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What is the relationship between humans and their environment?

Humans and animals depend on plants to survive

Botany

Plant biology/plant science

Plant Anatomy

Study of internal structure of plants

Plant Physiology

Study of plant function

Plant Taxonomy

Study of describing, naming, classifying organisms

Plant Systemics

-Related field to Plant Taxonomy - but broader

-Study of developing methods for grouping organisms

Plant Geography

Study of how and why plants are distributed where they are

Plant Ecology

Study of the interaction of plants with one another and their environment

Plant Morphology

Study of form and structure of plants

Genetics

-Science of hereditary

-Branches: Plant breeding and Genetic Engineering

-Gregor Mendel

Cell Biology

Science of cell structure and function

Economic Botany and Ethnobotany

Focus on practical uses of plants and plant products

Effects humans have on the environment

-Drained wetlands

-Cleared natural vegetation

-Dumped wastes and pollution

-Used pesticides and herbicides

Ways for humans to reduce environmental impact

-Change agricultural practices

-Render pollutants harmless

-Recycle

-Replace pesticides with biological pest controls

-Conserve water and energy

-Preserve habitats and species

Prokaryotic Cells

-Lack nucleus

-Free floating DNA in nucleoid region mixed with cytoplasm

-No organelles

-No nuclear membrane surrounding DNA

-Examples: Bacteria and Archaea

Eukaryotic Cells

-Contains nucleus bounded by Nuclear membrane

-Cell walls

-Membrane-bound organelles

-Examples: Plants and animals

Protoplasm

-Surrounds cell wall

-Consists of all living components of a cell

Cell Wall

-Supports and protects the cell

-Contains Cellulose: main structural component of cell walls

-Contain matrix of:
-Hemicellulose: holds cellulose fibrils
together
-Pectin: gives stiffness
-Glycoproteins: proteins with associated
sugars; keep cells tight

-Primary wall, Secondary wall, Middle lamella

Primary Cell Wall

-Thin and flexible

-Laid down on either side of middle lamella

-Made of cellulose: main structural component

Secondary Cell Wall

-Produced between the primary cell wall and plasma membrane

-Cellulose microfibrils embedded in lignin for strength

-Derived from primary wall by thickening and inclusion of lignin

-Lignin makes wall less flexible

-Used to reinforce plant walls

Middle Lamella

-First produced when new cell wall are formed

-Forms in middle of two cells

-Made of Pectin

-Shared by two adjacent cells

Plamsa Membrane

-Bounds all living components of a cell

-Phospholipid bilayer: semipermeable outer boundary of cell

-Regulates movement of
substances into and out of cell

-Composed of phospholipids arranged in two layers with proteins interspersed throughout

-Hydrophilic heads, Hydrophobic tails

-Fluid mosaic model

Cytoplasm

Consists of all cellular components between plasma membrane and nucleus

Cytosol

Fluid within cytoplasm containing organelles

Organelles

-Perform specialized functions in cell

-Various shapes and sizes

-Most are membrane-bound

Nucleus

-Control center of cell

-Contains DNA

-Sends coded messages from DNA to be used in other parts of the cell

-Bounded by Nuclear envelope

Nuclear Envelope

-Surrounds Nucleus

-Composed of two membranes

-Complex pores occupy up to 1/3 of total surface area

-Permit only certain kinds of molecules to pass between nucleus and cytoplasm

Nucleolus (Nucleoli)

-Organelle within nucleus

-Contains RNA and proteins

Chromatin Strands

-Located in nucleus

-Composed of DNA and proteins

-Coil to become chromosomes

Chromosomes

-Located in nucleus

-Condensed DNA

Endoplasmic Reticulum (ER)

-Enclosed space

-Network of flattened sacs and tubes forming channels throughout cytoplasm

-Facilitates cellular communication and channeling of materials

-Synthesizes membranes for other organelles and modifies proteins

-Composed of Rough ER and Smooth ER

Rough ER

-Synthesis, secretion, and storage of proteins

-Ribosomes distributed on outer surface

Smooth ER

-Lipid secretion

-Few, if any, ribosomes

Ribosomes

-Consist of two subunits composed of RNA and proteins

-Link amino acids to construct complex proteins

-Subunits assembled in nucleolus

-No bounding membranes

-May occur on outside of Rough ER, in cytoplasm, chloroplasts, and other organelles

Dictyosomes

-Golgi bodies in animals

-Stacks of flattened discs or vesicles

-Scattered throughout cytoplasm

-Modify carbohydrates attached to proteins that are synthesized and packaged in the ER
-Assemble polysaccharides and collect them in small vesicles
-Vesicles pinched off from margins of dictyosomes
-Vesicles migrate to plasma membrane, fuse with it, and secrete contents to outside of cell
-Contents may include cell wall polysaccharides, floral nectars, and essential oils in herbs

-Collecting, packaging, and delivery centers of cell; "Post office" of cell

Plastids

-Storage and manufacture of carbohydrates

-Chloroplasts are most common

-Bounded by double membrane

-Grana (granum): contain thylakoids
-Thylakoid membranes contain
chlorophyll
- First steps of photosynthesis
occur in thylakoid membranes

-Stroma: matrix of enzymes involved in photosynthesis
-Small circular DNA molecule
-Encodes for production of
certain proteins for
photosynthesis

-Other types: Chromoplasts and Leucoplasts

Chromoplasts

-Type of plastid

-"Chromo" = color

-Synthesize and accumulate carotenoids (yellow, orange, red)

Leucoplasts

-Type of plastid

-Colorless

-Amyloplasts (synthesize starches) and Elaioplasts (synthesize oils)

Mitochondria

-Releases energy produced from cellular respiration

-Bounded by two membranes
-Inward membrane: forms
numerous cristae (folds),
increases surface area
available to enzymes in matrix

-Matrix fluid also contains DNA, RNA, ribosomes, proteins, and dissolved substances

Microbodies

-Small, spherical bodies

-Distributed throughout the cytoplasm

-Contain specialized enzymes

-Bounded by a single membrane

-Peroxisomes: serve in photorespiration and help in detoxification

-Glyoxisomes: aid in conversion of fat to carbohydrates

Cytoskeleton

-Involved in movement within cell and in cell's architecture

-Network of microtubules and microfilaments

Microtubules

-Thin, hollow, tubelike

-Composed of tubulins (proteins)

-Control addition of cellulose to cell wall

-Involved in movement of flagella and cilia

-Found in fibers of spindles and phragmoplasts in dividing cells

Microfilaments

-Role in cytoplasmic streaming
-Cytoplasmic streaming:
movement of cytoplasm in a
circular motion within the cell
for transportation of certain
materials

-Thinner than microtubules

Vacuole

-In mature cells, 90% of volume may be taken up by central vacuoles

-Bounded by vacuolar membranes (tonoplasts)

-Filled with cell-sap (water fluid, slightly to moderately acidic)

-Contains dissolved substances (salts, sugars, organic acids, small proteins)

-Frequently contains anthocyanins (red, blue, purple water-soluble pigments)
-Functions: maintenance of cell pressure and pH, storage of numerous cell metabolites and waste products

Plasmodesmata

-Allows fluids and dissolved substances to pass through primary walls of adjacent cells

-Cytoplasmic strands that extend between cells through minute openings

Differences between plant and animal cells

Plants:
-Cell walls
-Cell plate and plasmodesmata
-Plastids and (Central) vacuoles

Animals:
-Internal or external skeletons
-No cell walls
-Plasma membrane = cell membrane
-Divide by pinching in two
-No cell plate or plasmodesmata
-Centrioles present during cell division
-No plastids of vacuoles

Major Plant Organs

-Roots

-Stems

-Leaves

-Flowers

What are tissues?

-Groups of cells that are similar in structure and function

What is the function of meristems and where are they located?

-Function: growth

-Location: at or near the tips of roots and shoots

Apical Meristem

-Found at tips of roots and shoots

-Roots and shoots increase in length as apical meristem produces new cells

-Primary growth

-Protoderm: outer layer, becomes epidermis

-Ground meristem: cortex and pith

-Procambium: inside layer, divides into vascular tissues (xylem and phloem)

Lateral Meristem

-Produce secondary tissues

-Increase girth of roots and stems

-Secondary growth

-Vascular Cambium: secondary xylem and secondary phloem, function in support and conduction

-Cork Cambium: bark, cork and phelloderm

Intercalary Meristem

-Growth region at base of grass leaves

-Elongation of stem length

-Occur in plants that do NOT have vascular cambium or cork cambium

-Located at nodal region (leaf attachment area)

Simple Tissues

-Composed of one type of cell

-Examples: Parenchyma, Collenchyma, Sclerenchyma

Parenchyma Tissue

-Most abundant tissue in plants

-Contains of parenchyma cells

-Living cytoplasm

-Various shapes

-Loosely packed

-Intercellular space between them

-Thin, pliable walls

-Function in photosynthesis and storage

-Repair of tissues (retain ability to divide after produced)

-Apples and starch vegetables

-Aerenchyma, Chlorenchyma, Transfer cells

Aerenchyma

-Parenchyma tissue

-Extensive connected air spaces

-Usually in aquatic plants- help plants float

Chlorenchyma

-Parenchyma tissue

-Contains chloroplasts that function in photosynthesis

Transfer Cells

-Parenchyma tissue

-Develop irregular extensions of inner wall

-Increase surface area of plasma membrane
-Nectaries of flowers

Collenchyma Tissue

-Contains of collenchyma cells

-Collen = elastic

-Living cytoplasm

-Thick cell walls, uneven thickness

-Pliable and strong

-Suberin in-between cells; gives flexibility

-Function = support

-Present in petiole (stalk) of plant

Sclerenchyma Tissue

-Contains sclerenchyma cells

-Scleren = hard

-Dead at maturity

-Function in mechanical support (standing upright)

-Thick, tough secondary walls

-Normally impregnated with lignin

-Two types
-Sclereids (stone cells):
scattered in tissue, as long as
wide
-Fibers: much longer than wide,
contain lumen (tiny cavities
within fibers), secondary cell
walls

How are parenchyma, collenchyma, and sclerenchyma tissues distinguished from one another?

-Parenchyma and Collenchyma cells are LIVING (no secondary wall)

-Sclerenchyma cells are DEAD (contains secondary wall)

Complex Tissues

-Composed of two or more kinds of cells

-Examples: Vascular tissues (Xylem and Phloem), Epidermis, Periderm

Vascular tissue

-Xylem and Phloem

-Phloem is larger than Xylem

Xylem

-Conduction of water

-Composed primary of dead cells

-Located closer to center

-Types: Vessels, Tracheids, Fibers, Rays

Types of Xylem

-Vessels: long tubes made of vessel elements
-Thick secondary cell walls
-Open at both ends
-Perforation plate between end
walls
-Dead at maturity

-Tracheids: tapered at ends with pairs of pits that allow water pass from cell to cell
-Dead at maturity
-Thick Secondary cell walls
-May have spiral thickenings on
cell walls
-Pits: areas WITHOUT
secondary cell wall

-Fibers: much longer than wide
-Pits are normally absent

-Rays: function in lateral conduction and food storage
-Elongated
-Living
-Composed of long-lived Parenchyma cells

Phloem

-Conduct dissolved food materials produced by photosynthesis throughout plant

-Types: Sieve Tube Members and Companion Cells

Phloem Cell Types

-Sieve Tube Members
-Lack secondary cell walls and
nuclei
-Lay end to end to form sieve
tubes
-Walls have sieve plates with
small pores
-Callose forms callus plug
(prevents leaking of sieve tube
contencts when cell injured)

-Companion Cells
-Aid in conduction of food

Epidermis

-Protective layer one cell-layer thick covering all plant organs

-Composed of parenchyma cells, guard cells of stomata, secretory glands and hairs

-Doesn't contain chloroplasts

-Trichomes: hair-like extensions; extends from epidermis

-Cutin: fatty substance on surface of outer walls that forms cuticle
-Cuticle: prevents water loss by
evaporation

-Resistant to bacteria and other disease organisms

Stomata

-Rigid, living cells

-Open and close to preserve or absorb gasses, water, etc.

Periderm

-Constitutes outer bark

-Form of epidermis

-Found in woody plants

Epidermis vs. Periderm

-In woody plants, the epidermis is sloughed off and replaced by periderm

-Periderm has cork cells that secret suberin

-Suberin makes cork cells waterproof, prevent them from drying out, and protects them from mechanical injury and freezing temps

Simple vs. Compex Tissues

-Simple = one cell type
-Parenchyma, Collenchyma,
Sclerenchyma

-Complex = at least two cell types
-Vascular (xylem and phloem),
epidermis, periderm

Conifers have...

-No vessels

-No companion cells

What types of substances do secretory cells secrete?

-May function individually or as part of a secretory tissue

-Secrete
-Flower nectar
-Citrus oils
-Glandular hair mucilage
-Latex (poison ivy)
-Resins (sticky substance in
Christmas trees

How do roots develop?

-Upon germination, embryo's radicle grows out and develops into primary root

-Radicle may develop into thick taproot with thinner branch roots

OR

-Radicle may be replaced by Fibrous roots

-Adventitious Roots develop from stem or leaf, NOT another root

Tap Roots

-Straight tapering root growing vertically downward and forming the center from which subsidiary rootlets spring

-Dicots

-Examples: carrot, beetroot, parsley

Fibrous Roots

-Large number of fine roos of similar diameter

-Monocots and some dicots

-Examples: wheat, rice, banana, onion

Adventitious Roots

-"not belonging to"

-Develop from stem or leaf, NOT another root (radicle)

-Both dicots and monocots

-Examples: prop roots of corn, rhizomes in ferns, club mosses

Root Cap

-Thimble-shapped mass of parenchyma cells covering each root tip

-Protects tissues from damage as root grows

3 Sub Apical Regions of Root Tip

-Region of Cell Division
-Composed of apical meristem
in center of root tip
-Cells are actively dividing
-3 Primary meristems:
protoderm, ground meristem,
procambium
-Primary growth

-Region of Cell Elongation
-Cells become several times
their original length

-Region of Maturation
-Cells differentiate into various
distinctive cell types
-Root hairs form

Root Hairs

-Epidermal cell extensions with thin cuticle

-Absorb water and minerals

-Adhere tightly to soil particles

-Increase total absorptive surface of root

Root Tip Diagram

3 Primary Meristems

-Protoderm: gives rise to epidermis
-Outer most meristem

-Ground Meristem: gives rise to cortex and pith
-Bulk of plant tissue
-in between protoderm and
procambium

-Procambium: gives rise to primary xylem and primary phloem
-inner most meristem

Epidermis

-Protective layer one cell-layer thick covering all plant organs

-Composed of parenchyma cells, guard cells of stomata, secretory glands and hairs

-Doesn't contain chloroplasts

-Trichomes: hair-like extensions; extends from epidermis

-Cutin: fatty substance on surface of outer walls that forms cuticle
-Cuticle: prevents water loss by
evaporation

-Prevents water loss, regulates gas exchange, absorbs water and mineral nutrients

Cortex

-In between the epidermis (outside) and endodermis (inside)

-Transportation of materials into the central cylinder of root

-May be used for food storage in form of starch

Endodermis

-Inner boundary of cortex

-Consists of a single-layered cylinder of compact cells

-Cell walls impregnated suberin
-Suberin: substance that gives
elasticity, in collenchyma cells
-Except for passage cells

-Normal living cells

-Red bands

-Thickness allows endodermis to push water into xylem

Pericycle

-Outer boundary of vascular cylinder

-Forms lateral (branch) roots and part of vascular cambium

-Regulates the formation of lateral roots by rapidly dividing

Stele (Vascular cylinder)

-Core of tissue inside endodermis

-Xylem and Phloem

Food Storage Root

-Starch and other carbohydrates


-Portion that connects the stem to the root

-Combination of stem and root

-Ex: Sweet Potatoes, Carrots, Beets, Turnips, Radishes

Water Storage Roots

-Pumpkin family, especially in arid regions

-Manroot

Propagative Roots

-Adventitious bud of roots, develop into suckers (aerial suckers)

-Sweet Potatoes, Bunyan tree

Pneumatophores

-In plants with roots growing in water

-Spongy roots that extend above the water's surface and enhance gas exchange between atmosphere and subsurface roots

-Ex: Mangroves

Aerial Roots

-Orchids: Velamen roots, with epidermis several layers thick to
reduce water loss

-Ivies (English ivy, Virginia creeper)
-Aerial roots aid plants in
climbing

Contractile Roots

-Pull plant deeper into the soil

-Ex: Lily bulbs, dandelions

Buttress Roots

-Stability in shallow soil

-Ex: Tropical Trees

Parasitic Roots

-Most have no chlorophyll and dependent on chlorophyll-bearing plants for nutrition

Where do branch roots originate?

-Arise in the pericycle (a cylinder of parenchyma cells lying just inside the endodermis)

How do endodermal cells differ from other types of cells?

-Lack a symplast region

-Are nonselective with regard to solute uptake

-Have a high rate of water transport

-Are completely surrounded by a waxy layer

-Prevent the apoplastic movement of water and ions

-Water must pass through the selectively permeable plasma membrane of the endodermal cells before it reaches the vascular system.

What is the function of the root cap, and from which meristem does it originate?

-Protective cap of live parenchyma cells

-Produced by the apical meristem

-Produces mucilage or mucigel (slimy lubricant)

If you were given cross sections of young roots of a monocot and dicot plants, how could you tell them apart?

Distinguish between a tiny root and a root hair. What is the function of a root hair?

-A root or tiny root is a multicellular organism with multiple tissue layers and other types of roots

-Root hairs absorb water and minerals and adhere tightly to soil particles and are not separate cells