Test 3 Study Guide Flashcards
Metabolism
All chemical and physical workings of a cell
Two types of chemical reactions, catabolic and anabolic.
Anabolic vs Catabolic
Catabolism - degradative; breaks the bonds of larger molecules forming smaller molecules; releases energy.
Anabolism – biosynthesis; process that forms larger macromolecules from smaller molecules; requires energy input.
Condensation vs Hydrolysis
Condensation involves the formation of a new chemical bond while hydrolysis involves the breakdown of a chemical bond.
Enzymes
Biological catalysts that increase the rate of a chemical reaction by lowering the energy of activation (the resistance to a reaction)
Types of enzymes
Simple enzymes – consist of protein alone
Conjugated enzymes or holoenzymes – contain protein and nonprotein molecules
Apoenzyme – protein portion. Exhibit primary, secondary, tertiary protein organization
Larger enzymes show quaternary structure
Active site (catalytic site): Site for specific substrate binding
Cofactors – nonprotein portion
Inorganic elements.
Metallic Cofactors (metal ions)
Activate enzymes
Help bring the active site and substrate close together
Participate directly in chemical reactions with the enzyme-substrate complex
Coenzymes (organic factors)
Serve as temporary carrier for some substrates
Vitamins as the most common
Aerobic cellular respiration
Series or enzyme-catalyzed reactions in which electrons are
transferred from fuel molecules to oxygen as a final electron
acceptor
• Glycolysis – glucose (6C) is oxidized and split into 2
molecules of pyruvic acid (3C), NADH is generated
• Pyruvate Oxidation
• TCA – processes pyruvic acid and generates 3 CO2
molecules , NADH and FADH2 are generated
• Electron transport chain – accepts electrons from NADH
and FADH; generates energy through sequential redox
reactions called oxidative phosphorylation
Anaerobic respiration
Functions like aerobic respiration except it utilizes oxygen
containing ions, rather than free oxygen, as the final electron
acceptor: NO nitrite and NO Nitrate
Most obligate anaerobes use the H+ generated during
glycolysis and the Kreb’s cycle to reduce some compound
other than O2
glycolysis, the Kreb’s cycle, respiratory chain; molecular oxygen is not the final electron acceptor
Fermentation
Incomplete oxidation of glucose or other carbohydrates in the
absence of oxygen
Uses organic compounds as terminal electron acceptors
Yields a small amount of ATP
Production of ethyl alcohol by yeasts acting on glucose
Formation of acid, gas, and other products by the action of
various bacteria on pyruvic acid
Stages of cellular respiration and reduction
The stages of cellular respiration include glycolysis, pyruvate oxidation, the citric acid or Krebs cycle, and oxidative phosphorylation.
Oxidation vs Reduction
Oxidation is the gain of oxygen, loss of hydrogen. Reduction is the loss of oxygen, gain of hydrogen.
Oxidation occurs when a reactant loses electrons during the reaction. Reduction occurs when a reactant gains electrons during the reaction.
DNA vs RNA
(a) RNA contains the sugar ribose, while DNA contains the slightly different sugar deoxyribose (a type of ribose that lacks one oxygen atom), and (b) RNA has the nucleobase uracil while DNA contains thymine.
Transcription vs translation
Transcription is the synthesis of RNA from a DNA template where the code in the DNA is converted into a complementary RNA code. Translation is the synthesis of a protein from an mRNA template where the code in the mRNA is converted into an amino acid sequence in a protein.
The genetic code and interpretation
Represented by mRNA codons and their specific amino acids
Code is universal among organisms and redundant
Transcription produces mRNA complementary to the DNA gene
During translation, tRNAs use their anticodon to interpret the mRNA codons and bring in the specific amino acids
Chromosome vs gene mutation
Unlike a gene mutation which alters a single gene or larger segment of DNA on a chromosome, chromosome mutations change and impact the entire chromosome.
Examples of genetic recombination events
Genetic recombination – occurs when an organism
acquires and expresses genes that originated in another
organism
3 means for genetic recombination in bacteria:
• Conjugation
• Transformation
• Transduction
Cellular respiration vs Photosynthesis
Photosynthesis converts carbon dioxide and water into oxygen and glucose. Glucose is used as food by the plant and oxygen is a by-product.
Cellular respiration converts oxygen and glucose into water and carbon dioxide.
Stages of photosynthesis
Light-dependent reaction– photons are absorbed by chlorophyll, carotenoid, and phycobilin pigments
Water split by photolysis, releasing O2 gas and provides electrons to drive photophosphorylation
Released light energy used to synthesize ATP and NADPH
Light-independent reaction – dark reactions – Calvin cycle – uses ATP to fix CO2 to ribulose-1,5-bisphosphate and convert it to glucose
ATP Yield for Aerobic Respiration
Glycolysis: 2ATP, 2NADH, 2 Pyruvate
Transition: 2NADH, 2CO2
Krebs Cycle: 4CO2, 6NADH, 2ATP, 2FADH
Electron Transport: 34ATP, 6H20
DNA replication
Making an exact duplicate of the DNA involves 30 different enzymes:
Helicase unwinds and unzips the DNA double helix
An RNA primer is synthesized at the origin of replication by a primase
DNA polymerase III then adds nucleotides in a 5′ to 3′ direction
Leading strand – synthesized continuously in 5′ to 3′ direction
Lagging strand – synthesized 5′ to 3′ in short segments; overall direction is 3′ to 5′; okazaki fragments
DNA polymerase I removes the RNA primers and replaces them with DNA
Glycolysis
Glycolysis is the process of breaking down glucose.
Glycolysis can take place with or without oxygen.
Glycolysis produces two molecules of pyruvate, two molecules of ATP, two molecules of NADH, and two molecules of water.
Glycolysis takes place in the cytoplasm.
Pyruvate Oxidation
Converts pyruvate to Acetyl Coenzyme A and CO2
Makes 2 NADH per cycle in prokaryotes.
Makes 2 FADH2 per cycle in eukaryotes.
Occurs in the cytoplasm in prokaryotes.
Occurs in the mitochondrial matrix in eukaryotes.
Citric Acid Cycle (Krebs Cycle)
Acetyl CoA reacts with oxaloacetate to form citric acids.
Citric acid is oxidized to form oxaloacetate.
Produces 1 ATP per cycle, 2 CO2 per cycle, 3 NADH per cycle, 1 FADH2 per cycle.
ATP synthesis is by substrate level phosphorylation.
Occurs in the cytoplasm of prokaryotes. Occurs in the mitochondrial matrix of eukaryotes.
Electron Transport Chain
Occurs on the plasma membrane of prokaryotes.
Occurs on the inner mitochondrial membrane of eukaryotes.
3 ATP from each NADH, 2 ATP from each FADH2
ATP synthesis occurs by oxidative phosphorylation.
Oxygen is the final electron acceptor in eukaryotes.
