MCQ’s
Notes with Exercise
Class 11th Biology Chapter 14, Transport, focuses on how substances move within living organisms, such as plants and animals. Here’s a general overview:
- Transport in Plants:
- Xylem: Transports water and dissolved minerals from the roots to other parts of the plant, primarily through the process of transpiration.
- Phloem: Moves organic nutrients, like sugars produced during photosynthesis, from the leaves to other parts of the plant. This process is called translocation.
- Mechanisms:
- Transpiration Pull: Water evaporates from the leaves, creating a suction force that pulls water upward from the roots.
- Root Pressure: Pressure generated in the roots helps push water up through the xylem.
- Capillary Action: Water molecules rise in the thin tubes of xylem due to cohesion (attraction between water molecules) and adhesion (attraction between water and xylem walls).
- Transport in Humans and Animals:
- Circulatory System: Responsible for the transport of oxygen, carbon dioxide, nutrients, and waste products throughout the body.
- Blood: Acts as the medium of transport, composed of red blood cells (for oxygen transport), white blood cells (for immunity), platelets (for clotting), and plasma (for transporting dissolved substances).
- Heart: Pumps blood through the body in a double circulation system (pulmonary and systemic circulation).
- Pulmonary Circulation: Blood flows from the heart to the lungs and back, exchanging carbon dioxide for oxygen.
- Systemic Circulation: Oxygenated blood is distributed to the body, delivering oxygen and nutrients, and collecting waste products like carbon dioxide.
- Blood Vessels: Arteries carry oxygen-rich blood from the heart, veins bring oxygen-poor blood back, and capillaries are small vessels where gas and nutrient exchange occurs.
- Circulatory System: Responsible for the transport of oxygen, carbon dioxide, nutrients, and waste products throughout the body.
- Lymphatic System:
- A network of vessels that transport lymph, a fluid containing white blood cells and other immune cells.
- Plays a crucial role in immunity and helps remove excess fluid from tissues.
- Transport in Other Organisms:
- Invertebrates: Use simpler circulatory systems like open circulatory systems where the blood (hemolymph) directly bathes organs, unlike closed systems in vertebrates.
- Single-celled Organisms: Rely on diffusion to move nutrients, gases, and wastes across their cell membrane.
- Importance of Transport:
- Essential for the distribution of oxygen, nutrients, hormones, and removal of waste products.
- Helps maintain homeostasis by regulating fluid balance, temperature, and pH levels.
This chapter highlights the various systems and mechanisms that organisms use to transport essential substances, ensuring survival and proper function.