Cell Structure and Function: Key Organelles and Theories

The Cell Theory

all living things are made of cells, All cells came from pre-existing cells, The cell is the smallest functional unit (basic building block) of living things

An organelle

An organelle is a specific structure that carries out a specific function

Prokaryotic Cells

Very small and do not contain membrane bound organelles (can't see them with a light microscope).

Example: Bacteria

Eukaryotic Cells

Larger; contain membrane bound

organelles.

Example: Plant and Animal Cells

Cell Membrane

(Plants and Animals)

Separates and protects the cell from its surroundings; Regulates what enters/exits the cell (selectively permeable).

Cells need: energy, nutrients, water, chemicals, etc.

Cell Wall

(Plants)

Surrounds cell membrane; Strong and rigid; Provides support to cell.

Cytoplasm / Cytosol

(Plants and Animals)

Gelatinous (jelly-like) substance; Carries out chemical reactions (cell division); Supports organelles.

Nucleus

(Plants and Animals)

Controls the cell's activities; Contains DNA; Surrounded by nuclear membrane/envelope

with nuclear pores.

Nucleolus

(Plants and Animals)

Produces ribosomes.

Nucleoplasm

(Plants and Animals)

Gelatinous (jelly-like substance; Contains DNA (chromatin).

Rough Endoplasmic Reticulum

(Plants and Animals)

Processes and transports proteins; Studded with ribosomes; Ribosomes carry out protein synthesis.

Smooth Endoplasmic Reticulum

(Plants and Animals)

Makes lipids and steroids; Carbohydrate metabolism; Breaks down drugs and toxins (detoxification) in the liver; Storage & release of calcium (for muscle movement).

Ribosomes

(Plants and Animals)

Builds proteins; Found on rough endoplasmic reticulum or free-floating in cytosol.

Golgi Body/Apparatus

(Plants and Animals)

Modifies, stores and transports proteins from the RER and substances like fats from the SER.

Collect and process materials to be removed from the cell. Makes and secretes mucus.

Vacuoles

(Plants and Animals)

Storage of macromolecules, stores harmful substances; Animal cells have lots of small vacuoles and plant cells have one large vacuole; keeps plants firm by pressing against cell wall.

Vesicles

(Plants and Animals)

For transport of substances.

Vacuoles

(Plants and Animals)

Stores water

Full of water = high turgor pressure = plump cell = firm stems and leaves

Lysosomes

(Animals and Rarely Plants)

"Clean up crew"

Contains digestive enzymes:

Digestion (breaks down food into particles the rest of the body can use)

Fighting disease (in white blood cells)

Recycling cell components

Cell death

Mitochondria

(Plants and Animals)

Site of cellular respiration;

Breaks down glucose to produce ATP (energy); known as the "powerhouse of the cell".

Chloroplasts

(Plants)

Site of photosynthesis; Uses solar energy and carbon dioxide to produce glucose.

Cytoskeleton

(Animals and Plants)

Network of fibers; Provides support and structure; Allows movement in cell.