VITEEE PCBE Mock Test - 1 - JEE MCQ

Velamen is a vital part of certain plants, particularly epiphytes like orchids. It serves several important functions, including:

• Absorption of moisture: Velamen helps in capturing water from the atmosphere, which is essential for the plant's survival in its often dry, aerial environment.
• Protection: This layer acts as a barrier, shielding the delicate inner tissues of the plant from environmental damage and pathogens.
• Respiration: Velamen also plays a role in gas exchange, allowing the plant to take in oxygen and release carbon dioxide.
• Transpiration: It facilitates the loss of excess water through evaporation, helping to regulate the plant's internal moisture levels.

Overall, the velamen is crucial for the adaptability and health of epiphytic plants.

The larva of 'Culex' is typically found floating on the water's surface. Its head is positioned in a specific direction, which is important for its survival.

• The head of the larva is directed downwards.
• This orientation allows the larva to access oxygen efficiently.
• Being submerged while keeping its breathing tube at the surface helps it remain hidden from predators.
• Understanding this behaviour is crucial for studying the ecology of these insects.

Biological control is a modern approach to managing plant diseases, focusing on using natural methods rather than chemicals. This strategy involves:

• Utilising beneficial organisms that can naturally combat pests and diseases.
• Promoting the health of the ecosystem to reduce disease outbreaks.
• Implementing practices like crop rotation and intercropping to enhance biodiversity.

This method is increasingly favoured as it often poses less risk to the environment and human health compared to traditional chemical methods. By harnessing nature’s own mechanisms, farmers can achieve sustainable disease management.

Chlorophyll is a vital component in plants, responsible for the green colour and crucial for photosynthesis. The key element found in chlorophyll is magnesium (Mg). This metal plays an essential role in the structure of chlorophyll, allowing plants to absorb sunlight efficiently.

Here are some important points regarding magnesium and chlorophyll:

• Role of Magnesium: Magnesium is central to the chlorophyll molecule.
• Photosynthesis: It aids in the process where plants convert sunlight into energy.
• Deficiency Effects: A lack of magnesium can lead to yellowing of leaves, affecting plant health.

While other elements like manganese (Mn), zinc (Zn), and iron (Fe) are also important for plant growth, they do not form part of the chlorophyll structure. Instead, they serve different roles in plant metabolism and enzyme function.

High blood pressure can occur due to several factors:

• Increased sodium absorption: This can lead to higher blood pressure as it causes the body to retain more fluid.

• Decreased blood volume: Lower blood volume can sometimes trigger the body to raise blood pressure to maintain circulation.

• Decreased aldosterone release: Aldosterone helps regulate blood pressure; its reduction can affect pressure levels.

• Increased opening of capillary beds: This can allow more blood to flow through the vessels, potentially impacting blood pressure.

Agranal chloroplasts are a type of chloroplast found in certain plants.

• These chloroplasts are characterised by their lack of thylakoid membranes, which are typically present in most chloroplasts.
• Agranal chloroplasts are commonly found in plants that thrive in arid environments, such as some succulents.
• They are adapted for efficient photosynthesis under conditions where water is scarce.
• In addition to succulents, agranal chloroplasts can also be present in some aquatic plants, known as hydrophytes.
• These adaptations help plants maximise their light absorption while minimising water loss.

Overall, agranal chloroplasts play a key role in the survival of plants in challenging environments.

Cell organelles that are surrounded by a single unit membrane include:

• Glyoxysome: These organelles are found in plants and play a role in converting stored fats into sugars during seed germination.

• Lysosome: Known as the cell's waste disposal system, lysosomes contain digestive enzymes to break down waste materials and cellular debris.

• Peroxisome: These organelles are involved in the metabolism of fatty acids and the detoxification of harmful substances, including hydrogen peroxide.

All of these organelles share the characteristic of being enclosed by a single lipid bilayer membrane.

Cell recognition and adhesion are essential processes that enable cells to interact and communicate with one another. These processes primarily depend on specific molecules present in the cell membrane.

The main components involved in cell recognition and adhesion include:

• Proteins: These play a crucial role in facilitating interactions between cells.
• Lipids: While not directly responsible for recognition, they contribute to the membrane's structure.
• Glycoproteins: These are proteins with sugar molecules attached, vital for cell-to-cell recognition.
• Glycolipids: Similar to glycoproteins, these lipids also have sugar chains that assist in recognition.

Among these, glycoproteins and glycolipids are particularly important as they provide the identity markers that cells use to recognise each other, facilitating adhesion and communication.

If decomposers were to become extinct, the ecosystem would face significant challenges.

• Noncycling of minerals: Decomposers play a crucial role in breaking down organic matter, returning essential minerals to the soil. Their absence would lead to a depletion of these vital nutrients, disrupting plant growth.

• Damage to nitrogen fixation: Certain decomposers help in the process of nitrogen fixation, which is vital for plant health. Without them, the availability of nitrogen in the soil would decrease, negatively impacting agriculture and natural ecosystems.

• Biomagnification: While not directly linked, the absence of decomposers could contribute to increased levels of toxins in the food chain, leading to biomagnification, where toxins accumulate in higher concentrations in predators.

• Carnivores will be starved: The decline of herbivore populations due to poor plant growth would ultimately lead to starvation among carnivores, disrupting the entire food web.

Evidence of evolution can be observed through various types of organs, which provide insight into the relationships between different species. The main categories include:

• Homologous organs: These are organs that have a similar structure but may serve different functions in different species, indicating a common ancestor.
• Analogous organs: These organs serve similar functions but have different structures and origins, showing how different species can adapt to similar environments.
• Vestigial organs: These are remnants of organs that once had a function in ancestral species but are no longer functional in the current species, highlighting evolutionary changes over time.

All of these types of organs contribute to our understanding of evolutionary evidence, demonstrating how species change and adapt through time.

Homologous organs are organs that may look different but share a similar fundamental structure and origin. These organs arise from a common ancestor and are adapted to perform different functions in various species. Here are key points to understand about homologous organs:

• Common Origin: Homologous organs develop from the same embryonic tissue.
• Different Functions: While they may serve different purposes in different organisms, their structural similarities highlight evolutionary relationships.
• Examples: The forelimbs of humans, whales, and bats are classic examples, showcasing how these structures have adapted to diverse environments.

Understanding homologous organs is crucial in the study of evolution, as they provide insight into how species have evolved over time from common ancestors.

Forearm of humans and fins of fishes are examples of structures that are not homologous. This means that they do not share a common evolutionary origin despite possibly serving similar functions. Here’s a breakdown of the differences:

• Forearm of Humans: This structure is adapted for manipulation and grasping, featuring a complex arrangement of bones and muscles.
• Fins of Fishes: These are primarily used for swimming and are structured differently, focusing on propulsion and stability in water.

In contrast, the wings of bats and insects, as well as the fins of fishes and the flippers of whales, are considered homologous because they share a common evolutionary ancestor. Their structural similarities arise from this shared lineage, even though they have adapted to different environments.

• Wings of Bats: These are modified forelimbs with a bone structure similar to that of human arms.
• Wings of Insects: These have a different origin and structure but perform a similar function of flight.
• Fins of Fishes: These are distinct from the forelimbs of mammals, showing adaptation to aquatic life.
• Flippers of Whales: These are modified limbs that share a common ancestor with land mammals but have evolved for life in water.

Somaclonal variation is a process that leads to genetic changes in plants, often resulting from tissue culture techniques. This variation can be induced through several methods, which include:

• Tissue culture: This is the primary method used to generate somaclonal variation. It involves growing plant cells in a controlled environment, allowing for the development of new traits.
• Application of colchicine: Colchicine is a chemical that disrupts cell division, which can lead to polyploidy, a condition where cells have more than two paired sets of chromosomes. This can enhance genetic diversity.
• Irradiation with gamma rays: This method exposes plants to gamma radiation, which can induce mutations. These mutations can result in new traits that may be beneficial for cultivation.

Among these methods, the most common and effective way to obtain somaclonal variation is through tissue culture.

Pneumococcus experiment provides crucial insights into genetics and bacterial reproduction:

• The experiment demonstrates that DNA is the genetic material responsible for inheritance in organisms.

• It shows that bacteria reproduce through a process known as binary fission, where one cell divides into two identical cells.

• This evidence indicates that bacteria do not reproduce sexually, unlike many other organisms.

• Additionally, it suggests that under certain conditions, RNA can regulate the production of DNA and proteins.

Of the 64 codons, 61 are responsible for coding 20 types of amino acids. This phenomenon occurs due to:

• Degeneracy of the genetic code: This means that multiple codons can specify the same amino acid, allowing for a more flexible coding system.

To elaborate:

• Codons are sequences of three nucleotides in DNA or RNA.
• There are 64 possible codons (4 nucleotide bases raised to the power of 3).
• However, only 61 codons directly code for amino acids, while the remaining 3 are stop codons that signal the end of protein synthesis.
• This degeneracy ensures that even if a mutation occurs in the DNA sequence, the resulting protein may still function correctly because multiple codons can code for the same amino acid.

Plasmids are small, circular pieces of DNA found in many bacteria and some other organisms. They play an important role in genetic processes. Here are their key functions:

• Genetic Material: Plasmids contain genes that can provide advantages to the organism, such as antibiotic resistance.
• Replication: They can replicate independently of the chromosomal DNA, allowing for rapid reproduction of their genetic information.
• Genetic Engineering: Scientists use plasmids as tools in genetic engineering to introduce new genes into organisms.
• Transfer of Traits: Plasmids can be transferred between bacteria, facilitating the spread of beneficial traits.

In summary, plasmids are vital components of microbial genetics, enhancing survival and adaptability.

Epistasis is a genetic phenomenon where the effect of one gene is influenced by another gene. This interaction occurs when:

• Two different genes are located on different loci within the same chromosome or on different chromosomes.
• The genes interact in such a way that one gene can mask or modify the expression of another gene.
• This relationship can affect traits and phenotypes, leading to variations that are not predictable by examining each gene individually.

In summary, epistasis primarily results from the interaction of genes that are not located on the same loci.

Amniocentesis is a procedure used during pregnancy to obtain a sample of amniotic fluid for testing. The presence of an extra barr body in the embryo indicates a genetic anomaly that could lead to specific syndromes.

In this case, the likely syndrome that may occur in the child is:

• Klinefelter's syndrome - This occurs in males who have an extra X chromosome. The typical chromosomal pattern is XXY, leading to various physical and developmental issues.
• Down's syndrome - Caused by an extra copy of chromosome 21, resulting in developmental delays and characteristic facial features.
• Edward's syndrome - This syndrome involves an extra chromosome 18, leading to severe developmental and health issues.
• Patau's syndrome - It results from an extra chromosome 13, associated with serious congenital problems.

The presence of an extra barr body typically suggests a male with Klinefelter's syndrome, as females usually have two X chromosomes, while males have one. Thus, the most likely condition for the child in this scenario is Klinefelter's syndrome.

Duchenne's muscular dystrophy is a severe genetic disorder primarily affecting boys. It leads to progressive muscle degeneration and weakness. The prognosis for patients with this condition is generally poor, as most do not survive into adulthood.

• Symptoms usually appear in early childhood, typically between the ages of 2 and 6.
• As the disease progresses, patients may lose the ability to walk by their early teenage years.
• The average life expectancy for individuals with Duchenne's muscular dystrophy is around 20 years, though many live into their late teens.
• Advancements in care and treatment may improve quality of life and longevity slightly, but a cure has not yet been found.

Overall, while Duchenne's muscular dystrophy significantly impacts lifespan, ongoing research is focused on finding better therapies to extend life and improve the well-being of those affected.

An antibody is a type of protein produced by the immune system to help identify and neutralise foreign objects like bacteria and viruses. Antibodies play a crucial role in the body's defence mechanisms. Here are some key points about antibodies:

• They are specifically designed to inactivate antigens, which are substances that provoke an immune response.
• Antibodies bind to the antigens, marking them for destruction by other immune cells.
• These proteins are not components of red blood cells (RBCs) or general blood components.
• Each antibody is unique and tailored to recognise a specific antigen.

In summary, antibodies are essential molecules that play a vital role in the immune response by targeting and neutralising harmful invaders.

Total number of applicants shortlisted from college A, B and C = 0.4 x 1350 + 0.35 x 2300 + 0.6 x 1650 = 540 + 805 + 990 = 2335

Number of applications received by college A in years 2012, 2013 and 2014 = 1800 + 1500 + 1350 = 4650
Number of applications received by college B in years 2014, 2015 and 2016 = 2300 + 1600 + 2000 = 5900
Required percentage = (4650 x 100)/5900 = 78.81%

'T - P ÷ Q' means P is son of T, Q is sister of P.

Hence, Q is daughter of T.

'P of Q + R' means Q is the father of P, R is the daughter of Q.

Hence, R is the sister of P.

'L() M ÷ N' means M is mother of L, N is sister of M.

Hence, M and N are both sisters.

'Yx Z () K' means Z is the brother of Y, K is the mother of Z.

Hence, Z is the son of K.

Let the number of girls be 2x and number of boys be x.

Girls getting admission = 0.6x

Boys getting admission = 0.45x

Number of students not getting admission = 3x – 0.6x -0.45x = 1.95x

Percentage = (1.95x/3x) * 100 = 65%

The ratio of number of male and female journalists in a newspaper office is 5:4.

The newspaper has two sections, political and sports.

If 30 percent of the male journalists and 40 percent of the female journalists are covering political news, what percentage of the journalists (approx.) in the newspaper is currently involved in sports reporting?

Let ‘9x’ be the number of total journalists in the office.
Then, we can say that the number of male and female journalists are ‘5x’ and ‘4x’ respectively.

It is given that 30 percent of the male journalists and 40 percent of the female journalists are covering political news. Hence, total number of journalists who are covering political news = 0.3*5x + 0.4*4x = 3.1x

Therefore, the total number journalists who are covering sports news = 9x – 3.1x = 5.9x.
Hence, the percentage of the journalists in the newspaper is currently involved in sports reporting = 5.9x/9x x 100 ≈ 

65 percent. Therefore, option B is the correct answer.

Assume one person is born every day. In 100 years, there will be 25 leap years. So 25*1 additional people will be born on these days.
So, total people born will be = 365 x 100 x 1 + 25 x 1
And people born on 29th february = 25 x 1
Hence percentage will be 

Let ‘x’ be the strength of group G. Based on the information, 0.65x constitutes of literate people {the rest 0.35x = illiterate}
Of this 0.65x , 75% are old people =(0.75)0.65x old literates.
The total number of old people in group G is 0.72x  {72% of the total}.
Thus, the total number of old people who are illiterate = 0.72x - 0.4875x = 0.2325x.
This is 
≈ 66& of the total number of illiterates.
Hence, Option C is the correct answer.