bio

UNIT 1: GENETICS & BIOTECHNOLOGY

1.1 Mendelian & Non-Mendelian Inheritance

• Gene: A segment of DNA coding for a protein/trait.

• Alleles: Alternate forms of a gene (e.g., B vs. b for eye color).

• Dominant allele: Expressed if present (B).

• Recessive allele: Only expressed if homozygous (bb).

• Homozygous: Two identical alleles (BB or bb).

• Heterozygous: Two different alleles (Bb).

• Genotype: Allele combination (BB, Bb, bb).

• Phenotype: Observable traits (e.g., brown or blue eyes).

Non-Mendelian Patterns

• Incomplete Dominance: Heterozygous genotype results in blended phenotype (e.g., red + white = pink flowers).

• Codominance: Both alleles are fully expressed (e.g., AB blood type).

• Polygenic Inheritance: Traits controlled by multiple genes (e.g., height, skin color) – show continuous variation.

• Multiple Alleles: More than two alleles for a gene (e.g., ABO blood groups: IA, IB, i).

1.2 DNA Structure & Replication

• DNA (deoxyribonucleic acid): Double-helix structure made of nucleotides.

  • Nucleotides: Phosphate group, deoxyribose sugar, nitrogenous base (A, T, C, G).

  • Base pairing: A–T, C–G (complementary base pairing).

• DNA Replication:

  • Semi-conservative (each new strand has one original + one new strand).

  • Involves enzymes like DNA helicase and DNA polymerase.

1.3 Protein Synthesis

• Transcription (in nucleus):

  • DNA is transcribed into mRNA.

  • RNA bases: A–U (instead of T), C–G.

• Translation (in cytoplasm/ribosome):

  • mRNA codons (3-base sequences) are translated into amino acids by tRNA.

  • Amino acids link to form polypeptides → functional proteins.

1.4 Mutations

• Types: Substitution, insertion, deletion.

• Effects:

  • Silent (no change in protein),

  • Missense (changes amino acid),

  • Nonsense (premature stop).

• Causes: Radiation, chemicals, viruses.

1.5 Biotechnology & Genetic Engineering

• Recombinant DNA: Inserting a gene from one organism into another.

• Examples: Insulin production, GMO crops.

• Cloning: Producing identical copies of cells/organisms.

• PCR (Polymerase Chain Reaction): Amplifies DNA sequences.

• Ethical Issues: Gene editing (CRISPR), designer babies, GMOs, cloning.

UNIT 2: CARDIOVASCULAR SYSTEM

2.1 Heart Anatomy & Function

• Heart Chambers:

  • Right atrium: receives deoxygenated blood from body via vena cava.

  • Right ventricle: pumps blood to lungs via pulmonary artery.

  • Left atrium: receives oxygenated blood from lungs.

  • Left ventricle: pumps oxygenated blood to body via aorta.

• Valves: Tricuspid, bicuspid/mitral, pulmonary, aortic – ensure one-way flow.

2.2 Circulation Pathways

• Pulmonary Circulation: Right side of heart → lungs → left atrium.

• Systemic Circulation: Left side of heart → body tissues → right atrium.

• Coronary Circulation: Supplies heart muscle with blood.

2.3 Blood Vessels

• Arteries: Thick-walled, carry blood away from heart, high pressure.

• Veins: Thinner walls, valves, carry blood to heart, low pressure.

• Capillaries: One-cell thick; site of gas/nutrient/waste exchange.

2.4 Blood Components

• Red Blood Cells (Erythrocytes): Carry oxygen via hemoglobin.

• White Blood Cells (Leukocytes): Immune response.

• Platelets (Thrombocytes): Blood clotting.

• Plasma: Liquid matrix carrying cells, nutrients, hormones.

2.5 Blood Pressure & Heart Rate

• Systolic Pressure: Pressure during ventricular contraction.

• Diastolic Pressure: Pressure during relaxation.

• Normal BP: ~120/80 mmHg.

• Heart Rate: Controlled by medulla oblongata, affected by stress, hormones, fitness.

2.6 Cardiovascular Health

• Atherosclerosis: Buildup of plaque in arteries.

• Hypertension: High blood pressure.

• Heart attack: Blocked coronary artery.

• Lifestyle factors: Exercise, diet, smoking, alcohol use.

UNIT 3: IMMUNE SYSTEM

3.1 Lines of Defense

• First Line: Non-specific barriers (skin, tears, saliva, mucus, stomach acid).

• Second Line: Non-specific internal defenses:

  • Phagocytes: Engulf pathogens.

  • Inflammation: Increased blood flow, heat, swelling to isolate damage.

  • Fever: Raises body temp to slow pathogens.

3.2 Specific (Adaptive) Immunity

• Third Line:

  • B cells (humoral immunity):

    • Produce antibodies to neutralize antigens.

    • Memory B cells provide long-term immunity.

  • T cells (cell-mediated immunity):

    • Helper T cells: Activate B and T cells.

    • Killer T cells: Destroy infected cells.

    • Suppressor T cells: Regulate immune response.

3.3 Antibodies & Antigens

• Antigen: Foreign substance triggering immune response.

• Antibody: Protein produced by B cells to bind specific antigens.

3.4 Immunity Types

• Active Immunity:

  • Natural (exposure to disease) or artificial (vaccination).

• Passive Immunity:

  • Temporary; from external source (e.g., maternal antibodies, antibody injection).

3.5 Vaccination

• Introduces weakened/dead pathogens to stimulate immune memory.

• Creates quicker, stronger response upon re-exposure.

3.6 Immune Disorders

• Autoimmune diseases: Immune system attacks body (e.g., MS, lupus).

• Allergies: Overreaction to non-harmful substances.

• Immunodeficiency: Weakened response (e.g., HIV/AIDS destroys helper T cells).