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Cell Biology
I have some short questions-
i) Wikipedia says that dynamic instability is the coexistence of assembly and disassembly at the ends of a microtubule. But according to Gerald Karp it is the coexistance of assembly and disassembly of microtuble at its plus end only. I also agree with the latter for at the minus end the GTP is not hydrolysed. What do you think is correct?
ii) Does microtubules act as scaffold for attachment of cell organelles to maintain their positions within a cell?
i) Wikipedia says that dynamic instability is the coexistence of assembly and disassembly at the ends of a microtubule. But according to Gerald Karp it is the coexistance of assembly and disassembly of microtuble at its plus end only. I also agree with the latter for at the minus end the GTP is not hydrolysed. What do you think is correct?
ii) Does microtubules act as scaffold for attachment of cell organelles to maintain their positions within a cell?
Cell Biology
What is nucleation of microtubule?
If you could explain in simple words it would be of great help.
If you could explain in simple words it would be of great help.
Cell Biology
Why does ATP contain such a large amount of energy?
(please leave a more understandable answer for the lesser scientific mind please)
(please leave a more understandable answer for the lesser scientific mind please)
Cell Biology
Briefly describe the cellular changes that occur in melanoma. Explain how the loss of normal control mechanisms, such as uncontrolled cell growth can result in melanoma.
Cell Biology
At the beginning of cellular respiration, all NAD+ are already reduced. True or false?
Cell Biology
What would happen to a cell that lacked p53 ?
Cell Biology
64.
Each eukaryotes can regulate gene expression. Determine which of the five mechanisms each example represents. Not all examples will be used.
changes in chromatin structure Activity of transcription apparatus RNA processing RNA interference Initiation of translation
1. the 3 end can be cleaved to produce different transcript lengths before addition of the poly-a-tail. 2. acetylation of histones facilitates transcription. 3. The RISC degrades mRNA complexed with miRNA or siRNA. 4. Transcriptional repressors compete with activators for DNA binding sites. 5. RNA granules control the availability of mRNA for translation. 6. Gene inversion does not cause a loss of genetic information but may affect regulation of the inverted genes.
68. Which of the following factors determine cell fate?
cytoplasmic determinants
genome sequence
signals from neighboring cells
cell location in the embryo
Each eukaryotes can regulate gene expression. Determine which of the five mechanisms each example represents. Not all examples will be used.
changes in chromatin structure Activity of transcription apparatus RNA processing RNA interference Initiation of translation
1. the 3 end can be cleaved to produce different transcript lengths before addition of the poly-a-tail. 2. acetylation of histones facilitates transcription. 3. The RISC degrades mRNA complexed with miRNA or siRNA. 4. Transcriptional repressors compete with activators for DNA binding sites. 5. RNA granules control the availability of mRNA for translation. 6. Gene inversion does not cause a loss of genetic information but may affect regulation of the inverted genes.
68. Which of the following factors determine cell fate?
cytoplasmic determinants
genome sequence
signals from neighboring cells
cell location in the embryo
Cell Biology
62.
A homeotic gene is a gene that
is responsible for maintaining cellular conditions.
is expressed only in a specific tissue type after development.
assigns tissue identity during development.
is expressed at similar levels in all tissues.
is expressed during development.
63.
All of the cells in the human body contain the same genes. How do cells have different morphologies and functions when they contain the same genetic information?
Different cell types express particular genes at different levels.
Different cell types receive different endocrine signals.
Different cell types obtain different types of nutrients from their surroundings.
Different cell types synthesize proteins at a different rate.
A homeotic gene is a gene that
is responsible for maintaining cellular conditions.
is expressed only in a specific tissue type after development.
assigns tissue identity during development.
is expressed at similar levels in all tissues.
is expressed during development.
63.
All of the cells in the human body contain the same genes. How do cells have different morphologies and functions when they contain the same genetic information?
Different cell types express particular genes at different levels.
Different cell types receive different endocrine signals.
Different cell types obtain different types of nutrients from their surroundings.
Different cell types synthesize proteins at a different rate.
Cell Biology
59. Arrange the following steps of the regulation of the trp operon in order of occurrence.
1. Rna polymerase binds to the promoter, allowing transcription of the trp genes to proceed. 2. Enzymes produced from the trp genes catalyze tryptophan production 3. sufficient quantities of tryptophan make further synthesis unnecessary. 4. Tryptophan activates the trp repressor protein. 5. the trp repressor protein binds to the operator. 6. the trp repressor protein blocks RNA polymerase from binding to the promoter.
60.
An operon is a group of genes under the control of a single promoter. Match each type of operon with the descriptions below.
Inducible repressible constitutive
A. under default conditions, transcription is inhibited. b. activating the repressor gene product inhibits transcription. c. the amount of gene product is constant d. Sufficient amounts of the gene product inhibit further transcription
1. Rna polymerase binds to the promoter, allowing transcription of the trp genes to proceed. 2. Enzymes produced from the trp genes catalyze tryptophan production 3. sufficient quantities of tryptophan make further synthesis unnecessary. 4. Tryptophan activates the trp repressor protein. 5. the trp repressor protein binds to the operator. 6. the trp repressor protein blocks RNA polymerase from binding to the promoter.
60.
An operon is a group of genes under the control of a single promoter. Match each type of operon with the descriptions below.
Inducible repressible constitutive
A. under default conditions, transcription is inhibited. b. activating the repressor gene product inhibits transcription. c. the amount of gene product is constant d. Sufficient amounts of the gene product inhibit further transcription
Cell Biology
51.
Which of the following are mechanisms by which cells communicate with each other? Check all that apply. More than one
cell junction
translation
pancrine signaling
cell cell recognition
56.
Classify the following statements as describing a protein kinase or a protein phosphatase.
protein kinase protein phosphatase
1. binds adenosine triphosphate 2. transfers a phosphate group to a protein. 3. dephosphorylates a protein 4. releases inorganic phosphate
Which of the following are mechanisms by which cells communicate with each other? Check all that apply. More than one
cell junction
translation
pancrine signaling
cell cell recognition
56.
Classify the following statements as describing a protein kinase or a protein phosphatase.
protein kinase protein phosphatase
1. binds adenosine triphosphate 2. transfers a phosphate group to a protein. 3. dephosphorylates a protein 4. releases inorganic phosphate
