3.2-3.3 Eukaryotic Cells Flashcards
what is an eukaryotic cell
presence of nucleus + organelles surrounded by mebrane
animals, plants,fungi, protists
plasma (cell) membrane
-c: phospholipid bilayer embedded w protein molecules
-f: living boundary that separates living contents of cell from surrounding environment
regulates entrance/exit of molecules into and out of cell
cytoplasm
c: water, salts, dissolved organic molecules
f: semi fluid medium inside of cell
cell walls
PLANT CELLS ONLY
c: primary cell wall composed of cellulose that forms firbils that lie right angle to each other for added strength
secondary cell wall composed of lignin, stronger than primary cell wall
fungi cell wall composed of chitin and cellulose
algae (protista fam) cell walls composed of chitin
define organelle
originally only referred to membraneous structures, now means any well defined subcellular structure that performs a particular function
nucleus
c: nuclear envelope, nucleoplasm, chromatin, nucleoli
f: stores genetic information, synthesis of DNA and RNA
what is chromatin (chromosomes, nucleoplasm)
- consists of DNA associated w proteins
- in cells lifetime, chromatin present but when cell ready to undergo cell division, it will undergo coiling and become chromosomes (highly condensed structures) immersed in semifluid medium NUCLEOPLASM
- humans have 46 chromosomes
what does a difference in pH between the necleoplasm and cytoplasm suggest
nucleoplasm has a diff composition
nucleolus (nucleoli plu)
c: concentrated area of chromatin, RNA, proteins
f: forms rRNA (ribosomal RNA) that joins w proteins to form subunits of ribosomes
what is a nuclear envelope
double membrane that separates nucleus from cytoplasm, which is continuous to endoplasmic reticulum
what are nuclear pores
pores of 100nm that permit the directional transport of proteins and ribosomal subunits
-can control events within nucleus or entire cell
what happens in the nucleus during cell division
- nuclear envelope completely disappears
- contents of nucleus completely mixed w cytoplasm
- following cell division, nuclear envelope re-forms around chromosomes and other contents of nucleus transported into nucleus
ribosomes
c: protein and RNA in two subunits “large” and “small”
f: protein synthesis, found in cytoplasm, or attached to ER
what are the components of the endomembrane system
nuclear envelope, endoplasmic reticulum, golgi apparatus, vesicles
vesicles
c: membranous sacs of various sizes
f: storage of substances
endoplasmic reticulum
c: complicated system of membranous channels and sacs, continuous w outer membrane of nuclear envelope
f: synthesis,modification of proteins and other substances, distribution by vesicle formation
rough ER
c: network of folded membranes studded w ribosomes on side that faces cytoplasm
f: as proteins are synthesized on these ribosomes that pass into ER, where processing and modification begin (proteins synthesized here either exocytosis or endocytosis)
-folding, modification, processing, transport of proteins
EX) cystic fibrosis: mutated plasma membrane channel protein remains in ER bc folded incorrectly, cell not in correct place unable to regulate transport of chlroide ions = various symptoms of diseases
smooth ER
c: network of folded membranes having no ribosomes continuous w rough ER
f: -synthesizes phospholipids found in cell membranes
- forms vesicles which products are transports to Golgi apparatus
- in testes produces testosterone
- in liver detoxifies drugs
- in muscle cells stores calcium ions
Golgi apparatus (body)
c: stack of 3-20 slightly curved membraneous sacs
f: collects, sorts, packages, distributes materials like proteins and lipids
-formation of lysosomes
-one side of stack (inner face) directed towards ER
-other side (outer face) directed towards plasma membrane
vesicles can frequently be seen at the edges of sacs
what is the process of secretion
- golgi body receives proteins and lipid filled vesivles from ER
- molecules move through golgi from inner face to outer face, during passage, proteins, lipids, modified before repackaged into secretory vesicles
- secretory vesicles proceed to plasma membrane where secreted
lysosomes
ANIMAL CELL
c: membrane vesicle containing hydrolytic digestive enzymes
f: intracellular digestion; macromolecules brought into cell by vesicle formation at plasma membrane, when lysosome fuses w vesicle, its contents are digested by lysosomal enzymes into simpler subunits that enter cytoplasm
vacuole
c: large membranous sacs, larger than vesicle, plants have larger vacuole filled w watery fluid that provides additional support to cell
f: stores substances, plant vacuoles store water, sugars, salts, pigments, toxic molecules
(pigments for colour, toxic molecules that protect plant from herbivorous animals)
peroxisomes
c: membranous vesicle containing specific enzymes that are synthesized by cytoplasmic ribosomes and transported to peroxisome by carrier proteins
f: metabolic tasks
-cells that synthesis and break down fats
liver it break down fats and produce bile salts from chloestrol
-plant cells: oxidize fatty scids into molecules that can be converted to sugars needed by the growing plant
-leaves: carry rxn opp. to photosynthesis, use O2, releases CO2
RH2 + O2 -> R + H2O2 contain enzyme that action result in hydrogen peroxide
which organelles specialize in converting energy to a form cells can use
chloroplasts and mitochondria
chloroplasts
PRIMARILY PLANT CELLS
c: membranous grana bounded by two membranes in a fluid filled space called the stroma which contains a single ciruclar DNA molecule as well as a ribosome
- contains own genetic matieral makes own proteins
f: photosynthesis (solar energy +CO2 +H2O -> CARB +O2)
- membrane system in stroma organized into interconnected flattened sacs (thylakoids) stacked up to structures in granna (can be hundreds)
- chlorophyll (located in thylakoid membrane of grana) capture solar energy needed to enable chloroplasts to produce carbohydrates just read pg 76
mitochondria
c: inner membrane (cristae) bounded an outer membrane
f: cellular respiration
what is the matrix and cristae
matrix: inner fluid filled space in mitochondria. contains ribosomes and enzymes that break down carbohydrate products and release energy used for ATP production
cristae: inner membrane of mitochondrion folded inwards on itself, provides more surface area to accomodate protein complexes and other participants that produce ATP
cytoskeleton
protein components of cytoskeleton interconnect and extend from nucleus to plasma membrane
c: contains actin filaments, intermediate filaments, and microtubules which maintain cell shape and allow cell and organelles to move
f: shape of cell and movements of part
what are actin filaments
long, extremely thin, flexible fibres that occur in bundles of meshlike networks
- each contain 2 chains of globular actin monomers twisted about one another in a helical manner
- complex web under plasma membrane anchored by special proteins
- in microvilli that project from intestinal cells
what are motor molecules
proteins that can attach, detach, and reattach farther along the actin filament
-to produce movements, actin filaments ineract w motor molecules
what are intermediate filaments
- perform structural role in cell
- rope like assembly of fibrous polypeptides
- inermediate size between actin filaments and microtubules
what are microtubules
small, hollow cylinders 25nm long, 0.2 - 25 microm long
- made up of globular protein tubulin (2 types: alpha and beta)
- 13 rows of tubulin dimers surrounding an empty core
what is a centrosome
main microtubule organizing centre lies near nucleus
- microtubules radiate from centrosome maintaining shape of cell and acting as tracks which organelles can move
- before a cell divides, microtubules disassemble and reassemble into spindle that attaches to chromosome and ensures that they are distributed evenly, at the end of cell division spindle disassembles and microtubules reassemble to form former array
centriole
c: short cylinders of microtubules with 9 sets of 3 + 0 pattern of microtubules,
f: formation of basal bodies, replicate so that members of each pair are right angle to one another. then, each pair becomes part of separate centrosome
cilia and flagella
c: 9 + 2 pattern of microtubules
f: movement of cells
