Unit 2: Cell Signaling

Question 1

Cell Signaling

Answer 1

communication between cells to coordinate responses

Question 2

Steps of cell signaling (5)

Answer 2

signal, reception, transduction, response, and termination.

Question 3

Ligands

Answer 3

A molecule that binds to another specific molecule, in some cases delivering a signal

Question 4

Receptors

Answer 4

Proteins in target cells that bind specific ligands

Question 5

Signal Transduction

Answer 5

Process of converting extracellular signals into intracellular responses in the cytoplasm.

Question 6

Response

Answer 6

Cellular reaction to the signal received

Question 7

Termination

Answer 7

End of the signaling process to stop the cellular response

Question 8

Types of ligands involved in signaling (2)

Answer 8

small hydrophobic ligands and water-soluble ligands

Question 9

Small Hydrophobic Ligands are __ ligands that __ through the plasma membrane.

Answer 9

Lipid-soluble ligands, diffuse (steroid hormones)

Question 10

Water-Soluble Ligands

Answer 10

Polar ligands binding to cell-surface receptors

Question 11

Types of water soluble ligands

Answer 11

small molecules, peptides, and proteins.

Question 12

We can divide receptors into two main classes,

Answer 12

intracellular and cell-surface receptors.

Question 13

Intracellular Receptors

Answer 13

Proteins in the cytoplasm responding to hydrophobic ligands

Question 14

When a ligand binds to an intracellular receptor a ___ occurs that exposes a ___. on the protein. The ligand-receptor complex moves into the ___then binds to specific regulatory regions of the chromosomal DNA and promotes the initiation of __.

Answer 14

conformational change, DNA-binding site, nucleus, transcription

Question 15

Intracellular receptors can directly influence gene expression without having to

Answer 15

pass the signal on to other receptors or messengers.

Question 16

Cell-Surface Receptors (transmembrane receptors)

Answer 16

Membrane proteins binding external ligands for signal transduction

Question 17

Properties of a cell surface receptor (3)

Answer 17

extracellular, hydrophobic transmembrane, and intracellular domain

Question 18

Signaling found in multicellular organisms can be divided into three main classes:

Answer 18

direct, paracrine, and endocrine signaling

Question 19

Direct Signaling

Answer 19

Cell communication through direct contact between cells

Question 20

Specialized types of direct signaling include (3)

Answer 20

juxtacrine, gap junctions, and plasmodesmata

Question 21

Juxtacrine Signaling

Answer 21

Direct signaling between cells via direct contact between membrane-bound ligands

Question 22

Gap Junctions

Answer 22

Connections between neighboring cell membranes

Question 23

Plasmodesmata

Answer 23

Connections in plants between neighboring cell membranes

Question 24

Paracrine Signaling

Answer 24

Local signals between nearby cells via diffusion through extracellular matrix

Question 25

Specialized types of paracrine signaling (2)

Answer 25

autocrine and neuronal signaling

Question 26

Autocrine Signaling

Answer 26

Signals produced by cells binding to released ligands, influencing self or similar cells

Question 27

Neuronal Signaling

Answer 27

Transmission of signals between neurons and target cells through synapses

Question 28

synaptic signal

Answer 28

a chemical signal that travels between nerve cells.

Question 29

Synaptic signal process

Answer 29

Signals within the nerve cells are propagated by fast-moving electrical impulses. When these impulses reach the end of the axon, the signal continues on to a dendrite of the next cell by the release of chemical ligands called neurotransmitters from the presynaptic cell (the cell emitting the signal).

Question 30

Endocrine Signaling

Answer 30

Signals from distant endocrine cells affecting target cells via hormones in the bloodstream

Question 31

The ligands released in endocrine signaling are called

Answer 31

hormones

Question 32

a signaling molecule that regulates physiology, behavior, or development

Answer 32

Hormone

Question 33

Hormone transportation

Answer 33

travel the large distances between endocrine cells and their target cells via the bloodstream

Question 34

Why do hormones present in low concentrations

Answer 34

they become diluted by the time they reach their target cell, due to their long distance of travel

Question 35

Types of hormones include; (4)

Answer 35

amine, peptide, protein, steroid

Question 36

Signal transduction

Answer 36

Once a ligand binds to a receptor, the signal is transmitted through the membrane and into the cytoplasm (and sometimes also the nucleus) of the cell

Question 37

When a ligand binds to its receptor, ___ occur that affect the receptor's intracellular domain

Answer 37

conformational changes

Question 38

Signaling Pathway (signaling cascade)

Answer 38

Chain of events triggered by receptor activation, leading to cellular changes

Question 39

Methods of intracellular signaling include; (2)

Answer 39

phosphorylation and second messengers

Question 40

Second Messengers (2)

Answer 40

Enzymes and proteins in a signaling cascade interacting with specific proteins

Question 41

Examples of second messengers

Answer 41

calcium ions and cAMP (cyclic AMP)

Question 42

Calcium signaling

Answer 42

a calcium ion is a widely used second messenger that regulates various cellular responses

Question 43

Phosphorylation

Answer 43

Common modification adding phosphate groups to proteins, often catalyzed by kinases

Question 44

Kinase

Answer 44

Enzyme catalyzing the transfer of a phosphate group

Question 45

Dephosphorylation

Answer 45

Removal of a phosphate group from a protein, reversing its activation

Question 46

Cyclic AMP (cAMP)

Answer 46

Second messenger synthesized from ATP, activating A-kinase

Question 47

Response to signal is determined by

Answer 47

external/internal conditions and cell type

Question 48

Common responses to cell signaling include;

Answer 48

gene expression, increase in cellular metabolism, cell growth & death, and termination of the signal.

Question 49

Gene expression is regulated by

Answer 49

RNA transcription or protein translation by signaling pathways

Question 50

MAPK/ERK Pathway

Answer 50

Protein chain signaling from cell surface receptor to nuclear DNA

Question 51

Cell Growth Factors

Answer 51

Ligands promoting cell division, binding to RTKs and activating MAP kinase pathway

Question 52

Apoptosis

Answer 52

Programmed cell death mechanism to eliminate damaged or unnecessary cells

Question 53

Termination of signal is done by

Answer 53

degrading ligands or reversing cellular modifications

Question 54

Functions of nucleic acids

Answer 54

They carry the cell's genetic blueprint and carry instructions for its functioning.

Question 55

nucleic acids are the most important___ for the continuity of life

Answer 55

macromolecules

Question 56

Main groups of nucleic acids (2)

Answer 56

RNA and DNA

Question 57

ribonucleic acid (RNA)

Answer 57

a nucleic acid that is involved in gene expression and regulation

Question 58

deoxyribonucleic acid (DNA)

Answer 58

nucleic acid that stores genetic information in its sequence of nucleotides

Question 59

DNA in eukaryotic cells is not

Answer 59

enclosed in a membrane-bound organelle.

Question 60

RNA that carries information from DNA to ribosomes to enable protein synthesis

Answer 60

Messenger RNA (mRNA)

Question 61

ribosomal RNA (rRNA), transfer RNA (tRNA), and microRNA (miRNA) — are types of RNA involved in

Answer 61

protein synthesis and its regulation.

Question 62

specific signal transduction pathway takes place in the__ domain

Answer 62

Intracellular