Introduction to Cell Physiology Slides by John R. Waters, Anatomy and Physiology at Penn State available at: Everything/powerpoint/All_the_intro_concepts_S ummerB/

What is physiology? The branch of biology dealing with the functions and activities of living organisms and their parts. The study of bodily function that primarily employs the methods of experimental science.

Biological Organization (pg.17) A hierarchy of structural complexity The organism,

Biological Organization (pg.17) A hierarchy of structural complexity The organism is composed of organ systems

Biological Organization (pg.17) A hierarchy of structural complexity The organism is composed of organ systems organs systems are composed of organs,

Biological Organization (pg.17) A hierarchy of structural complexity The organism is composed of organ systems organs systems are composed of organs, organs are composed of tissues,

Biological Organization (pg.17) A hierarchy of structural complexity The organism is composed of organ systems organs systems are composed of organs, organs are composed of tissues, tissues are composed of cells,

Biological Organization (pg.17) A hierarchy of structural complexity The organism is composed of organ systems organs systems are composed of organs, organs are composed of tissues, tissues are composed of cells, cells are composed partially of organelles,

Biological Organization (pg.17) A hierarchy of structural complexity The organism is composed of organ systems organs systems are composed of organs, organs are composed of tissues, tissues are composed of cells, cells are composed partially of organelles, organelles are composed of molecules,

Biological Organization (pg.17) A hierarchy of structural complexity The organism is composed of organ systems organs systems are composed of organs, organs are composed of tissues, tissues are composed of cells, cells are composed partially of organelles, organelles are composed of molecules, molecules are composed of atoms,

Biological Organization (pg.17) A hierarchy of structural complexity The organism is composed of organ systems organs systems are composed of organs, organs are composed of tissues, tissues are composed of cells, cells are composed partially of organelles, organelles are composed of molecules, molecules are composed of atoms, and atoms are composed of subatomic particles

Atomic Structure (52-54) Element –a substance that cannot be broken down into simpler substances air - not an element –nitrogen, oxygen, carbon dioxide »carbon dioxide (carbon and oxygen) sugar - not an element –carbon, hydrogen, and oxygen table salt - not an element –sodium and iodide (sea salt = sodium and chloride) Atom –the smallest component of an element, that still has the chemical properties of that element

Up 1 up 2 Atomic Structure (52-54) Atom –the smallest component of an element, that still has the chemical properties of that element

Carbon Atomic Structure (52-54) Atom –made up of 3 types of subatomic particles protons (positive charge) neutrons (no charge) electrons (negative charge) back

–the number of these determines the identity of the atom (element) –add weight to the atom, but do not change the identity of the atom (element) –swarm around the nucleus, determine the charge of the atom »equal number of electrons and protons (NO CHARGE) »add electrons so there are more electrons than protons (NEGATIVE CHARGE) »remove electrons so there are fewer electrons than protons (POSITIVE CHARGE) –Any atom with a charge is called an ion ions can be positively or negatively charged Atomic Structure (52-54) Atom –made up of 3 types of subatomic particles protons (positive charge) neutrons (no charge) electrons (negative charge) Carbon Nucleus

Chemical Bonds (58-60) Atoms can be bound together to form molecules –2 H + + O --  H 2 O (water) –Na + + Cl -  NaCl (sodium chloride) –6 C + 12 H O --  C 6 H 12 O 6 (carbohydrate)

Chemical Bonds (58-60) The atoms that form molecules are bound together by chemical bonds –covalent bond electrons shared between atoms –single (C-C) –double (C=C) –non-polar (C-C) –polar (O-H) »water –ionic bond oppositely charged ions are attracted to one another –NaCl –hydrogen bond weak bond between a slightly positive hydrogen and a slightly negative oxygen or nitrogen O HH - +

Chemical Bonds - hydrogen bonds (58-60) –hydrogen bond weak bond between a slightly positive hydrogen and a slightly negative oxygen or nitrogen O HH - +

Electrolytes (54-56) Any molecule that becomes an ion in water is an electrolyte. –NaCl  Na + and Cl - –H 2 CO 3  H + and HCO 3 - –K + and Ca ++ also very common

Molecules and chemical reactions (66, 68) Chemical bonds between molecules can be formed or broken during chemical reactions Metabolism is all of the chemical reactions occurring in your body –catabolism (breaking down a molecule) energy released during chemical reaction EX. carbohydrates are broken down to release energy –anabolism (synthesizing or building a molecule) energy required for chemical rxn EX. energy is used to build proteins or make ATP.

Molecules and chemical reactions – ATP (96-97) ATP (adenosine triphosphate) is a molecule synthesized by organisms to store energy in a readily usable form. The energy is stored in the chemical bonds of ATP molecules as chemical potential energy –ADP + P + energy -> ATP This energy can be used by cells whenever they need to do work. –ATP -> ADP + P + energy

Molecules and chemical reactions – ATP (96-97)

Life requires about 25 chemical elements 96% of living matter is made up of –C–C –O–O –N–N –H–H the other 4% is mostly P, S, Ca, and K plus some trace elements like Fe and I

Most macromolecules are polymers (80) Monomers are basic subunits used to build polymers (smaller molecules) (larger molecules) –We will focus today on two polymers lipids proteins

Lipids are mostly hydrophobic molecules with diverse functions (85-87) Fats

Lipids are mostly hydrophobic molecules with diverse functions (85-87) Phospholipids

Lipids are mostly hydrophobic molecules with diverse functions (85-87) Phospholipids form stable structures in water

Proteins (87-92) Proteins are the molecular tools for most cellular functions A protein is a polymer of amino acids connected in a specific sequence N H CC H O OH H R1R1 N H CC H O H R2R2

Proteins (87-92) Proteins are the molecular tools for most cellular functions A polypeptide is a polymer of amino acids connected in a specific sequence N H CC H O OH H R1R1 N H CC H O H R2R2 + N H R1R1 CC H OH N H R2R2 CC O H HOH +

Proteins (87-92) Proteins are the molecular tools for most cellular functions A polypeptide is a polymer of amino acids connected in a specific sequence 20 different amino acids (aa) Each aa has a different R group

Proteins (87-92) Proteins are the molecular tools for most cellular functions A polypeptide is a polymer of amino acids connected in a specific sequence 20 different amino acids (aa) Each aa has a different R group –Polar (+ or - charge) hydrophilic

Proteins (87-92) Proteins are the molecular tools for most cellular functions A polypeptide is a polymer of amino acids connected in a specific sequence 20 different amino acids (aa) Each aa has a different R group –Polar (+ or - charge) hydrophilic –Non-polar (no charge) hydrophobic –hydrogen, ionic, covalent bonds between R groups are also possible

Proteins (87-92) A protein’s function depends on its specific conformation –primary structure –secondary structure –tertiary structure –quaternary structure Proteins are the molecular tools for most cellular functions A polypeptide is a polymer of amino acids connected in a specific sequence

A molecule’s biological function is related to its shape Remember….

A protein’s function depends on its specific conformation

Review

Biochemical Example of Feedback Control Input(Glucose) X 0 X 1 X i X n …… Output (ATP) perturbation Negative Feedback Glycolysis: a metabolic pathway X_i : metabolites (small molecules derived from glucose) : chemical reactions (each catalyzed by an enzyme)

Enzyme-Catalysed Reactions enzyme_substrate.gif

Allosteric Regulation

A Regulated Enzyme: Phosphofructokinase (PFK) Effector: Product: Reactants:

How can biochemicals regulate enzyme activity? By inducing conformational changes

Nucleic acids store and transmit hereditary information

A DNA strand is a polymer with an information-rich sequence of nucleotides

The DNA strand is a double helix

Central Dogma

DNA (deoxyribonucleic acid) Chain composed of bases: A, C, G, T

Some segments of DNA code for proteins Other segments of DNA code for RNAs (e.g. tRNAs or rRNAs.)

Still other segments of DNA are regulatory regions. RepressionActivation

Basic structure of a cell ( ) plasma membrane cytoplasm –organelles vesicles mitochondria nucleus many others –proteins structural enzymes

Basic structure of a cell - plasma membrane ( ) lipid bilayer membrane proteins –gates/pores –pumps –receptors Plasma membranes will let some things pass, but not others They are semipermeable

Carrier mediated transport ( ) Requires membrane proteins Two types of carrier mediated transport –facilitated diffusion proteins channels just act as doors just diffusion no energy required –active transport substances move against their concentration gradient move from an area of low concentration... to an area of high concentration Requires ENERGY ATP

Carrier mediated transport ( ) Requires membrane proteins Two types –facilitated diffusion –active transport substances move against their concentration gradient move from an area of low concentration... to an area of high concentration Requires ENERGY

Active Transport Review ( )