water if a blower is placed close to setup?

c. Will the mercury level fluctuate (go up/down) if phenylmercuric acetate is sprayed on leaves?

Solution: a) The setup depicts the transpiration pull, which is the force that occurs when the water pulls upwards from the root to the leaves. b) If a blower is installed near the setup, it will...

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Water molecule is very polar. Polar end of molecule attracts opposite charges on another water molecule (acts like a magnet). How will you explain this property of water with reference to the upward movement of water? Comment on the upward movement of water given the intermolecular hydrogen bonding in water.

Solution: The cohesion of the water molecules is the method through which water molecules remain linked to one another through hydrogen bonding. Water moves upward through xylem vessels, creating a...

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Minerals are present in the soil in sufficient amounts. Do plants need to adjust the types of solutes that reach the xylem? Which molecules help to adjust this? How do plants regulate the type and quantity of solutes that reach xylem?

Solution: Yes, the type and quantity of solutes that reach the xylem must be adjusted by plants. End dermal cell transport proteins aid in the maintenance and adjustment of solute transportation....

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Observe the diagram and answer the following;
a. Are these types of guard cells found in monocots or dicots?

b. Which of these shows a higher water content (i) or (ii)?

c. Which element plays an important role in the opening and closing of stomata?

Solution: a) Because dicots have a bean-shaped morphology, these guard cells are seen in dicots. It's commonly dumble-shaped for monocots. b) Figure i) depicts a higher water content. c) Potassium...

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When a freshly collected Spirogyra filament is kept in a 10% potassium nitrate solution, it is observed that the protoplasm shrinks in size:
a. What is this phenomenon called?

b. What will happen if the filament is replaced in distilled water?

Solution: a) Exosmosis is the name for this occurrence.  b) If the filament is put in distilled water, the protoplasm becomes turgid again when water flows in and the shrunken protoplasm...

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Keep some freshly cut flowers in a solution of food colour. Wait for some time for the dye to rise in the flower, when the stem of the flower is held up in light, coloured strands can be seen inside. Can this experiment demonstrate which tissue is conducting water up the stem?

Solution: This experiment can show which tissue is responsible for transporting water up the stem. The presence of colored strands indicates that the food color has been carried upwards through the...

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Water is indispensable for life. What properties of water make it useful for all biological processes on the earth?
a) Water is a polar solvent due to which it is regarded as the ‘universal solvent’.
b) Water has a high specific heat capacity.

c) Water has low viscosity and high surface tension.

d) The density of water decreases below 4◦C.

e) Capillarity of water

Solution: a) All living creatures' essential substances are solutes that are dissolved in water and transferred from one location to another. b) Specific heat is defined as the amount of energy...

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Correct the statements
a. Cells shrink in hypotonic solutions and swell in hypertonic solutions.

b. Imbibition is a special type of diffusion when water is absorbed by living cells.

c. Most of the water flow in the roots occurs via the symplast.

Solution: a) Hypertonic solutions cause cells to shrink, while hypotonic solutions cause them to swell. b) Imbibition is a type of diffusion in which water is absorbed by living or dead cells. c)...

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Water moves up against gravity and even for a tree of 20m height, the tip receives water within two hours. The most important physiological phenomenon which is responsible for the upward movement of water is _______________________.

Solution: Transpiration pull Even for a 20-meter-tall tree, water travels up against gravity. Water is delivered to the tip within two hours. Transpiration pull is the most essential physiological...

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Based on the figure given below which of the following statements is not correct?
a. Movement of solvent molecules will take place from chamber A to B.

b. Movement of solute will take place from A to B.

c. Presence of a semipermeable is a pre-requisite for this process to occur.

d. The direction and rate of osmosis depend on both the pressure gradient and concentration gradient.

Solution: Option (b) is the answer. Because the water in chamber A contains fewer solute particles, the water potential in chamber A is higher, allowing the water molecules in chamber A to move more...

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Mycorrhiza is a symbiotic association of a fungus with root system which helps in
A. Absorption of water

B. Mineral nutrition

C. Translocation

D. Gaseous exchange

Options:

a. Only A

b. Only B

c. both A and B

d. both B and C

Solution: Option (c) is the answer. Fungal mycelia are found in the roots of several higher plants. Mycorrhiza is the name for such a relationship. It reflects a mutualistic (symbiotic) relationship...

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The process of guttation takes place
a. when the root pressure is high and the rate of transpiration is low.

b. when the root pressure is low and the rate of transpiration is high

c. when the root pressure equals the rate of transpiration

d. when the root pressure, as well as rate of transpiration, are high.

Solution: Option (a) is the answer. Guttation occurs in the absence of transpiration, particularly in low-light situations (early morning). While guttation causes water droplets to accumulate on the...

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The male and female reproductive organs of several pteridophytes and gymnosperms are comparable to floral structures of angiosperms. Attempt to compare the various reproductive parts of pteridophytes and gymnosperms with reproductive structures of angiosperms.

Reproductive parts of pteridophytes and gymnosperm ●Strobili/cone ●Microsporophyll ●Megasporophyll ●Microsporangium ●Megasporangium Reproductive structures of angiosperms ●Flower ●Stamen...

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Heterospory i.e., the formation of two types of spores – microspores and megaspores is a characteristic feature in the life cycle of a few members of pteridophytes and all spermatophytes. Do you think heterospory has some evolutionary significance in the plant kingdom?

●Heterospory development occurs in situ embryos .The embryo takes nutrition from the female gametophyte and which gives it better protection. ● Heterospory occurs due to the evolution of seed habit,...

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Each plant or group of plants has some phylogenetic significance concerning evolution: Cycas, one of the few living members of gymnosperms, is called the ‘relic of the past’. Can you establish a phylogenetic relationship of Cycas with any other group of plants that justifies the above statement?

●Cycas is the connecting link between Gymnosperms and pteridophytes .  ●They show some features which are the same as in  pteridophytes such as flagellated antherozoids, circinate ptyxis,...

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It is said that the elemental composition of living organisms and that of inanimate objects (like earth’s crust) are similar in the sense that all the major elements are present in both. Then what would be the difference between these two groups? Choose the correct answer from among the following:

a. Living organisms have more gold in them than inanimate objects b. Living organisms have more water in their body than inanimate objects c. Living organisms have more carbon, oxygen and hydrogen...

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Sugars are technically called carbohydrates, referring to the fact that their formulae are only multiple of C(H2O). Hexoses, therefore, have six carbons, twelve hydrogens and six oxygen atoms. Glucose is a hexose.Choose from among the following another hexose.

a. Fructose b. Erythrose c. Ribulose d. Ribose A)correct option -A B)Explanation of correct option - ●Fructose is a type of sugar known as a monosaccharide. ●Fructose is also known as “fruit sugar”...

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When you take cells or tissue pieces and grind them with an acid in a mortar and pestle, all the small biomolecules dissolve in the acid.Proteins, polysaccharides and nucleic acids are insoluble in mineral acid and get precipitated. The acid-soluble compounds include amino acids, nucleosides, small sugars etc. When one adds a phosphate group to a nucleoside, one gets another acid-soluble biomolecule called

a. Nitrogen base b. Adenine c. Sugar phosphate d. Nucleotide A)correct option -D B)Explanation of correct option - The basic building block of nucleic acids. A nucleotide consists of a sugar...

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Enzymes are biocatalysts. They catalyse biochemical reactions. In general,they reduce the activation energy of reactions. Many Physico chemical processes are enzyme-mediated. Which of the following reactions is not enzyme mediated in the biological system?

a. Dissolving CO2 in water b. Untwining the two strands of DNA c. Hydrolysis of sucrose d. Formation of peptide bond A)correct option -A B)Explanation of correct option - Carbon dioxide dissolves in...

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