Bihar Science Quarterly Exam - Class 10 Bihar Board Science

Science: Key Concepts and Exam-Focused Questions

Nutrition and Biological Processes

Nutrition in living organisms involves the intake and utilization of food for energy and growth. Fungi exhibit saprophytic nutrition, feeding on decaying organic matter. Digestion in humans begins in the buccal cavity (mouth), not in the stomach or intestines. Biological processes in living organisms include respiration, nutrition, and reproduction.

• Fungi Nutrition: Saprophytic (feeds on dead/decaying matter)
• Human Digestion: Begins in the buccal cavity (mouth)
• Key Biological Processes: Respiration, nutrition, reproduction (all are present in living organisms)
• Fermentation: Occurs in yeast, not in hydra or…

Science: Key Concepts and Exam-Focused Questions

Nutrition and Biological Processes

Nutrition in living organisms involves the intake and utilization of food for energy and growth. Fungi exhibit saprophytic nutrition, feeding on decaying organic matter. Digestion in humans begins in the buccal cavity (mouth), not in the stomach or intestines. Biological processes in living organisms include respiration, nutrition, and reproduction.

• Fungi Nutrition: Saprophytic (feeds on dead/decaying matter)
• Human Digestion: Begins in the buccal cavity (mouth)
• Key Biological Processes: Respiration, nutrition, reproduction (all are present in living organisms)
• Fermentation: Occurs in yeast, not in hydra or amoeba
• Aerobic Respiration: Oxygen is taken in during this process
• Cellular Fuel: Glucose is the main fuel for cells
• Transpiration in Plants: Mainly occurs through leaves
• Human Heart: Part of the circulatory system

Blood, Excretion, and Plant Waste

Blood clotting is facilitated by specific factors, and excretion is essential for removing metabolic waste. Plants store waste in various parts, and the kidney is the main excretory organ in humans.

• Blood Clotting: Fibrinogen is a key clotting factor (not platelets in the options)
• Plant Waste Storage: Bark, vacuoles, and leaves can all store plant waste
• Amino Acid Breakdown: Produces ammonia as a metabolic waste
• Kidney Function: Main function is excretion (removal of metabolic waste)

Hormones and Nervous System

Hormones regulate various physiological processes. Plant hormones like cytokinin and ethylene play roles in cell division and fruit ripening. The nervous system transmits information via neurons, with dendrites acquiring information.

• Plant Hormone: Cytokinin (cell division), ethylene (fruit ripening)
• Fruit Ripening Hormone: Ethylene
• Cranial Nerves in Humans: 12 pairs
• Spinal Nerves in Humans: 31 pairs
• Blood Pressure Regulation: Controlled by adrenal gland (adrenaline hormone)
• Neuron Information Acquisition: Dendrites
• Emergency Hormone: Adrenaline (from adrenal gland)
• Involuntary vs Voluntary Actions: Chewing is voluntary; vomiting, salivation, and heartbeat are involuntary

Vision and Eye Structure

The human eye forms images on the retina, with the cornea being the transparent front part. Defects like presbyopia are corrected with bifocal lenses. Rod cells are sensitive to dim light, and the blind spot lacks rod and cone cells.

• Image Formation: On retina (real and inverted)
• Transparent Front Part: Cornea
• Bifocal Lens: Corrects presbyopia
• Rod Cells: Sensitive to dim light (night vision)
• Blind Spot: No rod or cone cells present
• Maximum Refraction in Eye: Occurs at the outer surface of the cornea
• Least Distance of Distinct Vision: 25 cm

Light, Reflection, and Refraction

Light exhibits reflection and refraction. Plane mirrors have infinite focal length, and real images are always formed in front of the mirror. The angle between incident and reflected rays is twice the angle of incidence.

• Focal Length of Plane Mirror: Infinite
• Real Image Formation: In front of the mirror
• Angle Between Incident and Reflected Ray: If angle of incidence is $30^\circ$, the angle between rays is $60^\circ$
• Speed of Reflected Light: Remains the same as incident light ($c$)
• Origin in Spherical Mirror (Cartesian Sign Convention): Pole
• Light Speed Change: Increases when moving from denser to rarer medium
• Change During Refraction: Only wavelength changes, not frequency or color
• Power of Lens Formula: $P = \frac{100}{\text{focal length in cm}}$
• Diverging Lens: Concave lens
• Magnified Image: Formed by concave mirror
• Dispersion of Light: Produced by prism

Chemistry: Reactions and Gases

Chemical reactions include combination, decomposition, and redox processes. Respiration is an exothermic reaction. Loss of oxygen during a reaction is called reduction. Decomposition of vegetable matter is exothermic.

• Zn + Dil. HCl Reaction: Produces hydrogen gas
• Respiration: Exothermic reaction
• Loss of Oxygen: Reduction
• Decomposition of Vegetable Matter: Exothermic reaction
• Combination Reaction Example: $2H_2 + O_2 \rightarrow 2H_2O$
• Gas in Chips Packets: Nitrogen (prevents oxidation)
• Rusting of Iron: Corrosion
• Arrow in Chemical Equation: Indicates direction of reaction
• Burning Magnesium Ribbon: Produces dazzling white flame
• Balanced Equation Example: $N_2 + 3H_2 \rightarrow 2NH_3$
• Formation of CaO from CaCO3: Decomposition reaction
• Substances Preventing Oxidation: Antioxidants

Plant Physiology and Growth

Plant hormones regulate growth and development. Cytokinin promotes cell division, gibberellin is a growth hormone, and ethylene is responsible for fruit ripening. Stomata are involved in gas exchange, and transpiration mainly occurs through leaves.

• Plant Growth Hormone: Gibberellin
• Hormone Secretion: From endocrine glands
• Thyroxine Synthesis: Requires iodine
• Stomata: Pores for gas exchange and transpiration

Physics: Lenses, Mirrors, and Optical Phenomena

Lenses and mirrors form images based on their shapes and properties. Concave lenses are diverging, and concave mirrors can form magnified images. The focal length of the eye lens is changed by ciliary muscles. Dispersion of white light into seven colors is caused by a prism.

• Diverging Lens: Concave lens
• Magnified Image: By concave mirror
• Image in Human Eye: Formed on retina
• Transparent Front Part of Eye: Cornea
• Focal Length Change in Eye: By ciliary muscles
• Dispersion of Light: By prism

Color and Scattering of Light

Scattering of light in the atmosphere explains the color of the sky and the appearance of the sun at sunrise and sunset. Blue light scatters the most due to its shortest wavelength, while red light scatters the least due to its longest wavelength.

• Maximum Scattering: Blue light
• Minimum Scattering: Red light
• Reason for Red Signals: Red light scatters least

Subjective Exam Questions (Stated)

A set of subjective questions was provided for practice, focusing on definitions, functions, diagrams, and explanations. These include:

• Definition and function of villi
• What are stomata and their functions
• Removal of metabolic waste in unicellular organisms
• Dialysis and its purpose
• Types of nutrition (autotrophic, heterotrophic)
• Neurotransmitter definition and nervous system functions
• Role of ethylene in fruit ripening
• Phototropism definition
• Diagram and explanation of the nervous system
• Magnification and why concave lens is diverging
• Lateral displacement and its explanation
• Laws of refraction and ray diagrams
• Power of accommodation and vision defects
• Reason for red appearance of the sun at sunrise/sunset
• Prism diagram
• Combination reaction, rancidity, balanced chemical equation, precipitation reaction
• Balancing a given chemical equation

These questions are to be answered in detail for thorough exam preparation.