CBSE Class 7 Science Important Questions

Below are 10 Important Questions from Class 7 Science chapters that are Important for preparing well and understanding concepts easily.

1. What is photosynthesis, and why is it important for plants?

Ans: Photosynthesis is the process by which green plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. It occurs in the chloroplasts of plant cells, primarily in the leaves. This process is crucial for plants as it provides food and energy necessary for growth and development. Additionally, photosynthesis produces oxygen, which is essential for the survival of most living organisms, making it a vital part of the Earth's ecosystem.

2. How do animals obtain their nutrients?

Ans: Animals obtain nutrients through a process called ingestion, where they consume food. The food is then digested in the digestive system, which breaks it down into simpler substances. Nutrients such as carbohydrates, proteins, fats, vitamins, and minerals are absorbed into the bloodstream and transported to various body cells. This process provides energy for growth, repair, and maintenance of body functions, ensuring the animal's overall health.

3. What is heat, and how does it transfer?

Ans: Heat is a form of energy that is transferred between objects due to a temperature difference. It can be transferred in three ways: conduction (direct contact), convection (through fluids), and radiation (through electromagnetic waves). For example, when a metal spoon is placed in hot water, heat transfers through conduction, warming the spoon. In convection, hot air or liquid rises, and cooler areas fill the gap, while radiation transfers heat through empty space, such as the warmth felt from the sun.

4. What are acids, bases, and salts? Provide examples.

Ans: Acids are substances that release hydrogen ions (H⁺) in solution and typically have a sour taste; examples include hydrochloric acid (found in the stomach) and citric acid (in citrus fruits). Bases are substances that release hydroxide ions (OH⁻) and often feel slippery; examples include sodium hydroxide (used in drain cleaners) and baking soda. Salts are formed when an acid reacts with a base; for example, sodium chloride (table salt) is produced from hydrochloric acid and sodium hydroxide.

5. What is the difference between physical and chemical changes?

Ans: Physical changes are changes that affect the form or appearance of a substance but do not change its chemical composition. Examples include melting ice or dissolving sugar in water. Chemical changes involve a change in the substance's chemical composition, resulting in new substances being formed. Indicators of chemical changes include colour change, gas production, and temperature changes, such as rusting of iron or burning wood.

6. What is respiration, and how do organisms respire?

Ans: Respiration is the process by which organisms convert glucose and oxygen into energy, carbon dioxide, and water. There are two types of respiration: aerobic (involving oxygen) and anaerobic (without oxygen). Most animals and plants perform aerobic respiration, while some microorganisms may carry out anaerobic respiration. The energy produced during respiration is vital for growth, movement, and cellular processes, enabling organisms to function effectively.

7. How do plants and animals transport substances in their bodies?

Ans: In plants, transportation occurs through the xylem and phloem. The xylem transports water and minerals from the roots to other parts, while the phloem carries food (sugars) from the leaves to the rest of the plant. In animals, the circulatory system, which includes the heart and blood vessels, transports oxygen, nutrients, hormones, and waste products throughout the body. This transportation system is essential for maintaining homeostasis and supporting life functions.

8. What are the different methods of reproduction in plants?

Ans: Plants reproduce through two main methods: sexual and asexual reproduction. Sexual reproduction involves the formation of seeds through the fertilisation of ovules by pollen, leading to the growth of new plants. This process results in genetic variation. Asexual reproduction occurs without seeds and includes methods like budding, cutting, and layering, allowing plants to reproduce quickly and efficiently, producing genetically identical offspring.

9. What is motion, and how is it measured?

Ans: Motion refers to the change in position of an object with respect to time. It can be measured using distance and time. Speed is calculated as the distance travelled divided by the time taken. For example, if a car travels 100 km in 2 hours, its speed is 50 km/h. Different types of motion include linear motion (straight line), circular motion (in a circle), and oscillatory motion (back and forth), each characterized by specific patterns of movement.

10. What are the effects of electric current?

Ans: Electric current can produce several effects, including heating, magnetic, and chemical effects. The heating effect occurs in devices like electric heaters and toasters, where current generates heat. The magnetic effect is observed in electromagnets, where current creates a magnetic field that can attract or repel other magnetic materials. The chemical effect is seen in electrolysis, where current causes chemical reactions, such as the splitting of water into hydrogen and oxygen gas.

How do Science Important Questions Class 7 Help you with Exams?

• Important questions for Class 7 Science guide students to focus on key concepts and topics, ensuring they study the most relevant material for exams.

• By answering these questions, students enhance their understanding of scientific principles, which helps in grasp complex ideas more effectively.

• Engaging with important questions improves memory retention, as students actively recall and summarise information, making it easier to remember during exams.

• Practising these questions helps develop writing skills, enabling students to articulate their thoughts clearly and organize their answers better.

• Important questions familiarise students with the types of questions they may encounter in exams.

• Responding to these questions encourages critical thinking and analysis, allowing students to interpret scientific concepts and apply them to different situations.

• Working through important questions helps students identify their strengths and weaknesses, allowing them to focus on areas that need improvement before the exam.

CBSE Class 7 Science Important Questions are essential tools for effective exam preparation. They help students focus on key topics and concepts, improving their understanding of the subject. By practising these questions, students can enhance their writing skills and build confidence for the exams. Additionally, they provide valuable insights into the types of questions that may appear in tests. Engaging with important questions also promotes critical thinking and better retention of information. Overall, these questions support students in achieving success in their Science studies and help them feel well-prepared for their exams.

Additional Study Materials for Class 7 Science