Signal Transduction
What is the extracellular signal that initiates a signal transduction pathway?
Ligand or hormone
What type of feedback involves a response that increases the stimulus and moves a condition further from the set point?
Positive feedback
What are the three parts of interphase?
G1, S, G2
What kind of cells exhibit excessive mitosis?
Cancer cells
What are three types of molecules that can be found in an intracellular signal cascade?
Relay proteins, enzymes, second messengers
What type of feedback involves a response that removes a stimulus and brings a condition back to the set point?
Negative feedback
During mitosis, a parent cell divides to make two new cells. How do these cells compare to each other and to the parent cell?
Genetically identical
What will happen if a receptor's shape changes so that it does not fit the shape of its ligand?
The ligand won't bind, and signal transduction won't occur
What is the purpose of reception in a signal transduction pathway?
A ligand binds a receptor to initiate the pathway
The gas ethylene is a chemical signal that causes fruit to ripen and release more ethylene. What type of feedback is this?
Positive
What cellular response should occur if cells are injured and need to be replaced?
Mitosis
What intracellular signal molecule binds CDK to trigger mitosis?
Cyclin
What is the purpose of transduction (signal cascade) in a signal transduction pathway?
Transduction involves intracellular signals that transmit a message from the membrane to the nucleus
The hormone ADH is released when an individual is dehydrated (high blood osmolarity). ADH targets the kidneys. How will the kidneys respond to ADH in order to maintain homeostasis?
The kidneys will retain water in the blood rather than releasing water in the urine.
A plant cell goes through mitosis, but no cell plate forms. What is the result?
One cell with two nuclei
What extracellular signal (ligand) binds to a receptor to initiate a signal pathway that results in mitosis?
Growth factor
What cellular response occurs in the nucleus at the end of a signal transduction pathway?
Gene expression (DNA transcribed to mRNA translated to protein) is either stimulated or stopped
During blood clotting, a damaged blood vessel causes release of chemical that attract platelets which attract more chemicals that attract more platelets. What type of feedback is this?
Positive feedback
During mitosis, the spindle does not attach properly to chromosomes. What will be wrong with the two new cells?
The cells will not have equal numbers of chromosomes.
What will happen if a molecule blocks a growth factor from binding a receptor?
A signal pathway will not be initiated and mitosis will not occur.