Ch 3.1- Plant Cells

Prokaryotic

Cells lack a nucleus

DNA is contained in a nucleoid region

No organelles

Eukaryotic

Cells contain a nucleus

More complex

Contain cell wall and organelles

Cell wall

Rigid boundary of cells

Not in animal cells

Organelles

Membrane-bound bodies found within eukaryotic cells

Cell size

Between 10 and 100 micrometers

______ cells have faster and more efficient cellular communication due to the increase in surface to volume ratio

Smaller

Plasma Membrane

Semipermeable

Regulates movement of substances in and out of cell

Composed of phospholipids arranged in two layers

______ consists of all living cell components

Cytoplasm

Cytoplasm

Consists of all cellular components between the plasma membrane and the nucleus

Cytosol

Fluid within the cytoplasm containing organelles

Organelles

Membrane-bound structures of various shapes and sized with specialized functions

Nucleus

Control center if the cell and contains DNA

Sends coded messages from DNA to other parts of the cell

Bound by two membranes, constituting the nuclear envelope

Occupy 1/3 of total surface area

Nucleoili

Composed primarily of RNA

Chromatin Strands

Composed of DNA and proteins

Coil and become chromosomes

Ribosomes

Consist of two subunits that are composed of RNA and proteins

Link amino acids to construct complex proteins

Subunits assembled in nucleolus

May occur on outside of rough ER, or in cytoplasm, chloroplasts or other organelles

No bounding membranes

Cellulose

main structural component of cell walls (long chains of glucose monomers)

Hemicellulose

Holds cellulose fibrils together

Pectin

Gives stiffness (like in fruit jellies)

Denatures in high T

Glycoproteins

Proteins with associated sugars

Primary cell wall

Flexible and laid on either side of the middle lamella

Secondary Cell Wall

Produced inside primary walls

Derived from primary walls by thickening and inclusion of lignin

Cellulose microfibrils embedded in lignin for strength

Lignin

Brown color to cell

More brown, more durable

True or False: Fluids and dissolved substances can pass through primary walls of adjacent cells via plasmodesmata

True

Plasmodesmata

Cytoplasmic strands that extend between cells through minute openings

Endoplasmic Reticulum

A network of flattened sacs and tubes forming channels throughout the cytoplasm

Synthesize membranes for other organelles and modifies proteins

Facilitates cellular communication and channeling of materials

Rough ER

Ribosomes distributed on outer surface of Er

Associated with protein synthesis and storage

Smooth ER

Devoid of ribosomes and associated with lipid secretion

Dictysomes

Golgi bodies in animals

Stacks of flattened discs or vesicles

Modify carbs, assemble polysaccharides, and collect them in small vesicles

Contents: Cell wall polysaccharides, floral nectars, and essential oils in herbs

Plastids

Ex: Chloroplasts

Double membrane

Grana is made of thylakoids

Thylakoid membranes contain chlorophyll

Small circular DNA molecule

Encode for production of certain proteins for photosynthesis

First step of photosynthesis

Occur in thylakoid membranes

Stroma

Matrix of enzymes involved in photosynthesis

Chromoplasts

Type of plastid

Synthesize and accumulate carotenoids (yellow, orange, red)

Leucoplasts

Colorless plastids

Amyloplasts

May synthesize starches

Elatoplasts

Oils

Mitochondria

Release energy via cellular respiration

Powerhouse of cell

Bound by two mebranes:

Outer

Inner

Numerous folds in the inner membrane of mitochondria

Cristae

Increases surface area available to enzymes in matrix

Matrix of mitochondria

Fluid within mitochondria

Includes DNA and RNA

Microbodies

Small, spherical bodies distributed throughout the cytoplasm that contain specialized enzymes

Bound by a single membrane

Peroxisomes

Serve in photorespiration

Cytoskeleton

Framework and motion of cell

Network of microtubules and microfilaments

Microtubules

Control addition of cellulose to the cell wall

Involved in the movement of flagella and cilia

Found in spindles in dividing cells

Microfilaments

Role in cytoplasmic streaming

AKA Brownian Movement

Vacuoles

90 % of cell volume may be taken up by central vacuoles

Bounded by vacuolar membranes

Filled with watery fluid (cell sap)

Contains dissolved substances, such as salts, sugars, and water-soluble pigments called anthocyanins (red, blue, purple)

Function: Maintenance of cell pressure and pH, storage of numerous cell metabolites and waste products

Plant Cells:

Cell walls

Cell plate and plasmodesmata

Plastids and vacuoles

Animal Cells

Internal or external skeleton

No cell wall

Plasma membrane is called cell membrane

Divides by pinching into two; no cell plate or plasmodesmata

Centrioles present during cell dividion

No plastids nor vacuoles

Outermost part of living cell

Primary cell wall