Cell Signalling

Question 1

What is Saccharomyces Cerevisiae used in making?

Answer 1

Bread, beer and wine.

Question 2

How often does Saccharomyces Cerevisiae replicate?

Answer 2

Replicate every 90 mins.

Question 3

Would you say Saccharomyces Cerevisiae has a rapid cell cycle?

Answer 3

Yes

Question 4

When Saccharomyces Cerevisiae is anorobic, what is formed?

Answer 4

Alcohol

Question 5

Single celled organisms must be able to respond to?

Answer 5

Environmental changes or signals from other cells.

Question 6

The single cell organisms within our bodies respond to?

Answer 6

The food we consume

Question 7

Development of plants and animals require?

Answer 7

Complex communication and signalling

Question 8

When does yeast mate?

Answer 8

When there is limited nutrient availability.

Question 9

Saccharomyces Cerevisiae is?

Answer 9

Single cells yeast that divides by budding small daughter cells.

Question 10

Yeast exists in how many mating types?

Answer 10

2

Question 11

Yeast mate by?

Answer 11

Signalling to each other and reacting to each other’s receptors.

Question 12

The production of the diploid cell has how many chromosomes compared to its parents?

Answer 12

Double the number of each of the parent cells.

Question 13

Signalling between different yeast mating types involves what?

Answer 13

Signal transduction pathways

Question 14

Plasmodesmata are?

Answer 14

Analogous structures in plants.

Question 15

Cell-cell contact always allows?

Answer 15

Signalling.

Question 16

In animals, what do gap junctions allow?

Answer 16

Cytoplasmic contact.

Question 17

Adjacent cells in animals can interact through?

Answer 17

Surface Proteins.

Question 18

What process converts events at the cell surface into specific cellular responses?

Answer 18

Signal transduction pathways.

Question 19

In yeast mating, factors from each mating type bind to receptor proteins in the plasma membrane and this leads to?

Answer 19

Altered intercellular events. (Changes within the cell.)

Question 20

What type of signalling repairs damaged tissue?

Answer 20

Paracrine Signalling

Question 21

How does paracrine signalling repair damaged tissue?

Answer 21

Stimulates near by cells to replicate them.

Question 22

What are the two types of communication in animals?

Answer 22

Local and long distance.

Question 23

Synaptic signalling is exclusive to?

Answer 23

The nervous system.

Question 24

Synaptic signalling can be considered to be both?

Answer 24

Local and long distance.

Question 25

What happens during synaptic signalling?

Answer 25

One cell sends a signal across a structure called a synaptic junction and this will influence neighboring cells.

Question 26

Hormonal signalling is also known as?

Answer 26

Endocrine signalling.

Question 27

How does hormonal signalling work?

Answer 27

Cells release hormones into the circulation which can reach almost all cells of an organism but they only cause a response in cells that have appropriate protein receptors.

Question 28

What are the three mechanistic steps that explain enzyme activation/three stages of cell signalling?

Answer 28

Reception, Transduction and Response.

Question 29

How many signalling molecules will a cell in your body be responding to?

Answer 29

20.

Question 30

What type of molecules can pass straight through a cell membrane?

Answer 30

Hydrophobic.

Question 31

What happens in the first stage of cell signaling?

Answer 31

Reception: signalling molecule outside the cell is detected by the cell. Binding of signalling protein, normally on cell surface but occasionally inside cell. Binding alters the confirmation of the receptor which then activates the next stage of the pathway. (Energy Passes)

Question 32

What is the second stage of cell signalling?

Answer 32

Transduction.

Question 33

What happens in the transduction stage?

Answer 33

Receptor starts a series of steps leading to a cellular response.

Question 34

The final stage of cell signalling is called?

Answer 34

Response.

Question 35

What is the response triggered by?

Answer 35

The last component of the signal transduction pathway.

Question 36

Will the response be a measurable change?

Answer 36

Yes.

Question 37

What are receptors?

Answer 37

Proteins with particular affinity to signalling molecules.

Question 38

What features are common in signal transduction pathways?

Answer 38

Receptors, kinases and phosphates, second messengers, protein clustering.

Question 39

2% of all human genome is devoted to what?

Answer 39

Kinases and phosphates.

Question 40

What can make and active protein, inactive and vice versa?

Answer 40

Kinases and phosphates.

Question 41

Signals can only be responded to by cells that?

Answer 41

Contain specific receptor proteins.

Question 42

Signalling molecules only fit in specific receptors, sort of like a?

Answer 42

Key in a lock.

Question 43

What are the two types of receptor?

Answer 43

Plasma membrane receptors and intracellular/nuclear receptors.

Question 44

What does ligand-receptor binding cause?

Answer 44

A change in conformation of receptor activating a signal transduction pathway.

Question 45

What type of signalling molecule bind to plasma membranes?

Answer 45

Water-soluble.

Question 46

Intercellular domains change when?

Answer 46

Something links to the extracellular domain.

Question 47

Extracellular domains are linked to intercellular domains by?

Answer 47

Transmembrane spanning alpha-helices.

Question 48

What do G-Proteins act as?

Answer 48

Molecular Switches.

Question 49

What determines what the G-protein is set to?

Answer 49

Which guanine nucleotide is bound.

Question 50

What are the guanine nucleotides?

Answer 50

GDP and GTP.

Question 51

The protein is inactive when?

Answer 51

GDP is bound.

Question 52

What does activation require?

Answer 52

Exchange of GTP for GDP

Question 53

What do activated (GTP) G proteins bind to and modulate?

Answer 53

Effectors.

Question 54

How many membrane spanning alpha-helices do G protein coupled receptors have?

Answer 54

7.

Question 55

Activated G Proteins bind to? and what do they do to them?

Answer 55

Effector proteins and activate them.

Question 56

What happens to G proteins once effectors have been activated?

Answer 56

They rapidly inactivate.

Question 57

What percentage of prescribed drugs influence G proteins or their regulated pathways?

Answer 57

60%.

Question 58

Defective G proteins can cause cancers by?

Answer 58

Being locked into a constantly active state.

Question 59

What does RTK stand for?

Answer 59

Receptor tyrosine kinase.

Question 60

What are RTK's?

Answer 60

Receptors that have enzyme activity.

Question 61

In the activation of RTK's, what does dimerisation lead to?

Answer 61

Autophosphorylation and activation.

Question 62

What mechanism do lots of hormones work through?

Answer 62

Activation of RTK.

Question 63

Defective signalling through RTK pathways can cause?

Answer 63

Many human cancers.

Question 64

Mitogens that work on tissue repair work through what?

Answer 64

RTK's.

Question 65

How do ion channel receptors work?

Answer 65

Signalling molecules bind and this opens 'gates' which allow ions to flow down concentration gradients and this changes the cell behaviour.

Question 66

What are ion channel receptors used for?

Answer 66

Muscle contractions.

Question 67

What kind of receptors are found in the cytoplasm or nucleus?

Answer 67

Intracellular/Nuclear receptors.

Question 68

What type of molecules bind to intracellular/nuclear receptors?

Answer 68

Steroids, thyroid, hormones and nitric oxide.

Question 69

What happens when a receptor binds to specific DNA pattern?

Answer 69

Transcription patterns can be changed.

Question 70

What does a change in transcription patterns lead to?

Answer 70

Alteration of proteins within the cell.

Question 71

What is the ultimate purpose of a receptor?

Answer 71

To trigger a change within the cell.

Question 72

What is the advantage of a multi-step pathway?

Answer 72

It allows amplification and opportunities for fine-tuning.

Question 73

What do protein phosphorlases do?

Answer 73

Turn proteins on/off.

Question 74

Over 2% of all human genes code for?

Answer 74

Protein Kinases.

Question 75

What happens in phosphorylation cascades?

Answer 75

Receptor receives signal, it then changes shape and starts the process. Proteins phosphorylate each other and become active. This then leads to a response.

Question 76

Why are second messengers small and water soluble?

Answer 76

So they can diffuse rapidly through a cell.

Question 77

What are second messengers often the link between?

Answer 77

Activated receptors and signal transduction pathways.

Question 78

Examples of second messengers are?

Answer 78

cAMP, cGMP, IP3, DAG and CA2+.

Question 79

What does the c mean in cAMP and cGMP?

Answer 79

Cyclic.

Question 80

cAMP is increased by?

Answer 80

Activation of adenylyl cyclase.

Question 81

How does adrenaline work?

Answer 81

It binds to receptor, the receptor activates the G protein, this activates adenylyl cyclase which produces cAMP, cAMP-dependant protein kinase (PKA) is activated.

Question 82

When high cAMP stimulates secretion of salts and H20 into intestines, what may this cause?

Answer 82

Diarrhoea.

Question 83

What drug modulates second messenger concentrations?

Answer 83

Viagra.

Question 84

How does Viagra work?

Answer 84

Inhibits enzyme cGMP phosphodiesterase which breaks down cGMP. This leads to an increase in cGMP.

Question 85

Where can amplification occur?

Answer 85

Signal transduction pathways.

Question 86

What is cholera caused by?

Answer 86

A G protein being perpetually on.