Cell signaling Flashcards
module 4
What are the 4 essential elements of cellular communication?
1.) signaling cell
2.) signaling molecule
3.) receptor molecule
4.) receptor cell
Name the steps in cell signaling
1.) receptor activation
- signal binds to receptor, activating it
2.) signal transduction
- signal is transmitted to interior of cell by transduction
3.) response
- cell responds
4.) termination
- response is terminated so new signals can be received
What is the difference between communication in bacterial cells low and high density?
low density:
- concentration of signaling peptide is too low to bind to receptors and stimulate DNA uptake
high density:
- concentration of signaling peptide is high enough to bind to the receptors and stimulate DNA uptake
What do the endocrine, paracrine, autocrine and contact-dependent signaling have in common?
they are all possible cell signaling types in a multicellular body
Which types of multicellular cell signaling happens over long distances?
1.) endocrine signaling
Which types of multicellular cell signaling happens over short distances?
1.) paracrine signaling
2.) autocrine signaling
3.) contact-dependent signaling
Which signaling includes binding their signaling molecule to a close neighbouring cell receptor
paracrine signaling
Which signaling includes the signaling molecule travelling via circulatory system
endocrine signaling
Nancy K and Allan L identified the first
growth factor in paracrine signaling (platelet-derived growth factor: PDGF)
which signaling method includes the signaling cell and responding cell being the same cell
autocrine signaling
which signaling method includes a transmembrane protein on a the surface of one cell acting as the signaling molecule and a transmembrane protein on an adjacent cell acting as the receptor
contact-dependent signaling
T/F ligand is a signaling molecule
True
T/F polar signaling molecules can pass freely through the plasma membrane and activate cytoplasmic receptors
False: small non-polar signaling molecules can pass….
Difference between intracellular receptors and cell-surface receptors
intracellular:
- small, non-polar signaling molecules pass through the plasma membrane
cell-surface receptors:
- polar signaling molecules rely on cell-surface receptors as they cannot pass through the membrane
What does the animal endocrine system do
condensed response:
regulates an organisms response to the environment
in-depth response:
release chemical signals called hormones into the bloodstream that then respond to environmental cues, regulate growth and development and maintain homeostasis
T/F during molting growth, the organism goes through 5 molting instars before becoming a pupa
False: that is metamorphosis development; adult -> egg -> hatching -> 5 molting instars -> pupa -> metamorphosis (repeat)
T/F during molting growth, an organism goes through 5 nymphs after hatching
True
T/F the endocrine system is regarded as the “other” control system
True
How does the endocrine system work closely with the nervous system
the hypothalamus talks to the pituitary gland which then secretes many different hormones that affect other glands
T/F the parathyroids affect metabolism among other things
False: the thyroid gland affects metabolism + more.
the parathyroids help regulate calcium levels in the blood
T/F any organ that releases a hormone into the blood is part of the endocrine system
True
Describe the glucose negative feedback loop
1.) high/low blood glucose level [STIMULUS]
- high = directly after meal
- low = several hours after meal
2.) pancreas [SENSOR]
3.) insulin/glucagon [EFFECTOR]
- high = insulin
- low = glucagon
4.) body takes up glucose, muscles and lover take up glucose and store it as glycogen/muscle and liver break down down glycogen and release glucose [EFFECTOR]
- high = body takes up glucose, muscles and lover take up glucose and store it as glycogen
- low = muscle and liver break down down glycogen and release glucose
5.) decrease/increase in blood glucose [RESPONSE]
T/F a positive feedback loop can only be interrupted or broken by an external signal
True
What are the three major classes of hormones
1.) steroid hormones
2.) amine hormones
3.) peptide hormones
T/F steroid hormones are hydrophilic
False: they are hydrophobic, peptide and amine hormones are hydrophilic
T/F all steroid hormones are derived from cholesterol
True
T/F steroid hormones are the most abundant hormone
False: peptide hormones are the most abundant
T/F peptide hormones and amine hormones both derived from amino acids
True
This hormone is derived from a single aromatic amino acid
amine hormone
this hormone is a short chain of amino acids
peptide hormones
T/F hormones can only influence those cell types that express the receptor for that hormone
True
What hormones rely on cell-surface receptors
peptide and amine hormones (because they are hydrophilic, they cannot pass through the membrane).
they bind to cell-surface receptors that then activate a second messenger pathway which can change the metabolic state or gene expression of the target cell
What hormones rely on intracellular receptors
steroid hormones
they are hydrophobic meaning they can diffuse through the membrane where they can then bind to a cytoplasmic or nuclear receptor that then lets them act as transcription factor to alter gene expression of the cell
T/F hormones are typically released in large amounts
False: small
T/F Hormonal signaling pathways between endocrine glands and tissues are referred to as endocrine axes
True
T/F at each step, the hormonal signal can be amplified.
true
T/F the vertebrate endocrine system is localized in one part of the body
False: it is present all throughout; some targets have exclusively endocrine functions but many other tissues/organs keep endocrine cells that secrete hormones
T/F the anterior pituitary gland releases oxytocin and ADH
False: the posterior does
T/F the anterior pituitary gland communicates to the adrenal gland
True
Main difference between anterior and posterior pituitary gland
anterior:
- has endocrine cells
- hypothalamus releases hormones into bloodstream which causes the anterior to react, no direct contact.
- release hormones into bloodstream
posterior:
- no endocrine cells
- hypothalamus extends axon to it (direct contact) which signals when it needs to release hormones
- release hormones into bloodstream
T/F the posterior pituitary gland is part of the nervous system
True
Hormones that control the release of other hormones are called
tropic hormones
ex.)
AP - TSH - Thyroid gland = metabolic hormones
AP - FSH and LH - Ovaries
= estrogen and progesterone
