Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOSCI 107 Part One > Cell Structure and Function: Cell Signalling > Flashcards

Cell Structure and Function: Cell Signalling Flashcards

1
Q

What is local signalling?

A

Signals that act on nearby targets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is paracrine signalling

A

Is when a cell produces a signal to induce change in nearby cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an example of paracrine signalling?

A

Growth factors such as fibroblasts growth factor (FGF1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is synaptic signalling?

A

similar to paracrine signalling but have junctions (synapses) between the cell produces the signal ( neurotransmitters) and the cell receiving the signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is an example of synaptic signalling?

A

Acetylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is long distance signalling?

A

are signals that act from a distance. Hormones produced by specialised cells travel via circulatory system to act on specific cells (produced from endocrine system)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some examples of long distance signalling?

A

insulin from pancreatic beta cells bind to insulin receptors (tyrosine kinase type) initiating a cascade which results in glucose uptake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the two types of local signalling?

A

Paracrine and Synaptic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the two types of secreted signals?

A

Local and long distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the three steps of cell signalling?

A

Reception, transduction, response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the first step of cell signalling?

A

Reception

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is reception?

A

Allows or causes the activation of a protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the two types of receptors?

A

Intracellular and membrane bound/cell surface receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are intracellular receptors?

A

Receptors inside our cells

They are the least common type of receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where are intracellular receptors located?

A

Cytoplasm or cytosol of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Examples of ligands that bind to intracellular receptors

A

Testosterone, estrogen, progesterone, thyroid hormones bind to receptors in the cytoplasm (they are hydrophobic so they can pass through plasma membrane) and move to nucleus as a complex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a ligand/primary messenger/signalling molecule?

A

a signalling molecule that binds to another (usually larger) specific protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How can some ligands cross the plasma membrane to reach intracellular receptors?

A

They are hydrophobic and/or small

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are membrane bound/cell surface receptors?

A

Receptors embedded in the plasma membrane of the cell/membrane of organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Function of membrane bound receptors?

A

To allow primary messengers that are hydrophilic and/or large to cross the plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Examples of membrane bound receptors

A

G Protein Coupled Receptor, Receptor Tyrosine Kinase, ligand-gated ion channel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are G-protein coupled receptors (GPCRs)?

A

A membrane bound receptor that is also a transmembrane protein that crosses the plasma membrane 7 times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are transmembrane domains?

A

The loops on a GPCR that are in the hydrophilic regions inside and outside a cell so they can interact with molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are G proteins

A

the proteins that GPCR’s are coupled with. They are molecular switches that are either on or off depending on whether GDP or GTP is bound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is GTP

A

An energy source, similar to ATP

26
Q

What is the process of GPCRs?

A

At rest, the receptor is unbound and G protein is bound to GDP (inactive). The enzyme is in an inactive state
Ligand binds to the receptor and binds the G protein and causes a conformational shape change of GPCR. GTP displaces GDP causing G protein to become activated. The enzyme is still inactive
Activated G protein dissociates from the receptor. Enzyme is activated and has a conformational shape change. It can elicit a cellular response
G protein has GTPase activity (release of GTP) promoting its release from enzyme reverting it back to resting state

27
Q

What are ligand gated ion channel/receptors?

A

A membrane bound receptor that contains a gate, which is closed until a ligand (e.g. a neurotransmitter) binds to it causing the gate to change shape and open

28
Q

What is a receptor?

A

a molecule/protein which responds to a specific ligand

29
Q

What is an ion channel?

A

membrane protein through which specific ions can travel

30
Q

What is an ion channel receptor?

A

membrane protein through which specific ions can

travel, in response to ligand binding (also known as ionotropic receptors)

31
Q

What is the process of ligand gated ion channels/receptors?

A

At rest ligand is unbound and the gate is closed
Upon ligand binding, the ligand gated ion channel receptor undergoes a shape change and the gate is opened and specific ions can flow into the cell (down concentration gradient)
Following ligand dissociation, the gate closes and goes back to resting

32
Q

What system relies heavily on ligand fated ion channels?

A

The nervous system. Released neurotransmitters binds, as ligands, to ion channels on target cells to propagate action potentials

33
Q

What is the second step of cell signalling?

A

Signal Transduction

34
Q

What is signal transduction?

A

Signals are relayed from receptors to target molecules within the cell via a ‘cascade’ of molecular interactions

35
Q

What is protein kinases

A

are enzymes that transfer a phosphate group from ATP to another protein. Typically, this activates the protein

36
Q

What are phosphatases?

A

are enzymes that dephosphorylate (remove the phosphate) rendering the protein inactive, but recyclable

37
Q

What does the last active protein kinases do?

A

activates an inactive protein which then carries out a cellular response

38
Q

What are the amino acids that are typically phosphorylated?

A

serine or threonine

39
Q

What is a secondary messenger?

A

A molecule that is generated when a specific substance attaches to a receptor on the outside of a cell membrane, which produces a change in cellular function.

40
Q

What is cAMP (cyclic AMP)?

A

A secondary messenger that is created when activated enzyme adenylyl cyclase converts ATP to cAMP. cAMP acts as a second messenger and activates downstream protein (which could be the start of a phosphorylation cascade)

41
Q

What disrupts the ATP to cAMP process

A

Cholera toxin

42
Q

What is calcium?

A

A secondary messenger released from the endoplasmic reticulum

43
Q

What is IP3?

A

A secondary messenger that diffuses through the cytoplasm and binds to a gated channel in the ER to release calcium ions

44
Q

Where is there a low [Ca2+] ?

A

Inside the cell

45
Q

Where is there a high [Ca2+]?

A

Outside the cell

46
Q

Where is Ca2+ pumped to maintain low calcium levels inside the cell?

A

Extracellular space, ER, Mitochondria

47
Q

What is PIP2

A

a specific phospholipid in calcium signalling

48
Q

What is Phospholipase C?

A

An enzyme that catalyses the splitting of PIP2 to IP3 and DAG.

49
Q

What is the process of IP3 and calcium acting as secondary messengers?

A

Here, the activated protein is phospholipase C which then cleaves PIP2 (a phospholipid) into DAG and IP3
IP3 (the secondary messenger) diffuses through cytosol and binds to a gated channel in the ER (as the ligand)
Calcium ions flow out of ER down concentration gradient (high to low) and activate other proteins towards a cellular response

50
Q

An example of a cellular response of calcium?

A

Muscles use Ca2+ to contract

51
Q

Why are there multiple steps on cell signalling between reception and cell response?

A

Amplifies the response
Provides multiple control points
Allows for specificity of response (temporal and spatial) despite molecules in common
Allows for coordination with other signalling pathways

52
Q

What does the transduction of a signal lead to?

A

The regulation of one or more cellular activities like gene expression

53
Q

Why is it important for cell signalling to be temporary/last a short period of time?

A

So that a cell can return to homeostatic equilibrium and be ready to respond again to another signal if required

54
Q

What is phosphodiesterase?

A

An enzyme that converts cAMP to AMP

55
Q

What blocks the action of phosphodiesterase?

A

Caffeine

56
Q

What does viagra inhibit?

A

The specific cGMP which degrades phosphodiesterase

57
Q

What is epinephrine?

A

Adrenalin

58
Q

What is the function of active glycogen phosphorylase?

A

Converting glycogen to glucose 1-phosphate

59
Q

How many glucose 1-phosphate molecules result from 1 adrenalin molecule?

A

108

60
Q

What is glycogen?

A

is a long term energy store in the liver and skeletal muscle

61
Q

What is glycogen breakdown?

A

Converting glycogen into glucose 1-phosphate

62
Q

What is glucose 1-phosphate converted into?

A

Glucose g-phosphate which can be used in glycolysis to generate ATP

BIOSCI 107 Part One (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions