Basics of Communication

Question 1

List the three types of signalling between cells

Answer 1

Free diffusion between cells

Via cytoplasmic connections

By direct cell-to-cell contact

Question 2

True or False:

Free diffusion is the fastest way for a signal to be sent between cells

Answer 2

False

Cytoplasmic connections are the fastest way for a signal to be sent between cells

Question 3

True or false:

Cytoplasmic connections are the fastest way for a signal to be sent between cells

Answer 3

True

Question 4

What are the cytoplasmic connections between cells in animals?

Answer 4

Gap junctions

Question 5

What are the cytoplasmic connections between cells in plants?

Answer 5

Plasmodesmata

Question 6

Signalling and reception by free diffusion to and from the same cell is called what?

Answer 6

Autocrine diffusion

Question 7

Signalling and reception by free diffusion to and from nearby cells is called what?

Answer 7

Paracrine diffusion

Question 8

Signalling and reception by free diffusion to and from distant cells is called what?

Answer 8

Endocrine (hormones)

Question 9

What is the fastest form of free diffusion?

Answer 9

Autocrine

Question 10

What is the slowest form of free diffusion?

Answer 10

Endocrine

Question 11

What is autocrine diffusion important for?

Answer 11

Cell division, growth, regulation

Question 12

What is paracrine diffusion important for?

Answer 12

Nerves, embryonic development

Question 13

What is endocrine signalling important for?

Answer 13

Secreting hormones, homeostasis

Question 14

True or False:

Endocrine glands are ductless

Answer 14

True

Question 15

True or False:

Endocrine glands have ducts

Answer 15

False

Question 16

What signalling do muscle cells of the heart use to contract almost simultaneously?

Answer 16

Muscle cells in the heart communicate by cytoplasmic connections (fastest mode of cell-cell communication)
Via gap junctions

Question 17

How can cells recognise other cells in animals?

Answer 17

Via cell to cell contact, interactions between their surface molecules and receptors.

Question 18

What is cell-to-cell contact important for in the body?

Answer 18

Embryonic development and immune response

Question 19

What is signalling by cell-to-cell contact?

Answer 19

Specific interactions between surface molecules on one cell and receptors on another cell

Question 20

True or False:

Growth factors are local regulators

Answer 20

True

Question 21

What are growth factors?

Answer 21

Peptides or proteins that stimulate cell proliferation

Can have more than one target cell & might affect different cell types differently

Question 22

Give an example of a growth factor

Answer 22

Nerve Growth Factor (NGF) - small protein that regulates growth of target neurones

Question 23

True or False:

Gases can be local regulators

Answer 23

True

Nitric oxide acts as a paracrine signal molecule

Question 24

What is nitric oxide synthesised from?

Answer 24

Amino acid arginine by nitric oxide synthase

Question 25

What does the paracrine signal molecule nitric oxide do?

Answer 25

Induces vasodilation in cardiovascular system

Used in viagra to help with erectile dysfunction

Question 26

True or False:

Prostaglandins are modified fatty acids

Answer 26

True

Question 27

True or False:

Prostaglandins are local regulators

Answer 27

True

Question 28

What are the functions of prostaglandins?

Answer 28

Causes contractions of uterine wall during childbirth to get stronger (secreted by placenta, induces labour) (POSITIVE FEEDBACK LOOP)

Induces fever in the body and inflammation in local area of infection

Question 29

True or false:

Aspirin and ibuprofen inhibit prostaglandin synthesis

Answer 29

True

Prostaglandins induce fever in the body and inflammation in local area of infection. Inhibition of this alleviates pain.

Question 30

True or false:

Neurotransmitters are local regulators

Answer 30

True

Question 31

List four neurotransmitters

Answer 31

Acetylcholine

Biogenic amines (eg; serotonin)

Amino acids (eg; Glutamate)

Neuropeptides (eg; endorphines)

Question 32

True or False:

All neurotransmitters are always either inhibitory or excitatory

Answer 32

False

Some neurotransmitters can be either inhibitory or excitatory depending on their target