Plant Cells

Chapter 3

Major Learning Objectives

Contrast prokaryotic and eukaryotic cells

Describe the functions of 10 parts of a plant cell

Summarize the similarities and differences between plant cells and animal cells

Explain the basic structure of the fluid mosaic model of a membrane

Define the processes that are important to the cell: diffusion, osmosis, facilitated diffusion, and active transport

LEARNING OBJECTIVE 1

Contrast prokaryotic and eukaryotic

cells

KEY TERMS

CELL THEORY

Theory that the cell is the basic unit of

life, of which all living things are

composed, and that all cells are derived

from preexisting cells

Methods to Study Cells

Light and Electron Microscopes

Cells

Two fundamentally different types of

cells: prokaryotic and eukaryotic

KEY TERMS

EUKARYOTIC CELL

A cell that posses a nucleus and other

membrane-bound organelles

PROKARYOTIC CELL

A cell that lacks nuclei and other

membrane-bound organelles (archaea

and bacteria)

LEARNING OBJECTIVE 2

Describe the functions of the following

10 parts of a plant cell: plasma

membrane, nucleus, chloroplasts,

mitochondria, ribosomes,

endoplasmic reticulum, Golgi

apparatus, vacuole, cytoskeleton, and

cell wall

“Typical” Plant Cell

KEY TERMS

PLASMA MEMBRANE

Living surface membrane of a cell

Acts as a selective barrier to passage of

materials into and out of the cell

NUCLEUS

A cellular organelle that contains DNA

and serves as control center of the cell

The

Nucleus

KEY TERMS

PLASTID

A group of membrane-bound organelles

occurring in photosynthetic eukaryotic

cells

Chloroplasts, leucoplasts, and

chromoplasts

Chloroplasts

Sites of photosynthesis

The Chloroplast

KEY TERMS

MITOCHONDRION

An intracellular organelle associated with

cellular respiration (in which chemical

energy in fuel molecules is transferred to

ATP)

RIBOSOME

A cellular organelle; site of protein

synthesis

The Mitochondrion

ORIGINAL

PROKARYOTIC

HOST CELL

EUKARYOTIC CELLS:

ANIMALS, FUNGI,

SOME PROTISTS

Endoplasmic reticulum

and nuclear envelope

form from the plasma

membrane invaginations

(This idea is not part of

the hypothesis of serial

endosymbiosis)

EUKARYOTIC

CELLS: PLANTS,

SOME PROTISTS

…become

chloroplasts

Photosynthetic

bacteria...

Aerobic bacteria

become mitochondria

DNA

Aerobic bacteria Multiple invaginations

of the plasma membrane

p. 52

KEY TERMS

ENDOPLASMIC RETICULUM (ER)

An organelle composed of an

interconnected network of internal

membranes within eukaryotic cells

Site of enzymatic activity

Synthesizes membranes such as

nuclear envelope

Rough ER is associated with ribosomes;

smooth ER lacks ribosomes

The ER

KEY TERMS

GOLGI BODY

An organelle composed of a stack of

flattened membranous sacs

Modifies, packages, and sorts proteins

that will be secreted or sent to the

plasma membrane or other organelles

The Golgi Body

KEY TERMS

VACUOLE

A large, fluid-filled, membrane-bound

sac within the cytoplasm that contains a

solution of salts, ions, pigments, and

waste materials

The Vacuole

KEY TERMS

CYTOSKELETON

Composed of microtubules and

microfilaments

Maintains the cell’s shape

Involved in cellular movement

KEY TERMS

CELL WALL

Comparatively rigid supporting wall

exterior to the plasma membrane in

plants, fungi, prokaryotes, certain

protists

Cellulose

Fibers in a Cell

Wall

Layers of the Plant Cell Wall

Plasmodesmata

LEARNING OBJECTIVE 3

Summarize the similarities and

differences between plant cells and

animal cells

Comparing Plant and Animal

Cells 1

Structures in common

Plasma membrane

Nucleus mitochondria

Ribosomes

ER

Golgi apparatus

Cytoskeleton

Comparing Plant and Animal

Cells 2

Found in plant cells only

Plastids

Cell walls

Large vacuoles

Found in animal cells only

Centrioles

Lysosomes

LEARNING OBJECTIVE 4

Explain the basic structure of the fluid

mosaic model of a membrane

KEY TERMS

FLUID MOSAIC MODEL

Current model for the structure of the

plasma membrane and other cell

membranes in which protein molecules

“float” in a fluid phospholipid bilayer

Fluid Mosaic Model

Explains membrane structure

Each membrane is composed of a

phospholipid bilayer in which varying

proteins are embedded

Phospholipid Bilayer

Nonpolar, hydrophobic fatty acid

chains of phospholipids project into

interior of the double-layered

membrane

Polar, hydrophobic heads located on

two surfaces of the double-layered

membrane

Membrane Structure

LEARNING OBJECTIVE 5

Define the following processes that

are important to the cell: diffusion,

osmosis, facilitated diffusion, and

active transport

KEY TERMS

DIFFUSION

Net movement of particles (atoms,

molecules, or ions) along a

concentration gradient from an area of

higher concentration to an area of lower

concentration

Diffusion

KEY TERMS

OSMOSIS

Net movement of water (principle solvent

in biological systems) by diffusion

through a selectively permeable

membrane

Osmotic Terminology

Turgor

Pressure

Facilitated Diffusion

A carrier protein helps move a

material across a membrane in the

direction of the concentration

gradient, from high to low

concentration

Active Transport

Energy is expended to move a

material against the concentration

gradient, from low to high

concentration

Diffusion, Facilitated Diffusion, and

Active Transport