Signalling Molecules (6.1) Flashcards
State the 2 types of environments from which multicellular organisms can detect and respond to signals
- internal
- external
Describe response
Action or change in functionality of a cell that occurs as a result of a specific stimulus
Describe stimulus
Chemical or physical change that activates a receptor molecule in a cell and generates a response
Describe stimulus-response model
Explanation of the mechanism by which an organism, organ or cell changes its behavior or physiology as a consequence of changes in its internal or external environment
State 5 different types of stimuli
- Variations in nature
- Changes in pressure
- Light
- Temperature
- Chemical molecules
Describe signalling molecules
A molecule involved in chemical communication between cells
State whether or not all cells can detect stimuli
Not all cells are capable of detecting stimuli
State whether or not all cells can respond to stimuli
Not all cells can respond to stimuli
State where cells that are capable of detecting stimuli can pass detected information to
Other cells
State how cells that are capable of detecting stimuli can pass detected information to other cells
Signalling molecules
State what cells respond to signalling molecules
Effector cells
Describe effector cells
A cell that responds to signalling molecules
State whether or not signalling molecules can trigger a response even at very low concentrations
Yes. Signalling molecules are able to trigger a response at very low concentrations
State the 2 different environments communication via signalling molecules can occur
- nearby environments
2. distant environments
State what signalling is a mode of
Mode of transmission
Describe autocrine signalling
Signalling molecules act on the actual/same type of cell that secreted them
Describe paracrine signalling
Signalling molecules act on cells that are close to the secreting cell
Describe endocrine signalling
Signalling molecules act on cells that are far from the cell that secretes them
State the 3 modes of transmission of signalling molecules
- autocrine
- paracrine
- endocrine
State what signalling molecules can be classified as
- hydrophobic
2. hydrophilic
State the 5 groups of signalling molecules
- animal hormones
- plant hormones
- neurotransmitters
- cytokines
- pheromones
Describe hormones
Signalling molecule produced in tiny amounts that can have relatively long lasting effects on target cells
State what hormones help to regulate
Growth and activity of cells in most plants and animals
Describe the endocrine system
The animal body system that is responsible for the production of hormones
State what the endocrine system is responsible for coordinating in vertebrates
Bodily functions
State what the endocrine system is made up of
Many glands and organs within the body
State what the endocrine system is made up of
Many glands and organs within the body
What does the endocrine system utilise for the transport of synthesised hormones?
Bloodstream
State the 3 major classes of animal hormones
- Lipid hormones
- Peptide and protein hormones
- Amino-acid derived hormones
Outline the source of animal hormones
Glands and organs
Outline the source of plant hormones
Most plant cells
Outline the source of neutrotransmitters
Neurons
Outline the source of cytokines
Many cells (including immune system cells)
Outline the source of phermones
Various cells (dependent on species)
State the modes of transmission of animal hormones
- autocrine
- paracrine
- endocrine
State the modes of transmission of plant hormones
- various (including diffusion)
State the modes of transmission of neutrotransmitters
- paracrine
State the modes of transmission of cytokines
- autocrine
- paracrine
- endocrine
State the modes of transmission of pheromones
- diffusion in the external environment
Provide more detail of the transmission of animal hormones through the paracrine mode
Signal carried through interstitial fluid between cells
Provide more detail of the transmission of animal hormones through the endocrine mode
Signal carried through blood circulation
Provide more detail of the transmission of neutrotransmitters through the paracrine mode
Signal carried through exocytosis into the synaptic gap and diffusion across the gap
State what group of signalling molecules steroid hormones belong to
Animal hormones
State what group of signalling molecules peptide hormones belong to
Animal hormones
State what group of signalling molecules animal acid derived hormones belong to
Animal hormones
State the 5 major classes of plant hormones
- abscisic acid
- auxins
- cytokinins
- ethene
- gibberellins
State what group of signalling molecules abscisic acid hormones belong to
Plant hormones
State what group of signalling molecules auxins belong to
Plant hormones
State what group of signalling molecules cytokinins belong to
Plant hormones
State what group of signalling molecules ethene belongs to
Plant hormones
State what group of signalling molecules gibberellins belong to
Plant hormones
State whether steroid hormones are hydrophobic or hydrophilic
Hydrophobic
State whether peptide hormones are hydrophobic or hydrophilic
Hydrophilic
State whether amino acid derived hormones are hydrophobic or hydrophilic
Hydrophobic or hydrophilic
State whether phytohormones are hydrophobic or hydrophilic
Hydrophobic or hydrophilic
State whether pheromones are hydrophobic or hydrophilic
Hydrophobic or hydrophilic
State what lipid hormones are derived from
- fatty acids
- cholesterol
Provide 1 example of a lipid hormone
Cortisol
Provide 1 example of a peptide hormone
Insulin
Provide 1 example of a protein hormone
Growth hormone
Provide 1 example of an amino-acid derived hormone
Adrenaline
State the 2 classifications of amino-acid derived hormones
- catecholamines
2. thyroid hormones
State whether catecholamines are hydrophobic or hydrophilic
Hydrophilic
State whether thyroid hormones are hydrophobic or hydrophilic
Hydrophobic
State whether or not a single hormone can trigger different responses in multiple target cells at the same time
Yes. A single hormone can trigger different responses in multiple target cells at the same time.
State what plant hormones can be referred to as
Phytohormones
State the visible effects of abscisic acid hormone
Seed and bud dormancy
State the visible effects of auxins
- phototropism
- gravitropism
Describe phototropism
Shoot tips bend towards the light
Describe gravitropism
Roots grow downwards
State the visible effects of cytokinins
Growth of lateral branches
State the visible effects of ethene
- fruit sugar content
- fruit and leaf drop
State the visible effects of gibberellins
- stem elongation
- leaf expansion
- seed germination
- fruit and flower maturation
Describe neutrotransmitters
Group of signalling molecules produced by neurons and used to carry a signal across synapses between cells
State what cellular responses neutrotransmitters are involved in
- regular hormone production
- organ function
- movement
Describe synapses
Point of communication between two cells where at least one of the cells is a neuron
Describe the postsynaptic neuron
A neuron to which an electrical impulse is transmitted across a synaptic cleft by the release of neurotransmitters from the axon terminal of a presynaptic neuron
State 3 possible sources of cytokines
- macrophages
- T lymphocytes
- B lymphocytes
State what pheromones influence
The behaviour and physiology of another individual (usually of the same species)
State why multicellular organisms produce signalling molecules
Form of intracellular communication
Describe cytokines
One of a group of peptides and proteins released for signalling between cells of the immune system
Describe pheromones
Group of signalling molecules that are excreted from the body and diffuse through the air to elicit a response from another individual
State what pheromones influence
The behaviour and physiology of another individual (usually of the same species)
State why multicellular organisms produce signalling molecules
Form of intracellular communication
Describe abscisic acid
A plant hormone involved in many plant develoment processes
Describe auxins
A plant hormone that stimulates growth.
Describe cytokinins
A plant growth hormone that promotes cell division/cytokinesis in plant roots and shoots
Describe ethene
A gaseous plant hormone involved in promoting fruit ripening
Describe gibberellins
A class of plant hormones that promotes stem elongation and germination
Describe abscission
The natural detachment of parts of a plant, typically dead leaves and ripe fruit.
State whether or not any molecule that causes a response by a cell is considered a signalling molecule
Yes.
