Podcast
Questions and Answers
Human nerve cells stop increasing in number by the second year of life and never regain the ability to ______.
Human nerve cells stop increasing in number by the second year of life and never regain the ability to ______.
divide
Most cells in the liver stop multiplying when it reaches its final size around the time of ______.
Most cells in the liver stop multiplying when it reaches its final size around the time of ______.
puberty
The cell division is also known as the ______.
The cell division is also known as the ______.
CELL CYCLE
During the G1 phase, the major event is ______ synthesis.
During the G1 phase, the major event is ______ synthesis.
Signup and view all the answers
During the S phase, the major activity is ______ replication.
During the S phase, the major activity is ______ replication.
Signup and view all the answers
At the end of the S phase, all the chromosomes become pairs of identical sister ______.
At the end of the S phase, all the chromosomes become pairs of identical sister ______.
Signup and view all the answers
Mitosis distributes the genetic material into two equal sets in two daughter ______.
Mitosis distributes the genetic material into two equal sets in two daughter ______.
Signup and view all the answers
Cells that stop dividing, like nerve cells, are arrested in the G1 phase and may enter the ______ phase.
Cells that stop dividing, like nerve cells, are arrested in the G1 phase and may enter the ______ phase.
Signup and view all the answers
The G1, S and G2 phases are collectively called ______ because these are the preparatory stages between two mitoses.
The G1, S and G2 phases are collectively called ______ because these are the preparatory stages between two mitoses.
Signup and view all the answers
The M phase or mitosis itself consists of 4 phases – PROPHASE, METAPHASE, ANAPHASE and ______.
The M phase or mitosis itself consists of 4 phases – PROPHASE, METAPHASE, ANAPHASE and ______.
Signup and view all the answers
During prophase, the chromosomes do not look doubled due to the still presence of the ______.
During prophase, the chromosomes do not look doubled due to the still presence of the ______.
Signup and view all the answers
The arrangement of sister chromatid pairs to the equatorial plane of the cell is called the ______.
The arrangement of sister chromatid pairs to the equatorial plane of the cell is called the ______.
Signup and view all the answers
The separation of sister chromatids starts at the phase of ______ and progresses.
The separation of sister chromatids starts at the phase of ______ and progresses.
Signup and view all the answers
The constriction around the equator of the cell called ______ initiates during telophase.
The constriction around the equator of the cell called ______ initiates during telophase.
Signup and view all the answers
A nuclear envelope starts to form around the daughter chromosomes during ______.
A nuclear envelope starts to form around the daughter chromosomes during ______.
Signup and view all the answers
When nuclear envelope formation is finished, this process is called ______.
When nuclear envelope formation is finished, this process is called ______.
Signup and view all the answers
In plant mitosis, cleavage furrow does not form; instead, a ______ forms between the two daughter cells.
In plant mitosis, cleavage furrow does not form; instead, a ______ forms between the two daughter cells.
Signup and view all the answers
Asexual reproduction in unicellular organisms is equivalent to ______.
Asexual reproduction in unicellular organisms is equivalent to ______.
Signup and view all the answers
In prokaryotes, asexual reproduction is known as ______.
In prokaryotes, asexual reproduction is known as ______.
Signup and view all the answers
Mitosis is a process that precedes cell division in unicellular ______.
Mitosis is a process that precedes cell division in unicellular ______.
Signup and view all the answers
______ is a form of asexual reproduction where offspring develop as outgrowths from the parent’s body.
______ is a form of asexual reproduction where offspring develop as outgrowths from the parent’s body.
Signup and view all the answers
When body parts that break off develop into new individuals, this process is called ______.
When body parts that break off develop into new individuals, this process is called ______.
Signup and view all the answers
The ability of a single cell from a plant to grow into a whole plant is referred to as ______.
The ability of a single cell from a plant to grow into a whole plant is referred to as ______.
Signup and view all the answers
The products of asexual reproduction mechanisms in nature are called ______.
The products of asexual reproduction mechanisms in nature are called ______.
Signup and view all the answers
In sexual reproduction, a new individual is produced by the contribution of two ______.
In sexual reproduction, a new individual is produced by the contribution of two ______.
Signup and view all the answers
Gametes differ from all other body cells, which are called ______ cells.
Gametes differ from all other body cells, which are called ______ cells.
Signup and view all the answers
The zygote that results from fertilization contains a mixture of ______ from the two parents.
The zygote that results from fertilization contains a mixture of ______ from the two parents.
Signup and view all the answers
The biological process by which haploid gametes are produced is called ______.
The biological process by which haploid gametes are produced is called ______.
Signup and view all the answers
Meiosis occurs only among specialized cells located in reproductive ______.
Meiosis occurs only among specialized cells located in reproductive ______.
Signup and view all the answers
Interphase of meiosis is essentially the same with Interphase of ______.
Interphase of meiosis is essentially the same with Interphase of ______.
Signup and view all the answers
Each of the meiotic divisions consists of the same four phases of cell division that occur in ______.
Each of the meiotic divisions consists of the same four phases of cell division that occur in ______.
Signup and view all the answers
Prophase I of meiosis is similar to the Prophase of ______.
Prophase I of meiosis is similar to the Prophase of ______.
Signup and view all the answers
In Prophase I of meiosis, homologous chromosomes come together in a process called ______.
In Prophase I of meiosis, homologous chromosomes come together in a process called ______.
Signup and view all the answers
The structure formed by the synaptic pairs, consisting of four sister chromatids, is called a ______.
The structure formed by the synaptic pairs, consisting of four sister chromatids, is called a ______.
Signup and view all the answers
During Prophase I, the exchange segments at points called ______ occurs.
During Prophase I, the exchange segments at points called ______ occurs.
Signup and view all the answers
In Metaphase I, the division of the centromere does not occur, leading to sister chromatids remaining ______.
In Metaphase I, the division of the centromere does not occur, leading to sister chromatids remaining ______.
Signup and view all the answers
Anaphase I of meiosis is similar to mitosis, but the sister ______ are still attached together.
Anaphase I of meiosis is similar to mitosis, but the sister ______ are still attached together.
Signup and view all the answers
Telophase I results in the formation of two ______ cells, each with half the number of chromosomes.
Telophase I results in the formation of two ______ cells, each with half the number of chromosomes.
Signup and view all the answers
A short rest period between the first and second meiotic divisions is called ______.
A short rest period between the first and second meiotic divisions is called ______.
Signup and view all the answers
The second meiotic division is similar to a mitotic ______ but occurs without Interphase.
The second meiotic division is similar to a mitotic ______ but occurs without Interphase.
Signup and view all the answers
During Prophase II, the nuclear envelope disintegrates and ______ chromatids become visible.
During Prophase II, the nuclear envelope disintegrates and ______ chromatids become visible.
Signup and view all the answers
During Metaphase II, the attachment of the spindle fibers to the ______ is completed.
During Metaphase II, the attachment of the spindle fibers to the ______ is completed.
Signup and view all the answers
In Anaphase II, sister chromatids are pulled apart and move towards the ______ of the cell.
In Anaphase II, sister chromatids are pulled apart and move towards the ______ of the cell.
Signup and view all the answers
Telophase II concludes with the completion of the nuclear membrane formation and further deepening of the ______ furrow.
Telophase II concludes with the completion of the nuclear membrane formation and further deepening of the ______ furrow.
Signup and view all the answers
In humans, there are 23 chromosome ______, leading to a high variability in gametes.
In humans, there are 23 chromosome ______, leading to a high variability in gametes.
Signup and view all the answers
Study Notes
Cell Division and Reproduction
- Some cells in multicellular organisms continue to grow and divide throughout life, while others stop dividing at some point in development.
- Examples include nerve cells, which stop dividing after the second year of life, and liver cells, which can resume dividing if less than 2/3 of the liver is removed.
- Cell division is a continuous process, the same in all eukaryotic cells (excluding gametes).
- This process is called the cell cycle.
- A 24-hour cell cycle includes 23 hours of preparatory stages (G1, S, and G2) and 1 hour of mitosis.
- The main event during the G1 phase of the cell cycle is protein synthesis, where the cell produces and prepares enzymes.
- The major activity during the S phase is DNA replication.
- During G2, the cell synthesizes final proteins and reaches its maximum size.
- Mitosis is the process where the genetic material divides into two equal sets in daughter nuclei.
- Cytokinesis is the division of the entire cell, producing two daughter cells with one nucleus each.
- Cells that naturally stop dividing are arrested at a point in the G1 phase (G0 phase).
- Cells can be arrested until they die (ex: nerve cells).
Mitosis
- Mitosis consists of four phases: Prophase, Metaphase, Anaphase, and Telophase.
- These phases do not have clear-cut boundaries.
- Prophase: chromosomes become visible (with disintegration of the nuclear envelope). Centrosomes migrate to opposite poles and form mitotic spindles.
- Metaphase: Chromosomes line up at the cell's equator (metaphase plate) with kinetochores attached to spindle fibers.
- Anaphase: Sister chromatids separate and move to opposite poles.
- Telophase: Chromosomes decondense, nuclear envelope reforms, and cytokinesis begins.
- Animal cells become spherical during metaphase.
Meiosis
- Meiosis produces haploid gametes, ensuring the maintenance of a constant chromosome number in species.
- Meiosis involves two divisions (Meiosis I and Meiosis II).
-
Meiosis I: Homologous chromosomes pair (synapse), forming tetrads, and exchange genetic material (crossing over). Homologous chromosomes separate, producing two haploid cells.
- Prophase I: Homologous chromosomes pair (synapse).
- Metaphase I: Homologous chromosomes align at the metaphase plate.
- Anaphase I: Homologous chromosomes separate.
- Telophase I: Chromosomes arrive at the poles; cytokinesis occurs; two haploid cells are formed
-
Meiosis II: Sister chromatids separate, producing four haploid cells. This is similar to mitosis.
- Prophase II: Nuclear envelope breaks down.
- Metaphase II: Chromosomes align at the metaphase plate.
- Anaphase II: Sister chromatids separate.
- Telophase II: Chromosomes arrive at the poles; cytokinesis occurs; four haploid cells are formed
- Animal/Plant meiosis differences: Plant cells do not become spherical during metaphase; new cells are separated by a cell plate instead of a cleavage furrow
- In humans this leads to 2^23 (=10 million) possible gamete combinations
- Crossing over leads to further variability of genetic make-up within the offspring
Asexual and Sexual Reproduction
- Reproduction is the ability to produce others of the same kind.
- Asexual reproduction: New individuals are formed from a single parent, producing genetically identical offspring (e.g., binary fission, budding, fragmentation, plant cloning)
- Sexual reproduction: Two parents contribute genetic material (gametes), creating variation in offspring.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the processes of cell division, including mitosis and the cell cycle. This quiz covers key phases such as G1, S, and G2, alongside important concepts related to cell growth and replication. Dive into the fascinating world of cell biology and see how well you understand these vital processes.
