Biology The Study of Living Organisms

What is Living? Use Energy Metabolism Develop and Grow Homeostasis Maintain themselves Reproduction Asexual – reproduction by yourself Sexual reproduction Evolve Made of Cells

Macromolecules Large molecules made of smaller molecules linked together Four Major Types: Protein Carbohydrates Lipids Nucleic Acids

Macromolecules Protein Subunit: amino acids 20 amino acids in living organisms Skin, hair, feathers, insulin, hemoglobin, antibodies, enzymes

Macromolecules Carbohydrates Subunits: Saccharides (sugars) Starch, glycogen, cellulose

Macromolcules Lipids Fatty acid + carboxyl group Used for long term energy storage Fats, oils

Macromolecules Nucleic Acids Subunit: Nucleotide DNA and RNA Store Genetic Information

The Cell Theory The Cell Theory

Some Random Cell Facts The average human being is composed of around 100 Trillion individual cells!!! The average human being is composed of around 100 Trillion individual cells!!! It would take as many as 50 cells to cover the area of a dot on the letter “ i ” It would take as many as 50 cells to cover the area of a dot on the letter “ i ”WOW!!!

Discovery of Cells Robert Hooke (1665) Robert Hooke (1665) Discovered cells while looking at a thin slice of cork. Discovered cells while looking at a thin slice of cork. He described the cells as tiny boxes He described the cells as tiny boxes He thought that cells only existed in plants He thought that cells only existed in plants

Anton van Leuwenhoek Observed single-celled organisms in pond water Observed single-celled organisms in pond water He called them “animalcules” He called them “animalcules” The cells were living The cells were living Therefore, it was known that cells are found that cells are found in animals as well as plants Spirogyra

Development of Cell Theory Matthias Schleiden, concluded that all plant parts are made of cells Matthias Schleiden, concluded that all plant parts are made of cells Theodor Schwann, stated that all animal tissues are made of cells Theodor Schwann, stated that all animal tissues are made of cells.

Development of Cell Theory Rudolf Virchow (physician) found that cells must arise from preexisting cells while studying disease Rudolf Virchow (physician) found that cells must arise from preexisting cells while studying disease.

The Cell Theory HAS 3 PARTS: HAS 3 PARTS: 1. All organisms are composed of one or more cells. (Schleiden & Schwann) 2. Cells are the basic units of structure and function in an organism. (Schleiden & Schwann) 3. Cells come only from the reproduction of existing cells. (Virchow)

Two Types of Cells Prokaryotes First living cells Bacteria and Archaea No organelles No nucleus Eukaryotes Animals and Plants Organelles Nucleus

Prokaryotic or Eukaryotic?

Cell Parts Membrane and Wall Genetic Material Organelles Structures that perform specific functions in the cell

Cell Membrane Selectively permeable phospholipid bilayer Found in prokaryotes and eukaryotes

Nucleus Nickname: “The Control Center” Function: holds the DNA

Mitochondria Nickname: “The Powerhouse” Function: Energy formation Breaks down food to make ATP – –ATP: is the major fuel for all cell activities that require energy

Mitochondria Mitochondrial DNA Ancient Eukaryotic cell ate a prokaryotic cell

Ribosomes Function: makes proteins out of Amino Acids Found in all cells prokaryotic and eukaryotic have different types

Endoplasmic Reticulum 2 Types: Rough ER: – –Ribosomes on surface – –Function: helps make proteins and phospholipids

Endoplasmic Reticulum 2 Types: 2. Smooth ER: – –NO ribosomes – –Function: makes fats or lipids, breaks down drugs

Golgi Apparatus Nickname: The Post Office Function: packages, modifies, and transports materials to inside/outside of the cell

Lysosomes Nickname: “Clean-up Crews” Function: Digest food particles, waste, cell parts, and foreign invaders Have lower pH and special enzymes

Cytoskeleton Gives Cells Shape and Support Microtubules Intermediate Filaments Microfilaments

Cilia and Flagella Both help with cell movement Cilia Short Hairlike numerous Flagella Long One or two per cell

What do Plant Cells Have? Cell Wall Vacuole Chloroplasts Pine Needle

Plant Cell Cell Wall Outside of plasma membrane Made of cellulose

Plant Cell Vacuole Stores water, waste, enzymes Can make up 90% of plant cell volume Causes plant to stand upright

Plant Cell Chloroplasts Make carbohydrates from CO 2 and H 2 O using light energy Contain Thylakoids with chlorophyll

Animal Cell vs. Plant Cell

Cell Membrane Hydrophobic and Hydrophilic Membrane Proteins Communication Join cells together Control transport across membrane Carbohydrates Allow cells to recognize each other Fluid Mosaic Model Phospholipids and proteins can slide past each other

Transport Across Membrane Diffusion Tendency of molecules to move from high concentration to low concentration Osmosis Diffusion of water Works for small hydrophobic molecules

Transport Across Membrane Facilitated Diffusion Ions and large molecules cannot pass freely across the membrane Carrier proteins Allow molecules to move down the concentration gradient NO ENERGY NEEDED! Passive Transport

Transport Across Membrane Active Transport Carrier proteins move molecules AGAINST the concentration gradient Requires energy

Transport Across Membrane Endocytosis Portion of membrane folds inward and pinches off

Transport Across Membrane Exocytosis Vesicle fuses with membrane and dumps contents outside

Cell Size Most cells are 10 to Most cells are 10 to 50µm in diameter

Prokaryotes are typically smaller than eukaryotes

YUM….You’re eating an entire cell!

Cell Size The ratio of the surface area to the volume limits cell size The ratio of the surface area to the volume limits cell size Which increases faster, surface area or volume? Which increases faster, surface area or volume?

Why would having a low surface area to volume ratio be important?

Cell Shape Different cells have different shapes based on function Different cells have different shapes based on function