Leaves Flashcards
What are the main functions of leaves?
photosynthesis to create food and to maintain the water balance for the plant through transpiration
What chemical signal will trigger cell division at the apical meristem to form leaves?
auxin
Auxin will trigger cell division at the apical meristem, which will form
leaf primordium.
groups of cells that will form new leaves
leaf primordia
the location of leaf primordia is called
phyllotaxy
Cell division and expansion of the “” and “” in this area will produce a vascular strand which will eventually become the midvein and the epidermis.
procambium and protoderm
A layer of cells called the “” covers the entire surface of the leaf and is continuous with the “” of the stem
epidermis
the epidermis is covered with a “” layer
cuticle
openings in the epidermis are called “” and are borded by 2 gaurded cells which do contain chloroplasts
stomata
openings in the epidermis are called stomata and are borded by 2 “” which do contain chloroplasts
gaurd cells
”” regulate the opening and closing of the stomata, allowing the gasses necessary for photosynthesis to move into and out of the leaf
gaurd cells
water vapor also moves out of the leaf through the stomata by “”
transpiration
”” cools the leaf surface by evaporation and also helps pull water through the plant.
transpiration
Although transpiration, gas exchange for photosynthesis and respiration are vital to the plant, the plant must have the ability to close the gaurd cells to reduce water loss during times of stress (True/False)
true
the lower epidermis usually contains numerous “”, each formed by a pair of guard cells that regulate both evaporation of water vapor from the leaf and gas exchange between the interior and atmosphere.
stomata
”” do not contain chloroplasts
epidermal cells
what is the epidermis of a leaf covered with?
cuticle
high “” triggers leaf primordium
auxin
”” regulate the opening and closing of the stomata, allow the gasses necessary for photosynthesis to move into and out of the leaf
guard cells
”” cells will undergo cell division to thicken the leaf and to form the blade and petiole
meristematic cells
Gaurd cells will open and close in response to “”.
pressure changes
Gaurd cells open and close in response to environmentally induced pressure changes. The movement of “” and “” in response to light intensity, CO2 concentration or water concentration triggers pressure changes
potassium and water
What triggers pressure changes for the stomata to open and close?
movement of potassium and water
As potassium ions move, water follows by osmosis causing a change in “” in the guard cells.
cell shape
In the plasma membrane of guard cells there is a “”. The “” transfers protons out of the guard cells, which allows potassium to flow in and allows the stomata to open.
H+ pump
”” causes stomata to close by stopping to proton pump. By doing this, “” shuts off K+ from coming into the the guard cells, potassium and water flows out which causes the stomata to close
aba (abscisic acid)
Covering the surface of both the upper and lower epidermis is a waxy cuticle, which is only interrupted by the “”.
stomata
the “” varies in thickness that prevents gas exchange and excessive transpiration.
cuticle
what is the internal structure of the leaf composed of?
mesophyll, intercellular spaces, vascular tissue
this hormone will turn off the proton pump in response to a plant wilting.
ABA
In dicots, the “” has 2 regions and are not distinguishable in monocots.
mesophyll tissue
upper region of elongated cells, vertically arranged in 1-2 compact layers. contains 80% of chloroplasts.
palisade layer
lower region of irregular shaped cells loosley arranged. contained fewer layers. this is part of the mesophyll.
spongy layer
”” are abundant in the spongy mesophyll layer as a result of the loosley packed arrangement of cells.
intercellular spaces
a large number of air spaces in the leaf “” the surface area available for gas exchange
increases
leaf veins consist of a strand of “” and “”.
xylem and phloem
vascular tissue that transports from roots to leaves
xylem
vascular tissue that transports from leaves to roots, always source to sink
phloem
the vascular strand is surrounded by a “”, which functions in loading sugars into the phloem and unloading water from the xylem.
bundle sheath
”” are twice as efficient as “” plants in terms of fixing carbon (making sugar).
C4, C3
”” is useful for distinguishing between C3 and C4 plants.
bundle sheath
bundle sheath cells are “” with the mesophyll cells that are “” in a radial arrangement around the bundle sheath.
large, tightly packed
”” carbon fixation is less common in dicots than in monocots
C4
”” have only one type of mesophyll cell.
monocots
”” have two types of mesophyll cells.
dicot
”” lack a prominent bundle sheath.
C3
”” fixation occurs in the chloroplasts of mesophyll cells.
CO2
”” only use rubisco to fix CO2
C3
for carbon dioxide fixation In C4 plants, first “” fixes CO2 in cytosol of the mesophyll cells into C4 cpd (C3 + CO2 = C4)
PEP carboxylase
for carbon dioxide fixation in C4 plants, the second step is for C4 cpd from mesophyll cells is transported to bundle sheaths, where it is convered back to C3 cpd + CO2 and “” fixes CO2 + C5 to C6 in calvin cycle to make sugars in bundle sheaths.
rubisco
In C3 plants, they only use RuBP carboxylaase which can fix “” and “”.
carbon and oxygen
Carbon fixation occurs in the chloroplasts in the mesophyll cells (True/false)
true
where does co2 fixation take place in the chloroplasts?
stroma
when CO2 concentration gets low, oxygen starts competing for the binding site in rubisco and you end up with “” sugar.
5 carbon sugar
when CO2 concentration is high, rubisco will fix carbon into a “” sugar.
6 carbon sugar
A salvage pathway to allow C3 plants to survive under hot and dry conditions. it will use oxygen versus CO2.
photorespiration
”” absorb and store CO2 at night when the stomata are open and will keep the stomata close during the day.
CAM photosynthesis
similar to C4 photosynthesis.
CAM photosynthesis
