Class 12 Biology Guess Paper 2026 Plus Solved Short Questions Notes of Important Questions
Chapter 15 (Homeostasis)
1. What is lithotripsy?
It is a medical procedure that uses shock waves to break kidney stones into smaller pieces so they can be passed out in urine.
2. What are pyrogens?
These are fever-causing substances, often released by bacteria or damaged tissues, that reset the body’s thermostat in the hypothalamus.
3. What is a hypertonic environment and what changes occur in a cell in such an environment?
A hypertonic environment has higher solute concentration outside the cell. Water moves out of the cell, causing it to shrink (crenation in animals; plasmolysis in plants).
4. What are osmo-conformers and osmoregulators?
Osmo-conformers match their internal osmolarity with the environment. Osmoregulators maintain constant internal osmolarity regardless of the environment.
5. What is extracorporeal shock wave lithotripsy?
It is a non-invasive treatment that uses shock waves generated outside the body to break kidney stones.
6. What are heat shock proteins?
These are proteins produced by cells in response to stressful conditions like high temperature; they help protect and repair other proteins.
7. What are flame cells? Give their role.
Flame cells are specialized excretory cells in flatworms. Their role is to filter waste from the body and move it into excretory ducts.
8. Write the structural formula of urea and uric acid.
Urea: \text{H}_2\text{N}-\text{CO}-\text{NH}_2
Uric acid: \text{C}_5\text{H}_4\text{N}_4\text{O}_3 (a bicyclic structure)
9. Define homeostasis. Give its importance.
Homeostasis is the maintenance of a stable internal environment despite external changes. It is important for optimal enzyme function and cell survival.
10. Define anhydrobiosis with an example.
It is a state of extreme dormancy where organisms lose almost all body water to survive desiccation. Example: Tardigrades (water bears).
11. Define countercurrent multiplier mechanism.
It is a process in the loop of Henle where fluid flows in opposite directions, creating an osmotic gradient that helps concentrate urine.
12. Differentiate between poikilotherms and homeotherms.
Poikilotherms have variable body temperature with the environment (e.g., fish). Homeotherms maintain constant body temperature (e.g., humans).
13. Differentiate between ectotherms and endotherms.
Ectotherms gain heat from the environment (e.g., reptiles). Endotherms generate heat internally through metabolism (e.g., birds, mammals).
14. Differentiate between shivering and non-shivering thermogenesis.
Shivering thermogenesis generates heat by rapid muscle contractions. Non-shivering thermogenesis produces heat through metabolic processes (e.g., brown fat).
15. Differentiate between hemodialysis and peritoneal dialysis.
Hemodialysis uses an artificial machine to filter blood. Peritoneal dialysis uses the patient’s peritoneum as a natural filter.
16. Differentiate between xerophytes and mesophytes.
Xerophytes live in dry conditions (e.g., cacti); mesophytes live in moderate water conditions (e.g., mango tree).
17. Draw and label urea cycle.
(Not possible in text; student should draw from textbook: ornithine → citrulline → argininosuccinate → arginine → urea + ornithine)
18. Explain the process of panting with an example.
Panting is rapid, shallow breathing to lose heat through evaporation. Example: Dogs panting on a hot day.
19. Illustrate the function of Malpighian tubules.
They are excretory structures in insects that remove nitrogenous wastes from hemolymph and empty them into the gut.
20. Why are leaves said to be excretophores?
Leaves collect and remove waste products like calcium oxalate; when leaves fall, waste is eliminated.
---
Chapter 16 (Support and Movement)
1. What is sciatica?
Pain along the sciatic nerve (from lower back down the leg), often due to a herniated disc.
2. What is foramen triosseum?
A three-bone opening in birds (scapula, coracoid, clavicle) through which the supracoracoideus tendon passes to lift the wing.
3. What is the role of vascular cambium?
It is a lateral meristem that produces secondary xylem and phloem, increasing stem and root thickness.
4. What is axial skeleton?
The part of the skeleton along the body’s midline: skull, vertebral column, ribs, sternum.
5. What are synovial joints?
Freely movable joints containing synovial fluid, e.g., knee, elbow.
6. What is meant by passive and active flight?
Active flight: powered by muscle contractions. Passive flight: gliding without flapping.
7. What is rickets? Give its causes and cure.
Bone softening in children due to vitamin D deficiency. Cure: vitamin D and calcium supplements.
8. What is herniation of discs?
Slipped disc where the inner gel of an intervertebral disc bulges out, pressing on nerves.
9. What is the difference between tetanus and muscle tetany?
Tetanus is a bacterial disease causing muscle spasms. Tetany is prolonged muscle contraction due to low blood calcium.
10. What are the sources of energy for muscle contraction?
ATP, creatine phosphate, and glycolysis (glucose breakdown).
11. What is the difference between exoskeleton and endoskeleton?
Exoskeleton is external (e.g., insects); endoskeleton is internal (e.g., humans).
12. What is hematoma formation?
Blood clotting at a fracture site, forming a mass that starts the healing process.
13. What is effective and recovery stroke?
In cilia/flagella: effective stroke (power stroke) moves the cell; recovery stroke returns the structure to original position.
14. What are plantigrade and unguligrade?
Plantigrade: walking with whole foot (e.g., humans). Unguligrade: walking on hooves (e.g., cows).
15. Characterize collenchyma cells.
Living cells with uneven thickened walls; provide support in young stems and leaves.
16. Compare phototropism and geotropism.
Phototropism is growth toward/away from light. Geotropism is growth toward/away from gravity.
17. Compare hinge joint with ball and socket joint.
Hinge: moves in one plane (e.g., elbow). Ball & socket: multi-directional movement (e.g., shoulder).
18. Discuss hematoma formation. (Same as Q12)
19. Define photonasty and thermonasty.
Photonasty: response to light/dark (e.g., flower opening). Thermonasty: response to temperature (e.g., tulip opening in warmth).
20. Define haptonastic movement.
Movement in response to touch (e.g., Venus flytrap closing).
21. Define antagonistic movement of muscles.
Opposing muscles working in pairs; one contracts while the other relaxes (e.g., biceps and triceps).
22. Define ecdysis.
Molting or shedding of the outer cuticle in arthropods and reptiles.
23. Discuss two main types of cartilage.
Hyaline cartilage (smooth, ends of bones) and fibrocartilage (tough, intervertebral discs).
24. Differentiate between sclerenchyma and collenchyma.
Sclerenchyma: thick, lignified, dead cells (support). Collenchyma: uneven walls, living cells (flexible support).
25. Differentiate between fibers and sclereids.
Fibers: long, narrow, in bundles. Sclereids: short, irregular, in seed coats and fruit walls.
26. Differentiate between compact bone and spongy bone.
Compact: dense, outer layer. Spongy: porous, inner layer with red marrow.
27. Distinguish between axial skeleton and appendicular skeleton.
Axial: skull, spine, ribs. Appendicular: limbs and girdles.
28. Differentiate between skeletal and smooth muscles.
Skeletal: voluntary, striated. Smooth: involuntary, non-striated.
29. Differentiate between Osteoporosis and Osteomalacia.
Osteoporosis: low bone mass, porous bones. Osteomalacia: soft bones due to poor mineralization.
30. Distinguish between phototactic and chemotactic movements.
Phototaxis: movement toward/away from light. Chemotaxis: movement toward/away from chemicals.
31. Differentiate between brachialis and brachioradialis.
Brachialis: elbow flexor under biceps. Brachioradialis: forearm muscle that also flexes elbow.
32. Differentiate between origin and insertion of muscle.
Origin: fixed attachment. Insertion: movable attachment.
33. Differentiate between bone and cartilage.
Bone: hard, vascular, calcified. Cartilage: flexible, avascular, not calcified.
34. Differentiate between troponin and tropomyosin.
Troponin: binds calcium, initiates contraction. Tropomyosin: blocks myosin-binding sites on actin.
35. Differentiate between heartwood and sapwood.
Heartwood: dark, dead, non-conducting. Sapwood: light, living, conducts water.
36. Differentiate between vessel and tracheids.
Vessels: short, wide, perforated ends. Tracheids: long, narrow, tapered ends.
37. Differentiate between ligament and tendon.
Ligament: bone to bone. Tendon: muscle to bone.
38. Explain two types of nastic movements.
Epinasty: downward bending (e.g., leaf droop). Hyponasty: upward bending.
39. Enlist some functions of skeleton.
Support, protection, movement, mineral storage, blood cell production.
40. How is callus formed?
Formed by dividing cells (cambium) at a fracture or cut site during healing.
41. Name the different types of cells associated with bones.
Osteoblasts, osteocytes, osteoclasts, osteoprogenitor cells.
Chapter 17 (Coordination & Control)
1. What is innate behavior?
Inborn, inherited behavior not learned (e.g., baby sucking).
2. What is the role of hypothalamus?
Controls homeostasis, temperature, thirst, hunger, and pituitary gland.
3. What is synapse?
The gap between two neurons where neurotransmitters transmit signals.
4. What is habituation? Give an example.
Decreased response to repeated harmless stimulus. Example: Ignoring background noise.
5. What is the role of thyroxine?
Regulates metabolic rate, growth, and development.
6. What is the role of vasopressin/ADH and oxytocin?
ADH: increases water reabsorption in kidneys. Oxytocin: stimulates uterine contractions and milk release.
7. What is the function of estrogen and progesterone?
Estrogen: female secondary sex characteristics. Progesterone: maintains pregnancy.
8. What is the commercial application of cytokinins?
Used in tissue culture to promote cell division and delay leaf senescence.
9. What are androgens?
Male sex hormones (e.g., testosterone).
10. What are sensory neurons?
Neurons that carry impulses from receptors to the central nervous system.
11. What are axons and dendrites?
Axon: carries impulse away from cell body. Dendrites: carry impulse toward cell body.
12. What is reflex arc?
The neural pathway of a reflex action, from receptor to effector.
13. What are the symptoms of Alzheimer's disease?
Memory loss, confusion, personality changes, difficulty speaking.
14. What is the difference between CNS and PNS?
CNS: brain and spinal cord. PNS: nerves outside CNS.
15. What is the function of parathyroid gland or parathormone?
Increases blood calcium by releasing calcium from bones.
16. What is Parkinson's disease?
A movement disorder due to dopamine deficiency; symptoms include tremors and rigidity.
17. What is neuroglia?
Supporting cells of the nervous system that nourish and protect neurons.
18. What are Nissl's granules?
Rough ER in neurons; site of protein synthesis.
19. What are gastrin and secretin?
Gastrin: stimulates gastric juice secretion. Secretin: stimulates pancreatic juice and bile release.
20. Write the function of photoreceptors and nociceptors.
Photoreceptors: detect light. Nociceptors: detect pain.
21. Compare Circadian and Circannual rhythms.
Circadian: daily cycles (sleep-wake). Circannual: yearly cycles (migration, hibernation).
22. Define saltatory impulse.
Rapid impulse conduction in myelinated neurons where signal jumps between Nodes of Ranvier.
23. Define the term hormone, give one example.
A chemical messenger from endocrine glands. Example: Insulin.
24. Define feedback mechanism.
A system where output regulates input (positive or negative feedback).
25. Differentiate between biorhythms and diurnal rhythms.
Biorhythms: any biological cycle. Diurnal rhythms: specifically daily cycles.
26. Differentiate between etiolation and chlorosis.
Etiolation: pale, elongated growth in darkness. Chlorosis: yellowing due to lack of chlorophyll.
27. Differentiate between callus and galls.
Callus: undifferentiated plant cells from wounding. Galls: abnormal growths due to insects/pathogens.
28. Differentiate between sympathetic and parasympathetic nervous system.
Sympathetic: fight or flight. Parasympathetic: rest and digest.
29. Differentiate between active and resting membrane potential.
Resting: -70 mV (inside negative). Active: +30 mV (depolarized during impulse).
30. Give the role of 2,4-Dichlorophenoxyacetic Acid.
Synthetic auxin used as a herbicide.
31. Give two commercial applications of Gibberellins.
Increase fruit size (grapes) and speed up seed germination.
32. Name and define different types of tropisms.
Phototropism (light), geotropism (gravity), hydrotropism (water), thigmotropism (touch).
33. Give effects of nicotine on blood vascular system and digestive system.
Increases heart rate and blood pressure; reduces appetite and causes nausea.
34. Explain the functions of insulin and glucagon.
Insulin: lowers blood glucose. Glucagon: raises blood glucose.
35. Explain imprinting.
Rapid, early learning that is irreversible (e.g., duckling following mother).
---
Chapter 18 (Reproduction)
1. What is follicle atresia?
Degeneration of ovarian follicles that do not mature.
2. What is after birth?
Expulsion of the placenta after delivery of the baby.
3. What is the role of placenta in human?
Exchange of gases, nutrients, wastes; produces hormones.
4. What is seed dormancy? Give its importance.
Inability of a viable seed to germinate under favorable conditions. Importance: allows survival through adverse conditions.
5. What is the role of interstitial cells in sperm production?
They produce testosterone, which supports spermatogenesis.
6. What is the structure and function of corpus luteum?
Remnant of follicle after ovulation; secretes progesterone to maintain pregnancy.
7. What is parthenocarpy?
Fruit development without fertilization (e.g., banana).
8. Write down at least two important measures to prevent AIDS.
Use condoms; avoid sharing needles.
9. What are Oviparous, Viviparous and Ovoviviparous animals?
Oviparous: lay eggs. Viviparous: give birth to live young. Ovoviviparous: eggs hatch inside mother.
10. Classify plants according to photoperiodic requirement for flowering.
Short-day plants, long-day plants, day-neutral plants.
11. Compare sexual and asexual reproduction.
Sexual: two parents, genetic variation. Asexual: one parent, clones.
12. Define photoperiodism and write its effects in plants.
Response to day length; affects flowering, dormancy, tuber formation.
13. Define apomixis.
Production of seeds without fertilization (asexual reproduction in plants).
14. Define vernalization.
Induction of flowering by exposure to cold temperatures.
15. Differentiate between haploid parthenogenesis and diploid parthenogenesis.
Haploid: egg develops into haploid individual. Diploid: egg develops after chromosome doubling.
16. Differentiate between menopause and ovulation.
Menopause: end of menstrual cycles. Ovulation: release of an egg.
17. Differentiate between internal and external fertilization.
Internal: inside female body. External: outside (e.g., fish).
18. Differentiate between spermatogenesis and oogenesis.
Spermatogenesis: produces 4 sperm. Oogenesis: produces 1 egg + polar bodies.
19. Differentiate between identical twins and fraternal twins.
Identical: one egg, one sperm, split. Fraternal: two eggs, two sperm.
20. How can you differentiate between menstrual cycle and oestrous cycle?
Menstrual: uterine lining sheds (humans). Oestrous: reabsorbed if no pregnancy (dogs).
21. How does lactation differ from gestation?
Lactation: milk production. Gestation: pregnancy period.
22. How are test tube babies produced?
Egg fertilized with sperm outside the body (IVF), then implanted into uterus.
---
Chapter 20 (Chromosomes & DNA)
1. What is semi-conservative replication of DNA?
Each new DNA molecule has one old strand and one new strand.
2. What is sickle cell anemia?
Genetic disorder caused by a point mutation in hemoglobin gene; RBCs become sickle-shaped.
3. What is transformation?
Uptake of free DNA by bacteria from the environment.
4. What is translation?
Protein synthesis from mRNA at the ribosome.
5. What are mutagens? Give one example.
Agents that cause mutations. Example: UV radiation.
6. What are the contributions of P.A. Levene?
Discovered that DNA contains phosphate, sugar (deoxyribose), and four bases.
7. What is alkaptonuria?
Genetic disorder where homogentisic acid accumulates in urine (turns black on exposure).
8. What is central dogma?
DNA → RNA → Protein.
9. What is genetic code?
Triplet codons in mRNA that specify amino acids.
10. Where are codon and anticodon situated?
Codon: on mRNA. Anticodon: on tRNA.
11. What is heterochromatin?
Tightly packed, inactive DNA.
12. What is mutation?
Change in DNA sequence.
13. What is phosphodiester linkage?
Bond between phosphate group and sugar in DNA backbone.
14. Compare replication, transcription and translation.
Replication: DNA→DNA. Transcription: DNA→RNA. Translation: RNA→Protein.
15. Define chromosomal theory of inheritance.
Genes are located on chromosomes.
16. Define karyotype.
Complete set of chromosomes in a cell.
17. Define nucleosome.
DNA wrapped around histone proteins.
18. Define nucleotide and nucleoside.
Nucleotide: sugar + base + phosphate. Nucleoside: sugar + base.
19. Define one gene/one polypeptide hypothesis.
Each gene codes for one polypeptide chain.
20. Define point mutation.
Change in a single nucleotide.
21. Define transcription.
Synthesis of RNA from DNA template.
22. Differentiate among conservative, semi-conservative, and dispersive replication.
Conservative: original intact. Semi-conservative: mixed. Dispersive: fragments.
23. Differentiate between leading and lagging strand.
Leading: continuous synthesis. Lagging: discontinuous (Okazaki fragments).
24. Differentiate between sense and antisense strands of DNA.
Sense: coding strand (same as mRNA except T→U). Antisense: template strand.
25. Differentiate between rough and smooth type of bacteria.
Rough: no capsule, non-virulent. Smooth: capsule, virulent.
26. Enlist different shapes of chromosomes.
Metacentric, submetacentric, acrocentric, telocentric.
27. What are Okazaki fragments?
Short DNA fragments on the lagging strand.
28. Give the role and kinds of tRNA.
Brings amino acids to ribosomes. Types: initiator, elongator.
29. How many types of DNA polymerases are found?
Three in prokaryotes: DNA pol I, II, III.
Here are the remaining short questions from Chapters 21 to 27, answered in the same easy but standard format.
---
Chapter 21 (Cell Cycle)
1. What is necrosis?
Uncontrolled, premature cell death due to injury or infection, causing inflammation.
2. What is a tumor?
Abnormal mass of tissue formed by uncontrolled cell division.
3. What is Klinefelter's syndrome?
A genetic disorder in males with XXY chromosomes; causes small testes and infertility.
4. What is metastasis?
Spread of cancer cells from original site to other body parts.
5. What is the importance of bivalent formation?
Bivalent (paired homologous chromosomes) allows crossing over during meiosis I.
6. What happens during metaphase I?
Bivalents align at the equator; spindle fibers attach to centromeres.
7. What are the symptoms of Down's syndrome?
Mental retardation, flat face, short stature, protruding tongue.
8. What are the symptoms of Turner's syndrome?
Female with XO chromosomes; short stature, webbed neck, underdeveloped ovaries.
9. What is apoptosis?
Programmed, controlled cell death; no inflammation.
10. What is mitotic apparatus?
Structure consisting of spindle fibers and centrioles that separates chromosomes.
11. Define cell cycle.
Series of events from one cell division to the next (interphase + mitotic phase).
12. Define non-disjunction.
Failure of homologous chromosomes or sister chromatids to separate during meiosis.
13. Define karyokinesis and cytokinesis.
Karyokinesis: division of nucleus. Cytokinesis: division of cytoplasm.
14. Define meiosis and mitosis.
Mitosis: one division, two identical diploid cells. Meiosis: two divisions, four haploid cells.
15. Differentiate between benign and malignant tumor.
Benign: non-cancerous, does not spread. Malignant: cancerous, invades other tissues.
16. Differentiate between G₀-phase and S-phase.
G₀: resting phase, no DNA synthesis. S-phase: DNA replication occurs.
17. Give events of zygotene.
Pairing of homologous chromosomes (synapsis) forming bivalents.
18. Give two main importance of meiosis.
Gamete formation and genetic variation.
19. How can you identify cancer cells?
They divide uncontrollably, have abnormal shape, and invade other tissues.
20. How does mitosis in plant cells differ from animal cells?
Plants lack centrioles; form a cell plate instead of a cleavage furrow.
21. Sketch and label cell cycle.
(Not possible in text; draw interphase (G1, S, G2) and M-phase.)
---
Chapter 22 (Variation & Genetics)
1. What is Bombay phenotype?
A rare blood type where person lacks H-antigen, so blood appears as type O even if genes for A/B present.
2. What is MODY?
Maturity Onset Diabetes of the Young – a monogenic form of diabetes.
3. What is SRY gene? How is it transferred?
Sex-determining region on Y chromosome; transferred from father to son.
4. What are genes and alleles?
Gene: unit of heredity. Allele: alternate form of a gene.
5. What is a nullo gamete?
Gamete with no sex chromosome.
6. What do you know about hypophosphatemic rickets?
X-linked dominant disorder; kidneys excrete too much phosphate.
7. What is testicular feminization syndrome?
Genetic male (XY) with female appearance due to androgen insensitivity.
8. What are pseudoautosomal genes?
Genes on sex chromosomes that behave like autosomes (pair during meiosis).
9. What is hemophilia?
Blood clotting disorder (X-linked recessive).
10. What is the role of blood groups in establishing parentage?
Blood groups can exclude paternity but cannot prove it definitively.
11. What is meant by universal blood donor and universal recipient?
Donor: O negative. Recipient: AB positive.
12. What are X-linked and Y-linked genes?
X-linked: on X chromosome (e.g., hemophilia). Y-linked: on Y (e.g., SRY).
13. What is crossing over? Its importance?
Exchange of segments between homologous chromosomes; creates genetic variation.
14. What is a gene pool?
All genes and alleles present in a population.
15. What is erythroblastosis fetalis?
Condition where Rh⁺ baby's RBCs are attacked by Rh⁻ mother's antibodies.
16. What is linkage and linkage group?
Linkage: genes on same chromosome inherited together. Linkage group: all genes on one chromosome.
17. What is test cross?
Crossing an unknown dominant phenotype with a homozygous recessive to determine genotype.
18. Differentiate between heterogametic and homogametic.
Heterogametic: two different sex chromosomes (e.g., XY male). Homogametic: same (XX female).
19. What are compound sex chromosomes?
Sex chromosomes fused or rearranged (e.g., XXY, XO).
20. Compare monohybrids with dihybrids.
Monohybrid: one trait. Dihybrid: two traits.
21. Define Mendel's law of segregation.
Alleles separate during gamete formation.
22. Differentiate between phenotype and genotype.
Phenotype: observable trait. Genotype: genetic makeup.
23. Differentiate between incomplete dominance and co-dominance.
Incomplete: blending (red+white=pink). Co-dominance: both expressed (AB blood type).
24. Differentiate between autosomes and sex chromosomes.
Autosomes: non-sex chromosomes. Sex chromosomes: determine sex.
25. Differentiate between gene and genome.
Gene: single unit. Genome: all DNA in a cell.
26. Differentiate between homozygous and hemizygous.
Homozygous: same alleles. Hemizygous: one allele (males for X-linked genes).
27. Differentiate between homozygous and heterozygous.
Homozygous: same alleles. Heterozygous: different alleles.
28. Differentiate between dominant and recessive trait.
Dominant: expressed in heterozygote. Recessive: only in homozygote.
29. Differentiate between qualitative and quantitative traits.
Qualitative: few categories (e.g., flower color). Quantitative: continuous variation (e.g., height).
30. Differentiate between X-linked and Y-linked traits.
X-linked: on X (e.g., color blindness). Y-linked: on Y (e.g., hairy ears).
31. Differentiate between X-linked dominant and X-linked recessive.
Dominant: appears in both sexes. Recessive: more common in males.
32. Differentiate between IDDM and NIDDM.
IDDM: Type 1, insulin-dependent. NIDDM: Type 2, non-insulin-dependent.
33. Differentiate between multifactorial and polygenic traits.
Multifactorial: genes + environment. Polygenic: multiple genes only.
34. Differentiate between probability and product rule.
Probability: chance of one event. Product rule: chance of two independent events.
35. Differentiate between protanopia, deuteranopia, tritanopia.
Protanopia: red-blind. Deuteranopia: green-blind. Tritanopia: blue-blind.
36. Differentiate between allele and multiple alleles.
Allele: one form of a gene. Multiple alleles: more than two alleles in population (e.g., ABO).
37. Differentiate between dominance and epistasis.
Dominance: one allele masks another at same locus. Epistasis: one gene masks another at different locus.
38. Differentiate between sex-limited and sex-influenced traits.
Sex-limited: only one sex (e.g., milk production). Sex-influenced: both sexes but different expression (e.g., beard in goats).
39. Distinguish between polygenes and pleiotropy.
Polygenes: multiple genes affect one trait. Pleiotropy: one gene affects multiple traits.
40. Give the concept of fixed allele.
All individuals in population have same allele for that gene (frequency = 1).
41. How is sex determination in yeast?
By mating types (a and α), not by X/Y chromosomes.
42. Find recombination frequency (given: parental 40+40=80, recombinant 10+10=20).
Recombination frequency = (20/100) × 100 = 20%.
---
Chapter 23 (Biotechnology)
1. What is a probe?
A labeled single-stranded DNA/RNA used to detect complementary sequences.
2. What is gene pharming?
Use of transgenic animals/plants to produce pharmaceutical proteins.
3. What is aspartame?
An artificial sweetener made from two amino acids.
4. What is gene therapy?
Inserting functional genes into a patient's cells to treat genetic disorders.
5. What is cystic fibrosis?
Genetic disorder affecting lungs and digestive system due to defective CFTR gene.
6. What are clonal plants?
Genetically identical plants produced by vegetative propagation.
7. What is meant by cloning?
Producing genetically identical copies of an organism or DNA.
8. What are palindromic sequences?
DNA sequences that read same forward and backward (e.g., GAATTC).
9. What are methods of gene sequencing?
Sanger method (chain termination) and next-generation sequencing.
10. What are the two goals of Human Genome Project?
Map all human genes and determine complete DNA sequence.
11. What is biodegradable plastic and its origin?
Plastic broken down by microbes; made from plant starch or bacterial PHB.
12. What is SCID?
Severe Combined Immunodeficiency – lack of functional immune system.
13. What is the role of suicide gene in transgenic bacteria?
Kills bacteria under specific conditions to prevent environmental release.
14. What is the advantage of genetic engineering of C4 plants?
Higher photosynthetic efficiency and better water use.
15. What are transgenic plants?
Plants with foreign DNA; advantage: pest resistance, better yield.
16. What is ex-vivo gene therapy?
Cells removed, genetically modified, then returned to body.
17. What is a genome and genomic library?
Genome: all DNA. Genomic library: collection of DNA fragments representing entire genome.
18. What is PCR and its applications?
Polymerase Chain Reaction amplifies DNA. Uses: DNA fingerprinting, disease diagnosis.
19. What is totipotency?
Ability of a single cell to develop into a complete organism.
20. Define biotechnology. Give its application.
Use of living organisms to make useful products. Application: insulin production.
21. Define molecular scissors.
Restriction enzymes that cut DNA at specific sequences.
22. What is the role of a molecular carrier (vector)?
Carries foreign DNA into host cell (e.g., plasmid).
23. Explain the importance of gene sequencing.
Helps understand gene function, diagnose diseases, and develop treatments.
---
Chapter 24 (Evolution)
1. What is genetic drift?
Random change in allele frequencies in a small population.
2. What are hydrothermal vents?
Deep-sea openings that release hot mineral-rich water; support unique ecosystems.
3. What is modern synthesis/Neo-Darwinism?
Combines Darwinian natural selection with Mendelian genetics.
4. Name theories of evolution by Lamarck and Darwin.
Lamarck: inheritance of acquired characteristics. Darwin: natural selection.
5. What are vestigial organs? Name some in man.
Non-functional organs. Examples: appendix, tailbone, wisdom teeth.
6. Define Neo-Darwinism. (Same as Q3)
7. Define fossil. Where are most fossils found?
Remains of ancient life. Most found in sedimentary rocks.
8. Define endosymbiont hypothesis.
Eukaryotes evolved from prokaryotes living inside each other (mitochondria, chloroplasts).
9. Define endangered species.
Species at high risk of extinction (e.g., snow leopard).
10. Define Hardy-Weinberg Theorem.
Allele frequencies remain constant in a population without evolutionary influences. Equation: p² + 2pq + q² = 1.
11. Differentiate between homology and analogy.
Homology: same origin, different function. Analogy: different origin, same function.
12. Differentiate between homologous and analogous organs.
Homologous: human arm and bird wing. Analogous: bird wing and insect wing.
13. Name four factors affecting gene frequency.
Mutation, natural selection, genetic drift, gene flow.
14. Define theory of special creation.
All species created separately by a divine being.
---
Chapter 25 (Ecosystems)
1. What is ammonification?
Decomposition of organic nitrogen into ammonia by bacteria.
2. What are root nodules?
Swelling on legume roots containing nitrogen-fixing bacteria (Rhizobium).
3. What is assimilation?
Uptake and use of nutrients by organisms.
4. What is mycorrhiza?
Fungal association with plant roots; helps nutrient absorption.
5. What are lichens?
Symbiotic association between fungus and alga.
6. What is grazing? Effect on soil?
Animals eating grass; can compact soil and reduce plant cover.
7. What is a biome?
Large geographical area with similar climate and organisms.
8. Write briefly about secondary succession.
Ecological succession on land that previously had vegetation (e.g., after a fire).
9. Define predation.
One organism kills and eats another.
10. Define succession and name its types.
Gradual change in community over time. Types: primary and secondary.
11. Define biogeochemical cycles.
Recycling of nutrients between living and non-living components.
12. Define productivity. Differentiate between GPP and NPP.
GPP: total photosynthesis. NPP: GPP minus respiration.
13. Define ecosystem. Its components.
Community + environment. Components: biotic and abiotic.
14. Define biosphere.
Global sum of all ecosystems.
15. Define biotic components.
Living parts of an ecosystem (producers, consumers, decomposers).
16. Define parasitism.
One organism benefits at the expense of another host.
17. Define commensalism. Example.
One benefits, other unaffected. Example: barnacles on whale.
18. Define food chain and food web.
Food chain: linear energy flow. Food web: interconnected food chains.
19. Differentiate between population and community.
Population: same species. Community: different species in an area.
20. Differentiate between habitat and niche.
Habitat: where an organism lives. Niche: its role and interactions.
21. Differentiate between autecology and synecology.
Autecology: study of one species. Synecology: study of multiple species.
22. Differentiate between micro and macro nutrients.
Micro: needed in small amounts (e.g., iron). Macro: needed in large amounts (e.g., nitrogen).
23. Differentiate between consumers and decomposers.
Consumers: eat others. Decomposers: break down dead matter.
24. Differentiate between hydroser and xerosere.
Hydroser: succession in water. Xerosere: succession on dry rock/sand.
25. Differentiate between primary and secondary succession.
Primary: no soil. Secondary: soil present.
26. Name ways of nitrogen depletion and remedy.
Depletion: leaching, erosion. Remedy: crop rotation, fertilizers.
---
Chapter 27 (Pollution & Conservation)
1. What is acid rain?
Rain with pH below 5.6 due to SO₂ and NOâ‚“ from burning fossil fuels.
2. What is eutrophication?
Excess nutrients in water cause algal bloom, then oxygen depletion.
3. What is ozone? Importance of ozone layer?
Ozone (O₃) absorbs harmful UV radiation.
4. What are pollutants?
Substances that harm the environment.
5. Write names of types of pollution.
Air, water, land, noise, radioactive.
6. What are main sources of water pollution?
Sewage, industrial waste, agricultural runoff.
7. Write causes and effects of ozone depletion.
Causes: CFCs. Effects: skin cancer, cataracts, reduced crop yield.
8. What are solid wastes and how can they be energy sources?
Garbage; burned to produce electricity or converted to biogas.
9. Differentiate between renewable and non-renewable resources.
Renewable: solar, wind (replenish). Non-renewable: coal, oil (finite).
10. How can we save energy?
Use LED bulbs, turn off unused appliances, carpool, insulate homes.
11. What is deforestation?
Clearing of forests for other land use.
12. Define greenhouse effect.
Trapping of heat by greenhouse gases (CO₂, methane) in the atmosphere.
13. Describe abuses of land.
Overgrazing, deforestation, soil erosion, desertification.
14. Define soil and its basic constituents.
Upper layer of earth; minerals, organic matter, water, air.
15. Differentiate between health and disease.
Health: state of well-being. Disease: abnormality causing dysfunction.
16. Discuss importance of forests.
Oxygen production, climate regulation, habitat, soil conservation.
17. Differentiate between population explosion and population pressure.
Explosion: rapid growth. Pressure: strain on resources due to overpopulation.
18. How is air important to life?
Provides oxygen, CO₂ for plants, and protects from radiation.
19. Give uses and misuses of agrochemicals.
Uses: increase crop yield. Misuses: water pollution, health hazards.
20. Name two pathogenic and two congenital diseases.
Pathogenic: TB, malaria. Congenital: Down syndrome, hemophilia.
21. Why are trees called environmental buffers?
They reduce pollution, control temperature, prevent erosion, and moderate climate.
Good Luck 😊
Al-Suffah Science Academy
Jameel Town Campus G.M. Abad Faisalabad
0306-7107575
