Biology Mock Test- 5 - Class 9 MCQ

Both Amoeba and while blood cells of humans do not have any fixed shape.

Cell is the basic building block of all living organisms and perform all the activities required to sustain life. So, it is the structural and functional unit of life.

The medial rectus is an extraocular muscle that attaches to the side of the eye near the nose. It moves the eye inward toward the nose. The lateral rectus is an extraocular muscle that attaches to the side of the eye near the temple. It moves the eye outward.

 

Immunoglobulin A (IgA), as the principal antibody class in the secretions that bathe these mucosal surfaces, acts as an important first line of defence. IgA, also an important serum immunoglobulin, mediates a variety of protective functions through interaction with specific receptors and immune mediators. The importance of such protection is underlined by the fact that certain pathogens have evolved mechanisms to compromise IgA-mediated defence, providing an opportunity for more effective invasion. IgA function may also be perturbed in certain disease states, some of which are characterized by deposition of IgA in specific tissues. This review details current understanding of the roles played by IgA in both health and disease.

Plants absorb water from the soil by osmosis. Root hair cells are adapted for this by having a large surface area to speed up osmosis. The absorbed water is transported through the roots to the rest of the plant where it is used for different purposes: It is a reactant used in photosynthesis.

The western honey bee or European honey bee (Apis mellifera) is the most common of the 7–12 species of honey bee worldwide. The genus name Apis is Latin for "bee", and mellifera is the Latin for "honey-bearing", referring to the species' production of honey. Like all honey bees, the western honey bee is eusocial, creating colonies with a single fertile female (or "queen"), many normally non-reproductive females or "workers," and small proportion of fertile males or "drones."

Dr Verghese Kurien, Father of the White Revolution and man behind Amul. “Eight hours for dairy, eight hours for family and eight hours for sleep” – words from Dr Verghese Kurien who is known as the Father of the White Revolution. He is so called because of his initiatives and immense contribution to the dairy sector.

A broiler is any chicken that is bred and raised specifically for meat production. Many typical broilers have white feathers and yellowish skin. Most commercial broilers reach slaughter-weight between four and seven weeks of age, although slower growing breeds reach slaughter-weight at approximately 14 weeks of age.

Adipose tissue is a specialized connective tissue consisting of lipid rich cells called adipocytes.

R. Virchow in 1855 presented the idea that all cells arise from pre-existing cells. This was modification in the earlier cell theory.

In relatively large amounts, the soil supplies nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur; these are often called the macronutrients. Micronutrients are required by plants in far smaller quantities than any macronutrient. Micronutrients required by plants include zinc (Zn), iron (Fe), manganese (Mn), copper (Cu), boron (B), molybdenum (Mo), and chlorine (Cl). Relative to the macronutrients, micronutrients are required in trace quantities.

Soil supplies 13 essential nutrients for plant growth. These nutrients are divided into two categories:

Macronutrients:

1. Nitrogen (N)
2. Phosphorus (P)
3. Potassium (K)
4. Calcium (Ca)
5. Magnesium (Mg)
6. Sulfur (S)

Micronutrients:

1. Iron (Fe)
2. Manganese (Mn)
3. Boron (B)
4. Molybdenum (Mo)
5. Copper (Cu)
6. Zinc (Zn)
7. Chlorine (Cl)

These nutrients are crucial for various physiological functions and healthy plant development.

Oxygen is a component of many organic and inorganic molecules within the plant, and is acquired in many forms. Plants produce oxygen gas (O2) along with glucose during photosynthesis but then require O2 to undergo aerobic cellular respiration and break down this glucose to produce ATP.

The passage of water from a region of higher water concentration to lower concentration through a semi-permeable membrane is called osmosis.

Benefits of Developing Crop Varieties with Wider Adaptability:
1. Increased Stability in Crop Production:

• By developing crop varieties with wider adaptability, farmers can grow a single variety under different climatic conditions in various regions.


• This helps in stabilising crop production as the variety can withstand different environmental stresses and fluctuations.

2. Enhanced Resilience to Pests:

• Such varieties are likely to possess resistance to a wide variety of pests.


• This reduces the need for chemical pesticides and promotes sustainable agriculture practices.

3. Higher Yields:

• Crop varieties with wider adaptability are often bred to be higher yielding than many other varieties.


• This can lead to increased productivity and better economic returns for farmers.

4. Flexibility in Cultivation:

• With wider adaptability, farmers have the flexibility to grow the same variety under different climatic conditions.


• This reduces the risk of crop failure due to unpredictable weather patterns.

By developing crop varieties with wider adaptability, not only can crop production be stabilised, but farmers can also benefit from increased resilience, higher yields, and greater flexibility in cultivation practices.

Collenchyma: The cells have cell walls thickened at the corners due to pectin deposition.

Sclerenchyma: Their walls are thickened due to lignin deposition.

Explanation:

• Difference between mixed cropping and intercropping: Intercropping involves growing different crops in different rows alternating with each other, while mixed cropping involves growing two or more crops simultaneously on the same field without any distinct pattern.


• Benefits of intercropping: Intercropping reduces the risk of crop failure as different crops can provide insurance against the failure of one crop. This diversity can also lead to increased overall yield.


• Utilization of resources: Intercropping allows for efficient utilization of resources such as sunlight, water, and nutrients as different plants have different requirements and can complement each other in terms of resource utilization.


• Control of pests and diseases: Intercropping can help in reducing the incidence of pests and diseases as different crops can act as natural pest repellents to each other, reducing the need for chemical pesticides.


• Improvement of soil fertility: Intercropping can improve soil fertility as different crops can have different root structures and nutrient requirements, leading to better nutrient cycling in the soil.

By understanding the differences between mixed cropping and intercropping and the benefits of intercropping, farmers can make informed decisions on which cropping system to adopt based on their specific requirements and goals.

Protein synthesis involve formation of amino acid chain according to information present on DNA. Ribosomes provide site for protein synthesis.

Which body part is not composed of nervous tissue?
The correct answer is muscles.

Explanation:
The nervous tissue is responsible for transmitting signals throughout the body. It is found in various parts of the body, including the brain, spinal cord, and nerves. However, muscles are not composed of nervous tissue. They are made up of a different type of tissue known as muscle tissue.
Here is a detailed explanation:
1. Muscles: Muscles are responsible for movement and are composed of muscle tissue. Muscle tissue is made up of muscle fibers that contract and relax to produce movement. There are three types of muscles: skeletal muscles, which are attached to bones and allow voluntary movement; smooth muscles, which are found in the walls of organs and blood vessels and control involuntary movements; and cardiac muscles, which are found in the heart and control the heartbeat.
2. Nerves: Nerves are composed of nervous tissue and are responsible for transmitting signals between different parts of the body. They consist of nerve cells called neurons, which have the ability to generate and transmit electrical impulses. Nerves are found throughout the body and connect the brain and spinal cord to various organs and tissues.
3. Brain: The brain is the control center of the body and is composed of nervous tissue. It consists of billions of neurons that are responsible for processing and coordinating information from the senses, initiating and controlling movements, and regulating various bodily functions.
4. Spinal cord: The spinal cord is a long, cylindrical bundle of nervous tissue that extends from the base of the brain to the lower back. It is responsible for transmitting signals between the brain and the rest of the body. The spinal cord contains nerves that connect to different parts of the body and is protected by the bones of the spinal column.
In summary, while muscles play a crucial role in movement, they are not composed of nervous tissue. Nervous tissue is found in the brain, spinal cord, and nerves, which are responsible for transmitting signals throughout the body.

Epithelial Tissue Involved in Goitre:
The epithelial tissue involved in goitre is the Glandular epithelium. Here's why:
- Goitre is characterized by the enlargement of the thyroid gland, which is a part of the endocrine system.
- The thyroid gland is composed of follicles that produce, store, and release thyroid hormones.
- The cells lining the follicles are composed of glandular epithelium.
- Glandular epithelium is specialized for secretion and is found in glands throughout the body.
- In the thyroid gland, the glandular epithelial cells produce and secrete thyroid hormones, primarily thyroxine (T4) and triiodothyronine (T3).
- When the thyroid gland is not able to produce enough thyroid hormones, it can lead to an increase in the secretion of thyroid-stimulating hormone (TSH) by the pituitary gland.
- This excess TSH stimulates the growth and enlargement of the thyroid gland, resulting in goitre.
- The swelling in the throat region is caused by the increased size of the glandular epithelial cells and the increased blood flow to the enlarged thyroid gland.
In conclusion, the glandular epithelium is involved in goitre as it is responsible for the production and secretion of thyroid hormones, which can lead to the enlargement of the thyroid gland when there is an imbalance in hormone levels.

OSTEOBLASTS are the cells that form new bone. They also come from the bone marrow and are related to structural cells. They have only one nucleus.Osteoblasts work in teams to build bone. They produce new bone called "osteoid" which is made of bone collagen and other protein.

Importance of Bone Marrow
Bone marrow plays a crucial role in the production and maintenance of blood cells in the body. It is a spongy tissue found inside the bones, primarily in the long bones and the pelvic bones. The bone marrow contains stem cells that give rise to the different types of blood cells, including red blood cells (RBC), white blood cells (WBC), and platelets.
The importance of bone marrow can be understood by its functions related to blood cell production and maintenance:
1. Production of Red Blood Cells (RBC):
- The bone marrow is responsible for the continuous production of RBCs, which carry oxygen to different tissues and organs.
- RBCs are formed from stem cells in the bone marrow through a process called erythropoiesis.
- The bone marrow provides a suitable environment for the development and maturation of RBCs.
2. Production of White Blood Cells (WBC):
- The bone marrow is also involved in the production of different types of WBCs, which play a vital role in the immune system.
- WBCs defend the body against infections, foreign substances, and abnormal cells.
- Different types of WBCs, such as neutrophils, lymphocytes, monocytes, eosinophils, and basophils, are produced in the bone marrow.
3. Platelet Production:
- Platelets, also known as thrombocytes, are small cell fragments involved in blood clotting.
- The bone marrow produces platelets from stem cells, which are essential for the formation of blood clots to prevent excessive bleeding.
In summary, bone marrow is important for the production of RBCs, WBCs, and platelets, which are vital for oxygen transport, immune responses, and blood clotting.

Haversian system (named for Clopton Havers) is the fundamental functional unit of much compact bone. Osteons are roughly cylindrical structures that are typically several millimeters long and around 0.2 mm in diameter. They are present in many bones of most mammals and some bird, reptile, and amphibian species.

Because rats do not cause harm to the plants whereas bacteria,fungi and viruses cause diseases in plants..

The pigeon pea is a perennial legume from the family Fabaceae. Since its domestication in the Indian subcontinent at least 3,500 years ago, its seeds have become a common food in Asia, Africa, and Latin America.

The cell nucleus was discovered by Antonie van Leeuwenhoek in the 18th century. He first observed its structure in a sample of salmon blood. However, its intricate details were furnished by Robert Brown in the year 1831.

Explanation: Thigh muscles (skeletal muscles) can get tired because they are designed for short-term, powerful contractions and are under voluntary control. Heart muscles, on the other hand, are designed for continuous contractions and are involuntary muscles. However, the reason thigh muscles get tired is not simply because they are voluntary while heart muscles are involuntary.

The primary reason for this difference is due to the energy supply and metabolism of these muscle types. Skeletal muscles, like the thigh muscles, rely on both aerobic and anaerobic metabolism for energy production. During periods of intense activity, they can quickly run out of energy and produce lactic acid, leading to fatigue and muscle cramps.

Heart muscles, on the other hand, have a very high density of mitochondria and a rich supply of blood, ensuring a continuous supply of oxygen and nutrients. This allows them to generate energy through aerobic metabolism constantly and efficiently, preventing fatigue.

Both assertion and reason are true and reason is the correct explanation of assertion. Where absorption and secretion occur, such as in the inner lining of the intestine, tall epithelial cells or columnar epithelium is present. This epithelium facilitates movement or diffusion across the epithelial barrier.

Pearl culture which is not a very old venture is restricted to certain parts of the world only. It includes the culture of oysters in restricted areas and after attaining a particular size and treated specially with the help of scientific equipments and appliances to produce pearl.

Many times fish culture also known as pisciculture done in combination with rice crop. 

this is because during the sowing of rice crop it needs more and more water . the land where to sown the rice crop should be too much wet . even the field is filled with water up to 1 to 1.5 feet . so , in this water we can rear the fish also cause water is enough for fish and rice too. 

this water helps to. survive the new fishes in the field and when this fishes grown up than it will be transfer to a big lake or a pond .