ap bio cytology quiz Flashcards
what is the cell theory
1) all living things are made of cells
2) cell is simplest collection of matter that can live
3) cell structure is correlated to cellular function
4) all cells are related by their descendant from other cells
cell fractionation
takes cells apart and separates the major organelles from each other
what does cell fractionation help with
allows scientists to determine functions of organelles
eukaryotes
differentiated cells
protists, fungi, animals, plants
prokaryotes
single cell, no nucleus
archae, bacteria
similarites between eukaryotes and prokaryotes
plasma membrane, semifluid substance (cytosol), chromosomes, ribosomes
differences between eukaryotes and prokaryotes
prokaryotes- no nucleus, DNA in unbound region (nucleoid), no membrane bound organelles, cytoplasm bound by plasma membrane
eukaryotes- DNA in nucleus bounded by membranous nuclear envelope, membrane bound organelles, cytoplasm in region between plasma membrane and nucleus, larger than prokaryotes
plasma membrane
- selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service volume of every cell
- general structure is double layer of phospholipids
- 4 ring carbon and cholesterol
limits to cell size
cells have greater surface area relative to volume
metabolism sets limits
what do eukaryotes have that partitions cell into organelles
internal membranes
what are the eukaryotic organelles
nucleus, nuclear lamina, chromatin, chromosomes, nucleolus, ribosomes, endomembrane system, mitochondria, chloroplasts, peroxisomes, mitochondria, chloroplasts, cytoskeleton
nucleus functions
1) houses genetic material
2) most conspicuous organelles
3) nuclear envelope
4) nuclear membrane
5) pores
nuclear envelope
encloses nucleus separating from cytoplasm
nuclear membrane
double membrane, all consists of lipid bilayer
nuclear pores
regulate entry and exit of molecules from nucleus
nuclear lamina
maintains shape of nucleus, composed of protein (lamin)
chromatin
DNA and proteins form genetic materials
chromosomes
condensed chromatin
nucleolus
located within nucleus
contains ribosomes
site of ribosomal RNA synthesis
carries out protein synthesis
found in both eukaryotes and prokaryotes
nucleolus protein synthesis
in cytosol–> free ribosomes
outside of endoplasmic reticulum or nuclear envelope–> bound ribosomes
endomembrane system
regulates protein traffic and performs metabolic functions in cell
contains
- nuclear envelope
- endoplasmic reticulum
- golgi apparatus
- lysosomes
- vacuoles
- plasma membrane
all are either continuous or connected via transfer by vesicles
endoplasmic reticulum
accounts for more than half of total membrane in eukaryotic cells
continuous with membrane
2 regions- smooth and rough ER
plants and animals, not bacteria
smooth ER
lacks ribosomes
synthesizes lipids
metabolizes carbohydrates
detoxifies poison
stores calcium
rough ER
ribosomes studding surface
bound ribosomes secrete glycoproteins
distribute transport vesicles (proteins surrounded by membrane)
membrane factory for cell
glycoprotein
proteins covalently bonded to carbohydrates
golgi apparatus
shipping and receiving center
consists of cisternae
modifies products of ER
manufactures certain macromolecules
sorts and packages materials into transport vesicles
cisternae
flattened membranous sacs
entire thing is the golgi
lysosomes
membranous sac of hydrolytic enzymes that digest macromolecules
digestive compartments
endures phagocytosis and autophagy
what do the enzymes do in lysosomes
hydrolyze proteins, fats, polysaccharides, and nucleic acids
phagocytosis
cells can engulf another and forms food vacuoles
fuses with food vacuoles and digests molecule
autophagy
uses enzymes to recycle cells organelles macromolecules
vacuoles
diverse maintenance compartment
- contractile vacuole
- food vacuole
- central vacuole
contractile vacuole
found in freshwater protists
pump excess water out of cells
food vacuole
formed by phagocytosis
central vacuole
found in many mature plant cells
hold organic compounds and water
metabolic activity group
mitochondria, chloroplast, peroxisome, cytoskeleton
mitochondria
sites of cellular respiration that generates ATP
in eukaryotic cells
contains cristae
mitochondrial matrix and intermembrane space
cristae
smooth outer and inner membrane folded together
presents large surface area for enzymes to synthesize proteins
mitochondrial matrix and intermembrane space
inner membrane creates 2 compartments
mitochondrial matrix catalyzes metabolic steps of CR
chloroplast
found in plants and algae (plants and other green organs)
sites of photosynthesis
belongs to plastids (organelle family)
contains chlorophyll (green pigment)
contains enzymes and other molecules functioning in photosynthesis
thylakoids for structure
thylakoids
membranous stacks that form granum and stroma (internal fluid)
peroxisomes
oxidative organelle
specialized metabolic compartments bounded by single membrane
produce hydrogen peroxide and convert to water
oxygen is used to break down different types of molecules
mitochondria and chloroplast structure
change energy to form to another
not part of endomembrane system
double membrane
contain proteins made by free ribosomes
contain own DNA
cytoskeleton
network of fibers extending throughout cytoplasm
organizes cell structure and activity, anchors organelles
- microtubules
- microfilaments
- intermediate filaments
supports cells, maintains shape
interacts with moto proteins (mobility)
may regulate biochemical activities
vesicles travel along ‘monorail’ provided by cytoskeleton
microtubule
thicket component
microfillament
thinnest component
intermediate
fibers w diameters in a middle
microtubules
shape cell
guide movement of organelles
separates chromosomes during cell division
contains centrosomes and centrioles
contains cilia and flagella
centrosomes and centrioles
microtubules grow out from centrosome, near nucleus
centrosome is microtubule- organizing center
animal cells
- centrosome has pair of centrioles
cilia and flagella
microtubules control beating of cilia and flagella (locomotor appendages of cells)
share common ultrastructure
cilia and flagella ultrastructure
core of microtubules sheathed by plasma membrane
basal body anchors cilium or flagella
motor protein (dynein) drives bending movements of cilia or flagellum
microfilaments (actin filaments)
built as twisted double chain of actin subunits
bears tension, resists pulling forces in cell
forms 3D network (cortex) inside plasma membrane
- helps support cell shape
bundles of microfilaments make up core of microvilli intestinal cells
function in cell mobility and contain myosin protein (also actin)
muscles cells have thousands of actin filaments arranged parallel to one another
thicker filaments compose of myosin interdigitate with thinner actin fibers
localized contraction brought about by actin and myosin
-drives amoeboid movement
pseudopodia
cellular extensions
extend and contract through reversible assembly and contraction of actin subunits into microfilaments
cytoplasmic streaming
circular flow of cytoplasm within cell
streaming speeds distribution of materials within cell
plant cell
- actin- myosin interactions and sol-gel transformations drive cytoplasmic streaming
cell walls of plants
extracellular structure that distributes plant cells from animal cells
prokaryotes, fungi, some protists
protects plant cell, maintains shape, prevents excessive water uptake
make of cellulose fibers embedded in polysaccharides and proteins
how many layers do cell walls have
3
plasmodesmata
channels between adjacent plant cells
