Biology — Part 1 MCQs with Explanations

Sodium bicarbonate is baking soda.

The term 'ozone hole' refers to the depletion of the protective ozone layer in the upper atmosphere (stratosphere) over Earth's polar regions. Stratospheric ozone is constantly produced by the action of the sun's ultraviolet radiation on oxygen molecules (known as photochemical reactions).

Pine, fir, spruce, cedar, larch and cypress are the famous timber-yielding plants of which several also occur widely in the hilly regions of India. All these belong to gymnosperms, a taxonomic class that includes plants whose seeds are not enclosed in an ovule.

Pollination can be best defined as the transfer of pollen from the male anther of a flower to the female stigma to produce new offspring.

Plants receive their nutrients mainly from soil.

Active transport, this is the only transport method that can move species against their concentration gradient (from low to high concentration). Facilitated diffusion only moves species down their concentration gradient from high to low concentration.

In plants, the process of photosynthesis takes place in the mesophyll of the leaves, inside the chloroplasts. Chloroplasts contain disc-shaped structures called thylakoids, which contain the pigment chlorophyll.

Fishes have a swim bladder or air bladder which helps them to remain buoyant without sinking in water. They are present in the body cavity.

We know that, proteins are polymers of amino acids. So, plants are also used to synthesise protein from amino acids. Hence, plants synthesis protein from amino acids in the presence of ATP by specific synthetases.

The plant cells absorb nitrates from the soil and convert them into ammonia which ultimately reduced to ammonium ions (NH4+). These ammonium ions are then combined with organic compounds to form amino acids such as glutamine i.e., free nitrogen. This process of conversion is known as nitrogen fixation.

Out of 900 reported species of living gymnosperms, conifers are represented by about 500 species, About 2,50,000 species of angiosperms (flowering plants) have also been reported in the world. The vast and dominant woodlands in Europe, Asia, North America and mountains such as Himalayas are wooded with only conifers.

Secretion of hormones for calcium regulation in blood and bones is not a function of a bone.

Root hair cells are specialized epidermal cells that greatly increase the surface area of roots. The function of root hairs is to collect water and mineral nutrients present in the soil and take this solution up through the roots to the rest of the plant.

Mitosis is a process of nuclear division in eukaryotic cells that occurs when a parent cell divides to produce two identical daughter cells. During cell division, mitosis refers specifically to the separation of the duplicated genetic material carried in the nucleus.

Dolphins are the most highly intelligent mammals.

Plant development is influenced by quality, quantity and duration of light. Plants cannot get too much light, but they can get too much of the heat energy that comes with the light.

Prokaryotic cells lack nucleolus, nuclear membrane and membrane bound by organelles.

Photosynthesis takes place faster in red light . Photosynthesis is the process by which green plants and some other organisms convert light energy into chemical energy. It primarily occurs in chloroplasts, where pigments such as chlorophyll absorb light. While chlorophyll absorbs light from various parts of the light spectrum, it is most efficient in the red and blue parts of the spectrum. Red light is absorbed more effectively than other colors, making it the most favorable for photosynthesis. So, the correct option is: Option C: red light Photosynthesis takes place faster in red light .

Nucleus, the genetic material containing rounded body in each cell, was first discovered in 1831 by Robert Brown.

Primary phloem develops from provascular tissue.

Other than spreading malaria, anopheles mosquitoes are also vectors of filariasis.

A halophyte is a salt-tolerant plant that grows in soil or waters of high salinity, coming into contact with saline water through its roots or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs and seashores.

Pyorrhoea, or periodontal disease, to give it a proper medical term, is a disease of the gums, it is one of the most widely prevalent diseases. It affects the membrane surrounding the roots of the teeth and leads to loosening of the teeth, pus formation, and shrinkage of the gum. This disease is the primary cause for tooth loss among adults.

Photosynthesis is the process by which plants use the energy of light to produce carbohydrates and molecular oxygen (O 2 ) from carbon dioxide (CO 2 ) and water.

Placenta is the structure formed by the union of foetal and uterine tissue.

Plants hormone that induces cell division is cytokinins.

Neurospora is used as genetic material because it has short life cycle of 10 days.

Phloem, also called bast, tissues in plants that conduct foods made in the leaves to all other parts of the plant. Phloem is composed of various specialized cells called sieve tubes, companion cells, phloem fibres, and phloem parenchyma cells.

N 2 content is kept constant in the biosphere due to nitrogen cycle.

Carbohydrates are minimum in a cell membrane.

Potato is a modified form (outgrowth) of stem.

Of the following taxonomic categories class is the most inclusive (i.e. is the highest in hierarchy).

Prothrombin is a plasma protein which is converted into thrombin in the presence of thromboplastin released by platelets at the site of injury. The thrombin then converts protein fibrinogen into insoluble fibrin and thus aids in blood clotting.

Myopia is connected with eyes.

Anthocyanin - A blue, violet, or red flavonoid pigment found in plants.

Xerophytes are adapted to survive in hot deserts where there is very little water. Xerophytes are common in coastal areas and thrive in saline water.

Psammophytes are plants that preferentially grow in sand.

Within the skin's epidermal (outer) layer are cells that contain the pigment melanin. Suntanning occurs because exposure to sunlight causes the skin to produce more melanin and to darken. The tan fades as these cells move toward the surface and are sloughed off.

Ramapithecus and Cro-Magnon man are considered ancestors of modern man.

Normal adult human male has 14 gram of haemoglobin/100 gram of blood.