Cells The basic unit of all living things. Are made up of “little organs” called organelles.

There are many types of cells.

Cells can be divided into two types: Prokaryotic Eukaryotic

Prokaryotes Bacteria Very small Oldest cells on Earth Very simple: No membrane- bound organelles or nucleus DNA circular found in cytoplasm

Eukaryotes Plant, Animal, Fungus, Protists, etc (ANYTHING living that is not Bacteria) Larger Newer, more recently evolved Have membrane-bound organelles Have membrane bound nucleus that contains DNA in double helix.

The following organelles are found in all cells

Cell membrane -plasma membrane Controls what enters and leaves the cell. Made of phospholipids.

Cell Membrane

Cytoplasm or Cytosol Fluid that surrounds all organelles. Mostly made of water (cells are 75%-90% water)

Where amino acids are made into proteins. Ribosomes Where amino acids are made into proteins. Can be “loose” in the cytoplasm or on the Rough E.R.

Where amino acids are made into proteins. Ribosomes Where amino acids are made into proteins.

Structures for movement Pseudopodia –false foot

Movement Flagella (whip-like structure)

Movement- Cilia (hairlike structures)

Made of protein filaments. Maintains cell shape. Cytoskeleton Made of protein filaments. Maintains cell shape.

Cytoskeleton The cytoskeleton is made up of microtubules and filaments. It is typically not depicted in cell diagrams but is the structural beams and support of the cell

Chromosomes Typically eukaryotic cells (cells with nuclei) have large linear chromosomes and prokaryotic cells (cells without defined nuclei) have smaller circular chromosomes Eukaryote Prokaryote

Prokaryotic Cell

Eukaryotic Cell

Organelles Found in Eukaryotes Organelles found in both plant and animal cells.

Purpose of a Cell Before we get into the jobs of the cell you must first understand the PURPOSE of a cell Oddly enough, it all boils down to proteins. Remember all the functions of proteins Larger Structures: Hair, nails, skin, muscles, eyes, etc. Cellular Structures: Proteins in the membrane, and that make up the organelles Chemical messengers: Hormones Regulating Reactions: Enzymes

Nucleus Control center of the cell. Houses DNA, which is the template for making proteins. “The Brain”

Nuclear envelope The nuclear membrane has many small holes called nuclear pores that allow material to move in and out of the nucleus.

Chromosomes Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA). Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique.

Nucleolus The nucleolus is a round body located inside the nucleus of a eukaryotic cell. It is not surrounded by a membrane, but sits in the nucleus. The nucleolus makes ribosomal subunits from proteins and ribosomal RNA (rRNA).

Endoplasmic Reticulum Smooth E.R.: Assembles/Makes Lipids Rough E.R.: Changes proteins made on ribosomes (where proteins are made)

Golgi Apparatus or Golgi Body Proteins from rough E.R. then go to the Golgi body. Further modify proteins and send to final destination

Vesicles When a cell needs to move a molecule many times, it uses vesicles. Vesicles are cellular organelles that are composed of a lipid bilayer. You can think of vesicles as cellular envelopes that are used to transport materials from one place to another. Vesicles also function in metabolism and enzyme storage as well.

Converts carbohydrates and lipids into cellular energy. Mitochondria Converts carbohydrates and lipids into cellular energy. “Kidney bean” shape with many inner folds.

Organelles Only Found In Plants

Cell Wall Very outside of plant cells Made of cellulose. Protects & provides structure. (Bacteria have a cell wall made of a chitin, not CELLULOSE)

Chloroplasts Performs Photosynthesis Converts sunlight into glucose. Then glucose into cell energy. Green color.

Vacuoles Rarely found in animal cells. Often called vesicles. Often single & large Store water and starch.

Typical Plant Cell Has cell wall, chloroplasts, vacuoles Rarely has lysosomes Square shape

Lysosomes (animals and sometimes plants) Filled with digestive enzymes Breakdown molecules for cell food Breakdown old organelles

Lysosomes digest food particles brought in during phagocytosis (endocytosis) as well as break down dead organelles and waste.

Centrioles (found in some lower plant species) Centrioles spin out the spindle fibers that aid in the division of chromosomes during mitosis

Typical Animal Cell No cell wall, chloroplasts, (few) vacuoles Has lysosomes Has centrioles Many different shapes

Eukaryotes: Larger cells Contain a nucleus Contain membrane bound organelles Protists, fungi, plants and animals classified as Eukaryotes

Differences in prokaryotic and eukaryotic cells Prokaryotes: Lack a nucleus Bacteria are classified as prokaryotes Older than eukaryotes (earliest fossils prokaryotic) Smaller cell than eukaryotes

Wrap-up What organelle do prokaryotes lack that a eukaryotes contain?