Introduction to Cells Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Bacterial Cell Animal Cell Plant Cell

Number of Cells Organisms may be: Unicellular – composed of one cell Multicellular- composed of many cells that may organize

Cells May be Prokaryotic or Eukaryotic Prokaryotes: include bacteria & lack a nucleus or membrane-bound structures called organelles Eukaryotes: include most other cells & have a nucleus and membrane-bound organelles (plants, fungi, & animals)

Prokaryote vs Eukaryote Two structural types of cells are recognized: Prokaryotic Archaea and bacteria Eukaryotic: plants, algae, fungi, protists, and animals (variety) Comparing prokaryotic and eukaryotic cells Prokaryote comes from the Greek words for prenucleus. Eukaryote comes from the Greek words for true nucleus.

Prokaryote Eukaryote Contains plasma membrane Contains plasma membrane Simpler internal structure Absence of nucleus One circular chromosome, not in a membrane No membrane enclosed organelles Peptidoglycan cell walls Binary fission for cell division Smaller Contains plasma membrane Contain nucleus Paired chromosomes, in nuclear membrane Membrane enclosed organelles Simple (polysaccharide) cell walls Cell division by mitosis or meiosis Larger

Structure of Prokaryotic vs. Eukaryotic cell

Prokaryotes – The first Cells Cells that lack a nucleus or membrane-bound organelles Includes bacteria Simplest type of cell Single, circular chromosome copyright cmassengale

Prokaryotes Nucleoid region (center) contains the DNA Surrounded by cell membrane & cell wall (peptidoglycan) Contain ribosomes (no membrane) in their cytoplasm to make proteins copyright cmassengale

Eukaryotes Cells that HAVE a nucleus and membrane-bound organelles Includes protists, fungi, plants, and animals More complex type of cells copyright cmassengale

Differences b/w the 2 types of cells Eukaryotic Prokaryotic Larger Contains membrane bound organelles Contains a nucleus Smaller Does not contain membrane bound organelles No nucleus

a large central vacuole plants plasma membrane prokaryotes Words you can use: Animals bacteria chloroplasts Eukaryotes a large central vacuole plants plasma membrane prokaryotes All cells have a: And are grouped into two broad categories: Which are mainly: Some contain yeast and algae Which contains unique structures such as: Cell walls

a large central vacuole plants plasma membrane prokaryotes Words you can use: Animals bacteria chloroplasts Eukaryotes a large central vacuole plants plasma membrane prokaryotes All cells have a: Plasma membrane And are grouped into two broad categories: prokaryotes eukaryotic Which are mainly: bacteria plants animals Some contain yeast and algae Which contains unique structures such as: Cell walls chloroplasts A large central vacuole

Viruses Non cellular Obligate intracellular parasites They must live inside another cell to survive Have only one type of nucleic acid DNA or RNA (never both) Single or Double stranded Protein coat (no plasma membrane) Few to no enzymes Takes enzymes and use host cell metabolic machinery No metabolic activity They require a host cell to exhibit the characteristics of life. Virus diversity Different viruses have different hosts Only some viruses cause disease

Structure & Organelles Vocabulary Plasma Membrane Cytoskeleton Nucleus Nucleolus Golgi Apparatus Endoplasmic Reticulum Chloroplast Mitochondria Lysosome Vacuole Vesicle Cell wall Ribosome Cytosol Cytoplasm

Organelles Very small (Microscopic) “little organs” that carry out specific functions within each cell Perform various functions for a cell Found in the cytoplasm May or may not be membrane-bound

Eukaryotic: Animal Cell

Eukaryotic: Plant Cell

Prokaryotic Cell

Plasma Membrane (AKA cell membrane Function: A flexible boundary that controls the movement of substances in and out of the cell. Key word: Selective permeability. Cell Type: All cells Analogy: __________

Cell Membrane in Plants Lies immediately against the cell wall in plant cells Pushes out against the cell wall to maintain cell shape

Cell Wall Nonliving layer Found in plants, fungi, & bacteria Made of cellulose in plants Made of peptidoglycan in bacteria Made of chitin in Fungi Cell Type: Plants Analogy:_____________________________

Cell Wall Supports and protects cell Found outside of the cell membrane

More on Cytoplasm Contains organelles to carry out specific jobs Collective term for cytosol plus the organelles suspended within the cytosol Found in ALL cells Analogy:______________________

Cytosol The fluid surrounding the cytoplasm’s organelles, internal membranes, and cytoskeleton fibers Analogy:_______________________ copyright cmassengale

Cytoskeleton Helps cell maintain cell shape and supporting structure Also help move organelles around Made of proteins Microfilaments are threadlike & made of ACTIN Microtubules are tubelike & made of TUBULIN Analogy:____________________________

Cellular Support Cytoskeleton is made of microtubules thin, hollow cylinders made of protein, & microfilamentsthin solid protein fibers

Cytoskeleton MICROTUBULES MICROFILAMENTS copyright cmassengale

Nucleus Function: The nucleus contains the cells DNA, stores information used to make proteins For cell growth, function & reproduction. Key Word: Control Center Cell Type: All Eukaryotic Cells Analogy: ____________

Nucleolus Inside nucleus Cell may have 1 to 3 nucleoli Disappears when cell divides Makes ribosomes that make proteins Analogy:____________________ copyright cmassengale

Endoplasmic Reticulum - ER Network of hollow membrane tubules Connects to nuclear envelope & cell membrane Functions in Synthesis of cell products & Transport Analogy?_________________________________ Two kinds of ER ---ROUGH & SMOOTH copyright cmassengale

Rough Endoplasmic Reticulum (Rough ER) Has ribosomes on its surface Makes membrane proteins and proteins for EXPORT out of cell copyright cmassengale

Smooth Endoplasmic Reticulum Smooth ER lacks ribosomes on its surface Is attached to the ends of rough ER Makes cell products that are USED INSIDE the cell copyright cmassengale

Functions of the Smooth ER Makes membrane lipids (steroids) Regulates calcium (muscle cells) Destroys toxic substances (Liver) copyright cmassengale

 Ribosomes “Protein factories” for cell Small particles of RNA and protein found throughout the cytoplasm. Produce proteins by following coded instructions that come from the nucleus. Join amino acids to make proteins Process called protein synthesis Analogy:________  copyright cmassengale

Golgi Apparatus Function: It’s a flattened stack of membranes that modifies, sorts & packages proteins into sacs. Key Word: Packing & Sorting Cell Type: All Eukaryotic Cells Analogy: ____________

Golgi Bodies Modify, sort, & package molecules from ER Look like a stack of pancakes Modify, sort, & package molecules from ER for storage OR transport out of cell copyright cmassengale

Golgi copyright cmassengale

Vesicles -small saclike organelles that store and transport materials around the inside of cells copyright cmassengale

Chloroplasts Function: Capture light energy & convert it into chemical energy through photosynthesis. Key Word: Producer of energy Cell Type: Euk. Plant cell Analogy: ____________

Vacuoles Fluid filled sacks for storage Small or absent in animal cells Plant cells have a large Central Vacuole No vacuoles in bacterial cells Analogy:_______________ copyright cmassengale

Vacuoles In plants, they store Cell Sap Includes storage of sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes copyright cmassengale

Mitochondria Function: It converts fuel particles (mainly sugar) into usable energy. Key Word: Powerhouse Cell Type: All Eukaryotic Cells Analogy: ____________

MITOCHONDRIA CONT Has its own DNA Surrounded by a DOUBLE membrane Folded inner membrane called CRISTAE (increases surface area for more chemical Reactions) Interior called MATRIX copyright cmassengale

Interesting Fact --- Mitochondria Come from cytoplasm in the EGG cell during fertilization Therefore … You inherit your mitochondria from your mother! copyright cmassengale

Lysosomes Function: Processes enzymes that digest excess or worn out organelles, wastes. Key Word: Gets rid of waste Cell Type: Euk. Animal Cells Analogy: ____________

Similarities between plant cells and animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria

Differences between plant cells and animal cells Relatively smaller in size Relatively larger in size Irregular shape Regular shape No cell wall Cell wall present

Differences between Plant Cells and Animal Cells Vacuole small or absent Large central vacuole Glycogen as food storage Starch as food storage Nucleus at the center Nucleus near cell wall

Cell Movement with Cilia & Flagella copyright cmassengale

Cilia & Flagella Cilia short, numerous, hair-like projections that move in a wavelike motion

Flagella larger projections that move w/ a whip-like motion

Cilia & Flagella Cilia are shorter and more numerous on cells Flagella are longer and fewer (usually 1-3) on cells copyright cmassengale

Cilia Moving Away Dust Particles from the Lungs Respiratory System copyright cmassengale

Cell Size Question: Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse? copyright cmassengale

Cell Size Question: Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse? About the same size, but … The elephant has MANY MORE cells than a mouse! copyright cmassengale