Chapter 5 Flashcards
cell theory
all organisms are composed of cells
cell is basic structural and fundamental unit of all living organisms
cells arise only from the division of preexisting cells
resolution
minimum distance two points in the spectrum can be separated and still be seen as two points
plasma membrane
bilayer made of lipids with imbedded protein molecules
cytoplasm
all the parts of the cell between the plasma membrane and the central region
organelles
small organized structures important for cell function
cytosol
aqueous solution containing ions and various organic molecules
cytoskeleton
protein based framework of filamentous structures that help maintain proper cell shape and plays a key role in cell division
prokarytoes
dna is not separated from rest of cell
nucleoid
dna containing region for prokaryotes
eukaryotes
dna is separate from rest of cell
nucleus
dna containing region for eukaryotes
prokaryotic chromosome
single circular molecule that unfolds when released from the cell
prokaryotic cells
o Prokaryotic chromosome- single circular molecule that unfolds when released from the cell
o Ribosomes- small spherical particles in the cytoplasm that use info in mRNA to assemble amino acids into proteins
o Cell Wall- rigid external layer of material
o Glycocalyx- layer of polysaccharides that coat cell wall
Slime Layer- when loosely associated with the cells
Capsule- more firmly attached to cells
o Flagella- long thread-like protein fibers that move cell
o Bacterial flagella- helically shaped that rotate to move cell
o Pili- hair like shafts of protein
nuclear envelope
two membranes that separate the cytoplasm from the nucleus; reinformed by lamins
nuclear pore complex
large cylindrical structure formed of many proteins(nucleoporins) that exchange components between nucleus and cytoplasm
nuclear location signal
short amino acid sequence that distinguishes between proteins that need to be imported into the nucleus from those in the cytoplasm
nucleoplasm
liquid substance within nucleus
chromatin
combination of dna and proteins
nucleoli
irregular masses of small fibers and granules where rRNA genes become rRNA molecules
vesicles
small membrane bound compartments that transfer substances between parts of the system
endoplasmic reticulum
interconnected network of membrane channels and vesicles called cisternae
er lumen
enclosed space in endoplasmic reticulum
rough er
has ribosomes on outsides; proteins are folded into final form
smooth er
no ribosomes; synthesis of lipids that become part of cell membrane
golgi complex
stacks of flattened membraneous sacs known as cisternae
no ribosomes
cis-where proteins are modified
trans-sorted into veiscles that bud off
regulates movement of proteins
secretory vesicles- transport proteins to plasma membrane
exocytosis-when the vesicles release the proteins
endocytic vesicle-carry susbtances from plasma membrane to rest of cell
lysosomes
small membrane bound vesicles that are for the digestion of complex molecules
only in animals
formed by budding form golgi complex
enzymes made in rough er
acidic
phagocytosis-process where some cells enfulf bacteria or other debris to break them down
mitochondria
where cellular respiration occurs
require oxygen
outer mitochondrial membrane-smooth and covers the outside of the organelle
inner mitochondrial membrane- expanded by folds called cristae
mitochondrial matrix-innermost compartment of mitochondria
atp generating reaction occur in cristae and matrix
microbodies
small organelles found in various form in all eukarytoic cells
proteins and phosphoiipids are constantly transported into them
contain enzymes that conduct intermediate reactions linking major pathways
peroxisomes- microbodies that produce hydrogen peroxide
in plants convert oils or fats to sugars
cytoskeleton-microtubules
- Alpha tubulin and beta tubulin noncovalently bonded together
- Change length to fit function
- Cell center/centrosome- site near nucleus where microtubules radiate from
- Centrioles- short, barrel shaped structure at midpoint
- Provide anchor for some organelles and tracts for some vesicles
cytoskeleton-intermediate filaments
only found in multicellular organisms
provide strucutral support
cytoskeleton-microfilaments
structural and locomotor functions
actively flowing motion of cytoplasm
flagella
basal body-structure that anchors flagella and cilia to surface of cell
three types
plant cells-chloroplasts
Collectively known as plastids
Amyloplasts- colorless plastids that store starch
Chromoplasts- responsible for colors of ripening fruits and autumn leaves
Have an outer and inner boundary membrane
Grana- thylakoids stacked on top of each other
Stoma- inner compartment
plant cells-central vaculoues
pressure from it supports the cell
tonoplast-membrane that surrounds central vacuole
produce color of flowers
plant cells-cell walls
support and mantain pressure in cell
primary cell wall-soft and flexible
secondary cell wall-more rigid and thicker;reiforced with lingin
middle lamella-gel like polysaccarides that hold adjacent cells together
plasmodesmata-minute channels between two walls
animal cells-cell adhesion
bind cells together; helps maintain body form and structure; bind to specific molecules on other cells
connections are eventually made permanent by cell junction
animal cells-cell junctions
seals spaces between cells and provides communication between them
anchoring junctions-weld adjacent cells together
desosomes-intermediate filaments anchor the junction in the underlying cytoplasm
adherens junctions-uses microfilaments
Tight junctions- regions of tight connections
• Formed by direct fusion of proteins on outer surfaces of membranes of adjacent cells
Gap junctions- open direct channels to allow ions and small molecules to pass from one cell to another
extracellular matrix
provides cells and provides mechanical linkage
