GK: Class 12 General Q&A · Page 15
3,658 free answers on GK (General) for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
Why are tissues important?
Tissues are important because they enable complex multicellular organisms to function efficiently through cellular specialization and division of labor. This organizational level makes possible the sophisticated capabilities distinguishing complex life forms from simple organisms. Tissues provide several critical advantages. Specialization allows specific cell groups to become highly efficient at particular tasks rather than every cell performing all functions poorly. Muscle tissue ex
- GeneralClass 12All
What is plant tissue?
Plant tissue is organized groups of plant cells working together to perform specific functions necessary for plant growth, development, and survival. Plant tissues are classified as either meristematic (capable of continuous cell division) or permanent (differentiated cells with specialized functions). Meristematic tissues contain undifferentiated cells that actively divide to produce new cells, enabling plant growth. Apical meristems at root and shoot tips facilitate lengthwise growt
- GeneralClass 12All
What diseases affect tissues?
Numerous diseases affect tissues, ranging from inflammatory conditions and degenerative disorders to cancers and infections. Virtually every medical condition involves tissue-level changes, though some specifically target particular tissue types. Epithelial tissue diseases include cancers (lung, skin, breast, colorectal carcinomas), inflammatory conditions (dermatitis, gastritis), and functional disorders (irritable bowel syndrome affecting intestinal epithelium). Connective tissue di
- GeneralClass 12All
What is body tissue?
Body tissue refers to any of the four main tissue types found in the human body: epithelial, connective, muscle, and nervous tissue. These tissues construct all anatomical structures and enable all physiological functions necessary for life. Body tissues represent the organized cellular level between individual cells and complete organs. Each tissue type has distinct characteristics and functions. Epithelial tissue forms protective coverings on body surfaces, lines internal cavities a
- GeneralClass 12All
What disease attacks its own tissue?
Autoimmune diseases attack the body's own tissues, occurring when the immune system mistakenly identifies healthy tissues as foreign threats and launches attacks against them. These conditions affect approximately 5-8% of the population and can target virtually any body tissue. Common autoimmune diseases include rheumatoid arthritis (attacking joint tissues), type 1 diabetes (destroying insulin-producing pancreatic cells), multiple sclerosis (damaging nervous tissue's protective myeli
- GeneralClass 12All
What causes damage to body tissues?
Damage to body tissues occurs through mechanical injury, chemical exposure, biological agents, thermal extremes, radiation, nutritional deficiencies, immune dysfunction, and inadequate blood supply. Each mechanism harms tissues through distinct pathways. Mechanical injury includes cuts, bruises, fractures, and repetitive stress, directly disrupting tissue structure through external forces. Chemical damage results from acids, bases, solvents, and toxins that denature proteins or disrup
- GeneralClass 12All
What is the most common tissue in the body?
Connective tissue is the most common tissue in the body, found throughout virtually every body region and serving diverse functions from structural support to immune defense. It comprises approximately 45-50% of total body mass. Connective tissue's abundance reflects its diverse forms and functions. It includes bone (providing rigid skeletal support), cartilage (cushioning joints), adipose tissue (storing energy), blood (transporting materials), lymphatic tissue (immune function), ten
- GeneralClass 12All
What causes tissue damage?
Tissue damage results from various factors including physical trauma, infections, toxins, oxygen deprivation, immune system attacks, and aging. Understanding these causes helps prevent injury and guide appropriate treatment. Physical trauma—from falls, accidents, sports injuries, or surgery—directly disrupts tissue structure. Blunt force crushes cells, while sharp objects sever tissues. Repetitive stress gradually damages tissues, causing conditions like tendinitis or stre
- GeneralClass 12All
Who discovered tissue?
The formal recognition and naming of tissue is credited to Marie François Xavier Bichat, a French anatomist and pathologist who, in the late 1700s, identified 21 different tissue types in the human body without using a microscope. His systematic classification laid the foundation for modern histology. Bichat's groundbreaking work, published in his 1801 treatise "Anatomie Générale," revolutionized medical understanding by shifting focus from organs to tissues. He r
- GeneralClass 12All
What best defines tissue?
Tissue is best defined as a group of structurally similar cells and their intercellular matrix that work together to perform specialized functions. This definition captures the essential characteristics that distinguish tissue from isolated cells or complete organs. The key elements of this definition deserve emphasis. "Structurally similar cells" indicates that tissue cells share common characteristics—muscle tissue contains muscle cells, nervous tissue contains neurons and sup
- GeneralClass 12All
What is the simple layer of tissue?
A simple layer of tissue refers to simple epithelium, which consists of a single layer of epithelial cells. This tissue structure is found where thinness facilitates specific functions like absorption, secretion, or filtration. Simple epithelium exists in several forms based on cell shape. Simple squamous epithelium consists of flat, scale-like cells forming thin membranes ideal for diffusion—it lines blood vessels (where it's called endothelium), allowing oxygen and nutrients t
- GeneralClass 12All
What is the smallest unit of tissue?
The smallest unit of tissue is the cell. This fundamental biological principle recognizes that while tissues comprise many cells working together, each individual cell represents the indivisible functional unit of that tissue. Understanding cells as tissue's smallest unit has profound implications for biology and medicine. When examining tissue under a microscope, pathologists identify disease by observing cellular abnormalities—cancer diagnosis relies on detecting cells with al
- GeneralClass 12All
What is organ tissue called?
Organ tissue is simply called tissue. Organs are structures composed of multiple tissue types working together to perform specific functions, but the tissues themselves retain their standard names: epithelial, connective, muscle, and nervous tissue. The confusion sometimes arises because people wonder if tissues within organs have special names, but they don't—a heart contains cardiac muscle tissue (not "heart tissue"), connective tissue, epithelial tissue lining blood vessels,
- GeneralClass 12All
What is a simple tissue called?
Simple tissue is called a tissue composed of only one type of cell. This term primarily applies to plant biology, where simple tissues include parenchyma, collenchyma, and sclerenchyma, each performing specific functions. Parenchyma consists of living cells with thin walls and serves multiple roles including photosynthesis, storage, and tissue repair. You find parenchyma in the fleshy parts of fruits, the middle layers of leaves, and throughout plant stems. Collenchyma contains living
- GeneralClass 12All
Why is tissue important?
Tissue is important because it represents the organizational level where cellular specialization translates into complex body functions. Without tissues, multicellular life as we know it could not exist. The importance of tissue extends across multiple dimensions. Physiologically, tissues enable specialized functions that isolated cells cannot perform—a single muscle cell twitches weakly, but muscle tissue lifts heavy objects. Tissues also facilitate efficient resource allocatio
- GeneralClass 12All
What are tissues used for?
Tissues are used for maintaining body structure, enabling movement, protecting against harm, transporting materials, coordinating body systems, and supporting all life processes. Their applications extend beyond natural functions to medical and research uses. In the body, epithelial tissues form protective barriers on skin and organ surfaces while enabling selective absorption and secretion. Connective tissues provide structural frameworks (bones), cushion organs (adipose tissue), fig
- GeneralClass 12All
What are common tissue diseases?
Common tissue diseases include connective tissue disorders, muscular dystrophies, epithelial cancers, and neurodegenerative conditions. These affect millions worldwide and range from manageable chronic conditions to life-threatening illnesses. Connective tissue diseases like rheumatoid arthritis, lupus, and scleroderma occur when the immune system mistakenly attacks the body's own connective tissues, causing inflammation, pain, and organ damage. Osteoarthritis represents another commo
- GeneralClass 12All
What is the function of tissue?
The function of tissue is to perform specialized tasks that maintain organism health and survival. Each tissue type has evolved specific capabilities that individual cells alone cannot achieve, enabling complex life processes. Epithelial tissue functions as a protective barrier, guarding against pathogens, physical damage, and water loss while also facilitating absorption in the intestines and secretion in glands. Connective tissue provides structural support (bone and cartilage), sto
- GeneralClass 12All
What is a cell organ?
A cell organ, more properly called an organelle, is a specialized structure within a cell that performs a specific function, much like how organs function within the body. These structures are essential for cellular survival and activity. The term "organelle" literally means "little organ," reflecting the functional parallel between these cellular structures and body organs. Major organelles include the nucleus (containing genetic material and controlling cell activities), mitochondri
- GeneralClass 12All
What is the basic unit of tissue?
The basic unit of tissue is the cell. Tissues are formed when multiple cells of similar type and function organize together, making the cell the fundamental building block from which all tissues are constructed. This concept reflects the cell theory, one of biology's foundational principles, which states that all living organisms are composed of cells, and all cells arise from pre-existing cells. When examining any tissue under a microscope, you observe numerous individual cells&mdash