Cells Bio 1 Mr. Hellmer

What is a cell? Basic functional, structural, and biological unit of all known living organisms. Surrounded by a membrane (lipid bilayer) Cells can replicate independently (cells only come from other cells) Building blocks of life

Cell Theory All living things are made of one or more cells Basic unit of structure and function in organisms Cells come only from the reproduction of existing cells

Size, shape, and internal organization varies Diversity Size, shape, and internal organization varies Humans have at least 200 different cell types Volume grows faster than surface area Surface allows for passage of materials Shape enables function Nerve Cell Red and White Blood Cells

All cells are surrounded by a Cell Membrane Not all cells are the same inside: Eukaryotes - have membrane bound nucleus Prokaryotes- no membrane bound nucleus or membrane bound organelles Eukaryotic Cell Prokaryotic Cell

Prokaryotes Simple organization No membrane bound organelles No membrane bound nucleus Can have a cell wall Usually circular DNA Unicellular Examples: Bacteria (Escherichia coli & Staphylococcus aureus) Archaea (Halobacteria) Halobacteria (Archaea) E. Coli (Bacteria)

Plants, animals, fungi, protists Eukaryotes Complex organization Membrane bound organelles Membrane bound nucleus Linear DNA Multicellular and unicellular Examples: Plants, animals, fungi, protists

Prokaryotes and Eukaryotes Simple organization No membrane bound organelles No membrane bound nucleus Can have a cell wall Usually circular DNA Unicellular Eukaryotes Complex organization Membrane bound organelles Membrane bound nucleus Linear DNA Multicellular and unicellular

Prokaryote

Eukaryote

Eukaryote vs. Prokaryote

Cell Parts Prokaryotes and Eukaryotes Eukaryotes Cell (plasma) membrane Cell wall (bacteria and plants) Cytoplasm Ribosomes Flagella DNA RNA Eukaryotes Nucleus Nuclear envelope Nucleolus Mitochondria Endoplasmic Reticulum Golgi apparatus Lysosome Vacuole Cytoskeleton Centriole Cilla and Flagella Chloroplast Cell Wall Central Vacuole plasma membrane, nuclear envelope, nucleus, nucleolus, cytoplasm, mitochondrion, endoplasmic reticulum, Golgi apparatus, lysosome, ribosome, vacuole, cell wall, chloroplast, cytoskeleton, centriole, cilium, flagellum

Cell (plasma) Membrane Allows substances to pass into and out of the cell Known as selectively permeable Made primarily of lipids and proteins Phospholipid bilayer Proteins are attaching site for signals and also allow passage of molecules

Organelles Internal functional structures of a cell Prokaryotes only have ribosomes All others are in Eukaryotes

Nucleus Stores DNA (hereditary information) Surrounded by nuclear membrane and nuclear envelope Where RNA is copied from DNA RNA passes through nuclear pores (small holes in nuclear envelope) Contains chromatin (DNA and protein) which coil up when the cell will divide into chromosomes

Nucleolus Located in the nucleus Where ribosomes are made

Cytoplasm Between cell membrane and nucleus Contains: cytosol (gelatin-like fluid) organelles, salts, minerals, and organic molecules

Mitochondria Where ATP (energy) is made from glucose (cell respiration) Drives chemical reactions in a cell Powerhouse of cell More energy use, more mitochondria 2 membranes Outer membrane is barrier Inner membrane has folds (cristae) that increase surface area where reactions occur Have their own DNA Grow and divide only from other mitochondria

Endoplasmic Reticulum Synthesis and transport of molecules inside cell (cellular highway) Two types of ER: Rough ER has ribosomes on it More in cells that make a lot of proteins Smooth ER doesn’t have ribosomes Makes steroids (gland cells) calcium (muscle cells) breakdown toxins (liver cells) Both types may be continuous with each other

Golgi Apparatus Processing, packaging, and secreting of molecules “UPS” of cell Works with ER

Lysosome Small spherical vesicle containing enzymes Digests proteins, carbohydrates, lipids, DNA, and RNA, old organelles, viruses, bacteria Garbage disposal of cell Rare in plants #12

Ribosome Composed of protein and RNA (no membrane) Packaged from the nucleolus Synthesis of proteins Free ribosomes in the cytoplasm – proteins for the cell Ribosomes on Rough ER – proteins for export

Cytoskeleton Long protein strands that maintain the shape of the cell Microfilaments Smallest strands Movement of cell and contraction of muscle cells Microtubules (hollow tubes) Largest strands Organized by centrosome Form spindle fibers for cell division

Cillia and Flagella Part of the cytoskeleton Cilia is short and numerous On many unicellular (movement) Also on some multicellular Example: respiratory cells Flagella is a long and less numerous Example: 1 flagella on sperm cells

Centriole Make up centrosome Organizes microtubules (mitotic spindle during cell division) Not present in plants

Plant Cells Cell Wall surrounds cell membrane Causes rigidity, Central Vacuoles store enzymes and metabolic wastes May take up to 90% of cell May be toxic which provide defense Plastids contain DNA and store starch or pigments (which absorb light) Chloroplast: which contain thylakoids (sacs) Chlorophyll and Carotenoids Photosynthesis

Cell Transport Passive Transport across a membrane -Does NOT require energy -Moves down the concentration gradient, from high to low -Diffusion, Osmosis, Facilitated Diffusion   Active Transport across a membrane -Moves up the concentration gradient, from low to high -Requires energy -Sodium–Potassium Pump, Endocytosis, Exocytosis Osmosis and how cells react in different conditions - Outside of cell has lower concentration of solute than inside = water diffuses in - Outside of cell has higher concentration of solute than inside = water diffuses out - Outside of cell has equal concentration of solute to inside = water diffuses in and out