4.1
What are the three general ways cells can communicate through?
1. Direct contact
2. Local signaling
3. Long distance
What are the three stages of cell-to-cell messaging?
1. Reception
2. Transduction
3. Response
Signal transduction pathways influence how the cell responds to its environment?
True or false?
True
The internal and external cell environments never change.
True or false?
false
Which phase is the longest in the cell cycle?
Interphase
How do animal cells communicate in direct contact?
through gap junction
How does the receptor activates?
via a conformational change
What characteristic is necessary for survival?
The ability to respond to a stimuli
What is the definition of homeostasis?
the maintenance of a stable internal environment.
How many phases are in mitosis, and what are they?
There are 5 stages in mitosis, they are known as:
Prophase
Prometaphase
Metaphase
Anaphase
Telophase and cytokinesis
What are two examples of local regulators?
Synaptic signaling
Paracrine signaling
Where are the receptors located?
Receptors can be in the plasma membrane or intracellular.
What can signaling pathways target?
Signaling pathways can target gene expressions.
What happens if a system is disrupted?
Negative feedback mechanisms return the system back to its target set point.
How many times do normal cells divide?
Divide on average 20-50 times in culture (in petri dishes)
What do neurons secrete during synaptic signaling?
neurotransmitters
How does the signal transduction pathway regulate protein activity?
Phosphorylation by the enzyme protein kinase
What can be a response of signal transduction?
Apoptosis
What occurs when the stimulus is further activated?
Amplification
What does the uncontrollable growth of cancer cells lead to?
Tumors
Explain endocrine signaling
Specialized cells release hormones into the circulatory system where they reach target cells.
Give an example of cellular response:
A. Protein that can alter membrane permeability
B. Enzyme that will change a metabolic process
C. Protein that turns genes on or off
What do changes in protein type and/or amount result in?
a phenotype change
Give an example of a positive feedback
Childbirth
Lactation
Ovulation
Blood clotting
fruit ripening
In eukaryotes, DNA is packaged around proteins. What proteins are these?
histones