Cell and Human Biology
Cell and Human Biology
1. The organ that helps in hearing and balance is – Ear
The ear detects sound vibrations and maintains balance through the cochlea and vestibular system. The inner ear contains semicircular canals for equilibrium.
2. The fluid that lubricates joints in the body is – Synovial fluid
Synovial fluid is a viscous liquid in movable joints. It reduces friction, nourishes cartilage, and allows smooth, pain-free movement of bones at joints.
3. The outermost layer of a plant leaf is – Cuticle
The cuticle is a waxy protective layer covering leaves. It prevents water loss, protects against pathogens, and reduces damage from sunlight and environmental stress.
4. The organism that prepares its own food is called – Autotroph
Autotrophs synthesize food from sunlight (photosynthesis) or chemicals (chemosynthesis). Examples include plants, algae, and some bacteria.
5. The organism that depends on others for food is called – Heterotroph
Heterotrophs cannot make their own food. They feed on plants, animals, or organic matter. Examples include humans, animals, fungi, and most bacteria.
6. The process of taking in food by an organism is – Ingestion
Ingestion is the intake of food into the body via mouth or other feeding structures. It is the first step in the digestive process.
7. The breakdown of food into simpler substances is – Digestion
Digestion is the chemical and mechanical process of breaking down complex food molecules into simpler forms like glucose, amino acids, and fatty acids for absorption.
8. The large intestine mainly absorbs – Water
The large intestine absorbs water and salts from undigested food, forming solid feces. It houses beneficial bacteria that help in fermentation and vitamin production.
9. The number of chromosomes in human body cells – 46
Humans have 46 chromosomes (23 pairs) in somatic cells. They carry genetic information essential for growth, development, and reproduction.
10. The number of chromosomes in human gametes – 23
Human gametes (sperm and egg) have 23 chromosomes, half of the somatic cell count. Fertilization restores the diploid number (46).
11. The organ that produces bile juice – Liver
The liver secretes bile, a greenish fluid containing bile salts that emulsify fats, aiding digestion and absorption in the small intestine.
12. The organ that stores bile – Gall Bladder
The gall bladder stores and concentrates bile from the liver. It releases bile into the small intestine to digest fats during meals.
13. The process of removal of waste from the body – Excretion
Excretion is the elimination of metabolic wastes like urea, CO₂, and excess salts from the body to maintain homeostasis and prevent toxicity.
14. The part of the plant responsible for reproduction – Flower
Flowers are reproductive structures in angiosperms. They contain male (stamens) and female (carpels) organs that enable pollination and seed production.
15. The thread-like structures that carry genes – Chromosomes
Chromosomes are DNA-protein complexes in the nucleus. They carry hereditary information (genes) and ensure accurate transmission of traits during cell division.
16. The process of loss of water vapor from leaves – Transpiration
Transpiration is the evaporation of water from plant leaves through stomata. It regulates temperature, maintains water movement, and facilitates nutrient transport.
17. The tissue that carries food in plants – Phloem
Phloem is vascular tissue that transports organic food (mainly sugars) from leaves to stems, roots, and storage organs. It supports growth and metabolism.
18. The tissue that carries water in plants – Xylem
Xylem is vascular tissue that conducts water and minerals from roots to leaves, providing mechanical support and facilitating transpiration-driven movement.
19. The cell organelle known as the control center – Nucleus
The nucleus contains genetic material (DNA), controls cellular activities, directs protein synthesis, and regulates growth, reproduction, and metabolism.
20. The transparent front part of the eye – Cornea
The cornea is a transparent, curved layer covering the eye’s front. It refracts light, protects inner structures, and contributes to focusing images on the retina.
21. The pigment that gives red color to blood – Hemoglobin
Hemoglobin is an iron-containing protein in red blood cells. It binds oxygen in lungs and carries it to tissues, giving blood its red color.
22. The type of joint found in the shoulder – Ball and Socket Joint
The shoulder joint is a ball-and-socket joint, allowing multidirectional movement. The humerus fits into the scapula socket for flexibility and rotation.
23. The largest bone in the human body – Femur
The femur is the thigh bone, the strongest and longest bone. It supports body weight, enables leg movement, and forms part of the hip and knee joints.
24. The smallest bone in the human body – Stapes
The stapes is in the middle ear. It transmits sound vibrations from the incus to the inner ear, enabling hearing.
25. The muscle that controls breathing – Diaphragm
The diaphragm is a dome-shaped muscle under the lungs. Its contraction and relaxation change chest volume, allowing inhalation and exhalation.