THE PLANT CELL: Structures & Functions Flashcards
Biological process that includes capture of light energy and its transformation into chemical energy of organic molecules that are manufactured from carbon dioxide and water
PHOTOSYNTHESIS
Cellular process in which energy of organic molecules is released for biological work
CELLULAR RESPIRATION
Plants form new individuals by asexual or sexual reproduction
Reproduction
The 2 people that invented the first compound microscope.
Hans and Zacharias Janssen
Englishman was the first to use the term “cell” based on his observations of the cork sliver under the microscope; these are included in his illustrated book Micrographia.
Robert Hooke
Dutch microscopist made his own microscopes (ca. 500) and observed various types of microscopic organisms;
Antonie van Leeuwenhoek
he is known as the “Father Of Microscopy and Microbiology”
Antonie van Leeuwenhoek
german microscopist , found that plants were composed of cells;
Matthias Schleiden
found that animals were composed of cells.
Theodore Schwann
German concluded that cells can only come from preexisting cells
Rudolf Virchow
The cell theory states:
All organisms are composed of one or more cells.
The cell is the basic unit of structure and function in organisms.
All cells come only from other cells.
General Cell Types
Prokaryotic cells - Bacteria and Archaea
Eukaryotic cells - Protists, Fungi, Plants, Animals
Cell structure is diverse but all cells share common characteristics such as (4)
- Genetic material – in a nucleoid or nucleus
- Cytoplasm – a semifluid matrix
- Plasma membrane – a phospholipid bilayer
- Ribosome for protein synthesis
Evolution of the eukaryotic cell
endosymbiont theory
Heterotrophic bacteria became mitochondria.
Cyanobacteria became chloroplasts.
Host cell was a large prokaryotic cell.
Endosymbiotic hypothesis
Mitochondria and chloroplasts
Similar to bacteria in both size and structure.
Bounded by a double membrane – the outer membrane may represent the engulfing vesicle, and the inner membrane from the prokaryote.
Each contain a circular DNA and divide by splitting
Have their own ribosomes and do produce some proteins like the prokaryotes
Have RNA base sequence suggesting a prokaryotic origin.
Evidences for the endosymbiotic hypothesis
With a membrane-bound nucleus
With membrane-bound organelles
Cellular functions compartmentalize within organelles and the endomembrane system
possess a cytoskeleton for support and to maintain cellular structure
Eukaryotic Cells
Three structures define a plant cell:
Cellulosic Cell Wall
Plastids
Large Central Vacuole
First wall laid down
Outer wall
Surrounds growing cells, meristematic cells, Cells in succulent tissues
Composed of Cellulose, Hemicellulose: alkali-soluble portion of the cell wall, Pectin: water soluble, Glycoprotein
Primary Wall
Inner wall
Surrounds cells of secondary tissues
Wood, cork
Composed of
Cellulose
Hemicellulose
Pectin
Lignin/suberin
Secondary Wall
Long chain of ß glucose monomers
Cellulose molecule
all higher plants except grass have how much percentage of pectin in their walls
30-35%
grass plants have how much pectin percentage
10%
*Dissolves and thickens in water
*May make you feel satiated
*May lower cholesterol
*Includes pectins, gums and mucilages
soluble fiber
Sources of soluble fiber
legumes (beans & peas), oatmeal, oat bran, barely, citrus
*Woody/structural parts of plants
*Speeds passage of foods through digestive track
*Reduces risk of colon cancer
*Includes cellulose, some forms of hemicellulose, lignin
insoluble fiber
Sources of insoluble fiber
fruits & vegetable skins, wheat bran, whole grain cereals
Living surface membrane of a cell
Acts as a selective barrier to passage of materials into and out of the cell
Plasma Membrane
Not uniformly distributed
Some are organized as part of lipid rafts or microdomains
Movement/occurrence under certain conditions or restrictions
Heterogenous
proteins in cell membranes
all materials to pass through the cell membrane, breaks in the cell walls to connect plasma membrane
plasmodesmata
have raft and non-raft portions in the cell membrane
Lipids
portions with lipid and proteins
non-raft
clustering of specific lipids and proteins “ordered” clustering or domains microdomains move along the surface
lipid rafts
organized into sets in the cell membrane immune adhesion, viral, synaptic, chemotaxis, protein clusters, but there are _____ which are also not part of lipid rafts
proteins
are a dynamic assembly of proteins and specialised membrane microdomains that are free-floating in the fluid-mosaic lipid bilayer
Lipid Rafts
are composed of the lipid bilayer, cholesterols and sphingolipids. These three components self-assemble and forms microdomains that are highly ordered. The lipid components of these structures are rich in long hydrocarbon chain with hydroxylated ceramide backbones (Simons & Sampaio
Lipid Rafts
an anchor to link cell membranes and protein. These proteins function as enzymes, adhesion molecules, complement regulators, or co-receptors in signal transduction pathways
Glycosylphosphatidylinositol (GPI)
the cell membrane is heterogenous and patchy due to nature of proteins which diffuse or remain attached to its neighbors
Fluid mosaic model