#neet
- Which of the following would appear as the pioneer organisms on bare rocks ? Answer: 1. Lichens On bare rock, lichens are the pioneer species of primary succession. They secrete acids, weather the rock and form soil,... 1
- Which one of the following characteristics is not shared by birds and mammals ? Answer: 3. Viviparity Both birds and mammals have a bony endoskeleton, breathe with lungs and are warm blooded. Viviparity (giving birth to... 1
- Nomenclature is governed by certain universal rules. Which one of the following is contrary to the rules of nomenclature ? Answer: 1. Biological names can be written in any language Biological names must be in Latin (or Latinised) form, whatever the language of t... 1
- Blood pressure in the pulmonary artery is : Answer: 3. more than that in the pulmonary vein. The pulmonary artery carries blood from the right ventricle at a pressure much higher than... 1
- Which is the National Aquatic Animal of India ? Answer: 2. River dolphin Key idea: The river dolphin (Gangetic dolphin, Platanista gangetica) is India's National Aquatic Animal, declared i... 1
- One of the major components of cell wall of most fungi is : Answer: 1. Chitin Key idea: The fungal cell wall is made mostly of chitin (a polymer of N-acetylglucosamine) and polysaccharides. Peptidogly... 1
- In meiosis crossing over is initiated at : Answer: 1. Pachytene Key idea: Crossing over takes place at pachytene. At pachytene (prophase I), recombination nodules form and the enzyme... 1
- The taq polymerase enzyme is obtained from : Answer: 1. *Thermus aquaticus* Key idea: Taq polymerase comes from the thermophilic bacterium Thermus aquaticus. It is stable at the high te... 1
- Photosensitive compound in human eye is made up of : Answer: 2. Opsin and Retinal Key idea: The photosensitive pigment of the eye, rhodopsin (visual purple), is made of opsin (a protein) and re... 1
- Spindle fibres attach on to : Answer: 2. Kinetochore of the chromosome Key idea: Spindle fibres attach to the kinetochore. The kinetochore is a disc-shaped protein struct... 1
- Which of the following is required as inducer(s) for the expression of Lac operon ? Answer: 3. lactose Key idea: In the lac operon, lactose (as allolactose) is the inducer. It binds the repressor protein, which then leaves t... 1
- Which of the following pairs of hormones are not antagonistic (having opposite effects) to each other ? Answer: 4. Relaxin - Inhibin Key idea: Antagonistic hormones have opposite effects. Parathormone raises blood calcium; calcitonin lowers it.... 1
- Microtubules are the constituents of : Answer: 2. Spindle fibres, Centrioles and Cilia Key idea: Microtubules make up spindle fibres, centrioles (and basal bodies), and the axonem... 1
- A complex of ribosomes attached to a single strand of RNA is known as : Answer: 1. Polysome Key idea: Several ribosomes attached to one mRNA strand make a polysome (polyribosome), so many copies of a polypeptide... 1
- Fertilization in humans is practically feasible only if : Answer: 2. the ovum and sperms are transported simultaneously to ampullary - isthmic junction of the fallopian tube. Key idea: Fertilization... 1
- Asthma may be attributed to : Answer: 2. allergic reaction of the mast cells in the lungs Key idea: Asthma is an allergic reaction that inflames the bronchi and bronchiol... 1
- The *Avena* curvature is used for bioassay of : Answer: 3. IAA Key idea: The Avena (oat coleoptile) curvature test is a bioassay for the auxin IAA. Auxin placed on one side of a decapitate... 1
- The standard petal of a papilionaceous corolla is also called : Answer: 3. Vexillum Key idea: In a papilionaceous corolla (pea family), the large back petal is the standard or vexillum. There are two late... 1
- Tricarpellary, syncarpous gynoecium is found in flowers of : Answer: 1. Liliaceae Key idea: Liliaceae flowers have a tricarpellary, syncarpous gynoecium (superior ovary). Solanaceae has a bicarpellary... 1
- Select the incorrect statement : Answer: 3. LH and FSH decrease gradually during the follicular phase. Key idea: LH and FSH rise, not fall, during the follicular phase. FSH... 1
- A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F_1 plants were selfed the resulting genotypes were in the ratio of : Answer: 1. 1 : 2 : 1 :: Tall homozygous : Tall heterozygous : Dwarf Key idea: A TT × tt cross gives all Tt in F₁. Selfing F₁ (Tt × Tt) gives... 1
- Which of the following is the most important cause of animals and plants being driven to extinction ? Answer: 3. Habitat loss and fragmentation Key idea: The most important cause of species extinction is habitat loss and fragmentation. Over-e... 1
- Which one of the following is a characteristic feature of cropland ecosystem ? Answer: 2. Least genetic diversity Key idea: A cropland is a managed ecosystem where people grow one or a few crop species. This gives the l... 1
- Changes in GnRH pulse frequency in females is controlled by circulating levels of : Answer: 1. estrogen and progesterone Key idea: GnRH pulse frequency in females is controlled by the circulating levels of oestrogen and prog... 1