FINAL OF FINALS Flashcards
perennials that create stiff structures above ground
Woody Plants
Types of woody plants
Trees
Shrubs
Vines
climb on other plants or on inanimate
structures like a fence or a wall
Vines
“backbone” for support
Wood
“skin” for protection
Bark
only part of the trunk that is alive
Cambial layer
transports water and mineral salts from roots to the other parts of the tree
Xylem
transports sucrose and amino acids between the leaves and other parts of the plant
Phloem
The old xylem becomes
wood
The old phloem becomes
the bark
an aggregate of untold number of small
units called cells.
Wood
It is an intercellular substance that separates wood cells
Middle lamella
In each cell, there is a wall enclosing a lumen which contains a vital plant substance called
Protoplasm
the living part of the cell, which comprises of different cellular organelles.
Protoplasm
It is a jelly-like, colorless, transparent, and viscous living substances present within the cell wall
Protoplasm
The substance present between the cell
membrane and the nucleus.
Cytoplasm
What does protoplasm contains?
cytoplasm and the nucleus.
What does cytoplasm contain?
cell organelles like Golgi bodies, endoplasmic reticulum, mitochondria, ribosomes, but no nucleus.
Jelly-like fluid containing water, proteins
and metabolic wastes.
Cytoplasm
What are the chemical composition of wood and their corresponding %?
Lignin 15-25
Hemicellulose 23-32
Cellulose 38-50
What is the purest form of cellulose known in nature?
Cotton
the polysaccharide fraction of the woody element comprising about 60-70%
Holocellulose
Man can digest starch (a polysaccharide) but not _______ which animals can
digest because of cellulose enzymes present in their guts or stomachs.
Cellulose
long chain of glucose units that polymerize into microfibrils.
Cellulose
matrix substance of the cell wall composed of two types of sugar molecules: xylans and glucomannans.
Hemicellulose
made of intractable material which acts as the cementing substance of wood
Lignin
deters insect and fungal attack and functions as a water barrier; a complex, 3- dimensional substance;
Lignin
the major chemical component of wood fibers; composed of long chains (10,000 + ) of glucose sugar molecules;
Cellulose
“coat” the cellulose chains and help the lignin bind to the cellulose; made up of sugars (glucose)
Hemicellulose
A newly formed wood cell is encased in a thin, membrane-like and pectin-rich wall called a
Primary wall
made up of microfibrils that are dispersed in a loose, irregular interwoven pattern
Primary wall
angle of orientation becomes successively smaller from the inner to the outer parts
Primary wall
intercellular material extending between the cell walls of adjacent wood cells
True middle lamella
refers to the true middle lamella and the primary cell walls of two adjacent wood
cells
Compound middle lamella
non-structural constituents of wood composed of low molecular weight organic compounds
EXTRACTIVES
Composed only 10% in trees but are diverse and extracted through solvents
EXTRACTIVES
Most wood extractives are ______ and only a little part is water-soluble
lipophilic
3 main groups of extractives
- Aliphatic compounds
- Terpenes
- Phenolic compounds
What is the importance of learning the composition of wood?
It will let us know how we can utilize wood effectively and efficiently.
the first clearly visible layer of the cell wall and is located between the plasma membrane and the middle lamella or, in some cells, between the secondary wall and the middle lamella.
Primary cell wall
Plant cells stop growing when the primary cell wall become ______, which may be due to a change in their composition.
Rigid
plant cells create channels that cross the cell walls and allow direct communication between adjacent cytoplasms these channels are called
plasmodesmata.
Plasmodesmata are usually concentrated in.
primary pit fields
T/F. Cells with primary cell wall are usually metabolically active and the cells that develop secondary cell walls usually
have thin primary cell wall.
TRUE
It is a linear polysaccharide formed by glucose monomers linked by β(1-4) bonds. The formula is (C6H10O5)n, where n can be greater to 500 per polysaccharide chain.
Cellulose
T/F. The strength of cellulose fibers is similar to that of steel and the bonds between cellulose molecules by hydrogen bonds make the cellulose microfibrills have crystalline properties in some regions, while the rest acquires paracrystalline properties.
True
It is synthetized in the Golgi apparatus and is transported to the plasma membrane in vesicles, where it is released by exocytosis.
Hemicellulose
the most frequent molecule of hemicellulose.
Xyloglucan
they coat the cellulose microfibrils, helping to the cohesion to form
cellulose fibers.
Synthesized hemicellulose molecules
It form a very diverse group of acidic polysaccharides synthetized in the Golgi
apparatus and secreted into the cell wall.
Pectins
They seem the main ones responsible for the formation of pores that allow the diffusion of small molecules through the primary wall.
Pectins
They are usually rich in proline, hydroxyproline and glycine, amino acids that are found in much repeated sequences found in the cell wall.
Glycoproteins
a substance that is deposited between the plasma membrane and the cell wall; then, it cannot be considered srictly as a component of the primary cell wall.
Callose
It also appears in other places with less clear functions, such as in the pollen tubes or in the cell plate during
cytokinesis.
Callose
This layer, which can be very thick, prevents the loss of water and protects against pathogens.
Cuticle
cells that have the mission of support and those conductors that are part of the xylem develop an additional wall layer called
Secondary cell wall
Once the cell wall is synthetized, the cells die by _______.
Opoptosis
T/F. The proportion of cellulose in the secondary wall is lower than that in the primary wall and it also has hemicellulose in lower proportion.
False, cellulose in 2ndary cell wall is higher
What is the typical substance of the secondary cell wall?
Lignin
They are the interruptions or channels in the entire cell
Pits
What membrane separates the two aligned pits of neighboring cells; this membrane is formed by the middle lamella and the primary walls of the two cells.
Pit membrane
natural products extraneous to a lignocellulose cell wall. They are present within a cell wall but are not chemically attached to it.
Wood extractives
What are the functions of extractives?
to conserve energy in the tree metabolism, and protect against microbial attacks such as fungi, and/or insects.
Effects of extractives on wood
Color
Smell
Hygroscopy
Natural durability
Dimensional stability
acoustic properties
synthesized by the epithelial cells (specialized tissue of the parenchyma), which line the resin canals. They’re responsible for the aromas, flavors, and even colors associated with various types of vegetation.
Terpenes
It protects plants and wood against pathogens such as molds, fungi, and bacteria and can attract pollinating insects or repel herbivores and serves as as resistance to diseases and attacks by microorganisms, and creation
of odor (nerolidol, farnesol, cedrol).
Terpenes
also referred to isoprenoids, are a vast group of naturally occurring compounds with medicinal potencies. (anti cancer compounds)
Terpenoids
They allow the use of hydrocarbons as fuel, such as methane in Bunsen burners and as liquefied natural gas (LNG), and acetylene in welding.
Aliphatic compounds
also known as non-aromatic compounds and are flammable.
Aliphatic compounds
compounds play a preventive role against cancer and heart problems. They also have a protective effect against ultraviolet rays, pathogens, herbivores, and lipids protect against oxidation of the cell membrane.
Aromatic Phenolic Compounds
What is the best-known phenolic acid?
Salicylic acid
found in the knots
f soft wood trees, mainly in the form of hydroxymatairesinol.
Lignans
some of the important phenolic compounds originating from
plant families like Vitaceae, Leguminaceae, Gnetaceae, and Dipterocarpaceae it has antioxidant properties, antifungals, and pharmacological and therapeutic uses.
Stilbenes
What is the best-known stilbene?
Reveratrol
plant-derived antinutrients because they can precipitate proteins, inhibit digestive enzymes, and reduce vitamin and mineral utilization.
Tannins
Different colors, textures, and durability of leathers were achieved by using different formulations of plant tannins referred to as
Tanning liqueurs
