AP BIO Unit 2

• What components do all living cells contain?

  A genome and ribosomes
• Why do organisms need mechanisms to store and pass down genetic information?

  To ensure the continuity of genetic information and nucleic acids
• What is the function of ribosomes in a cell?

  They synthesize proteins according to mRNA sequences
• What structure encloses the genome of eukaryotic cells?

  The nucleus
• Are ribosomes membrane-enclosed structures?

  No, ribosomes are not membrane-enclosed structures
• What are the two subunits of ribosomes made of?

  RNA (rRNA) and proteins
• What is the role of the endoplasmic reticulum (ER) in eukaryotic cells?

  It has additional membrane-enclosed organelles that perform specialized functions
• What are the functions of the rough and smooth endoplasmic reticulum (ER)?

  • Rough ER:
  • Has ribosomes attached
  • Packages newly synthesized proteins for export
  • Provides mechanical support
  • Plays a role in intracellular transport
  • Smooth ER:
  • Lacks ribosomes
  • Functions in detoxification and lipid synthesis
• What is the Golgi apparatus composed of?

  A series of flattened membrane-bound sacs
• What is the primary function of the Golgi apparatus?

  It modifies, folds, and packages newly synthesized proteins for trafficking
• What type of membrane do mitochondria have?

  A double membrane
• What is the function of the cristae in mitochondria?

  They increase the surface area for ATP production
• What do lysosomes contain?

  Hydrolytic enzymes
• What are the functions of lysosomes?

  • Intracellular digestion
  • Recycling organic materials
  • Programmed cell death (apoptosis)
• What are vacuoles in eukaryotic cells used for?

  Storage of water and other macromolecules
• What role do large central vacuoles play in plant cells?

  They aid in the retention of water for turgor pressure
• What is the primary function of chloroplasts?

  To capture energy from the sun and produce sugar
• What are thylakoids in chloroplasts?

  Highly folded membrane compartments where light-dependent reactions occur
• How do the rough ER, vesicles, and Golgi apparatus work together?

  They synthesize and isolate proteins for secretion or use in the cell
• What happens to the surface area to volume ratio as cells increase in size?

  The relative surface area decreases
• What is the formula for the surface area of a cube?

  Surface Area = 6s^2
• What is the formula for the volume of a cube?

  Volume = s^3
• Why do smaller cells transport materials more efficiently?

  They have a higher surface area to volume ratio
• What is the role of root hairs in plants?

  They increase the surface area for absorption of water and nutrients
• How do the villi and microvilli in the small intestine aid in nutrient absorption?

  They increase the surface area for absorption
• What is the function of stomata in plants?

  They allow for the exchange of gases with the environment
• What is the cell membrane?

  A thin flexible barrier that surrounds every cell
• What are phospholipids?

  Molecules that are amphipathic, with hydrophilic heads and hydrophobic tails
• How do phospholipids arrange themselves in an aqueous environment?

  They form a bilayer with tails inside and heads exposed to water
• What are the two types of embedded proteins in the cell membrane?

  • Peripheral proteins:
  • Loosely bound to the membrane surface
  • Hydrophilic with charged and polar side groups
  • Integral proteins:
  • Span the membrane
  • Hydrophilic ends and hydrophobic middle
• What is the fluid mosaic model of the cell membrane?

  It describes the membrane as a mosaic of proteins in a fluid bilayer of phospholipids
• What is the role of cholesterol in the cell membrane?

  It regulates bilayer fluidity under different environmental conditions
• What are glycoproteins and glycolipids?

  Glycoproteins have carbohydrates attached to proteins; glycolipids have carbohydrates attached to lipids
• What is a concentration gradient?

  It occurs when a solute is more concentrated in one area than another
• What is passive transport?

  Net movement of molecules from high concentration to low without metabolic energy
• What are the two types of passive transport?

  • Diffusion: Movement of small nonpolar molecules to low concentration
  • Facilitated diffusion: Movement through transport proteins for hydrophilic molecules and ions
• What is the purpose of transport proteins?

  To help hydrophilic substances move across the membrane
• What is the function of a cell wall in plant cells?

  It protects and maintains the shape of the cell
• What are plasmodesmata?

  Small holes between plant cells that allow transfer of nutrients, waste, and ions
• What are cell walls composed of in plants?

  Cellulose