AP Bio - cells and organelles

cells

the basic structural and functional units of every organism

prokaryote

a cell that:

• contains bacteria and archaea

• DNA is in nucleoid region

• generally smaller in size than eukaryotes

eukaryote

a cell that:

• contains protists, fungi, animals, and plants

• DNA is in nucleus

• contain membrane bound organelles

chromosomes

a threadlike structure of nucleic acids containing genetic information in a cell

organelles

membrane bound structures in eukaryotes

nucleolus

dense region of the nucleus where rRNA is synthesized

ribosomes

found in bacteria

comprised of RNA and proteins, 2 subunits

synthesize proteins

makes membranes

rough ER

contains ribosomes bound to ER membrane

synthesizes proteins

makes membranes

continuous w/ nuclear envelope

smooth ER

contains no ribosomes

continuous with nuclear envelope

stores calcium ions

synthesizes lipids, metabolizes carbohydrates, and detoxifies the cell

autophagy

allows the cell to renew itself, ability of lysosomes

lysosomes

membranous sac with 40 different hydrolytic enzymes

breaks down ingested substances, old organelles

works best at pH 5, proton pumps maintain that

peroxisomes

similar to lysosomes

membrane-bound metabolic compartment

catalyze reactions that produce H₂O₂

center of redox rxns → neutralize H₂O₂ to H₂O

golgi

flattened membrane sacs separate from the cytosol

has directionality

processes, sorts, and ships proteins synthesized in the RER

nucleus

contains chromosomes

• enclosed by nuclear envelope

• double membrane

• has pores

  • regulate entry and exit of materials from the cell

vacuoles

large vesicles that stem from the ER and Golgi

used for storage of water and ions

maintaining water levels in cell

in seeds, filled with proteins

in flowers, contain pigments

some digest/ recycle macromolecules

mitochondria

site of cellular respiration

• outer membrane is smooth

• inner membrane has fold called cristae

  • divides mitochondria and increases surface area

amino acid and vitamin synthesis

regulates apoptosis

chloroplast

specialized organelles in photosynthetic organisms

contain chlorophyll

stroma

location for Calvin cycle

contains:

• chloroplast DNA

• ribosomes

• enzymes

actin filaments purpose

1. maintain cell shape by resisting tension

2. move cells via muscle contraction

3. divide animal cells in 2

4. move organelles

grana

a group of thylakoids

increase surface area

• light dependent reactions happen here

thylakoids

membranous sacs present in chloroplasts

• light dependent reactions occur in grana

intermediate filaments

• about 10nm in diameter

• one type of various proteins (keratins, laminins, etc)

  • 70 types in humans

• do not have polarity, nor motor proteins, and primarily play a structural role in cells

  • intracellular keratin provide mechanical strength to cells and resist pressure

  • secreted keratins form fingernails, toenails, hair

microtubules

hollow, rodlike structures made from the protein tubulin

• grow from the centrosome

• assist in microtubule assembly

largest cytoskeletal elements, 25 nm in diameter

• tubulin: dimer made of a and B subunits

directionality, highly dynamic

actin

a protein present in eukaryotic cells that plays a role in muscle contraction, movement, and structure

cilia

short, hair like structures present on the outside of the cell that assist in movement

flagella

organelle that enables movement and chemotaxis

plasma membrane

selectively permeable membrane with a bipolar layer and embedded proteins

cisternae

flattened, membranous sacs that make up golgi

• important part of packaging and modifying proteins

endomembrane organelles

nuclear envelope

endoplasmic reticulum

golgi complex

lysosomes

vesicles/ vacuoles

plasma membrane

energy organelles

mitochondria

chloroplasts

compartmentalization

• increases surface area

• prevents interfering reactions from occurring in the same location

ribosomes can be found in

the endoplasmic reticulum or nuclear envelope

golgi cis face

receives vesicles from the ER

faces the ER

golgi trans face

sends vesicles out into cytosol to other locations or to plasma membrane

faces the PM

golgi body function

packages materials into new transport vesicles that exit the membrane via exocytosis

er and golgi

vesicles come from

endosymbiont theory

the theory that explains the similarities mitochondria and chloroplasts have to a prokaryote

evidence of endosymbiont theory

1. double membrane

2. ribosomes

3. circular DNA

4. can replicate

cellular respiration

takes place in mitochondria

intermembrane

space between inner and outer membrane (mitochondria)

mitochondrial matrix

enclosed by inner membrane

• location for krebs cycle

• contains:

  • enzymes that catalyze cellular respiration to produce ATP

  • mitochondrial DNA

  • ribosomes

more mitochondria

the higher the metabolic activity, the ____ _______

cytoskeleton

network of fibers throughout the cytoplasm

• give structural and mechanical support

• anchor organelles

• allow for movement of vesicles and organelles or the whole cell

• motor proteins help

• assist in cell division

microtubules, microfilaments, intermediate filaments

3 types of fibers in cytoskeleton

microtubule

• hollow, rod like

• tubulin

• grow from centrosome

• serve as “train tracks” for organelles and the cell

• separates chromosomes during mitosis\

• cilia and flagella

transcription

DNA → RNA → protein

food vacuole

forms via phagocytosis

aids in digestion

contractile vacuole

maintain water level in cells

central vacuole

found in plants

contains ions and water

turgor pressure → plant rigidity

mitochondria characteristics

enzymes → ATP

mitochondrial DNA

ribsomes

chloroplast characteristics

enzymes

chloroplast DNA

ribosomes

actin filaments

• monomer: g-actin (globular actin)

• polymer: f-actin (filamentous actin)

• smallest in diameter of the 3 filaments

• ATP hydrolysis powers polymerization

• rate of growth faster at + end

• in muscle cells

intermediate filaments

• made of various subunits

• permanent cell structure

• anchor nucleus in place

  • form nuclear lamina

1. proteins

2. nucleic acids

3. carbohydrates

4. plasma membrane

all cells have

directs the catalytic steps of protein synthesis

rRNA

long filaments that rotate to propel the cell

flagella

needlelike projections that promote attachment to other cells or surfaces

• important to colonization

fimbriae

many prokaryotes have _______ __________ membranes

• convert energy in sunlight to chemical energy

• develop from folds of plasma membrane

internal photosynthetic

• branched tails of plasma membrane

• isoprenoid tail rather than fatty acids

archaea plasma membrane

cell wall made of peptidoglycan

bacteria

thick layer of peptidoglycan, stains

gram +

thinner layer of peptidoglycan, does not stain

gram -

organelles + cytosol, interior of the cell

cytoplasm

myosin

motor protein that converts chemical energy in ATP into mechanical work

microtubule function

1. provide stability by stiffening cells

2. anchor organelles

3. separate chromosomes in mitosis

4. move organelles

5. mediate movement of cilia & flagella

kinesin and dyenin

move along microtubule tracks

ribosomes and rRNA

“zip code” in endomembrane system

signal recognition peptide, SRP receptor

“mail carrier” in endomembrane system

translocon

“mail slot” in endomembrane system

mannose 6-phosphate

each protein that comes out of golgi and is destined for the lysosome has a specific molecular tag

• modified with _______ __ __________ residues

motor protein that moves along microtubules, transporting cargo toward the plus end (away from centrosome)

• plays key role in cellular transport

• moving organelles, vesicles, mitotic spindle components

kinesin

microtubule based motor protein, moves toward the minus end (toward centrosome)

• retrograde transport in neurons, positioning organelles, powering movement of cilia and flagella

dyenin

motor protein that moves along actin filaments instead of microtubules, involved in muscle contraction, intracellular transport, and cell motility

• muscle contraction, vesicle transport, cytoskeletal organization

myosin