ParhaiKrlo
9th Class Biology · Punjab Board · Chapter 5

Chapter 5: Tissues, Organs and Organ SystemsLong Questions with Answers

13 long (comprehensive) questions of 9th Class Biology Chapter 5, Tissues, Organs and Organ Systems, answered in full with headings, diagrams and tables, including important board-paper questions beyond the book. Punjab Board new syllabus.

StartFull chapter guideMCQsShort Questions
Chapter 5· Tissues, Organs and Organ Systems

Long Questions with Answers

Long answers, explained in full with headings. Learn the structure: definition, explanation, diagram or table, example.

Set A: Textbook comprehensive questions 10 questions

The long questions at the end of the chapter in your book.

Long Q 5.1

Explain the levels of organization in a multicellular organism. How does each level contribute to the overall function of an organism?

Answer
AtomC, H, OC, H, OMoleculewaterglucoseOrganellemitochondrionchloroplastCellmuscle cellmesophyll cellTissuecardiac musclemesophyllOrganheartleafOrgansystemcirculatoryshoot systemOrganismhumantreesimplestmost complexrow 1: animal example · row 2: plant exampleEach level is built from the one before it; new (emergent) properties appear at every step
Levels of organization.
  1. Atom: smallest unit keeping the property of an element (C, H, O).
  2. Molecule: atoms combined (water, protein, nucleic acid).
  3. Organelle: specialized subcellular part (mitochondria for respiration, ribosomes for protein synthesis).
  4. Cell: organelles assembled; smallest unit of life; can reproduce.
  5. Tissue: similar cells for a specific function (epithelial, muscle; epidermal, vascular).
  6. Organ: related tissues working together (heart, lungs; leaves, roots).
  7. Organ system: organs for related functions (circulatory, digestive; root, shoot).
  8. Organism: independent living entity (humans, trees).

Contribution

Each level builds on the one below and adds emergent properties: cells divide and make proteins; tissues contract; the heart pumps; the digestive system digests; the organism thinks and responds. The organism functions only when all levels work together.

Long Q 5.2

What is a tissue level? Explain plant and animal tissues.

Answer
Definition
Tissue

A group of similar cells that work together to perform one or more specific functions.

Animal tissues

  • Epithelial tissue: covers body surfaces and lines cavities (skin, stomach lining).
  • Muscle tissue: enables movement (cardiac muscle in the heart; smooth muscle in the stomach).
  • Connective tissue: support; contains blood vessels and nerves.

Plant tissues

  • Epidermal tissue: protects underlying parts (leaf epidermis with cuticle and stomata).
  • Mesophyll tissue: photosynthesis (palisade and spongy).
  • Vascular tissue: xylem (water, minerals) and phloem (food); a complex tissue.
CuticleUpper epidermisPalisade mesophyllSpongy mesophyllAir spaceLower epidermisXylemPhloemGuard cellStoma
Plant tissues in a leaf.
Long Q 5.3

Describe the tissue composition of the stomach. How does each tissue contribute to the digestive function of the stomach?

Answer
inside (lumen)outsideEpithelial tissuemucus, HCl, pepsinogenConnective tissueblood vessels, nerves, lymphaticsMuscle: longitudinal / circular / obliquechurns food with gastric juiceOuter connective tissueencircles and supports
Tissues of the stomach.

The stomach partly digests proteins and stores food. Its wall has four tissue layers:

1. Epithelial tissue

Inner glandular wall; secretes mucus (protects the wall from acid) and gastric juice: pepsinogen for protein digestion and HCl to activate it to pepsin.

2. Connective tissue

Beneath the epithelium; structural support; carries blood vessels, nerves and lymphatics (supply and control).

3. Muscle tissue

Outer longitudinal, middle circular and inner oblique smooth muscle; contract and relax to mix food with gastric juice.

4. Outer connective tissue

Encircles and supports the stomach.

Long Q 5.4

Describe the tissue composition of the leaf. How does each tissue contribute to the function of the leaf?

Answer
CuticleUpper epidermisPalisade mesophyllSpongy mesophyllAir spaceLower epidermisXylemPhloemGuard cellStoma
Tissues of a leaf.

Epidermal tissue

Upper epidermis with waxy cuticle reduces water loss and protects. Lower epidermis has guard cells and stomata that control gas exchange and loss of water vapour.

Mesophyll tissue

Cells rich in chloroplasts; site of photosynthesis. Palisade mesophyll: tightly packed elongated cells beneath the upper epidermis. Spongy mesophyll: loose cells with air spaces for diffusion of gases.

Vascular tissue

In midrib and veins; xylem brings water and minerals from the stem; phloem carries sugars to the stem.

Together they let the leaf make food (photosynthesis) and lose water vapour (transpiration).

Long Q 5.5

How do the organ systems come together to form the human body?

Answer
SkeletalDigestiveRespiratoryMuscularNervousCirculatorybones, jointsstomach, intestineswindpipe, lungsmuscles, tendonsbrain, cord, nervesheart, vessels
Human organ systems.
SystemOrgansFunction
Skeletalbones, cartilages, tendonssupport, protection, movement framework, minerals, blood cells
Muscularskeletal musclesmovement and locomotion
Digestivemouth, oesophagus, stomach, intestinesdigestion and absorption
Respiratorylungs, trachea, bronchigas exchange
Circulatoryheart, vessels, bloodtransport
Nervousbrain, spinal cord, nervescontrol and coordination

The systems are linked: digestive and respiratory systems take in food and oxygen, the circulatory system carries them to cells, the nervous system coordinates all, and their interaction gives emergent properties like thinking and responding to the environment.

Long Q 5.6

Describe the role of the digestive system and the excretory system in homeostasis.

Answer

Digestive system

It works for proper distribution of nutrients to cells for energy, growth and repair. The pancreas releases insulin when blood glucose rises (e.g. after juice), lowering it to normal; the liver stores glucose. So blood sugar stays stable.

Excretory (urinary) system

It eliminates waste materials from the body and regulates water and salt balance in body tissues; in this way it maintains blood volume, blood pressure and pH levels. The kidneys filter wastes from blood and produce urine.

Long Q 5.7

Explain the functions of various plant organs.

Answer
  • Roots: anchor the plant, absorb water and essential minerals, store nutrients.
  • Stems: support leaves, flowers and fruits; xylem and phloem move water, minerals and nutrients.
  • Leaves: primary sites of photosynthesis and transpiration.
  • Flowers: reproductive part; sexual reproduction (pollination, seeds and fruits).
SHOOT SYSTEMstem, leaves, flowers, fruitssupport, photosynthesis,reproductionROOT SYSTEManchors the plant, absorbswater and minerals, stores foodFlower: reproductionLeaf: photosynthesisStem: support, transportRootsground
Plant organs and systems.
Long Q 5.8

Describe the structure and function of the plant root system.

Answer

Structure

The root system consists of roots, usually underground: a main root with branches and fine root hairs (extensions of epidermal cells) that increase surface area; vascular tissue (xylem and phloem) runs through them.

Functions

  • Anchors the plant in the soil.
  • Absorbs water and salts (minerals) from the soil.
  • Stores food in some plants (carrot, radish).
  • Passes water up to the shoot through xylem.
SHOOT SYSTEMstem, leaves, flowers, fruitssupport, photosynthesis,reproductionROOT SYSTEManchors the plant, absorbswater and minerals, stores foodFlower: reproductionLeaf: photosynthesisStem: support, transportRootsground
Root and shoot systems.
Long Q 5.9

Define homeostasis and explain its importance. Discuss how different organ systems work together to maintain homeostasis.

Answer
Definition
Homeostasis

The ability of an organism to maintain a stable internal environment despite changes in the external environment.

Importance

Cells work properly only when temperature, pH, salts, glucose and oxygen stay in the normal range. Examples: sweating and shivering keep 37 °C; insulin lowers blood sugar; faster breathing during exercise.

Normal bodytemperature 37 °Crises above 37 °Cfalls below 37 °CBrain centre → sweatglands: sweat evaporates,heat is lostfalls to 37 °CBrain centre → muscles:shivering generatesheatrises to 37 °C
Temperature control.

Systems working together

  • Nervous and endocrine: regulate heart rate, respiration, metabolism.
  • Respiratory: oxygen in, CO₂ out.
  • Cardiovascular: temperature, pH, delivery to cells.
  • Digestive: nutrients.
  • Muscular and skeletal: posture and movement.
  • Urinary: wastes, water and salts, blood pressure.
  • Integumentary: barrier, sweating.
Long Q 5.10

Describe how the respiratory and circulatory systems work together to maintain homeostasis of oxygen and carbon dioxide levels in the body.

Answer

Respiratory system

The lungs, trachea and bronchi exchange oxygen and carbon dioxide between the body and the environment: oxygen enters the blood and CO₂ leaves it in the lungs.

Circulatory system

The heart pumps blood through vessels; blood carries oxygen from the lungs to every cell and brings CO₂ from cells back to the lungs.

Working together

During hard exercise, muscles need more oxygen and produce more CO₂; the nervous system increases the breathing rate and heartbeat, so more oxygen is supplied and extra CO₂ is removed. When activity stops, both rates fall. In this way O₂ and CO₂ (and blood pH) stay in the normal range.

Set B: More important long questions 3 questions

Long questions often set in board papers from this chapter, answered in the same full style.

Imp. LQ 1

What are emergent properties? Explain them with examples at each level of organization.

Answer

Components at each level interact and create new functions called emergent properties: abilities present at a higher level that are not possible from individual components. Aristotle: "The whole is greater than the sum of its parts."

  • Organelles → cell: cell division, protein synthesis, energy production.
  • Cells → tissue: muscle tissue contracts and generates force.
  • Tissues → organ: the heart pumps blood.
  • Organs → organ system: the digestive system digests and absorbs food.
  • Organ systems → organism: consciousness, thinking, responding to the environment.
Imp. LQ 2

Write a note on the human organs and their functions.

Answer
OrganFunction
Heartpumps blood
Lungsgas exchange
Braincontrol, thinking, decisions
Liverfilters blood, bile, stores glucose
Kidneysfilter wastes, urine
Stomachbreaks down food
Intestinesdigestion and absorption
Pancreasenzymes; insulin and glucagon
Imp. LQ 3

Describe the homeostasis of body temperature.

Answer
Normal bodytemperature 37 °Crises above 37 °Cfalls below 37 °CBrain centre → sweatglands: sweat evaporates,heat is lostfalls to 37 °CBrain centre → muscles:shivering generatesheatrises to 37 °C
Body temperature around 37 °C.

When temperature rises

During hard work muscles produce heat; the temperature regulating centre in the brain sends a message to sweat glands; sweat evaporates and heat is lost; temperature falls to 37 °C.

When temperature falls

The centre sends a message to muscles; shivering generates heat; temperature rises to 37 °C.

The skin (integumentary system) and blood flow (cardiovascular system) also help.

End of Chapter 5 Long QuestionsNext: Chapter 5 MCQs →

The rest of Chapter 5

5Chapter
Full guide: Tissues, Organs and Organ Systems (notes, diagrams, all questions, self-test)
›

Long Questions from other Biology chapters

1Chapter
The Science of Biology Long Questions
›
2Chapter
Biodiversity Long Questions
›
3Chapter
The Cell Long Questions
›
4Chapter
Cell Cycle Long Questions
›
6Chapter
Biomolecules Long Questions
›
‹ Chapter 5 full guide · All 9th Class Biology chapters · Matric home