300+ REAL TIME NEET Biology Objective Questions & Answers 2023

300+ TOP MCQs on Lac Operon and Answers

NEET Biology is the vey important paper in the medical entrance exam. Here, you will discover the NEET Biology MCQs and Answers for all Concepts as per the latest syllabus. Practice more on a regular basis with these NEET Biology objective questions on air pollution . NEET Biology Lac Operon Multiple Choice Questions

MCQs on Lac Operon :

1. Lac operon is an example of
(a) only positive regulation
(b) only negative regulation
(c) both positive and negative regulation
(d) sometimes positive sometimes negative

Answer

Answer: (c)

2. In the presence of lactose, how long does it take for the lac operon to be expressed?
(a) when lactose equals glucose concentration
(b) when glucose is more than lactose concentration
(c) as long as lactose is more than glucose concentration
(d) as long as lactose is more than galactose concentration

Answer

Answer: (c)

3. Which of these acts as an inducer of the lac operon?
(a) Allolactose
(b) Lactose
(c) Galactose
(d) Glucose

Answer

Answer: (a)

4. The sequence of the structural genes in the lac operon is
(a) lacA-lacZ-lacY
(b) lacZ-lacY-lacA
(c) lacZ-lacA-lacY
(d) lacA-lacY-lacZ

Answer

Answer: (b)

5. Regulation of the lac operon can be envisioned as regulation of enzyme synthesis by its
(a) lactose
(b) substrate
(c) carbohydrates
(d) all of the above

Answer

Answer: (d)

6. Lac Operon will be turned on when
(a) Lactose is less than glucose
(b) Lactose is less in the medium
(c) Lactose in more than glucose
(d) Glucose is enough in the medium

Answer

Answer: (c)

7. This will be prevented if the activator fastens to the repressor
(a) Transcription
(b) Binding of the RNA polymerase to the promoter
(c) Binding of the repressor to the operator
(d) Binding of the repressor to the promoter

Answer

Answer: (c)

8. In Lac-operon, the gene product of LacA gene is
(a) Beta-galactoside permease
(b) Beta-galactoside transacetylase
(c) Beta-galactosidase
(d) Beta-galactoside isomerase

Answer

Answer: (b)

9. This condition in lac operon facilitates the condition of lac genes being transcribed at high levels
(a) low glucose, high lactose
(b) low glucose, low lactose
(c) high glucose, high lactose
(d) high glucose, low lactose

Answer

Answer: (a)

10. The correct option regarding the lac operon in E.coli from the following is
(a) Lac operon is switched on in the absence of lactose
(b) Lac repressor binds to the lac promoter
(c) β-galactosidase is the only enzyme produced in large quantities when lac operon is turned on
(d) lac operon messenger RNA is a polycistronic mRNA

Answer

Answer: (d)

300+ TOP MCQs on Nostoc and Answers

MCQs on Nostoc :

1. Find the correct statement
(a) Paramecium, Penicillium and Plasmodium belong to the same kingdom
(b) Nostoc and Anabaena come under Protista
(c) lichen is a symbiotic association of an alga and Protozoan
(d) Yeast is a fungus and is used in bread and beer production

Answer

Answer: (d)

2. Cyanobacteria are
(a) oxygenic without nitrogenase
(b) non-oxygenic without nitrogenase
(c) oxygenic with nitrogenase
(d) non-oxygenic with nitrogenase

Answer

Answer: (c)

3. Blue-green algae are included in
(a) Prokaryotes
(b) Protista
(c) Fungi
(d) Bryophytes

Answer

Answer: (a)

4. An organism that forms a symbiotic association with Anthoceros
(a) Spirogyra
(b) Nostoc
(c) Ulothrix
(d) All of the above

Answer

Answer: (b)

5. Which of the following structure contains a polar nodule on both ends
(a) heterocyst
(b) hormogonia
(c) akinetes
(d) None of the above

Answer

Answer: (a)

6. Nostoc form
(a) compound colony
(b) simple colony
(c) both (a) and (b)
(d) None of these

Answer

Answer: (c)

7. Which of the angiosperm contains Nostoc as an endophyte?
(a) Gunnera manicata
(b) Arachis hypogea
(c) Melia indica
(d) None of the above

Answer

Answer: (a)

8. Coloured portion of the nostoc cell is
(a) genophore
(b) inner centroplasm
(c) outer chromoplasm
(d) central body

Answer

Answer: (c)

9. Heterocyst of Nostoc are
(a) intercalary
(b) terminal
(c) both terminal and intercalary
(d) none

Answer

Answer: (a)

10. Sexual reproduction is absent in
(a) Volvox
(b) Nostoc
(c) Aspergillus
(d) Ulothrix

Answer

Answer: (b)

300+ TOP MCQs on Apomixis and Answers

MCQs on Apomixis :

1. In many laboratories, active research is on to comprehend the genetics of apomixis
(a) Apomixis generates genetically different individuals
(b) Apomixis is the method to produce seeds without fertilization
(c) Hybrid plants are directly formed by apomixis
(d) Transfer of apomictic genes into hybrid varieties that shall prevent hybrid vigour loss over the years

Answer

Answer: (d)

2. Apomixis is a form of
(a) Vernalization
(b) Parthenogenesis
(c) Parthenocarpy
(d) None of the above

Answer

Answer: (b)

3. Geitonogamy and autogamy both are prevented in which one of these?
(a) Cucumber
(b) Maize
(c) Castor
(d) Papaya

Answer

Answer: (d)

4. In plants, apomixis pertains to plant development
(a) from root cuttings
(b) from cuttings of stem
(c) without the gametes having to fuse
(d) fusion of gametes

Answer

Answer: (c)

5. The reason why hybrid seeds have to be produced every year is
(a) hybrid seed industry tends to increase the cost of seeds
(b) hybrid plants turn sterile in coming years
(c) show more heterosis in coming years
(d) hybrid vigour is not maintained in more than one generation as segregation of genes is initiated in the second generation

Answer

Answer: (d)

6. In adventive embryony, a type of apomixis, the embryo develops directly from the
(a) Zygote
(b) accessory embryo sacs in the ovule
(c) antipodals or synergids in an embryo sac
(d) integuments or nucleus

Answer

Answer: (d)

7. Megasporium is equivalent to
(a) ovule
(b) embryo sac
(c) fruit
(d) Nucleus

Answer

Answer: (a)

8. One of these statements about apomixis is incorrect
(a) formation of seeds without fertilization
(b) Meiotic division and fertilization of gametes takes place to form a zygote
(c) Seeds are genetically similar
(d) None of these

Answer

Answer: (b)

9. This about apomixis is true:
(a) There is no fertilization involved in both apomixis and parthenocarpy
(b) Apomixis produces genetically identical mother cells
(c) Apomixis is observed in angiosperms and gymnosperms
(d) All of the above

Answer

Answer: (d)

10. The difference between perisperm and endosperm is that perisperm:
(a) has reserve food
(b) forms by fusion of the secondary nucleus with several sperms
(c) is a diploid tissue
(d) is a haploid tissue

Answer

Answer: (c)

300+ TOP MCQs on Parenchyma Cells and Answers

MCQs on Parenchyma Cells :

1. Mostly, the flesh of fruit is made of
(a) Collenchyma
(b) Parenchyma
(c) Meristem
(d) Schlerids

Answer

Answer: (b)

2. Prosenchyma is a type of
(a) Chlorenchyma
(b) Collenchyma
(c) Sclerenchyma
(d) Parenchyma

Answer

Answer: (d)

3. The tissue where cells are thin-walled, living, isodiametric along with intercellular spaces is
(a) Arenchyma
(b) Prosenchyma
(c) Collenchyma
(d) Parenchyma

Answer

Answer: (d)

4. The plant tissue with the following characteristics is –
– Oval/round-shaped cells
– Cells have a living protoplasm and are dense
– Cell wall is made of cellulose or hemicellulose
– Thin-walled cells
(a) Parenchyma
(b) Collenchyma
(c) Scherenchyma
(d) Epidermis

Answer

Answer: (a)

5. The main purpose that the aerenchyma serves in Parenchyma is
(a) Offers flexibility
(b) Renders Buoyancy
(c) Provides structural framework
(d) Provides mechanical support

Answer

Answer: (b)

6. Which of this is not a function that Parenchyma performs
(a) Stores nutrients and food
(b) Aids in regeneration, healing and repairs wounds
(c) Provides foundation and support
(d) None of these

Answer

Answer: (d)

7. The tissue that provides maximum mechanical strength to the plant is
(a) Xylem
(b) Phloem
(c) Parenchyma
(d) Collenchyma

Answer

Answer: (a)

8. Parenchyma cells in the spongy mesophyll exhibit large intercellular spaces promoting:
(a) To become nutrients for the future germinating embryo
(b) Greater exposure to carbon dioxide
(c) To distribute pressure evenly through the structure
(d) No specific reason

Answer

Answer: (b)

9. Vessels are found in
(a) Most of the angiosperms and few gymnosperms
(b) All angiosperms and some gymnosperms
(c) All angiosperms, all gymnosperms and some pteridophytes
(d) All pteridophytes

Answer

Answer: (a)

10. The main difference between parenchyma, collenchyma and sclerenchyma is that
(a) Parenchyma is involved in photosynthesis, secretion and storage
(b) Collenchyma is involved in support and transportation of nutrients
(c) Sclerenchyma is involved in support, protection, transportation of nutrients and water
(d) All of these

Answer

Answer: (d)

300+ TOP MCQs on Cell Cycle Phases and Answers

MCQs on Cell Cycle Phases :

1. The division of cytoplasm is known as
(a) Mitosis
(b) Synapsis
(c) Cytokinesis
(d) Karyokinesis

Answer

Answer: (c)

2. The stage in which chromosomes align on the equator of spindle fiber is
(a) Telophase
(b) Anaphase
(c) Metaphase
(d) Prophase

Answer

Answer: (c)

3. The best stage at which the total number of chromosomes can be counted in any species is
(a) Telophase
(b) Metaphase
(c) Late anaphase
(d) Late prophase

Answer

Answer: (b)

4. Balbiani rings are found in
(a) Heterosome
(b) Lampbrush chromosome
(c) Autosome
(d) Polytene chromsome

Answer

Answer: (d)

5. This structure tends to vanish always during meiosis and mitosis
(a) Plastids
(b) Plasma membrane
(c) Nucleolus and nuclear membrane
(d) All of these

Answer

Answer: (c)

6. Centrosome duplication takes place in this phase
(a) S phase
(b) G1 phase
(c) G0 phase
(d) M phase

Answer

Answer: (a)

7. The __________ checkpoint is also known as restriction point
(a) G1 checkpoint
(b) G2 checkpoint
(c) M checkpoint
(d) None of these

Answer

Answer: (a)

8. The characteristic of this stage of mitosis is the separation of the sister chromatids
(a) Telophase
(b) Metaphase
(c) Prometaphase
(d) Anaphase

Answer

Answer: (d)

9. This condition is necessary for a cell to qualify through the G2 checkpoint
(a) Cell should be of a size sufficient enough
(b) Complete and accurate DNA replication
(c) Sufficient stockpile of nucleotides
(d) Complete attachment of mitotic spindle fibers to kinetochores

Answer

Answer: (b)

10. Individual chromosomes become distinct through a light microscope during this mitotic stage
(a) Prometaphase
(b) Prophase
(c) Anaphase
(d) Metaphase

Answer

Answer: (b)

300+ TOP MCQs on Lichens and Answers

MCQs on Lichens :

1. This is a crutose lichen
(a) Peltigera
(b) Usnea
(c) Rhizocarpon
(d) None of the above

Answer

Answer: (c)

2. Most of the scientists deem the algal-fungal relationship in lichens as helotism. Helotism is a
(a) master-master relationship
(b) master-slave relationship
(c) a kind of mutualism
(d) a kind of symbiotic association

Answer

Answer: (b)

3. Majorly, lichens are the pollution indicators of
(a) CO
(b) Mercury
(c) NO₂
(d) SO₂

Answer

Answer: (d)

4. The symbiotic association of algae and fungi is known as
(a) Mycorrhiza
(b) lichen
(c) Mycoplasma
(d) Both (a) and (b)

Answer

Answer: (b)

5. Vegetative reproduction in lichens takes place by
(a) isidia
(b) soredia
(c) fragmentation
(d) all of the above

Answer

Answer: (d)

6. In the studies on the atmospheric pollution, lichens are important as they
(a) can readily multiply in polluted atmosphere
(b) are very sensitive to pollutants
(c) efficiently purify the atmosphere
(d) can also be grown in greatly polluted atmosphere

Answer

Answer: (b)

7. This lichen is pioneer in xerosere
(a) fruticose lichen
(b) foliose lichen
(c) crustose lichen
(d) leprose lichen

Answer

Answer: (c)

8. A common phycobiont in lichens are
(a) Cetraria
(b) Microcystis
(c) Trebouxia
(d) Oedogonium

Answer

Answer: (c)

9. Reindeer moss is a lichen known as
(a) Usnea
(b) Rocella
(c) Cladonia
(d) Parmelia

Answer

Answer: (c)

10. This about lichens is incorrect
(a) Lichens are indicators of pollution
(b) They grow rapidly about 2cm every day
(c) Some species are eaten by reindeers
(d) They have symbiotic relationship between alga and fungus

Answer

Answer: (b)