Cells

All living things are made up of one or more cells

Cells are the basic units of life

Unicellular organism

Multicellular organism

MoleculesDNA molecules

Atoms

Organ systems

Cells

nerve cell

Tissuesleaf tissues

cardiactissue

Organismstree human

Organs

leaf

stem

brain

heart

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Most cells are between 10 and 100 microns

Cells = 10,000 to 100,000 times smaller than us

Atoms = 100,000 to 1,000,000 times smaller than cells

Every cell has:

Cell membrane

layer that surrounds the cell

CytoplasmCytoplasm semi-fluid substance inside the cell

Organelles small structures or compartments inside the cell

•Selectively – permeable: only some substances can pass through

Cell Membrane

•Made of a bi-layer of phospholipids embedded with proteins

•Controls what enters and leaves the cell

•Protects the cell from the environment

•Maintains an internal environment different than that outside the cell.

Functions:

Characteristics:

Some proteins act as channels through which certain molecules can pass

Phospholipid bilayer

Fluid mosaic model of the cell membrane:The phospholipids can flow around each other in most parts of the cell membrane

Organelles are divided into two groups:

• Membranous– Nucleus– Endoplasmic reticulum– Golgi apparatus– Vesicles, vacuoles– Lysosomes– Mitochondria– Chloroplasts

• Non Membranous:– Ribosomes– Cytoskeleton

(microtubules, filaments)

– Centrioles– Cilia and flagella

The nucleusMembranous Organelles

Functions:•Controls the activities of the cell•Stores hereditary material (DNA) that is passed on to the next generation

Parts of the Nucleus:Nuclear envelope: • double membrane • separates the nucleoplasm from the cytoplasm• has nuclear pores (openings) that control what

leaves and enters the nucleus

• Chromatin – long, threadlike form of chromosomes– Made of DNA and proteins wound together

• Carries genetic information• Contains the instructions for the cell activities

• Nucleolus: • dark region of chromatin • Site of ribosome production

Parts of the Nucleus:

Electron micrograph of a cell

• Sets of membranes connected to nuclear and plasma membranes

Functions:• Site of synthesis of

organic molecules (esp. proteins)

• Transport of materials around the cytoplasm

Endoplasmic reticulum

Two types:• Rough ER –

ribosomes attached• Smooth ER – no

ribosomes attached

Endoplasmic reticulum

Ribosomes: Structures made of RNA found on rough ER and in cytoplasm

Function:Site of protein synthesis

Stack of membranes that package newly-synthesized molecules [from ER] and distributes to other parts of cell or out of cell 

Golgi apparatus:

Vesicle: membrane bound sac used for transportation of molecules into and out of a cell

Vacuole:Membrane

bound sac used for storage

-enzymes

-water

-starch

-wastes

-lipids

Specialized vesicle containing hydrolytic enzymes to digest large molecules

Usually double walled to protect cell

Important part of programmed cell death called apoptosis

Lysosomes:

Intracellular conversion: Information and products flow from :Nuclear membrane ER Golgi Vesicle Plasma membrane

Getting molecules out:

Vesicles carrying products of the cell fuse with the cell membrane

Mitochondria:

Function:

site of aerobic respiration (breaking down of food molecules to release energy)

Also called the “powerhouse” of the cell

Structure of a Mitochondria:

Chloroplasts:

Function:

site of photosynthesis (process in which light energy is used to make food)

Found in plants, algae and some protists

Structure of Chloroplast:

•Provides internal structural support and allows the cell and organelles to move

•Includes protein filaments (rods) and microtubules (small hollow tubes)

CytoskeletonNon-membranous

Two structures found close to the nucleus at right angles to each otherOrganizes the chromosomes during cell divisionNot found in plant cells 

Centrioles: Non-membranous

Used to move fluids across the cell surface or move the entire cell

Cilia and flagella:

Cilia are short and cover more of the cell membrane

Flagella are long whip-like structures

Plasma membrane or cell membrane

Cytoplasm

Organelles

Membranous Organelles: Non-membranous Organelles:

What are the three parts all cells have?

What are the two groups of organelles?

Name the Non-membranous Organelles:

Name the Membranous Organelles:

NucleusEndoplasmic reticulumGolgi apparatusVesicles, vacuolesLysosomesMitochondriaChloroplasts

RibosomesCytoskeleton (microtubules, filaments)CentriolesCilia and flagella

CellularOrganelles

vacuole

centrioles

mitochondrium

Rough ER

Smooth ER

lysosomes

Golgi

Nucleus

There are three large groups of living organisms called Domains

Bacteria

Archaea

Eukarya Animals

Plants

Protists

Fungi

Domains

Kingdoms

There are three domains of living organisms

Bacteria

Archaea

EukaryaAnimals

Plants

Protists

Fungi

Prokaryotic cells

Eukaryotic cells

They are differentiated by their cell type, organelles and biochemistry

Prokaryotic vs. Eukaryotic Cells

Prokaryotic (bacteria)

• No nucleus- DNA in cytoplasm (nucleoid)

• Few organelles (cell membrane, ribosomes, flagella

• Small [same size of organelles; 1 – 10 μm ]

• Unicellular• Cell wall

Eukaryotic

• Nucleus – DNA contained within a membrane

• Membranous and non membranous Organelles

• Large (10 – 100 μm)• Can be unicellular or

multicellular• Some with cell walls,

some without

Prokaryotic & Eukaryotic Cells

Eukaryotic cellProkaryotic cell

The four kingdoms of Eukarya(Cells contain nucleus)

Protista Fungi

Plantae Animalia

Kingdom Plantae

• Multicellular

• Autotrophic (chloroplasts)

• Cell wall (cellulose)

Domain Eukaryota

Kingdom Animalia

Multicellular (cells are held together by collagen)

Heterotrophic

No cell wall

Domain Eukaryota

Domain Eukaryota

Kingdom Fungi

Multicellular

Multinucleated (several nuclei)

Cell wall (Chitin)

Heterotrophic

Spores used for reproduction

Kingdom Protista

Artificial Group

Unicellular, Colonial or multicellular

Auto/Heterotrophic

Variable cell walls (silica, cellulose, chitin, no cell wall)

Domain Eukaryota