M I D T E R M 25 multiple choice 6 short answer questions one bonus Chapter 25 Metabolism Refers to all the chemical reactions that take place in an Functions metabolic turnover growth and cell division and organism special processes o Catabolism breakdown of organic substrates releases energy that can be used to synthesize ATP o Anabolism synthesis of new organic molecules to carry out structural maintenance for support and growth to produce secretions and to store nutrient reserves o Aerobic Cellular Respiration use of oxygen to produce energy o Anaerobic Cellular Respiration without oxygen to produce for cellular use energy for cellular use o Cellular respiration oxidation of organic compounds that occurs within cells producing energy for cellular purposes Three steps in Aerobic Cellular Respiration Glycolysis Where Cytoplasm What breakdown of glucose 6 carbon chain Glucose split in half to create 2 pyruvates 3 carbon chain One carbon from each pyruvate splits off to bond with oxygen to create CO2 which leaves the cell intermediate step Energy Gain 2 ATP 2 NDH EVERYTHING IN 2 S No oxygen O2 involved The intermediate step is going to occur in the intermembrane space of the mitochondria each pyruvate loses carbon and oxygen in form of carbon dioxide decarboxylation 2 Krebs Citric Acid Cycle Where Mitochondrial matrix Starts off with 1 Acetyl CoA that will bind with a 4 carbon molecule oxaloacetate to form Citric acid Acetyl CoA needs the 4 carbon molecule to regenerate Cycle goes around twice for 2 Acetyl CoA s from glycolysis Energy Gain per cycle 1 ATP 3 NADH 1 FADH2 2 CO2 from intermediate step Energy gain TOTAL 2 ATP used in cell for energy 6 NADH and 2 FADH2 are used for the electric transport chain 4 CO2 breathed out 3 Electric Transport Chain Where along intermembrane space Chain of 3 protein complexes ATP Synthase For each electron that is transported to the next protein complex one hydrogen ion is pumped from the mitochondrial matrix into the intermembrane space On the third and final protein complex combustion takes place 4 electrons 4 hydrogen ions and an oxygen molecule meet inside the protein complex and creates a water molecule which is pumped back into the mitochondrial matrix and the 4 hydrogen atoms are pumped into the intermembrane space ATP Synthesis is the last step and can only occur when there is a high hydrogen ion concentration gradient created by the hydrogen pumping steps throughout protein complexes In order to create 1 ATP 3 Hydrogen ions have to enter the mitochondrial matrix through ATP synthesis ADP and Pi floating around in the matrix come together to form ATP oxidative phosphorylation Energy Gain 32 ATP O I L R I G Oxidation is losing e NADH NAD FADH2 FAD Reduction is gaining e NAD NADH FAD FADH2 36 molecules of ATP is created collectively during the entire cellular respiration process 2 from glycolysis 2 from citric acid cycle 32 from electric transport chain In anaerobic cellular respiration lactic acid fermentation occurs Chapter 5 Stanfield Intracellular Communication o Source cell secretory cell o Target cell has receptors for and responds to messenger 2 mechanisms of intercellular communication 1 Direct Connexon physically links the cells together core allows molecules to go from one cell to the other Gap Junctions Composed of membrane proteins connexon Link cytosol of 2 adjacent cells Particle movement between cells acts as signal 2 Indirect chemical messengers Presence of chemical messengers produced from secreting cells which are transported to target and binds to a receptor which triggers a target cell response Source cell Ligand Target cell A chemical messenger is also called a ligand and will always bong to a receptor protein Classified by function or chemical properties solubility properties and chemical class Chemical Messenger Classification by Function 1 Paracrine Chemical Messenger Chemical that serves to signal to a neighboring cell Produced in secretory cell Ex Histamine 2 Autocrine Subclass of paracrines Produced in secretory cell but then loops back to a receptor on the same secretory cell Source and target cell are the same 3 Neurotransmitter A ligand Messenger produced by neurons Released into ECF in synaptic cleft Synapse Synaptic cleft in between the presynaptic and postsynaptic cells Ex Glycine Acetlycholine serotonin 4 Hormone Messenger produces in endocrine cells Endocrine cells are the source cells for hormones with a number of target cells Secreted into the blood via ISF Ex Insulin estrogen thyroxin 5 Neurohormone Special class of hormone messenger produced by neurons Also secreted into the blood via ISF Ex Oxytocin ADH Chemical Messenger Classification by Solubility 1 Lipophobic Ligand Fear of fat Not lipid soluble does not cross cell membrane easily may require pumps or channels Water soluble Receptors are on cell membranes General action of target response Enzyme activation Membrane permeability changes 2 Lipophilic Ligand Love Fat Lipid soluble not water soluble Easily crosses membrane Target cell has intracellular location General action of target response Gene activation Chemical Messenger Classification by Chemical Class chart on ppt 1 Amino Acids Lipophobic target cells on cell membrane Only 4 amino acids functions as messengers 4 amino acids functions a neurotransmitters Ex Glutamate aspartate glycine GABA 2 Amines Lipophobic except thyroid hormones Target cells on cell membrane Derived from amino acids contains amine group Ex Catecholamines Derived from tyrosine Ex Dopamine Norepinephrine epinephrine More examples Thyroid hormones derived from 2 tyrosine amino acids Histamine derived from histadine Serotonin derived from tryptophan 3 Peptide and protein messengers Most abundant type of ligand Lipophobic target receptors on cell membrane Made of chain of amino acids Peptide ligand 50 amino acids Protein ligand 50 amino acids 4 Steroid Ligands Lipophilic intracellular target receptors Derived from cholesterol All steroid ligands function as hormones 5 Eicosanoid Ligands Lipophilic intracellular target receptors Derived from arachidonic acid a cell membrane phosphilipid Messenger Transport How ligands get around Diffusion through interstitial fluid o Source cell and target cell are close o Ligand is quickly degraded o Ex Paracrines Autocrines Neurotransmitters and most cytokines Blood Bourne Transport o Source cell and Target cell at distance o Lipophilic Chemical Messengers Hydrophobic messenger Bind to