Filling In The Blanks: -Cell theory & 2 types of Cells -Cellular energy -Enzymes effect on Chemical Rxns (AP only)

Learning Objectives: What is Cell Theory How was Cell Theory reached by scientists? (Pre-AP) What is Cell Theory What are some exceptions to Cell Theory Describe in detail how Prokaryotes compare to Eukaryotes What is the job of ATP in cells Why can ATP perform that job

Cell Theory: The Men of the microscopes Pg 170 Anton Van Leeuwenhoek (1600’s) Credited for the first microscope (made ~500) Looked at pond water and saw “wee beasties”

Robert Hooke Observed plant stems, wood, and cork (1600’s) Pg 170 Observed plant stems, wood, and cork (1600’s) Saw all the tiny chambers and called them CELLS What cell part did Hooke observe? Cell Wall

Pg 169

Robert Brown (1833) Observed that cells had a dark structure within plant cells Brown observed the nucleus

Matthias Schleiden (1838) Stated that all plants are made of Cells Pg 171 Stated that all plants are made of Cells Made many observations of plants around the area

Theodor Schwann (1839) Stated that all animals are made of Cells Pg 171 Stated that all animals are made of Cells Observed many animal tissues

Rudolf Virchow (1855) Stated that all cells come from pre-existing cells Cells arise from the division of pre-existing cells

The Cell Theory All living things are composed of cells Cells are the basic unit of structure and function in living things All cells come from pre-existing cells

Exceptions to the Cell Theory Viruses – are not cellular (cannot reproduce on own) Mitochondria and chloroplast – each contain genetic material and can reproduce on their own

Two Types of Cells Prokaryotes Eukaryotes Pg 173 Membrane Cytoplasm EUKARYOTIC CELL PROKARYOTIC CELL DNA (no nucleus) 1 µm Organelles Nucleus (contains DNA)

“So what’s the big diff ?” Pg 173 Prokaryotes Eukaryotes Have NO membrane bound organelles, have Nucleiod region (no true nucleus) Has membrane bound organelles: Nucleus, mitochondria, golgi, ER, & vesicles 1-10 µm (0.000001meters) 10-100 µm (micrometers) smaller BIGGER Structurally simpler Structurally more complex Examples: Bacteria (Eubacteria) Archaea Protists Plants Fungi Animals Unicellular (one-celled) can live in colonies Mostly multicellular (Protists are exception)

Prokaryotes Pg 173

Eukaryotes

But Both Prokaryotes and Eukaryotes can have: cell membrane, cell wall, cytoplasm, ribosomes, DNA & RNA End of Cell Types, Next up: Cell energy

Cellular Energy: what powers a cell? Tip: think of energy as a form of currency (you know…$$$) You can exchange energy to get work done (just like $$$) Adenosine triphosphate (ATP) Pg 203 (don’t try to draw this)

ATP Pg 203 (draw this) Energy is found in the bonds between phosphorus and is released when we break those bonds

ATP = $$$ This energy is used by cells to do: Pg 203 This energy is used by cells to do: Chemical work (chem rxns)** Mechanical work (muscle cells) Transport Work (active transport) (draw just this side) Reactants  Products Before Rxn After Rxn

Two types of chemical reactions Endergonic Reaction: reactants require energy to work to products Reactants + energy  Products Pg 203

Two types of chemical reactions Exergonic Reaction: reactants will release energy as reaction goes to product Reactants  Products + Energy

But what if we could make the EA less of a pain? However ALL reactions require an initial input of energy to get started (even exergonic rxns). Without this initial energy the rxn won’t happen. We call this Activation Energy (EA) So the EA must always be satisfied for a reaction to occur. But what if we could make the EA less of a pain?

A.A. order  protein’s shape  protein’s function Enzyme: A protein (chain of amino acids) that lowers the activation energy of reactions. One specific enzyme for one specific rxn. After the reaction, the enzyme is released and is unchanged, so it can be used many times, and can speed up some rxns by more than a billion times A.A. order  protein’s shape  protein’s function (sound familiar?) Exoergonic Rxn Endergonic Rxn

Enzyme & Substrate fit like a lock & key (Shape specific) pH or temperature can change the active site shape on any enzyme Active site is where the reactants bind to the enzyme END

Speaking of speedy things