Cellular Respiration & Protein Synthesis

Anabolism Anabolism (add) Large molecules are synthesized from smaller molecules Dehydration Synthesis – H2O is released when bonds are formed Connects monosaccharides to form polysaccharides Connects fatty acids to glycerol Joins nucleotides together Joins amino acids together = peptide bonds

Catabolism Catabolism (cut) Reverse of anabolism Large molecules are broken down into smaller molecules Hydrolysis reaction – requires H2O to break molecules Breaks down polysaccharides into monosaccharides & disaccharides Removes fatty acids from glycerol Breaks down polypeptides into amino acids Breaks down nucleic acids into nucleotides

Requirements for reactions Activation energy Energy needed to start a reaction-may be heat Enzymes Characteristics of enzymes Almost always proteins Catalyze (speed up) reactions Reusable-not consumed by reaction Anabolic & catabolic reactions require different enzymes Specificity- each enzyme acts only on one molecule or substance End in ___ase Examples: Lipase digests lipids Protease digests proteins

Metabolic Pathway

Energy Energy = capacity to change something, or to do work Examples of energy: heat, sound, light, electrical, chemical, mechanical Energy cannot be created or destroyed. Only changed or transferred

Adenosine Triphosphate (ATP) Currency of energy for cells Nucleotide with 3 high energy phosphate bonds Phosphate bond can be broken, releasing energy for cell • Hydrolysis reaction releases Phosphate & transfers energy • Product = Adenosine Diphosphate (ADP)

IMPORTANT PROCESS Cellular Respiration Transfer of energy from chemical bonds of molecules to make available for cellular use Oxidation reaction- controlled burning of molecules. Chemical bonds are broken releasing energy. Energy is used by cells.

Through CELLULAR RESPIRATION Phosphate bond can be added to ADP to reuse ATP Phosphorylation = adding phosphate to ADP Requires energy to add Phosphate to ADP Makes ATP reusable

Phosphorylation: ADP + Phosphate + Energy → ATP Hydrolysis: ATP → ATP + Phosphate + Energy

Cellular Respiration Anaerobic Aerobic Does not require Oxygen Makes only little energy (ATP) Aerobic Requires Oxygen Makes more energy (ATP)

Steps of Respiration Glycolysis Conversion of pyruvate into Acetyl CoA Citric Acid Cycle Electron Transport Chain What you’ll need to know: The order they occur Does it require oxygen? Where is the reaction? What do you start with and what do you end with in each reaction step Which one creates the most ATP

Electron Carrier Molecules NAD+ + 2H: → NADH: + H+ (NADH: carries electrons) FADH2 FAD + 2H: → FADH2: (FADH2: carries electrons) NADH & FADH2 carry electrons from metabolic reactions to electron transport chain

1.Glycolysis Breaking of glucose Occurs in cytosol Anaerobic Yields: 2 ATP (net gain) 1 NADH molecule 2 Pyruvic Acids

2. Synthesis of Acetyl CoA Aerobic Reaction Occurs within Mitochondria Primes 3 Carbon Pyruvic Acid for Citric Acid Cycle Reaction 3 Carbon Pyruvic Acid is decomposed into 2 Carbon Acetic Acid Releases 1 CO2 molecule as waste Releases 1 NADH molecule (carries 2 electrons to ETC) Acetic Acid synthesizes with Coenzyme A (CoA) → Acetyl CoA Acetyl CoA = substrate for Citric Acid Cycle

3. Citric Acid Cycle or Kreb Cycle Aerobic Reaction Occurs within Mitochondria Begins & ends with Oxaloacetic Acid 8-9 total reactions involved Reaction Oxaloacetic Acid (4 Carbon) + Acetyl CoA (2 Carbon) → Citric Acid (6 Carbon) Citric Acid is converted to new Oxaloacetic Acid in a series of reactions Oxaloacetic Acid is used in the next Citric Acid cycle Yields 2 CO2 waste 1 ATP 3 NADH 1 FADH2 3 NADH + 1 FADH2 = carries 8 electrons to electron transport chain

4. Electron Transport Chain Occurs on inner mitochondrial membrane Cristae = folding of inner membrane Requires Oxygen as final electron acceptor Involves 4 Proteins 3 Transport Chain Complex Proteins Powered by e- transfer from NADH or FADH2 Uses energy from e- transfer to power ATP Synthase ATP synthase Enzyme Converts ADP + Phosphate → ATP Obtains energy from Transport Chain Complexes

Protein Synthesis DNA →transcription→ RNA → translation → Proteins

4 Nitrogenous bases Purines: Adenine (A) Guinine (G) Pyrimidines: Thymine (T) Cytosine (C) Complimentary Base Pairs A pairs with T C pairs with G

Creates a copy of DNA molecule Occurs within Nucleus DNA Replication Creates a copy of DNA molecule Occurs within Nucleus DNA must unwind & separate Catalyzed by DNA polymerase DNA polymerase uses one strand of DNA as template & adds a new 2nd DNA strand Semiconservative = half of replicated DNA is new, half is original DNA Steps H bonds break & DNA strands separate DNA Polymerase adds new DNA strand to template Yields 2 new DNA strands from 1

Ribonucleic Acid (RNA) Single Stranded Bases: Adenine (A) Uracil (U) Cytosine (C) Guinine (G) Uracil Replaces Thymine. A & U are Complimentary base pairs

Transcription DNA→RNA Messenger RNA (mRNA) is transcribed from DNA Steps Hydrogen bonds of DNA break & strands separate RNA Polymerase builds mRNA using DNA as template mRNA transcript is transported to ribosomes in cytoplasm Video

Codon = 3 bases code for 1 amino acid mRNA transcript Begins with AUG Codon = 3 bases code for 1 amino acid GGG = glycine AUG = methionine

Translation mRNA→protein Occurs on ribosomes in cytosol Ribosome = ribosomal RNA + protein Transfer RNA (tRNA) carries amino acids to mRNA on ribosomes Anticodons on tRNA bind to codons on mRNA Sequence of codons on mRNA determines amino acid sequence Ribosomes link amino acids together by peptide bonds tRNA releases amino acid & picks up another amino acid Video