A cell is the fundamental structural and functional unit of all living organisms, a concept established as the cell theory. This theory posits that all living things are composed of cells, that the cell is the basic unit of life, and that all new cells arise from pre-existing cells. Cells exhibit a vast diversity in size, shape, and function, which is directly related to the specific roles they perform within an organism. Some organisms, like bacteria, are unicellular, consisting of just a single cell capable of performing all life processes. In contrast, complex plants and animals are multicellular, composed of billions of specialized cells that work in a coordinated manner to sustain the entire being.
The intricate internal structure of a cell, known as its protoplasm, is divided into the nucleus and the cytoplasm, all enclosed by a plasma membrane. The nucleus acts as the control centre, housing the genetic material DNA which directs all cellular activities. Surrounding the nucleus, the cytoplasm is a jelly-like matrix containing various organelles, each with a distinct function. Other vital structures are the endoplasmic reticulum for transport, Golgi bodies for packaging, and lysosomes for waste breakdown.
A key distinction exists between primitive prokaryotic cells, which lack a defined nucleus and are found in bacteria, and the more advanced eukaryotic cells that possess a true nucleus and membrane-bound organelles, which make up plants, animals, and fungi. Furthermore, plant and animal cells themselves differ significantly. Plant cells are characterized by a rigid cell wall that provides structural support and a large central vacuole for storage. They also contain plastids like chloroplasts. Animal cells lack these features, giving them a more flexible and irregular shape, and they may possess smaller, numerous vacuoles. This cellular organization is what enables all the life processes to occur efficiently.
- Multiple choice type
Question 1.
Choose the most appropriate option in the following statement.
Palaeontology is the study of ____________
- embryos
- Blood
- Blood
- Fossils
Question 2.
Choose the most appropriate option in the following statement.
Clones of animals are being produced through the practice of ___________.
- genetics
- ecology
- Embryology
- Biotechnology
- Very short answer type
Question 1.
1. Name the following branches of biology. Application of biological process in technology.
2. Name the following branches of biology. Science of growing fruits and vegetables.
3. Name the following branches of biology. Study of prehistoric forms of life.
4. Name the following branches of biology. Study of causes of immunity (resistance to or defence against disease).
5. Name the following branches of biology. Study of fishes.
Ans:
- Application of biological process in technology: Biotechnology
- Science of growing fruits and vegetables: Horticulture (or sometimes specifically Olericulture for vegetables and Pomology for fruits)
- Study of prehistoric forms of life: Palaeontology
- Study of causes of immunity (resistance to or defence against disease): Immunology
- Study of fishes: Ichthyology
Question 2.
1. Fill in the blanks : Bioengineering deals with making artificial ________.
2. Fill in the blanks : _____ is the entire DNA sequence of an organ.
3. Fill in the blanks : Silk is produced by rearing ________
4. Fill in the blanks : Evolutions deal with the study of _________ and ____________ of organs.
5. Fill in the blanks : Organisms which draw food from the host body are called __________.
6. Fill in the blanks : Animals which give birth to young ones are known as _________.
7. Fill in the blanks : ______ is called the father of medicine.
Ans:
- Bioengineering deals with making artificial organs (or prosthetics/medical devices).
- The Genome is the entire DNA sequence of an organism (or a cell, which is contained in every cell of an organ).
- Silk is produced by rearing silkworms (specifically, the larvae of the silk moth).
- Evolution deals with the study of origin and descent (or development/modification) of organisms.
- Organisms which draw food from the host body are called parasites.
- Animals which give birth to young ones are known as viviparous animals.
- Hippocrates is called the father of medicine.
Question 3.
Match the branches of biology in column A with the respective areas of study in column B.
| Column A | Column B |
| Ichthyology | Viruses |
| Ornithology | Fishes |
| Ecology | Birds |
| Virology | Cells |
| Herpetology | Diseases |
| Paleontology | Fossils |
| Cytology | Snakes |
| Pathology | Environment |
Ans:
| Column A (Branch of Biology) | Column B (Area of Study) |
| Ichthyology | Fishes |
| Ornithology | Birds |
| Ecology | Environment |
| Virology | Viruses |
| Herpetology | Snakes (and other reptiles and amphibians) |
| Paleontology | Fossils |
| Cytology | Cells |
| Pathology | Diseases |
Question 4.
Name any two borderline sciences which are connected with biology.
Ans:
Two borderline sciences (or interdisciplinary fields) which are connected with biology are:
- Biochemistry
- This field combines Biology and Chemistry.
- It focuses on the chemical processes and substances that occur within living organisms, such as the structure and function of proteins, nucleic acids, carbohydrates, and lipids.
- Biophysics
- This field combines Biology and Physics.
- It applies the theories and methods traditionally used in physics to study biological systems and problems, such as understanding the mechanical forces in cell movement or the electrical properties of neurons.
Other Borderline Sciences Include:
- Biotechnology (Biology and Technology/Engineering)
- Bioinformatics (Biology and Computer Science/Statistics)
- Biomathematics/Biostatistics (Biology and Mathematics/Statistics)
Question 5.
Name the respective sub-division of biology which deal with the study of insects, birds, fungi and heredity.
Ans:
The respective sub-divisions of biology that deal with the study of insects, birds, fungi, and heredity are:
- Insects: Entomology
- Birds: Ornithology
- Fungi: Mycology
- Heredity: Genetics
Question 6.
Name some professions other than medicine which require basic knowledge of biology.
Ans:
A basic knowledge of biology is essential for numerous professions outside of direct medical practice. These careers apply biological principles to various fields, including environment, technology, and agriculture.
Scientific and Research Professions
These roles involve direct scientific investigation and analysis of living systems:
- Microbiologist: Studies microorganisms like bacteria, viruses, and fungi, which is vital for food safety, environmental cleanup, and drug production.
- Geneticist / Genetic Counselor: Studies heredity, genes, and variations in organisms. Genetic counselors use this knowledge to assess disease risk for individuals and families.
- Biotechnologist / Biomedical Scientist: Applies biological concepts (like genetic engineering and cell culture) to develop new technologies, drugs, vaccines, and diagnostic tools.
- Forensic Scientist: Uses biological evidence (like DNA, blood, and fibers) in criminal or civil investigations.
- Pharmacologist: Researches how drugs interact with biological systems to develop new medications and ensure safety.
Environmental and Agricultural Professions
These professions focus on living organisms and their interaction with the environment:
- Environmental Scientist / Ecologist: Studies the relationships between organisms and their environments, often working to protect natural resources, manage ecosystems, and address pollution.
- Zoologist / Marine Biologist: Studies animal behavior, physiology, genetics, and ecology, often for conservation or research purposes.
- Botanist / Plant Breeder: Studies plant life, growth, and development, often working to improve crop yields, disease resistance, or develop new plant-based products.
- Soil Scientist: Studies the biological, chemical, and physical properties of soil, which is crucial for agriculture and environmental management.
Allied and Technical Professions
These fields apply biological knowledge in supportive or technical capacities:
- Clinical Laboratory Scientist (Medical Technologist): Performs complex tests on bodily fluids and tissues to help diagnose diseases.
- Physical Therapist / Occupational Therapist: Works with the human body’s anatomy and physiology to help patients recover from injuries or improve motor skills.
- Food Scientist / Clinical Nutritionist: Applies biology, chemistry, and nutrition knowledge to ensure food safety, improve quality, and evaluate dietary needs for health and wellness.
- Science Teacher / Professor: Instructs students in biology, requiring a deep foundational understanding of the subject matter.
- Short answer type
Question 1.
What is Biology? Name and define its three major branches.
Ans:
What is Biology?
Biology is the natural science that studies life and living organisms, including their physical structure, chemical processes, molecular interactions, physiological mechanisms, development, evolution, and their distribution and interaction with the environment.
The term “Biology” comes from the Greek words bios (life) and logia (study of).
Three Major Branches of Biology
While biology is vast and has countless sub-disciplines, it is conventionally divided into three broad, major branches based on the type of organism studied:
1. Botany
- Definition: Botany is the branch of biology concerned with the study of plants, including their structure, properties, and biochemical processes. It also includes the study of plant classification, diseases, and their interrelationships with the environment.
2. Zoology
- Definition: Zoology is the branch of biology dedicated to the study of animals. This includes the investigation of animal anatomy, physiology, genetics, behavior (ethology), classification, and ecology.
3. Microbiology
- Definition: Microbiology is the branch of biology that deals with the study of microorganisms (microbes), which are typically single-celled or cell-cluster organisms too small to be seen with the naked eye. This includes the study of bacteria, viruses, fungi, algae, and protozoa.
Question 2.
How does biology help us in leading a healthier life?
Ans:
Biology provides the foundational knowledge necessary for leading a healthier life by explaining the workings of the human body, the causes of diseases, and the principles of nutrition and wellness.
Here are three key ways biology helps us lead healthier lives:
- Understanding Disease and Immunity (Medicine):
- Biology, through disciplines like Pathology and Immunology, identifies the causes of diseases (bacteria, viruses, genetic defects) and explains how the immune system defends the body. This knowledge is essential for developing vaccines, antibiotics, and treatments.
- Informing Nutrition and Diet (Physiology):
- Physiology and Biochemistry explain how the body processes food, the functions of vitamins and minerals, and the caloric needs for metabolism. This guides the creation of balanced diets and helps prevent diet-related illnesses like diabetes and heart disease.
- Promoting Hygiene and Prevention (Microbiology):
- Microbiology reveals the presence and behavior of germs. This knowledge drives public health practices, emphasizing hygiene (like handwashing) and sanitation to prevent the spread of infectious diseases.
Question 3.
A farmer and a housewife may have never studied biology, yet both of them know some of its general principles through experience. State any two principles which they know.
Ans:
Even without formal study, both a farmer and a housewife utilize fundamental biological principles learned through practical experience.
Here are two such principles:
- Principle of Growth and Nutrition (Metabolism):
- Farmer: Knows that plants require specific nutrients (from fertilizers/manure) and water at certain stages to grow well and produce a good harvest. They understand that insufficient resources (poor soil, drought) inhibit life processes.
- Housewife: Knows that food spoils quickly due to microbial growth (bacteria, fungi) and uses methods like refrigeration, salting, or drying to slow down or halt these life processes to preserve food.
- Principle of Heredity/Breeding (Genetics):
- Farmer: Selects and saves seeds from the highest-yielding crops or chooses breeding stock (animals) that possess desirable traits (e.g., strong resistance, high milk production) to ensure those traits are passed on to the next generation.
- Housewife: Often has traditional knowledge of which plant varieties or animal breeds produce the best results (best taste, fastest growth, etc.) and knows that “like begets like” when managing their home garden or domestic animals.
Question 4.
1. Distinguish between the following pairs of science : Zoology and Entomology
2. Distinguish between the following pairs of science : Genetics and Eugenics
3. Distinguish between the following pairs of science : Phycology and Mycology
4. Distinguish between the following pairs of science : Space Biology and Exobiology
5. Distinguish between the following pairs of science : Biotechnology and Bioinformatics
6. Distinguish between the following pairs of science :Embryology and Immunology
7. Distinguish between the following pairs of science : Ichthyology and Pisciculture
Ans:
1. Zoology and Entomology
| Feature | Zoology | Entomology |
| Scope | The broad study of all animal life, covering anatomy, physiology, genetics, behavior, ecology, etc., across all animal kingdoms. | A specialized branch of zoology dealing exclusively with the study of insects. |
| Focus | All animals (mammals, birds, reptiles, insects, etc.). | Only insects (the class Insecta). |
2. Genetics and Eugenics
| Feature | Genetics | Eugenics |
| Focus | The scientific study of heredity and variation in living organisms, focusing on genes, DNA, and the transmission of traits. | A social or ethical movement/pseudo-science that advocates for the selective improvement of the human species through controlled breeding and sterilization to eliminate ‘undesirable’ traits. |
| Nature | A purely objective, observational, and experimental science. | A highly controversial and historically unethical social movement with roots in biology. |
3. Phycology and Mycology
| Feature | Phycology | Mycology |
| Organisms | The study of algae (photosynthetic, mostly aquatic, simple eukaryotic organisms). | The study of fungi (heterotrophic, non-photosynthetic eukaryotic organisms like mushrooms, yeasts, and molds). |
| Domain | Typically considered part of Botany (plant sciences). | Considered its own distinct domain, separate from both botany and zoology. |
4. Space Biology and Exobiology
| Feature | Space Biology (Astrobiology/Bioastronautics) | Exobiology (Astrobiology) |
| Focus | Primarily studies the effect of the space environment (microgravity, radiation, isolation) on living organisms, including humans, during space travel. | Primarily studies the possibility of life existing outside of Earth and the search for extraterrestrial life, often focusing on biochemistry and habitability of other planets. |
| Location | Focuses on life in Space (or simulated space environments). | Focuses on life on Other Planets and Celestial Bodies. |
5. Biotechnology and Bioinformatics
| Feature | Biotechnology | Bioinformatics |
| Goal | The application of living organisms and their processes to make or modify useful products or systems (e.g., genetic engineering, brewing, drug development). | The management and analysis of large amounts of biological data (like DNA and protein sequences) using computer science and statistics. |
| Nature | A hands-on, laboratory-based and industrial discipline. | A data-focused, computational and mathematical discipline. |
6. Embryology and Immunology
| Feature | Embryology | Immunology |
| Subject | The study of the formation, growth, and development of an organism from fertilization to the embryonic stage (or birth/hatching). | The study of the immune system—its structure, functions, disorders, and the body’s defense mechanisms against diseases and foreign substances. |
| Focus | Development, differentiation, and morphogenesis. | Defense mechanisms, antibodies, antigens, and resistance to infection. |
7. Ichthyology and Pisciculture
| Feature | Ichthyology | Pisciculture |
| Nature | A branch of zoology dedicated to the scientific study of fishes (including their classification, anatomy, ecology, and evolution). | An applied science/industry concerning the commercial rearing and management of fish in controlled environments (fish farming). |
| Goal | To understand fish life. | To produce fish (usually for food). |
- Long answer type
Do you think Biology can help in further increasing the yield of food? If so, how?
Ans:
How Biology Increases Food Yield
Biological principles and technologies are applied across farming, breeding, and resource management to maximize output:
1. Genetics and Breeding
- High-Yielding Varieties (HYV): Geneticists use knowledge of heredity and plant traits (Genetics) to breed and develop new strains of crops (like rice, wheat, and corn) that produce significantly higher yields per unit area than traditional varieties.
- Disease and Pest Resistance: Plants are genetically engineered or selectively bred to be naturally resistant to specific diseases and pests. This reduces crop loss, minimizes the need for chemical sprays, and increases the harvested yield.
2. Biotechnology and Genetic Engineering
- Genetically Modified Organisms (GMOs): Modern Biotechnology allows scientists to introduce specific genes into crops (e.g., Bt cotton) to enhance traits like tolerance to herbicides or resistance to insect attack, directly saving crops that would otherwise be lost and boosting overall yield.
- Tissue Culture: This technique allows the rapid, large-scale, and clonal propagation of desirable plants (like bananas or potatoes) in sterile lab conditions, ensuring genetically identical, disease-free planting material for farmers.
3. Pest and Soil Management
- Biological Control (Ecology): Knowledge of Ecology helps farmers use natural predators (like ladybugs or parasitic wasps) to control pests instead of relying solely on chemical pesticides. This preserves the crop while protecting the ecosystem.
- Soil Fertility: Microbiology and Soil Science reveal the roles of beneficial microorganisms (e.g., nitrogen-fixing bacteria) in maintaining soil health and fertility, leading to better nutrient uptake by plants and higher productivity.
4. Animal Husbandry (Zoology)
- Improved Livestock: Principles of Zoology and animal genetics are used to develop and maintain breeds of livestock (cattle, poultry, fish) with superior traits, such as increased meat or milk production, better feed conversion efficiency, and faster growth rates.
