The Types of Cells

Two Basic Types of Cells All living things fall into one of two categories of cells: Prokaryotes (bacteria, simple cells) (E. coli, Salmonella, Streptococcus, etc.) Eukaryotes

Prokaryotes Meningitis Pneumonia Staph aureus Gonorrhoeae Found everywhere (most numerous organisms on Earth) Earliest forms of life Unicellular NO membrane-bound organelles 99% are helpful… https://www.youtube.com/watch?v=eksagPy5tmQ Food production Digestion Water purification Decomposers Oil spills Meningitis Pneumonia Staph aureus Gonorrhoeae

D. Shapes of Bacteria Shapes Prefixes 1. 1. = pair = sphere 2. 2. = rod = chain 3. 3. = spiral = bunch Images from: http://biology.clc.uc.edu/courses/bio106/bacteria.htm

Coccus (Spherical) Streptococcus Strep Throat

Escherichia coli (E. coli) Bacillus (Rod) Escherichia coli (E. coli)

Death from anthrax is due to oxygen depletion Bacillus anthracis Death from anthrax is due to oxygen depletion

Spirillum (Spiral) Cholera Intestinal infection caused by ingestion of contaminated food or water.

Prokaryotic Cell Structure

Prokaryotic Cell Structure Nucleoid – the “nuclear” region of a prokaryotic cell where the DNA attaches to the plasma membrane

Prokaryotic Cell Structure Plasmid – Circular DNA containing a few genes to help bacteria survive under some conditions.

Prokaryotic Cell Structure Flagella – long, whiplike protein extensions that rotate like propellers, allowing cells to move (“swim”) through water or other fluids

Eukaryotic Cells More complex than prokaryotes Have many parts (organelles) that each have their own function Advantageous, as each organelle can specialize and become more efficient Compartmentalization

Eukaryotic Organelles Nucleus: genetic control center Contains chromosomes Chromatin: Chromosomes attached to protein Surrounded by a nuclear membrane Main difference b/w prokaryotes & eukaryotes Nucleolus: Area within the nucleus where RNA is synthesized Appears most dense/darkest Produces ribosomes

Nuclear Envelope Nucleus Nucleolus Animal cell Plant Cell Chromatin

Eukaryotic Organelles Nuclear Envelope: Double membrane with thousands of nuclear pores Surrounds the nucleus Controls flow into and out of the nucleus

Eukaryotic Organelles Endoplasmic Reticulum (ER): A system of membranous tubes & channels Located just outside the nucleus Two parts: Smooth: No ribosomes Functions: Synthesis & transport of lipids Detoxifies substances Rough: Coated in ribosomes Function: Protein synthesis & transport

Smooth ER Rough ER Rough ER Smooth ER Animal cell Plant Cell

Eukaryotic Organelles Ribosomes: Small bodies of RNA floating in the nucleus or attached to rough ER Site of protein synthesis Tiny, round objects Found in both prokaryotic and eukaryotic cells

Animal cell Plant Cell Ribosomes

Eukaryotic Organelles Golgi Apparatus: Stack of flattened membranous sacs/tubes Located near the ER Can break off sections to move around cell Functions: Sorts and modifies proteins Packages materials in vesicles for use within the cell or export out of the cell

Animal Cell Plant Cell Golgi Apparatus

Eukaryotic Organelles Mitochondrion: “power plant” of cell Double-membraned organelle Membranes separated by matrix Cristae: folds of inner membrane Major site of ATP synthesis

Animal cell Plant Cell

Eukaryotic Organelles Chloroplast: Double-membrane organelle in plant cells Site of photosynthesis Captures solar energy, converts it to chemical energy Large stacks of membranes containing green pigment chlorophyll NOT IN ANIMAL CELLS

Chloroplasts Animal cell Plant Cell

Eukaryotic Organelles Vacuole: Vesicles in a cell that store water & food (among some other substances) Plants: Central Vacuole. Takes up most of volume Give cells their rigidity, store waste products Present in animals, but much smaller

Plant Cell Animal cell Vacuole

Eukaryotic Organelles Lysosome: Vesicle in animal cells (rarely plants) that contains enzymes to digest food, nutrients, organelles, etc. Causes cell suicide (apoptosis) Animal Cell Lysosome

Eukaryotic Organelles Centriole: Tubular structures involved in cell division/reproduction Animals only, NOT in plants Near nucleus Cytoskeleton: Network of protein fibers that help shape the cell Can hold organelles in place or move them around Found in animal and plant cells

cytoskeleton centrioles Animal cell

Eukaryotic Organelles Cytoplasm (Cytosol): Gel-like substance that fills the cell in which the organelles are bathed Found in ALL cells Plasma (Cell) Membrane: Surrounds all cells Phospholipid Bilayer Responsible for letting substances into & out of the cell Not a source of protection!!!

Plant Cell Animal cell Cell Membrane

Eukaryotic Organelles Cell Wall: A rigid structure that surrounds plant & fungal cells NOT found in animal cells Found in prokaryotic cells (similarity) Surrounds plasma membrane Protects the cell and helps maintain its shape Composed of cellulose

Cell wall: Along the perimeter. Plant Cell Animal cell

Eukaryotic Organelles Cilia: Tiny hair-like structures surrounding the cell membrane Used for movement of the cell or moving material along a cell/tissue Flagella: Found in eukaryotic sperm cells Found in bacteria NOT in plants

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