We all of us are what happens when

“We, all of us, are what happens when a primordial mixture of hydrogen and helium evolves for so long that it begin to ask where it came from” -Jill Tarter Life’s home: The Cell Chapter 4

Cell Theory �All living organisms are composed of cells � Unicellular �Cells or multicellular come from _______ cells Modern additions to theory � All cells use energy and have a metabolism � All cells have similar chemical composition � All cells have genetic information in the form of DNA

Cells are Specialized �Over ____ different cells in the human body �You are made of trillions of cells!! Reproductive cells Red blood cell Cardiac muscle cells Bone cells Nerve cell

Why so small? Surface area to volume ratio! �Greater surface area means greater ____ � Transporting the cell stuff into and out of

Two Main Groups of Cells Prokaryotic Eukaryotic (Bacteria and Archaea) (Protists, Plants, Animals and Fungi) *Not to scale

Prokaryotic and Eukaryotic Cells Eukaryotic cell Prokaryotic cell

Size of Prokaryotic Cells

Domains of Life �Bacteria � Unicellular prokaryotes �Archaea � Unicellular prokaryotes � Extremophiles �Eukarya � Unicellular and _____ eukaryotes �Protists �Fungi �Plants �Animals

Domain: Bacteria �Prokaryotic cells �No membrane bound nucleus or organelles �Single-celled �Asexual organisms reproduction �______ in cell wall separates bacteria from archaea

Domain: Archaea Prokaryotic cell but similar to Eukaryotes in DNA replication and Protein synthesis �More closely related to ______________: organisms that live grow best in one or more conditions that would kill most organisms �Thermophiles: live in extremely hot environments �Halophiles: live in extremely salty environments �Methanogens: Methane releasing archaea that are poisoned by oxygen

A Borrowed Life Virus: an infections particle incapable of replicating outside of a cell, which consists of an RNA or DNA genome enclosed in a protein coat (capsid) � ________ parasites Arguments for describing viruses as non-living � Can not _____ outside of host cell � Can not carry out ________ outside of host cell � Lack ribosomes and enzymes HIV attacking a white blood cell

Prokaryotic Cells Pili: attachment structures on the surface of some prokaryotes Bacterial chromosome A typical rod-shaped bacterium ____: location of cell’s DNA (not enclosed in a membrane) Ribosomes: site of protein synthesis Cell wall: rigid structure outside of cell membrane ______: sticky outer coating on many prokaryotes Flagella: locomotion organelles in some bacteria A thin section through the bacterium Bacillus coagulans

Eukaryotic Cells

Prokaryotic Reproduction ______: DNA replicates and then the cell divides into two separate cells

Prokaryotic and Eukaryotic Cells Characteristics Prokaryotic Cells Eukaryotic Cells Cell Size Small (0. 2 – 2. 0 µm in diameter) Large (10 – 100 µm in diameter) Organization Always single celled Often _________ Nucleus _________ or nucleus, Nucleoid Membrane bound nucleus Membrane-enclosed organelles ______ Present (e. g. lysosomes, Golgi complex, mitochondria) Cytoplasm No cytoskeleton or cytoplasmic streaming Cytoskeleton, cytoplasmic streaming Ribosomes Present, smaller size Present, larger size Chromosomes (DNA) Usually _______________ chromosomes Cell division Binary fission Involves mitosis Sexual Recombination None, transfer of DNA only Involves meiosis

Major Components of Eukaryotic Cells � Nucleus: membrane bound region that contains the cell’s DNA � Organelles: highly organized structure in the cell that performs a specific cellular function � Cytosol: protein rich, jelly-like fluid in which the organelles are immersed � Cytoskeleton: internal supports of the cell made up of protein fibers � Plasma membrane: a complex, ______ membrane that encloses the cytoplasm and regulate passage of ions and molecules into and out of the cell Nucleus Other organelles Cytosol Cytoskeleton Plasma membrane

Origin of Organelles Autogenesis: _______ of prokaryote plasma membranes lead to compartmentalization Endosymbiosis Autogenesis � Endoplasmic reticulum, golgi, nuclear membrane _________: one organism lives inside the cell of another organism � Mitochondria, chloroplasts Endosymbiosis

Specific Functions of Organelles

The Nucleus �Control �Stores center of the cell Chromosome DNA � Chromatin: uncoiled DNA � _______: coiled DNA containing genes �Nuclear membrane � Contains Nucleolus pores �Nucleolus: Nucleu s region inside nucleus where ribosomal subunits in manufactured Gen e

Endomembrane System Rough endoplasmic reticulum: network of membranes that aid in protein processing � Studded with ______ Smooth endoplasmic reticulum: network of membranes that functions in the synthesis lipids and ______ of harmful molecules including alcohol, drugs and metabolic wastes. � Lacks ribosomes

Golgi Complex �Protein processing and distribution �_______ determine shipping route

Lysosomes �_______ old cellular products and foreign material � Cell “digestive system” �Recycles � Go useable molecules on to form new organelles �Found in _______ cells

Protein Production Summary

Protein Production: Step 1 _______: process in which a section of DNA is copied onto messenger RNA (m. RNA) RNA polymerase m. RNA Direction of transcription

Protein Production: Step 2 Translation: process by which a _____ is produced in a ribosome from information encoded within a messenger RNA

Mitochondria �Creates Adenosine Triphosphate (ATP) from food (cellular respiration) � ATP = cellular energy �Requires macromolecules from food and O 2, expels CO 2 �Breakdown generates _____ (metabolic heat)

Cell Cytoskeleton �Aids in cell structure, cell movement and transport of materials within cell Made up of three types of protein fibers � Microfilaments: solid, rod-like fibers that aid in cell division and changes in cell shape � Intermediate filaments: rope-like structures that give the cell strength and maintain cell shape � ______: long hollow tubes that aid in the movement of molecules and organelles throughout the cell

Cell Movement Modified microtubules � ____: short, hair-like projections often found in large numbers on the exterior of the cell. � Used for locomotion or movement of fluid around a cell. � Flagella: long, tail-like extension used for locomotion. � Typically one per cell

Plant and Animal Cells

Plant and Animal Cells Animal Cell Plant Cell Both

Plant Cells: Chloroplasts �Contain chlorophyll (photosynthesis) �Endosymbiosis Thylakoid

Plant Cells: Central Vacuole Central vacuole � Maintains cell pressure � Stores _____ � Degrades cell waste products Large central vacuole

Plant Cells: Cell Wall �_____: polysaccharide that is a main structural component of cell walls �Limits water absorption �Structural strength

Cell Communication Plant Cells �Plasmodesmata: channels between plant cell walls � Creates continuous cytoplasm � Do not open and close

Cell Communication Animal Cells �Gap junctions: protein assemblage that forms a communication channel between adjacent animal cells � Open and close as needed