Class 10 Science - Life Processes

Comprehensive practice flashcards covering Nutrition, Respiration, Transportation, and Excretion in plants and animals based on Class 10 Science lecture notes.

What are life processes?

The basic and essential activities performed by a living organism to sustain and maintain life (such as nutrition, respiration, transportation, and excretion).

What is nutrition, and what are the primary components of food?

Nutrition is the process by which a living organism obtains and utilises food for energy, growth, and development. Its key components are carbohydrates, proteins, fats, and vitamins & minerals.

How does autotrophic nutrition differ between chemosynthesis and photosynthesis?

Chemosynthesis utilises chemical energy to prepare food (e.g., purple sulfur bacteria), whereas photosynthesis utilises light energy to prepare food (e.g., green plants, cyanobacteria, algae, Euglena).

What are the three main types of heterotrophic nutrition?

1. Holozoic: Taking in solid food broken down inside the body (e.g., Amoeba, animals).
2. Saprophytic: Feeding on dead and decaying matter (e.g., fungi).
3. Parasitic: Living inside or outside a host to derive nutrition from it without necessarily killing it (e.g., Cuscuta, ticks, leeches).

What is the balanced chemical equation representing the process of photosynthesis?

$6\text{CO}_2 + 12\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 + 6\text{H}_2\text{O}$ in the presence of chlorophyll and sunlight.

What are the three main events that occur during photosynthesis?

1. Absorption of light energy by chlorophyll.
2. Conversion of light energy into chemical energy and splitting of water into hydrogen and oxygen.
3. Reduction of $\text{CO}_2$ to carbohydrates.

In what form do plants store excess glucose compared to humans according to the lecture notes?

Plants store glucose in the form of starch, while humans store glucose in the form of "glucose".

How do guard cells regulate the opening and closing of stomata shown in the diagram?

Stomata open when water enters the guard cells causing them to swell (become turgid), and they close when water leaves causing the guard cells to shrink (become flaccid).

How do desert plants adapt their photosynthetic process to conserve water?

They keep stomata closed during the day to prevent water loss and open them at night to take in $\text{CO}_2$, which is stored and then used for photosynthesis during the day.

What is the role of potassium hydroxide ($\text{KOH}$) in the bell jar photosynthesis experiment shown?

$\text{KOH}$ absorbs carbon dioxide from the air inside the bell jar, creating a $\text{CO}_2$-free environment to demonstrate that $\text{CO}_2$ is essential for photosynthesis.

Which process and structures are depicted in this illustration of single-celled holozoic ingestion?

Phagocytosis/Ingestion in Amoeba, where finger-like extensions called pseudopodia encircle a food particle to form a food vacuole.

How does ingestion occur in the organism shown in the diagram?

Paramecium uses hair-like structures called cilia to sweep food particles through the oral groove into the mouth/gullet, where a food vacuole forms.

What is the function of salivary amylase in the human mouth?

Salivary amylase is an enzyme in saliva that breaks down starch into simpler sugars.

What is peristalsis?

The rhythmic contraction and relaxation of the muscles in the wall of the alimentary canal that pushes food downward through the oesophagus to the stomach.

What are the three main components of gastric juice and their specific functions?

1. Hydrochloric acid ($\text{HCl}$): Creates an acidic medium, activates pepsin, and kills harmful germs.
2. Pepsin: Digests proteins into simpler peptides.
3. Mucus: Protects the inner lining of the stomach from the corrosive action of the acid.

What two critical roles does bile juice play in digestion?

1. It makes the acidic food coming from the stomach alkaline so pancreatic enzymes can act.
2. It emulsifies fats by breaking large fat globules into smaller droplets.

What are the final breakdown products of proteins, carbohydrates, and fats in the small intestine?

Proteins are converted into amino acids, carbohydrates into glucose, and fats into fatty acids plus glycerol.

What are villi, and how do they facilitate absorption in the small intestine?

Villi are finger-like projections on the inner wall of the small intestine. They increase the surface area for absorption and are richly supplied with blood capillaries to rapidly transport absorbed nutrients.

Why do herbivores have a longer small intestine than carnivores?

Herbivores eat plant material rich in cellulose, which is hard to digest and requires a longer digestive system for complete breakdown and absorption.

How do breathing and cellular respiration differ?

Breathing is a physical, extracellular exchange of gases without enzyme involvement or energy release; respiration is a biochemical, intracellular process involving enzymes where glucose is oxidized to release energy in the form of $\text{ATP}$.

What is the fate of glucose in yeast during anaerobic respiration (alcoholic fermentation)?

Glucose is converted in the cytoplasm to pyruvate, which in the absence of oxygen produces ethanol, carbon dioxide ($\text{CO}_2$), and energy ($2\text{ ATP}$).

What causes muscle cramps during vigorous physical exercise?

The rapid conversion of glucose to pyruvate and then to lactic acid due to a lack of oxygen in muscle cells; the accumulation of lactic acid causes cramps and fatigue.

Why are rings of cartilage present in the trachea?

To ensure that the air passage remains open and does not collapse when there is less air in it.

How are alveoli structurally adapted for efficient gas exchange?

They are tiny balloon-like sacs with extremely thin, moist walls, surrounded by an extensive network of blood capillaries, providing a huge surface area for gas diffusion.

What is the order of affinity of haemoglobin for carbon monoxide, oxygen, and carbon dioxide?

$$\text{CO} > \text{O}_2 > \text{CO}_2$$

Why do aquatic organisms have a faster breathing rate than terrestrial organisms?

Because the concentration of dissolved oxygen in water is much lower than the oxygen content of air.

What are the four components of human blood and their functions?

1. Plasma: Fluid medium carrying nutrients, wastes, and hormones.
2. Red Blood Cells (RBCs): Contain haemoglobin to transport $\text{O}_2$ and $\text{CO}_2$.
3. White Blood Cells (WBCs): Provide immunity by destroying pathogens.
4. Platelets: Facilitate blood clotting to prevent leaks and bleeding.

How do arteries and veins differ in wall thickness, internal pressure, and valve presence?

Arteries have thick, elastic walls, carry blood under high pressure, and lack valves. Veins have thin walls, carry blood under low pressure, and possess valves to prevent backflow.

Which artery carries deoxygenated blood, and which vein carries oxygenated blood?

The pulmonary artery carries deoxygenated blood (from heart to lungs), and the pulmonary vein carries oxygenated blood (from lungs to heart).

Why do the ventricles of the heart have thicker muscular walls than the atria?

Ventricles have to pump blood out of the heart into distant organs at high pressure (right ventricle to lungs, left ventricle to the entire body), whereas atria only receive blood and push it into the ventricles.

What is double circulation, and what are its two pathways in humans?

A system where blood passes through the heart twice during one complete cycle. The two pathways are pulmonary circulation (heart to lungs and back) and systemic circulation (heart to body tissues and back).

How many heart chambers do fishes, amphibians, reptiles, birds, and mammals have?

Fishes have $2$ chambers; amphibians and most reptiles have $3$ chambers; birds and mammals have $4$ chambers.

What is lymph (tissue fluid) and what are its main functions?

A colourless fluid containing less protein than plasma that filters into intercellular spaces. It transports digested/absorbed fats from the intestine, drains excess extracellular fluid back into the blood, and carries lymphocytes for immune defense.

What are the key structural and functional differences between xylem and phloem?

Xylem consists mainly of dead elements, transports water and minerals unidirectionally (upward) via root pressure and transpiration pull. Phloem consists mainly of living elements, transports food (sucrose) bidirectionally via energy-requiring translocation ($\text{ATP}$).

What is transpiration and what primary role does it serve in plants?

The loss of water vapour through stomata. It generates the suction force (transpiration pull) that drives the upward movement of water and minerals (ascent of sap) and cools the plant.

What are the three fundamental steps of urine formation in a nephron?

1. Glomerular Filtration: Ultrafiltration of blood in Bowman's capsule.
2. Selective Reabsorption: Useful substances (glucose, amino acids, salts, water) are reabsorbed into blood capillaries.
3. Tubular Secretion: Extra wastes (urea, ions, excess water) are secreted into the collecting tubule.

What is hemodialysis?

A medical procedure using an artificial kidney machine to filter metabolic wastes, excess salts, and fluid from the blood in patients experiencing kidney failure.

What are four methods through which plants excrete waste products?

1. Diffusion of gaseous wastes ($\text{CO}_2$, $\text{O}_2$) through stomata.
2. Removal of excess water by transpiration.
3. Shedding of dead parts like old leaves and bark.
4. Storing resins and gums in old xylem cells, or secreting wastes into surrounding soil.