Plants & Resources Ch. 2

What is a cell?

The smallest unit that meets all the characteristics of living things

What structures do all cells contain?

Plasma membrane, cytoplasm/cytosol, organelles, and genetic material

What is the plasma membrane?

A lipid bilayer that creates a boundary between the cell and its environment

What is cytoplasm (cytosol)?

The fluid and dissolved material within the cell

What are organelles?

Chambers or structures within a cell that perform specific functions

What is genetic material?

DNA or RNA that contains instructions for the organism

What is a prokaryotic cell?

A cell with no nucleus and no membrane-bound organelles

What is a eukaryotic cell?

A cell that has a nucleus and membrane-bound organelles

What is the function of the plasma membrane?

Controls what enters and leaves the cell and separates it from the environment

What is the plasma membrane made of?

A phospholipid bilayer with embedded proteins

What are the parts of a phospholipid?

A polar (hydrophilic) head and nonpolar (hydrophobic) tails

How are phospholipids arranged in the membrane?

Hydrophobic tails face inward and hydrophilic heads face outward

What role do proteins play in the plasma membrane?

Act as tunnels, pumps, and transporters for materials

What is the nucleus?

The organelle where genetic material (DNA) is located

What is the function of the nuclear membrane?

Keeps DNA organized and allows passage of proteins and messenger molecules

What special feature does the nuclear membrane have?

Large pores

What are ribosomes?

Structures where proteins are built

Where are ribosomes found?

Free-floating in the cytoplasm or attached to the endomembrane system

What is the endomembrane system?

A system of membranes that includes the nuclear membrane, ER, Golgi apparatus, and vesicles

What is the rough endoplasmic reticulum (RER)?

ER with ribosomes attached; site of protein assembly

What is the smooth endoplasmic reticulum (SER)?

ER without ribosomes; site of lipid production

What are vesicles?

Membrane-bound bubbles that transport materials within the cell

What is the Golgi apparatus?

Modifies, stores, and ships products from the ER (Endoplasmic Reticulum)

What is the function of mitochondria?

Site of aerobic respiration and energy release

Why are mitochondria called the powerhouse of the cell?

They break down carbohydrates to release energy

What structures are found in plant cells but not animal cells?

Chloroplasts, cell wall, and central vacuole

What is the function of chloroplasts?

Carry out photosynthesis

What pigment do chloroplasts contain?

Chlorophyll

What do chloroplasts convert light energy into?

Chemical energy (glucose)

Do plants have mitochondria?

Yes, plants have mitochondria in addition to chloroplasts

What is the cell wall?

A rigid structure outside the plasma membrane that provides protection and support

What is the primary cell wall made of?

Cellulose

What is the secondary cell wall made of?

Lignin

What is plasmodesmata?

Protein tunnels that allow materials to pass between neighboring plant cells

What is the middle lamella?

A carbohydrate layer that holds plant cells together

What is the central vacuole?

A large storage chamber that holds water and dissolved substances

How does the central vacuole support plants?

Provides pressure that keeps the plant upright

Why do plants wilt when dehydrated?

The central vacuole loses water

What are amyloplasts?

Colorless storage vacuoles that store starch

What are chromoplasts?

Vacuoles that contain pigments unrelated to photosynthesis

What must all cells maintain internally?

A stable internal environment

What is membrane permeability?

The ability of the membrane to control what enters and leaves the cell

What is passive transport?

Movement of substances without using cellular energy

What is a concentration gradient?

A difference in concentration between two areas

What is diffusion?

Movement of molecules from high concentration to low concentration

What is equilibrium?

Equal concentration of molecules on both sides of a membrane

What is osmosis?

Diffusion of water across a semi-permeable membrane

What direction does water move during osmosis?

From low solute concentration to high solute concentration

What are aquaporins?

Special channel proteins that allow water to pass through membranes

What is an isotonic solution?

Equal solute concentration on both sides of the membrane

What is a hypertonic solution?

A solution with a higher solute concentration

What is a hypotonic solution?

A solution with a lower solute concentration

What happens to a cell in a hypertonic solution?

Water leaves the cell and it shrinks

What happens to a cell in a hypotonic solution?

Water enters the cell and it swells

Why can animal cells burst in hypotonic solutions?

They lack a cell wall

What is active transport?

Transport that requires cellular energy

What is endocytosis?

Vesicle-mediated transport into the cell

What is phagocytosis?

“Cell eating” that takes in large materials

What is exocytosis?

Vesicle-mediated transport of materials out of the cell

What is the plant body made up of?

Two main systems: the shoot system and the root system

What is the shoot system?

The above-ground portion of the plant

What structures are part of the shoot system?

Stems, leaves, flowers, and fruit

What is the root system?

The below-ground portion of the plant

What are the main functions of the root system?

Anchors the plant and absorbs water and nutrients from the soil