CellsBiology

Discovery of Cells

•Robert Hooke-1665▫Biologist, inventor, architect

physicist, astronomer▫30x, cork…cells

•Anton van Leeuwenhoek▫300x, single-celled organisms

• Introduction - http://www.youtube.com/watch?v=zufaN_aetZI

Cell Theory

•Developed around 1800▫All living things are made up of one or

more cells▫The cell is the smallest unit that still

retains the characteristics of life▫All cells arise from existing cells

Cell Size & Shape

•A larger cell would:▫Take up more nutrients▫Excrete more waste▫Have difficulty transporting nutrients &

waste•Potato Demo

•Shape determines function▫Larger cells = more surface area

Features of All Cells…

•Cell membrane▫Transport (barrier), communicate, identify,

etc. •Cytoplasm

▫Inner fluid & suspended organelles•Ribosome

▫Makes protein•DNA

▫Instruct making of protein, regulates cell activities, & allows cells to reproduce

Prokaryotic Cells

•Single cell, ~ 3.5 bya•Lacks

▫Nucleus ▫Membrane bound

organelles•Has

▫DNA in a single loop…nucleoid

▫Cytoplasm, enzymes▫Ribosomes▫Cell wall, some have

capsule

Bacteria Growth: http://www.youtube.com/watch?v=gEwzDydciWc&NR=1

Eukaryotic Cells• Some single-celled • All multi-celled• ~1.5 bya• More complex

▫Specialized functions• Lacks:

▫Capsule• Has:

▫Nucleus=a membrane bound organelle that contains DNA, directs cell functions

▫Membrane bound organelles=one of the small bodies that are found in the cytoplasm of a cell and that are specialized to perform a specific function

▫Among others

The Cytoskeleton

•Eukaryotes▫Protein fibers▫Move cells▫Provides structure

Shape

Amoeba Moving: http://www.youtube.com/watch?v=7pR7TNzJ_pA

Making Proteins…

•Extremely important!•DNA=Permanent instructions, nucleus•RNA=Copied instructions, goes to

cytoplasm•Ribosomes=Use RNA to make protein•Endoplasmic reticulum=packages

protein•Golgi apparatus=proteins (and other

cell products) are modified, sorted, & shipped▫To cell membrane, using vesicles

Storage & Maintenance

•Maintain homeostasis•Lysosome=use enzymes to break down

waste▫What are enzymes?

•Vacuole=storage of water, nutrients, waste, etc.

•Central vacuole=plantsTurgor Pressure: http://www.youtube.com/watch?v=V56Zy7uLFEAhttp://www.youtube.com/watch?v=lz

DlGl3b4is&feature=related

Energy Production

•Chloroplasts (plant cells)▫Sugar production, stores energy in

chemical bonds From light energy, water, & CO2 Process called?

•Mitochondria (plant & animal cells)▫Converts stored energy to ATP

From sugar Process called?

Cell Membrane• Homeostasis

▫Stable internal conditions in a changing environment• Break down the words…• Phospholipid bilayer

▫Hydrophobic tails (polar or nonpolar?)▫Hydrophilic heads (polar or nonpolar?)

• 4 types of proteins: 1 Cell Surface Markers 2 Receptor Proteins 3 Enzymes 4 Transport Proteins

• Osmosis vs. Diffusion

Osmosis•Transport of water•Solutions: Hyper-(more), Iso-, & Hypo-

(less)

Diffusion

•Transport of molecules/particles▫Passive transport (no energy)

Osmosis Simple diffusion Facilitated diffusion (channel/carrier proteins)

▫Active transport (needs energy) Pumps (e.g. sodium potassium pump) Vesicles (endocytosis & exocytosis)

Microscopes & How They Work

•Necessary to study cells•2 major categories

▫Light microscopes Convex glass

▫Electron microscopes

Using Light Microscopes…

•Set up:▫Carry with one hand on base and one

around arm▫Put coverslip on slide, if needed▫Observe specimen on lowest power first▫Magnify to higher power as needed

Note: as you magnify image, you see less area on slide

▫Clean lenses & slides with chemwipes▫Put away