Cells Flashcards
in biology ___ and _____ closely reflect function.
form and structure
what is plant physiology?
how plants function and work
What is the function of stems?
support and transport
what is the function of leaves?
photosynthesis
what is a cell?
structural unit of multicellular organisms
what is the order of organizational hierarchy in plants
cells, tissues, organs, and plant body
what are organelles?
sub-cellular structures
what is the dominant part of extracellular matrix (ECM)?
cell wall
what does the cell wall provide to plant cells?
strength (support) and protection
what is a cell’s first line of defense?
cell wall
________ cell walls are synthesized in actively growing, young, and expanding cells
primary
_________ cell walls are deposited as the cells mature
secondary
are secondary cells walls expanding and growing?
no they are not only primary
what cell wall type is thicker and more rigid?
secondary
what cell wall type is a major component of wood?
secondary cell wall
what component is the secondary cell wall made of?
lignin
________ ________ is what is wood is composed of
secondary xylem
what is lignin
highly complex phenolic compound
what component is the primary cell wall made of (3)
cellulose, hemicellulose, and pectins
what component of the cell wall acts like glue to cross link cellulose and hemicellulose?
lignin
what is the most abundant organic compound in nature?
cellulose
what cell wall components give the cell its shape and are embedded in a sea of pectins?
cellulose and hemicellulose
refer to cellulose in engineer terms
it is a composite material like concrete
why have cellulose and lignin received a lot of attention in recent years?
biofuel
why is not much information known about lignin?
it is very very difficult to break down in order to study its composition
what is the cementing material that holds together adjoining cells
middle lamella
the middle lamella connects _____ cell wall to ______ cell wall
primary to primary
what are the components of the middle lamella?
pectins cross linking with Ca 2+
what is the organic compound that gives stiffness to jelly byproduct of fruit such as apples or guava
pectins
what nutrient is crucial for the cell wall and plasma membrane structural integrity?
Ca 2+
what fungal disease in potato is a result of the breakdown of the middle lamella?
potato soft rot (postharvest)
how can soft rot of potatoes be mitigated?
providing Ca directly to the tuber through the tuber roots
what is protoplasts
living part of the cell inside the cell wall
what is the cytoplasm?
protoplasts excluding the cell vacuole and nucleus
what cell part is the command center
nucleus
what cell part contains most of the genes
nucleus
what are chromosomes?
DNA organized along with protein
what is nucleolus?
production of ribosomes
what are involved in protein synthesis
ribosomes
what process do plants absorb water through?
osmosis
when osmosis occurs _____ expands
vacuole
what % of cell volume does the vacuole occupy?
90%
what is a tonoplast?
membrane bound sacs
is a vacuole a tonoplast?
yes
when does a cell exert turgor pressure?
when the vacuole expands
what happens during turgor pressure resulting in cell expansion
plant growth, seed germination, and flower/stomata opening
what is turgor pressure?
pressure within a cell resulting from entry of water into the vacuole
what is the strength of hydrostatic pressure?
~12 bars
what serves as disposal sites for metabolic byproducts
the vacuole
define anthocyanins
the pigments that give fruit and flowers their color
where are anthocyanin pigments located
the vacuole
what surrounds the cytoplasm
cell membrane
what regulates the flow of nutrients and water
plasma membrane
the plasma membrane is ______ permeable
differentially
define differentially permeable
allows the passage of water and some solutes but blocks the passage of others
what is meant by the fluid mosaic model?
in the plasma membrane lipid bi-layer and proteins it is a protein mosaic floating in a lipid bilayer
What are colligative properties?
chemical properties of solutions that depend on the number of particles (ions) in the solution
what influences colligative properties
osmolarity
what are examples of colligative properties?
boiling point elevation, vapor pressure, and freezing point depression
the ____ the osmolarity the lower the freezing point
higher
the the _______ the osmolarity the higher the boiling point
higher
1 osmolar freezing point is about ___ degrees C
-1.8
cells of freeze hardy plants tend to accumulate ____ in their cells
solutes
what lowers the freezing point of cell sap
solutes in the cell accumulated
solutes accumulated in the cells prevents what?
intra cellular freezing
is freezing inside the cell (intracellular) lethal always?
yes
what reduces the amount of desiccation and extra-cellular ice?
accumulation of solutes in the plat cells
what are 3 microscopic techniques for distinguishing between a dead and living cell?
plasmolysis/deplasmolysis, cytoplasmic streaming, and vital staining
what is cytoplasmic streaming?
the movement of cytoplasm
if cytoplasmic streaming occurs are plant cells living or dead?
living
what are the dots in a cell that move during cytoplasmic streaming?
protoplasts
what does plasmodesmata do?
transport molecules between cells and facilitate cell to cell communication
what occurs in vital staining
the protoplasts of only living cells are colored by certain stains
if cells maintain their differentiating permeable properties are they living or dead
living
osmolarity is influenced by the number of _____
particles
osmolarity is
the basis of how water moves in plant cells
water moves from _____ osmolarity to ______ osmolarity
lowest to highest
