Plant and cell anatomy

apical meristem located at

apex (tip) of root

intercalary (axillary) meristems positioned at

base of leaves and internodes

major tissue systems

dermal, ground, vascular

plasmodesmata

Tubular extensions of the plasma membrane that connect cytoplasm of adjacent cells

continuous cytoplasm between cells forms

symplast

preprophase

between G2 and prophase, refines the preprophase band of microtubules to predict the future division plane

prophase

the preprophase band disappears, chromatin condenses into visible chromosomes, and the mitotic spindle starts to form

Metaphase

Chromosomes line up single-file along the middle of the cell (the metaphase plate) guided by the spindle fibers

anaphase

Sister chromatids pull apart toward opposite ends of the cell

telophase

Two new nuclear envelopes form around the separated chromosome sets as they uncoil back into chromatin

cytokinesis

Unlike animal cells that pinch apart, plant cells divide their cytoplasm by forming a cell plate guided by a structure called the phragmoplast, which uses the site originally marked back in the G2 preprophase stage

vacuoles

membrane enclosed compartments without cytoplasm. They can contain 95% of cell volume and are primarily responsible for the increase in cell volume during growth

Oil body (olesomes)

have a half unit membrane and are important for storage of triglycerides

Glyoxysomes (specialized Peroxisomes)

facilitate the oxidation of fatty acids during seed germination

peroxisome

prevents H2O2 accumulation during photorespiration and other specialized metabolic functions

Mitochondria

Site of respiration. They grow by fission and fusion and have their own DNA and ribosomes

Chloroplasts

Site of photosynthesis. They have 3 membrane systems that are rich in glycosylglycerides rather than phospholipids

Nucleus

Stores genetic material and transcribes it into RNA.

Anchored proteins

Peripheral proteins bound by lipid molecules to the membrane by covalent bonds

Integral proteins

ion channels, aquaporin, receptors, cell wall linkages

phospholipid

2 fatty acids, covalently linked to glycerol, phosphate, and polar head group

key components of a biological membrane

phospholipid bilayer and membrane proteins

key differences between plant and animal cells

cell wall, chloroplast, vacuoles, and plasmodesmata

xylem

water and mineral transport

phloem

photosynthate transport

cytoskeleton composed of

microtubules and microfilaments

symplast

continuous cytoplasm connected by plasmodesmata

Tonoplast (vacuole membrane) transporters

storage of secondary metabolites, sugars, organic acids, pigments, etc

Golgi apparatus

stacks of cisternae that buds from the ER

functions of ER

• provides membrane phospholipids and protein cargo for other parts of Endomembrane System

• protein synthesis and secretion

mitochondria evolved from engulfed

aerobic bacteria

chloroplasts evolved from engulfed

photosynthetic cyanobacteria

cell division occurs in

meristems

endosymbiotic theory

early eukaryotic cells engulfed prokaryotic organisms through endosymbiosis. The engulfed organisms evolved into internal organelles rather than being digested, supported by the fact that these organelles contain their own circular DNA, divide independently, and have double membranes

Bryophytes (Non-vascular)

Developed land-dwelling adaptations such as stomata for gas exchange, specialized structures (oil bodies, elaters), primitive conductive tissues (hydroids/leptoids), and multicellular rhizoids

Ferns (Vascular, Seedless)

Evolved lignified xylem (tracheids), branched phloem, true megaphyll leaves

Seed Plants (Gymnosperms & Angiosperms)

Evolved seeds and pollen grains, bypassing the need for standing water during fertilization

Primary Cell Wall

thin, found in young growing cells

secondary cell wall

deposited after cell enlargement ends
thicker and stronger due to lectin

middle lamella

pectin layer which cements cell wall of two adjoining cells together

membrane proteins make up ___ of the membrane

one half

Fluid Mosaic Model

biological membranes as bilayer of phospholipids in which proteins are embedded