What occurs in the G2 phase of interphase?
A. The cell duplicates its DN
B. The cell checks DNA and prepares for mitosis.
C. The cell performs its normal function.
D. The cell breaks down the nuclear envelope and coil chromatin.
查看答案
The enzymes that attach phosphate to proteins and play a major role in regulation in cell cycle are called
A. DNA polymerase.
B. growth factors.
C. proteases.
D. protein kinases.
Cells in a multicellular organism also usually communicate by chemical messengers. They can communicate by direct contact through cell junctions that connect the cytoplasm of adjacent cells. What is the cell junction found in animal cells referred to as?
A. plasmodestmata
B. cytosol junctions
C. gap junctions
D. short distance junctions
There are differed signaling mechanisms found in cells. Which of the following are correctly paired?
A. gap junction - intravenous communication
B. endocrine - substrate communication
C. synaptic - neural communication
D. receptor - communication using hormones
In animal cells that lack the ability to produce GTP, what is the correct result for this signaling system?
A. It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
B. It could activate only the epinephrine system.
C. It would be able to carry out reception and transduction but would not be able to respond to a signal.
D. It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
微信支付 
支付宝支付