2.2

With more advanced microscopes, scientists discovered that all cells can be grouped into two types: prokaryotic cells eukaryotic cells Cell Types

Prokaryotes: NO NUCLEUS! 1 st cells to evolve No Nucleus! The hereditary information (circular DNA) is contained within the cytoplasm. Examples: Archae and Bacteria

The genetic material in a prokaryotic cell is NOT surrounded by a membrane bound nucleus.

Eukaryotes Evolved from prokaryotes Organisms whose cells have a nucleus. Hereditary information (Linear DNA) is contained within the nucleus Examples: –Animals –Plants –Protists –Fungi –“You” have Eukaryotic cells.

A cell without a membrane-bound nucleus is a prokaryotic cell. A eukaryotic cell has a membrane-bound nucleus and many other specialized organelles. Unicellular Organisms (cont.)

Can you identify the two organelles that are only found in the plant cell?

-Surrounds all cells – In a plant cell, it lies beneath the cell wall – In animal cells, it is the outer boundary (made of cholesterol) – Serves as a gateway which helps to control materials going in and out of the cell It’s like the border of a city!

Found in both plant and animal cells Centrally located in cell The nucleus acts as the “brain” of the cell, controls all the activities of the cell and contains genetic information stored in DNA. It’s like the Mayor’s Office in City Hall!

In most cells, the nucleus is the largest organelle. Nucleus (cont.) EM Research Services, Newcastle University

DNA in the nucleus is organized into structures called chromosomes. The nucleolus is also contained in the nucleus and makes ribosomes, organelles involved in the production of proteins. The nuclear envelope is a two-membrane structure that surrounds the nucleus. Nucleus (cont.)

Found in both plant and animal cells Network of tubes that transports materials throughout the cell Two types – Smooth (no ribosomes) – Rough (covered with ribosomes) It’s like a city’s subway!

Found in both plant and animal cells Can be attached to the ER Membrane or floating free in the cytoplasm The smallest organelles Function: Synthesis- Produce proteins and pass them to the interior of the ER. It’s like the brick yard that supplies a city with bricks!

Found in both plant and animal cells Powerhouse of the cell Breaks down sugar molecules to release energy Function: Respiration- Releasing energy stored in food food is “burned” (combined with oxygen) to produce energy for the cell in the form of ATP It’s like a city’s power plant!

It’s like a city’s warehouses, water towers and landfills! Fluid-filled sacs found in both plant and animal cells – In plant cells: very few and very large – In animal cells: many little ones Store food, water and waste

Only found surrounding plant, fungal and bacterial cells A cell wall is a stiff structure outside the cell membrane that protects a cell from attack by viruses and other harmful organisms.cell wall Made of cellulose- a tough, yet flexible material Provides support, structure, and protection for the cell It’s like the wall that surrounds a medieval city!

Found in plant cells only Green in color due to a pigment called chlorophyll They capture energy from the sun and use it to produce food (sugar) for the cell during photosynthesis It’s like the solar panels on a city’s buildings!

Found in both plant and animal cells Coiled structures of DNA & protein; found in the nucleus City planning office that works with the Mayor’s office

Makes Ribosomes Found in both plant and animal cells It’s like a Factory!

Lysosomes Found in both plant and animal cells Function: contains digestive enzymes that digests old cell parts. They are the cell’s clean-up crew. They have their own membrane to protect the cell from their chemicals. It’s like a city’s street sweeper!

Golgi Apparatus Found in both plant and animal cells Looks like a flattened stack of membranes (or pancakes!) They receive proteins from the ER and package them into vesicles. Vesicles are organelles that transport substances from one area of a cell to another area of a cell. It’s like a city’s Post Office!

Cytoplasm Surrounds and protects cell organelles Found in both plant and animal cells Clear, thick, jelly-like material Located beneath cell membrane Also contains the cell’s cytoskeleton- a network of threadlike proteins that give a cell its shape It’s like the air in a city!

Plant CellAnimal Cell

ribosomes Golgi bodies or ER Mitochondria chloroplasts Lysosomes nucleus Cell wall or cell membrane vacuoles