Flashcards in Chapters 4-5 Deck (69)
can display living cells
-ability to distinguish two nearby objects as separate
-measure of the clarity of an image
-all living things are composed of cells
-all cells come from other cells
focuses a beam of electrons through a specimen or onto its surface
-can distinguish biological structures
scanning electron microscope
-used to study the detailed architecture of cell surfaces
-uses an electron beam to scan the surface of a cell or other sample.
transmission electron microscope
-used to study details of internal structure
-aims an electron beam through a very thin section of a specimen
what is the maximum size of a cell influenced by?
-need to have a surface area large enough to service the volume of a cell
-forms a flexible boundary between the living cell and its surroundings
-a phospholipid bilayer with embedded proteins.
-first to evolve
-earth's sole inhabitants
-bacteria and archaea
evolved from ancestral cells about 1.8 billion years ago
how are eukaryotic cells distinguished from prokaryotic cells?
-have a membrane-enclosed nucleus
-larger and more complex
-many membrane-enclosed organelles that perform specific functions.
basic features of cells
-have cytosol, chromosomes, ribosomes, cytoplasm
a thick, jelly-like fluid in the interior of all cells
carry genes made of DNA
-are composed of ribosomal RNA and proteins
-synthesize proteins according to directions from DNA.
-in eukaryotic cells, term refers only to the region between the nucleus and the plasma membrane
plant cell structures that animal cells lack
-rigid, rather thick cell wall
contains the cell's genetic instructions encoded in DNA
site in the nucleus where ribosomal RNA is synthesized according to instructions in the DNA
is the increase in an object’s image size compared with its actual size.
four basic groups of organelles and other structures of eukaryotic cells
1. nucleus and ribosomes carry out the genetic control of the cell.
2. Organelles involved in the manufacture, distribution, and breakdown of molecules include the endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and peroxisomes.
3. Mitochondria in all cells and chloroplasts in plant cells function in energy processing.
4. Structural support, movement, and communication between cells are the functions of the cytoskeleton, plasma membrane, and plant cell wall.
is a membranous network of tubes and sacs.
synthesizes lipids and processes toxins.
produces membranes, and ribosomes on its surface make membrane and secretory proteins.
the Golgi apparatus
consists of stacks of sacs in which products of the ER are processed and then sent to other organelles or to the cell surface.
house enzymes that break down ingested substances and damaged organelles.
are large vesicles that have a variety of functions.
-Some protists have contractile vacuoles.
vacuole in plant cells that stores molecules and wastes and facilitates growth.
are metabolic compartments that do not originate from the endomembrane system.