1.
Characteristics and Classification of Living Organisms
Characteristics of Living Organisms:
o Movement: Living organisms move, either voluntarily or as a response to
environmental stimuli.
o Respiration: Energy is released from food through cellular respiration.
o Sensitivity: Ability to respond to stimuli in the environment.
o Growth: Organisms grow and develop over time.
o Reproduction: The ability to produce offspring, either sexually or asexually.
o Excretion: Removal of metabolic waste products.
o Nutrition: Organisms require nutrients for energy and growth.
Classification:
Organisms are classified into five kingdoms:
o Monera: Single-celled organisms (e.g., bacteria).
o Protista: Unicellular organisms (e.g., amoeba).
o Fungi: Organisms like molds and yeasts.
o Plantae: Multicellular plants that perform photosynthesis.
o Animalia: Multicellular animals that are typically heterotrophic.
2. Organisation of the Organism
Levels of Organisation:
o Cell: Basic unit of life.
o Tissue: A group of cells working together (e.g., muscle tissue).
o Organ: A structure composed of multiple tissues (e.g., heart).
o Organ system: A group of organs working together (e.g., digestive system).
o Organism: A complete living entity (e.g., human, tree).
3. Movement into and out of Cells
Passive Transport: No energy required.
o Diffusion: Movement of molecules from high to low concentration.
o Osmosis: Movement of water molecules across a semi-permeable membrane.
o Facilitated Diffusion: Movement of molecules through transport proteins in the
membrane.
Active Transport: Requires energy (ATP).
o Molecules move against their concentration gradient via protein pumps (e.g.,
sodium-potassium pump).
4. Biological Molecules
Carbohydrates: Provide energy (e.g., glucose, starch).
Proteins: Composed of amino acids, involved in structure, enzymes, and immune
responses.
Lipids: Provide energy storage and make up cell membranes (e.g., fats, oils).
Nucleic Acids: DNA and RNA, involved in storing and transmitting genetic information.
5. Enzymes
Enzymes: Biological catalysts that speed up chemical reactions.
o Substrate: The molecule that an enzyme acts on.
o Active site: The part of the enzyme where the substrate binds.
o Factors affecting enzyme activity:
Temperature: High temperatures can denature enzymes.
pH: Each enzyme has an optimal pH range.
Substrate concentration: Higher concentrations increase activity up to a
point.
6. Plant Nutrition
Photosynthesis: Process by which plants convert light energy into chemical energy.
o Reactants: Carbon dioxide + Water
o Products: Glucose + Oxygen
o Occurs in the chloroplasts of plant cells.
Mineral Nutrients: Plants require minerals like nitrogen, phosphorus, and potassium for
growth.
7. Human Nutrition
Macronutrients:
o Carbohydrates: Primary energy source.
o Proteins: Used for growth, repair, and enzymes.
o Fats: Provide energy and store energy.
Micronutrients:
o Vitamins: Essential for various biochemical processes (e.g., Vitamin C for
immune function).
o Minerals: Important for body functions (e.g., calcium for bones, iron for blood).
Digestive System: Breaks down food to absorb nutrients (mouth → esophagus →
stomach → small intestine → large intestine).
8. Transport in Plants
Xylem: Transports water and minerals from the roots to the leaves.
Phloem: Transports sugars produced during photosynthesis from the leaves to other parts
of the plant.
9. Transport in Animals
Circulatory System: Transport of gases, nutrients, and waste products.
o Heart: Pumps blood through arteries and veins.
o Arteries: Carry oxygenated blood away from the heart.
o Veins: Carry deoxygenated blood back to the heart.
o Capillaries: Thin-walled vessels where exchange of gases, nutrients, and waste
occurs.
10. Diseases and Immunity
Infectious Diseases: Caused by pathogens like bacteria, viruses, and fungi.
Immune System: Protects the body from pathogens.
o White Blood Cells: Fight infections.
o Antibodies: Proteins produced by the immune system to neutralize pathogens.
o Vaccines: Stimulate immunity by introducing weakened or inactivated pathogens.
11. Gas Exchange in Humans
Respiratory System: Involves the exchange of gases (oxygen and carbon dioxide).
o Lungs: Main organ for gas exchange.
o Alveoli: Small air sacs in the lungs where oxygen enters the blood and carbon
dioxide exits.
o Breathing Process: Inhalation and exhalation.
12. Respiration
Aerobic Respiration: Requires oxygen; produces energy (ATP) from glucose.
o Equation: Glucose + Oxygen → Carbon Dioxide + Water + Energy
Anaerobic Respiration: Occurs without oxygen, producing less energy.
o Equation: Glucose → Lactic Acid + Energy (in humans).
13. Excretion in Humans
Excretory System: Removes waste products from the body.
o Kidneys: Filter blood to remove waste and excess substances, forming urine.
o Ureters: Transport urine from kidneys to the bladder.
o Bladder: Stores urine before excretion.
14. Coordination and Response
Nervous System: Transmits signals for quick responses.
o Neurons: Nerve cells that transmit electrical impulses.
o Central Nervous System (CNS): Brain and spinal cord.
o Peripheral Nervous System (PNS): Nerves that connect the CNS to the body.
Endocrine System: Releases hormones to regulate long-term processes like growth and
metabolism.
o Hormones: Chemical messengers (e.g., insulin, adrenaline).
Questions
1. Characteristics and Classification of Living Organisms
1. What are the seven characteristics of living organisms?
2. How do plants and animals differ in terms of their nutrition?
3. What is the primary method of classification in biology, and what are the five kingdoms of life?
4. Why is the ability to reproduce considered a characteristic of life?
5. Explain the difference between unicellular and multicellular organisms.
2. Organisation of the Organism
1. What is the hierarchy of biological organization from cells to organisms?
2. How do tissues, organs, and organ systems work together to form an organism?
3. Give an example of a tissue and an organ in the human body and explain their functions.
4. What is the difference between an organ and an organ system?
5. Why is the cell considered the basic unit of life?
3. Movement into and out of Cells
1. What is the difference between diffusion and osmosis?
2. How does facilitated diffusion differ from simple diffusion?
3. Define active transport and explain why it requires energy.
4. What would happen to a cell if it was placed in a hypertonic solution?
5. What is meant by concentration gradient, and how does it affect the movement of molecules?
4. Biological Molecules
1. What are the four main types of biological molecules, and what is the primary function of each?
2. How do carbohydrates provide energy to living organisms?
3. What are enzymes made of, and how do they facilitate biochemical reactions?
4. What is the role of lipids in the cell membrane?
5. Describe the structure of proteins and their role in the body.
5. Enzymes
1. What is the function of an enzyme in biochemical reactions?
2. How does the shape of an enzyme's active site relate to its specificity?
3. What is enzyme denaturation, and what can cause it?
4. How does temperature affect enzyme activity?
5. Explain the role of cofactors and coenzymes in enzyme function.
6. Plant Nutrition
1. What is photosynthesis, and where does it occur in plant cells?
2. What are the main components needed for photosynthesis?
3. How do plants obtain water, and why is it essential for photosynthesis?
4. What are the roles of the two main types of vascular tissue in plants (xylem and phloem)?
5. How does the process of transpiration help in plant nutrition?
7. Human Nutrition
1. What are the main components of a balanced diet?
2. Why is fiber important in human nutrition, and where can it be found?
3. What is the role of proteins in the human body?
4. How does the body utilize carbohydrates for energy?
5. What are vitamins and minerals, and why are they important for maintaining health?
8. Transport in Plants
1. What is the function of xylem in plants?
2. How does the phloem contribute to the transport of nutrients?
3. Explain the process of transpiration and its importance to plants.
4. What is the role of stomata in the process of gas exchange and transpiration?
5. How do root hairs facilitate the uptake of water and minerals?
9. Transport in Animals
1. What are the main components of the human circulatory system?
2. How do arteries differ from veins in structure and function?
3. What is the role of capillaries in the circulatory system?
4. Describe the pathway of blood through the heart.
5. How does the circulatory system transport oxygen and nutrients to body cells?
10. Diseases and Immunity
1. What is the difference between infectious and non-infectious diseases?
2. How do vaccines help prevent diseases?
3. What are white blood cells, and how do they protect the body from infection?
4. What is an antigen, and how does the immune system respond to it?
5. What is the role of antibodies in fighting infections?
11. Gas Exchange in Humans
1. What is the role of the alveoli in the process of gas exchange?
2. How does oxygen enter the bloodstream, and what happens to carbon dioxide?
3. What is the difference between inhalation and exhalation?
4. How do the lungs maintain efficient gas exchange?
5. What is the significance of the diaphragm in breathing?
12. Respiration
1. What is the main difference between aerobic and anaerobic respiration?
2. Write the general equation for aerobic respiration.
3. What is produced as a byproduct of anaerobic respiration in human cells?
4. How is energy released during respiration used by cells?
5. Why do muscle cells undergo anaerobic respiration during intense exercise?
13. Excretion in Humans
1. What is the role of the kidneys in the excretion process?
2. Describe the pathway urine takes from the kidneys to the outside of the body.
3. What is the function of the nephrons in the kidneys?
4. How does the excretory system help regulate water balance in the body?
5. What is the importance of excretion in maintaining homeostasis?
14. Coordination and Response
1. What is the function of the nervous system in the human body?
2. What are the major components of the human nervous system?
3. How do neurons transmit electrical impulses?
4. What is the role of the endocrine system in coordination and response?
5. How does the body respond to stimuli through the nervous system and hormones?
Answers
1. Characteristics and Classification of Living Organisms
1. What are the seven characteristics of living organisms?
2. How do plants and animals differ in terms of their nutrition?
3. What is the primary method of classification in biology, and what are the five kingdoms of life?
4. Why is the ability to reproduce considered a characteristic of life?
5. Explain the difference between unicellular and multicellular organisms.
2. Organisation of the Organism
1. What is the hierarchy of biological organization from cells to organisms?
2. How do tissues, organs, and organ systems work together to form an organism?
3. Give an example of a tissue and an organ in the human body and explain their functions.
4. What is the difference between an organ and an organ system?
5. Why is the cell considered the basic unit of life?
3. Movement into and out of Cells
1. What is the difference between diffusion and osmosis?
2. How does facilitated diffusion differ from simple diffusion?
3. Define active transport and explain why it requires energy.
4. What would happen to a cell if it was placed in a hypertonic solution?
5. What is meant by concentration gradient, and how does it affect the movement of molecules?
4. Biological Molecules
1. What are the four main types of biological molecules, and what is the primary function of each?
2. How do carbohydrates provide energy to living organisms?
3. What are enzymes made of, and how do they facilitate biochemical reactions?
4. What is the role of lipids in the cell membrane?
5. Describe the structure of proteins and their role in the body.
5. Enzymes
1. What is the function of an enzyme in biochemical reactions?
2. How does the shape of an enzyme's active site relate to its specificity?
3. What is enzyme denaturation, and what can cause it?
4. How does temperature affect enzyme activity?
5. Explain the role of cofactors and coenzymes in enzyme function.
6. Plant Nutrition
1. What is photosynthesis, and where does it occur in plant cells?
2. What are the main components needed for photosynthesis?
3. How do plants obtain water, and why is it essential for photosynthesis?
4. What are the roles of the two main types of vascular tissue in plants (xylem and phloem)?
5. How does the process of transpiration help in plant nutrition?
7. Human Nutrition
1. What are the main components of a balanced diet?
2. Why is fiber important in human nutrition, and where can it be found?
3. What is the role of proteins in the human body?
4. How does the body utilize carbohydrates for energy?
5. What are vitamins and minerals, and why are they important for maintaining health?
8. Transport in Plants
1. What is the function of xylem in plants?
2. How does the phloem contribute to the transport of nutrients?
3. Explain the process of transpiration and its importance to plants.
4. What is the role of stomata in the process of gas exchange and transpiration?
5. How do root hairs facilitate the uptake of water and minerals?
9. Transport in Animals
1. What are the main components of the human circulatory system?
2. How do arteries differ from veins in structure and function?
3. What is the role of capillaries in the circulatory system?
4. Describe the pathway of blood through the heart.
5. How does the circulatory system transport oxygen and nutrients to body cells?
10. Diseases and Immunity
1. What is the difference between infectious and non-infectious diseases?
2. How do vaccines help prevent diseases?
3. What are white blood cells, and how do they protect the body from infection?
4. What is an antigen, and how does the immune system respond to it?
5. What is the role of antibodies in fighting infections?
11. Gas Exchange in Humans
1. What is the role of the alveoli in the process of gas exchange?
2. How does oxygen enter the bloodstream, and what happens to carbon dioxide?
3. What is the difference between inhalation and exhalation?
4. How do the lungs maintain efficient gas exchange?
5. What is the significance of the diaphragm in breathing?
12. Respiration
1. What is the main difference between aerobic and anaerobic respiration?
2. Write the general equation for aerobic respiration.
3. What is produced as a byproduct of anaerobic respiration in human cells?
4. How is energy released during respiration used by cells?
5. Why do muscle cells undergo anaerobic respiration during intense exercise?
13. Excretion in Humans
1. What is the role of the kidneys in the excretion process?
2. Describe the pathway urine takes from the kidneys to the outside of the body.
3. What is the function of the nephrons in the kidneys?
4. How does the excretory system help regulate water balance in the body?
5. What is the importance of excretion in maintaining homeostasis?
14. Coordination and Response
1. What is the function of the nervous system in the human body?
2. What are the major components of the human nervous system?
3. How do neurons transmit electrical impulses?
4. What is the role of the endocrine system in coordination and response?
5. How does the body respond to stimuli through the nervous system and hormones?
1. Characteristics and Classification of Living Organisms
1. What are the seven characteristics of living organisms?
o Movement: Living organisms move, either voluntarily or due to external stimuli.
o Respiration: Organisms convert food into energy (ATP).
o Sensitivity: The ability to respond to environmental changes or stimuli.
o Growth: Organisms increase in size and complexity.
o Reproduction: The ability to produce offspring.
o Excretion: The removal of metabolic waste products.
o Nutrition: Organisms need nutrients to gain energy and grow.
2. How do plants and animals differ in terms of their nutrition?
o Plants are autotrophic, meaning they make their own food through photosynthesis
(using sunlight, carbon dioxide, and water).
o Animals are heterotrophic, meaning they obtain food by consuming other organisms.
3. What is the primary method of classification in biology, and what are the five
kingdoms of life?
o The primary method is taxonomy, which classifies organisms based on shared
characteristics.
o The five kingdoms are: Monera, Protista, Fungi, Plantae, and Animalia.
4. Why is the ability to reproduce considered a characteristic of life?
o Reproduction ensures the continuation of a species, passing on genetic information to
offspring.
5. Explain the difference between unicellular and multicellular organisms.
o Unicellular organisms consist of a single cell (e.g., bacteria).
o Multicellular organisms are made up of many cells, which may specialize in different
functions (e.g., humans, plants).
2. Organisation of the Organism
1. What is the hierarchy of biological organization from cells to organisms?
o Cell → Tissue → Organ → Organ System → Organism
2. How do tissues, organs, and organ systems work together to form an organism?
o Tissues are groups of similar cells that perform a specific function (e.g., muscle tissue).
Organs are made up of tissues working together (e.g., the heart). Organ systems consist
of organs that work together to perform vital functions (e.g., circulatory system).
3. Give an example of a tissue and an organ in the human body and explain their
functions.
o Tissue: Muscle tissue, which contracts to allow movement.
o Organ: The heart, which pumps blood throughout the body.
4. What is the difference between an organ and an organ system?
o An organ is a single structure made of tissues that performs a specific function (e.g., the
stomach). An organ system is a group of organs that work together to perform a
broader function (e.g., the digestive system).
5. Why is the cell considered the basic unit of life?
o The cell is the smallest unit that can carry out all functions necessary for life, such as
metabolism, growth, and reproduction.
3. Movement into and out of Cells
1. What is the difference between diffusion and osmosis?
o Diffusion is the movement of particles from an area of high concentration to an area of
low concentration.
o Osmosis is the movement of water molecules across a semi-permeable membrane from
an area of low solute concentration to an area of high solute concentration.
2. How does facilitated diffusion differ from simple diffusion?
o Facilitated diffusion involves the use of transport proteins to move molecules across the
membrane, while simple diffusion does not require proteins and occurs directly through
the lipid bilayer.
3. Define active transport and explain why it requires energy.
o Active transport is the movement of molecules across the cell membrane against their
concentration gradient, which requires energy (usually in the form of ATP).
4. What would happen to a cell if it was placed in a hypertonic solution?
o Water would move out of the cell, causing it to shrink (plasmolysis in plant cells).
5. What is meant by concentration gradient, and how does it affect the movement of
molecules?
o A concentration gradient is the difference in concentration of a substance between two
regions. Molecules move from an area of higher concentration to lower concentration
(down the gradient) in processes like diffusion and osmosis.
4. Biological Molecules
1. What are the four main types of biological molecules, and what is the primary
function of each?
o Carbohydrates: Provide energy (e.g., glucose).
o Proteins: Perform various functions like catalyzing reactions (enzymes), building
structures, and supporting immune function.
o Lipids: Provide energy storage, form cell membranes, and act as signaling molecules.
o Nucleic Acids: Store and transmit genetic information (DNA and RNA).
2. How do carbohydrates provide energy to living organisms?
o Carbohydrates are broken down into glucose, which is used by cells for energy through
cellular respiration.
3. What are enzymes made of, and how do they facilitate biochemical reactions?
o Enzymes are made of proteins. They lower the activation energy of biochemical
reactions, speeding up the reactions without being consumed in the process.
4. What is the role of lipids in the cell membrane?
o Lipids, particularly phospholipids, form the structure of the cell membrane, creating a
barrier that controls what enters and exits the cell.
5. Describe the structure of proteins and their role in the body.
o Proteins are made up of amino acids linked by peptide bonds. They perform numerous
functions, including acting as enzymes, hormones, antibodies, and structural
components (e.g., collagen in skin).
5. Enzymes
1. What is the function of an enzyme in biochemical reactions?
o Enzymes act as catalysts, speeding up chemical reactions without being used up in the
process.
2. How does the shape of an enzyme's active site relate to its specificity?
o The active site of an enzyme has a specific shape that only fits particular substrate
molecules, ensuring that only specific reactions are catalyzed.
3. What is enzyme denaturation, and what can cause it?
o Denaturation is the loss of an enzyme's three-dimensional structure, which makes it
inactive. It can be caused by extreme temperature or pH changes.
4. How does temperature affect enzyme activity?
o As temperature increases, enzyme activity generally increases (up to a point). Beyond
the optimal temperature, enzymes may denature and lose their function.
5. Explain the role of cofactors and coenzymes in enzyme function.
o Cofactors are non-protein molecules that help enzymes function (often inorganic ions
like metal ions). Coenzymes are organic molecules (often vitamins) that assist in enzyme
activity.
6. Plant Nutrition
1. What is photosynthesis, and where does it occur in plant cells?
o Photosynthesis is the process by which plants convert light energy into chemical energy,
producing glucose and oxygen. It occurs in the chloroplasts.
2. What are the main components needed for photosynthesis?
o Carbon dioxide (CO₂), water (H₂O), and light energy (usually from the sun).
3. How do plants obtain water, and why is it essential for photosynthesis?
o Water is absorbed by roots from the soil and transported through the xylem to the
leaves. Water is used in the photosynthesis process to produce glucose and oxygen.
4. What are the roles of the two main types of vascular tissue in plants (xylem and
phloem)?
o Xylem transports water and minerals from the roots to the rest of the plant.
o Phloem transports sugars and other nutrients produced in the leaves to other parts of
the plant.
5. How does the process of transpiration help in plant nutrition?
o Transpiration is the evaporation of water from plant leaves. It creates a negative
pressure that helps pull water and minerals up from the roots through the xylem.
7. Human Nutrition
1. What are the main components of a balanced diet?
o Carbohydrates, proteins, fats, vitamins, minerals, fiber, and water.
2. Why is fiber important in human nutrition, and where can it be found?
o Fiber aids digestion, helps regulate bowel movements, and may prevent certain
diseases. It can be found in fruits, vegetables, whole grains, and legumes.
3. What is the role of proteins in the human body?
o Proteins are essential for growth, repair of tissues, immune function, and as enzymes
and hormones.
4. How does the body utilize carbohydrates for energy?
o Carbohydrates are broken down into glucose, which is used by cells to produce ATP
(energy) via cellular respiration.
5. What are vitamins and minerals, and why are they important for maintaining
health?
o Vitamins are organic compounds necessary for various biochemical functions (e.g.,
Vitamin C supports immune function). Minerals are inorganic elements vital for
processes like nerve transmission (e.g., calcium for bones).
8. Transport in Plants
1. What is the function of xylem in plants?
o Xylem transports water and dissolved minerals from the roots to
4o mini
