56 Questions
What defines both blood type and tissue type according to the text?
The specific structures on the glycocalyx
What are the identifying proteins carried by each person's white blood cells?
Human leukocyte antigens (HLAs)
What type of proteins penetrate the hydrophobic core of the lipid bilayer?
Integral proteins
What is used to match tissues before organ transplants?
HLA
What forms a layer on the cell membrane called the glycocalyx?
Glycoproteins and glycolipids
What are appendages loosely bound to the surface of the bilayer membrane?
Peripheral proteins
What type of proteins completely span the membrane?
Transmembrane proteins
What is unique and defines cells as belonging to a specific organism?
Glycocalyx
What is the main component of the plasma membrane?
Phospholipid bilayer
How are phospholipid molecules arranged in the cell membrane?
In a double layer (bilayer)
What are glycoproteins and glycolipids?
Proteins and lipids with sugars attached to their external surface
What does it mean for the plasma membrane to be selectively permeable?
It chooses what may cross the membrane
What is the function of the plasma membrane in chemical reactions?
Participate in chemical reactions
Which component is interspersed with phospholipids in the cell membrane?
Proteins
What is the external surface of glycoproteins and glycolipids attached with?
Sugars
What orients toward the aqueous environment both inside and outside the cell in the phospholipid bilayer?
Hydrophilic, water-loving, polar heads
What is the main component of the plasma membrane?
Phospholipid bilayer
What is the orientation of the hydrophilic heads of phospholipid molecules in the bilayer?
Toward the aqueous environment inside and outside the cell
What are glycoproteins and glycolipids?
Proteins and lipids with sugars attached to their external surface
What does it mean for the plasma membrane to be selectively permeable?
It chooses what may cross the membrane
What is the function of the plasma membrane in chemical reactions?
Participate in chemical reactions
What is the role of cholesterol in the cell membrane?
Regulate membrane fluidity and stability
What contributes to the fluid mosaic nature of the plasma membrane?
Lipids and proteins
What is the arrangement of phospholipids in the cell membrane?
Double layer or bilayer
What forms a layer on the cell membrane called the glycocalyx?
Glycoproteins and glycolipids
What is used to match tissues before organ transplants?
Human leukocyte antigens (HLAs)
What type of proteins penetrate the hydrophobic core of the lipid bilayer?
Integral proteins
What are the identifying proteins carried by each person's white blood cells?
Human leukocyte antigens (HLAs)
What is the fluid bilayer of phospholipid molecules with a 'mosaic' pattern of various proteins embedded in it called?
Fluid mosaic structure
What is unique and defines cells as belonging to a specific organism?
Glycocalyx
What type of proteins are appendages loosely bound to the surface of the bilayer membrane?
Peripheral proteins
What serves as markers indicating that our cells belong to us?
Human leukocyte antigens (HLAs)
Which type of transport involves the passive movement of molecules along their concentration gradient, guided by the presence of another molecule?
Facilitated Diffusion
In which type of transport are molecules or ions transported across the membrane against their concentration gradients?
Active Transport
Which process involves the almost complete uptake of digested nutrients from the small intestine?
Active Transport
What occurs when extracellular molecules and particles are taken into the cell via vesicle formation?
Endocytosis
Which type of cell signaling involves circulating hormones reaching every cell through the bloodstream?
Endocrine signaling
In which type of signaling do cells communicate with one another via chemical messengers or through physical contact?
Juxtacrine signaling
What type of junctions are used for instantaneous communication across very short distances and are extremely specific?
Gap junctions
Which type of junctions occur in tissues like the skin and heart muscle tissue, where cells are in direct contact with one another?
Tight junctions
What type of communication do neurons use to stimulate nearby nerve, muscle, or glandular cells by releasing short-lived chemicals called neurotransmitters?
Neuronal signaling
Which type of communication is mostly used when quick responses are required?
Paracrine signaling
In which type of transport are molecules or ions transported across the membrane against their concentration gradients?
Active Transport
Which type of transport involves the passive movement of molecules along their concentration gradient, guided by the presence of another molecule?
Facilitated Diffusion
What is the movement of a substance toward the area of its lower concentration called?
Diffusion
What is the term for the diffusion of water across a semipermeable membrane?
Osmosis
What occurs when extracellular fluid is isotonic to the cells?
Water flows equally into and out of the cell
What may cause a cell to swell and burst?
Hypotonic solution
What may cause a cell to shrink and shrivel up?
Hypertonic solution
Which type of transport does not require the cell to expend energy to move molecules across membranes down their concentration gradients?
Passive transport
Which type of molecules move easily through the membrane, such as O2, CO2, and H2O?
Large hydrophobic molecules
What is the term for the movement of a substance toward the area of its lower concentration?
Diffusion
Which type of solution has water with a lower concentration of solutes than the cytosol?
Hypotonic solution
Which type of solution has water with a higher concentration of solutes than the cytosol?
Hypertonic solution
What is the term for the movement of a substance toward the area of its lower concentration?
Diffusion
What is the term for the diffusion of water across a semipermeable membrane?
Osmosis
Study Notes
Blood Types and Tissue Matching
- Blood type and tissue type are defined by specific identifying proteins on each person's white blood cells.
- Matching tissues before organ transplants is done using these identifying proteins to ensure compatibility.
Cell Membrane Structure
- The plasma membrane is primarily composed of phospholipids, arranged in a bilayer.
- Phospholipid molecules have hydrophilic heads oriented towards the aqueous environment inside and outside the cell.
- The hydrophobic tails face inward, forming a barrier to most water-soluble substances.
- Cholesterol is interspersed among the phospholipids, providing stability and fluidity.
Glycocalyx and Membrane Components
- The glycocalyx is a layer formed on the cell membrane, consisting of glycoproteins and glycolipids.
- Glycoproteins and glycolipids have external surfaces that interact with the cell's environment and serve as recognition sites.
- Appendages loosely bound to the surface of the bilayer are known as peripheral proteins.
Protein Classification in the Membrane
- Integral proteins penetrate the hydrophobic core of the lipid bilayer, completely spanning the membrane.
- Markers indicating that cells belong to a specific organism include glycoproteins and glycolipids.
Membrane Permeability and Transport
- The selectively permeable plasma membrane allows some substances to pass while restricting others.
- Passive transport involves movement of molecules along their concentration gradient without energy expenditure.
- Facilitated diffusion is a type of passive transport aided by the presence of another molecule.
- Active transport requires energy to move molecules against their concentration gradients.
Cellular Communication
- Hormonal signaling involves circulating hormones reaching every cell via the bloodstream.
- Paracrine signaling allows cells to communicate with each other via chemical messengers or direct contact.
- Gap junctions enable instantaneous communication across short distances in tissues.
- Tight junctions occur where cells in tissues like skin and heart muscle are in close contact.
Osmosis and Diffusion
- Osmosis is the diffusion of water across a semipermeable membrane.
- Isotonic conditions occur when extracellular fluid has equal solute concentration to the cytosol, maintaining cell shape.
- Hypotonic solutions, with lower solute concentration than the cytosol, may cause cells to swell or burst.
- Hypertonic solutions, with higher solute concentration, can cause cells to shrink and shrivel.
General Membrane Functions
- The plasma membrane participates in chemical reactions, facilitating exchanges and interactions.
- Molecules like O2, CO2, and H2O move easily through the membrane due to their small size and nonpolar nature.
- The process of diffusion guides substances towards areas of lower concentration, promoting equilibrium.
Test your knowledge of the movement of substances across cell membranes with this quiz. Explore the concepts of passive and active transport, as well as the types of molecules that can easily move through membranes. Discover how cells regulate the entry of nutrients and the exit of waste products.
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