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 TheoryThe Cell Theory

Some Random Cell FactsSome Random Cell Facts

The average human being is The average human being is composed of around 100 Trillion composed of around 100 Trillion individual cells!!!individual cells!!!

It would take as many as 50 cells to It would take as many as 50 cells to cover the area of a dot on the letter “cover the area of a dot on the letter “ ii””

WOW!!!WOW!!!

Discovery of CellsDiscovery of Cells

Robert Hooke (1665)Robert Hooke (1665) Discovered cells while looking at a thin slice of Discovered cells while looking at a thin slice of

corkcork.. He described the cells as He described the cells as tiny boxes tiny boxes He thought that cells only existed in plantsHe thought that cells only existed in plants

Anton van LeuwenhoekAnton van Leuwenhoek

1673- Observed single-celled organisms in 1673- Observed single-celled organisms in pond waterpond water

He called them “animalcules”He called them “animalcules” The cells were The cells were livingliving

Therefore, it was knownTherefore, it was known

that cells are found that cells are found

in animals as well as plantsin animals as well as plants

Spirogyra

Development of Cell Development of Cell TheoryTheory

1838- Matthias 1838- Matthias SchleidenSchleiden, concluded that , concluded that all all plant parts are made of cellsplant parts are made of cells

1839- Theodor 1839- Theodor SchwannSchwann, stated that , stated that all all animal tissues are made of cells.animal tissues are made of cells.

Development of Cell Development of Cell TheoryTheory

1858- Rudolf 1858- Rudolf VirchowVirchow (physician) found (physician) found that that cells must arise from preexisting cells must arise from preexisting cells cells while studying disease.while studying disease.

The Cell TheoryThe Cell Theory

HAS 3 PARTS:HAS 3 PARTS:1. All organisms are composed of one or 1. All organisms are composed of one or

more cells. (Schleiden & Schwann)more cells. (Schleiden & Schwann)

2. Cells are the basic units of structure and 2. Cells are the basic units of structure and function in an organism. (Schleiden & function in an organism. (Schleiden & Schwann)Schwann)

3. Cells come only from the reproduction of 3. Cells come only from the reproduction of existing cells. (Virchow)existing cells. (Virchow)

Two Types of Cells

1. ProkaryotesFirst living cellsBacteria and ArchaeaNo organellesNo nucleus

2. EukaryotesAnimals and PlantsOrganellesNucleus

Prokaryotic or Eukaryotic?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 cellsprokaryotic and

eukaryotic have different types

Endoplasmic Reticulum 2 Types:

1.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?

1. Cell Wall2. Vacuole3. 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 CO2 and H2O 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 SizeCell Size

Most cells are 10 to Most cells are 10 to

50µm in diameter 50µm in diameter

Prokaryotes are typically smaller than eukaryotes

YUM….You’re eating an entire cell!

Cell SizeCell Size

The ratio of the surface area to the The ratio of the surface area to the volume limits cell sizevolume limits cell size

Which increases faster, surface Which increases faster, surface area or volume?area or volume?

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

Cell ShapeCell Shape

Different cells have different Different cells have different shapes based on functionshapes based on function