the cell part 2 eukaryotic cells Flashcards
what are eukaryotic organisms
protozoans, algae, fungi, plants, animals
what are eukaryotic cells characterized by
the presence of membrane bound organelles in the cytoplasm
what does the cytoskeleton hold in place
mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes
what is the cytoskeleton
internal network that supports transport of intracellular components and helps maintain cell shape
how is the genome of eukaryotic cells packaging different from eukaryotic cells
it is in multiple rod shaped chromosomes instead of a single circular chromosome
describe the genome characteristics of bacteria
single chromosome
circular
haploid lacks histones
describe genome characteristics of archaea
single chromosome
circular
haploid
contains histones
describe the genome characteristics of eukaryotes
multiple chromosomes,
linear
haploid or diploid
contains histones
how does bacteria divide cells
binary fission
how does archaea divide cells
binary fission
how do eukaryotes divide cells
mitosis, meiosis
membrane lipid composition of bacteria
ester-linked
straight chain fatty acids
bilayer
membrane lipid composition of archaea
ether-linked
branched isoprenoids
bilayer or monolayer
membrane composition of eukaryotes
ester-linked
straight chain fatty acids
sterols
bilayer
cell wall composition of bacteria
peptidoglycan or none
cell wall composition of archaea
pseudopeptidoglycan or
glycopeptide or
polysaccharide or
protein
or none
cell wall composition of eukaryotes
Cellulose (plants, some algae)
Chitin (fungi)
silica (some algae)
most other lack cell walls
motility structure of bactera
rigid spiral flagella composed of flagellin
motility structure of archaea
rigid spiral flagella composed of archaean flagellins
motility structures of eukaryote cells
flexible flagella and cilia composed of microtubules
ribosomes in bacteria and archaea
70s
ribosomes in eukaryotes
80S in cytoplasm and rough ER
70S in mitochondria and chloroplasts
what influences shape a eukaryotic cells
primary function
organization of cytoskeleton
viscosity of cytoplasm
rigidity of cell membrane
physical pressure exerted on it
how is dna in a eukaryotic cell organized
condensed to fit in the nucleus and wrapped around histones
how are some protozoan nuclei different
they have to complete nuclei
one for reproduction and a larger one for cellular metabolism
what are heterokaryotic cells
cells in some fungi that are transiently formed with two nuclei
why are coenocytes
cells whose nuclei divide but the cytoplasm does not
what is the nucleus bound to
the nuclear membrane
what does the nuclear membrane consist of
two distinct lipid bilayers that are contiguous with each other
what does the nuclear membrane contain
nuclear pores that control the movement of materials into and out of the cell
describe nuclear pores
large, rosette-shaped protein complexes
what determines the shape of the nucleus
the nuclear lamina
what is the nuclear lamina
a meshwork of intermediate filaments found just inside the nuclear envelope membranes
what happens in interphase
the cell grows and DNA is replicated
what are the 3 phases of interphase
H1, S, G2
What happens in the mitotic phase
duplicated chromosomes are aligned, separated and move to opposite pole of the cell and divided
what is karyokinesis
the first portion of the mitotic phase
what are the phases of karyokinesis
prophase,
prometaphase
metaphase
anaphase
telophase
what is cytokinesis
the sctond portion of the mitotic phase where physical separation happens
outcome of meiosis
4 haploid cells
outcome of mitosis
2 diploid cells
What is the nucleolus
area in the nucleus where rRNA biosynthesis occurs and where assembly of ribosomes begin
What are 80s romosomes composed of
40s subunit and a 60s subunit
which ribosomes are 80s
non organelle- associated ribosomes in eukaryotic cells
where are free ribosomes found
in the cytoplasm
what do free ribosomes do
synthesize water soluble proteins
where are membrane bound ribosomes found
attached to the rough endoplasmic reticulum
what do membrane bound ribosomes do
make proteins for insertion into the cell membrane or proteins for export from the cell
what is the endomembrane system
series of membrane tubules, sacs and flattened disks that synthesize cell components and move materials within the cell
what organelle make up the endomembrane system
endoplasmic reticulum
Golgi apparatus
lysosomes
vesicles
what is the endoplasmic reticulum
interconnected array of tubules and cistern in a single lipid bilayer
what are cisternae
flattened sacs
water lumen
the spaces inside of the cisternae
described the rough endoplasmic reticulum
studied wit ribosomes bound on the cytoplasmic side of the membrane
what do the ribosomes in RER make
proteins destined for the plasma membrane
what are transport vesicles
small sacs of RER contain ing new proteins that bud off and move to Golgi apparatus or plasma membrane or out of cell or other membrane
what are transport vesicles composed of
single lipid bilayer membranous spheres with hollow interiors
why is smooth endoplasmic reticulum smooth
it does not contain ribosomes
what does smooth endoplasmic reticulum do
biosynthesis of lipids, carb metabolism and detoxification of compounds in cell
what is the Golgi apparatus composed of
a series of membranous disks called dictyosomes, each having a single lipid bilayer, that are stacked together
what does the Golgi apparatus do
enzymes in it modify lipids from the ER, adding carbs to them, producing glycolipids, glycoproteins or proteoglycans
what are glycolipids and glycoproteins used for
inserted into the plasma membrane for signal recognition by other cells or infectious particles or cell surface receptors
What is exocytosis
the process where secretory vesicles release their contents to the cells interior
what do lysosomes contain
digestive enzymes
what do lysosomes do
break down food, damaged organelles or cellular debris, microorganisms or immune complexes
what are peroxisomes
membrane bound organelles that are not part of of the endomembrane sustem
what do peroxisomes do
produce hydrogen peroxide , degrade hydrogen peroxide and lipid biosynthesis
what are glyoxysomes
modified peroxisomes of yeasts and plant cells
what do glyoxysomes do
metabolic functions such as produce sugar molecules
what are glycosomes
modified peroxisomes made by certain trypanosomes, the pathogenic protozoans
What is the cytoskeleton composed of
microfilaments, intermediate filaments and microtubules
What are microfilaments composed of
two intertwined strands of actin composed of actin monomers forming filamentous cables
what do actin filaments do
work with motor proteins like myosin to effect muscle contraction in animals or amoeboid movement of some eukaryotic microbes
what are the forms of actin in ameboid organisms
a stiffer polymerized gel form and a fluid unpolymerized soluble form
what does actin in the gel form do
creates stability in the ectoplasm
what are pseudopodia
temporary extensions of the cytoplasmic membrane
how are pseudopodia produced
through forward flow of soluble actin filaments into the pseudopodia followed by gel-sol cycling of actin filaments resulting in motility
other than movement what do microfilaments do
cytoplasmic streaming
cleavage furrow formation
muscle movement
what are intermediate filaments
cytoskeletal filaments that act as cables within the cell
why are they called intermediate filaments
they are thicker than actin but thinner than microtubules
what are intermediate filaments composed of
several strands of polymerized subunits that are made of monomers
other functions of intermediate filaments
maintain position of the nucleus, form the nuclear lamina, anchor cells together in animal tissues
What are microtubules composed of
tubular dimers
what do microtubules do
form hollow tubes that are used as girders within the cytoskeleton,
what does endosymbiotic theory state
mitochondria originally arose through and endosymbiotic event in which bacterium capable of aerobic cellular respiration was taken up by phagocytosis into a host and remains as a vital component.
what are mitochondria composed of
two lipid membrane
what does the outermembrane of mitochondria do
it is a remnant of the original hosts cell membrane structure
what does the inner mitochondrial membrane come from
derived from the bacterial plasma bembrane
what is the mitochondrial matrix
location of metabolic enzymes, contains mitochondrial dna and 70s ribosomes ,
what cells contain chloroplasts
plant cells and algae
what are chloroplasts
organelles in which photosynthesis occurs
what are the membranes of chloroplasts
outer
inner
thylakoid
where is the chloroplast stroma
between the inner and outer membrane
what is the stroma
a gel-like fluid that makes up much of a chloroplasts volume and where the thylakoid system floats
what is the thylakoid system
a dynamic collection of folded membrane sacks where chlorophyll is found and photosynthesis occurs
what organelles are similar to mitochondria
hydrogenosomes
kinetoplasts
what do hydrogenosomes do
serve as the location of anaerobic hydrogen production , lack their own dna and ribosomes
what are kinetoplasts
a variation of mitochondria in some eukaryotic pathogens, there is a long branched mitochondrion where kinetoplast dna is found in one pole of the cell
how is the plasma membrane in eukaryotic cells different than prokaryotes
it contains sterols such as cholesterol that alter membrane fluidity, contain some specialized lipids including sphingolipids
what is endocytosis
uptake of matter through plasma membrane invagination and vacuole formation
what happens in phagocytosis
particles or other cells are enclosed in a pocket within the membrane which pieces off from the membrane to form a vacuole that completey surrounds the particle
what happens in pinocytosis
small dissolved materials and liquids are taken into the cell through small vesicles
what is receptor mediated endocytosis
endocytosis that is initiated by specific molecules called ligands when they bind to cel surface receptors on the embrane (how hormones, viruses and bacteria enter cells)
What is exocytosis
process where secretory vesicles release their contents to the cell exterior
What does the extracellular matrix help with
helps maintain shape and structural stability of cells without a cell wall.
how does the extra cellular matrix work
secretes a stick mass of carbs and proteins in between adjacent cells
how is eukaryotic flagella different than prokaryptic
it is flexible like a whip and has nine parallel pairs of microtubules surrounding a central pair of microtubules
what causes eukaryotic flagellum to bend
dynein motor proteins
