List of top Biology Questions

Refer to the transverse section of ovary of mustard plant. Identify $X$ and $Y$ in it.
Regulation of gene expression occurs at the level of
Refer to the given table of contrasting traits in pea plants studied by Mendel. Which of the given traits is correctly placed ?
Refer to the given statements' and select the correct ones (i) Fossils are remains of hard parts of life forms in rocks (ii) Dinosaurs disappeared about $65$ mya (iii) Animals called lobe fins evolved into reptiles (iv) Study of fossils is called palaentology
Refer to the given stages $A, B, C$ and $D$ of meiosis $I$ and select the incorrect statement regarding them.
Refer to the given figures showing structure of dicotyledonous seed and select the option that correctly identifies any of the labelled parts.
Refer to the given figure showing reproductive system of female cockroach
Identify the parts labelled as $P, Q, R$ and $S$ and select the correct statement regarding these
Refer the given figure of nudeosome and select the option that correctly identifies the parts $A, B$ and $C$.
Refer to the given figure of reproductive structure of Papaverand identify $X$ and $Y$.
Red data book was first brought out in
Red colour of tomatoes, carrots and chillies is due to the presence of a type of carotene pigment called as
Red Data Book deals with
Rearrange the following zones as seen in the root in vertical section and choose the correct option. A. Root hair zone B. Zone of meristems C. Root cap zone D. Zone of maturation E. Zone of elongation
Read the given statements that refer to different stages of plasmolysis. Select the correct option regarding them. (i) First stage of plasmolysis, when osmotic concentration of cell sap is just equivalent to that of external solution. (ii) Protoplast withdraws itself from corners of the cell wall. (iii) Protoplast gets detached from the cell wall and attains a spherical shape.
Read the given statements that describe certain infectious particle. (i) It was discovered by $T.O$. Diener and was found to be smaller than viruses. (ii) It causes potato spindle tuber disease. (iii) It is a free $RNA$ particle which lacks the protein coat. (iv) It has low molecular weight $RNA$ as genetic material. Which of the following is referred to here?
Read the given statements and select the correct option. Herbivores are also called as first order consumers. Herbivores obtain their food directly from plants.
Read the given statements and select the correct option. Amphibians often hibernate in winter and aestivate in summer. They are poikilothermic animals and cannot regulate body temperature.
Read the given statements and select the correct option. Carboxylation is the most crucial step of Calvin cycle where $CO_{2}$ is utilised for the carboxylation of $RuBP$. Carboxylation is catalysed by the enzyme $RuBisCO$ which results in the formation of two molecules of $3PGA$.
Read the given statements and select the correct ones. (i) A membrane which permits the passage of pure solvent molecules to pass through it and not the solute particles is called semi-permeable. (ii) A membrane which allows some substances to pass through it more readily than others is known as selectively/ differentially permeable. (iii) All living biological membranes are perfectly semipermeable.
Read the given statements and select the correct option (i) Synaptic cleft of neurons secretes adrenaline (ii) Myelinated nerve fibres are enveloped with Schwann cells, which form a myelin sheath around the axon (iii) Non-myelinated nerve fibre is enclosed by a Schwann cell that does not form a myelin sheath (iv) Spinal and cranial nerves are made of non myelinated nerve fibres
Read the following statements regarding euglenoids and select the incorrect ones. (i) These are mostly freshwater organisms found in stagnant water. (ii) Their body is covered by a protein rich layer called pellicle which makes their body flexible. (iii) They are photosynthetic in the presence of sunlight but become heterotrophs in the absence of sunlight. (iv) They usually possess two flagella, one long and one short. (v) Euglenoids are multicellular ciliate protists.
Read the following statements (P - T) and select the option that correctly fills (i) - (v). P. The male frog has a special organ on the throat called membrane is a part of ear and serves to receive sound waves R. Dermis of the frog contains sac-like glands S. Tongue of frog is T. respiration takes place in lungs on land
Read the following statements and select the incorrect ones. (i) Homeostasis, ensures constant osmotic concentration of cells. (ii) The famous Keoladeo National Park (Bharatpur) in Rajasthan hosts thousands of migratory birds coming from Siberia, in every winter. (iii) $99\%$ of animals and nearly all plants are regulators. (iv) The conformers are able to maintain their body temperature inspite of changes in ambient temperature.
Read the following statements and select the option which identifies the incorrect ones. (i) Potato spindle tuber disease and Chrysanthemum stunt disease are caused by viroids. (ii) $T_{4}$ bacteriophage exhibits lytic cycle. (iii) Retroviruses have two copies of $ssRNA$. (iv) Interferons which prevent viral multiplication are glycolipid particles.
Read the following statements and select the correct option. Besides curdling of milk, $LAB$ also improve its nutritional quality by increasing vitamin $B_{12}$. $LAB$, when present in human stomach, check disease causing microbes.