Free Practice Questions for Biology in General-studies

SSC CGL 9-03-2020 (Morning)

IMPORTANT FACTS

• The flowers are the reproductive parts of a plant. 
• Stamens are the male reproductive part and pistil is the female reproductive part.

Stamen-

• Stamen consists of anther and filament.
• Filament is the slender thread-like structure that supports the anther.
• Anther makes the pollen grains and stores them. Pollen grains are exposed when the anther ripens and splits. 

Pistil-

• A pistil consists of stigma, style and ovary. 
• Stigma is the topmost part of the flower. It is often sticky in texture or contains tiny hair-like structures to help pollen adhere to its surface. 
• The style is the elongated part of a carpel that joins the ovary to the stigma. It is the tube through which pollen is delivered to the ovary.
• Ovary is the swollen part at the bottom of a pistil is called ovary. The ovary makes ovules and stores them. Ovules contain the female gametes (eggs) of the plant.

Stomata-

• Stomata are the structures which help in the exchange of gases. Opening and closing of the stomata are brought about by the guard cells present in them.
• They are present on the surface of the leaves.

The development of a fruit without fertilization is called parthenocarpy.

Important Points:

• True fruits are those that emerge solely from the ovary. 
• The thalamus has a role in fruit production in a few species, including apple, strawberry, and cashew. 
• Such fruits are known as fake fruits. 
• Fruits are the outcome of fertilisation in the majority of species; nevertheless, there are a few species where fruits develop without fertilisation. 
• These are known as parthenocarpic fruits. One such example is banana. 
• Parthenocarpy can be induced with growth hormones, and the resulting fruits are seedless.

SSC CPO 13/12/2019 (Morning)

Pollination-

• Pollination is the process of transfer of pollen grains from the anther of one flower to the stigma of the same or another flower.
• In self-pollination, pollen grains are transferred from the anther to the stigma of the same flower. It is also known as autogamy.
• In cross-pollination, pollen grains are transferred from the anther of one flower to the stigma of another flower of the same kind. It is also known as Xenogamy.
• Geitonogamy – Transfer of pollen grains from the anther to the stigma of another flower of the same plant.

SSC CPO 12/12/2019 (Evening)

IMPORTANT FACTS

• Thallophyte, Bryophyte, and Pteridophyte are called 'cryptogams'.
• Gymnosperms and angiosperms are called 'phanerogams'.
• Cryptogams are non–flowering and non-seed bearing plants.
• Phanerogams are flowering and seed-bearing plants.
• Gymnosperms  - They are non-flowering plants. They have naked seeds. Cycas, pinus, deodar, and Gingko are examples of gymnosperms. 
• Angiosperms – These are called flowering plants. Example – Wolffia, Eucalyptus. 
• Bryophytes are amphibians of the plant kingdom and occur in damp, humid places. Bryophytes lack true roots, stems, or leaves. 
• Thallophytes - The most primitive and simple plants that are not differentiated into roots, stems, and leaves are called thallophytes.  The plants in this group are commonly called algae. These plants are predominantly aquatic. 

SSC CPO 12/12/2019 (Morning)

IMPORTANT FACTS

Bisexual flower -

• The flower possessing both male and female reproductive parts is a bisexual flower that is both androecium and gynoecium are present in the same flower. Examples of bisexual flowers are rose, sunflower, hibiscus, lily, and mustard.

Complete flower -

• A flower that is built with four parts that include the sepals, petals, pistils, and stamens is called a complete flower. If any of these four parts, which are integral in forming a flower, is missing, a flower is called an incomplete flower.

Neuter flower-

• A flower in which both, male and female reproductive organs that are androecium and gynoecium are absent is called a neuter flower. E.g. Ray florets of a sunflower plant.

SSC MTS 08/08/2019 (Morning)

IMPORTANT FACTS

Fragmentation

• It is a form of asexual reproduction in which one organism breaks up into two to more fragments that further develop into new organisms.
• Example-An alga breaks up into two or more fragments. These fragments or pieces grow into new individuals. This process continues and they cover a large area in a short period of time.

Binary fission

• Binary fission is a method of asexual reproduction in which many single-celled organisms divide into two halves and each rapidly grows into an adult.
• It takes place in amoeba and bacteria.

Spore formation

• Spores are asexual reproductive bodies.
• Each spore is covered by a hard protective coat to withstand unfavourable conditions such as high temperature and low humidity. So they can survive for a long time.
• Under favourable conditions, a spore germinates and develops into a new individual. Plants such as moss, fungi and ferns reproduce by means of spores.

Gymnosperm are flowerless plants that produce cones and seeds in which seeds are not encased within an ovary.

Important Points:

• Gymnosperm plants have naked seeds and are often perennial, evergreen, and woody. 
• Gingko, pinus, and deodar are a few examples. 
• They do not produce flowers. 
• The root is usually a tap root that is connected with mycorrhiza. 
• The stem can be either branching (pinus) or unbranched (cycas). 
• Simple or complicated leaves are possible.

SSC-CHSL 3/07/2019 (Evening)

IMPORTANT FACTS

• Thallophyta, bryophyta and pteridophyta are called as 'cryptogams'.
• Gymnosperms and angiosperms are called as 'phanerogams'.
• Cryptogams are non – flowering and non- seed bearing plants.
• Phanaerogams are flowering and seed bearing plants.
• Angiosperms – These are called flowering plants. Example – Wolffia, Eucalyptus. 
• Bryophytes are amphibians of the plant kingdom, occur in damp, humid places. In bryophytes lack true roots, stem or leaves. 
• Pteridophytes are commonly called as reptiles of plant kingdom. Examples-Ferns, Horsetail. 
• Thallophytes - The most primitive and simple plants that are not differentiated into roots, stems and leaves are called thallophytes. The plants in this group are commonly called algae. These plants are predominantly aquatic. 

Fertilization takes place in the ovary part of the female flower.

Important Point:

• Stamens of a flower are the male reproductive organs and pistils are the female reproductive organs.
• The pistil contains the stigma, style and ovary.
• The ovary contains ovules and each ovule contains an ovum.
• The male gamete produced by the pollen grain fuses with the female gamete present in the ovule.
• This fertilization results in a zygote which is capable of developing into a new plant.
• The male reproductive cycle of a flower is called anther.
• The individual members of the anther are called stamens.
• Stamens contain anthers and filaments.

SSC-CGL 07/06/2019 (Morning)

IMPORTANT FACTS

Nitric oxide

• Chemical formula – NO
• It is also known as nitrogen monoxide.
• It is the main component of photochemical smog and occurs as a by- product of tobacco smoke, and gasoline engine exhaust. It is also used as bleaching agent for rayon and for making Nitric Acid and other Nitrogen compounds.

Carbon dioxide

• Chemical formula – CO₂
• Carbon dioxide is released into the atmosphere by respiration, burning of fossil fuels for energy, and by decomposition of limestone during the manufacture of cement. 
• It is also emitted during volcanic eruptions. Carbon dioxide gas is confined to troposphere only. 
• Deforestation and burning of fossil fuel increases the CO₂ level and disturb the balance in the atmosphere. The increased amount of CO₂ in the air is mainly responsible for global warming.
• It is a green house gas.

Nitrous oxide

• Chemical formula – N₂O
• It is also known as laughing gas.
• It is a greenhouse gas.

SSC CGL 17/08/21(Morning)

IMPORTANT FACTS

Pluripotency

• These cells do not exhibit full potency in the sense that they can get differentiated into most tissues of the body but are unable to produce all the tissues. Their differentiation potential is, thus, less than that of totipotent cells. This ability of the cell is referred to as pluripotency. 
• An example of pluripotent stem cells includes the cells derived from the inner cell mass. 

Cloning

• Cloning is the process of generating a genetically identical copy of a cell or an organism.
• A clone is a group of genetically identical cells. 

Mutation

• A mutation is a phenomenon that results in the alteration of DNA sequences and consequently results in changes in the genotype and the phenotype of an organism.
• A point mutation is a change of a single base pair in DNA.  Sickle-cell anemia is caused due to change of one base in the gene coding for the beta-chain of hemoglobin. 

SSC CGL 13/08/21 (Evening)

IMPORTANT FACTS

Veins :

• Veins are the vessels that carry carbon dioxide-rich blood from all parts of the body back to the heart. 
• The veins have thin walls. There are valves present in veins that allow blood to flow only toward the heart.
• Except for the pulmonary vein which carries oxygenated blood (oxygen-rich blood) from the lungs to the heart.

Arteries-

• Arteries carry oxygen-rich blood from the heart to all parts of the body. Except for pulmonary arteries which carry deoxygenated blood.
• Since the blood flow is rapid and at high pressure, the arteries have thick elastic walls.

Capillaries-

• On reaching an organ or tissue, the artery divides into smaller and smaller vessels to bring the blood in contact with all the individual cells. 
• The smallest vessels have walls that are one-cell thick and are called capillaries. 
• The exchange of material between the blood and surrounding cells takes place across this thin wall. 
• The capillaries then join together to form veins that convey the blood away from the organ or tissue.

The phenomenon whereby the female gamete undergoes development to form new organisms without fertilisation in some organisms like honey bees, some lizards and birds is calledparthenogenesis.

Options Explanation:

Apomixes- 

• It is the phenomenon that found in few flowering plants such as some species of Asteraceae and grasses that produce seeds without fertilization. 

Budding

• Organisms such as Hydra use regenerative cells for reproduction in the process of budding. In Hydra, a bud develops as an outgrowth due to repeated cell division at one specific site. 
• These buds develop into tiny individuals and when fully mature, detach from the parent body and become new independent individuals.

Fragmentation

• It is a form of asexual reproduction in which one organism breaks up into two to more fragments that further develop into new organisms.
• Example-An alga breaks up into two or more fragments. These fragments or pieces grow into new individuals. This process continues and they cover a large area in a short period of time.

Ovaries are the primary female sex organs, which produce female gametes.

Important Points:

• The female reproductive system consists of a pair of ovaries as well as the external genitalia located in the oviducts, uterus, cervix, vagina, and pelvic region.
• The fallopian tubes form the accessory vessels in the uterus and vagina.
• Ovary produces and releases egg. Female hormones (estrogen and progesterone) are produced in the ovaries.
• Fallopian tubes are the part of the human female reproductive system where the fusion of egg and sperm takes place.
• The shape of the uterus is like an inverted pear.
• In pregnancy, the fertilized egg implants in the uterus and an embryo develops into a child.

SSC CPO 13/12/2019 (Evening)

IMPORTANT FACTS

Male reproductive system

• The male reproductive system is located in the pelvis region. It includes a pair of testes along with accessory ducts, glands and the external genitalia.
• The male sex accessory ducts include rete testis, vasa efferentia, epididymis and vas deferens. 
• The male accessory glands include paired seminal vesicles, a prostate and paired bulbourethral glands.
• The testes are situated outside the abdominal cavity within a pouch called scrotum. The testes are the primary reproductive organs. The scrotum helps in maintaining the low temperature of the testes (2–2.5^oC lower than the normal internal body temperature) necessary for spermatogenesis.

Female reproductive system

• The female reproductive system consists of a pair of ovaries along with a pair of oviducts, uterus, cervix, vagina and the external genitalia located in pelvic region. 
• Ovaries are the primary female sex organs that produce the female gamete (ovum) and ovarian hormones (estrogens and progesterone). 
• The oviducts (fallopian tubes), uterus and vagina constitute the female accessory ducts.
• The shape of the uterus (womb) is like an inverted pear. If pregnancy occurs, the fertilized egg will implant in the uterus and grow into a foetus and then a baby here. The uterus opens into the vagina through the cervix.
• Vagina is a muscular tube connecting the cervix to the outside of the body. It also serves as the canal for receiving the semen at the time of copulation.

SSC MTS 14/08/2019 (Afternoon)

IMPORTANT FACTS

External fertilization -

• In most aquatic organisms, such as a majority of algae and fishes as well as amphibians, syngamy occurs in the external medium (water), i.e., outside the body of the organism. This type of gametic fusion is called external fertilisation.

In vitro fertilisation (IVF)–

• This fertilisation takes place outside the body in almost similar conditions as that in the body. In this method, ova from the wife/donor (female) and sperms from the husband/donor (male) are collected and are induced to form zygote under simulated conditions in the laboratory. The zygote or early embryos (with upto 8 blastomeres) could then be transferred into the fallopian tube (ZIFT–zygote intra fallopian transfer) and embryos with more than 8 blastomeres, into the uterus (IUT – intra uterine transfer), to complete its further development. Babies born through this technique are called test-tube babies.

In vivo fertilization - 

• In this type of fertilization, the fusion of sperm with egg occurs within the body of a female. Transfer of an ovum collected from a donor into the fallopian tube (GIFT – gamete intra fallopian transfer) of another female who cannot produce one, but can provide suitable environment for fertilisation . The semen collected either from the husband or a healthy donor is artificially introduced either into the vagina or into the uterus (IUI – intra-uterine insemination) of the female.

Fertilizations  takes place in the fallopian tube in human .

Important Points:

• The fusion of the nuclei of sperm and ovum is called Fertilizations. 
• It results in the formation of single-celled Zygote cells, which develop into embryos. 
• The embryo receives nutrition from the mothers' blood through placenta.
• The villi provide a large surface area for glucose and oxygen to pass from the mother to the developing embryo, as well as wastes to pass from the embryo to the mother via the placenta. 

SSC-CGL 11/06/2019 (Morning)

IMPORTANT FACTS

Animals are categorised into oviparous and viviparous based on whether the development of the zygote takes place outside the body of the female parent or inside, i.e., whether they lay fertilised/unfertilised eggs or give birth to young ones. 

SSC-CGL 10/06/2019 (Evening)

IMPORTANT FACTS

• Egg – first stage in life cycle from which larva hatches.
• Larva – juvenile phase with different physical appearance from adult.
• Caterpillar – larva phase for butterflies.
• Pupa – intermediate phase between larva and adult.
• Chrysalis – essentially pupa stage of development within which the caterpillar undergoes the transformation to become a butterfly.
• Cocoon – protected chamber for pupa while body undergoes transformation.
• Adult – mature phase of insect (phase that is able to reproduce).

Ringworm is a contagious fungal infection of the skin.

Important Points:

• The infected area of skin is an itchy, red, raised, scaly patch (with sharply defined edges).
• It is more red on the periphery than in the center, which resembles a ring.
• Several fungi belonging to the genera Microsporum, Trichophyton, and Epidermophyton are responsible for ringworm.
• These fungi feed on the keratin in the skin, hair and nails.
• Ringworm is usually acquired from soil or by using towels, clothing or combs of infected persons.
• These diseases are caused by pathogens such as bacteria, fungi, protozoa, etc. These diseases are also called communicable diseases.