Topics to be learn :

  • Living organisms and life processes.
  • Living organisms and energy production.
  • Some nutrients and energy efficiency.
  • Cell division - A life process.

Functions of Food Stuffs and Their Nutrients:

  • Energy Source: Body needs continuous energy.
  • Food Digestion: Food is digested into soluble nutrients.
  • Nutrient Transport: Nutrients carried by blood to every cell.
  • Oxygen Transport: Oxygen carried to every cell for respiration.
  • Energy Production: Oxygen oxidizes nutrients in cells to produce energy.
  • Body Functions: Energy helps body functions; nutrients aid growth and development.

Importance of Balanced Diet:

  • Nutrient Proportions: Carbohydrates, proteins, fats, vitamins, and minerals in right proportions.
  • Specific Functions: Each nutrient has specific functions.
  • Health Maintenance: Balanced diet important for health.

Functions of Muscles in Body:

  • Voluntary Muscles: Move according to will.
  • Involuntary Muscles: Control vital activities; e.g., visceral organs.
  • Cardiac Muscles: Control heart movements.
  • Nutrient Storage: Carbohydrates and proteins stored in muscles.

Importance of Digestive Juices:

  • Enzyme Presence: Digestive juices contain enzymes.
  • Catalysts: Enzymes speed up chemical reactions.
  • pH Regulation: Stomach juices make pH acidic; intestinal juices make it alkaline.

Excretory System: Waste Removal: Removes nitrogenous waste from body.

Circulatory System:

  • Nutrient Transport: Glucose from digestive system, oxygen from respiratory system to every cell.
  • Red Blood Cells: Carry oxygen; pumped by heart.
  • Energy Production: Glucose oxidized in cells with oxygen.

Living Organisms and Life Processes:

  • System Coordination: Different systems work together in living organisms.
  • Homeostasis: Advanced in human body.
  • Coordinated Systems: Digestive, respiratory, circulatory, excretory, nervous systems, and internal organs work together.
  • Nutrient Transport: Circulatory system transports digested nutrients to cells.
  • Energy Sources: Carbohydrates, fats, and lipids provide energy.
  • Mitochondrial Role: Mitochondria synthesize energy from nutrients in cell cytoplasm.
  • Importance of Oxygen: Oxygen is essential for energy production.
  • Nutrient and Oxygen Transport: Circulatory system transports nutrients and oxygen to cells.
  • Nervous System Control: Controls actions, maintaining life, and aiding growth and development.

Plants' Life Processes:

  • Autotrophic Nature: Synthesize own food via photosynthesis.
  • Food Storage: Stored in fruits, roots, stem-tubers, leaves, etc.
  • Human and Animal Nutrition: Obtain nutrients from plants.

Carbohydrates:

  • Sources: Milk, fruits, jaggery, cane sugar, cereals, vegetables, potatoes, sweet potatoes, sweetmeats.
  • Functions: Provide 4 Kcal energy per gram.

Respiration:

 

  • Release of Energy: From assimilated food.
  • Breathing: Inhalation and exhalation.
  • Gas Exchange: Oxygen in, carbon dioxide out.
  • External Respiration: Oxygen to blood, CO2 out through alveolar membrane.
  • Internal Respiration: Oxygen to cells, energy produced in mitochondria.
  • Energy Form: ATP produced by oxidation of nutrients.

Living Organism and Energy Production:

  • Body Level Respiration: Exchange of oxygen and carbon dioxide with surroundings.
  • Cellular Level Respiration: Oxidation of foodstuffs in cells.

Cellular Level Respiration:

  • Dietary Carbohydrates: Used for ATP production.
  • Oxidation of Glucose: Step-by-step process.
  • Two Methods: Aerobic (with oxygen) and Anaerobic (without oxygen).

Aerobic Respiration:

  1. Glycolysis:

    • Glucose oxidized into pyruvic acid, ATP, NADH, water.
    • Takes place in cytoplasm.
    • Pyruvic acid converted to Acetyl-CoA, NADH2, CO2.

  2. Tricarboxylic Acid Cycle (TCA):

    • Acetyl-Co-A enters mitochondria.
    • Acetyl part oxidized, releasing CO2, H2O, NADH2, FADH2.
     

  3. Electron Transfer Chain (ETC):

    • Occurs in mitochondria.
    • NADH2, FADH2 participate.
    • NADH2 produces 3 ATP, FADH2 produces 2 ATP.
    • ATP and water produced.
    Glucose oxidation yields CO2, H2O, and energy in presence of oxygen.

Coenzymes in Cellular Respiration:

  • NADH2: Nicotinamide Adenine Dinucleotide.
  • FADH2: Flavin Adenine Dinucleotide.
  • Formed in cells, participate in respiration.

Utilization of Lipids and Proteins:

  • Lipids: Converted to fatty acids, then Acetyl-Co-A.
  • Proteins: Broken down to amino acids, then Acetyl-Co-A.
  • Acetyl-Co-A undergoes complete oxidation via Krebs cycle for energy release.

ATP (Adenosine Triphosphate):

  • Energy Storage: Energy stored in phosphate bonds.
  • Cellular Storage: Stored in cells as needed.
  • Chemical Composition: Adenosine ribonucleoside, containing adenine, ribose, three phosphate groups.
  • Energy Currency: ATP breaks phosphate bond to release energy, known as 'energy currency' of the cell.

 

Glucose Molecule:

  • Chemical Formula: C₆H₁₂O₆.
  • Covalent Bonds: Hold atoms together.
  • Oxidation: Gain oxygen atoms, lose electrons during oxidation.

Cellular Processes and Their Researchers:

  • Glycolysis: Discovered by Gustav Embden, Otto Meyerhof, Jacob Parnas.
  • Also known as Embden-Meyerhof-Parnas (EMP) pathway.
  • Tricarboxylic Acid Cycle: Discovered by Sir Hans Krebs.
  • Also called Krebs cycle.

Aerobic Respiration Process:

  • Energy Production: Aerobic respiration of carbohydrates, proteins, and fats.
 
  • Anaerobic Respiration: In living organisms/cells.

Energy Production in Microorganisms through Anaerobic Respiration:
  • Some bacteria and lower organisms cannot survive in the presence of oxygen.
  • They perform anaerobic respiration for energy.
  • Anaerobic respiration has two steps: Glycolysis and fermentation.
    • Glycolysis: Glucose incompletely oxidized, releasing less energy.
    • Fermentation: Pyruvic acid converted to organic acids or alcohol (C₂H₅OH).
  • Process: Aided by enzymes.
  • When oxygen levels are low:
  • Higher plants, animals, and aerobic microorganisms may also perform anaerobic respiration.
  • Examples:
    • Submerged Soil: Seeds undergo anaerobic respiration during germination.
    • Exercise: Human muscle cells switch to anaerobic respiration.
  • Result: Less energy released, lactic acid accumulation leads to fatigue.

Energy from Different Food Components:

Carbohydrates: Excess stored as glycogen in liver and muscles.

Proteins:

 

  • Structure: Formed by amino acids held by peptide bonds.
  • Digestion: Converted back to amino acids.
  • Absorption: Amino acids absorbed into blood, transported to cells.
  • First Class Proteins: Animal proteins.
  • Energy: 4 Kcal/g.
  • Excess Intake: Broken down into ammonia, eliminated from body.
  • Gluconeogenesis: Excess proteins converted to glucose.
  • Plants: Produce amino acids from minerals.

Lipids:

  • Components: Fatty acids and glycerol.
  • Digestion: Converted to fatty acids and glycerol.
  • Function: Produce various substances in cells.
  • Examples: Phospholipids (plasma membrane), hormones, nerve cell coverings.
  • Storage: Adipose tissue.
  • Energy: 9 Kcal/g.

Vitamins:

  • Function: Essential for body functioning and maintenance.
  • Types: Fat soluble (A, D, E, K), Water soluble (B, C).
  • Specific Functions: Riboflavin (Vitamin B2) - production of FADH2, Nicotinamide (Vitamin B5) - production of NADH2.

Water:

  • Essential Nutrient: Crucial for body function.
  • Body Composition: 66-70% water, 70% in every cell, 90% in blood plasma.
  • Importance: Dehydration affects cell and body function.

Cell Division: An Essential Life Process

Introduction:

  • After Injury: Cells and tissues can't function immediately.
  • Injury Response: Blood capillaries rupture, inflammation occurs, damaged cells.
  • Healing Process: Scab forms, surrounding cells divide rapidly to restore lost cells.
  • Plant Sensations: Recent discoveries show plants also regenerate lost tissues through cell division.

Growth of Living Organisms:

  • Cell Increase: Living organisms grow with an increase in cell number.
  • Regular Cell Division: New cells added regularly for growth.
  • Essential for Growth: Cell division necessary for body growth, tissue regeneration, and repair.

Reproduction:

  • Asexual Reproduction: Involves mitosis for forming new individuals.
  • Sexual Reproduction: Gametes formed by meiosis (reduction division), Chromosomes, genes, DNA ensure similarity with existing species.

Significance of Cell Division:

  • New Organism Formation: From existing one.
  • Growth of Multicellular Organisms: Essential for growth.
  • Tissue Restoration: Injured or emaciated body can be restored.

Types of Cell Division: 1. Mitosis & 2. Meiosis

(i) Mitosis:

Stages: Karyokinesis: Nuclear division, Cytokinesis: Cytoplasmic division.

Karyokinesis:

(a) Prophase:

  • Chromosome condensation starts.
  • Chromosomes thicken, seen as sister chromatid pairs.
  • Centrioles duplicate, move to opposite poles.
  • Nuclear membrane and nucleolus disappear.

(b) Metaphase:

  • Chromosomes condense fully.
  • Each with sister chromatids.
  • Align at equatorial plane.
  • Spindle fibers attach to centromeres.
  • Nuclear membrane disappears.

(c) Anaphase:

  • Centromeres divide.
  • Sister chromatids separate.
  • Pulled to opposite poles by spindle fibers.
  • Look like bunch of bananas.

(d) Telophase:

  • Reverse of prophase.
  • Chromosomes decondense.
  • Nuclear membrane and nucleolus reappear.
  • Spindle fibers lost.
  • Cell appears to have two nuclei.

Cytokinesis:

  • Notch develops in animal cell center.
  • Deepens, cytoplasm divides.
  • Plant cells: Cell plate forms, then divides.

 

Significance of Mitosis:

  • Growth of body.
  • Restoration of emaciated body.
  • Wound healing.
  • Blood cell formation.

(ii) Meiosis:

Stages: Meiosis I & Meiosis II

Meiosis I:

  • Diploid cell forms four haploid cells.
  • Crossing over occurs, genetic recombination.
  • Daughter cells not identical.
  • Forms spores and gametes.
  • Maintains chromosome number.

(a) Meiosis I:

  • Homologous chromosomes cross over.
  • Divided into two groups, form two haploid cells.
  • Prophase I subdivided into: Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis.
 
(b) Meiosis II:
  • Similar to mitotic division.
  • Haploid cells further divide, forming four haploid cells.
  • Diploid (2n) vs. haploid (n).
  • In '2n', chromosomes in pairs; in 'n', single chromosome of each type.
 

 Important Features of Mitosis and Meiosis: