Diviziunea Celulară
Biologie clasa a IX-a Alegeți un singur răspuns corect:
Questions and Answers
- 1.
În interfază are loc:
- A.
Condensarea maximă a cromatinei
- B.
Dispariţia membranei nucleare
- C.
Dublarea cantităţii de ADN
- D.
Separarea cromatidelor
Correct Answer
C. Dublarea cantităţii de ADNExplanation
In the interface phase of the cell cycle, the DNA undergoes replication, resulting in the doubling of the amount of DNA. This is an essential step in preparation for cell division. The replication process ensures that each daughter cell receives a complete set of genetic information. The condensation of chromatin, disappearance of the nuclear membrane, and separation of chromatids occur in later stages of the cell cycle, during mitosis.Rate this question:
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- 2.
Cromozomii se aliniază în plan ecuatorial în:
- A.
Profaza
- B.
Metafază
- C.
Anafază
- D.
Telofază
Correct Answer
B. MetafazăExplanation
During metaphase, the chromosomes line up along the equatorial plane of the cell. This alignment is important for the proper separation of chromosomes during cell division. The chromosomes align in a single file line, with their centromeres attached to the spindle fibers. This alignment ensures that each daughter cell receives the correct number of chromosomes during cell division.Rate this question:
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- 3.
În diviziunea celulară, reorganizarea membranei nucleare are loc în:
- A.
Profază
- B.
Metafază
- C.
Anafază
- D.
Telofază
Correct Answer
D. TelofazăExplanation
During cell division, the reorganization of the nuclear membrane occurs in telophase. Telophase is the final stage of mitosis or meiosis, where the nuclear envelope reforms around the separated chromosomes at each pole of the cell. This process marks the completion of cell division and the formation of two daughter cells.Rate this question:
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- 4.
Tetradele cromatidice se formează în:
- A.
Anafază
- B.
Interfază
- C.
Mitoză
- D.
Meioză
Correct Answer
D. MeiozăExplanation
Tetradele cromatidice se formează în meioză. Meioza este un proces de diviziune celulară care are loc în celulele reproductive și care produce celulele sexuale (gametele). În etapa de profază I a meiozei, cromozomii omologi se apropie unul de celălalt și formează perechi numite tetrade. Fiecare cromozom din tetradele cromatidice este format din două cromatide identice. Această etapă este crucială pentru schimbul de material genetic între cromozomi, ceea ce contribuie la diversitatea genetică în organismele sexuate.Rate this question:
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- 5.
Faza mitozei caracterizată prin dezorganizarea învelişului nuclear este:
- A.
Profaza
- B.
Metafază
- C.
Anafază
- D.
Telofază
Correct Answer
A. ProfazaExplanation
In the process of mitosis, the phase characterized by the disorganization of the nuclear envelope is called the prophase. During prophase, the nuclear envelope breaks down, allowing the chromosomes to condense and become visible. This is followed by the formation of the mitotic spindle and the attachment of the chromosomes to the spindle fibers. Therefore, the correct answer is prophase.Rate this question:
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- 6.
Interfaza este:
- A.
Intervalul dintre două diviziuni
- B.
Prima etapă a mitozei
- C.
Etapă de reducere a cantității de ADN
- D.
Diviziunea celulei somatice
Correct Answer
A. Intervalul dintre două diviziuniExplanation
The correct answer is "intervalul dintre două diviziuni." This refers to the period of time between two cell divisions. During this interval, the cell undergoes various processes such as growth, DNA replication, and preparation for the next division. It is an important phase in the cell cycle as it allows the cell to replenish its resources and ensure proper division in the future.Rate this question:
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- 7.
Cromozomii se găsesc în:
- A.
Centromer
- B.
Lizozom
- C.
Nucleu
- D.
Ribozom
Correct Answer
C. NucleuExplanation
Cromozomii se găsesc în nucleu. Nucleul este o componentă esențială a celulei, care conține materialul genetic al organismului, inclusiv cromozomii. Cromozomii sunt structuri lungi și filamentare care conțin genele și informația genetică necesară pentru funcționarea și dezvoltarea organismului. Prin urmare, nucleul este locul principal în care se găsesc cromozomii.Rate this question:
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- 8.
Celulele formate prin diviziunea mitotică a unei celule - mamă cu 2n = 20 cromozomi prezintă fiecare:
- A.
N=10 cromozomi
- B.
N=20 cromozomi
- C.
2n=10 cromozomi
- D.
2n=20 cromozomi
Correct Answer
D. 2n=20 cromozomiExplanation
The correct answer is "2n=20 cromozomi". This answer indicates that the cells formed by mitotic division of a mother cell with 2n = 20 chromosomes will have 2n, which means they will also have 20 chromosomes. This is because during mitosis, the chromosomes are replicated and divided equally between the daughter cells, resulting in each daughter cell having the same number of chromosomes as the mother cell.Rate this question:
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- 9.
În cursul mitozei, fusul de diviziune se formează în:
- A.
Profază
- B.
Matafază
- C.
Anafază
- D.
Telofază
Correct Answer
A. ProfazăExplanation
During the prophase of mitosis, the spindle apparatus is formed. This is the stage where the chromosomes condense and become visible, and the nuclear envelope starts to break down. The spindle apparatus, composed of microtubules, forms and attaches to the chromosomes, preparing them for separation during the subsequent stages of mitosis. Therefore, the correct answer is prophase.Rate this question:
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- 10.
Cromozomii monocromatidici, aflaţi la jumătatea distanţei dintre zona ecuatorială a celulei şi polii acesteia, sunt caracteristici:
- A.
Anafazei I a meiozei
- B.
Anafazei mitozei
- C.
Metafazei mitozei
- D.
Telofazei I a meiozei
Correct Answer
B. Anafazei mitozeiExplanation
The given correct answer states that the monocentric chromatids are characteristic of anaphase in mitosis. This means that during mitosis, when the chromosomes are being pulled apart and separated into two daughter cells, the monocentric chromatids are found at the halfway point between the equatorial zone of the cell and its poles. This is a specific characteristic of anaphase in mitosis, where the chromosomes are actively moving and being separated.Rate this question:
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- 11.
Fiecare dintre celulele formate prin diviziunea mitotică a unei celule mamă cu 2n = 34 cromozomi are:
- A.
N=17 cromozomi
- B.
N=34 cromozomi
- C.
2n=17 cromozomi
- D.
2n=34 cromozomi
Correct Answer
D. 2n=34 cromozomiExplanation
The correct answer is "2n=34 cromozomi". This is because the given statement states that each cell formed through mitotic division of a mother cell with 2n=34 chromosomes has 2n=34 chromosomes. This means that the number of chromosomes in each daughter cell remains the same as the mother cell, which is 34 chromosomes.Rate this question:
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- 12.
În timpul profazei mitotice:
- A.
Se dublează cantitatea de ADN
- B.
Se realizează fecundaţia
- C.
Se individualizează cromozomii
- D.
Se reduce la jumătate numărul de cromozomi ai celulelor-fiice
Correct Answer
C. Se individualizează cromozomiiExplanation
During prophase of mitosis, the chromosomes condense and become visible under a microscope. This process is known as chromosome individualization. The chromosomes become more distinct and separate from each other, preparing for their subsequent alignment and separation during the later stages of mitosis. This individualization of chromosomes is essential for the accurate distribution of genetic material to the daughter cells.Rate this question:
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- 13.
Dezorganizarea nucleului şi condensarea cromatinei caracterizează:
- A.
Anafaza
- B.
Metafaza
- C.
Profaza
- D.
Telofaza
Correct Answer
C. ProfazaExplanation
During the prophase of cell division, the nucleus becomes disorganized and the chromatin condenses. This is necessary for the proper separation of genetic material during cell division. The condensation of chromatin allows the chromosomes to become more visible and easier to manipulate. Additionally, the disorganization of the nucleus helps to prepare the cell for the subsequent stages of cell division. Therefore, the correct answer is profaza.Rate this question:
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- 14.
Fusul de diviziune este:
- A.
Absent pe toată durata metafazei
- B.
Alcătuit din filamente care se pot contracta
- C.
Prezent în citoplasma neuronului
- D.
Situat, în anafază, în apropierea membranei nucleare
Correct Answer
B. Alcătuit din filamente care se pot contractaExplanation
The correct answer is "alcătuit din filamente care se pot contracta" (composed of filaments that can contract). This explanation states that the fusul de diviziune (spindle apparatus) is made up of filaments that have the ability to contract. This contraction is necessary for the separation of chromosomes during cell division.Rate this question:
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- 15.
Profaza mitozei se caracterizează prin:
- A.
Dezorganizarea membranei nucleare
- B.
Organizarea nucleolilor
- C.
Dezorganizarea fusului de diviziune
- D.
Organizarea plăcii ecuatoriale
Correct Answer
A. Dezorganizarea membranei nucleareExplanation
During prophase of mitosis, the nuclear membrane breaks down, allowing the genetic material to be accessible for further division. This allows the chromosomes to condense and become visible. Therefore, the correct answer is "dezorganizarea membranei nucleare" which means "disorganization of the nuclear membrane" in English.Rate this question:
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- 16.
Cromozomii sunt:
- A.
Bicromatidici în anafaza II
- B.
Monocromatidici în telofaza I
- C.
Tetrade cromatidice în metafaza I
- D.
Monocromatidici în profază
Correct Answer
C. Tetrade cromatidice în metafaza IExplanation
The correct answer is "tetrade cromatidice în metafaza I." In meiosis, tetrads are formed during prophase I, which consists of two homologous chromosomes, each composed of two sister chromatids. These tetrads align at the metaphase plate during metaphase I. Therefore, the statement that tetrads are present in metaphase I is accurate.Rate this question:
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- 17.
Celula mamă a unui ovul uman are:
- A.
2n = 46 cromozomi
- B.
N = 46 cromozomi
- C.
2n = 23 cromozomi
- D.
N = 23 cromozomi
Correct Answer
A. 2n = 46 cromozomiExplanation
The correct answer is 2n = 46 cromozomi. This means that the stem cell of a human egg has a diploid number (2n) of 46 chromosomes. This is the normal number of chromosomes in a human cell, with each chromosome existing in pairs. The diploid number is necessary for the proper functioning and development of the organism.Rate this question:
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- 18.
Cromozomii sunt bicromatidici în:
- A.
Telofaza mitozei
- B.
Profaza II
- C.
Anafaza mitozei
- D.
Telofaza II
Correct Answer
B. Profaza IIExplanation
During the second meiotic division, the chromosomes become bicromatidic in the prophase II. This means that each chromosome consists of two sister chromatids, which are held together by a centromere. In this phase, the nuclear envelope breaks down, and the spindle fibers start to form. The bicromatidic chromosomes then align along the equatorial plane of the cell, preparing for the separation of sister chromatids in the following stages of meiosis.Rate this question:
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- 19.
Prin diviziunea meiotică a unei celule cu 2n = 46 de cromozomi se formează în final celule-fiice cu:
- A.
2n = 46 cromozomi recombinaţi
- B.
N = 23 cromozomi bicromatidici
- C.
2n = 44 autozomi şi 2 heterozomi
- D.
N = 23 cromozomi monocromatidici
Correct Answer
D. N = 23 cromozomi monocromatidiciExplanation
During meiotic division, a cell with 2n = 46 chromosomes undergoes a reduction in the number of chromosomes. This results in the formation of daughter cells with n = 23 chromosomes, which are monocromatidic, meaning that each chromosome is composed of a single chromatid. This is the correct answer because it accurately describes the outcome of meiotic division in terms of chromosome number and structure.Rate this question:
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- 20.
La sfârşitul meiozei II, dintr-o celulă 2n = 16 cromozomi rezultă:
- A.
Două celule diploide cu 2n = 8
- B.
Patru celule haploide cu n = 8
- C.
Două celule haploide cu cromozomi recombinaţi
- D.
Patru celule diploide cu n = 8
Correct Answer
B. Patru celule haploide cu n = 8Explanation
At the end of meiosis II, from a cell with 2n = 16 chromosomes, four haploid cells with n = 8 chromosomes are formed. Meiosis II is the second division in meiosis, which follows meiosis I. During meiosis II, the sister chromatids separate, resulting in the formation of four haploid cells. Each of these cells contains half the number of chromosomes as the original cell, which is n = 8 in this case. Therefore, the correct answer is "patru celule haploide cu n = 8."Rate this question:
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- 21.
Fenomenul de crossing-over se realizează în:
- A.
Metafaza mitozei
- B.
Profaza I
- C.
Metafaza I
- D.
Telofaza II
Correct Answer
B. Profaza IExplanation
The correct answer is "profaza I". During prophase I of meiosis, homologous chromosomes pair up and exchange genetic material through a process called crossing-over. This genetic recombination results in the shuffling of genetic information between the chromosomes, increasing genetic diversity. Therefore, prophase I is the stage where crossing-over occurs.Rate this question:
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- 22.
Fiecare dintre celulele-fiice, formate prin diviziunea mitotică a unei celule-mamă cu 2n = 10 cromozomi, are:
- A.
N = 10 cromozomi
- B.
N = 5 cromozomi
- C.
2n = 5 cromozomi
- D.
2n = 10 cromozomi
Correct Answer
D. 2n = 10 cromozomiExplanation
Each daughter cell formed by mitotic division of a mother cell with 2n = 10 chromosomes will have 2n = 10 chromosomes.Rate this question:
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- 23.
Fiecare celulă rezultată din mitoza unei celule mamă cu 2n = 46 de cromozomi, prezintă:
- A.
2n = 23 cromozomi
- B.
N = 23 cromozomi
- C.
2n = 46 cromozomi
- D.
N = 46 cromozomi
Correct Answer
C. 2n = 46 cromozomiExplanation
Each cell resulting from the mitosis of a mother cell with 2n = 46 chromosomes will have 2n = 46 chromosomes. This means that each daughter cell will have the same number of chromosomes as the mother cell, which is 46. The "2n" notation represents the diploid number of chromosomes, indicating that the cells have two sets of chromosomes.Rate this question:
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- 24.
Metafaza meiozei se caracterizează prin:
- A.
Formarea tetradelor
- B.
Dezorganizarea nucleului
- C.
Realizarea crossing-over-ului
- D.
Formarea plăcii ecuatoriale
Correct Answer
D. Formarea plăcii ecuatorialeExplanation
In the metaphase of meiosis, the chromosomes align at the center of the cell in a single file formation called the metaphase plate or equatorial plate. This is known as the formation of the equatorial plate. The equatorial plate ensures that each daughter cell receives the correct number of chromosomes during cell division. The other options mentioned, such as the formation of tetrads, the disorganization of the nucleus, and the realization of crossing-over, do not occur specifically in the metaphase of meiosis.Rate this question:
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- 25.
Fiecare din celulele-fiice, rezultate din diviziunea meiotică a unei celule-mamă cu 2n = 28 cromozomi, are:
- A.
2n = 14 cromozomi
- B.
2n = 28 cromozomi
- C.
N = 14 cromozomi
- D.
N = 28 cromozomi
Correct Answer
C. N = 14 cromozomiExplanation
Each daughter cell resulting from the meiotic division of a mother cell with 2n = 28 chromosomes will have n = 14 chromosomes. Meiotic division is a type of cell division that reduces the number of chromosomes in the daughter cells by half. In this case, since the mother cell has 2n = 28 chromosomes, the daughter cells will have n = 14 chromosomes each.Rate this question:
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- 26.
Meioza se finalizează cu formarea a:
- A.
Două celule diploide
- B.
Două celule haploide
- C.
Patru celule diploide
- D.
Patru celule haploide
Correct Answer
D. Patru celule haploideExplanation
Meioza este un proces de diviziune celulară care are loc în celulele reproductive și duce la formarea de celule haploide. În acest proces, o celulă diploidă se divide în două etape succesive, rezultând patru celule fiice haploide. Aceste celule haploide conțin jumătate din numărul normal de cromozomi și sunt utilizate în reproducerea sexuală pentru a forma gameți (spermatozoizi sau ovule). Prin urmare, răspunsul corect este "patru celule haploide".Rate this question:
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- 27.
Profaza I se caracterizează prin:
- A.
Dezorganizarea fusului de diviziune
- B.
Despiralizarea cromozomilor
- C.
Refacerea membranei nucleare
- D.
împerecherea cromozomilor omologi
Correct Answer
D. împerecherea cromozomilor omologiExplanation
During the Profase I stage of meiosis, homologous chromosomes pair up and form structures called bivalents or tetrads. This pairing process is known as synapsis and is essential for the exchange of genetic material between homologous chromosomes through a process called crossing over. This allows for genetic variation and ensures the proper distribution of chromosomes during cell division. Therefore, the correct answer is "împerecherea cromozomilor omologi" which translates to "pairing of homologous chromosomes".Rate this question:
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- 28.
În interfază are loc:
- A.
Condensarea maximă a cromatinei
- B.
Dispariţia membranei nucleare
- C.
Dublarea cantităţii de ADN prin replicaţie
- D.
Separarea cromatidelor prin clivare
Correct Answer
C. Dublarea cantităţii de ADN prin replicaţieExplanation
In the interface phase of the cell cycle, the DNA undergoes replication, which leads to the doubling of the amount of DNA in the cell. This is an essential step in cell division as each daughter cell needs to have a complete set of genetic material. During replication, the DNA strands separate, and each strand serves as a template for the synthesis of a new complementary strand. This process ensures that each daughter cell receives an identical copy of the genetic material. Therefore, the correct answer is the "dublarea cantităţii de ADN prin replicaţie" or "doubling of the amount of DNA through replication".Rate this question:
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- 29.
Individualizarea cromozomilor are loc în:
- A.
Telofază
- B.
Profază
- C.
Metafază
- D.
Anafază
Correct Answer
B. ProfazăExplanation
During prophase, the chromosomes condense and become visible under a microscope. The nuclear envelope also starts to break down, allowing the chromosomes to move freely in the cell. This is the stage where the individualization of chromosomes occurs, as they become distinct and separate structures within the cell. Therefore, the correct answer is prophase.Rate this question:
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- 30.
Cromozomii se despiralizează în:
- A.
Telofază
- B.
Profază
- C.
Metafază
- D.
Anafază
Correct Answer
A. TelofazăExplanation
During telophase, the chromosomes start to decondense and unwind, returning to their extended form. This is the final stage of mitosis, where the nuclear envelope reforms around each set of chromosomes, and the nucleolus reappears. The spindle fibers disassemble, and the cell starts to undergo cytokinesis, dividing into two daughter cells.Rate this question:
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- 31.
Telofaza mitotică se caracterizează prin:
- A.
Formarea membranei nucleare
- B.
Despărţirea cromatidelor cromozomilor
- C.
Organizarea fusului de diviziune
- D.
Individualizarea cromozomilor
Correct Answer
A. Formarea membranei nucleareExplanation
Telofaza mitotică se caracterizează prin formarea membranei nucleare. Aceasta este etapa finală a diviziunii celulare, în care membranele nucleare se reasamblează în jurul noilor seturi de cromozomi formate în timpul anafazei. Această reasamblare a membranelor nucleare este crucială pentru a separa conținutul nuclear de restul celulei și pentru a restabili compartimentarea celulară.Rate this question:
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- 32.
Centrozomul:
- A.
Este alcătuit din formaţiuni numite centrioli
- B.
Prezintă la periferie o membrană dublă
- C.
Conţine enzime cu rol în digestia intracelulară
- D.
Este format dintr-o subunitate mare şi una mică
Correct Answer
A. Este alcătuit din formaţiuni numite centrioliExplanation
The correct answer is "este alcătuit din formaţiuni numite centrioli" because the given statement directly corresponds to the information provided in the question. It states that the centrozomul is composed of structures called centrioli, which matches the information given in the question.Rate this question:
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- 33.
Anafaza mitotică se caracterizează prin:
- A.
Formarea membranei nucleare
- B.
Migrarea cromozomilor monocromatidici spre poli
- C.
Dezorganizarea fusului de diviziune
- D.
Individualizarea cromozomilor bicromatidici
Correct Answer
B. Migrarea cromozomilor monocromatidici spre poliExplanation
During anaphase of mitosis, the chromosomes, which consist of two sister chromatids, migrate towards opposite poles of the cell. This is facilitated by the shortening of the microtubules that make up the spindle fibers, pulling the chromatids apart. As a result, each pole of the cell receives one copy of each chromosome, ensuring that each daughter cell will have a complete set of chromosomes. This process is essential for the proper distribution of genetic material during cell division. The other options mentioned, such as the formation of the nuclear membrane, disorganization of the spindle fibers, and individualization of the bicromatidic chromosomes, are not characteristic of anaphase.Rate this question:
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- 34.
Nucleolii se dezorganizează în:
- A.
Metafaza II
- B.
Anafaza meiozei I
- C.
Telofaza I
- D.
Profaza mitozei
Correct Answer
D. Profaza mitozeiExplanation
During the prophase of mitosis, the nucleoli, which are responsible for producing ribosomes, disorganize. This is because the prophase is the first stage of mitosis, where the nuclear envelope breaks down, and the chromatin condenses into visible chromosomes. As a result, the nucleoli become dispersed and lose their distinct structure.Rate this question:
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