Cells (Prokaryotic & Eukaryotic) w There are two types of cells Prokaryotes and Eukaryotes w Prokaryotes cells that lack membrane-bound organelles. Bacteria are the only organism to have prokaryotic cells. Prokaryote Cell

A prokaryotic cell does not have internal organelles surrounded by a membrane. Most of a prokaryote’s metabolism takes place in the cytoplasm. 1. Ribosomes 2. DNA 3. Plasma membrane 4. Cell wall Click here to return to chapter summary Chapter Assessment

Eukaryotes w Eukaryotes have a higher level of complexity. w Eukaryotic Cells contain organelles that are bound by membranes. w All cells other than bacteria are Eukaryotic cells

This eukaryotic cell from an animal has distinct membrane-bound organelles that allow different parts of the cell to perform different functions. 4. Plasma membrane 1. Nucleus 2. Nucleolus 3. Chromosomes 5. Organelles Chapter Assessment

Components of Cells w Cell Membrane - functions as semi- permeable barrier. Allowing a few molecules across it while fencing the majority of organically produced chemicals inside the cell.

Cell Walls w The Cell Wall is a structure surrounding the cell membrane. w Cell Walls contains cellulose that makes the cells more ridged. w Plants and Plant-liked organisms have cell walls

The Plasma Membrane

Cytoplasm w The cytoplasm is defined as the material between the cell membrane and the nucleus of a cell. w A semi-gel fluid that helps moves substances in a cell.

Organelles w Organelles are formed bodies within the cytoplasm that perform certain functions in a cell. w Examples include: nucleus, ribosomes, endoplasmic reticulum, mitochondria.

Nucleus /Nucleolus/Nuclear membrane or envelope w The nucleus controls the functions of the cells w The nucleus is found only in eukaryotic cells. w The nucleolus found in the nucleus is where nucleotides are constructed, begins the assembly of ribosomes.

Nuclear membrane (con’t) w The nuclear membrane or sometimes called the nuclear envelope is a double-membrane structure.. Numerous pores occur in the envelope, allowing RNA and other chemicals to pass, but not DNA.

Chromosomes w Chromosomes are found in the nucleus. They may appear as “Xs”. w Chromosomes contain the hereditary material of DNA which control all cell activities. w Chromosomes are able to replicate or reproduce.

Centrioles w Play a major role in cell reproduction only found in animal cells. w Generally only seen during cell division w May look like a long cylindrical asterisk in most models

Cytoskeleton w The cytoskeleton is a network of protein filaments that helps the cell to maintain its shape. The cytoskeleton is also involved in movement.

Vacuoles w Vacuoles are usually a storage area and recycling site. w Vacuoles usually appear larger in plant cells than in animal cell. Plant Cell Animal Cell

Ribosomes w Ribosomes are the sites of protein synthesis w Some ribosomes are free floating some are attach to endoplasmic reticulum.

Endoplasmic Reticulum w Rough and Smooth Endoplasmic Reticulum w Rough ER Serves the function of storing and transporting proteins. w Rough ER is so named because of its rough appearance due to the numerous ribosomes that occur along the ER. w Smooth ER contains collections of enzymes that perform tasks such as synthesizing membrane lipids and the detoxifications of drugs. Named because it does not have ribosomes attached to it

Mitochondria w Mitochondria function as the sites of energy production. w The mitochondria has been termed the “powerhouse” of the cell.

Golgi Apparatus w Golgi bodies are flattened stacks of membrane-bound sacs (looks likes pancakes). w They function as a packaging plant, for carbohydrates and proteins.

Lysosomes w Lysosomes are the “disposal units” of cells w Lysosomes function in the extracellular breakdown of materials. w Generally found only in animal cells.

Plastids (Chloroplast, Leucoplast, & Chromoplasts) w Chloroplast - are the sites of photosynthesis in eukaryotes. w They contain chlorophyll, the green pigment necessary for photosynthesis

Leucoplast w Leucoplast- stores starch. w Leucoplast are most likely found in the roots tissue of most plant. Example: potato

Chromoplast w Stores pigments associated with the bright colors of flowers and or fruits.

Cilia & Flagella w Cilia and Flagella are similar except for length, cilia being much shorter (hair- like). Flagella are long whip-like. w Both are responsible for movement. Cilia on a paramecium Flagella on a Euglena