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Cell Structure and Organelle Function. What Is the Cell Theory?. Why are cells small?. Cheek cells. microscopyu.com. All Cells Share Common Features. Members of Bacteria, Eukaryota, and Archaea share common cellular features. Plasma Membrane.

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Cell structure and organelle function
Cell Structure and Organelle Function



Why are cells small
Why are cells small?

Cheek cells. microscopyu.com


All cells share common features
All Cells Share Common Features

  • Members of Bacteria, Eukaryota, and Archaea share common cellular features.


Plasma membrane
Plasma Membrane

  • A plasma membrane encloses all cells and regulates material flow


Cytoplasm
Cytoplasm

  • Cytoplasm

    • Interior fluid

    • Where cell’s metabolic reactions occur

    • Contains organelles

    • Fluid portion (cytosol) contains water, salts, and organic molecules


Genetic material
Genetic Material

  • All cells use DNA(deoxyribonucleic acid) as a hereditary blueprint

  • All cells use RNA(ribonucleic acid) to copy DNA to make proteins


All cells share common features1
All Cells Share Common Features

  • All cells obtain energy and nutrients from the environment

  • All cells use common building blocks to build the molecules of life


There are two basic cell types
There Are Two Basic Cell Types

  • Cells are either:

    • Prokaryotic

      • Before nucleus

    • Eukaryotic

      • True nucleus

      • Membrane

        bound organelles

www.ucmp.berkeley.edu/alllife/eukaryota.html


Eukaryotic cells
Eukaryotic Cells

  • Eukaryotic cells > 10 µm long

  • Have membrane-enclosed organellesthat perform specific functions




The cytoskeleton1
The Cytoskeleton

  • Main functions of cytoskeleton

    • Maintaining and changing cell shape

    • Providing for cell movement

    • Providing for organelle movement, including vesicle endo- and exocytosis

    • Facilitating cell division in chromosome movements and cytokinesis


Cilia and flagella
Cilia and Flagella

  • Cilia and flagella are extensions of the plasma membrane

  • Cilia

    • Short, hair-like structures, numerous

  • Flagella

    • Longer, whip-like, fewer in number

  • Functions

    • motility

    • Cilia - create currents of moving fluid in environment


The nucleus
The Nucleus

  • Control center of cell

  • Contains genetic information (in eukaryotes)

  • Contains:

    • Nuclear envelope

    • Chromosomes

    • Nucleolus


System of membranes
System of Membranes

  • Membrane system includes the plasma membrane and organelle membranes


Vesicles
Vesicles

  • Vesicles

    • membranous sacs that carry substances throughout the cell


Endoplasmic reticulum
Endoplasmic Reticulum

  • A series of enclosed, interconnected channels within cell

  • Two forms of ER

    • Smooth ER

    • Rough ER


Golgi apparatus
Golgi Apparatus

  • a set of stacked flattened sacs


Fate of substances made in the membrane system 3
Fate of Substances Made in the Membrane System (3)

  • Secreted proteins made in RER, travel through Golgi, then are exported through plasma membrane


Fate of substances made in the membrane system 31
Fate of Substances Made in the Membrane System (3)

  • Digestive proteins made in RER, travel through Golgi, and are packaged as lysosomes for use in cell

    • Lysosomes fuse with food vacuolesand digest food into basic nutrients


Fate of substances made in the membrane system 32
Fate of Substances Made in the Membrane System (3)

  • Membrane proteins and lipids made in ER, travel through Golgi, and replenish or enlarge organelle and plasma membranes


Vacuoles serve many functions
Vacuoles Serve Many Functions

  • Fluid-filled sacs with a single membrane

  • Contractile vacuolesin freshwater organisms used to collect and pump water out


Vacuoles serve many functions1
Vacuoles Serve Many Functions

  • Plant central vacuolesused in several ways

    • Maintain water balance

    • Store hazardous wastes, nutrients, or pigments

    • Provide turgor pressure on cytoplasm to keep cells rigid


Mitochondria extract food energy
Mitochondria Extract Food Energy

  • Mitochondria- round, oval, or tubular sacs of double-membranes

    • Inner membrane is folded into cristae

    • Intermembrane compartment lies between inner and outer membranes

    • Matrixspace within inner membrane


Mitochondria extract food energy1
Mitochondria Extract Food Energy

  • Mitochondria may be remnants of free-living prokaryotes (endosymbiotic hypothesis)

thebrain.mcgill.ca


Plants use plastids for storage
Plants Use Plastids for Storage

  • Plastids found only in plants and photosynthetic protists

    • Ex. chloroplasts

  • Surrounded by a double membrane

  • Functions

    • Storage for photosynthetic products

    • Storage of pigment molecules


Chloroplasts
Chloroplasts

  • Chloroplasts- specialized organelles surrounded by a double membrane

    • Outer membrane

    • Inner membrane encloses the stroma space

      • Stacked hollow membranous sacs (grana) within stroma are called thylakoids


Chloroplasts1
Chloroplasts

  • Contain chlorophyll and other pigments that capture sunlight, CO2, and water and are used to make sugar (photosynthesis)


Prokaryotic cells
Prokaryotic Cells

  • Most prokaryotic cells (bacteria) are < 5 µm long


Prokaryotic cell wall
Prokaryotic Cell Wall

  • A stiff cell wall is usually present


Prokaryotic cells1
Prokaryotic Cells

  • Motility by flagella

  • May have capsules or slime layerson their surfaces

  • Pili and fimbriae are protein projections in some bacteria that further enhance adhesion

E. Coli with fimbriae. mgm.stonybrook.edu

E. Coli with fimbriae. med.upenn.edu


Prokaryotic cells2
Prokaryotic Cells

  • Cell shapes: bacilli, cocci, or spirilla

abe.ufl.edu


Prokaryotic cells3
Prokaryotic Cells

  • Single, circular chromosome of DNA in area called the nucleoid

  • Small rings of DNA (plasmids) located in the cytoplasm


Prokaryotic cells4
Prokaryotic Cells

  • No nuclear membrane or membrane-bound organelles present

  • Some have internal membranes used to capture light

  • Cytoplasm may contain food granules



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