CUET ug Biology Mock Test 2 (Free Available)

Right Answer Is B
Monerans (Bacteria) and protists both exhibit binary fission which is a type of asexual reproduction. In binary fission, a parent cell simply divides by mitosis to give rise to two new individuals. Vegetative propagation is the method of reproduction used to produce new plants by using a vegetative part of the parent plant.
Apomixis is the formation of a plant from a seed that does not require fertilisation or normal sexual reproduction. Amphimixis is a form of sexual reproduction where the ovum and spermatozoa of the male and female parents fuse during fertilisation, resulting in the formation of zygotes. Both apomixis and amphimixis occur in plants.

Right Answer Is A
Uniparental reproduction in animals and simple organisms is called asexual reproduction whereas in plants it is known as vegetative reproduction. In sexual reproduction, two different gametes produced by opposite sexes of the same species are fused together. Thus, two members are involved in sexual reproduction. But in asexual and vegetative (in plants) reproduction, new individuals are produced from a single parent, thus, it is uniparental.

Right Answer Is C
Vegetative reproduction is any type of asexual reproduction that occurs in plants and results in the formation of a new plant from a fragment, part or cutting of the parent plant or specialised reproductive structures known as vegetative propagules.
Examples of vegetative propagules are rhizome, sucker, offset, stolon, bulb, tuber, leaf bud, etc. However, antherozoid is the male gamete of the bryophyte produced in its male gametophyte i.e. antheridium.

Right Answer Is D
Pollen grains are the male gametophytes of angiosperm plants. They consist of one tube/vegetative cell and one generative cell. Pollen germinates on the stigma of the female sex organ to produce a tube from vegetative cells whereas the generative cell divides to produce two male gametes.

Right Answer Is D
Microsporangium is a cell mass which develops inside a pollen sac of an anther (male part of the flower). The pollen mother cells of microsporangium divide to form microspores which then develop to form pollen grains. However, the embryo sac is the female gametophyte of angiosperms which is developed from the megaspore cell.

Right Answer Is B
Microsporangium is made up of pollen mother cells or microspore mother cells. These cells are produced by the sporogenous tissue which is a cell mass of homogenous cells present in the centre of the microsporangium. However, tapetum and endothecium are the layers which envelop microsporangium.

Right Answer Is D
Pollen mother cells or microspore mother cells are present inside the microsporangium which divides to form microspores which then develop to form pollen grains. This process of formation of pollen grains is referred to as microsporogenesis. Thus, pollen mother cells or microspore mother cells perform microsporogenesis.

Right Answer Is C
The scrotum is a pouch of skin that holds and protects the testicles. The testicles produce sperm, and in order to do so, the temperature of the testicles must be lower than the temperature of the rest of the body.
This explains why the scrotum is external to the body. Hence, the scrotum helps to maintain a temperature lower than the abdomen temperature.

Right Answer Is D
Cryptorchidism or undescended testes is a situation in which one or both testes do not move into the scrotum at birth, but instead remain in the abdomen or move only partially into the scrotum. If a testis remains in the abdomen at puberty, no sperm can produce in that testis, which could lead to low sperm count as well as infertility.
Impotence is the incapability to obtain and maintain a firm enough erection for sex. Paedogenesis refers to sexually mature larvae reproducing without fertilisation. Castration refers to any action that causes a person to lose the use of his testicles.

Right Answer Is C
The fibrous tissue surrounding the testis is known as the tunica albuginea. It is a tightly packed blue-grey membrane made up of white fibrous connective tissue bundles. The tunica vaginalis covers it except at the points where the epididymis attaches to the testis as well as along its posterior border, where the spermatic vessels join the gland.

Right Answer Is D
The World Health Organization (WHO) defines reproductive health as total well-being in every aspect of reproduction, including physical, social, emotional, and behavioural well-being.

Right Answer Is D
Amniocentesis is the removal of amniotic fluid by inserting a needle into the amniotic sac. The amniotic liquid contains amniotic membrane cells, which are used to detect chromosomal abnormalities such as Down’s syndrome and haemophilia in the foetus, as well as to determine the sex of the foetus.
Cleft palate, on the other hand, is caused by both environmental and genetic factors and cannot be identified using amniocentesis.

Right Answer Is D
Contraception is defined as the deliberate prevention of reproduction with the help of various devices, sexual practices, chemicals, drugs, and other methods. An ideal contraceptive should be simple to use, easily accessible, effective, and reversible, with no or few side effects.

Right Answer Is A
Mendel chose 14 true-breeding plants (pure-line plants) in seven pairs, which means that 7 plants have dominant traits and the other 7 have recessive ones. :

Right Answer Is A
The phenotype of F1 progeny if a pure tall plant is crossed with a pure dwarf plant will be tall. When a pure tall (TT) plant will be crossed with a pure dwarf (tt) plant, all the F1 progenies obtained will be heterozygous tall (Tt).

Right Answer Is C
The heterozygous tall plant is represented by Tt. When one Tt is crossed with another Tt, the F1 progenies obtained will be TT (homozygous tall) = 1 Tt (heterozygous tall) = 2 tt (homozygous dwarf) = 1 Thus, tall by dwarf ratio will be 3: 1.

Right Answer Is A
Mendel did self-pollination of F1 progenies to obtain recessive trait in the F2 generation. Firstly, a pure tall plant (TT) was crossed with a pure dwarf plant (tt). The progenies obtained in the F1 generation were all heterozygous tall (Tt).
These progenies were self-pollinated to obtain the recessive trait (dwarfism) in the progenies of the F2 generation. The ratio of tall to dwarf progenies in the F2 generation was 3: 1.

Right Answer Is D
The DNA molecule is made up of two strands which swirl around each other like a helical structure. Each DNA strand has an alternating backbone of sugar and phosphate groups.

Right Answer Is A
In normal conditions, genetic information transmits from DNA to RNA and then to protein. This flow of genetic information is also referred to as the central dogma of life. The process of decoding a DNA segment into RNA is known as transcription.
When the same process occurs in the opposite direction i.e. from RNA to DNA, it is termed reverse transcription. This process occurs only in some viruses which have reverse transcriptase enzymes.

Right Answer Is B
Histones are the positively charged basic (alkaline) proteins which help to concentrate negatively charged DNA to form chromosomes. Lysine and arginine are amino acids, not proteins. Protamines are the proteins which convert the active genome of spermatids into their inactive form.

Right Answer Is B
The bones of the forelimbs of whales, bats, cheetahs, and humans are structurally similar because these are homologous organs. Homologous organs are organs that share the same fundamental structure but perform different functions.
During their development, these organs adhere to the same basic plan of organisation. Divergent evolution creates these structures. Homology i.e. similar structures denote a common ancestor of the homologous organisms.

Right Answer Is A
Analogous organs are organs that perform similar functions but differ in anatomical structure. For example, insect and bird wings. Both insects and birds use their wings to fly, but their anatomical structure and origin are distinct.
Convergent evolution is referred to as the process by which distantly related organisms evolve similar traits independently in order to adapt to similar needs. Thus, convergent evolution gives rise to analogous organs.

Right Answer Is A
The Hardy-Weinberg equation is a mathematical expression or formula that can be used to measure a population’s genetic variation at equilibrium. It is written as, p2 + 2pq + q2 =1, where p is the dominant allele’s frequency and q is the recessive allele’s frequency in a population. Thus, it is used in population genetics.

Right Answer Is C
Pneumonia is an infection that leads to inflammation of air sacs in the lungs. The air sacs may become clogged with fluid or pus, resulting in phlegm or pus cough, chills, fever, and breathing difficulty. Various organisms can cause pneumonia and these organisms include bacteria, viruses, and fungi. Streptococcus pneumoniae is the main organism that causes bacterial pneumonia.

Right Answer Is B
Diphtheria mostly affects children under the age of five. A sore throat, vomiting, headache, chills with a low body temperature, etc are the symptoms of this disease. Hoarseness and difficulty in breathing can result from the formation of a grey membrane in the throat or tonsils.

Right Answer Is B
The DPT vaccine is a three-in-one or combination vaccine that protects children from tetanus, whooping cough, and diphtheria. In DPT, ‘D’ represents diphtheria, ‘P’ represents pertussis (whooping cough), and ‘T’ represents tetanus. The DPT vaccine should be given to the baby within 6 weeks of birth.

Right Answer Is D
Apiculture refers to the domestication of honeybees to obtain honey and wax. However, the process of harvesting silkworms, fish and chickens is known as sericulture, pisciculture and poultry farming respectively.

Right Answer Is C
Honey bees use the tail-wagging dance to share information about the location of a fine source of water, food, or nectar-rich flowers. When foraging worker honey bees leave the nest or hive, they seek flowers to gather nectar. When they find a suitable source of nectar, all bees gather and perform a waggle dance to inform the rest of the colony about the new food location.

Right Answer Is A
Silkworms eat mulberry leaves and produce pupa. To keep itself together during the pupa stage, the silkworm weaves a net around itself. Then it rotates its head to spin a protein fibre around it that eventually becomes silk. Thus, in the pupal stage, silk can be obtained from the silkworm.

Right Answer Is C
Clostridium butyricum is used to produce butyric acid at the commercial level. However, Streptomyces, Lactobacillus and Acetobacter aceti are used for the commercial production of antibiotics, curd and acetic acid respectively.

Right Answer Is C
Trichoderma polysporum is a fungus which produces cyclosporin-A. Cyclosporin is an immunosuppressive medication used to treat organ rejection following transplantation. However, most of the statins are produced by Aspergillus fungus and streptokinase by Streptococcus bacteria.

Right Answer Is D
Viroids are infectious agents made up entirely of a single circular single-stranded RNA with some double-stranded regions. The bacterium is a unicellular prokaryotic cell made up of a cell wall, cell membrane and cytoplasm.
Fungus is a eukaryotic organism which can be unicellular or multicellular. Viruses are non-living entities which have genetic material enclosed in a protein coat.

Right Answer Is A
The Human Genome Project was founded in 1990 by the US Department of Energy and the National Institute of Health (NIH). The 13-year megaproject intended to sequence the entire 3 billion DNA base pairs that comprise the human genome.

Right Answer Is C
Third-generation vaccines are actually plasmids that are directly injected into the body and are capable to express the required gene within the cells. The recombinant protein is created in the body and deposited in the immune system after the plasmid is inserted into the body.

Right Answer Is D
A scientist named Karry Mullis discovered the technique of amplifying DNA segments to produce a million copies in a very small time and this technique is called polymerase chain reaction (PCR ). He also earned the Nobel Prize in Chemistry for this invention.

Right Answer Is C
Bacillus thuringiensis produces a large group of crystalline toxins known as cry proteins. Bacillus thuringiensis is a genus of Gram-positive aerobic bacteria that form large crystalline inclusions-containing insecticidal protein toxins. Cry toxins are a significant component of these inclusions.

Right Answer Is D
Bacillus thuringiensis is a bacterium that contains the cry toxin and is widely used as a biopesticide. Scientists have inserted cry toxin-producing genes (Cry genes) into normal plants and raised genetically engineered insect-resistant plants. For example, Bt-cotton. Cry genes were introduced in many plants like cotton, corn, potato, tomato, rice, etc to create their genetically modified versions.

Right Answer Is D
Bacillus thuringiensis is a bacterium which produces Bt-toxin. This toxin kills insects of orders like lepidopterans, coleopterans, and dipterans by anchoring and creating pores in the epithelium cell surface of their midgut.

Right Answer Is C
The tallest trees are emergents, which can reach up to 200 feet higher than the forest floor and have trunks up to 16 feet in diameter. The majority of these trees are hardwood evergreens with broad leaves. Due to this feature of tall plants, both the quality and intensity of light reaching the forest floor is very poor. Thus, tall trees control the intensity of sunlight on the ground of forests.

Right Answer Is B
An ecotone is a zone of transition or boundary between two biological communities where the two communities meet and merge. It can be narrow or wide, as well as local or regional.

Right Answer Is D
The tiger census is conducted in India every year. This is executed to figure out how many tigers there are in our country. The tiger count is based on their pug marks and faecal pellets. This allows us to count them and determine their species.

Right Answer Is B
Fungi are heterotrophic lifeforms that do not produce food for themselves. They depend on other organisms for their nutrition. Some fungi consume the dead fragments of plants and animals for nutrients, causing organic waste to decompose. As a result, they are known as natural scavengers.

Right Answer Is A
Trees are enormous, but herbivores such as caterpillars are tiny. One tree can feed many caterpillars, but it takes many caterpillars to feed one sparrow, and many tiny sparrows to feed a sparrow hawk. The number pyramid for this food chain will be spindle-shaped.
On the other hand, there is a single primary consumer or tree but primary consumers are numerous, and parasites are the most numerous. For this tree ecosystem, the number pyramid will be inverted. Thus, a tree ecosystem pyramid of numbers can be both spindle-shaped and inverted.

Right Answer Is D
Humus is a colloidal substance that is amorphous, dark in colour, and acidic in nature. It is extremely resistant to microbial action. It is found in soils and peat bogs. It improves soil quality by supplying nutrient substances.

Right Answer Is B
Insects comprise the most species-rich taxonomic group among animals, accounting for more than 70% of the total. That means that seven out of every ten animals on the planet are insects.

Right Answer Is B
In-situ conservation refers to the act of preserving the endangered plant or animal species in their natural habitat. For example, in National parks, Sacred groves, Sanctuaries, etc. Ex situ conservation, on the other hand, refers to the shifting of an endangered or rare species from its natural habitat to protected areas designed for its protection and preservation. For example, cryopreservation of seeds of endangered plant species.

Right Answer Is D
Fungi are found all over the world and grow in a variety of environments, including deserts, high-salinity areas as well as deep-sea sediments. They have the maximum number of species in terms of global biodiversity.

Right Answer Is B
Ozone depletion accelerates the harmful solar UV radiation reaching the Earth’s surface, which has a number of negative consequences, such as an increase in the rate of skin cancer. It is because UV radiation is one of the physical mutagens.

Right Answer Is A
CNG or compressed natural gas is widely used as a fuel in automobiles. This gas has a major component which is methane gas (~80%).

Right Answer Is B
Particles with a diameter of 2.5 micrometres can travel deep into the respiratory tract and reach the lungs. Their exposure can result in short-term health impacts like irritation of the eyes, nose, throat, and lungs, coughing, sneezing, and shortness of breath.