Biology - Cells

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  • Biology is the study of life. It is the study of living things and their interactions with their environment.
  • 1665
    • English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork.
    • He described the cells as tiny boxes of a honeycomb.
    • He thought that cells only existed in plants and fungi.
  • Anton van Leuwenhoek
    • 1673 - used a handmade microscope to observe pond scum and discovered single - celled organisms which he called "animalcules".
    • He also observed blood cells from fish, birds, frogs, dogs, and humans.
    • Therefore, it was known that cells are found in animals as well as plants.
  • 150 - 200 Year Gap
    • Between Hooke/Leuwenhoek discoveries and the mid 19th century (1850's), very little cell advancements were made.
    • This is probably due to the widely accepted, traditional belief in spontaneous generation - making living things from non-living things.
  • 19th Century Advancement
    • However, there was much doubt around the idea of Spontaneous Generation. To many it didn't make sense.
    • Conclusively disproved by Louis Pasteur.
  • Development of the Cell Theory
    • 1838 - German Botanist, Matthias Schleiden, concluded that all plant parts are made of cells.
    • 1839 - German Physiologist, Theodor Schwann, stated that all animal tissues are composed of cells.
    • 1858 - Rudolf Virchow, after extensive study of cellular pathology, concluded that cells must arise from pre-existing cells.
  • Development of the Cell Theory
    • 1838 - German Botanist, Matthias Schleiden, concluded that all plant parts are made of cells.
    • 1839 - German Physiologist, Theodor Schwann, stated that all animal tissues are composed of cells.
    • 1858 - Rudolf Virchow, after extensive study of cellular pathology, concluded that cells must arise from pre-existing cells.
  • The Initial Cell Theory
    • All organisms are composed of one or more cells.
    • The cell is the basic unit of life in all living things.
    • All cells are produced by the division of pre-existing cells.
  • The Initial Cell Theory
    • All organisms are composed of one or more cells.
    • The cell is the basic unit of life in all living things.
    • All cells are produced by the division of pre-existing cells.
  • The Initial Cell Theory
    • All organisms are composed of one or more cells.
    • The cell is the basic unit of life in all living things.
    • All cells are produced by the division of pre-existing cells.
  • Modern Day Cell Theory
    The basic idea of the cell theory withstood the test of time however, there were a few additions as our knowledge over the years increased.
  • The Current Cell Theory
    • All organisms are composed of one or more cells.
    • The cell is the basic unit of life in all living things.
    • All cells are produced by the division of pre-existing cells.
    • Energy flows inside cells.
    • Cells contain DNA which determines the organisms characteristics and is passed down from one generation to another.
  • The Current Cell Theory
    • All organisms are composed of one or more cells.
    • The cell is the basic unit of life in all living things.
    • All cells are produced by the division of pre-existing cells.
    • Energy flows inside cells.
    • Cells contain DNA which determines the organisms characteristics and is passed down from one generation to another.
  • The Current Cell Theory
    • All organisms are composed of one or more cells.
    • The cell is the basic unit of life in all living things.
    • All cells are produced by the division of pre-existing cells.
    • Energy flows inside cells.
    • Cells contain DNA which determines the organisms characteristics and is passed down from one generation to another.
  • The Current Cell Theory
    • All organisms are composed of one or more cells.
    • The cell is the basic unit of life in all living things.
    • All cells are produced by the division of pre-existing cells.
    • Energy flows inside cells.
    • Cells contain DNA which determines the organisms characteristics and is passed down from one generation to another.
  • The Current Cell Theory
    • All organisms are composed of one or more cells.
    • The cell is the basic unit of life in all living things.
    • All cells are produced by the division of pre-existing cells.
    • Energy flows inside cells.
    • Cells contain DNA which determines the organisms characteristics and is passed down from one generation to another.
  • The Two Main Types of Cells
    • Prokaryotes
    • Eukaryotes
  • Prokaryotic and Eukaryotic Cells
    1. Both cells contain DNA.
    2. Eukaryotic cells contain a nucleus.
    3. Both cells contain a cell membrane.
    4. Prokaryotic cells existed 3 billion years ago.
    5. Eukaryotic cells existed 2 billion years ago.
    6. Prokaryotic cells are about 0.5 nano metres in size.
    7. Eukaryotic cells include plant, animal, fungi, protist cells.
    8. Prokaryotic cells include bacteria and archea cells.
    9. Both cells contain cytoplasm.
    10. Both cells contain Ribosomes.
  • DNA
    Eukaryotes: DNA is stored and protected inside the nucleus
    Prokaryotes: DNA is located in the cytoplasm as a circular plasmid
  • DNA is tightly coiled within each chromosome.
  • DNA molecules in a human chromosome would be between 1.7 and 8.5 centimetres long, depending on the chromosome.
  • Function of Cells
    Cells work together to perform the basic processes of life:
    1. Ridding the body of wastes
    2. Releasing energy from food
    3. Making new cells for growth and repair
  • Function of Cells
    Cells work together to perform the basic processes of life:
    1. Ridding the body of wastes
    2. Releasing energy from food
    3. Making new cells for growth and repair
  • Function of Cells
    Cells work together to perform the basic processes of life:
    1. Ridding the body of wastes
    2. Releasing energy from food
    3. Making new cells for growth and repair
  • Chromosomes
    • Coiled strand of DNA
  • Gene

    Section of DNA strand
  • DNA = Deoxyribonucleic Acid
  • Nucleotide
    Building blocks of DNA.
    Three smaller parts
    • Deoxyribose sugar molecule
    • Phosphate group
    • Nitrogenous Base
  • Nitrogenous Bases (DNA)
    Purines
    • Adenine
    • Guanine
    Pyrimidines
    • Thymine
    • Cytosine
  • Hydrogen Bonds
    A type of weak chemical bond between two groups of atoms; the bond between the nitrogen bases in the double helix.
  • DNA -> RNA -> Protein
    DNA is used for making mRNA.
    RNA is used for making proteins.
  • DNA Transcription
    The process of creating a complementary RNA copy of a sequence of DNA
    • RNA polymerase binds to a specific sequence within the gene
    • The two strands come apart.
    • One of the strands serve as a template strand and is used to generate mRNA
    • The RNA polymerase goes along the template strand and reads the DNA sequence as it synthesises mRNA.
    • mRNA then leaves nucleus through nuclear pores and moves into cytoplasm.
    • It then finds ribosomes in ER where translation occurs.
  • Cell Wall
    • Provides protection and rigid outer layer to the cell
    • Contain cellulose
    • Found in prokaryotic cells, fungi cells, algae cells, and plant cells.
  • Chloroplast
    • Responsible for photosynthesis
    • Contains chlorophyll which absorbs all light from the sun except green light.
    • Only in plant cells
    • Produce glucose
  • Vacuole
    • Helps as storage and disposal of various substances such as water, nutrients, and waste products.
    • Isolates materials that may be harmful or threatening to the cell
    • Help hold waste products
    • Export unwanted substances from the cell
    • Contain water
    • Maintain internal hydrostatic pressure
    • maintain an acidic internal pH
    • Temporary "trash can" for the cell
    • Like the cells "Warehouse"
    • Has no basic shape or size, structure varies according to the needs of the cell
    • Plant cells - Have a large central vacuole, similar to air inside balloon
    • Animal cells - Have many small vacuoles
  • Nucleus
    • Only present in eukaryotic cells
    • Stores and protects DNA
    • Contains nucleolus which produces ribosomes
    • Contains enzymes and DNA to make mRNA for protein synthesis
  • Ribosomes
    • Site of protein synthesis
    • Enzyme that makes proteins using transfer RNA, and from the code on the messenger RNA.
    • Creates peptide bonds between amino acids
    • Mostly located in the ER
  • Peptide Bond
    A type of chemical bond that connects amino acids to form proteins.
  • Rough ER
    • Related to protein synthesis as it is covered with ribosomes
    • Involved in transporting proteins, sent away in vesicles from ER to golgi bodies.
    • Absent in prokaryotes.
  • Smooth ER
    • Makes lipids
    • Degrades fats
    • Detoxifies poisons
    • Inactivates poisons
    • Absent in prokaryotes