CELLS The Cell Theory All living things are

CELLS

The Cell Theory • All living things are made of cells. • Cells are the basic structural unit of life. • All cells come from pre-existing cells.

Prokaryotes and Eukaryotes

Prokaryotes and Prokaryotic Cells • NO membrane bound organelles – Most functions within the cell happen in one common space – No compartmentalization or specialization; single cells function alone (no tissue formation) • Generally smaller and more simple • Examples – Archaea – Bacteria

Prokaryotes (Archaea and Bacteria) • Cell wall – Made of peptidoglycan (sugars and amino acids) • Capsule – Protective shell • Nucleoid region – Clump of DNA • Plasmid – Extra loops of DNA • Ribosomes – Structures that translate DNA and produce proteins • Pili – Hairs for attachment

Eukaryotes And Eukaryotic Cells • Membrane bound organelles – Allow for compartmentalization, specialization, tissue formation (multiple cells working together in a single unit) • Generally larger and more complex • Examples – Animals – Plants – Fungi – Protists

Animal Cells • NO cell wall • Centrioles – Made of microtubules help in cell division

Plant Cells • Cell wall of cellulose • Centrosomes – made of microtubules help in cell division • Chloroplasts – convert energy from sun into sugar (photosynthesis) through cellular respiration • Central vacuole – Stores water for structural support

Fungus Cells • Cell wall of chitin (same thing insect exoskeletons are made of) • Spindle pole bodies made of microtubules help in cell division • NO chloroplasts or photosynthesis

Protists • First eukaryotes – Early ancestors of animals, plants and fungi • Usually single-celled – All have a single-celled stage in life cycle – Sometimes colonial (group together) • Animal-like, plant-like, fungal-like – May be a combination of characteristics

Prokaryotic Cell Movement • Flagella – Mechanical complex of proteins organized into rotary motor – Rotates like a propeller • Gliding Motion – Utilizes secretions and viscosity

Eukaryotic Cell Movement • Flagella – Tail like structure that uses whipping motion for locomotion; – Ex: spermatozoa, protists • Cilia – Hair like structure that uses beating motion for locomotion or movement of substances – Ex: Bronchial and fallopian tube lining, protists • Pseudopods – Amoebic, blob-like movement – Ex: White blood cells, protists

Cell Structures • Cytoplasm: cellular matrix; the jelly-like substance everything is suspended in; made mostly of water • Organelles: “little organs; ” structures found within the cell that carry out certain functions – Only eukaryotes have membrane bound organelles

Cell Boundaries • Plasma Membrane: all cells have outer membrane containing the cytoplasm and organelles • Cell Wall: thick, hard, outer layer for structure and protection; most prokaryotes and some eukaryotes. Not in animal cells.

Next… • Cell membranes and cellular transport