Leaf Anatomy

Question 1

main functions of leaves

Answer 1

traspiration:regulate water levels
photosynthesis
-need large SA for these

Question 2

How does the leaf form

Answer 2

-Chemical signals (IAA) sent and apical meristem forms LEAF PRIMORDIUM
-proctoderms and procambium produce vascular strand that become midvein and vascular strand
-the meristematic cells thicken leaf and produce lamina(blade) and petiole(stem thing)

Question 3

The leaf primordium position determined by the

Answer 3

phylotaxy

Question 4

until when does leaf uses plant resources?

Answer 4

until 40% grown

Question 5

Cuticle covers the

Answer 5

epidermal layer

Question 6

epidermis does not usually contain

Answer 6

chloroplasts

Question 7

do guard cells contain chloroplasts?

Answer 7

yes

Question 8

what are the openings in the epidermis called? what controls them?

Answer 8

-they are called stomata( stoma singular)
-guard cell controls them, controlling gasses necessary for photosynthesis, and transpiration

Question 9

why must the stomata close if the gas and water exchanges are important to the plant?

Answer 9

water loss

Question 10

how do guard cells open and close?

Answer 10

-movement of potassium and water in response to light intensity
-co2 or water concentration triggers these pressure changes
-as potassium ions move, water follows by osmosis, changing shape of guard cells

Question 11

How does proton pump work

Answer 11

transfers protons out, and then k+ rapid intake
if there is H+, guard cells closed
no H+, guard cells open

Question 12

what hormone inhibits proton pump

Answer 12

ABA, abscisic acid

Question 13

what is the internal structure of leaf made of

Answer 13

mesophyll tissue,
intercellular spaces
vascular tissue

Question 14

monocot vs dicot msophyll

Answer 14

monocot have t type of mesophyll
dicot have 2

Question 15

Palisade mesophyl

Answer 15

made of 2 layers sof longated cells
80% of chloroplasts

Question 16

Spongy layer

Answer 16

-intercelular spaces
-most gas exchange is here
-fewer chloroplasts

Question 17

what is vascular strand surrounded by?

Answer 17

vascular bundle

Question 18

vacsular tissue composed of

Answer 18

xylem- vessel and tracheids
phloem- sieve cells and companion cells

Question 19

what does vascular bundle do

Answer 19

helps load sugars to phloem and unloads water from xylem

Question 20

C3 photosynthesis

Answer 20

-Do not have predominant bundle sheath
-RUBC fixes CO2 to sugar in chloroplasts of mesophyll

Question 21

bundle sheath

Answer 21

-in C4 plants, has tightly packed mesophyll cells
-aid vascular bundle transport water to epidermis
-aids in converting CO2 to sugar

Question 22

C4 photosynthesis

Answer 22

-PEP fixes CO2 into C4 molecule in cytosol of mesophyll.
-then transported to bundle sheath, where it is converted back into C3+ CO2
-in calvin cycle, CO2 fixes to C5 to make C6 for sugars in bundle sheath

Question 23

CAM

Answer 23

at night, PEP binds C3to C4, which accumulates in the vaccuole
during day, C4 diffuses out of vaccuoles and CO2 released for calvin cycle–>rusisco and co2 fixation

Question 24

What happens if no CO2 intake for photosynthesis? (C3)

Answer 24

Bind O2 to rubisco,
leads to no carbon fixing, however saves plant from oxygen accumulation
–> photorespiration

Question 25

Photorespiration

Answer 25

dissipates ATP and accumulated elections to prevent photooxidative damage

Question 26

modified leaves

Answer 26

adapted to trap insects
leaf tendrils(support)
leaf spines(protection)
reduction in transpiration
water or food storage
asexual propogation
specialized to form flowers

Question 27

leaves modified to reduce water loss thru transpiration

Answer 27

reduction of size
leaf blade rolled
pitted or sunken stomata