Olympiad Test: Nutrition In Plants And Animals -1 - Class 7 MCQ

Nutrients are substances present in food
There are several types of nutrients that are essential for the human body to function properly. These nutrients can be found in various types of food and are necessary for growth, development, and maintenance of overall health. Here are some key points to understand about nutrients:
1. Definition of nutrients:
- Nutrients are substances that provide nourishment to the body.
- They are essential for the growth, development, and maintenance of the body.
2. Types of nutrients:
- Macronutrients: These are nutrients required in large amounts and include carbohydrates, proteins, and fats.
- Micronutrients: These are nutrients required in smaller amounts and include vitamins and minerals.
- Water: Although not technically a nutrient, water is essential for hydration and plays a vital role in bodily functions.
3. Sources of nutrients:
- Food: Nutrients are primarily obtained from the food we consume.
- Different types of food contain different nutrients. For example, fruits and vegetables are rich in vitamins and minerals, while meat and legumes are good sources of protein.
4. Functions of nutrients:
- Carbohydrates: Provide energy for the body.
- Proteins: Build and repair tissues, support the immune system, and act as enzymes and hormones.
- Fats: Provide energy, insulation, and protection for organs.
- Vitamins: Help regulate metabolism, support growth and development, and aid in various physiological processes.
- Minerals: Essential for the formation of bones and teeth, nerve function, and enzyme activity.
- Water: Facilitates digestion, nutrient absorption, and waste elimination.
In conclusion, nutrients are substances present in food that are essential for the body's growth, development, and maintenance. They can be obtained from a variety of food sources and play vital roles in various physiological processes.

Saprophytes obtain their food from:
Saprophytes are organisms that obtain their nutrition from dead or decaying organic matter. They play an important role in the decomposition and recycling of organic material in ecosystems. Specifically, they obtain their food from:
- Decaying wastes: Saprophytes feed on decaying organic matter, such as dead plants, leaves, wood, and animal carcasses. They break down these materials into simpler compounds and absorb the nutrients they need for growth and reproduction.
- Nongreen plants: Saprophytes can also obtain their food from non-photosynthetic plants, such as fungi and some bacteria. These organisms derive their energy and nutrients from the breakdown of organic matter rather than through photosynthesis.
- All of these: The correct answer is option D, as saprophytes obtain their food from decaying wastes, nongreen plants, and other sources of dead or decaying organic matter.
Saprophytes play a crucial role in nutrient cycling and the decomposition process. They help break down complex organic compounds into simpler forms, releasing nutrients back into the environment for other organisms to use. Without saprophytes, dead organic matter would accumulate, and nutrients would become locked up and unavailable for use by other organisms.

Raw materials used for photosynthesis are:
- Carbon dioxide: Carbon dioxide is a gas that is essential for photosynthesis. It is obtained from the atmosphere through tiny pores called stomata present in the leaves of plants.
- Water: Water is another crucial raw material required for photosynthesis. It is absorbed by the roots of the plants from the soil and transported to the leaves through the xylem vessels.
- Both (a) and (b): Carbon dioxide and water are both necessary for the process of photosynthesis to occur. They are the primary raw materials that plants use to produce glucose and oxygen.
- None: This option is incorrect as both carbon dioxide and water are essential for photosynthesis. Without these raw materials, plants would not be able to carry out the process and produce food.
In conclusion, the correct answer is option C: both (a) and (b), as carbon dioxide and water are the raw materials used for photosynthesis.

Explanation:
Leaves have a network of veins to transport materials in them. The correct pair to compare this network of veins with is:
A: veins : road
- This comparison is correct as veins in leaves are  similar to roads.
B: veins : pavement
- This comparison is incorrect as veins in leaves are not similar to pavements.
C: veins : speed breaker
- This comparison is incorrect as veins in leaves are not similar to speed breakers.
D: veins : bridge
- This comparison is incorrect as veins in leaves are not similar to bridges.
Therefore, the correct pair is option A: veins : road.

Plants get nitrogen from soil.
Explanation:
- Nitrogen is an essential nutrient for plants as it is a key component of proteins, nucleic acids, and chlorophyll.
- While some plants can obtain nitrogen from the air through a process called nitrogen fixation, the majority of plants acquire nitrogen from the soil.
- Nitrogen in the soil exists in various forms, such as organic matter, ammonium (NH4+), and nitrate (NO3-).
- Plants can absorb nitrogen in the form of ammonium or nitrate through their roots.
- Once inside the plant, nitrogen is utilized for various metabolic processes, including growth and development.
- Nitrogen is often a limiting nutrient in soil, meaning that its availability can influence plant growth and productivity.
- To ensure an adequate supply of nitrogen, farmers may use fertilizers or cultivate nitrogen-fixing crops to enrich the soil with nitrogen.
- In conclusion, while plants can obtain nitrogen from the air through nitrogen fixation, the primary source of nitrogen for plants is the soil.

Soil in which insectivorous plants grow is deficient in

The correct answer is C: nitrogen.
Insectivorous plants have adapted to grow in nutrient-poor environments, and they have evolved to obtain nutrients, particularly nitrogen, from insects they capture and digest. Here is a detailed explanation:

Explanation:

Nutrient requirements of plants:

- Plants require various nutrients for their growth and development.
- These nutrients are classified into macronutrients and micronutrients.
- Macronutrients are required in larger quantities, while micronutrients are required in smaller quantities.

Nitrogen deficiency:

- Nitrogen is one of the essential macronutrients required by plants.
- It is a vital component of amino acids, proteins, nucleic acids, and chlorophyll.
- Nitrogen is necessary for plant growth, leaf development, and overall plant health.
- Insectivorous plants have adapted to grow in nitrogen-deficient soils.

Adaptation of insectivorous plants:

- Insectivorous plants have evolved to obtain nitrogen from insects they capture.
- They have specialized structures such as sticky leaves, pitcher-like traps, or snap traps that capture and digest insects.
- The plants then absorb the nutrients, including nitrogen, from the digested insects.
- This adaptation allows insectivorous plants to survive in nitrogen-deficient environments.

Other nutrient deficiencies:

- While nitrogen deficiency is the most significant nutrient deficiency in the soil where insectivorous plants grow, they may also face other nutrient deficiencies.
- However, these deficiencies are not specific to insectivorous plants and can occur in other plant species as well.
- Phosphorus and sulfur are also essential macronutrients required by plants, but their deficiency is not specific to insectivorous plants.
- Therefore, option C, which states that the soil is deficient in nitrogen, is the correct answer.
In conclusion, insectivorous plants have adapted to grow in nitrogen-deficient soils. They obtain nitrogen from insects they capture and digest, allowing them to thrive in nutrient-poor environments.

Explanation:
The correct photosynthetic equation is option B: Carbon dioxide + water → Oxygen + food. Here is the detailed explanation:
Photosynthesis:
Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy from the sun into chemical energy in the form of glucose (food). It is a vital process for the survival of most organisms on Earth.
Photosynthetic Equation:
The photosynthetic equation represents the overall process of photosynthesis. It shows the reactants and products involved in the process.
The correct photosynthetic equation is as follows:
Carbon dioxide + water → Oxygen + food
Explanation of each component:
- Carbon dioxide (CO2): It is a gas present in the atmosphere. Plants take in carbon dioxide from the air through tiny openings called stomata on their leaves.
- Water (H2O): Plants absorb water from the soil through their roots. Water is transported to the leaves where it is used in the photosynthesis process.
- Oxygen (O2): Oxygen is a byproduct of photosynthesis. It is released into the atmosphere through the stomata.
- Food (Glucose): During photosynthesis, plants produce glucose, which is a simple sugar. Glucose is stored in various parts of the plant, providing energy for growth and other metabolic processes.
Conclusion:
The correct photosynthetic equation is Carbon dioxide + water → Oxygen + food. This equation represents the process by which plants convert carbon dioxide and water into oxygen and glucose through the process of photosynthesis.

Cuscuta is a parasitic plant. It lack chlorophyll hence it appears as yellow tubular structure and obtains its food from its host mulberry. Cactus are not parasitic plants. Cacti are succulent plants that belong to the Cactaceae family.

Croton plants have chlorophyll but other red pigments are more in number than the chlorophyll so they are not in green colour they can perform photosynthesis. 

Housefly takes its food by sponging.
- Houseflies have a specialized mouthpart called a proboscis, which is like a sponge.
- They do not bite or chew their food like other insects.
- The proboscis is used to sponge up liquid food.
- Houseflies are attracted to various sources of liquid food such as decaying organic matter, sugary substances, and even animal feces.
- When they find a suitable food source, they extend their proboscis and suck up the liquid food.
- The proboscis is equipped with tiny hair-like structures that help in absorbing the liquid.
- The housefly's digestive system is adapted for processing liquid food.
- Once the food is sucked up, it enters the fly's digestive system, where it is broken down and absorbed.
- Houseflies are also known to regurgitate digestive juices onto their food to help dissolve it before sucking it up.
- This unique feeding behavior allows houseflies to efficiently obtain nutrients from their food sources.
Therefore, the correct answer is C: sponging.

Teeth used to grind the apple in the mouth are:
- Premolars and molars: These teeth have flat surfaces with ridges, which are ideal for grinding and chewing food.
- Incisors: Incisors are the front teeth used for cutting and biting into food. While they may play a role in initially breaking down the apple, they are not primarily responsible for grinding.
- Canines: Canines are the pointed teeth located next to the incisors. They are designed for tearing and gripping food, rather than grinding.
- Molars: Molars are the back teeth used for grinding food. They have large, flat surfaces with multiple cusps that help break down and grind food.
Therefore, the correct answer is Premolars and molars (option C). These teeth are specifically adapted for grinding and chewing solid foods like apples.

Correct Answer :- d

Explanation : Cellulose forms the large part of the undigested matter we egest. It is the substance the 'cell wall' of the plant is made of. They are highly complex in nature and are ejected from the body undigested.  

Certain herbivorous animals like cow, goat are capable enough to digest the cellulose because they have better enzyme support reactions occurring in them. They are capable enough to undergo the digestion and eject the undigested food.

The portion of tongue used to taste sweetness is the tip.
The tongue is responsible for detecting different tastes through taste buds located on its surface. While it is a common misconception that certain tastes are exclusively detected by specific areas of the tongue, the truth is that taste buds are distributed evenly across the entire tongue. However, certain tastes may be more prominent in specific areas due to the concentration of taste buds.
Here is a breakdown of the taste buds and their distribution on the tongue:
1. Sweetness:
- The taste buds responsible for detecting sweetness are located on the tip of the tongue.
- These taste buds are most sensitive to sugars and other sweet substances.
- When we consume foods or drinks with a high sugar content, the taste buds on the tip of the tongue send signals to the brain, allowing us to perceive the taste of sweetness.
2. Other tastes:
- The taste buds for other tastes, such as sourness, saltiness, bitterness, and umami, are distributed across the entire surface of the tongue.
- While the tip of the tongue may be more sensitive to sweetness, it can also detect other tastes to some degree.
Overall, the perception of sweetness is not limited to the tip of the tongue, but it is most prominent in that area due to the concentration of taste buds.

Food Factories of the Plant
Introduction:
The term "food factories of the plant" refers to the specific plant organs that are responsible for photosynthesis, the process by which plants convert sunlight into energy-rich carbohydrates. These carbohydrates serve as the primary source of food for the plant.
Leaves:
Leaves are the primary food factories of the plant. They contain specialized cells called chloroplasts that contain chlorophyll, a pigment essential for photosynthesis. Leaves are well-adapted for absorbing sunlight and exchanging gases through tiny openings called stomata. They play a crucial role in converting carbon dioxide and water into glucose and oxygen.
Stem:
While the stem is not considered the primary food factory of the plant, it does have some photosynthetic capabilities. Green stems contain chloroplasts and can contribute to the plant's food production. However, their role is generally secondary compared to the leaves.
Roots:
Roots do not typically function as food factories of the plant. Their primary role is to anchor the plant and absorb water and nutrients from the soil. Although some storage roots, such as carrots or sweet potatoes, may contain stored carbohydrates for future use, they are not involved in significant photosynthesis.
Flowers:
Flowers are not typically considered food factories of the plant. Their primary function is to facilitate reproduction by attracting pollinators. While flowers may contain some chlorophyll and carry out a minimal amount of photosynthesis, their role in food production is relatively insignificant compared to leaves.
Conclusion:
Among the options given, leaves are the primary food factories of the plant. They contain chlorophyll, which enables photosynthesis and the production of carbohydrates necessary for the plant's survival. While stems, roots, and flowers may have some limited photosynthetic capabilities, it is the leaves that play the most significant role in food production.

The digestion taking place in small intestine is extracellular digestion.