Chapter 9 Flashcards
What is an activated carrier?
cofactor, non protein chemical compound that is bound to a protein and required for the protein’s biological activity
- commonly enzymes and cofactors -> considered “helper molecules” that assist in biochemical transformations
How do cells communicate with each other? What are 4 categories of signaling as defined in the first few pages of chapter 9? What are examples of each?
Cell receptors detect external signals
-may involve direct contact with another cell or detection of a signal molecule
- ) Endocrine Signaling - long distance (testosterone, insulin)
- ) Paracrine Signaling - short distance ( signal traveling up and down spinal cord of developing embryo)
- ) Synaptic Signaling - signal travels across a synapse ( nervous system signaling)
- ) Direct Contact - cells must be in contact with each other, often binded by receptor
Why is phosphorylation useful in intracellular signaling cascades? Give 3 examples from your textbook.
Phosphorylation acts as an on/off switch for protein enzymes - causes a conformational change -> alters substrate
Growth factor (see fig 9.10)
Insulin receptor and glycogen synthesis (see fig 9.7 and 9.8)
RTK’s and MAPK pathway
Define: kinase, phosphatase
Kinase - adds phosphates (phosphorylate) -> enzyme that catalyzes transfer of a phosphate group from ATP to a specified molecule
Phosphatase - removes phosphates (de-phosphorylate) -> enzyme that catalyzes hydrolysis of organic phosphates in a specific (acidic or alkaline) reactions
Why are intracellular signaling cascades such as the MAP kinase pathway necessary?
amplify intracellular messages –> leads to cellular responses, produce multiple intracellular signals for every one receptor that is bound
Describe how the binding of a molecule of insulin to a cellular receptor leads to the conversion of glucose to glycogen
When insulin binds to insulin receptor, the receptor is phosphorylated –> another molecule can bind within that receptor after its phosphorylated –> new enzyme binds to molecule glucose synthase –> glucose is then synthesized and converted to glycogen inside the cells
Look up an additional example of an intracellular signaling cascade in your textbook. Describe the signal, the intracellular signaling pathway, and the cellular response that occurs as a result.
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