chapter 3

Cards (75)

  • Cells are the smallest unit of life that can function independently
  • Being composed of cells is one of the most basic characteristics of life
  • All organisms are made of one or more cells
  • The cell is the fundamental unit of life
  • All cells come from preexisting cells
  • All cells have the same basic chemical composition
  • All cells use energy
  • All cells contain DNA that is duplicated and passed on as each cell divides
  • Light microscopes are used to view the entire cell
  • Electron microscopes are used to view the parts of cells, and viruses, which are smaller and require higher magnification
  • A transmission electron microscope (TEM) is a very powerful tool for seeing internal cell structures
  • A scanning electron microscope (SEM) is also very powerful and reveals details on cell surfaces
  • All cells have genetic material, ribosomes, cytoplasm, and a cell membrane
  • Prokaryotes are small, simple in structure, and lack a nucleus
  • Bacteria and archaea are two different domains of prokaryotes
  • Eukaryotes are larger and more complex, with many internal parts including a nucleus and other membranous organelles
  • Protists, fungi, plants, and animals are eukaryotic
  • Some features are common to all three domains (cell membrane), while others are unique to each domain
  • Bacteria lack membrane-bounded organelles, with ribosomes and DNA free in the cytoplasm
  • Plant cells have most of the same membrane-bounded organelles as animal cells, with additional structures like a large central vacuole, cell wall, and chloroplasts
  • Cell membranes form a barrier between the cell and the outside world, regulating passage of substances and maintaining homeostasis
  • Cell membranes are composed of phospholipids, which are amphipathic molecules with polar and nonpolar regions
  • Phospholipids are made of a molecule of glycerol, a phosphate group, and 2 fatty acids
  • Phospholipids spontaneously form bilayers in water, creating a selectively permeable membrane to lipids and small, nonpolar molecules
  • Phospholipids make up the cell membrane
  • The nucleus controls protein production
  • Proteins are synthesized on ribosomes
  • Lysosomes contain digestive enzymes
  • The cytoskeleton has three major components: Actin molecules microfilaments, intermediate filaments, and microtubules
  • Plant cells are surrounded by a cell wall
  • Plant cells communicate through plasmodesmata
  • Different membrane proteins carry out different functions
  • Cell membranes are fluid mosaics
  • The membrane is neither a solid nor a liquid; it is more like Jell-O
  • The combination of phospholipids and proteins forms a fluid mosaic
  • The nucleus controls protein production
  • The nucleus contains DNA, which specifies the “recipe” for the proteins
  • The nucleus also contains the nucleolus, which synthesizes ribosomes
  • RNA moves from the nucleus out to a ribosome, where the protein is synthesized
  • Proteins are synthesized on ribosomes