What is the significance of S-phase of cell cycle?

What is the significance of S-phase of cell cycle? 
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Ans: During S phase there is doubling of DNA due to semiconservative replication of DNA. The two chromatids of chromosomes are formed at the end of this stage. 
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Related questions

Write about the events of Pachytene and mention the significance of this phase.

Description : Write about the events of Pachytene and mention the significance of this phase. 

Last Answer : Ans: Events of Pachytene: 1. The two chromatids of chromosome are clearly seen. Each bivalent has 4 chromatids and known as Pachytene tetrad. Chromatids of the same chromosome are called as Sister ... This is responsible for the origin of new species which is one of the causes of evolution.

What is crossing over? What is its significance?

Description : What is crossing over? What is its significance?

Last Answer : Ans: Exchange of genetic material between homologous chromosomes during pachytene of meiosis is called as crossing over. It brings about variations in the offspring due to recombination. It helps in natural selection and evolution.  

The process by which the amount of DNA, RNA and protein can be known at a time is: (a) Cell fractionation (b) Autoradiography (c) Phase-contrast microscopy (d) Tissue culture

Description : The process by which the amount of DNA, RNA and protein can be known at a time is: (a) Cell fractionation (b) Autoradiography (c) Phase-contrast microscopy (d) Tissue culture

Last Answer : Ans. ((b))

Calvin cycle is: (1) C3 cycle (2) Reductive pentose-phosphate cycle (3) Common in cereals uncommon in cereals (4) Uncommon in cereals

Description : Calvin cycle is: (1) C3 cycle (2) Reductive pentose-phosphate cycle (3) Common in cereals uncommon in cereals (4) Uncommon in cereals

Last Answer : Ans. ((c))

A plant having two types of haploid structures in its life cycle is known as: (a) Haplobiontic (b) Diplobiontic (c) Haplontic (d) Diplontic

Description : A plant having two types of haploid structures in its life cycle is known as: (a) Haplobiontic (b) Diplobiontic (c) Haplontic (d) Diplontic

Last Answer : Ans. ((a))

The process through which the amount of DNA, RNA and protein can be known at a time is called (a) Autoradiography (b) Tissue culture (c) Cellular fractioning (d) Phase contrast microscopy

Description : The process through which the amount of DNA, RNA and protein can be known at a time is called (a) Autoradiography (b) Tissue culture (c) Cellular fractioning (d) Phase contrast microscopy

Last Answer : Ans. ((c))

Why do cell walls absorb water ?

Description : Why do cell walls absorb water ?

Last Answer : Plant cell walls absorb water. Because in the case of plants the cell walls are colloidal substances. And different types of colloidal substances exist in plants. Such as starch , gelatin , cellulose etc. These substances are able to absorb water due to their colloidal properties.

In which process of plant protoplasm and cell wall absorbs water ?

Description : In which process of plant protoplasm and cell wall absorbs water ?

Last Answer : The plant absorbs water in the process of protoplasm and cell wall adsorption.

Which cell acts as a semi-permeable screen in a cell ?

Description : Which cell acts as a semi-permeable screen in a cell ?

Last Answer : Answer : The plasma membrane in a cell acts as a semipermeable membrane.

What is the cell wall made of ?

Description : What is the cell wall made of ?

Last Answer : The cell wall is made up of cellulose.

Which of the following are true archaebacteria? (1) Extreme halophiles (2) Extreme thermophyles (3) Methanogens (4) Presence of peptidoglycan cell wall Ans. (a) 43; Which of the following are endangered plants ? (1) Saintpaulia ionantha (2) Ceratozamia hildae (3) Punica granatum (4) Senecio hadrasomum

Description : Which of the following are true archaebacteria? (1) Extreme halophiles (2) Extreme thermophyles (3) Methanogens (4) Presence of peptidoglycan cell wall Ans. (a) 43; Which of the following are ... plants ? (1) Saintpaulia ionantha (2) Ceratozamia hildae (3) Punica granatum (4) Senecio hadrasomum

Last Answer : Ans. ((c))

Consider the following statement: (1) In plant cells, cytokinesis start with the formation of the phragmoplast (2) Phragmoplast comprises intrazonal microtubules and Golgi vesicles (3) Primary cell wall is produced by microtubules (4) Phragmoplast is formed by nucleus

Description : Consider the following statement: (1) In plant cells, cytokinesis start with the formation of the phragmoplast (2) Phragmoplast comprises intrazonal microtubules and Golgi vesicles (3) Primary cell wall is produced by microtubules (4) Phragmoplast is formed by nucleus

Last Answer : Ans. ((a))

Which of the following statement is correct? (1) The causal organism for foolish seedling disease is the source of gibberellin (2) Abscisic acid is a growth promoter (3) The ratio of auxin : cytokinin control cell differentiation (4) Bolting of cabbage can be induced by treatment with IAA

Description : Which of the following statement is correct? (1) The causal organism for foolish seedling disease is the source of gibberellin (2) Abscisic acid is a growth promoter (3) The ratio of auxin : cytokinin control cell differentiation (4) Bolting of cabbage can be induced by treatment with IAA

Last Answer : Ans. ((d))

Cell ‘A’ with O.P = 10 atm and T.P =5 atm is in contact with cell ‘B’ having O.P = 15 atm and T.P = 12 atm. The flow of water will be: (a) From A to B (b) Equal flow (c) From B to A (d) No flow

Description : Cell ‘A’ with O.P = 10 atm and T.P =5 atm is in contact with cell ‘B’ having O.P = 15 atm and T.P = 12 atm. The flow of water will be: (a) From A to B (b) Equal flow (c) From B to A (d) No flow

Last Answer : Ans. ((c))

Colchicines bring about: (a) Polyploidy (b) Cell division (c) Cell elongation (d) Cell differentiation

Description : Colchicines bring about: (a) Polyploidy (b) Cell division (c) Cell elongation (d) Cell differentiation

Last Answer : Ans. ((a))

Cell organelle covered by single unit membrane is: (a) Glyoxisome (b) Lysosome (c) Peroxisomes (d) All of these.

Description : Cell organelle covered by single unit membrane is: (a) Glyoxisome (b) Lysosome (c) Peroxisomes (d) All of these.

Last Answer : Ans. ((d))

The cell wall of both bacteria and cyanobactena contains: (a) Lipid (b) Pectin (c) Protein (d) muramic acid

Description : The cell wall of both bacteria and cyanobactena contains: (a) Lipid (b) Pectin (c) Protein (d) muramic acid

Last Answer : Ans. ((d))

If a sporangium derived from a single cell is called (a) Leptosporangiate (b) Eusporangiate (c) Heterosporangiate (d) None of the above

Description : If a sporangium derived from a single cell is called (a) Leptosporangiate (b) Eusporangiate (c) Heterosporangiate (d) None of the above

Last Answer : Ans. ((a))

In angiosperms regarding development of microgametophyte each microspore mother cell undergoes (a) Mitosis to produce 4 microspores (b) Two successive mitosis to form 4 microspores (c) Two successive meiotic division to form 4 microspores (d) Meiosis to produce 4 haploid microspores

Description : In angiosperms regarding development of microgametophyte each microspore mother cell undergoes (a) Mitosis to produce 4 microspores (b) Two successive mitosis to form 4 microspores (c) Two successive meiotic division to form 4 microspores (d) Meiosis to produce 4 haploid microspores

Last Answer : Ans. ((d))

In spite of several angiospermic features Gnetum is a gymnosperm because…. a) polyembryony is a common features b) prothallial cell is present in the male gametophyte c) seed is naked d) stem exhibit anomalous secondary growth

Description : In spite of several angiospermic features Gnetum is a gymnosperm because…. a) polyembryony is a common features b) prothallial cell is present in the male gametophyte c) seed is naked d) stem exhibit anomalous secondary growth

Last Answer : c) seed is naked

Cell sap is found inside a. Protoplasm b. Cytoplasm c. Nucleoplasm d. Vacuole

Description : Cell sap is found inside a. Protoplasm b. Cytoplasm c. Nucleoplasm d. Vacuole

Last Answer : d. Vacuole

When the embryo develops from haploid egg cell without fertilization, the phenomenon is called as

Description : When the embryo develops from haploid egg cell without fertilization, the phenomenon is called as

Last Answer : When the embryo develops from haploid egg cell without fertilization, the phenomenon is called as – Haploid parthenogenesis

When a diploid embryosac is formed from a megaspore mother cell without meiosis, it is called as

Description : When a diploid embryosac is formed from a megaspore mother cell without meiosis, it is called as

Last Answer : When a diploid embryosac is formed from a megaspore mother cell without meiosis, it is called as – Diplospory

During microsporogenesis, successive type of cell division is found in

Description : During microsporogenesis, successive type of cell division is found in

Last Answer : During microsporogenesis, successive type of cell division is found in – Monocots

Egg cell without synergids is found in embryosac of

Description : Egg cell without synergids is found in embryosac of

Last Answer : Egg cell without synergids is found in embryosac of – Plumbagella type

Apical cell theory best explains the development in

Description : Apical cell theory best explains the development in

Last Answer : Apical cell theory best explains the development in – Cryptogams

Describe the cell organelle which is responsible for the synthesis of starch.

Description : Describe the cell organelle which is responsible for the synthesis of starch. 

Last Answer : The cell organelle responsible for the formation of starch is Chloroplast. It was discovered by Sachs and named by Schimper. It is usually disc shaped or Biconvex or Oval or spherical.   ... granum and the unstacked thylakoids that connect the adjacent grana are called as Stroma thylakoids.  

With the help of labeled diagram give an account of the cell organelle which is generally referred as Cell brain.

Description : With the help of labeled diagram give an account of the cell organelle which is generally referred as Cell brain.

Last Answer : Ans: Nucleus is the controlling centre of the cell that consists of chromosomes. Structurally it has four parts known as Nuclear envelope, Nucleoplasm, Nucleolus and Chromatin.   Nuclear ... chromosome at secondary constriction. It also disappears in Prophase and reappears in telophase.   

Give an account on suicidal bags of the cell.

Description : Give an account on suicidal bags of the cell. 

Last Answer : Ans: These are Lysosomes. They have single unit membrane and formed from E.R. and Golgi complex. These were discovered by de Duve. They are rich in hydrolytic enzymes and play a role in digestion. ... lysosomes can destroy the contents of the same cell they are called as Suicidal bags of the cell.

How do you identify a meristem cell and permanent cell under microscope.

Description : How do you identify a meristem cell and permanent cell under microscope.  

Last Answer : Ans:  

If there are 16 chromosomes in the cell of an angiospermic plant, how many chromosomes are there in the perisperm and endosperm cell

Description : If there are 16 chromosomes in the cell of an angiospermic plant, how many chromosomes are there in the perisperm and endosperm cell  

Last Answer : Ans: 16 in perisperm as it is diploid and 24 in endosperm as it is triploid  

In a cell haploid chromosome number is 15. What number is found in Pollen grain, Zygote, Primary endosperm nucleus and Colchicine treated zygote.

Description : In a cell haploid chromosome number is 15. What number is found in Pollen grain, Zygote, Primary endosperm nucleus and Colchicine treated zygote. 

Last Answer : Ans: 15 in pollen grain, 30 in zygote, 45 in Primary Endosperm nucleus and 60 in colchicine treated zygote.

Name the cell organelle associated with photorespiration? Who discovered it?

Description : Name the cell organelle associated with photorespiration? Who discovered it?

Last Answer : Ans: Peroxisome, Rhodin  

What is the role of golgi complex in cell division?

Description : What is the role of golgi complex in cell division?

Last Answer : Ans: During cell division the vesicles of Golgi are involved in the formation of cell plate at the equatorial region which eventually forms the middle lamellum. In this way Golgi plays a role in cytokinesis. 

In which stage of cell does crossing over occur? What is its role in the origin of species?

Description : In which stage of cell does crossing over occur? What is its role in the origin of species? 

Last Answer : Ans: Pachytene of Meiosis. It brings about variations in the off spring. Continuation of these variations for several generations leads to origin of new species. 

SO2 pollution causes a) Plasmolysis b) Destruction of cell wall c) Destruction of Golgi bodies

Description : SO2 pollution causes a) Plasmolysis b) Destruction of cell wall c) Destruction of Golgi bodies

Last Answer : c) Destruction of Golgi bodies

what happens during the S phase of the cell cycle -Biology

Description : what happens during the S phase of the cell cycle -Biology

Last Answer : answer:

what happens during the S phase of the cell cycle -Biology

Description : what happens during the S phase of the cell cycle -Biology

Last Answer : answer:

$ The regular sequences of a cell cycle is `G_(1),S,G_(2),M` and C ! Replication of DNA occurs during S phase.

Description : $ The regular sequences of a cell cycle is `G_(1),S,G_(2),M` and C ! Replication of DNA occurs during S phase.

Last Answer : $ The regular sequences of a cell cycle is `G_(1),S,G_(2),M` and C ! Replication of DNA occurs during ... , R is wrong D. If both As and R are wrong.

A somatic cell that has just completed has just completed the S-phase of its cell cycle, as compared to gamete of the same species, has

Description : A somatic cell that has just completed has just completed the S-phase of its cell cycle, as compared to gamete of the same species, has

Last Answer : A somatic cell that has just completed has just completed the S-phase of its cell cycle, as ... the number of chromosomes and twice the amount of DNA

During which phase(s) of cell cycle amount of DNA in a cell remains at 4C level if the initial amount is denoted an 2C

Description : During which phase(s) of cell cycle amount of DNA in a cell remains at 4C level if the initial amount is denoted an 2C

Last Answer : During which phase(s) of cell cycle amount of DNA in a cell remains at 4C level if the initial amount is denoted ... Only `G_(2)` D. `G_(2)" and M`

In mammalian cell cycle, synthesis of DNA occurs during (A) S phase (B) G1 phase (C) Mitotic Phase (D) G2 phase

Description : In mammalian cell cycle, synthesis of DNA occurs during (A) S phase (B) G1 phase (C) Mitotic Phase (D) G2 phase

Last Answer : Answer : A

In a somatic cell cycle, DNA synthesis takes place in (a) G1 phase (b) prophase of mitosis (c) S-phase (d) G2 phase.

Description : In a somatic cell cycle, DNA synthesis takes place in (a) G1 phase (b) prophase of mitosis (c) S-phase (d) G2 phase.

Last Answer : (c) S-phase

In which stage of cell cycle, DNA replication occurs? (a) G1-phase (b) S-phase (c) G2-phase (d) M-phase

Description : In which stage of cell cycle, DNA replication occurs? (a) G1-phase (b) S-phase (c) G2-phase (d) M-phase

Last Answer : (b) S-phase

In the somatic cell cycle (a) in G1 phase DNA content is double the amount of DNA present in the original cell (b) DNA replication takes place in S phase (c) a short interphase is followed by a long mitotic phase (d) G2 phase follows mitotic phase.

Description : In the somatic cell cycle (a) in G1 phase DNA content is double the amount of DNA present in the original cell (b) DNA replication takes place in S phase (c) a short interphase is followed by a long mitotic phase (d) G2 phase follows mitotic phase.

Last Answer : (b) DNA replication takes place in S phase

At what stage of the cell cycle are histone proteins synthesized in a eukaryotic cell? (a) During G2 stage of prophase (b) During S-phase (c) During entire prophase (d) During telophase

Description : At what stage of the cell cycle are histone proteins synthesized in a eukaryotic cell? (a) During G2 stage of prophase (b) During S-phase (c) During entire prophase (d) During telophase

Last Answer : (b) During S-phase

In ‘S’ phase of the cell cycle (a) amount of DNA doubles in each cell (b) amount of DNA remains same in each cell (c) chromosome number is increased (d) amount of DNA is reduced to half in each cell.

Description : In ‘S’ phase of the cell cycle (a) amount of DNA doubles in each cell (b) amount of DNA remains same in each cell (c) chromosome number is increased (d) amount of DNA is reduced to half in each cell.

Last Answer : (a) amount of DNA doubles in each cell

During which phase(s) of cell cycle, amount of DNA in a cell remains at 4C level if the initial amount is denoted as 2C? (a) G0 and G1 (b) G1 and S (c) Only G2 (d) G2 and M

Description : During which phase(s) of cell cycle, amount of DNA in a cell remains at 4C level if the initial amount is denoted as 2C? (a) G0 and G1 (b) G1 and S (c) Only G2 (d) G2 and M

Last Answer : (c) Only G2

A somatic cell that has just completed the S phase of its cell cycle, as compared to gamete of the same species, has (a) twice the number of chromosomes and four times the amount of DNA(b) four times the number of chromosomes and twice the amount of DNA (c) twice the number of chromosomes and twice the amount of DNA (d) same number of chromosomes but twice the amount of DNA

Description : A somatic cell that has just completed the S phase of its cell cycle, as compared to gamete of the same species, has (a) twice the number of chromosomes and four times the amount of DNA (b) ... of chromosomes and twice the amount of DNA (d) same number of chromosomes but twice the amount of DNA

Last Answer : (a) twice the number of chromosomes and four times the amount of DNA

Some dividing cells exit the cell cycle and enter vegetative inactive stage. This is called quiescent stage (G0). This process occurs at the end of (a) M phase (b) G1 phase (c) S phase (d) G2 phase.

Description : Some dividing cells exit the cell cycle and enter vegetative inactive stage. This is called quiescent stage (G0). This process occurs at the end of (a) M phase (b) G1 phase (c) S phase (d) G2 phase.

Last Answer : (b) G1 phase