Chapter 5: Tissues, Organs and Organs systems

Select the correct answer:

1. The diagram shows cells in part of the leaf of a green plant. Which region contains cells which are responsible for the process of transport? (Diagram of a leaf cross-section with labeled regions A, B, C, D)

Answer: C

Explanation: Region C represents the vascular tissue (veins) containing xylem and phloem, which are responsible for the transport of water, minerals, and sugars.

2. The table shows three functions of cells which row is correct?

Answer: B (Root hair cell: absorption; Xylem vessel: support; Red blood cell: transport)

3. What are the functions of xylem and phloem in green plants?

Answer: C (Xylem: support and transport of water; Phloem: transport of sugar)

4. If tissue level is not developed in the level of organization, which next level will not form?

A) Molecular level

B) atomic level

C) Organ level

D) organelle level

Answer: C) Organ level

Explanation: The levels of organization are: cells [source symbol unavailable] tissues [source symbol unavailable] organs [source symbol unavailable] organ systems [source symbol unavailable] organism. If tissues do not form, organs cannot form because organs are made of different tissues.

5. Following diagram shows level of organization in a rat. Which one is the organ level? (Diagram of a rat with labeled parts A, B, C, D)

Answer: The organ level is represented by a structure like the heart, liver, or kidney (likely one of the labeled parts in the diagram).

6. Which of the following lists the levels of body organization from smallest to largest?

A) organism, organ system, organ, tissue, cell

B) tissue, cell, organ, organ system, organism

C) organ, organ system, organism, tissue, cell

D) cell, tissue, organ, organ system, organism

Answer: D) cell, tissue, organ, organ system, organism

7. This statement about Homeostasis is incorrect:

A) because of this, the fluctuations of the internal environment are of extremely narrow range as compared to that of the external environment

B) there is one system regulating the homeostatic activities

C) homeostatic mechanisms keep the internal environment constant despite wide changes in the external environment

D) homeostasis is necessary for the survival of cells

Answer: B) there is one system regulating the homeostatic activities

Explanation: Homeostasis is regulated by multiple organ systems working together (nervous, endocrine, circulatory, etc.), not by a single system.

8. Which of the following statements best describes homeostasis?

A) keeping the body in a fixed and unaltered state

B) dynamic equilibrium

C) maintaining a near-constant internal environment

D) altering the external environment to accommodate the body's needs

Answer: C) maintaining a near-constant internal environment (or B: dynamic equilibrium)

9. Organisms have the ability to change and modify their internal conditions according to the environment through:

A) osmoregulation

B) excretion

C) thermoregulation

D) all of the above

Answer: D) all of the above

10. You can observe spongy mesophyll and xylem in the section of leaf. These are part of the same:

A) cell and organ

B) organ and organism

C) cell and tissue

D) tissue and organ

Answer: D) tissue and organ

Explanation: Spongy mesophyll is a tissue; xylem is a tissue. Both are part of the leaf, which is an organ.

11. The diagram shows a sample of material taken from an organism. (Diagram of a neuron with labeled parts: Nucleus, Dendrite, Axon, Nerve ending, Cell body) Which level of organization does the sample show?

A) cell

B) organ

C) organ system

D) tissue

Answer: A) cell

Explanation: The diagram shows a single neuron (nerve cell), which is the basic unit of the nervous system.

12. Which structure is not an organ?

A) artery

B) flower

C) spinal cord

D) xylem

Answer: D) xylem

Explanation: Xylem is a tissue, not an organ. Artery, flower, and spinal cord are organs.

13. Which description of xylem is correct?

A) a cell used for absorption

B) an organ system used for conduction

C) a tissue used for transport

D) an organ used for transport

Answer: C) a tissue used for transport

14. Which structure is at a different level of organization from the other three?

A) kidney

B) liver

C) neuron

D) lung

Answer: C) neuron

Explanation: Kidney, liver, and lung are organs. Neuron is a cell.

15. The diagram shows tissues from section of leaf. Which type of cells will perform photosynthesis? (Diagram of leaf tissues with labeled parts 1-6)

A) 1 and 4

B) 2 and 5

C) 2 and 3

D) 3 and 6

Answer: A) 1 and 4

Explanation: Parts 1 and 4 likely represent the palisade mesophyll and spongy mesophyll, which contain chloroplasts and perform photosynthesis.

1. Can you differentiate between:

(a) Organ and organelle

Answer: An organ is a group of tissues that work together to perform a specific function (e.g., heart, liver). An organelle is a

specialized structure within a cell that performs a specific function (e.g., mitochondria, ribosomes). Organs are made of tissues; organelles are made of macromolecules.

(b) Animal and plant tissues

Answer: Animal tissues include epithelial, connective, muscular, and nervous tissues. Plant tissues include meristematic and permanent tissues (epidermal, ground, vascular). Animal tissues often have more variety and are organized into organs and systems; plant tissues are more rigid and have cell walls.

(c) Xylem and phloem

Answer: Xylem transports water and minerals from roots to leaves and provides support. Phloem transports sugars from leaves to other parts of the plant. Xylem is mostly dead tissue; phloem is living tissue. Xylem is unidirectional; phloem is bidirectional.

(d) Epithelial and muscular tissue

Answer: Epithelial tissue covers body surfaces, lines cavities, and forms glands. Muscular tissue is specialized for contraction and movement. Epithelial tissue is composed of tightly packed cells; muscular tissue is composed of elongated, contractile cells.

(e) Nervous and connective tissue

Answer: Nervous tissue is specialized for transmitting electrical impulses (neurons and glial cells). Connective tissue supports, binds, and protects other tissues (e.g., bone, blood, fat). Nervous tissue is found in the brain, spinal cord, and nerves; connective tissue is

found throughout the body.

(f) Epidermal and ground tissue

Answer: Epidermal tissue is the outer protective layer of plants (epidermis). Ground tissue makes up the bulk of the plant and is involved in photosynthesis, storage, and support (parenchyma, collenchyma, sclerenchyma).

(g) Root and shoot system

Answer: The root system is underground and absorbs water and minerals, anchors the plant, and stores food. The shoot system is above ground and includes stems, leaves, and flowers; it is involved in photosynthesis, transport, and reproduction.

(h) Vegetative and reproductive part

Answer: Vegetative parts are involved in growth and nutrition (roots, stems, leaves). Reproductive parts are involved in reproduction (flowers, fruits, seeds).

2. How different tissues form stomach?

Answer: The stomach is an organ formed by four main types of tissues:

Epithelial Tissue: Lines the inner surface of the stomach, secretes mucus, hydrochloric acid, and digestive enzymes. Muscular Tissue: Smooth muscle layers (circular, longitudinal, oblique) churn and mix food. Connective Tissue: Supports and binds the other tissues (e.g., blood vessels, nerves).

Nervous Tissue: Controls muscle contraction and secretion. These tissues work together to perform the stomach's function of digestion.

3. Why respiratory and cardiovascular systems work together?

Answer: The respiratory and cardiovascular systems work together to deliver oxygen to the body and remove carbon dioxide. The respiratory system brings oxygen into the lungs and expels carbon dioxide. The cardiovascular system transports oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. Without this cooperation, cells would not receive oxygen or get rid of waste gases.

4. How temperature is regulated in our body?

Answer: Body temperature is regulated by the hypothalamus in the brain. It receives signals from thermoreceptors in the skin and blood. When body temperature rises, the hypothalamus triggers vasodilation and sweating to cool the body. When body temperature falls, it triggers vasoconstriction, shivering, and increased metabolic rate to generate heat. This is an example of negative feedback.

1. Justify how the cells of leaf have a variety of specialized structure and function.

Answer: Leaf cells are highly specialized for photosynthesis and gas exchange. Different cell types have specific structures and functions that enable the leaf to perform its role efficiently.

1. Epidermal Cells:

Structure: Flattened, tightly packed, covered by a waxy cuticle. Function: Protection, reduce water loss.

2. Guard Cells:

Structure: Bean-shaped, contain chloroplasts, thick inner walls. Function: Regulate stomatal opening and closing for gas exchange and transpiration.

3. Palisade Mesophyll Cells:

Structure: Columnar, tightly packed, many chloroplasts. Function: Main site of photosynthesis.

4. Spongy Mesophyll Cells:

Structure: Irregular, loosely packed, few chloroplasts, large air spaces. Function: Gas exchange, some photosynthesis.

5. Xylem Vessels:

Structure: Dead, hollow tubes, lignified walls. Function: Transport water and minerals.

6. Phloem Sieve Tubes:

Structure: Living cells, sieve plates, companion cells. Function: Transport sugars.

In summary, leaf cells are specialized to maximize photosynthesis, gas exchange, and transport, demonstrating the relationship between structure and function.

2. State the relationship between structure and function of root hairs, xylem vessels and red blood cell.

Answer: The structure of a cell is always adapted to its specific function.

1. Root Hair Cell:

Structure: Long, thin extension; large vacuole; thin cell wall. Function: Absorption of water and minerals. Relationship: The long extension increases surface area for absorption. The large vacuole creates a low water potential, drawing water in by osmosis.

2. Xylem Vessel:

Structure: Dead, hollow tube; lignified walls; no end walls. Function: Transport of water and minerals; support. Relationship: The hollow lumen provides a low-resistance pathway for water. Lignin provides strength and prevents collapse under tension.

3. Red Blood Cell:

Structure: Biconcave disc; no nucleus; contains hemoglobin. Function: Transport of oxygen. Relationship: The biconcave shape increases surface area for gas exchange. The absence of a nucleus provides more space for hemoglobin. Hemoglobin binds oxygen reversibly.

In summary, the structure of each cell type is highly adapted to its specific function.

3. Write a detailed note on animal tissues.

Answer: Animal tissues are groups of cells with similar structure and function. There are four main types of animal tissues:

1. Epithelial Tissue:

Structure: Tightly packed cells, covering body surfaces, lining cavities, and forming glands. Function: Protection, absorption, secretion, and filtration. Examples: Skin, lining of the digestive tract, kidney tubules.

2. Connective Tissue:

Structure: Cells scattered in an extracellular matrix. Function: Support, binding, protection, and transport. Examples: Bone, cartilage, blood, adipose tissue.

3. Muscular Tissue:

Structure: Elongated cells containing contractile proteins (actin and myosin). Function: Movement. Types: Skeletal (voluntary), smooth (involuntary), cardiac (involuntary).

4. Nervous Tissue:

Structure: Neurons and glial cells. Function: Transmit electrical impulses. Examples: Brain, spinal cord, nerves.

In summary, animal tissues are specialized to perform a wide range of functions necessary for the survival of the organism.

4. Give an account of levels of biological organization.

Answer: Biological organization is the hierarchy of complex biological structures and systems that define life. The levels, from smallest to largest, are:

1. Atomic Level: Atoms (e.g., C, H, O, N) are the building blocks of matter.

2. Molecular Level: Molecules (e.g., water, proteins, DNA) are formed by atoms.

3. Organelle Level: Organelles (e.g., mitochondria, ribosomes) are specialized structures within cells.

4. Cellular Level: Cells are the basic unit of life.

5. Tissue Level: Tissues are groups of similar cells performing a specific function.

6. Organ Level: Organs are groups of different tissues working together.

7. Organ System Level: Organ systems are groups of organs working together.

8. Organism Level: An organism is a complete living being.

9. Population Level: A population is a group of organisms of the same species.

10. Community Level: A community is a group of populations living in the same area.

11. Ecosystem Level: An ecosystem is a community and its physical environment.

12. Biosphere Level: The biosphere is the global sum of all ecosystems.

In summary, life is organized into a hierarchy of levels, each building upon the previous one.

5. Explain the functions of different organ system of human.

Answer: The human body is made of several organ systems, each with specific functions:

1. Integumentary System: Protection, temperature regulation, vitamin D synthesis.

2. Skeletal System: Support, protection, movement, blood cell production.

3. Muscular System: Movement, posture, heat production.

4. Nervous System: Control and coordination, sensation, thought.

5. Endocrine System: Hormone production, regulation of metabolism, growth, reproduction.

6. Cardiovascular System: Transport of blood, oxygen, nutrients, waste.

7. Respiratory System: Gas exchange (oxygen in, carbon dioxide out).

8. Digestive System: Breakdown and absorption of nutrients.

9. Urinary System: Removal of waste, water and electrolyte balance.

10. Reproductive System: Production of gametes, reproduction.

11. Lymphatic/Immune System: Defense against pathogens, fluid balance.

In summary, each organ system performs a specific function, and together they maintain homeostasis.

6. How different organ systems o humans work together to maintain homeostasis?

Answer: Homeostasis is maintained by the coordinated action of multiple organ systems.

Nervous and Endocrine Systems: Act as control centers, detecting changes and sending signals to effectors. Cardiovascular and Respiratory Systems: Work together to deliver oxygen and remove carbon dioxide. Digestive and Circulatory Systems: Work together to absorb and distribute nutrients. Urinary System: Regulates water and electrolyte balance, removes waste. Integumentary System: Regulates body temperature. Muscular and Skeletal Systems: Enable movement and heat production.

Examples:

Blood Glucose: Regulated by insulin and glucagon (endocrine), liver (digestive), and muscle cells. Body Temperature: Regulated by hypothalamus (nervous), skin (integumentary), and muscles (muscular). Water Balance: Regulated by kidneys (urinary) and ADH (endocrine).

In summary, homeostasis is a complex, integrated process requiring the cooperation of all organ systems.

7. Cells and tissues are adapted to perform their function in the best way. Explain this statement by using example of leaf.

Answer: The statement "cells and tissues are adapted to perform their function in the best way" is well illustrated by the leaf.

1. Palisade Mesophyll Cells:

Adaptation: Columnar shape, many chloroplasts, located near the upper surface. Function: Maximize light absorption for photosynthesis.

2. Spongy Mesophyll Cells:

Adaptation: Irregular shape, large air spaces. Function: Facilitate gas exchange (CO₂ in, O₂ out).

3. Guard Cells:

Adaptation: Bean-shaped, thick inner walls, contain chloroplasts. Function: Regulate stomatal opening and closing to control gas exchange and water loss.

4. Xylem Vessels:

Adaptation: Dead, hollow tubes, lignified walls. Function: Transport water and minerals; provide support.

5. Phloem Sieve Tubes:

Adaptation: Living cells, sieve plates, companion cells.

Function: Transport sugars.

6. Epidermal Cells:

Adaptation: Flattened, tightly packed, covered by a waxy cuticle. Function: Protection, reduce water loss.

In summary, the leaf is a highly organized organ where each cell and tissue type is adapted to perform its specific function efficiently.