Cell signaling

Question 1

What are the 4 essential elements of cellular communication?

Answer 1

1.) signaling cell
2.) signaling molecule
3.) receptor molecule
4.) receptor cell

Question 2

Name the steps in cell signaling

Answer 2

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

Question 3

What is the difference between communication in bacterial cells low and high density?

Answer 3

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

Question 4

What do the endocrine, paracrine, autocrine and contact-dependent signaling have in common?

Answer 4

they are all possible cell signaling types in a multicellular body

Question 5

Which types of multicellular cell signaling happens over long distances?

Answer 5

1.) endocrine signaling

Question 6

Which types of multicellular cell signaling happens over short distances?

Answer 6

1.) paracrine signaling
2.) autocrine signaling
3.) contact-dependent signaling

Question 7

Which signaling includes binding their signaling molecule to a close neighbouring cell receptor

Answer 7

paracrine signaling

Question 8

Which signaling includes the signaling molecule travelling via circulatory system

Answer 8

endocrine signaling

Question 9

Nancy K and Allan L identified the first

Answer 9

growth factor in paracrine signaling (platelet-derived growth factor: PDGF)

Question 10

which signaling method includes the signaling cell and responding cell being the same cell

Answer 10

autocrine signaling

Question 11

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

Answer 11

contact-dependent signaling

Question 12

T/F ligand is a signaling molecule

Answer 12

True

Question 13

T/F polar signaling molecules can pass freely through the plasma membrane and activate cytoplasmic receptors

Answer 13

False: small non-polar signaling molecules can pass….

Question 14

Difference between intracellular receptors and cell-surface receptors

Answer 14

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

Question 15

What does the animal endocrine system do

Answer 15

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

Question 16

T/F during molting growth, the organism goes through 5 molting instars before becoming a pupa

Answer 16

False: that is metamorphosis development; adult -> egg -> hatching -> 5 molting instars -> pupa -> metamorphosis (repeat)

Question 17

T/F during molting growth, an organism goes through 5 nymphs after hatching

Answer 17

True

Question 18

T/F the endocrine system is regarded as the “other” control system

Answer 18

True

Question 19

How does the endocrine system work closely with the nervous system

Answer 19

the hypothalamus talks to the pituitary gland which then secretes many different hormones that affect other glands

Question 20

T/F the parathyroids affect metabolism among other things

Answer 20

False: the thyroid gland affects metabolism + more.
the parathyroids help regulate calcium levels in the blood

Question 21

T/F any organ that releases a hormone into the blood is part of the endocrine system

Answer 21

True

Question 22

Describe the glucose negative feedback loop

Answer 22

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]

Question 23

T/F a positive feedback loop can only be interrupted or broken by an external signal

Answer 23

True

Question 24

What are the three major classes of hormones

Answer 24

1.) steroid hormones
2.) amine hormones
3.) peptide hormones

Question 25

T/F steroid hormones are hydrophilic

Answer 25

False: they are hydrophobic, peptide and amine hormones are hydrophilic

Question 26

T/F all steroid hormones are derived from cholesterol

Answer 26

True

Question 27

T/F steroid hormones are the most abundant hormone

Answer 27

False: peptide hormones are the most abundant

Question 28

T/F peptide hormones and amine hormones both derived from amino acids

Answer 28

True

Question 29

This hormone is derived from a single aromatic amino acid

Answer 29

amine hormone

Question 30

this hormone is a short chain of amino acids

Answer 30

peptide hormones

Question 31

T/F hormones can only influence those cell types that express the receptor for that hormone

Answer 31

True

Question 32

What hormones rely on cell-surface receptors

Answer 32

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

Question 33

What hormones rely on intracellular receptors

Answer 33

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

Question 34

T/F hormones are typically released in large amounts

Answer 34

False: small

Question 35

T/F Hormonal signaling pathways between endocrine glands and tissues are referred to as endocrine axes

Answer 35

True

Question 36

T/F at each step, the hormonal signal can be amplified.

Answer 36

true

Question 37

T/F the vertebrate endocrine system is localized in one part of the body

Answer 37

False: it is present all throughout; some targets have exclusively endocrine functions but many other tissues/organs keep endocrine cells that secrete hormones

Question 38

T/F the anterior pituitary gland releases oxytocin and ADH

Answer 38

False: the posterior does

Question 39

T/F the anterior pituitary gland communicates to the adrenal gland

Answer 39

True

Question 40

Main difference between anterior and posterior pituitary gland

Answer 40

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

Question 41

T/F the posterior pituitary gland is part of the nervous system

Answer 41

True

Question 42

Hormones that control the release of other hormones are called

Answer 42

tropic hormones
ex.)
AP - TSH - Thyroid gland = metabolic hormones
AP - FSH and LH - Ovaries
= estrogen and progesterone