p.10
Importance of Cellular Communication in Body Functions
What are neurotransmitters?
Chemicals secreted by neurons that diffuse across a small gap to the target cell.
p.65
Signal Transduction Mechanisms
What are some activators of signal transduction pathways?
Ions, gases, small peptides, protein hormones, metabolites, and steroids.
p.1
Cell Junctions and Their Functions
What is the primary function of intercellular junctions?
To facilitate communication and adhesion between adjacent cells.
p.8
Types of Cell Signaling: Autocrine, Paracrine, and Endocrine
What are autocrine signals?
Signals that act on the same cell that secreted them.
p.5
Importance of Cellular Communication in Body Functions
What is the primary method of communication between cells?
Chemical signaling through molecules.
p.37
Signal Transduction Mechanisms
Why do receptors, enzymes, and transporters exhibit specificity?
They are designed to bind specific substrates or ligands based on their shape and chemical properties.
p.54
Signal Transduction Mechanisms
What triggers the activation of protein kinase A?
Activation of adenylyl cyclase leads to an increase in cytosolic cAMP.
p.44
Importance of Cellular Communication in Body Functions
What significant event is associated with 12 July?
The date may refer to various historical events, but specific context is needed to identify a particular one.
p.40
Signal Transduction Mechanisms
What role does nitric oxide play in cellular signaling?
It acts as a signaling molecule that can influence various cellular processes.
p.23
Importance of Cellular Communication in Body Functions
What is the primary function of cell communication?
Cells respond to external signals.
p.3
Importance of Cellular Communication in Body Functions
What project did the NIH embark on in 2003?
To promote translation of basic research into new medical treatments and strategies for disease prevention.
p.64
Importance of Cellular Communication in Body Functions
What is the purpose of expressing gratitude?
To acknowledge kindness or help received.
p.45
Signal Transduction Mechanisms
What pathway is activated by tyrosine kinase receptors?
The mitogen-activated protein kinase pathway.
p.58
Role of Second Messengers in Signal Amplification
What is the concentration of cytosolic calcium in an unstimulated cell compared to the extracellular fluid (ECF)?
About 10,000 times lower (10^-7 M vs. 10^-3 M).
p.16
Cell Junctions and Their Functions
What are tight junctions?
Specialized connections between adjacent cells that prevent the passage of molecules and ions through the space between cells.
p.4
Importance of Cellular Communication in Body Functions
What is electrical signaling in cells?
Changes in a cell’s membrane potential.
p.23
Signal Transduction Mechanisms
What is transduction in cell signaling?
Cascades of molecular interactions.
p.33
Cell Junctions and Their Functions
What do ion channel receptors do?
They open or close gates.
p.12
Importance of Cellular Communication in Body Functions
What is one method of direct cell communication?
Direct contact between membrane-bound cell-surface molecules.
p.6
Gap Junctions and Intercellular Communication
What is one method of local communication between cells?
Gap junctions allow direct cytoplasmic transfer of electrical and chemical signals.
p.65
Signal Transduction Mechanisms
What is a hallmark of cellular signaling?
It is regulated by various mechanisms to activate and terminate signal transduction.
p.15
Cell Junctions and Their Functions
What are cell junctions?
Structures that connect cells to each other and to the extracellular matrix.
p.2
Role of Second Messengers in Signal Amplification
How do second messengers function in signal transduction?
They regulate and amplify signal transduction.
p.15
Cell Junctions and Their Functions
What is the function of tight junctions?
To prevent the passage of molecules and ions through the space between cells.
p.33
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
What is the function of receptor tyrosine kinases?
They have enzymatic activity and catalyze the transfer of phosphate groups.
p.54
Signal Transduction Mechanisms
What can the active catalytic subunits of protein kinase A phosphorylate?
Target enzymes, ion channels, or transcription factors.
p.7
Importance of Cellular Communication in Body Functions
What do contact-dependent signals require?
Interaction between membrane molecules on two cells.
p.65
Importance of Cellular Communication in Body Functions
Why is cellular communication essential?
To integrate and coordinate the systems of the body for different functions.
p.37
Signal Transduction Mechanisms
What common characteristic do receptors, enzymes, and transporters share that leads to saturation?
They all have a limited number of binding sites.
p.15
Cell Junctions and Their Functions
What are the main types of cell junctions?
Tight junctions, adherens junctions, desmosomes, gap junctions.
p.58
Signal Transduction Mechanisms
What triggers the opening of voltage-gated Ca channels?
When the plasma membrane depolarizes or through PKA or PKC phosphorylation.
p.45
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
How do tyrosine kinase receptors signal?
Through adapter proteins.
p.40
Signal Transduction Mechanisms
What is the primary action of steroid and thyroid hormones at the genomic level?
They regulate gene expression.
p.40
Signal Transduction Mechanisms
How do intracellular receptors initiate genomic action?
By binding to specific DNA sequences and influencing transcription.
p.33
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
What type of receptors can have inhibitory or excitatory activity?
G protein coupled receptors.
p.46
Role of Second Messengers in Signal Amplification
What is the primary function of second messengers?
To amplify the signal from a receptor to elicit a cellular response.
p.17
Cell Junctions and Their Functions
What are anchoring junctions?
Cell structures that connect adjacent cells to each other and to the extracellular matrix.
p.58
Role of Second Messengers in Signal Amplification
How does calcium act as a second messenger?
By binding directly to an effector target like PKC or to an intermediary protein like calmodulin.
p.16
Cell Junctions and Their Functions
How do tight junctions contribute to cellular communication?
By maintaining the polarity of cells and controlling the flow of ions and small molecules.
p.18
Gap Junctions and Intercellular Communication
What are gap junctions?
Direct cytoplasmic connections between adjacent cells.
p.8
Types of Cell Signaling: Autocrine, Paracrine, and Endocrine
What are paracrine signals?
Signals that are secreted by one cell and diffuse to adjacent cells.
p.5
Types of Cell Signaling: Autocrine, Paracrine, and Endocrine
What are the three main types of cell signaling?
Autocrine, paracrine, and endocrine signaling.
p.59
Role of Second Messengers in Signal Amplification
What is the role of calcium (Ca) in intracellular signaling?
Calcium acts as a second messenger in various signaling pathways.
p.5
Types of Cell Signaling: Autocrine, Paracrine, and Endocrine
What is autocrine signaling?
A type of signaling where a cell targets itself.
p.37
Signal Transduction Mechanisms
How does saturation affect the function of receptors, enzymes, and transporters?
Once all binding sites are occupied, increasing the concentration of the substrate or ligand does not increase the rate of reaction or response.
p.59
Signal Transduction Mechanisms
What is calmodulin?
A calcium-binding messenger protein that mediates the effects of calcium in cells.
p.13
Cell Junctions and Their Functions
What are the main types of cell junctions?
Tight junctions, adherens junctions, desmosomes, gap junctions, and hemidesmosomes.
p.10
Importance of Cellular Communication in Body Functions
How do neurotransmitters reach their target cells?
By diffusing across a small gap.
p.2
Gap Junctions and Intercellular Communication
What is the role of gap junctions and plasma membrane receptors?
They regulate communications between cells.
p.54
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
What is the composition of inactive protein kinase A?
It consists of 2 regulatory subunits (R) complexed with 2 catalytic subunits (C).
p.37
Signal Transduction Mechanisms
What does competition refer to in the context of receptors, enzymes, and transporters?
The ability of different molecules to bind to the same site, affecting the function of the receptor, enzyme, or transporter.
p.54
Role of Second Messengers in Signal Amplification
What happens when 2 cAMP binds to the regulatory subunits of protein kinase A?
It causes the release of the active catalytic subunit.
p.5
Types of Cell Signaling: Autocrine, Paracrine, and Endocrine
What is endocrine signaling?
A type of signaling where hormones are released into the bloodstream to target distant cells.
p.4
Importance of Cellular Communication in Body Functions
What are target cells?
Cells that respond to electrical or chemical signals.
p.10
Importance of Cellular Communication in Body Functions
What is the role of neurotransmitters in the nervous system?
They facilitate long-distance communication by transmitting signals between neurons and target cells.
p.65
Cell Junctions and Their Functions
Where are receptors located in relation to signaling molecules?
On the plasma membrane or within the cell.
p.33
Signal Transduction Mechanisms
What happens to a receptor upon binding with a ligand?
It undergoes a change of shape, leading to activation and the ability to transfer a signal.
p.1
Gap Junctions and Intercellular Communication
What are gap junctions?
Specialized intercellular connections that allow direct communication between cells.
p.59
Signal Transduction Mechanisms
What activates Ca-calmodulin-dependent protein kinases?
The binding of calcium to calmodulin activates these kinases.
p.3
Importance of Cellular Communication in Body Functions
How many cells are in the human body?
Approximately 75 trillion cells.
p.16
Cell Junctions and Their Functions
Where are tight junctions commonly found?
In epithelial tissues, such as the lining of the intestines and blood-brain barrier.
p.23
Signal Transduction Mechanisms
What is the outcome of signaling in cells?
Regulation of transcription or cytoplasmic activities.
p.14
Cell Junctions and Their Functions
What are epithelial cell junctions?
Structures that connect epithelial cells to each other and to the underlying tissue.
p.5
Signal Transduction Mechanisms
What is signal transduction?
The process by which a cell responds to external signals.
p.60
Phosphodiesterases and Their Clinical Relevance
Why are cyclic nucleotide PDEs important in a clinical setting?
They control the cellular levels of the second messengers, cAMP and cGMP, and the signal transduction pathways modulated by these.
p.14
Cell Junctions and Their Functions
What role do adherens junctions play?
They provide mechanical stability by linking the cytoskeletons of adjacent cells.
p.19
Gap Junctions and Intercellular Communication
What types of molecules can pass through gap junctions?
Ions, small metabolites, and signaling molecules.
p.63
Signal Transduction Mechanisms
What are some activators of signal transduction pathways?
Ions, gases, small peptides, protein hormones, metabolites, and steroids.
p.19
Gap Junctions and Intercellular Communication
In which types of tissues are gap junctions commonly found?
Cardiac and smooth muscle tissues, as well as in some epithelial tissues.
p.51
Signal Transduction Mechanisms
What does the activation of G protein lead to?
Stimulation of phospholipase C (PLC) and hydrolysis of PIP2.
p.50
Role of Second Messengers in Signal Amplification
What is the role of nitric oxide (NO) in smooth muscle relaxation?
It diffuses into smooth muscles to increase cGMP, activating PKG and ion channels, which reduce cytoplasmic Ca2+.
p.18
Gap Junctions and Intercellular Communication
What is the primary function of gap junctions?
To allow direct communication and transfer of ions and small molecules between adjacent cells.
p.2
Types of Cell Signaling: Autocrine, Paracrine, and Endocrine
What are the three types of signaling compared in cell function control?
Autocrine, paracrine, and endocrine signaling.
p.46
Role of Second Messengers in Signal Amplification
What are second messengers?
Intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules.
p.23
Signal Transduction Mechanisms
What happens when a signaling molecule binds to a receptor protein?
It causes the receptor protein to change shape.
p.58
Signal Transduction Mechanisms
What are the two main types of Ca ion channels in the endoplasmic reticulum?
1. IP3-gated Ca release channel 2. Ryanodine receptor.
p.4
Importance of Cellular Communication in Body Functions
What are chemical signals?
Molecules secreted by cells into the extracellular fluid (ECF).
p.17
Cell Junctions and Their Functions
What is the primary function of anchoring junctions?
To provide mechanical stability and strength to tissues.
p.60
Phosphodiesterases and Their Clinical Relevance
What is the function of phosphodiesterase (PDE)?
It hydrolyzes a phosphodiester bond.
p.4
Importance of Cellular Communication in Body Functions
What role do chemical signals play in the body?
They are responsible for most communication within the body.
p.4
Importance of Cellular Communication in Body Functions
How do chemical signals initiate a response?
By acting as ligands that bind to proteins.
p.60
Phosphodiesterases and Their Clinical Relevance
What role do nitrates play in relation to nitric oxide (NO)?
Nitrates act as an exogenous source of NO, stimulating soluble guanylate cyclases (GCs) to increase cGMP, leading to vasodilation.
p.14
Cell Junctions and Their Functions
What are desmosomes?
Specialized structures that provide strong adhesion between cells.
p.43
Signal Transduction Mechanisms
What is phosphorylated in tyrosine kinase receptor activation?
Tyrosine residues in the receptor and other target proteins.
p.51
Role of Second Messengers in Signal Amplification
What are diacylglycerol and inositol trisphosphate derived from?
Lipid in the plasma membrane.
p.9
Types of Cell Signaling: Autocrine, Paracrine, and Endocrine
What are the two types of long-distance signaling?
Electrical signals along neurons and chemical signals through the circulatory system.
p.2
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
What are the major differences between G-protein-coupled receptors and tyrosine kinase receptors?
They differ in their mechanisms of intracellular signal transduction.
p.5
Types of Cell Signaling: Autocrine, Paracrine, and Endocrine
What is paracrine signaling?
A type of signaling where a cell targets nearby cells.
What determines which cells respond to a hormone signal?
Only target cells with receptors for the hormone respond.
p.46
Importance of Cellular Communication in Body Functions
How do second messengers contribute to cellular communication?
They relay signals from receptors on the cell surface to target molecules inside the cell.
p.12
Importance of Cellular Communication in Body Functions
What role do cell junctions play in cell communication?
They facilitate cell-cell recognition.
p.5
Role of Second Messengers in Signal Amplification
What are second messengers?
Intracellular molecules that amplify the signal from receptors.
p.4
Importance of Cellular Communication in Body Functions
What rules do protein bindings of chemical signals obey?
Specificity, affinity, competition, and saturation.
p.60
Phosphodiesterases and Their Clinical Relevance
What conditions can be treated with PDE5 inhibitors?
Erectile dysfunction and pulmonary hypertension.
p.48
Phosphodiesterases and Their Clinical Relevance
What can activate phosphodiesterases (PDEs)?
Increased cyclic nucleotides or other signal transduction processes.
p.51
Signal Transduction Mechanisms
Where is phospholipase C (PLC) localized?
To the inner leaflet of the plasma membrane.
How are hormones transported in the body?
They are secreted by endocrine glands or cells into the blood.
p.15
Cell Junctions and Their Functions
What role do gap junctions play?
They allow for direct communication between adjacent cells.
p.1
Cell Junctions and Their Functions
What role do desmosomes play in cell communication?
They provide mechanical stability and can influence signaling pathways between cells.
p.54
Importance of Cellular Communication in Body Functions
What is the result of the phosphorylation by protein kinase A?
It results in a cellular response.
p.3
Importance of Cellular Communication in Body Functions
What fields of research help us understand cell communication?
Proteomics and metabolomics.
p.14
Cell Junctions and Their Functions
What is the function of tight junctions?
To prevent the passage of molecules and ions through the space between cells.
p.63
Importance of Cellular Communication in Body Functions
Why is cellular communication important?
It integrates and coordinates the systems of the body for different functions.
p.43
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
What types of factors activate tyrosine kinase receptors?
Insulin and growth factors (such as epidermal, fibroblast, and PDGF).
p.53
Signal Transduction Mechanisms
What is the role of the activated G protein in signal transduction?
It activates or inhibits downstream effectors, such as enzymes or ion channels.
p.48
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
Which proteins are activated by some hormones to inhibit cAMP production?
Inhibitory G proteins (Gαi).
p.51
Role of Second Messengers in Signal Amplification
What are the products of PIP2 hydrolysis?
Diacylglycerol (DAG) and inositol trisphosphate (IP3).
p.1
Cell Junctions and Their Functions
How do tight junctions contribute to cell communication?
They create a barrier that regulates the passage of substances between cells, influencing signaling.
p.13
Cell Junctions and Their Functions
What are cell junctions?
Structures that connect cells to each other and to the extracellular matrix.
p.3
Types of Cell Signaling: Autocrine, Paracrine, and Endocrine
What are the two basic types of physiological signals?
Electrical and chemical signals.
p.5
Signal Transduction Mechanisms
What role do receptors play in cell communication?
Receptors bind signaling molecules and initiate a response in the target cell.
p.11
Importance of Cellular Communication in Body Functions
What are neurohormones?
Chemicals released by neurons into the blood for action at distant targets.
p.11
Importance of Cellular Communication in Body Functions
What type of communication do neurohormones facilitate?
Long distance communication.
p.13
Cell Junctions and Their Functions
What is the purpose of adherens junctions?
To connect the actin cytoskeleton of one cell to that of another.
p.12
Importance of Cellular Communication in Body Functions
What are two key processes that involve cell communication?
Embryo development and immune response.
p.14
Cell Junctions and Their Functions
What are hemidesmosomes?
Structures that anchor epithelial cells to the basement membrane.
p.51
Role of Second Messengers in Signal Amplification
What role do DAG and IP3 serve in the cell?
They act as second messengers.
p.16
Cell Junctions and Their Functions
What is the primary function of tight junctions?
To create a barrier that regulates the movement of substances between cells.
p.2
Regulation of Intracellular Calcium Concentration
How is intracellular calcium concentration regulated?
It is regulated and used in intracellular signal transduction.
p.15
Cell Junctions and Their Functions
What is the purpose of desmosomes?
To provide mechanical strength by anchoring adjacent cells together.
p.1
Importance of Cellular Communication in Body Functions
What is the significance of cell-to-cell communication in tissues?
It is essential for coordinating functions and responses among cells in a tissue.
p.59
Regulation of Intracellular Calcium Concentration
How does calcium concentration affect cellular signaling?
Changes in calcium concentration can trigger different signaling pathways and cellular responses.
p.48
Role of Second Messengers in Signal Amplification
What is the role of second messengers in cell signaling?
They are important for amplification and flow of the signal received by plasma membrane receptors.
p.48
Role of Second Messengers in Signal Amplification
What is the predominant second messenger in all cells?
cAMP (cyclic adenosine monophosphate).
p.53
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
What initiates the activation of a G protein-coupled receptor (GPCR)?
The binding of a ligand to the receptor.
p.19
Gap Junctions and Intercellular Communication
How do gap junctions contribute to tissue function?
They synchronize cellular activities and coordinate responses in tissues.
p.43
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
What is a key feature of tyrosine kinase receptors?
They have an intrinsic tyrosine kinase or associate with a cytoplasmic tyrosine kinase when activated.
p.53
Phosphodiesterases and Their Clinical Relevance
What happens to cAMP levels when the G protein is deactivated?
cAMP levels decrease as phosphodiesterases break it down.
p.59
Signal Transduction Mechanisms
What is the significance of Ca-calmodulin-dependent protein kinases?
They play a crucial role in various cellular processes by phosphorylating target proteins.
p.58
Role of Second Messengers in Signal Amplification
What is the role of calmodulin in calcium signaling?
It acts as an intermediary cytosolic Ca-binding protein.
p.19
Gap Junctions and Intercellular Communication
What are gap junctions?
Specialized intercellular connections that allow direct communication between adjacent cells.
p.19
Gap Junctions and Intercellular Communication
What is the primary function of gap junctions?
To facilitate the transfer of ions and small molecules between cells.
p.63
Signal Transduction Mechanisms
What characterizes cellular signaling?
It is regulated by various mechanisms to activate and terminate signal transduction.
p.48
Phosphodiesterases and Their Clinical Relevance
How is cAMP terminated in the cell?
By hydrolysis to 5′AMP by phosphodiesterases (PDEs).
p.63
Role of Second Messengers in Signal Amplification
What is the role of second messengers in cellular signaling?
They are important for amplification and flow of the signal received by plasma membrane receptors.
p.50
Role of Second Messengers in Signal Amplification
What are cGMP and NO classified as in cellular signaling?
Important second messengers in smooth muscle and sensory cells.
p.9
Importance of Cellular Communication in Body Functions
What is the primary function of hormones in long-distance communication?
To signal target cells that have specific receptors.
p.23
Signal Transduction Mechanisms
What are signal transduction pathways?
They are the routes through which signaling leads to cellular responses.
p.12
Types of Cell Signaling: Autocrine, Paracrine, and Endocrine
What are two types of local regulators in cell signaling?
Autocrine and paracrine signaling.
p.60
Phosphodiesterases and Their Clinical Relevance
What is the mechanism of action of Sildenafil (Viagra)?
It is a PDE5 inhibitor used to treat erectile dysfunction and pulmonary hypertension.
p.14
Cell Junctions and Their Functions
What is the purpose of gap junctions?
To allow communication and transfer of small molecules between adjacent cells.
p.53
Cyclic Nucleotides: cAMP and cGMP
How is cyclic adenosine monophosphate (cAMP) produced?
Through the activation of adenylate cyclase by the G protein.
p.51
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
What happens when a ligand binds to a GPCR?
It activates a G protein, usually Gαq.
p.50
Role of Second Messengers in Signal Amplification
How does cGMP affect ion channels and pumps?
It can directly activate them to modulate cytoplasmic calcium.
p.50
Phosphodiesterases and Their Clinical Relevance
What is the significance of phosphodiesterases (PDE) in relation to cGMP?
They regulate the levels of cGMP and can be inhibited to enhance its effects.
p.15
Cell Junctions and Their Functions
How do adherens junctions contribute to cell structure?
They connect the actin cytoskeleton of one cell to that of another.
p.3
Importance of Cellular Communication in Body Functions
What is the challenge faced by cells in the body regarding communication?
To communicate rapidly while conveying a tremendous amount of information.
p.3
Importance of Cellular Communication in Body Functions
Can each cell in the body communicate with other cells?
Yes, each cell can communicate with most other cells.
p.17
Cell Junctions and Their Functions
How do anchoring junctions contribute to tissue integrity?
By linking the cytoskeletons of adjacent cells, they help maintain the structural integrity of tissues.
p.48
Signal Transduction Mechanisms
What is the process that leads to the production of cAMP?
Stimulatory G proteins activate adenylate cyclase (AC), which converts ATP to cAMP.
p.19
Gap Junctions and Intercellular Communication
What proteins form gap junctions?
Connexins, which assemble to form connexons.
p.43
Importance of Cellular Communication in Body Functions
What cellular processes are influenced by activated tyrosine kinase receptors?
Transcription of genes, growth, cellular differentiation, and movements (such as crawling and shape change).
p.50
Role of Second Messengers in Signal Amplification
What does the activation of PKG lead to in smooth muscle cells?
Smooth muscle relaxation.
p.13
Cell Junctions and Their Functions
What is the function of tight junctions?
To create a barrier that prevents the passage of molecules between cells.
p.13
Cell Junctions and Their Functions
What role do gap junctions play in cellular communication?
They allow direct communication between adjacent cells through channels.
p.17
Cell Junctions and Their Functions
What role do desmosomes play in anchoring junctions?
They provide strong adhesion between cells, particularly in tissues subject to mechanical stress.
p.13
Cell Junctions and Their Functions
What is the function of hemidesmosomes?
To anchor cells to the extracellular matrix.
p.60
Phosphodiesterases and Their Clinical Relevance
How does sildenafil relate to angina treatment?
It can treat angina but is considered short-acting.
p.53
Role of Second Messengers in Signal Amplification
What is the function of cAMP in cellular signaling?
It acts as a second messenger to amplify the signal and activate protein kinase A (PKA).
p.17
Cell Junctions and Their Functions
What are the two main types of anchoring junctions?
Adherens junctions and desmosomes.
p.13
Cell Junctions and Their Functions
How do desmosomes contribute to tissue integrity?
By providing strong adhesion between cells, resisting mechanical stress.
p.48
Signal Transduction Mechanisms
Which proteins are associated with the stimulation of cAMP production?
Stimulatory G proteins (Gαs).
p.53
G-Protein Coupled Receptors vs. Tyrosine Kinase Receptors
What happens to the G protein upon activation of a GPCR?
It undergoes a conformational change and exchanges GDP for GTP.
p.63
Cell Junctions and Their Functions
Where are receptors located?
On the plasma membrane or within the cell.
p.43
Role of Second Messengers in Signal Amplification
Do tyrosine kinase receptors generate second messengers?
No, they do not generate second messengers like cAMP or cGMP.
