lecture 7 - Part II Flashcards
semiatonomous organelles
can grow and divide to reproduce themselves
example of semiautonomous organelles
mitochondria and chloroplasts
mitochondria
power plant of the cell
sites of aerobic respiration
converts food energy into a form of energy cells can use to power their reactions
contain their own DNA
inner membrane of mitochondria
convoluted with unfolding called crusted
large surface area that enhances productivity
where does ATP occur
on the crista
many steps of cellular respiration occur on the matrix
chloroplasts
member of a family of organelles called plastids
contains green pigment chlorophyll also enzymes and other molecules that function in photosynthesis
role of chloroplasts
capture light and energy and use some of the energy to synthesize organic molecules
what are the two reasons why mitochondria and chloroplasts are not apart of the edomembrane system
membrane proteins are not made by the ER bur rather ribosomes in the cytosol and their own ribosomes
each contains a small amount of DNA that codes for a small number of proteins within these organelles
endosymbiont theory
mitochondria in eukaryotic cells are thought to derive from bacteria like endosymbionts
what is the evidence that supports the endosymbiotic origin of plastids and mitochondria
- inner membranes of both have enzymes and transport systems that are similar to the plasma membranes of modern prokaryotes
- both replicate by splitting similar process to binary fission
- each organelle has a single circular DNA molecule
- these organelles contain trans, ribosomes and other molecules needed to translate DNA into protein
- ribosomes in mitochondria and plastids are similar to prokaryotic ribosomes in many ways
serial endosymbiosis
all eukaryotic cells have mitochondria
not all eukaryotes have chloroplasts
what is the hypothesis of serial endosymbiosis
supposes mitochondria evolved before plastids
non membranous organelles
ribosomes
nucleolus
centrioles
cytoskeleton
ribosomes
produced by nucleolus
present on rough ER
where protein molecules are assembled
nucleolus
located within the nucleus
main function of nucleolus
the production and assembly or ribosomes components
cytoskeletal
eukaryotic cells have a wide variety of distinct shapes and internal organization
cells are capable of changing their shape moving organelles
this requires a network of proteins placed in the cytoplasm known as cytoskeleton
what is the cytoskeleton composed of
microtubules
intermediate filaments
microfilaments
microtubules
cylindrical tubes
composed of polymers of a and b tubulin
functions of microtubules
shaping the cell
structures used for movement
inter/intra cellular transport
separating chromosomes
shopping the cell
helps support the cell and maintain shape
organizes the cell structures and activities
recent evidence suggests that the cytoskeleton may help regulate biochemical activities
structures for movement
structure and movement of cilia and flagella
cilia
numerous short extension in a cell that move back and forth
flagella
larger than cilia and move in an undulating manner
bacterial flagellum
driven by a rotary engine made up of protein located at the flagellum anchor point on the inner cell membrane
intracellular transport
vesicles can travel along paths provided by the cytoskeleton
dyne transports various cellular cargo by walking along cytoskeletal microtubules
separating chromosomes during cell division
centrosome can be an organelle within cells that includes two controles
centriole
made up of microtubules that are arranged in a specific way
where are centrioles found
found only in animal cells paired organelles are typically located together near the nucleus
what is the functions of centriole
move chromosomes during cell division
what is fungi
have centrosomes but no centrioles and therefor used other mechanisms to organize their microtubules during cell divison
intermediate fibers
filaments are the most stable and provide strength for the cell
larger than microfilaments but smaller than microtubules
made of fibrous proteins of the keratin family
not present in eukaryotic cells
microfilaments
primarily structural in function and are an important components of the cytoskeleton
thinnest filaments
composed predominantly of protein called actin
actin filaments
structural proteins made up of multiple subunits
two reasons why a band is mad beneath the plasma membrane
mechanical strength
links transmembrane proteins to cytoplasmic protein
actin fibres in skeletal muscle cells
the actin filaments are organized into regular arrays that are complementary with a set of thicker filaments formed from a second protein called myosin
extracellular matrix
complex layer outside the animal cell membranes
helps regulate cells
roles of extracellular matrix
providing support
segregating tissues from one another
adhesion to other cells
intercellular communication
differences between animal and plant cells
animal cells posses cell wall, chloroplasts, central vacuoles
lack centrioles and lysosomes
cell wall
fairly rigid layer surrounding a cell
external to cell membrane
what does the cell wall provide the cell with?
physical structure
filtering mechanisms
prevents over expansion when water enters the cells
cellulose
hard and rigid and has pores
plasmodesmata
plant cell are perforated with plasmodesmata
connecting channels that ;ink plant parts together
water and small solutes can pass freely
central vacuole
support for the cell
surrounded by a membrane called a tonoplasts
functions of the central vacuole
storing various compounds
disposing metabolic waster
maintain turgor
chloroplast
leaves are the major locations of photosynthesis
green color is from chlorophyll
main purpose of leaves
light energy absorbed by chlorophyll drives the synthesis of organic molecules in chloroplast
three different membranes of chloroplasts
two membranes make up the envelop that segregated the chloroplast from the cytoplasm
inner membrane encloses a fluid filled space called stroma
stroma
contains enzymes responsible for photosynthesis
thylakoids
membrane arranged unto flattened sacks
which organelles convert energy from nutrients or light to useful forms
mitonchdria and chloroplast
