Question 3
How is oxygen and carbon dioxide transported in human beings?
In human beings, the respiratory pigment is haemoglobin which has a very high affinity for oxygen. This pigment is present in the red blood corpuscles and is responsible for transportation of oxygen. Carbon dioxide is more soluble in water than oxygen is and hence is mostly transported in the dissolved form in our blood.
Chapter 5: Life Processes — Quick Revision Guide
Introduction
Life processes are the basic functions performed by all living organisms to sustain life. This chapter covers nutrition (autotrophic and heterotrophic), respiration, transportation, and excretion in plants and animals.
Key Points at a Glance
- Photosynthesis: 6CO2 + 6H2O → C6H12O6 + 6O2 (in chloroplasts using chlorophyll and sunlight)
- Stomata: tiny pores for gas exchange and transpiration; guard cells control opening/closing
- Human digestive system: mouth (salivary amylase) → stomach (HCl, pepsin) → small intestine (bile, trypsin, lipase; absorption by villi) → large intestine → anus
- Aerobic respiration (mitochondria): glucose + O2 → CO2 + H2O + 38 ATP
- Anaerobic: in yeast → ethanol + CO2; in muscles → lactic acid; both yield 2 ATP
- Xylem: transports water upward (dead cells, transpiration pull); Phloem: transports food bidirectionally (living cells, uses ATP)
- Heart: 4 chambers, double circulation (pulmonary + systemic); septum prevents mixing
- Blood: plasma + RBCs (O2 via haemoglobin) + WBCs (immunity) + platelets (clotting)
- Nephron: Bowman's capsule + glomerulus → filtration → reabsorption → urine; dialysis for kidney failure
- Plant excretion: transpiration, leaf fall, stored in vacuoles, resins/gums
Real-World Connections
Photosynthesis is the basis of all food chains; fermentation used in bread and alcohol production; blood donation saves lives; dialysis machines sustain patients with kidney failure.
Quick Self-Test (5 Questions)
- What is the most important concept you learned from this chapter?
- Can you write three key equations/formulae from this chapter from memory?
- Draw a labelled diagram relevant to this chapter without looking at your notes.
- Explain one real-world application of a concept from this chapter.
- What is one common mistake students make in this chapter, and how can you avoid it?
Further Study
- NCERT Textbook Chapter 5
- NCERT Exemplar Problems
- Bright Tutorials Detailed Notes: ch05-life-processes.html
- Bright Tutorials Practice Questions: ch05-life-processes.html
- Previous Year CBSE Board Papers