Unit 3: Cell Structure & Function Mrs. Howland Biology Level 10 Rev. Oct 2015

All living things are made up of …  What is the smallest part of a LIVING thing?

Cell Theory  All living things are made up of CELLS  CELLS are the basic units of structure and function in living things.  New cells are produced from existing cells

The DISCOVERY of cells  In the 1600s, scientists began using microscopes  Robert Hook looked at cork (plant material), discovering small ‘chambers’ he called CELLS (named after the tiny rooms they resembled!!)

Discovery of BACTERIA  Anton van Leeuwenhoek looked at pond water and a sample taken from a human mouth  This was his drawing of the organisms he saw in the mouth—these are the organisms we call BACTERIA! Check out his microscope!

CELL TYPES & SIZES

Prokaryotes vs. Eukaryotes We categorize cells into TWO basic types

Prokaryotes  Do NOT enclose DNA in nuclei  SMALLER, and SIMPLER structure  Still grow, respond to environment, can move, have genetic material in form of DNA  BACTERIA!

Eukaryotes  LARGER and MORE COMPLEX structures  Highly SPECIALIZED  CONTAIN internal structures and organelles  Plant cells, animal cells, fungi, protists

Cell is like a FACTORY or CITY Each part has its own function. Together, the parts work to maintain life.

The “JOB” of a cell  What jobs do cells have to do for an organism to live…  “Breathe” ~ gas exchange: O 2 in vs. CO 2 out  Eat ~ take in & digest food  Make energy ~ ATP  Build molecules ~ proteins, carbohydrates, fats, nucleic acids  Remove wastes ~ byproducts of chemical reactions, dead bacteria/viruses/cells  Control internal conditions ~ homeostasis!!!  Respond to external environment  Build more cells ~ growth, repair, reproduction & development

Organelles  Organelles are structures inside cells  They do the “WORK” of cells  Are specialized by function

Cell Parts and Functions

Cell Membrane  Protects and supports the cell  Semi-permeable ~ Lets things in and out of the cell  Location: around the cell

Cell Parts and Functions Nucleus  “Control center” ~ contains DNA  Location: inside the cell, near the center near the centerChromatin  Strands of information ~ ‘instructions’ for the cell  Location: inside the nucleus

Cell Parts and Functions Nucleolus (Nucleoli)  Makes ribosomes  Location: inside the nucleus (dark spot) (dark spot) Nuclear Membrane  Protects nucleus  Lets things in/out of nucleus (pores)  Location: around nucleus cell

Cell Parts and Functions Mitochondria  Uses food to make chemical energy in the form of ATP  “powerhouse”  Location: in cytoplasm Golgi Bodies/Apparatus  Modifies, sorts, packages proteins and lipids for transport out of the cell  (Location: in cytoplasm

Cell Parts and Functions Endoplasmic Reticulum (E.R.)  Assembles proteins and lipids  Two types: SMOOTH and ROUGH (has ribosomes)  Location: attaches from cell membrane to nuclear membrane Rough E.R.

Cell Parts and Functions Ribosome  Synthesizes proteins  Location: in cytoplasm or  Attached to E.R.

Cell Parts and Functions Vesicle  Membrane-bound sac  Holds/transports materials Vacuole  Stores food and water  Location: in cytoplasm

Cell Parts and Functions Lysosome  Use chemicals ~ ENZYMES ~ to LYSE (break apart) food molecules and old cells

Cell Parts and Functions Cytoplasm  Gel-like substances, holds all organelles in cell  Location: in cell Cytoskeleton  Maintains cell shape, moves cell parts, helps cells move  Actin, tubulin  Prokaryotes have protein filaments  Location: in cell

Cell Parts and Functions Cilia  Short hair-like projections  Used for movement  Location: outside of cell Flagella  Long whip-like tail  Used for movement  Location: outside of cell

Cell Structures and Functions Chloroplast  Traps sun’s energy and makes food  Location: in plant cells

Cell Parts and Functions Cell Wall  Protects and supports plant  Cells  Prevents water loss  Cellulose  Location: outer layer of plant cells

Cells and Microscopy

Cells and Microscopy ~ Plant Cells Onion Cells at 400x Onion Cells at 100x

Cells and Microscopy ~ ANIMAL CELL Cheek Cells at 400x

Cells and Microscopy ~ ANIMAL CELL Muscle Cells at 100x

CELL TRANSPORT Movement of molecules into and out of the cell

PASSIVE TRANSPORT- Diffusion  Does NOT require energy  Molecules move from HIGHER concentration to LOWER concentration

PASSIVE TRANSPORT- Osmosis  Facilitated diffusion – requires protein channels  Water moves across membrane until dynamic equilibrium is reached

Different Concentrations inside and outside cells…  HYPERTONIC ~ Solution outside of cell has GREATER concentration of particles. Water moves OUT of cell.  ISOTONIC ~ Solution outside of cell and inside of cell have equal concentrations. Water moves equally in both directions.  HYPOTONIC ~ Solution outside of cell has LOWER concentration of particles. Water move INTO cell.

Effects of Osmosis on Animal Cells

ACTIVE TRANSPORT- Requires energy!!  Protein pumps – ATP energy pumps small molecules  Exocytosis – Sending material OUT of the cell (BULK TRANSPORT)  Endocytosis – Taking material INTO the cell (BULK TRANSPORT)

ACTIVE TRANSPORT- Requires ENERGY!!!