Ch.1 Cellular Biology

The integrity of cells.

Cellular crosstalk

To allow cells to determine their position and specialized role.

<p>The conversation breaks down, leading to cellular adaptation, isolation, injury, disease, or death.</p> Signup and view all the answers

<p>By demonstrating a 'chemical fondness' for other cells and their surrounding environment.</p> Signup and view all the answers

<p>They may alter their function.</p> Signup and view all the answers

<p>Eukaryotes and prokaryotes</p> Signup and view all the answers

<p>A well-defined nucleus</p> Signup and view all the answers

<p>Eukaryotes</p> Signup and view all the answers

<p>Organelles</p> Signup and view all the answers

<p>A single circular chromosome</p> Signup and view all the answers

<p>They bind with DNA and are involved in the supercoiling of DNA</p> Signup and view all the answers

<p>Due to structural differences in RNA-protein complexes</p> Signup and view all the answers

<p>Differences in mechanisms of transport</p> Signup and view all the answers

<p>They have different enzyme contents</p> Signup and view all the answers

<p>Due to their more extensive intracellular anatomy and organization</p> Signup and view all the answers

<p>To generate forces that produce motion</p> Signup and view all the answers

<p>Conductivity, allowing a wave of excitation to pass along the surface of the cell</p> Signup and view all the answers

<p>To reabsorb fluids and synthesize protein enzymes</p> Signup and view all the answers

<p>To reabsorb fluids and synthesize proteins</p> Signup and view all the answers

<p>To synthesize and secrete new substances</p> Signup and view all the answers

<p>Through membrane-bound sacs called lysosomes, which contain enzymes that break down large molecules</p> Signup and view all the answers

<p>To secrete hormonal steroids</p> Signup and view all the answers

<p>Some cells are specialized for movement, while others are specialized for functions like conductivity, metabolic absorption, secretion, or excretion</p> Signup and view all the answers

<p>They lose some other properties, such as hormone production, in favor of a highly developed function</p> Signup and view all the answers

<p>The elimination of waste products through excretion</p> Signup and view all the answers

<p>Nucleolus</p> Signup and view all the answers

<p>Cytosol</p> Signup and view all the answers

<p>Cytoplasmic matrix</p> Signup and view all the answers

<p>To enable simultaneous functions in different biochemical environments</p> Signup and view all the answers

<p>They remain in the cytosol</p> Signup and view all the answers

<p>To store fat, carbohydrate, and secretory vesicles</p> Signup and view all the answers

<p>To carry coded messages from the nucleus to direct cellular activities</p> Signup and view all the answers

<p>About half</p> Signup and view all the answers

<p>Thousands of enzymes</p> Signup and view all the answers

<p>To make proteins</p> Signup and view all the answers

<p>plasma membrane or plasmalemma</p> Signup and view all the answers

<p>to allow molecules to move between the nucleus and the cytosol</p> Signup and view all the answers

<p>to regulate DNA activity by binding to DNA</p> Signup and view all the answers

<p>cell division and control of genetic information</p> Signup and view all the answers

<p>it allows for communication and exchange between the nucleus and the rest of the cell</p> Signup and view all the answers

<p>to prevent DNA breakage and facilitate cell division</p> Signup and view all the answers

<p>it is a small, dense structure composed largely of RNA</p> Signup and view all the answers

<p>resolution to the nanoscale, allowing cells to seem 'alive' with the molecular world more visible</p> Signup and view all the answers

<p>it will reveal how cells respond to mechanical forces and emerge from different gene expression patterns</p> Signup and view all the answers

<p>it is huge, with significant implications for our understanding of biological processes</p> Signup and view all the answers

<p>protein folding</p> Signup and view all the answers

<p>unfolded-protein response (UPR)</p> Signup and view all the answers

<p>secretory vesicles</p> Signup and view all the answers

<p>clathrin-coated vesicle</p> Signup and view all the answers

<p>endoplasmic reticulum (ER)</p> Signup and view all the answers

<p>ER stress</p> Signup and view all the answers

<p>secretory pathway</p> Signup and view all the answers

<p>facilitate protein folding and prevent off-pathway interactions</p> Signup and view all the answers

<p>apoptosis or cell death</p> Signup and view all the answers

<p>diagnosis and treatment of disease</p> Signup and view all the answers

<p>To provide sites for cellular protein synthesis</p> Signup and view all the answers

<p>To bind to the ribosome after recognizing the signal sequence and direct the protein to the endoplasmic reticulum</p> Signup and view all the answers

<p>Rough ER has ribosomes attached to it, while smooth ER does not</p> Signup and view all the answers

<p>To synthesize and transport proteins and lipids</p> Signup and view all the answers

<p>It allows for the transport of proteins and lipids from the ER to the nucleus</p> Signup and view all the answers

<p>To synthesize ribosomes</p> Signup and view all the answers

<p>To allow the transport of molecules between the nucleus and cytoplasm</p> Signup and view all the answers

<p>The ribosome is directed to the endoplasmic reticulum</p> Signup and view all the answers

<p>It is threaded through the ER membrane into the lumen and folded into its final conformation</p> Signup and view all the answers

<p>It plays a new role in sensing cellular stress</p> Signup and view all the answers

<p>The primary function of lysosomes is to break down and recycle cellular waste and foreign substances through the process of digestion and degradation, serving as the cell's 'recycling centers'.</p> Signup and view all the answers

<p>Hydrolases</p> Signup and view all the answers

<p>Acidic pH</p> Signup and view all the answers

<p>Lysosomes play a central role in nutrient-dependent signal transduction for cellular adaptation.</p> Signup and view all the answers

<p>Alterations in lysosomal function are implicated in a range of diseases, including storage diseases, neurodegenerative diseases, and cancer.</p> Signup and view all the answers

<p>Transport proteins in the lysosome membrane carry the final breakdown products to the cytosol for reuse or excretion.</p> Signup and view all the answers

<p>Efficient removal of toxic cellular components, maintenance of metabolic homeostasis, and termination of signal transduction.</p> Signup and view all the answers

<p>Lysosomes play a central role in nutrient-dependent signal transduction for cellular adaptation.</p> Signup and view all the answers

<p>Lysosomes maintain cellular health by removing toxic cellular components, terminating signal transduction, and maintaining metabolic homeostasis.</p> Signup and view all the answers

<p>Lysosomes interact with other organelles, such as the endoplasmic reticulum, to regulate cellular metabolism and adaptation.</p> Signup and view all the answers

<p>To act as a protective shield between the powerful digestive enzymes within the lysosome and the cytoplasm, preventing their leakage into the cytoplasmic matrix.</p> Signup and view all the answers

<p>Cellular self-digestion occurs, which can lead to cellular injury and death.</p> Signup and view all the answers

<p>Pompe disease</p> Signup and view all the answers

<p>Tay-Sachs disease</p> Signup and view all the answers

<p>Endocytosis</p> Signup and view all the answers

<p>Phagocytosis</p> Signup and view all the answers

<p>Autophagy</p> Signup and view all the answers

<p>By pumping hydrogen ions into their interiors</p> Signup and view all the answers

<p>Damage to the lysosomal membrane, leading to enzyme leakage and cell death.</p> Signup and view all the answers

<p>Digestive vacuole</p> Signup and view all the answers

<p>Acidic pH values</p> Signup and view all the answers

<p>Primary lysosomes</p> Signup and view all the answers

<p>Autophagy</p> Signup and view all the answers

<p>Autolysosomes or autophagosomes</p> Signup and view all the answers

<p>Stored in residual bodies</p> Signup and view all the answers

<p>Lipofuscin</p> Signup and view all the answers

<p>Promotes homeostasis and cell turnover</p> Signup and view all the answers

<p>Passed out of the lysosome and reused by the cell</p> Signup and view all the answers

<p>Contribution to disease</p> Signup and view all the answers

<p>When primary lysosomes fuse with a vacuole or other organelle</p> Signup and view all the answers

<p>To detoxify compounds and fatty acids</p> Signup and view all the answers

<p>To oxidize various substrates and break down hydrogen peroxide</p> Signup and view all the answers

<p>Larger and oval or irregular in shape</p> Signup and view all the answers

<p>Peroxisomes and mitochondria</p> Signup and view all the answers

<p>Cellular respiration and energy production</p> Signup and view all the answers

<p>Convoluted to form partitions called cristae</p> Signup and view all the answers

<p>Disease</p> Signup and view all the answers

<p>Necessary for nerve cell myelination</p> Signup and view all the answers

<p>Essential for oxidative phosphorylation</p> Signup and view all the answers

<p>To increase the surface area for oxidative phosphorylation</p> Signup and view all the answers

<p>55%</p> Signup and view all the answers

<p>Enzymatic biochemical reactions</p> Signup and view all the answers

<p>To synthesize proteins</p> Signup and view all the answers

<p>Intermediary metabolism</p> Signup and view all the answers

<p>Excess glucose</p> Signup and view all the answers

<p>To transport and empty their contents outside the cell</p> Signup and view all the answers

<p>Polyribosomes</p> Signup and view all the answers

<p>Free ribosomes</p> Signup and view all the answers

<p>To provide energy and substrates for maintaining cell integrity</p> Signup and view all the answers

<p>Microtubules provide strength to the cell's structure, support and move organelles, facilitate transport of impulses along nerve cells, and have roles in inflammatory and immune responses and hormone secretion.</p> Signup and view all the answers

<p>Mechanotransduction is the process by which cells translate mechanical stimuli into biochemical signals, allowing cells to adapt to their surroundings.</p> Signup and view all the answers

<p>To move substances, such as mucus, toward the throat, where it can be removed by coughing.</p> Signup and view all the answers

<p>Actin filaments, microtubules, and intermediate filaments.</p> Signup and view all the answers

<p>Nine bundles containing three microtubules each.</p> Signup and view all the answers

<p>Through the cytoskeleton, which translates mechanical forces and deformations into biochemical signals.</p> Signup and view all the answers

<p>In the cell cortex, just beneath the plasma membrane.</p> Signup and view all the answers

<p>The cytoskeleton maintains the cell's shape and internal organization, and permits movement of substances within the cell and movement of external projections.</p> Signup and view all the answers

<p>They bridge the cytoplasm from one cell junction to another, supporting and strengthening the sheet of epithelium.</p> Signup and view all the answers

<p>Microtubules are involved in the external movement or motility of some cells.</p> Signup and view all the answers

<p>A 'wave of excitation'.</p> Signup and view all the answers

<p>Mechanotransduction.</p> Signup and view all the answers

<p>To separate and migrate to opposite poles of the cell.</p> Signup and view all the answers

<p>The cytoskeleton provides the structural framework that maintains the cell's shape and internal organization.</p> Signup and view all the answers

<p>To link the interior of the cell to adjacent cells.</p> Signup and view all the answers

<p>Cell stresses that involve adaptations of mechanotransduction are associated with several alterations and diseases, including loss of hearing, cardiovascular disease, muscular dystrophy, and cancer.</p> Signup and view all the answers

<p>Actin filaments, microtubules, and intermediate filaments.</p> Signup and view all the answers

<p>It creates a protective chamber for the cell's DNA.</p> Signup and view all the answers

<p>To enable the movement of sperm cells.</p> Signup and view all the answers

<p>Actin filaments.</p> Signup and view all the answers

<p>repairing the membrane</p> Signup and view all the answers

<p>lipid rafts</p> Signup and view all the answers

<p>responding to extracellular signals</p> Signup and view all the answers

<p>immerse in water</p> Signup and view all the answers

<p>it is impermeable to most water-soluble molecules</p> Signup and view all the answers

<p>important for endocytosis</p> Signup and view all the answers

<p>phospholipids</p> Signup and view all the answers

<p>amphipathic</p> Signup and view all the answers

<p>components of the cellular environment move slowly and selectively across the membrane</p> Signup and view all the answers

<p>acting as 'molecular glue' for the structural integrity of the membrane</p> Signup and view all the answers

<p>They can allow or exclude various molecules, and move molecules in or out of the space through selective transport systems.</p> Signup and view all the answers

<p>They facilitate directional transport by creating distinct apical and basolateral domains.</p> Signup and view all the answers

<p>They act as markers that identify a cell to its neighbors.</p> Signup and view all the answers

<p>The lipid bilayer, composed of two continuous opposing leaflets and proteins that span the bilayer or interact with the lipids on either side of the two leaflets.</p> Signup and view all the answers

<p>They mediate most of the functions of the membrane, including transport of molecules across the membrane and ATP synthesis.</p> Signup and view all the answers

<p>It maintains normal cell and tissue structure for numerous functions, most importantly transport of nutrients in and out of the cell.</p> Signup and view all the answers

<p>It assists with cellular mobility and maintenance of cellular shape.</p> Signup and view all the answers

<p>It provides the basic fluid structure of the membrane and is mostly an impermeable barrier to water-soluble molecules.</p> Signup and view all the answers

<p>They can diffuse readily throughout their own monolayer.</p> Signup and view all the answers

<p>They exert a powerful influence on metabolic pathways by controlling the movement of substances from one compartment to another.</p> Signup and view all the answers

<p>Proteins act as receptors, enzymes, or transporters, serving as recognition and binding units, pores or transport channels, specific enzymes, cell surface markers, cell adhesion molecules, and catalysts of chemical reactions.</p> Signup and view all the answers

<p>Proteostasis</p> Signup and view all the answers

<p>They help refold misfolded proteins, facilitate transportation, and ubiquitinate proteins for degradation.</p> Signup and view all the answers

<p>Proteins remain in the cytosol permanently.</p> Signup and view all the answers

<p>Vesicles discharge their cargo into a different compartment by fusing with that compartment's membrane.</p> Signup and view all the answers

<p>Misfolded proteins can cause disease, and understanding protein trafficking and misfolded proteins can provide insights into disease mechanisms.</p> Signup and view all the answers

<p>The proteostasis network regulates protein homeostasis under various conditions, including nutrient supply variation, oxidative stress, cellular differentiation, temperature changes, and heavy metal ion presence.</p> Signup and view all the answers

<p>Proteins act as cell adhesion molecules (CAMs), allowing cells to hook together and form attachments to the cytoskeleton.</p> Signup and view all the answers

<p>It is associated with human disease.</p> Signup and view all the answers

<p>Membrane proteins are key components of energy transduction, converting chemical energy into electrical energy or mechanical energy.</p> Signup and view all the answers

<p>Membrane proteins associate with the lipid bilayer in different ways, including transmembrane proteins, proteins located almost entirely in the cytosol, proteins existing outside the bilayer, and proteins bound indirectly to one or the other bilayer membrane face.</p> Signup and view all the answers

<p>The amino acid sequence contains sorting signals that direct the delivery of proteins to locations outside the cytosol or to organelle surfaces.</p> Signup and view all the answers

<p>Gated transport, protein translocation, and vesicular transport.</p> Signup and view all the answers

<p>Nuclear pore complexes direct the movement of proteins and RNA molecules between the cytosol and the nucleus.</p> Signup and view all the answers

<p>Membrane proteins are amphiphilic, with both hydrophobic and hydrophilic regions.</p> Signup and view all the answers

<p>Proteins fold into densely folded molecular configurations, with an excess of hydrophilic units at the surface and an excess of hydrophobic units inside.</p> Signup and view all the answers

<p>Ribosomes synthesize proteins mainly in the cytosol.</p> Signup and view all the answers

<p>The unique sequence of amino acids determines the specific function of each protein.</p> Signup and view all the answers

<p>The cytosol is the site where proteins are synthesized and trafficked to their destinations.</p> Signup and view all the answers

<p>The interaction between proteins and the lipid bilayer is crucial for membrane protein function and cell signaling.</p> Signup and view all the answers

<p>Breakdown of proteins.</p> Signup and view all the answers

<p>Glycocalyx (or cell coat).</p> Signup and view all the answers

<p>Cell death or caspase-mediated apoptosis, the blood coagulation cascade, degrading membrane enzymes or matrix metalloproteinase cascade, and the complement cascade.</p> Signup and view all the answers

<p>Protection from mechanical damage and assistance in cell mobility.</p> Signup and view all the answers

<p>They contain short chains of sugars or carbohydrates (oligosaccharides) that are involved in cell-cell recognition and adhesion.</p> Signup and view all the answers

<p>It features prominently in many human diseases, including cancer, autoimmunity, and neurodegenerative disorders.</p> Signup and view all the answers

<p>It participates in specific cell-cell recognition and adhesion.</p> Signup and view all the answers

<p>They participate in a tightly orchestrated sequence of events, acting as initiators, amplifiers, and executors.</p> Signup and view all the answers

<p>It leads to many human diseases, including cancer, autoimmunity, and neurodegenerative disorders.</p> Signup and view all the answers

<p>It helps protect the cell from mechanical damage.</p> Signup and view all the answers

<p>Lectins recognize and bind to specific oligosaccharides on neutrophils, allowing them to adhere to the blood vessel wall and migrate to the infected tissue to eliminate the invading bacteria.</p> Signup and view all the answers

<p>The binding site is the region of a protein receptor that associates with a ligand, and they interact through formation of weak, noncovalent interactions, such as hydrogen bonds, electrostatic attractions, and van der Waals attractions, and favorable hydrophobic forces.</p> Signup and view all the answers

<p>Plasma membrane receptors determine which ligands a cell will bind with and how the cell will respond to binding, regulating the cell's response to hormones, neurotransmitters, and other molecules.</p> Signup and view all the answers

<p>Receptors for endorphins and opiates change the cell's permeability to ions, increase the concentration of molecules that regulate intracellular protein synthesis, and initiate molecular events that modulate pain perception.</p> Signup and view all the answers

<p>Antigen receptors on white blood cells recognize and bind with antigenic microorganisms, activating the immune and inflammatory responses.</p> Signup and view all the answers

<p>Ligand binding to a receptor activates or inhibits the receptor's associated signaling or biochemical pathway, and is regulated by the specificity and number of receptors present on the plasma membrane.</p> Signup and view all the answers

<p>Hormone binding regulates protein synthesis within the cell through special messenger molecules that regulate protein synthesis.</p> Signup and view all the answers

<p>Membrane receptors regulate cellular function by determining which ligands a cell will bind with and how the cell will respond to binding, influencing cellular responses to hormones, neurotransmitters, and other molecules.</p> Signup and view all the answers

<p>Receptor binding to a ligand activates or inhibits the receptor's associated signaling or biochemical pathway, influencing cellular response to hormones, neurotransmitters, and other molecules.</p> Signup and view all the answers

<p>Receptor classification based on location and function helps to understand their specific roles in regulating cellular function and response to external stimuli.</p> Signup and view all the answers

<p>The main purpose of the extracellular matrix is to provide mechanical support, control cell proliferation, form a scaffold for tissue regeneration, and establish tissue microenvironments.</p> Signup and view all the answers

<p>The extracellular matrix is an intricate meshwork of interstitial fibrous proteins, while the basement membrane is a thin, tough, and flexible sheet of matrix molecules that lies beneath epithelial cells.</p> Signup and view all the answers

<p>Cells adhere to each other through cell-to-cell adhesions, facilitated by cell adhesion molecules in the cell's plasma membrane, and are held together by the extracellular matrix and specialized cell junctions.</p> Signup and view all the answers

<p>The primary function of the plasma membrane is to serve as the outer boundary of the cell and allow groups of cells to be held together robustly.</p> Signup and view all the answers

<p>To provide tensile strength or resistance to longitudinal stress.</p> Signup and view all the answers

<p>Cells can lift heavy objects like a textbook by forming muscles, which are robust tissues that are held together by cell-to-cell adhesions and the extracellular matrix.</p> Signup and view all the answers

<p>The extracellular matrix provides a pathway for diffusion of nutrients, wastes, and other water-soluble traffic between the blood and tissue cells, and helps regulate cell growth, movement, and differentiation.</p> Signup and view all the answers

<p>To provide elasticity and allow for stretching and recoiling in tissues such as the lungs.</p> Signup and view all the answers

<p>Cell-to-cell adhesions are crucial for forming tissues and organs, as they allow cells to be held together robustly and enable the formation of robust tissues.</p> Signup and view all the answers

<p>To promote cell adhesion and cell anchorage.</p> Signup and view all the answers

<p>The fibrils that give cartilage its tensile strength are destroyed.</p> Signup and view all the answers

<p>Cells interact with their environment through the extracellular matrix, which provides a pathway for diffusion of nutrients, wastes, and other water-soluble traffic between the blood and tissue cells.</p> Signup and view all the answers

<p>To connect cells together to form tissues and organs.</p> Signup and view all the answers

<p>Specialized cell junctions help hold cells together and facilitate the formation of robust tissues and organs.</p> Signup and view all the answers

<p>To secrete the extracellular matrix.</p> Signup and view all the answers

<p>The main function of the basement membrane is to provide a thin, tough, and flexible sheet of matrix molecules that lies beneath epithelial cells and surrounds individual muscle cells, fat cells, and Schwann cells.</p> Signup and view all the answers

<p>It helps regulate the functions of the cells within which it interacts, including cell growth, movement, and differentiation.</p> Signup and view all the answers

<p>The majority of the tissue is composed of extracellular matrix, with cells scattered within it.</p> Signup and view all the answers

<p>It is a component of the extracellular matrix, along with proteoglycans, collagen, and elastin.</p> Signup and view all the answers

<p>They can be hard and dense, like bone; flexible, like tendons or the dermis of the skin; resilient and shock absorbing, like cartilage; or soft and transparent, like the jelly-like substance that fills the eye.</p> Signup and view all the answers

<p>to regulate cell-ECM interactions with collagen, fibronectin, vitronectin, and fibrinogen</p> Signup and view all the answers

<p>They are Ca++-dependent glycoproteins</p> Signup and view all the answers

<p>to bind certain carbohydrates, for example, mucins</p> Signup and view all the answers

<p>to form a tight seal and hold cells together</p> Signup and view all the answers

<p>to provide a special type of chemical communication, for example, inorganic ions and small water-soluble molecules</p> Signup and view all the answers

<p>asymmetrical junctions</p> Signup and view all the answers

<p>to bind the cell to an adjacent cell and to components of the extracellular matrix (ECM)</p> Signup and view all the answers

<p>symmetrical junctions</p> Signup and view all the answers

<p>to provide strong mechanical attachments</p> Signup and view all the answers

<p>to bind integrins or other IgSF CAMs</p> Signup and view all the answers

<p>They unite cells and maintain structural stability by forming continuous bands or belts of epithelial sheets or developing button-like points of contact.</p> Signup and view all the answers

<p>They act as barriers to diffusion, preventing the movement of substances through transport proteins in the plasma membrane and leakage of small molecules between the plasma membranes of adjacent cells.</p> Signup and view all the answers

<p>They allow small ions and molecules to pass directly from the inside of one cell to the inside of another through communicating tunnels or connexons.</p> Signup and view all the answers

<p>It is a highly permeable part of the plasma membrane formed by the zones between epithelial cells, including the zonula occludens, zonula adherens, and macula adherens.</p> Signup and view all the answers

<p>It causes decreased permeability at the junctional complex.</p> Signup and view all the answers

<p>It travels through the junctional complex and increases calcium levels in neighboring cells, causing damaging effects.</p> Signup and view all the answers

<p>It forms a relatively impermeable wall around the injured area, sealing off the damaged cells.</p> Signup and view all the answers

<p>It is a part of the junctional complex that forms a barrier to diffusion and prevents the leakage of small molecules between adjacent cells.</p> Signup and view all the answers

<p>It is a part of the junctional complex that helps to unite cells and maintain structural stability.</p> Signup and view all the answers

<p>It is a part of the junctional complex that helps to unite cells and maintain structural stability.</p> Signup and view all the answers

<p>To directly coordinate the activities of adjacent cells.</p> Signup and view all the answers

<p>Contact-dependent signaling</p> Signup and view all the answers

<p>Paracrine signaling</p> Signup and view all the answers

<p>Autocrine signaling</p> Signup and view all the answers

<p>Disease onset and progression</p> Signup and view all the answers

<p>To affect the cell itself and other cells in direct physical contact</p> Signup and view all the answers

<p>Gap junctions</p> Signup and view all the answers

<p>Compromised normal growth control and cell differentiation, favoring cancerous tumor development</p> Signup and view all the answers

<p>Hormonal signaling</p> Signup and view all the answers

<p>Contact-dependent, paracrine, hormonal, neurohormonal, and neurotransmitter signaling</p> Signup and view all the answers

<p>Hormones are released by endocrine cells and travel through the bloodstream to produce a response in other sets of cells.</p> Signup and view all the answers

<p>Neurohormonal signaling involves the release of blood-borne chemical messengers, whereas ordinary neuronal signaling involves the release of short-range neurotransmitters at synapses.</p> Signup and view all the answers

<p>Signal transduction pathways transmit signals from the cell surface to the cell interior, amplifying and distributing the signal to multiple targets.</p> Signup and view all the answers

<p>Cells undergo programmed cell death, or apoptosis.</p> Signup and view all the answers

<p>Signal transduction pathways amplify the signal through a multiplying effect, where one ligand molecule can activate multiple downstream targets.</p> Signup and view all the answers

<p>Plasma membrane receptors recognize and respond specifically to extracellular signal molecules.</p> Signup and view all the answers

<p>The signal can either open or close specific channels in the membrane, or transfer the signal to an intracellular messenger.</p> Signup and view all the answers

<p>Signal transduction pathways allow cells to respond to their environment, influencing processes such as cell growth, survival, and differentiation.</p> Signup and view all the answers

<p>Protein kinases activate a path of intracellular signaling molecules, leading to cellular responses such as growth, survival, or differentiation.</p> Signup and view all the answers

<p>Hormones are chemical messengers that allow cells to communicate with each other.</p> Signup and view all the answers