#Question id: 1106
#Unit 4. Cell Communication and Cell Signaling
Protein kinase is an enzyme that functions in which of the following ways?
#Question id: 3753
#Unit 3. Fundamental Processes
Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
#Question id: 32248
#Unit 2. Cellular Organization
#Question id: 2219
#Unit 2. Cellular Organization
Cholesterol and phospholipids are transported between organelles by
i. Golgi-dependent mechanisms.
ii. incompletely characterized vesicle populations.
iii. direct contact between membranes and, to some extent, small, soluble lipid-transfer proteins.
Which of the following statements are correct?
#Question id: 2986
#Unit 2. Cellular Organization
During ubiquitin-mediated protein degradation in various events of cell cycle, ubiquitin-protein ligases ubiquitinylate substrate proteins, marking them for degradation by proteasomes. Cyclins are degraded through the action of two different ubiquitin-protein ligases, SCF and the anaphase-promoting complex or cyclosome. Following statements are regarding to SCF and APC/C.
A. SCF controls the G1–S phase transition by degrading G1/S phase cyclins and, CDK inhibitory proteins.
B. APC/C degrades S phase and mitotic cyclins, thereby promoting the exit from mitosis.
C. SCF and APC/C are multi-subunit ubiquitin-protein ligases that belong to the RING finger family of ubiquitin protein ligases.
D. SCF and APC/C belong to the different ubiquitin-protein ligase family, their regulation is same.
E. SCF recognizes its substrates only when they are phosphorylated.
F. SCF and APC/C both recognizes its substrates only when they are phosphorylated.
Which of the following is incorrect?