plant growth Flashcards
xylem
dead cells made of lignin that perform transpiration( transport water and minerals from the high pressure roots to the low pressure leaves)
phloem
living cells that perform translocation- transports sucrose and amino acids around the plant depending on where it’s needed it is however an active process requiring energy
uses of glucose
starch- storage/reserves
oils/and fats(protection)
cellulose cell walls
respiration in the night
amino acids for protein synthesis (to produce protein also needs nitrate ions from soil)
photosynthesis
6CO2 + 6H2O → C6H12O6 + 6O2 (endothermic reaction requires light energy)+
limiting factors photosythesis
light intensity
carbon dioxide
temperature
factors affecting the rate of transpiration
temperature
humidity
light intensity
air movement
function of the stomata
to let out oxygen and let in CO2
also closes if too dry to prevent water loss
guard cells cause it t close
spongy mesophyll
gas exchange
letting oxygen diffuse out and CO2 diffuse in
(20% of photosynthesis) More air spaces
palisade mesophyll
site of photosynthesis (80%)
Regular box like structure
Most of the chloroplasts (cuz it’s at the top)
waxy cuticle
epidermis is water proof and prevents water loss via evaporation
meristem stem cells
regions of unspecialised cells in plants that are capable of cell division in any direction
they are found in certain parts of the plant though such as the tip of roots and shoots and in between the xylem and phloem.
companion cells
transport of substances in the phloem requires energy. One or more companion cells attached to each sieve tube provide this energy. A sieve tube is completely dependent on its companion cell(s).
sieve plate
specialised for transport and have no
nuclei. Each sieve tube has a perforated end so its
cytoplasm connects one cell to the next. Sucrose and amino acids are translocated within the living cytoplasm of the sieve tubes.
Flaccid
the cell is dehydrated and it pulls away from the cell wall becoming plasmolysed
Turgid
the cell is over hydrated and has become bloated sometimes bursting the cell wall
Hypotonic
too much water (lower concentration)
Hypertonic
Too little water (higher concentration)
Isotonic
balenced
osmosis in plants
osmosis is the diffusion of water molecules through a partially permeable membrane if a plant cell is placed in a hypotonic solution it will become turgid due to osmosis
uses of diffusion in plants
gas exchange in the spongy mesophyll
uses of active transport in plants
For plants to take up mineral ions, ions are moved into root hairs, where they are in a higher concentration than in the dilute solutions in the soil. Active transport then occurs across the root so that the plant takes in the ions it needs from the soil around it.
Lower epidermis
Bottom of the leaf
Upper epidermis
Translucent
To let light in
Physical barriers from pathogens
Vascular bundle
Xylem and phloem
