Mod 9 Cell Signalling

Question 1

What does cell signalling do?

Answer 1

transfer info from outside to inside

communicate to receive or send chemical signals, can take place in short or long distances

Question 2

what are the four elements of cell communication?

Answer 2

signalling cell, signalling molecule, receptor molecule, receptor cell

Question 3

in prokaryotic cells, signalling in bacteria, what happens if there is low density of bacteria?

Answer 3

low peptide levels meaning no gene transfer

Question 4

in prokaryotic cells, signalling in bacteria, what happens if there is high density of bacteria?

Answer 4

high peptide levels, and all bacteria in same space exchange genetic info, respond synchronously

Question 5

in eukaryotic cells, what is receptor activation responsible for?

Answer 5

binding signalling molecules

Question 6

in eukaryotic cells what is signal transduction responsible for?

Answer 6

transmission of signal into the cell

Question 7

in eukaryotic cells, what is cellular response responsible for?

Answer 7

specific in targeting cell

Question 8

in eukaryotic cells what is signal termination responsible for?

Answer 8

the stop response

Question 9

what is a signal attaching to receptor called?

Answer 9

ligands

Question 10

what happens when there is no receptor?

Answer 10

no response

Question 11

what are the changes that occur in receptor when ligand binds to ligand-binding site?

Answer 11

conformational change in receptor triggering chemical reactions within cytosol

Question 12

what happens when a ligand is hydrophobic and nonpolar?

Answer 12

can easily pass through

Question 13

what happens if ligand is hydrophilic and polar?

Answer 13

not going to cross membrane and only attach to receptors on the surface

Question 14

what happens when receptor is activated and transmits message to cell through cytoplasm?

Answer 14

signal transduction

Question 15

where does the message go from signal transduction?

Answer 15

cytosol or go to nucleus

Question 16

what happens when distinct proteins are activated in particular sequence?

Answer 16

often amplified

Question 17

what happens when cell is amplified?

Answer 17

only one signal impact response that is big and quick (heart rate)

Question 18

what happens when a signal has been received, acted upon, and terminated?

Answer 18

stops the cellular response

Question 19

what are the four types of cell signalling?

Answer 19

endocrine signalling, paracrine signalling, autocrine signalling, contact-dependent signalling

Question 20

what are the short distance signalling types?

Answer 20

paracrine signalling, autocrine signalling, and contact-dependent signalling

Question 21

what is the signalling type that signals to itself?

Answer 21

autocrine signalling

Question 22

what is the signalling type that signals to neighbouring cells?

Answer 22

paracrine signalling

Question 23

what do endrocrine signalling cells signal to?

Answer 23

long distance travel through bloodstream, use chemical signalling molecules - hormones

Question 24

which cell signalling type is particularly important for embryonic developement?

Answer 24

autocrine signalling

Question 25

which cell signalling types are important for growth factors?

Answer 25

endocrine signalling, paracrine signalling

Question 26

which cell signalling type can travel within range of - 20 cells?

Answer 26

paracrine signalling

Question 27

which cell signalling is also called juxtacrine signalling?

Answer 27

contact-dependent signalling

Question 28

what type of molecules can attach to intracellular receptors?

Answer 28

nonpolar, hydrophobic molecules

Question 29

where are intracellular receptors located?

Answer 29

in cytosol floating around or nucleus

Question 30

what are the different types of proteins that are involved in cell signalling?

Answer 30

g-protein-coupled receptor -gpcr, receptor kinases, ion channels

Question 31

what units are GPCRs composed of?

Answer 31

alpha, beta, gamma

Question 32

do GPCRs associate with G protiens?

Answer 32

yes, bind to GTP and GDP in the cytoplasm

Question 33

what is GPCR when bound to GTP?

Answer 33

active

Question 34

what is GPCR when bound to GDP?

Answer 34

inactive

Question 35

what is the main steps of GPCR activation?

Answer 35

ligand bind, receptor changes, attach to alpha subunit, attach to target protein

Question 36

in signal amplification, which three areas are affected?

Answer 36

activation of multiple G proteins, produce large amounts of cAMP, activation of multiple protein targets

Question 37

what is it called: the time a ligand is bound to receptor depends on how tightly receptor hold on to it

Answer 37

binding affinity

Question 38

what happens to GPCR when g protein converts GTP to GDP

Answer 38

become inactive

Question 39

what happens when adenylyl cyclase is inactivated?

Answer 39

no more cAMP is formed

Question 40

what happens when cAMP is degraded by enzymes in the cytosol?

Answer 40

stops activation of more protein kinase A molecules

Question 41

what happens when phosphatases remove phosphate groups from activated proteins?

Answer 41

inactivates proteins

Question 42

what do phosphatases do?

Answer 42

enzyme that dephosphorylate target proteins

Question 43

when do receptor kinase become active?

Answer 43

when ligand binds

Question 44

what is it called? when receptors that turn into dimers?

Answer 44

dimerization

Question 45

what are the main steps of receptor kinase activation and signalling?

Answer 45

ligand binds to receptor, dimerization occur, use ATP to help each member of receptor pair to attach to phosphate group, phosphate groups allow binding sites for intracellular signalling proteins

Question 46

what are some examples of receptor kinase signalling?

Answer 46

wound healing

Question 47

what are the three different types of ion channels that can be gated?

Answer 47

ligand-gated, voltage-gated, mechanically-gated

Question 48

what prevents movement of the ion in ligand-gated ion channels?

Answer 48

gate is closed

Question 49

what allows movement of the ion in ligand-gated ion channels?

Answer 49

gate is open