Cellular processes
Use of Energy and Materials for Cellular Processes:
Cell division is one of the periods upon which cell growth thrives. It is the basis of reproducing and renewing cells from a parent cell or damaged cell-an immense beneficiary for all organisms.
ESSENTIAL ROLES OF CELL DIVISION
- Reproduction/procreation
- Transferring of genetic material from generation to generation
- Renewal and repair of damaged cells
Cellular processes such as interphase, mitosis, cytokinesis and meiosis all manage cell division.
Cell division is one of the periods upon which cell growth thrives. It is the basis of reproducing and renewing cells from a parent cell or damaged cell-an immense beneficiary for all organisms.
ESSENTIAL ROLES OF CELL DIVISION
- Reproduction/procreation
- Transferring of genetic material from generation to generation
- Renewal and repair of damaged cells
Cellular processes such as interphase, mitosis, cytokinesis and meiosis all manage cell division.
THE CELL CYCLE
Interphase
-Interphase is a phase commonly responsible for ninety percent of the cell cycle. It is during interphase that most of a cell’s growth occurs, and when most chromosomal copying happens. This phase is an introduction for the cell to prepare for cell division.
“In many tissues, such as in the brain, most mature cells will remain in interphase throughout their lives”
- www.biology.uoregon.edu -
-Interphase is divided into subphases:
-G1 phase, known as the “first gap”
-S phase, known as “synthesis”
-G2 phase, known as the “second gap”
(during all of which the cell produces proteins and important organelles)
-In more specific terms, G1 is the phase where a majority of the cell’s growth occurs, S is the phase where the cell makes copies of its chromosomes, and G2 is the phase where the cell prepares for cellular division.
-Interphase leads the cell into mitosis (the M gap in interphase terms)
Interphase
-Interphase is a phase commonly responsible for ninety percent of the cell cycle. It is during interphase that most of a cell’s growth occurs, and when most chromosomal copying happens. This phase is an introduction for the cell to prepare for cell division.
“In many tissues, such as in the brain, most mature cells will remain in interphase throughout their lives”
- www.biology.uoregon.edu -
-Interphase is divided into subphases:
-G1 phase, known as the “first gap”
-S phase, known as “synthesis”
-G2 phase, known as the “second gap”
(during all of which the cell produces proteins and important organelles)
-In more specific terms, G1 is the phase where a majority of the cell’s growth occurs, S is the phase where the cell makes copies of its chromosomes, and G2 is the phase where the cell prepares for cellular division.
-Interphase leads the cell into mitosis (the M gap in interphase terms)
Cell Growth and Division (Mitosis)
- MITOSIS
-Mitosis is a process involving the division of the nucleus and the reproduction of two daughter cells from one parent cell (and that have the exact genetic material).
-Mitosis is divided into five essential phases that help the cell divide in specific sequence: prophase, prometaphase, metaphase, anaphase and telophase.
PROPHASE
-DNA condenses into chromosomes
-The nuclear membrane breaks down
-Microtubules and centrosomes in the cytoplasm form the mitotic spindle
-Centrosomes spread across the cytoplasm, extending the spindle farther across the cell
PROMETAPHASE
-Nuclear casing begins to fragment and thin
-Microtubules spread into the nuclear area
-The chromosomes have become more condensed and have developed kinetochores at their centromeres
-The microtubules still yet unattached to kinetochores interact with those of the opposite pole
METAPHASE
~Metaphase is the longest lasting phase within mitosis~
-By now, centrosomes have fully formed at opposite poles of the cell
-Centromeres of the chromosomes line up along the metaphase plate-an imaginary plate that is equidistant between the two poles-and all microtubules attach to the center of the kinetochores and microtubules of the opposite pole
ANAPHASE
~Unlike metaphase, anaphase is the shortest phase within mitosis~
-One key step of the initiation of anaphase is the cleaving of cohesin proteins-circular proteins lining the inner sides of the sister chromatids. Now each chromatid has become a fully developed and whole chromosome
-The newly formed individual chromatids move to opposite poles of their previous sister
-Though the kinetochore microtubules shorten, the cell lengthens due to the elongating of the non-kinetochore tubules
-By the end of this phase, both poles have an equal number of chromosomes
TELOPHASE
-Telophase is the phase where the two new daughter nuclei form in the cell
-Nuclear envelopes develop from fragments of that of the parent’s cell
-The chromosomes become more separated
-Mitosis is complete!
The difference between Mitotic and Meiotic processes
Cell Growth and Division (Meiosis)
*Rather than how mitosis was used to replicate damaged or new cells, meiosis is used to form gametes, or reproductive cells.
-Meiosis reduces the number of sets of chromosomes from two to one in these reproductive cells-from diploid to haploid sets.
-Much like mitosis, meiosis involves a replication of chromosomes right before the process takes place; Meiosis differs, however, in that it has two cycles rather than one in order to divide into four haploid daughter cells (each with half the number of chromosomes as their parent.)
Simple Rundown of Meiosis:
-Meiosis has the same phases as mitosis, but since there are two cycles within meiosis, there are also two phases of each individual mitotic phase.
-Meiosis begins in interphase, with one homologous pair of chromosomes (diploid) in the parent cell that is soon replicated to become a set of duplicated sister chromatids.
-From interphase, prophase I, along with the other mitotic phases (followed by roman numerals) takes place, only this time there has been an advancement-crossing over has to occur.
*Crossing over is the exchange of equivalent pieces of DNA by non-sister chromatids, and allows the chromosomes to look much more condensed in the process. Metaphase I, Anaphase I and Telophase I follow, and they show the crossed-over homologous pairs transferring DNA segments and preparing for meiosis II.
-From this diploid parent cell, the homologous chromosomes separate into two haploid cells with replicated chromosomes-this is known as meiosis I.
-Meiosis I transitions into meiosis II by separating the sister chromatids into another pair for each haploid cell, therefore having four haploid cells created from the two haploids with replicated chromosomes.
-There are now four haploid daughter cells as a result from one diploid parent cell, all with various crossed-over segments of non-sister DNA and the process of meiosis is complete!
-Meiosis reduces the number of sets of chromosomes from two to one in these reproductive cells-from diploid to haploid sets.
-Much like mitosis, meiosis involves a replication of chromosomes right before the process takes place; Meiosis differs, however, in that it has two cycles rather than one in order to divide into four haploid daughter cells (each with half the number of chromosomes as their parent.)
Simple Rundown of Meiosis:
-Meiosis has the same phases as mitosis, but since there are two cycles within meiosis, there are also two phases of each individual mitotic phase.
-Meiosis begins in interphase, with one homologous pair of chromosomes (diploid) in the parent cell that is soon replicated to become a set of duplicated sister chromatids.
-From interphase, prophase I, along with the other mitotic phases (followed by roman numerals) takes place, only this time there has been an advancement-crossing over has to occur.
*Crossing over is the exchange of equivalent pieces of DNA by non-sister chromatids, and allows the chromosomes to look much more condensed in the process. Metaphase I, Anaphase I and Telophase I follow, and they show the crossed-over homologous pairs transferring DNA segments and preparing for meiosis II.
-From this diploid parent cell, the homologous chromosomes separate into two haploid cells with replicated chromosomes-this is known as meiosis I.
-Meiosis I transitions into meiosis II by separating the sister chromatids into another pair for each haploid cell, therefore having four haploid cells created from the two haploids with replicated chromosomes.
-There are now four haploid daughter cells as a result from one diploid parent cell, all with various crossed-over segments of non-sister DNA and the process of meiosis is complete!
CYTOKINESIS
*Cytokinesis involves the final separation of the parent cell with two nuclei into two daughter cells each with their own nucleus.
-Most of the separating has been accomplished in telophase, so the final cleaving is the responsibility of cytokinesis
~In Animal Cells- cytokinesis involves the formation of the cleavage furrow, which pinches the cell into the two final daughter cells~
www.phschool.com
www.student.ccbcmd.edu
www.dnaftb.org
*Cytokinesis involves the final separation of the parent cell with two nuclei into two daughter cells each with their own nucleus.
-Most of the separating has been accomplished in telophase, so the final cleaving is the responsibility of cytokinesis
~In Animal Cells- cytokinesis involves the formation of the cleavage furrow, which pinches the cell into the two final daughter cells~
www.phschool.com
www.student.ccbcmd.edu
www.dnaftb.org
Maintaining Homeostasis (Cellular Respiration and Photosynthesis)
- *Homeostasis is a steady or balanced state that calls for a generally constant internal environment regardless of external changes.
Daily occurrences of homeostasis in humans:
-Taking one’s temperature- the constant temperature should be 98.6 degrees Fahrenheit (or 37 degrees Celsius)
-Glucose regulating so as to control the concentration of glucose in the bloodstream
-pH levels of bloodstream should also be kept within a 0.1 difference from 7.4 units- controlling intakes of acidic foods
Applying Photosynthesis to Homeostasis:
*Photosynthesis is the conversion process regarding the chemical energy plants, more specifically a plant’s chloroplasts, store in sugars and organic molecules. Plants capture the sun’s energy and in turn convert it to this chemical energy found in their food source.
-Photosynthesis can be applied to maintaining homeostasis in humans as well as in plants: light, water, nutrients, and temperature
www.factorsofphotosynthesis.blogspot.com
*Photosynthesis is the conversion process regarding the chemical energy plants, more specifically a plant’s chloroplasts, store in sugars and organic molecules. Plants capture the sun’s energy and in turn convert it to this chemical energy found in their food source.
-Photosynthesis can be applied to maintaining homeostasis in humans as well as in plants: light, water, nutrients, and temperature
www.factorsofphotosynthesis.blogspot.com
-In humans, there is a set point around which things are regulated-points that fluctuate around this set point are known as stimulus. Based on this stimulus, the body responds by trying to return to the constant and comfortable set point.
CELLULAR RESPIRATION IN RELATION TO HOMEOSTASIS
*Cellular respiration is a process where oxygen is consumed as a reactant along with organic compounds (most commonly glucose), and a process that disposes of carbon dioxide, water and energy.
-Cellular respiration as a process itself is much like maintaining homeostasis, in that it removes the waste that is disturbing the balance of the organism, but also allows for an essential nutrient, oxygen, to filter through.
www.phschool.com
-Cellular respiration, in terms of removing the waste and allowing the essentials to come through, is also very important in other systems throughout the human body.
-In the respiratory system, for example, there is an organ called alveoli that is within the lungs, and it is the regulator of oxygen that passes through the body. As the bloodstream passes around the alveoli, it takes the oxygen-rich blood and passes it along throughout the rest of the system, while also diffusing the carbon dioxide out of the bloodstream. This is just one of the many systems that uses cellular respiration to maintain an internal balance where nutrients are involved.
www.mhhe.com
*Cellular respiration is a process where oxygen is consumed as a reactant along with organic compounds (most commonly glucose), and a process that disposes of carbon dioxide, water and energy.
-Cellular respiration as a process itself is much like maintaining homeostasis, in that it removes the waste that is disturbing the balance of the organism, but also allows for an essential nutrient, oxygen, to filter through.
www.phschool.com
-Cellular respiration, in terms of removing the waste and allowing the essentials to come through, is also very important in other systems throughout the human body.
-In the respiratory system, for example, there is an organ called alveoli that is within the lungs, and it is the regulator of oxygen that passes through the body. As the bloodstream passes around the alveoli, it takes the oxygen-rich blood and passes it along throughout the rest of the system, while also diffusing the carbon dioxide out of the bloodstream. This is just one of the many systems that uses cellular respiration to maintain an internal balance where nutrients are involved.
www.mhhe.com