Ch 3 and 4 Flashcards
What is a cell?
the smallest unit that can live on its own and that makes up all living organisms and the tissues of the body
Know the three basic parts of a cell. (nucleus, plasma membrane, cytoplasm)
• Nucleus: controls and regulates the activities of the cell (e.g., growth and metabolism) and carries the genes, structures that contain the hereditary information.
• Plasma membrane: consists of a lipid bilayer that is semipermeable, it regulates the transport of materials entering and exiting the cell
• Cytoplasm: the gelatinous liquid that fills the inside of a cell. It is composed of water, salts, and various organic molecules.
Know the structure of the plasma membrane and the lipid bilayer
The plasma membrane: Lipid bilayer and proteins in constantly changing fluid mosaic, Separates intracellular fluid (ICF) from extracellular fluid (ECF). The lipid bilayer has lipid tails that are hydrophilic and lipid tails that are hydrophobic
Define hydrophilic and hydrophobic.
Hydrophilic: water loving
Hydrophobic: water fearing
What are the functions of the nucleus?
• Control of metabolism
• storage and processing of genetic information
• control of protein synthesis
Know the 6 functions of membrane proteins
- Transport
- Receptors for signal transduction
- Attachment to cytoskeleton and extracellular matrix
- Enzymatic activity
- Intercellular joining
- Cell-cell recognition
What is meant by “selectively permeable” membrane
• Allows some materials to move freely. Restricts other materials
• Restricts materials based on Size, Electrical charge, Molecular shape, Lipid solubility.
Describe autolysis and the role of the lysosome
Self-destruction of damaged cells
• Lysosome membranes break down
• Digestive enzymes released
• Cell decomposes
• Cellular materials recycle
Understand passive vs. active transport.
• Active (requiring energy and ATP)
• Passive (no energy required)
Know the 3 types of diffusion (simple, facilitated, and osmosis) and understand filtration
• Simple diffusion: he movement of individual molecules of a substance through a semipermeable barrier from an area of higher concentration to an area of lower concentration. ( Fatty acids, alcohols, steroids, oxygen and carbon dioxide.
• Facilitated Diffusion: molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers
• Osmosis: is the diffusion of water across the cell membrane
• Filtration: the process in which solid particles in a liquid or gaseous fluid are removed by the use of a filter medium that permits the fluid to pass through but retains the solid particles
Understand how molecules move up or down a concentration gradient
Through osmosis, active transport and passive transport.
Know how osmosis works and its importance.
• More solute molecules, lower concentration of water molecules
• Membrane must be freely permeable to water, selectively permeable to solutes
• Water molecules diffuse across membrane toward solution with more solutes
• Volume increases on the side with more solutes
Define isotonic, hypertonic, and hypotonic and how these solutions affect cells.
Isotonic: A solution that does not cause osmotic flow of water in or out of a cell ( cells remains the same)
Hypertonic: Has more solutes and gains water by osmosis ( cells loses water and shrivels up/shrinks)
Hypotonic: Has less solutes and loses water through osmosis ( cells gains water and expands)
Describe primary active transport. Provide an example
Primary active transport: Sodium–potassium exchange pump
• Active transport, carrier mediated
• Sodium ions (Na+) out, potassium ions (K+) in
• 1 ATP moves 3 Na+ and 2 K
Define exocytosis and endocytosis
• Exocytosis: Granules or droplets are released from the cell
• Endocytosis: the taking in of matter by a living cell by invagination of its membrane to form a vacuole.
