Chapter 4 Flashcards
who discovered cells and when?
Robert Hooke in 1665
who proposed cell theory and when?
Schleiden and Schwann in 1840
list the three rules of cell theory
- all living things are composed of cells
- cells are the smallest living things
- cells arise only from other cells
can cells be any size?
no, cell size is limited
why is cell size limited?
as size increases, the surface area to volume ratio decreases, and diffusion becomes less efficient, this is why cells are microscopic
what are the three structures that all cells have in common?
- plasma membrane; cell boundary
- cytoplasm; also called cytosol
- DNA; requirement for life
what is the primary characteristic of prokaryotic cells?
they lack membrane bound organelles
what are the two types of prokaryotic cells and where are they found?
- acteria; everywhere
2. archaebacteria; found in limited, extreme environments, likely the first cells to evolve
what structures do prokaryotic cells possess? Don’t put Cheese on your PopCoRN
DNA Cytoplasm Plasma membrane Cell wall Ribosomes No membrane bound organelles
what are two extracellular structures that some, but not all prokaryotic cells have?
flagella and pili
what do prokaryotic cell walls do?
protect and maintain structure/shape
what are prokaryotic cells composed of?
combination of proteins and sugars called glycoproteins
what do the flagella of prokaryotic cells do?
allows cell to move and change location
what do the pili of prokaryotic cells do?
anchors cell in place
what does the envelope of prokaryotic cells do?
further protects cell from harsher environment, is typically gelatinous, can be glycoprotein structure
what is the biggest difference between prokaryotic and eukaryotic cells?
eukaryotic cells possess membrane bound organelles, they are also more complex, compartmentalized, and have more support and structure, they also have mitochondria
what does the nucleus do?
stores DNA
what is the nucleus surrounded by?
nucleoplasm, a phospholipid bilayer
what is chromatin?
DNA’s less organized form, an unwound loose chain for the cell to use easily
what is the endoplasmic reticulum?
Rough ER and Smooth ER, right outside the nucleus, protein and lipid synthesis
what is the nuclear membrane/envelope?
it surrounds the nucleus and has NUCLEAR PORES to allow DNA info out
what is the nucleolus?
where RNA baker is stored and organized, darker region in nucleus
what is special about cancer cells?
they have multiple nuceoli to handle cell divisions
what are ribosomes?
OVENS!
site of protein synthesis
composed of RNA
large and small part joined together (oven and oven door?)
where are the ribosomes located?
embedded in the ER and floating free in the cytoplasm
where is the endomembrane system located?
nuclear pores, through endoplasmic reticulum, inside cell cytoplasm
what does the endomembrane system do?
synthesizes protein, gets it into correct form, moves it through ER, synthesizing and folding, packages it to move to golgi, where it is folded and packaged into its final form, and expelled out through vesicles
what composes the endomembrane system?
- nuclear membrane
- ER
- golgi body
- transport vesicles
- plasma membrane
Are ribosomes part of the endomembrane system?
No
What does the rough endoplasmic reticulum do?
Protein synthesis
Where is the rough ER located?
Closest to the nucleus
What do the smooth ER do?
Early protein packaging for Golgi apparatus, and some toxin filtration
what does the rough ER do?
protein synthesis
what does the smooth ER do?
early protein packaging for golgi, toxin removal
what does the golgi apparatus do?
final protein packaging, lipid synthesis
what are the vacuoles?
membrane bags
what do the vacuoles do?
move things from place to place in endomembrane system, containers for digestion
what are the two types of vacuoles?
transportation and digestion
what is endocytosis, and what organelle accomplishes it?
to move into the cell, using a vesicle/vacuole
what is the type of endocytosis that WBC’s do?
phagocytosis, cell eating
what is exocytosis?
to move out of the cell using a vesicle/vacuole
what is the function of mitochondria?
ATP formation
POWERHOUSE OF THE CELL
how does mitochondria create cell energy
converts glucose to ATP
is mitochondria found in eukaryotic cells, prokaryotic cells, or both?
eukaryotic cells only
what is so special about mitochondria?
they have their own DNA
what is the structure of mitochondria?
kidney bean shaped, inner and outer membranes, space between inner membranes called a matrix
what cells have chloroplasts?
plant and algae cells, SOME protists
describe the structure of chloroplasts
outer and inner membranes, membrane bound sacks to increase surface area
what is so special about chloroplasts?
they have their own DNA
what is the theory about prokaryotes and mitochondria/chloroplasts?
eukaryotic cells may have formed from the symbiotic relationship between protists and the mitochondria/chloroplasts they engulfed
what are the three protein fibers of the cytoskeleton?
microfilaments, intermediate filaments, and microtubules
what is the structure of microtubules?
two intertwined strands of the globular protein, actin
what are microfilaments also called?
actin filaments
what is the function of microfilaments?
they serve as a track for myosin, which enables motion, like cell division in animal cells and cytoplasmic streaming in plant cells, they provide rigidity and cell shape, can depolymerize (dissassemble) and reform quickly, which allows WBC’s to move and eat pathogens
what happens when actin and myosin filaments pass each other?
muscle contraction
what kind of cells have a lot of microfilaments?
muscle cells!
what is the structure of intermediate filaments?
several strands of fibrous protein wound together
what is the function of intermediate filaments?
bear tension to maintain cell shape, anchor nucleus and other organelles in place, create cell’s supportive inner scaffolding
which is the most diverse of the cytoskeletal elements?
intermediate filaments
give an example of an intermediate filament/fibrous protein
keratin
do all cytoskeletal elements play a role in cell movement?
no, intermediate filaments do not
what is the structure of microtubules?
small, hollow tubes with walls made of two globulin proteins
what is the function of microtubules?
help cell resist compression, provide a track for vesicles to move throughout the cell, pull replicated chromosomes to opposite ends of the cell, can dissolve and reform quickly, structural elements in flagella, cilia, and centrioles
how do cells move?
by cytoplasmic streaming, or crawling/streaming through use of pseudopods
give an example of cytoplasmic streaming
plants moving their chloroplasts to a location with more sunlight
give an example of cell crawling through use of a pseudopod
White Blood Cells send their membrane out to form a pseudopod, and their cytoplasm follows
what is the structure of flagella?
long and whip-like
give an example of a special cell with a flagellum that can move outside our bodies?
sperm cells
what are cilia?
short, external structure that beat in unison
WE ALL ROW
give an example of cilia
they line our trachea and beat upward so we don’t inhale bad stuff when breathing
what is the structure of flagella and cilia?
microtubules in 9 pairs outside in a circle, 2 pairs inside, with protein and ATP connecting the inside and outside like spokes of a wheel
how do flagella and cilia move?
ATP causes rotation and propulsion
what can extracellular structures be used for?
movement
is the exterior of a cell completely smooth?
no, phospholipid bilayer, proteins, collagen, glyoproteins, and fibers make a gooey matrix
what are cell walls composed of?
structural carbohydrates;
cellulose in plants, chitin for fungi
what is the gap in the cell wall that allows for communication between adjoining cells?
plasmodesma
what does the extracellular matrix (ECM) do?
allows cells to be tightly joined together through cytoskeletal intermediate filaments?
is the bond strength of the ECM always the same?
no it varies by cell type;
tighter in cardiac cells, not as tight is muscle cells
