Plant Part Of Midterm

Updated 2007-05-23 23:12
Question Answer
Lenticels- loose aggregation of cork cells that moves O2 by diffusion to the inner bark
What happens to the thickness of wood every year?It increases but stays more or less constant because its always producing 2 phloem which pushes 1 phloem off
Inner bark-functional part in transporting minerals and water which is part of 2 phloem
Outer bark-crushed 1 phloem made of cork and cork cambium
Vascular cambium- between inner bark and sapwood
Sapwood-not plugged and is functional in transporting minerals and water
2 xylem-consists of heartwood and sapwood
Heartwood- discolored where vessels and tracheids are plugged with resin and gums no transportation of H2O
Pith-may or no be there in a 200 year old stem
1 xylem-to the right of pith in 200 year old stem
List three root functions- 1. Anchors plant 2. Transports/absorbs H2O 3. Uses secondary metabolites (nicotine) as a defense
What are the three zones of a root?1. Cell division 2. Cell elongation 3. Cell maturation
From inside to outside list the three types of tissue in a root-1. Vascular tissue 2. Ground tissue 3. Epidermal tissue
Apical meristems- are present at tip of stem and root to increase their length
3 functions of a Root cap-protects root from abrasive soil, secretes mucilaginous(mucigel) material (lube) and determines direction of growth
Root hair-a long extension of an epidermal cell and has internal growth to increase SA for absorption.
Where do root hairs grow and Why doesn’t root hair growth happen in the elongation zone?They grow in the maturation part of the root Because the root hair would be sheared off by soil
What establishes the pattern of tissue development?3 primary meristems
What are the 3 primary meristems? Protoderm, ground meristem, procambium
Casperian strip-(1 xylem)-endodermal cells secrete this waxy layer made up of a water-repellent compound called suberin. It prevents water from creeping through the walls of an endodermal cells and preceding to the vascular tissues which is important because water and solutes moving through cortex can reach vascular tissue only by passing through plasma membrane of endodermal cells. (some things can get in while others cant)
Three Functions of the pericycle-1. Initiate lateral roots 2. Contribute to vascular cambium 3. Produces first cork cambium
Stage #1 of pericycle( in mature primary state)-mass of meristematic cells form lateral root
Stage #2 of pericycle (in mature primary state)-develops into root apex
Stage #3 of pericycle (in mature primary state)-enlongation
What is the function of the blade of a leaf?It is usually thin and flat for surface area to capture photons
Function of photosynthesis-CO2 + H2O + photons à CHO (reduced carbon)+ O2
Top of the leaf-epidermis which reduces water being lost
Palisade- the upper layer of ground tissue in a leaf consisting of and elongated cells beneath and perpendicular to the upper epidermis and constituting the primary area of photosynthesis
What does the palisade cell look like? It has a thin layer of chloroplasts across the outside of the cell, most of cell is exposed to the inside and only a few areas of cells are touching even though they are closely packed…minimize the area CO2 has to diffuse because its closely packed.
Spongy mesophyll- middle of leaf…the lower layer of ground tissye that contains irregularly shaped parenchyma cells with few chloroplasts and large intercellular spaces and site of most gas exchange
Why is spongy mesophyll loosly packed?If it wasn’t then CO2 can’t be given to chloroplasts
What percent of CO2 enters through the stomata?95%
Stomata-allows carbon dioxide to enter photosynthetically active tissues found in epidermis
What do stomata consist of and what do they do?Guard cells that change shape in order to open or close a pore.
What happens when stomata opens?CO2 and O2 and water vapor and other gases move between atomosphere and interior of plant through diffusion.
When do stomata open?It’s favorable When photosynthesis environment
Secondary metabolites- plant poison
Vein-delivers water and minerals top has primary xylem while bottom has primary phloem
What causes the flat shape of a vein- torpor pressure
Bundle sheath- surrounds veins and vascular bundles in the mesophyll of leaf and functions as tranfer cells taking glucose from mesophyll, making sucrose and dumping it into sieve-tube element

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