TOPIC VIII: CELL PHYSIOLOGY II Flashcards
What two processes are essential for physiological functions?
Protein synthesis and ATP metabolism/cellular respiration. Protein synthesis builds proteins, and ATP metabolism/cellular respiration provides energy.
Define metabolism, anabolism, and catabolism.
Metabolism: Chemical processes performed by cells.
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Anabolism: Building molecules.
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Catabolism: Breakdown of molecules.
Outline the steps of protein synthesis.
Transcription (DNA to mRNA): DNA uncoils, and mRNA forms using the DNA template. For example, if the DNA template is ATC GCA, the mRNA is UAG CGU.
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Translation (mRNA to protein): mRNA associates with ribosomes, and tRNA brings amino acids based on mRNA codons to form a peptide chain. The DNA sequence determines the mRNA sequence, which determines the amino acid sequence.
What happens to proteins after translation?
Proteins made on free ribosomes go to the cytosol, nucleus, or mitochondria. Proteins from the rough endoplasmic reticulum (RER) are modified (glycosylation) in the RER lumen and then go to the Golgi complex in vesicles. The Golgi further modifies proteins (adding carbohydrates or lipids) and packages them for delivery to the cell membrane, secretion, or lysosomes.
Explain ATP catabolism and its purpose.
ATP catabolism is the breakdown of ATP to release energy stored in phosphate bonds. This energy is used for reactions like protein synthesis, active membrane transport, and muscle contraction. The body constantly has to make ATP.
What are enzymes and what are their functions?
Enzymes are proteins that increase reaction rates without being used up. They are sensitive to pH and temperature, which affect their shape and function.
Summarize the process of cellular respiration.
Cellular respiration produces ATP using glucose. Overall: 1 glucose + 6 O2 ⇒ 6 CO2 + 6 H2O + 32 ATP + heat. The steps are glycolysis (anaerobic) in the cytosol, followed by aerobic processes (Krebs Cycle and Electron Transport Chain) in the mitochondria.
What substrates can be used to produce ATP?
Carbohydrates (broken down to glucose), proteins (some amino acids converted to pyruvic acid or enter the Krebs cycle), and fats (broken down to acetyl CoA).
