Cell Cycle

Q1: How many chromatids are there in a duplicated chromosome?

A One

B Two

C Three

D Four

ANS:B - Two

No answer description is available.

Q2: At which of the following check point, mitosis is controlled?

A G1

B G2

C M

D S

ANS:B - G2

What is mitosis is controlled? Not clear.

In G2 if all enzymes/necessary proteins are available and before mitosis starts.

In M: when all spindles are attached to the kinetochore anaphase can start.

Q3: Which of the following from a blood clot stimulates the growth of cells in the healing process?

A EGF

B PDGF

C MPF

D NGF

ANS:B - PDGF

As @Rohini ji said that "Platelet-derived growth factor (PDGF) is proteins that regulate cell growth and division" which help as a catalyst in healing process.

Q4: Which of the following statements about mitosis is incorrect?

A The daughter nuclei are genetically identical to the parent nucleus

B Chromosomes separate during anaphase due to the interaction of polar microtubules from opposite poles pushing against each other

C Chromosomes separate during anaphase when the kinetochore microtubules shorten as they depolymerize

D Chromosomes move to the metaphase plate using motor proteins, a kind of kinesin, attached to spindle fibers

ANS:B - Chromosomes separate during anaphase due to the interaction of polar microtubules from opposite poles pushing against each other

No answer description is available.

Q5: How many chromatids does a diploid body cell contain just prior to cell division?

A 23

B 46

C 69

D 92

ANS:D - 92

Haploid cells contain 1 set of chromosomes in their nuclei. Diploid cells contain 2 sets of chromosomes in their nuclei. The human species contain 46 chromosomes in their nuclei. This is the diploid (2n) number. The sex cells of the species have 23 chromosomes in their nuclei. This is the haploid (n) number. When fertilisation takes place the 23 chromosomes (n) from the father (called Paternal chromosomes) and the 23 chromosomes (n) from the mother (called the Maternal chromosomes) combine to form the diploid (2n=46) number of chromosomes in the fertilised egg cell.

Q6: Which phase of mitosis is associated with chromosomes aligned at the center of the cell and centromeres divide?

A anaphase

B interphase

C metaphase

D prophase

ANS:C - metaphase

In metaphase chromosomes are lined up at the metaphase plate and each sister chromatid is attached to a spindle fibre originating from opposite pole This ordering of chromosomes is important in making sure that each new cell that is formed will contain an equal and identical amount of chromosomes.

Q7: A nuclear envelope forms around each set of sister chromatids in

A anaphase

B metaphase

C prophase

D telophase

ANS:D - telophase

No answer description is available.

Q8: Cells which no longer divide (such as certain specialized cells found in the human brain) remain in which phase of the cell cycle?

A Prophase

B S phase

C G0 Phase

D Gl Phase

ANS:C - G0 Phase

G0 is also known as the quiescent phase where the cells remain metabolically active but no longer proliferate. And can re enter cell cycle by appropriate extracellular signals.

Q9: Which of the following is not a part of a human chromosome in any phase?

A Centriole

B Histone

C Nucleosome

D Centromere

ANS:A - Centriole

A centriole is an organelle (a small functional structure) inside a cell. Usually only animal cells have centrioles. Each cell has two pairs of centrioles (and each 'pair' is called a centrosome and has two centrioles arranged at right angles to each other). Centrioles are responsible for organizing something called a 'spindle' during cell division.

A centromere is a region in a chromosome. Each chromosome has two 'chromatids' joined together at the centromere (if you've seen a picture of a chromosome you'll know what I mean). And during cell division, the chromosome gets attached to the spindle at the centromere. You will learn all about it when you learn about cell division (mitosis & meiosis) at school.

Q10: A centromere is

A another name for kinetochore

B the structure to which microtubules attach

C a constriction on a chromosome bound to a disk

D all of the above

ANS:D - all of the above

They are not the same.

Kinetochore is a thick layer present on both the sides of a centromere, through which microtubules comes out.

Q11: In the cell cycle replication of the genome occurs in the

A G1 phase

B G2 phase

C M phase

D S phase

ANS:D - S phase

Replication of genome takes place in the S phase because this is where DNA replication occur.

Q12: Which phase of mitosis is associated with separation of chromatids?

A Prophase

B Metaphase

C Anaphase

D Telophase

ANS:C - Anaphase

I think it is telophase.

Q13: In prokaryotes, just before the cell divides, the two daughter genomes are attached side by side to the

A cell membrane

B replication origin

C centromeres

D equatorial plate

ANS:A - cell membrane

Please explain the answer in detail.

Q14: The phase of mitosis which is associated with the formation of the nuclear envelope, is

A prophase

B metaphase

C anaphase

D telophase

ANS:D - telophase

No answer description is available.

Q15: Which of the following is the normal cell cycle, primarily regulated at checkpoints?

A Metaphase in mitosis

B Anaphase, G1 boundary

C G1-S boundary

D S-G2 boundary

ANS:C - G1-S boundary

Because the question asked for the primary checkpoint. And that's why its G1-S.

Q16: At the center of the cell cycle control system is Cdk, a protein that

A is phosphorylated to become active

B binds to different cyclins

C is only active during mitosis

D manufactures growth factors

ANS:B - binds to different cyclins

No answer description is available.

Q17: What structure forms as a network of protein cables during cell division?

A Spindle

B Aster

C Kinetochore

D Chromatid

ANS:A - Spindle

No answer description is available.

Q18: In which of the following phase preparations for genome separation are made?

A C

B G1

C G2

D M

ANS:D - M

No answer description is available.

Q19: Which of the following begins when pairs of sister chromatids align in the center of the cell?

A Anaphase

B Interphase

C Metaphase

D Prophase

ANS:C - Metaphase

No answer description is available.

Q20: During which phase, a cleavage furrow is formed in animal cells?

A C

B G1

C G2

D M

ANS:A - C

In cell biology, the cleavage furrow is the indentation of the cell's surface that begins the progression of cleavage, by which animal and some algal cells undergo cytokinesis, the final splitting of the membrane, in the process cell division. The same proteins responsible for muscle contraction, actin and myosin, begin the process of forming the cleavage furrow. Other cytoskeletal proteins and actin binding proteins are involved in the procedure.

Q21: The cell cycle is controlled in most cells by

A time (after a certain length of time the cell divides)

B a series of checkpoints

C cell size (when the cell reaches a certain size, it divides)

D different cells exhibit different control strategies

ANS:D - different cells exhibit different control strategies

The correct answer is option B.

Q22: The event(s) which does not occur during interphase, is/are

A Chromatin condenses

B Protein Synthesis

C Organelles replication

D DNA replication

ANS:A - Chromatin condenses

Chromatin - a chromatin strand - consists of a DNA double helix with associated histone proteins, giving an appearance like a string with beads on it. The string is the DNA and the beads are separated clusters of 8 histones with DNA wrapped around them (technically, these are called nucleosome core particles, but most of the time they are just called nucleosomes).

Chromatin can fold upon itself to form higher-level structures, making it more compact. During prophase, that is what begins to occur: the chromatin begins condensing by twisting and coiling upon itself, making it shorter and more compact.

Q23: In which phase, each chromosome replicates to produce two sister chromatids?

A Anaphase

B Interphase

C Metaphase

D Prophase

ANS:B - Interphase

During S phase which is a part of Interphase, all the DNA in the cell are duplicated.

Q24: The spindle forms in the

A G1 phase

B G2 phase

C M phase

D S phase

ANS:C - M phase

I expect that students should answer such questions having knowing that spindle is formed so that it will provide extension that will pull or separate the sister chromatid lined on the metaphase plate.

Q25: The centromeres move toward the poles in __________ .

A anaphase

B interphase

C metaphase

D prophase

ANS:A - anaphase

Centromere start to move apart in prophase.

Q26: Sequences that correctly describes the cell cycle is

A -> G1-> G2 -> S -> mitosis -> cytokinesis ->

B -> S -> G2 -> mitosis -> cytokinesis -> G1 ->

C -> G1 ->S -> G2 -> cytokinesis -> mitosis ->

D ->cytokinesis-> mitosis -> G1 -> S -> G2 ->

ANS:B - -> S -> G2 -> mitosis -> cytokinesis -> G1 ->

B is the correct answer. Since it's a cycle, we can asume to start here from S-phase.

Q27: At the center of the cell cycle control system is Cdk, a protein that

A is phosphorylated to become active

B binds to different cyclins

C is only active during mitosis

D manufactures growth factors

ANS:B - binds to different cyclins

No answer description is available.

Q28: The G0 phase is

A a permanent state of all body cells

B the state of most cells in an animal body

C another name for interphase

D all of the above

ANS:B - the state of most cells in an animal body

No answer description is available.

Q29: Each chromosome contains two chromatids by the end of the __________ phase in the life cycle of a human cell.

A C

B G2

C M

D S

ANS:D - S

At prophase phase the chromosomal material condensed and chromosomes are seen to be composed of two chromatids attached together at the centromere (Cell Biology Karp).

Q30: At the __________ checkpoint, cell growth is controlled.

A C

B G1

C G2

D S

ANS:B - G1

No answer description is available.

Q31: DNA replication is controlled at which of the following checkpoint?

A G1

B G2

C M

D S

ANS:A - G1

It's G1 phase because of DNA replication goes when cells go under replication and it is controlled by G1 phase.

So, it is correct.

Q32: Which of the following triggers the division of activated T lymphocytes?

A FGF

B Interlukin 2

C PDGF

D Erythroprotein

ANS:B - Interlukin 2

Interleukins are the glycoprotein secreted by the leukocytes and these protein promote the growth of Band T cell of Lymphocytes.

Q33: The term, not related to mitosis is

A gametes

B chromosomes

C DNA replication

D somatic cells

ANS:A - gametes

Because mitosis cell division occurs in somatic cell not in reproductive cell.

Q34: Microtubules grow from the poles to kinetochores of each chromatid during

A prophase

B metaphase

C anaphase

D telophase

ANS:A - prophase

No answer description is available.

Q35: The term homologous chromosomes

A refers to replications of the same chromosome

B is another name for sister chromatids

C must be haploid

D means a pair of chromosomes of the same kind, such as sex chromosomes

ANS:D - means a pair of chromosomes of the same kind, such as sex chromosomes

The answer is wrong, as a pair of chromosomes of equal length, same centromere position and carry genes controlling same inherited characteristic Ave cashed homologous chromosomes.

And sex chromosomes are only partly homologous.

Q36: Cdks bind with __________ , enabling the Cdks to function as enzymes.

A MPF

B cyclins

C histones

D p53

ANS:B - cyclins

CDKs require the presence of cyclins to become active. Cyclins are a family of proteins that have no enzymatic activity of their own but activate CDKs by binding to them. CDKs must also be in a particular phosphorylation state with some sites phosphorylated and others dephosphorylated in order for activation to occur. Correct phosphorylation depends on the action of other kinases and a second class of enzymes called phosphatases that are responsible for removing phosphate groups from proteins.

Q37: Which of the following is the primary growth phase of a cell?

A G1

B G2

C M

D G0

ANS:A - G1

No answer description is available.



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