Chapters 4-5 Flashcards
light microscope
can display living cells
resolution
- ability to distinguish two nearby objects as separate
- measure of the clarity of an image
cell theory
states that
- all living things are composed of cells
- all cells come from other cells
electron microscope
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?
geometry.
- need to have a surface area large enough to service the volume of a cell
plasma/cell membrane
- forms a flexible boundary between the living cell and its surroundings
- a phospholipid bilayer with embedded proteins.
prokaryotic cells
- first to evolve
- earth’s sole inhabitants
- bacteria and archaea
eukaryotic cells
evolved from ancestral cells about 1.8 billion years ago
-everything else
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
cytosol
a thick, jelly-like fluid in the interior of all cells
chromosomes
carry genes made of DNA
ribosomes
- are composed of ribosomal RNA and proteins
- synthesize proteins according to directions from DNA.
cytoplasm
-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
- chloroplast
nucleus
contains the cell’s genetic instructions encoded in DNA
nucleolus
site in the nucleus where ribosomal RNA is synthesized according to instructions in the DNA
magnification
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
- nucleus and ribosomes carry out the genetic control of the cell.
- Organelles involved in the manufacture, distribution, and breakdown of molecules include the endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and peroxisomes.
- Mitochondria in all cells and chloroplasts in plant cells function in energy processing.
- Structural support, movement, and communication between cells are the functions of the cytoskeleton, plasma membrane, and plant cell wall.
the ER
is a membranous network of tubes and sacs.
smooth ER
synthesizes lipids and processes toxins.
rough ER
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.
lysosomes
house enzymes that break down ingested substances and damaged organelles.
vacuoles
are large vesicles that have a variety of functions.
-Some protists have contractile vacuoles.