Unit 4 covers cell communication, regulatory, mitosis, and cell cycles. The phosphorylation cascade and transduction are examples of system interactions. The cell signals carry information for activating genes and enzymes. Regulations by Kansas and cyclins are type of information in system interaction that guide the stages of cell cycle during mitosis. Mutations can occur during replication of DNA, which relates to evolution.
1. Describe the three stages of cell communication: reception, transduction, and response
- Reception: The signaling molecule from outside of the cell will bind to the receptor protein located in the cell surface, when the chemical signal can be detected by the target cell.
-Transduction: The binding of the signaling molecule changes the receptor protein. It takes several steps with relay molecules bring change to next one, which bring a specific cellular response.
-Response: The transferred signal triggers the specific cellular response, which active a cellular activity.
(1)Kph[http://kph12.myweb.uga.edu/cellcommuncation.html]
(2)Note[http://www.course-notes.org/Biology/Outlines/Chapter_11_Cell_Communication]
- Reception: The signaling molecule from outside of the cell will bind to the receptor protein located in the cell surface, when the chemical signal can be detected by the target cell.
-Transduction: The binding of the signaling molecule changes the receptor protein. It takes several steps with relay molecules bring change to next one, which bring a specific cellular response.
-Response: The transferred signal triggers the specific cellular response, which active a cellular activity.
(1)Kph[http://kph12.myweb.uga.edu/cellcommuncation.html]
(2)Note[http://www.course-notes.org/Biology/Outlines/Chapter_11_Cell_Communication]
2. Explain how G protein-coupled receptors receive cell signals and start transduction
- After the signaling molecule binds to G protein-coupled receptors, the activated G protein-coupled receptors bind to an inactive G protein. It caused the GTP to displace GDP, which activate the G protein. Then the G protein binds to a specific enzyme and activates it, which triggers the step of transduction.
(1) Nature[http://www.nature.com/nature/focus/gpcrs/]
(2) Ncbi[http://www.ncbi.nlm.nih.gov/books/NBK21718/]
- After the signaling molecule binds to G protein-coupled receptors, the activated G protein-coupled receptors bind to an inactive G protein. It caused the GTP to displace GDP, which activate the G protein. Then the G protein binds to a specific enzyme and activates it, which triggers the step of transduction.
(1) Nature[http://www.nature.com/nature/focus/gpcrs/]
(2) Ncbi[http://www.ncbi.nlm.nih.gov/books/NBK21718/]
3. Explain how receptor tyrosine kinases receive cell signals and start transduction
- After the signaling molecule binds to receptor tyrosine kinases, two receptors binds together to form an activated dimer. Each tyrosine kinases adds a phosphate from ATP, and the specific relay proteins bind to specific phosphorylated tyrosine. Then each activated protein will trigger the step of transduction.
(1)Ncbi[http://www.ncbi.nlm.nih.gov/pubmed/22879068]
(2)Sino[http://www.sinobiological.com/Receptor-Tyrosine-Kinase-a-516.html]
- After the signaling molecule binds to receptor tyrosine kinases, two receptors binds together to form an activated dimer. Each tyrosine kinases adds a phosphate from ATP, and the specific relay proteins bind to specific phosphorylated tyrosine. Then each activated protein will trigger the step of transduction.
(1)Ncbi[http://www.ncbi.nlm.nih.gov/pubmed/22879068]
(2)Sino[http://www.sinobiological.com/Receptor-Tyrosine-Kinase-a-516.html]
4. Generalize how a cell signal is amplified by a phosphorylation cascade
- In a phosphorylation cascade, a signal activate the relay protein kinase. Then the active protein kinase will transfer a phosphate from ATP to active another protein kinase and so on. At each step, there is an amplification of the original signal to make the small initial signal become a large response.
(1) Rpi[http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/signals.htm]
(2) Ata[http://ataxiatelangiectasia.wikispaces.com/Phosphorylation+Cascade]
- In a phosphorylation cascade, a signal activate the relay protein kinase. Then the active protein kinase will transfer a phosphate from ATP to active another protein kinase and so on. At each step, there is an amplification of the original signal to make the small initial signal become a large response.
(1) Rpi[http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/signals.htm]
(2) Ata[http://ataxiatelangiectasia.wikispaces.com/Phosphorylation+Cascade]
5. Identify how a cell response in the nucleus turns on genes, whereas in the cytoplasm it activates enzymes
- After the last enzyme is activated, it will enter the nucleus and activates a gene-regulating protein, a transcription factor. This protein can turn on the gene.
(1) Cell[http://www.cellsignal.com/reference/landscapes/nucleus.html]
(2) Nature [http://www.nature.com/nrm/posters/signalling/index.html]
- After the last enzyme is activated, it will enter the nucleus and activates a gene-regulating protein, a transcription factor. This protein can turn on the gene.
(1) Cell[http://www.cellsignal.com/reference/landscapes/nucleus.html]
(2) Nature [http://www.nature.com/nrm/posters/signalling/index.html]
6. Specify what apoptosis means and why it is important to normal functioning of multicellular organisms.
Apoptosis means a program of controlled cell suicide. In the multicellular organisms, If the cell is damaged or diseased, apoptosis can process the cell to death.
(1) Evo[http://www.evolutionofcomputing.org/Multicellular/Apoptosis.html]
(2) Ncbi[http://www.ncbi.nlm.nih.gov/books/NBK26873/]
Apoptosis means a program of controlled cell suicide. In the multicellular organisms, If the cell is damaged or diseased, apoptosis can process the cell to death.
(1) Evo[http://www.evolutionofcomputing.org/Multicellular/Apoptosis.html]
(2) Ncbi[http://www.ncbi.nlm.nih.gov/books/NBK26873/]
7. Describe the structure of the duplicated chromosome
- The duplicated chromosome is looked like X. It consist of two sister chromatids attached together at a point called the centromere.
(1) Mcb[http://cyberbridge.mcb.harvard.edu/mitosis_2.html]
(2) Rcn[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Chromosomes.html]
- The duplicated chromosome is looked like X. It consist of two sister chromatids attached together at a point called the centromere.
(1) Mcb[http://cyberbridge.mcb.harvard.edu/mitosis_2.html]
(2) Rcn[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Chromosomes.html]
8.Summarize the cell cycle and stages of mitosis
The interphase of cell cycle has G1 for cell growth, S phase for DNA replication, G2 for cell growth. Then the M phase includes Mitosis for the division of nucleus and Cytokinesis for dividing cytoplasm and producing two daughter cells.
Mitosis has five stages: Prophase (the chromatin condenses into a chromosome), Metaphase (chromosomes line up in the middle of the cell), Anaphase (chromosomes separate), Telophase (reforms of two cells), Cytokinesis (the cell membrane splits to form two new compete cells).
(1)Rcn[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellCycle.html]
(2)Joh [http://www.johnkyrk.com/mitosis.html]
The interphase of cell cycle has G1 for cell growth, S phase for DNA replication, G2 for cell growth. Then the M phase includes Mitosis for the division of nucleus and Cytokinesis for dividing cytoplasm and producing two daughter cells.
Mitosis has five stages: Prophase (the chromatin condenses into a chromosome), Metaphase (chromosomes line up in the middle of the cell), Anaphase (chromosomes separate), Telophase (reforms of two cells), Cytokinesis (the cell membrane splits to form two new compete cells).
(1)Rcn[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellCycle.html]
(2)Joh [http://www.johnkyrk.com/mitosis.html]
9. Explain the role of kinases and cyclin in the regulation of the cell cycle
- Kinase are enzyme protein that regulate the ell cycle. The kinase can be activated when bind to the cyclin. This kinases called cyclin-dependent kinases(Cdks). The Cdks can give go-ahead signals at G1 and G2 checkpoints.
(1 )Ncbi[http://www.ncbi.nlm.nih.gov/pubmed/7711288]
(2) Plant[http://www.plantcell.org/content/11/4/509.full]
- Kinase are enzyme protein that regulate the ell cycle. The kinase can be activated when bind to the cyclin. This kinases called cyclin-dependent kinases(Cdks). The Cdks can give go-ahead signals at G1 and G2 checkpoints.
(1 )Ncbi[http://www.ncbi.nlm.nih.gov/pubmed/7711288]
(2) Plant[http://www.plantcell.org/content/11/4/509.full]
10.Discuss the role of mitosis in the distribution of genetic information
The product of mitosis are two identical daughter cells carried same genetic information as the parent cell due to DNA replication.
(1) Nwc[http://www.newworldencyclopedia.org/entry/mitosis]
(2) Wik[http://mitosis.wikidot.com/lzimmermann-function-of-mitosis]
The product of mitosis are two identical daughter cells carried same genetic information as the parent cell due to DNA replication.
(1) Nwc[http://www.newworldencyclopedia.org/entry/mitosis]
(2) Wik[http://mitosis.wikidot.com/lzimmermann-function-of-mitosis]
In Unit 4, We learned that signaling is used between cells such as between mating yeast and between nerve cells to stimulate the target cell. Signaling is also used inside the cell to regulate transcription and cytoplasmic activities. Cell division, known as mitosis, is important to understand because it is used in reproduction, growth and development, and in tissue renewal. Loss of cell cycle control can lead to growth of tumor. Growth factor can be used to regulate the cell cycle signal.
Vocabulary (Chapter 11-12)
1. Signal transduction pathway is a series of steps by which a signal on a cell’s surface is converted into a specific cellular response
2.Ligand-gated ion channel receptor acts as a gate when the receptor changes shape
3.Second messengers are small, nonprotein, water-soluble molecules or ions that spread throughout a cell by diffusion
4.Scaffolding proteins are large relay proteins to which other relay proteins are attached
5.Kinetochores are protein complexes associated with centromeres
6.MPF (maturation-promoting factor) is a cyclin-Cdk complex that triggers a cell’s passage past the G2 checkpoint into the M phase
7.G0 phase occurs when the cell does not receive the go-ahead signal, it will exit the cycle, switching into a nondividing state.
8. Centromere is the narrow “waist” of the duplicated chromosome, where the two chromatids are most closely attached
9.Mitotic spindle is a structure made of microtubules that controls chromosome movement during mitosis
10.Chiasmata is X-shaped regions where crossing over occurred
1. Signal transduction pathway is a series of steps by which a signal on a cell’s surface is converted into a specific cellular response
2.Ligand-gated ion channel receptor acts as a gate when the receptor changes shape
3.Second messengers are small, nonprotein, water-soluble molecules or ions that spread throughout a cell by diffusion
4.Scaffolding proteins are large relay proteins to which other relay proteins are attached
5.Kinetochores are protein complexes associated with centromeres
6.MPF (maturation-promoting factor) is a cyclin-Cdk complex that triggers a cell’s passage past the G2 checkpoint into the M phase
7.G0 phase occurs when the cell does not receive the go-ahead signal, it will exit the cycle, switching into a nondividing state.
8. Centromere is the narrow “waist” of the duplicated chromosome, where the two chromatids are most closely attached
9.Mitotic spindle is a structure made of microtubules that controls chromosome movement during mitosis
10.Chiasmata is X-shaped regions where crossing over occurred