Cellular Respiration & Protein Synthesis

1. Cellular Respiration & Protein Synthesis

2. 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

3. 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

5. 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

7. Metabolic Pathway

8. 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

9. 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)

10. 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.

11. 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

12. Phosphorylation: ADP + Phosphate + Energy → ATP • Hydrolysis: ATP → ATP + Phosphate + Energy

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

14. 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

15. 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

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

18. 2. Synthesis of Acetyl CoA • 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

20. 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

22. 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

24. Protein SynthesisDNA →transcription→ RNA → translation → Proteins

25. 4 Nitrogenous bases • Purines: Adenine (A) Guinine (G) • Pyrimidines: Thymine (T) Cytosine (C) • Complimentary Base Pairs • A pairs with T • C pairs with G

27. 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

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

30. 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

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

33. TranslationmRNA→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