cellular basis of life

brief history of cells

robert hooke

• coined the term “cell”

• discovered cells from a cork

• box-shaped structure (cell)

• it is called a cell because it reminded him of a cell

antoine van leeuwenhoek

• father of microbiology pioneering work in the field of microscopy

• saw bacterias and protozoans

  • now called microorganisms

other contributors to the cell theory

matthias schleiden

• concluded that all plants are made of cells (1838)

theodore schwan

• concluded that all animals are made of cells (1839)

rudolf virchow

• concluded that all cells came from pre-existing cells (1839)

cell theory

• all living things are made up of cells

• it is the basic unit of structure in an organism

• new cells arise from existing cells

• can be multicellular or unicellular

• cells are different

  • prokaryotes

    • pro - “before”

    • karyon - kernel/nucleus

    • “before nucleus”

    • oldest living organisms

    • most numerous

    • has smaller and simpler structures

    • has a nucleoid (not bounded by a membrane)

    • does not have membranous organelles

    • does not contain histones (family of basic proteins)

  • eukaryotes

    • “true nucleus”

    • eu - “true”

    • karyon - kernel/nucleus

    • with nucleus bounded by a membrane

    • contains other membrane-bound organelles

    • more complex

    • mostly multicellular; few unicellular

  • similarities

    • DNA

    • ribosomes (small organelles)

    • cytoplasm (jell-like fluid)

    • cell membrane (controls the ins and out of the cells— maintains homeostasis

archaea (prokaryote)

• extreme environments

  • hydrothermal vests

  • terrestrial hot springs

eubacteria (prokaryote)

• contains dna

• glam positive bacteria - retrain the crystal violet color and stain purple

• glam negative bacteria - lose crystal violet and stain red

fungi (eukaryote)

• multi or uni

• mushrooms, yeast, rice

plantae (eukaryotes)

• comprises all living plants

protista (eukaryotes)

• unicellular in nature

• colony of cells

• greek word “protistos” - very first

animalia

• heterotrophs (cannot make its own food)

parts of a cell

cell membrane a.k.a plasma membrane

• not to be confused with cell wall

  • made of phospholipids, proteins, cholesterols

    • double membrane

    • flexible structure

cytoplasm

• provides shape to the cell

  • fills up the cells thus enabling the organelles to remain in their position

centrosomes and centrioles

• centrosomes

  • microtubule organizing center

  • the centrosomes deplicate before cell division, so they then help to organize the microtubules and the cell division process

  • found near the nucleus

endoplasmic reticulum (ER)

• carry stuff around

• system of folded tube-like structures

• folds proteins

• transports proteins

• site of ribosomes

there are two kinds: smooth ER and rough ER

• rough ER

  • flattened sheets

  • ribosomes attached

  • protein synthesis

  • reads the RNA (mRNA) sequence and translates that genetic code into a specified string of amino acids, which grow into long chains that fold to form proteins

  • protein

  • smooth ER

    • tubular

    • factory-warehouse

    • enzymes creates the lipids

    • synthesis of lipids, steroids, and carbohydrates

    • cell detox and stores ions

• golgi apparatus

  • protein processing and packaging

    • sends product out to different parts of the cell

• vesicles

  • phospholipid membranes

    • ship golgi body products

• lysosome

  • cell digestion

    • enzyme sacks

    • cell waste > building material

• nucleus

  • the brain of the cell

    • stores "DNA"

    • makes cell LAWS

    • uses DNA to make LAWS

• chromatin

  • seen inside the nucleus

    • chains of molecules thaat hold the DNA of the cell

    • cell division > chromosomes

• mitochondria

  • powerhouse of the cell

    • respiration

    • energy > ATP (adenosine triphosphate)

• flagellum and cilia

  • only found in animal cell

    • cell appendages; composed of microtubes wrapped in an extension of plasma membrane; for locomotion

    • cilia

      • hair like structure

    • flagellum

      • whip-like structure

  • types of flagellar arrangement

    • polar / monotrichous

      • single flagellum at one pole

      • lophotrichous

        • tuft of flagella at one pole

      • amphitrichous

        • flagella at both poles

      • peritrichous

        • flagella all over

      • amphilophotrichous

        • tuft of flagella at both ends

• PLANT CELL

  • cell wall

    • surrounds the plasma membrane

      • made of cellulose and lignin (very tough)

  • plastids

    • make and store needed compounds

      • hold chloroplasts

  • central vacuole

    • storage of water and materials

      • give plants its distinctive shape

      • reinforces the plant

      • supports cell structure

  • plant cells

    • have choloroplasts

      • have vacuoles

      • can absorb liquids

      • creates food by photosynthesis

      • has cell wall made of cellulose

  • animal cells

    • have no cell walls

      • eats other cells

      • cannot absorb much liquid because it has no cellulose

      • can move through appendages

      • can form a variety of shapes

      • have lysosomes

  • plant cells and animal cells

    • have a nucleus

      • eukaryotic

      • same size