Day: January 12, 2025

MCQs with Answers, Explanations, and Tips

1. A higher level of organization exhibits emergent properties when:

Options:
a) Its parts function independently.
b) The sum of its parts is greater than the whole.
c) Its individual parts are more important than the whole.
d) Its parts interact to perform more functions.

Correct Answer: d) Its parts interact to perform more functions.

Explanation:
Emergent properties arise when individual components of a system interact to create functions or characteristics that are not present in the individual parts alone.

Tip:
Think of “emergence” as something greater than the sum of its parts, like teamwork in a system.

2. Which of the following demonstrates the levels of organization of the body, from simplest to most complex?

Options:
a) Cell → Organ → Tissue → Organelle → Organ system
b) Organelle → Cell → Tissue → Organ → Organ system
c) Tissue → Cell → Organelle → Organ → Organ system
d) Organ system → Tissue → Cell → Organelle → Organ

Correct Answer: b) Organelle → Cell → Tissue → Organ → Organ system

Explanation:
The correct order of organization in the body progresses from the smallest functional unit (organelle) to the largest (organ system).

Tip:
Memorize the hierarchy: “Organelle → Cell → Tissue → Organ → Organ System → Organism.”

3. At which level of organization does gas exchange occur between body and environment?

Options:
a) Organelle level in mitochondria
b) Cellular level in alveolar cells
c) Tissue level in epithelial tissues
d) Organ system level in the respiratory system

Correct Answer: d) Organ system level in the respiratory system

Explanation:
Gas exchange involves the respiratory system, particularly the lungs and alveoli, which function at the organ system level.

Tip:
Gas exchange is a system-wide process involving specialized organs like lungs.

4. The epithelial tissue in the stomach wall is responsible for producing:

Options:
a) Mucus
b) Pepsinogen
c) Hydrochloric acid
d) All of these

Correct Answer: d) All of these

Explanation:
The epithelial tissue of the stomach secretes mucus (protective layer), pepsinogen (enzyme precursor), and hydrochloric acid (to aid digestion).

Tip:
Remember that epithelial tissues in the stomach are multifunctional and secrete various substances critical for digestion.

5. In the wall of the stomach, which tissue also contains blood vessels and nerves?

Options:
a) Epithelial
b) Muscle
c) Inner connective
d) Outer connective

Correct Answer: c) Inner connective

Explanation:
Connective tissue in the stomach wall supports blood vessels and nerves, providing structural integrity and communication.

Tip:
Connective tissue “connects” and supports other tissues, including blood vessels and nerves.

6. In a leaf, which tissue is primarily responsible for photosynthesis?

Options:
a) Xylem
b) Phloem
c) Mesophyll
d) Epidermis

Correct Answer: c) Mesophyll

Explanation:
The mesophyll tissue contains chloroplasts, which carry out photosynthesis in plant leaves.

Tip:
Think of “meso” (middle) as the layer in the leaf where most photosynthesis occurs.

7. What is the primary function of the xylem tissue in a leaf?

Options:
a) To transport sugars to other parts
b) To transport water to parts of leaf
c) To synthesize chlorophyll
d) To control the opening and closing of stomata

Correct Answer: b) To transport water to parts of the leaf

Explanation:
Xylem is responsible for conducting water and dissolved nutrients from the roots to the leaves.

Tip:
Xylem = Water transport, while phloem = Food transport.

8. Which of these is a function of the human skeletal system?

Options:
a) Storing minerals and producing blood cells
b) Protecting internal organs
c) Filtering blood to remove waste products
d) Both a and b

Correct Answer: d) Both a and b

Explanation:
The skeletal system protects internal organs, stores minerals (like calcium), and produces blood cells in the bone marrow.

Tip:
Think of the skeletal system as a “protector” and a “reservoir” for minerals and blood production.

Question 9:

Statement: Which structures are responsible for the transport of food in plant bodies?
Options:
a) Xylem tissue
b) Palisade mesophyll
c) Phloem tissue
d) Spongy mesophyll

Answer: c) Phloem tissue

Explanation: Phloem tissue is responsible for the transport of food (in the form of sugars) produced during photosynthesis from the leaves to other parts of the plant. Xylem, on the other hand, is involved in transporting water and minerals.

Tips and Tricks:

• Xylem transports “water.” Think of ‘X’ for “Xtra hydration.”
• Phloem transports “food.” Think of ‘P’ for “Photosynthetic Products.”

Question 10:

Statement: In a plant, which of the following is the primary function of the flower?
Options:
a) Transporting water and minerals
b) Supporting leaf growth
c) Facilitating reproduction through pollination
d) Regulating gas exchange

Answer: c) Facilitating reproduction through pollination

Explanation: The flower’s main role is reproduction. It produces gametes, facilitates pollination, and forms seeds and fruits for the propagation of plants.

Tips and Tricks:

• Remember: Flowers = Reproduction. They are like the “factories” of new plants.
• Other processes like water transport, leaf support, and gas exchange are not related to flowers.

Short Questions with Answers:

1. Enlist the levels of organization from cells to organ systems.
   Answer:
   • Cells → Tissues → Organs → Organ Systems → Organism
2. What are the major roles of the epithelial tissue present in the stomach?
   Answer:
   • Protection: Lines the stomach to prevent damage from digestive acids.
   • Secretion: Produces mucus, enzymes, and hydrochloric acid.
   • Absorption: Assists in absorbing nutrients from food.
3. How do the smooth muscles contribute to the stomach’s function?
   Answer:
   • Smooth muscles help in churning and mixing food with digestive enzymes and acids through peristaltic movements, aiding in digestion.
4. What is the function of the palisade mesophyll in the leaf?
   Answer:
   • The palisade mesophyll is the primary site for photosynthesis due to the abundance of chloroplasts that capture sunlight.
5. What is the role of the shoot system in plants?
   Answer:
   • The shoot system is responsible for supporting the plant, transporting water and nutrients, photosynthesis (leaves), and reproduction (flowers).
6. What is homeostasis, and why is it important for organisms?
   Answer:
   • Homeostasis is the process by which organisms maintain a stable internal environment (e.g., temperature, pH, water balance). It is essential for optimal functioning of cells and survival.
7. How does the human body maintain a stable internal temperature?
   Answer:
   • The body maintains temperature through mechanisms like sweating (to cool down), shivering (to generate heat), and blood flow regulation (vasodilation or vasoconstriction).
8. Differentiate between the following:
   • Tissue and organ:
     Tissue: A group of similar cells performing a specific function.
     Organ: A structure made up of different tissues working together to perform a specific function.
   • Root system and shoot system:
     Root system: Underground part of the plant, absorbs water and nutrients.
     Shoot system: Above-ground part of the plant, supports photosynthesis and reproduction.
   • Epidermal and mesophyll tissue:
     Epidermal tissue: Outer protective layer of the leaf.
     Mesophyll tissue: Inner tissue responsible for photosynthesis.
   • Palisade and spongy mesophyll:
     Palisade mesophyll: Tightly packed cells for maximum light absorption during photosynthesis.
     Spongy mesophyll: Loosely packed cells for gas exchange.

Long Questions with Answers:

1. Explain the levels of organization in multicellular organisms. How does each level contribute to the overall functioning of an organism?
   Answer:
   • Cells: Basic structural and functional units of life. E.g., nerve cells transmit signals.
   • Tissues: Groups of similar cells working together. E.g., muscle tissue contracts for movement.
   • Organs: Structures made of tissues performing specific tasks. E.g., the heart pumps blood.
   • Organ systems: Groups of organs working together. E.g., the digestive system processes food.
   • Organism: The entire living being, a sum of all systems working in harmony.
2. What is a tissue level? Explain plant and animal tissues.
   Answer:
   • Tissue level: The organization where cells perform a common function.
   • Plant tissues:
     • Meristematic tissues: Growth tissues.
     • Permanent tissues: For transport (xylem, phloem), protection (epidermis), and storage (parenchyma).
   • Animal tissues:
     • Epithelial: Protection and secretion.
     • Muscle: Movement.
     • Connective: Support and binding.
     • Nervous: Signal transmission.
3. Describe the tissue composition of the stomach. How does each tissue contribute to the digestive function of the stomach?
   Answer:
   • Epithelial tissue: Lines the stomach, secretes mucus, enzymes, and acids.
   • Muscle tissue: Smooth muscles churn food for digestion.
   • Connective tissue: Supports and binds stomach layers.
   • Nervous tissue: Regulates secretion and movement.
4. Describe the tissue composition of the leaf. How does each tissue contribute to the functions of the leaf?
   Answer:
   • Epidermal tissue: Protects the leaf and controls water loss through stomata.
   • Mesophyll tissue: Palisade mesophyll for photosynthesis, spongy mesophyll for gas exchange.
   • Vascular tissue: Xylem transports water; phloem transports food.
5. How do organ systems come together to form the human body?
   Answer:
   Organ systems are interdependent:
   • The digestive system provides nutrients.
   • The respiratory system supplies oxygen.
   • The circulatory system transports oxygen and nutrients.
   • The nervous system coordinates actions.
     Together, they maintain homeostasis and ensure survival.
6. Explain the roles of the digestive system and the excretory system in maintaining homeostasis.
   Answer:
   • Digestive system: Breaks down food to provide nutrients and energy for cells.
   • Excretory system: Removes waste products like urea and excess water to prevent toxicity.
     Together, they regulate the internal environment, maintaining balance.
7. Define homeostasis and explain its importance. Discuss how different organ systems work together to maintain homeostasis.
   Answer:
   • Homeostasis: The maintenance of a stable internal environment.
   • Importance: Ensures optimal conditions for cellular function.
   • Examples of systems working together:
     • Nervous and endocrine systems: Regulate temperature and glucose levels.
     • Respiratory and circulatory systems: Maintain oxygen and carbon dioxide balance.
     • Excretory and integumentary systems: Regulate water and salt balance.