cell communication

Question 1

purpose of communication

Answer 1

• growth and division control
• regulate development of cells to tissues
• coordinate metabolic activities

Question 2

direct cell communication types

Answer 2

• gap junctions = cell junctions between cytoplasm by jooining membranes
• cell surface molecule interaction = receptors on a cell physically attach to surface proteins of another

Question 3

local communication types

Answer 3

1. autocrine - hromomne binds to same cell, recpetors on same cell or cytoplasm recieves
2. paracrine - release hormones for nearby cells (includes neurotransmission)
3. endocrine - distant, blood flow

Question 4

what is a hormone and characteristics

Answer 4

molecule produced in one tissue and causes change in another
- secreted into body fluids
- bind to receptors (specific)
- initiate changes

Question 5

what are receptors

Answer 5

• proteins that binds to ligand (homeormes etc)
• can be on cell wall or nucleus

Question 6

types of receptors

Answer 6

• transmembrane = span cell mebrane with ntracellular and extracellular parts - recpetor on extra, cause intra effect
• intracellular = recpetors in cytoplasm, typically lgland activated transcription factors whcih change shape and interact with DNA to transcribe

Question 7

types of transmembrane receptors

Answer 7

• enzyme linked = enzyme activated by binding of ligland
• ion channel-linked = binding of ligland opens or closes a channel
• g protein coupled receptors = membrane bound receptor is coupled to a guanine nucleotide binding protein

Question 8

what are nerve cells

Answer 8

• excitable cells that respond to external stimuli through a rapid and reversible alterantion to electrical potential of cell mebrane

Question 9

how is external stimuli interpreted

Answer 9

• converted to electrical signals
• transmitted from peripheral to central
• generates electrical signal trasmitted to effector cells via peripheral nerves

Question 10

how does a nerve impulse work

Answer 10

• local depolarisation causes permeability
• acto=ion potential moves down axon
• once at end of neuron, propagation of an impulse by electrical currents between active and inactive area of nerve

Question 11

how are nerve impulses passed

Answer 11

• acetylcholine released from synaptic vessel and diffuses across synaptic gap
• bnds to specific recpetor on post-synaptic membrane

Question 12

neurotransmission in muscle contraction

Answer 12

• acetylcholchine binds to muscle cell receptor and causes depolarization.
• cause release of Ca2+ in muscle cell
• myosin interacts with actin = contracts

Question 13

how is muscular ATp generated

Answer 13

1. creatine phosphate
2. catbolism (lactic acid fementation)

Question 14

modes of molecule transport across a membrane

Answer 14

• passive diffusion
• import/export via receptors
• nuclear transport
• microtubule
• anterograde transport (ER to golgi)
• retrograde (golgi to ER)

Question 15

how do prokaryotes move

Answer 15

• flagella coposed of filament, hook and basal body
• requires ATP to move it
• cilia - extension of plasma membrane

Question 16

flagella vs cilia

Answer 16

cilia = small
many cells
cell stationary - move fluids around it instead

flagella =
long
one cell
entire cell movements