Plant Cells

FLASHBACK
Are plants eukaryotic or prokaryotic?
What does eukaryotic mean?

Golgi vesicles ribosome smooth ER nucleolus nucleus rough ER
Large central vacuole amyloplast
Parts of a Plant Cell cell wall cell membrane
Golgi apparatus chloroplast vacuole membrane raphide crystal druse crystal mitochondrion cytoplasm

Cell Wall
Surrounds the plasma membrane
3 layers
Middle Lamella
Primary Wall
Secondary Wall

Middle Lamella
1 st layer formed
Outer wall of the cell
Shared by adjacent cells and cements them together

Primary Cell Wall
INDSIDE middle lamella
Rigid skeleton of cellulose microfibrils in a gel-like matrix of pectic and cellulose compounds.
Contains everything that is located between plasma membrane and the cuticle

Primary Cell Wall Functions
Structural & mechanical support
Maintain cell shape
Resist turgor pressure
Control rate and direction of growth
Carbohydrate storage
Cell-cell interactions

Secondary Wall
Formed after cell enlargement is completed.
Extremely rigid
Contains lignin- brown phenolic polymer
Present in trees and shrubs

Plasmodesmata
Small passages that penetrate all layers of the cell wall
Pathways for transporting cytoplasmic molecules

Plasma (cell) Membrane
Phospholipid bilayer
Sandwich modelphospholipid layers sandwiched between protein layers
Embedded glycoproteins
Water permeable
Not permeable to molecules and ions by simple diffusion
Gatekeeper for the cell.

Golgi Apparatus
Stack of flattened membrane-bound sacs
Storage, modification, and secretion of proteins and lipids
Lipids and proteins can be used within the cell or destined to leave the cell

Calcium Oxalate Crystals
Located in the central vacuole
Potentially toxic
Raphide crystals-pointy and needle like
Druse crystals-faceted

Mitochondrion
Membrane-bound organelle
“power house” of the cell
Respiration takes place here.

Golgi vesicle
Membrane bound
Buds from Golgi apparatus
Contain proteins
Fuse with membrane and discharge contents in a process called exocytosis

Ribosome
Site of protein synthesis
Composed of small sub unit, large sub unit, and central groove.

Smooth ER
Membrane bound system of folded sacs
Provides a membrane surface where a variety of complex carbohydrates and lipids, including phospholipids are synthesized
Detoxifies toxic substances
Rough ER
Attached ribosomes
ER

Nucleolus
Where rna is synthesized

Membrane bound
Where chromatin is stored
Nucleus

Large Central Vacuole
Large membrane bound sac
Stores water, salts, pigments, and potentially toxic molecules.
Helps maintain rigidity

Others
Amyloplast- a membrane-bound organelle made of layers of starch
Lysosome- membrane-bound organelle containing hydrolytic (digestive) enzymes
Peroxisome- a membrane-bound organelle that contains specific enzymes imported from cytosol (e.g. catalase)

Chloroplast Intro
Membrane bound organelle
Site of photosynthesis

CELL CITY
Take 15

Endosymbiont Theory
Chloroplasts and mitochondria house their own DNA.
It is possible to track lineage through chloroplasts and mitochondria.
Chloroplasts and mitochondria have their own phospholipid membrane.

Endosymbiont Theory
Scientists believe that plant and animal cells acquired chloroplasts and mitochondria through the process of symbiogenesis
Symbiogenesis is acquiring cells or dna from other organisms.
In other words: