CHAPTER 3 CELLS 3.2 Cell Organelles

KEY CONCEPT Eukaryotic cells share many similarities.

Cells have an internal structure. The cytoskeleton has many functions supports and shapes cell helps position and transport organelles provides strength assists in cell division aids in cell movement

Three main types of fibers make up the cytoskeleton. Microtubules – long hollow tubes  Give cell shape  Act as “tracks” for the movement of organelles Intermediate filaments  Smaller then Microtubules  Give cell strength Microfilaments  Smallest of 3  Tiny threads that help cell move and divide  Recall that Cytoplasm also helps shape the cell

Cytoplasm aids in structure The fluid portion mostly water is called cytosol Gives structure to cells by exerting pressure on the cell walls of plants

Several organelles are involved in making and processing proteins. Much of the cell is dedicated to making proteins Recall proteins are made from 20 amino acids Proteins are very powerful because of their almost limitless variety of shapes and interactions Proteins carry out many critical functions Need to be made correctly

Nucleus Control center “brain of cell” Stores genetic information - DNA.

Nucleolus Dark spots in nucleus  Ribosomes are made here

Endoplasmic reticulum Interconnected network of thin folded membranes Transports materials throughout the cell Produce lipids and proteins

Two Types of ER Rough ER Contains ribosomes Makes and transports proteins Smooth ER NO ribosomes Makes and transports lipids

Golgi apparatus Closely layered stacks of membrane enclosed spaces Looks like a stack of pancakes Proteins are sorted, processed, and delivered Packaging and distribution center of the cell

Ribosomes Ribosomes link amino acids to form proteins. Proteins synthesis – they’re made here!

Vesicles Vesicles are membrane-bound sacs that hold and transport materials.

Other organelles have various functions. Mitochondria Supply energy to the cell. Via respiration – glucose + oxygen = energy

Vacuoles Fluid-filled sacs that hold materials.

Lysosomes Break down worn out cell parts Contain enzymes to digest material (bacteria).

Centrioles Centrosomes small regions in cytoplasm Tubes found in the centrosomes. Centrioles help divide DNA Centrioles form cilia and flagella

Plant cells differ slightly from animal cells. Plant cells have : Cell walls Chloroplasts Central vacuole

Cell wall Protects, supports and shapes cell Made of cellulose – (what is that?)

Chloroplasts Chloroplasts convert solar energy to chemical energy.  How? Photosynthesis Magnified

Food for thought! Chloroplast/Mitochondria Both have their own DNA and ribosomes Were they once separate organisms???????