signal transduction and G protein-coupled receptors

Question 1

explain hydrophobic hormones

Answer 1

diffuse through the cell membrane and activate cytosolic receptors

Question 2

explain hydrophilic hormones

Answer 2

the bind to plasma membrane and activate signal transduction pathways

Question 3

some plasma membrane receptors activate ______ that trigger a variety of ______ or induce the generation of __________

Answer 3

G-protein switch proteins
downstream pathways
intracellular second messengers

Question 4

plasma membrane receptors that are tyrosine kinases trigger _____ involving sequential activation of downstream kinases

Answer 4

signal transduction

Question 5

signal transduction

Answer 5

the process of sensing external stimuli and conveying the information to intracellular targets

Question 6

hydrophobic signalling molecules

Answer 6

1. hydrophobic hormones diffuse through cell membrane
2. in the cytoplasm they bind a receptor/activator

Question 7

hydrophilic signalling molecules

Answer 7

1. binding leads to conformational change
2. activated receptor initiates downstream
3. signal transduction leads to the activation of effector proteins

Question 8

what target cells does endocrine affect?

Answer 8

taget cells some distance from site of synthesis

Question 9

what target cells does paracrine affect?

Answer 9

target cells in close proximity

Question 10

explain autocrine

Answer 10

cells respond to signals that they produce

Question 11

explain signal transduction by protein phosphorylation

Answer 11

proteins can be modified by multiple protein kinases or phosphates
kinase/phosphatase activity can be regulated by phosphorylation, by binding to other proteins, by binding of second messenger small molecules

Question 12

what are two types of kinases in animal cells

Answer 12

1. tyrosine (Y) kinases
2. serine (S) / threonine (T) kinases

Question 13

what does the human genome encode?

Answer 13

• 600 different protein kinases
• 200 different protein phosphotases