NEET WEEKLY TEST BIOLOGY (29.11.2025)

1. In human RBCs, the component that not only forms the major structural framework of the plasma membrane but also anchors membrane enzymes and transport channels is:

2. A chromosome in a karyotype shows one arm that is extremely short due to the centromere being positioned just slightly away from the terminal region. This chromosome often possesses satellites attached by a secondary constriction. Such a centromere position is characteristic of which chromosome type?

3. Gas vacuoles in cyanobacteria are composed of gas-permeable protein shells that exclude water. What key function do these structures perform?

1) Store carbon dioxide for assimilation
2) Control their buoyancy
3) Provide anaerobic conditions to nitrogenase
4) Eliminate toxic ammonia

4. Microbodies, which help to convert stored lipids into carbohydrates so they can be used for plant growth, are known as:

1) Peroxisomes
2) Sphaerosomes
3) Glyoxysomes
4) Lysosomes

5. Proteins containing an N-terminal signal peptide are directed to ribosomes bound to a specific organelle, where co-translational translocation allows their entry into the endomembrane system for eventual secretion outside the cell. These proteins are synthesized:

1) In the mitochondrial matrix
2) On ribosomes attached to the rough ER
3) On smooth ER membranes
4) On free cytosolic ribosomes

6. In the given diagram of chloroplast, enzymes required for the synthesis of carbohydrates and proteins are located in:

1) A
2) B
3) C
4) D

7. The solid linear cytoskeleteal elements having a diameter of 6nm and made up of a single type of monomer are known as

1) Microtubles      
2) Microfilaments
3) Intermidiate filaments
4) lamins

8. The process in which a cell forms tiny vesicles to internalize extracellular fluid along with dissolved solutes often mediated by invagination of the plasma membrane and not requiring recognition of specific particles is termed:

1) Endocytosis
2) Exocytosis
3) Phagocytosis
4) Pinocytosis

9. Identify the correct statement regarding the part of a cell, the structure of which is shown in the given diagram:


1) It is not found in the plant cells
2) It serves to provide an attachment with a surface for a bacterial cell.
3) The structure is made of a protein called flagellin.
4) It can be used for movement by a eukaryotic cell.

10. Mitochondria and chloroplast are
I. semi-autonomous organelles.
II. formed by division of pre-existing organelles and they contain DNA but lack protein synthesizing machinery.
Which one of the following options is correct?

1) II is true but I is false
2) I is true but II is false
3) Both I and I are false
4) Both I and II are correct

11. During a Gram-staining procedure, a student observes that certain bacteria appear colorless immediately after the alcohol wash but turn red only after the counterstain is applied. Which of the following statements about these bacteria is incorrect?

1) They initially bind crystal violet but cannot retain it after decolorization
2) Their thin peptidoglycan layer makes them susceptible to alcohol-induced dye loss
3) They remain purple throughout the staining process due to thick peptidoglycan
4) They take up the safranin counterstain and appear pink/red at the end

12. In cold-adapted animals, the plasma membrane does not solidify easily even when the environmental temperature drops drastically. Which property of cholesterol MOST directly contributes to this phenomenon?

1) It wedges between phospholipid tails, preventing tight packing at low temperatures
2) It donates hydrogen atoms to unsaturated fatty acids, increasing membrane stability
3) It removes hydrogen atoms from saturated fatty acids, increasing membrane fluidity
4) It binds to phospholipid heads, making the membrane rigid under thermal stress

13. Although eubacteria differ greatly from eukaryotic cells, one of their cellular structures shares a highly similar biochemical organization and functional properties with that of eukaryotes, including involvement in selective transport and maintenance of membrane potential. This structure is:

1) Nucleus
2) Ribosomes
3) Cell wall
4) Plasma membrane

14. Plant cells exchange signaling molecules and metabolites through microscopic cytoplasmic bridges that traverse the cell wall and connect the symplast of adjacent cells. These channels serve as a direct pathway for intercellular transport. They are called:

1) Plasmalemma
2) Plastoquinones
3) Plasmodesmata
4) Endoplasmic reticulum

15. In an actively secreting animal cell, the majority of newly synthesized proteins destined for export, membrane insertion, or lysosomal packaging originate from ribosomes associated with a specific cellular location. These ribosomes are found:

1) Exclusively floating freely in the cytosol
2) Attached to the outer surface of the nuclear envelope and rough endoplasmic reticulum
3) Only in the mitochondria and cytosol
4) Only within the nucleolus and cytosol

16. A microbiology student is examining various bacterial structures and their functions. Which of the following statements about prokaryotic morphology and adaptations is incorrect?

1) Mycoplasma species survive without a rigid cell wall due to their sterol-rich plasma membrane
2) Pili and fimbriae primarily function as locomotory appendages that help bacteria move across surfaces
3) Peptidoglycan forms the characteristic structural framework of most bacterial cell walls
4) Cyanobacteria display movements such as gliding but never possess true flagellated cells

17. During aerobic respiration, the organelle that hosts enzymes of the Krebs cycle and contains the inner membrane where the electron transport chain generates the majority of cellular ATP is:

1) Lysosome
2) Ribosome
3) Chloroplast
4) Mitochondrion

18.
Choose the correct option from the codes given below:

1) A-III, B-I, C-IV, D-II
2) A-II, B-III, C-IV, D-I
3) A-I, B-III, C-II, D-IV
4) A-II, B-I, C-IV, D-III

19. Assertion A: Arrangement in cilia and flagella is said to be a 9 + 2 array.
      Reason R: They have 9 doublet microtubules at the periphery and 1 pair of microtubules at the centre.

1) A is true but R is false.
2) A is false but R is true.
3) Both A and R are true and R is the correct explanation of A.
4) Both A and R are true but R is not the correct explanation of A.

20. Identify from the following which is/are not have double membrane.
I. Vacuole
II. Mitochondria
III. Lysosomes
IV. Endoplasmic reticulum
Choose the most appropriate answer from the options given below:

1) I, II, and IV only
2) II only
3) II, III and IV only
4) All except II

21. Which of the following is incorrect about microbodies?

1) These are membrane bound structures.
2) These are a type of vesicles.
3) They contain various enzymes.
4) These structures are present only in plant.

22. Which of the following pair of organisms possess 80S ribosome?

1) Mycoplasma and plants
2) Cyanobacteria and plants
3) Blue green and purple and green photosynthetic bacteria
4) Fungi and Protista

23. Assertion (A): Adrenal medulla secretes catecholamines.
      Reason (R): These hormones increase heart rate and blood glucose level.

1) Both A and R are true and R explains A
2) Both A and R are true but R does not explain A
3) A is true but R is false
4) A is false but R is true

24. Which part of the pituitary stores ADH and Oxytocin?

1) Pars distalis
2) Pars tuberalis
3) Pars intermedia
4) Pars nervosa

25. Which of the following pairs is mismatched?

1) Myxoedema – Adults – Hypothyroidism
2) Simple goitre – Hyperthyroidism
3) Cretinism – Children – Hypothyroidism
4) Exophthalmic goitre – Hyperthyroidism

26. Which of the following pairs is incorrectly matched?

1) Zona glomerulosa – Aldosterone – Na⁺ reabsorption
2) Zona fasciculata – Cortisol – Gluconeogenesis
3) Zona reticularis – Androgens – Secondary sex characters
4) Zona fasciculata – Adrenaline – Fight or flight

27. A woman with persistent corpus luteum shows which hormonal pattern?

1) High estrogen, low progesterone
2) Low estrogen, high progesterone
3) High progesterone, suppressed FSH & LH
4) Elevated LH with normal FSH

28. Which hormone among the following shows antagonistic action to PTH?

1) Thymosin
2) Cortisol
3) Glucagon
4) Calcitonin

29. Which of the following hormones does not follow cAMP second messenger pathway?

1) TSH
2) FSH
3) GH
4) ACTH

30. Assertion (A): Hypothalamus acts as a link between the nervous and endocrine systems.
      Reason (R): It secretes releasing and inhibitory hormones.

1) Both A and R are true and R explains A
2) Both A and R are true but R does not explain A
3) A is true but R is false
4) A is false but R is true

31. Select the correct sequence of hormone secretion in stress response: A.

1) CRH → ACTH → Cortisol
2) ACTH → CRH → Cortisol
3) Cortisol → ACTH → CRH
4) CRH → Cortisol → ACTH

32. A woman shows reduced secretion of TSH, LH, and FSH despite normal pituitary structure. The problem lies in the regulatory control of the pituitary. The most likely defect is in the secretion of:

1) ADH
2) Releasing hormones
3) Oxytocin
4) Inhibitory hormones

33. Which pair of hormones share the same mechanism of action?

1) Insulin and Adrenaline
2) Thyroxine and Cortisol
3) Growth hormone and Prolactin
4) Aldosterone and ADH

34. Which of the following statements about the pituitary gland is correct?

1) Adenohypophysis and neurohypophysis have the same embryonic origin
2) Pars intermedia is well developed in humans
3) Pituitary gland is known as the master gland
4) Neurohypophysis secretes hormones synthesized by itself

35. Assertion (A): PTH increases calcium in blood.
      Reason (R): PTH increases renal excretion of calcium.

1) Both true, R explains A
2) Both true, R does not explain A
3) A true, R false
4) A false, R true

36. Which hormone causes increased transcription of genes by binding to nuclear receptors?

1) Insulin
2) Adrenaline
3) Thyroxine
4) Glucagon

37. Select incorrect statement best differentiates oxytocin and prolactin?

1) Both are synthesized in anterior pituitary
2) Oxytocin causes milk synthesis, prolactin causes milk ejection
3) Oxytocin is neurohypophyseal, prolactin is adenohypophyseal
4) Both act via cAMP pathway

38. Thyroid hormone acts by:

1) Binding to membrane receptors and activating second messengers
2) Entering nucleus and altering gene transcription
3) Stimulating adenyl cyclase
4) Opening calcium channels

39. Which pair is correctly matched with respect to chemical nature?

1) Insulin – Steroid
2) Testosterone – Peptide
3) Glucagon – Protein
4) Thyroxine – Steroid

40. Pineal gland primarily regulates circadian rhythm through secretion of melatonin.
Which statement regarding melatonin is correct?

1) Secretion increases in bright light
2) It inhibits GnRH release from hypothalamus
3) It is a steroid hormone synthesized from cholesterol
4) It is secreted by pars intermedia of pituitary

41. A hormone shows the following properties:
i. Synthesised from cholesterol
ii. Diffuses through plasma membrane
iii. Modulates gene transcription by binding to nuclear receptor
The hormone most likely is:

1) Epinephrine
2) Thyroxine
3) Cortisol
4) Insulin

42. Which of the following hormones is mismatched with its chemical class and mechanism of action?

1) Aldosterone – Steroid – Nuclear
2) Insulin – Protein – Membrane
3) Thyroxine – Amine – Cytosolic
4) ADH – Peptide – Nuclear

43. Which of the following pairs share similar chemical nature but different mechanism of action

1) Thyroxine & Cortisol
2) Insulin & Glucagon
3) Adrenaline & Thyroxine
4) Progesterone & Aldosterone

44. Select the correct combination:

1) Thymus-Thymosin-Biological clock
2) Pineal-Melatonin-Sleep-wake cycle
3) Pineal-Thymosin-Immunity
4) Thymus-Melatonin-Puberty

45. GIFT involves transfer of

1) A mixture of sperm and ova into the uterus
2) Embryo into the uterus
3) A mixture of sperm and ova into the fallopian tube
4) Zygote into the fallopian tube

46. Lippe’s loop is

1) Non-medicated IUD
2) Hormone releasing IUD
3) Copper releasing IUD
4) Both 1 and 2

47. The test-tube baby programme employs which one of the following techniques?

1) ICSI
2) IUI
3) GIFT
4) ZIFT

48. Which of the following is incorrect regarding vaccination?

1) The principle of immunization is based on the property of memory of immune system
2) Vaccines generate memory B and T cells that recognize pathogen quickly on subsequent exposure
3) Hepatitis B vaccine is produced from yeast through recombinant DNA technology
4) None of these

49. The substance given to cancer patients in order to activate their immune system and destroy the tumour is

1) Histamine
2) Interleukin
3) α-interferon
4) morphine

50. Which of the following is/are a member of the group of chemicals whose chemical structure is given below?

1) Morphine
2) Ganja
3) Codeine
4) None of these

51. Read the following statements.
(a) Colostrum is recommended for new borns because it is rich in antigens
(b) Typhoid is an autoimmune disease
(c) An antibody is a protein molecule containing four light chains
How many of the above statements are wrong?

1) 0
2) 1
3) 2
4) 3

52. An antigen is

1) Residue of antibody
2) A stimulus for antibody formation
3) Results of antibody
4) Opposite to antibody

53. Match the following


1) A-Q, B-S, C-R, D-P
2) A-P, B-R, C-Q, D-S
3) A-R, B-P, C-Q, D-S
4) A-S, B-Q, C-R, D-P

54. The function of histamine is

1) Vasoconstriction of blood vesel
2) Vasodilation of blood vessel
3) Phogocytosis
4) No effect on blood vessel

55. Proto-oncogenes are

1) Cancer causing genes
2) Normal cellular genes
3) Tumour supressor genes
4) BRCA1 genes

56. Every time when the dosage of a drug has to be increased to achieve the same kick that initially occurred in response to a smaller dose, this condition is known as

1) Tolerance
2) Rebound effect
3) Addiction
4) Withdrawal symptoms 

57. Statement I: Aedes mosquitoes are the causative agent for diseases like dengue and filariasis
      Statement II: Smallpox is a completely eradicated disease

1) Only Statement I is correct
2) Only Statement II is correct
3) Both statements are correct
4) Both statements are incorrect

58. Which of the following statement is wrong regarding AIDS?

1) HIV, the causative agent for AIDS is a retro-virus
2) The target cells of AIDS is helper T lymphocytes
3) The genome of HIV is conjugated with the enzyme protease
4) The symptoms of AIDS is seen when bursting of RBC occurs

59. Which of the following is an allergen?
(a) Pollen grains (b) Dust
(c) Mites in dust (d) Animal dander

1) a, b and d
2) a, c and d
3) b, c and d
4) All of these

60. The infectious stage of plasmodium, ie sporozoites are stored in

1) Salivary glands of mosquito
2) RBCs of human
3) Liver of infected man
4) Gut of mosquito

61. The pathogen specific immunity is

1) Innate immunity
2) Acquired immunity
3) Physical barrier
4) None of these

62. Assertion (A): Subsequent encounter with the same pathogen elicits a highly intensified anamnestic response
      Reason (R): Our body develops memory cells during the first encounter of pathogens

1) Both (A) and (R) are true, and (R) is the correct explanation of (A)
2) Both (A) and (R) are true, but (R) is not the correct explanation of (A)
3) (A) is true but (R) is false
4) Both (A) and (R) are false

63. Choose the correct statement
I. According to WHO, reproductive health is total well being in the physical, social, emotional and behavioural aspects of reproduction
II. According to WHO, reproductive health is total well being in the physical, social and emotional aspects of reproduction
III. A reproductively healthy society has people with physically and functionally normal reproductive organs
IV. A reproductively healthy society has abnormal sex-related emotional and behavioural interactions

1) I, II and III
2) II and IV
3) I and III
4) I only

64. Assertion (A): Amniocentesis for sex determination is one of the strategies of Reproductive and Child Health Care Programme
     Reason (R): Ban on amniocentesis checks increasing menase of female foeticide

1) Both (A) and (R) are true, and (R) is the correct explanation of (A)
2) Both (A) and (R) are true, but (R) is not the correct explanation of (A)
3) (A) is true but (R) is false
4) (A) is false but (R) is true

65. Intensely lactating mothers do not generally conceive due to

1) Supression of gonadotropins
2) Hyper secretion gonadotropins
3) Supression of estrogen
4) Positive feedback to hypothalamus

66. Which of the following is incorrectly matched?

1) Lactational amenorrhoea – natural contraceptive method
2) Lippes loop – non-medicated IUCD
3) Saheli – steroidal pills
4) Test tube baby – in vitro fertilization

67. The following diagram depicts which type of contraceptive technique?

1) Tubectomy
2) Vasectomy
3) Implants
4) IUD

68. Which of the following correctly matches the type of hydrophily with the plant?

1) Vallisneria – Submerged hydrophily
2) Zostera – Surface hydrophily
3) Vallisneria – Pollination at water surface
4) Zostera – Pollination by insects

69. Which is not related to hydrophily?

1) Surface pollination
2) Submerged pollination
3) Ribbon-like pollena
4) Sticky, scented pollen

70. In Vallisneria, the female flower reaches the water surface with the help of —

1) A long stalk
2) Floating pollen grains
3) Ribbon-like pollen
4) Air-filled petals

71. What is the function of synergids during fertilisation?

1) Form endosperm
2) Attract the pollen tube
3) Form antipodals
4) Produce egg nucleus

72. Which of the following is a post fertilisation event in angiosperms?

1) Pollen germination
2) Pollen tube entry into the ovule
3) Double fertilisation
4) Development of endosperm and embryo

73. Which is an advantage of cleistogamy?

1) Promotes variation
2) Ensures seed set
3) Promotes cross pollination
4) Lowers plant fitness

74. Which statement is TRUE about apomixis?

1) It requires fertilisation
2) It produces genetically identical seeds
3) It cannot occur in hybrids
4) It always involves meiosis

75. Perisperm refers to —

1) Persistent endosperm
2) Persistent nucellus
3) Persistent embryo
4) Persistent integument

76. Which of the following is NOT a part of pollen–pistil interaction?

1) Recognition
2) Rejection
3) Pollen tube entry
4) Double fertilisation

77. Double fertilisation produces —

1) One diploid zygote only
2) One diploid zygote + one triploid endosperm nucleus
3) Two diploid nuclei
4) One triploid zygote

78. Embryogeny starts with —

1) Division of antipodal cells
2) Division of zygote
3) Degeneration of synergids
4) Second mitotic division in embryo sac

79. In angiosperms, the pollen tube releases its contents into —

1) Central cell
2) Egg
3) One synergid
4) Antipodal cell

80. Identify the wrong match

1) Entomophily – insects
2) Ornithophily – birds
3) Chiropterophily – bats
4) Hydrophily – all aquatic plants

81. Identify the correct sequence of events after fertilisation in a typical angiosperm

1) Zygote → Fruit → Endosperm → See
2) Endosperm → Zygote → Fruit → See
3) Zygote → Embryo → Seed → Fruit
4) Zygote → Embryo → Endosperm → Fruit

82. Which structure usually develops before the embryo?

1) Endosperm
2) Cotyledon1
3) Seed coat
4) Suspensor

83. Which event directly follows syngamy?

1) Development of endosperm
2) Development of zygote
3) Formation of embryo sac
4) Fusion of polar nuclei

84. Which of the following directly affects the number of seeds in a fruit?

1) Number of ovules
2) Number of embryo sacs
3) Number of pollen grains on stigma
4) Number of style branches

85. A mature, viable, albuminous seed willretain:

1) Perisperm
2) Endosperm
3) Embryo sac
4) Zygote

86. Which event occurs first after the pollen tube releases the male gametes?

1) Formation of zygote
2) Triple fusion
3) Development of seed coat
4) Endosperm development

87. The primary endosperm nucleus (PEN) is:

1) Haploid
2) Diploid
3) Triploid
4) Tetraploid

88. Which part forms the major portion of the mature dicot seed?

1. Endosperm
2. Cotyledons
3. Perisperm
4. Micropyle

89. In a mature ovule, if only one integument transforms after fertilisation, the seed will have:

1) No seed coat
2) A thin seed coat
3) A single-layered testa
4) Embryo but no endosperm

90. During fruit formation, the region where funiculus attaches to the seed becomes:

1) Micropyle
2) Hilum
3) Raphe
4) Chalaza