Biology: CUET Mock Test - 5 - CUET MCQ

Brassica crops are the most suitable location for keeping beehives. This is because Brassica plants, such as mustard, produce large amounts of nectar, which bees can use to make honey. The presence of beehives near Brassica crops not only aids in the production of honey but also enhances the pollination of these crops, leading to better yields.

Key Points

• Brassica crops such as mustard are highly beneficial for beekeeping due to their high nectar production.
• The placement of beehives near these crops can significantly improve their pollination and, subsequently, crop yield.

Additional Information

• Potato and Ginger crops are less suitable for beekeeping as they do not produce as much nectar as Brassica crops.
• While Sugarcane can produce a significant amount of nectar, its tall structure can make it difficult for bees to access compared to the open flowers of Brassica.
• Choosing the right location for beehives is crucial for both the health of the bees and the productivity of the crop.

The correct match will be:

Mendel’s Law of Independent Assortment states that genes for different traits are inherited independently of each other.

The numbers 9, 3, 3, and 1 represent the different combinations of dominant and recessive traits seen in the offspring.

The Law of Independent Assortment is illustrated by the dihybrid cross, where two traits assort independently.

The F2 generation of a dihybrid cross follows a phenotypic ratio of 9:3:3:1, showing the different combinations of two traits.

(A) Correct: Mutation and genetic recombination are essential sources of genetic variation in populations.
(B) Incorrect: Darwin’s theory was not fully accepted immediately, as it lacked knowledge about genetics at the time.
(C) Correct: The fossil record provides important evidence of the gradual changes in life forms over geological time.
(D) Correct: Speciation leads to the formation of new species when populations become reproductively isolated and evolve differently.
(E) Incorrect: Natural selection operates on both phenotypic and genotypic traits because phenotypes are determined by genotypes.

(A) Correct: Immunity can be acquired through vaccination, which helps build memory against specific pathogens.
(B) Incorrect: Passive immunity is immediate and temporary, as it involves the direct transfer of antibodies.
(C) Correct: The body produces antibodies in response to antigens to neutralize pathogens.
(D) Correct: Malaria is transmitted by the bite of an infected Anopheles mosquito.
(E) Incorrect: HIV is transmitted through blood, sexual contact, or from mother to child, not through casual contact.

(A) Correct: Lactic acid bacteria (LAB) are used to ferment milk into curd.
(B) Correct: Saccharomyces cerevisiae is used in fermentation processes to produce ethanol and alcoholic beverages.
(C) Incorrect: Penicillin is produced by the fungus Penicillium notatum, not a bacterium.
(D) Incorrect: Microbes like bacteria and fungi are essential in the production of many food items, including cheese.
(E) Correct: Methanogens are responsible for producing biogas from plant waste.

Watson and Crick proposed the double-helix model of DNA structure in 1953, based on data from X-ray diffraction by Franklin and Wilkins.

The two strands of DNA are complementary, meaning that adenine pairs with thymine, and guanine pairs with cytosine, maintaining the stability of the helix.

The stability of the DNA structure is due to hydrogen bonds between complementary bases, such as adenine and thymine, and guanine and cytosine.

DNA replication ensures that each daughter cell receives an identical copy of the DNA, maintaining genetic continuity.

Complementary base pairing ensures that the correct base is added during DNA replication, maintaining the accuracy of the genetic code.

(A) Correct: Trichoderma is a fungus used as a biocontrol agent to fight against plant pathogens.
(B) Correct: Biogas is produced by methanogens from organic waste, including animal dung.
(C) Correct: Fermentation for industrial purposes occurs in large vessels known as fermentors.
(D) Incorrect: Antibiotics are produced by both bacteria and fungi, not just fungi.
(E) Incorrect: Biofertilizers are living organisms, not chemical substances.

Signal for parturition comes from fully developed fetus and placenta. Oxytocin and relaxis play major role in parturition fetus shows movements first time during fifth month pregnancy. Embryo's heart is formed after the first month pregnancy.

The milk produced during the initial few days of lactation is called colostrum which contains several antibodies absolutely essential to develop resistance for the new born babies.

In test tube baby or in vitro fertilisation technique, the ovum is fertilised with the sperm outside the body of a woman providing the ovum with the same environmental conditions as it would have got inside the uterus. The zygote formed is grown inside a culture and when embryo (having 8 or more blastomeres) is formed, it is then implanted into uterus where it develops into foetus.

Line in NCERT: "In Vitro fertilisation followed by transfer of embryo into the female genital tract is one such method and is commonly known as the Test Tube Baby' Programme."

Inability to conceive or produce children even after unprotected sexual intercourse is called infertility. Specialised infertility clinics can help in diagnosis and proper treatment of infertile couples. But, when such treatment is not possible, the couples can be assisted to have children through certain special techniques called assisted reproductive technologies (ART).

Line in NCERT: "the couples could be assisted to have children through certain special techniques commonly known as assisted reproductive technologies (ART)."

Saheli is an oral pill that contains a non-steroidal preparation called centchroman. It is taken once a week after an initial intake of twice a week dose for 3 months. It hs high contraceptive value with very little side effects. It has been developed at Central Drug Research Institude, Lacknow.

The yeast Saccharmyces cerevisiae, also known as brewer's yeast, is used for fermenting malted cereals an fruit juices to produce ethanol (ethyl alcohol). Microbes (yeasts in particular) have been used for the production of beverages, such as wine, beer, whisky, brandy and rum.

• A cloning vector with two antibiotic resistance genes (for tetracycline and ampicillin) allows differentiation between recombinant and non-recombinant cells.
• Foreign DNA insertion disrupts the tetracycline resistance gene, so recombinants lose resistance to tetracycline but retain resistance to ampicillin.
• Non-recombinants (without foreign DNA insertion) retain both tetracycline and ampicillin resistance, allowing them to survive on a medium containing both antibiotics.

In this, a recombinant DNA is inserted within the coding sequence of an enzyme, β-galactosidase. This results into inactivation of the gene for synthesis of this enzyme, which is referred to as insertional inactivation. The presence of a chromogenic substrate gives blue coloured colonies if the plasmid in the bacteria does not have an insert. Presence of insert results into insertional inactivation of the β-galactosidase gene and the colonies do not produce any colour, these are identified as recombinant colonies.

The separated DNA fragments can be visualised only after staining the DNA with a compound known as ethidium bromide followed by exposure to UV radiation (you cannot see pure DNA fragments in the visible light and without staining). You can see bright orange coloured bands of DNA in a ethidium bromide stained gel exposed to UV light.

PCR and RFLP are the methods used for genetic fingerprinting. DNA fragmentation plays an important part in forensics, especially that of DNA profiling. Restriction fragment length polymorphism (RFLP) analyses the variable lengths of DNA fragments which are formed from the digestion of a DNA sample with a restriction endonuclease. They are then hybridized with DNA probes that bind to a complementary DNA sequence in the sample. In polymerase chain reaction (PCR), This sample DNA is amplified from a single copy to millions of copies of DNA. It used to amplify a specific region of a DNA strand. Most PCR methods amplify DNA fragments of between 0.1 and 10 kilo base pairs (kb), although some techniques allow amplification of fragments up to 40 kb in size.
 

Bacillus thuringiensis is not used as a bio-fertitiser but it is used to create transgenic plants.

Very low count of bacteria or viruses (when the symptoms of the disease are not yet visible) cab be detected by multiplication of their nucletic acid by PCR (PCR can detect very low amounts of DNA). PCR is usually used to detect HIV in suspected AIDS patients.

Topic in NCERT: Molecular diagnosis

Line in NCERT: "pcr is now routinely used to detect hiv in suspected aids patients."

The impacts of introducing a non-native or invasive species to an ecosystem will vary depending on a number of factors.

In some instances, the introduced species may not survive. If there is no ecological niche for the species to fill or the species cannot adapt to fill a different ecological niche, the species will likely go extinct relatively quickly at the local level.

However, if the species is a generalist, or a species able to thrive in a variety of environments and consume many food sources, that species will likely do well. If the ecosystem has reached its stable state, this means that the invasive species will have to replace a native species. No two species can share the same ecological niche, thus one will be better adapted and survive. If the invasive species is better adapted, it will out compete the native species.

If the species reproduces quickly, it is also more likely to thrive in a new ecosystem. If it can reproduce and grow faster than its competitor, it will eventually out compete that species.

Typically, invasive species harm an ecosystem. For example, the Burmese python is found in the US but it isn't supposed to be here. These snakes were likely released by humans and were pets at one time. The environment is suitable for them and they have adapted to the area.

Introducing a new species can also introduce any diseases that species has. These new diseases can spread to other native species and negatively affect them.

Introducing exotic species into new areas will increase competition for food and space. Sometimes, exotic species brings disease along with them. Exotic species in new area do not lead to extinction of native species.

To match the correct individual with their contribution or hypothesis, let's review each person listed along with the contributions mentioned:
Robert May is best known for his pioneering work in theoretical ecology, particularly in the areas of population dynamics and stability in ecological communities. However, none of the choices directly mention these specific contributions. Among the options, the closest (though indirect) could be his theoretical work that touch upon aspects like species diversity estimations.
Alexander von Humboldt, known for his extensive work in biogeography, made critical observations on the geographic distributions of species. His work best correlates with the "Species-Area relationship," which describes how the number of species increases with the area surveyed.
Paul Ehrlich is famous for his work on population studies and environmental issues facing humanity. His statement about the planet's carrying capacity and potential biodiversity loss is widely known. The "Global species diversity at about 7 million" might closely relate to his biodiversity and population studies, though it's not his primary known work.
David Tilman is well-acclaimed for his experimental work on biodiversity and ecosystem productivity. The "Long term ecosystem experiment using outdoor plots" directly correlates with his experimental approach to studying the relationship between biodiversity and ecosystem functioning using field experiments.

Given these associations:
A (Robert May) might best fit with "Global species diversity at about 7 million" (III) though it's a rough fit.
B (Alexander von Humboldt) correlating with "Species-Area relationship" (I) is a much clearer connection.
C (Paul Ehrlich) and the "Global species diversity at about 7 million" (II) matches if we consider his general scope in biodiversity and population dynamics.
D (David Tilman) with "Long term ecosystem experiment using out door plots" (II) is an exact match for his field of work.

Looking at the options provided,
Option B: A-III, B-I, C-IV, D-II
This option aligns correctly as per the reasoning.
Therefore, the correct answer is Option B.

Topic in NCERT: The section name from which the line is given is:

importance of species diversity to the ecosystem

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Species area relationship is the relationship between the area and the particular habitat. It is dependent on immigration, extinction and clustering etc. It was first studied by Alexander Von Humbolt.