Biology- AAMC FLASH CARDS fully solved 2023 verified

Biology- AAMC FLASH CARDS fully solved 2023 verified An organism is likely to be a bacterium rather than a virus if it a. Reproduces via fission b. Has a rigid outer covering c. lacks a nuclear membrane d. contains both RNA and protein - correct answer A. Reproduces via fission Why: Viruses reproduces by replicating within a host cell and thus cannot reproduce via fission as bacteria do. HIV is a retrovirus , an RNA virus that can insert itself into the human genome. This virus can reproduce in host cell because it contains: a. Enzymes that destroy T cells b. Viral DNA that is compatible with human DNA C. Core proteins rather than DNA D. Reverse transcriptase - correct answer D. Reverse transcriptase Why: Question states that HIV is a retrovirus and for a virus to reproduce itself it needs a host cell, it's RNA must be converted to DNA which requires the enzyme reverse transcriptase. A wound that penetrates the rib cage and lets air into the right pleural cavity stops airflow into the right lung because the: a. lung cannot be expanded b. rib cage cannot be expanded c. diaphragm cannot be lowered d. air dries and stiffens the lung - correct answer A. Lung cannot be expanded Why: As air builds up, pressure inside the pleural space increases and causes the lung to collapse. The pressure also prevents the lung from expanding when you try to inhale, causing chest pain and shortness of breath. Which of the following procedures would be the LEAST likely to prevent bacterial synthesis of the superantigen protein? A. Adding tRNA nucleotides that can bind to mRNA and bacterial ribosomes B. Adding a repressor protein that binds to the operator site of the bacterial superantigen gene C. Adding a specific complementary nuclei acid sequence than can bind mRNA transcribed from superantigen gene D. Adding a stop codon within the bacterial superantigen gene - correct answer A. Adding tRNA nucleotides All the multiple choice answers would be effective ways to prevent synthesis of the super antigen but adding tRNA nucleotides would be unlikely to prevent synthesis of antigen. Adding tRNAs will just give more resources for translation to proceed. Adding tRNAs absolutely promote translation and would not prevent the 'super antigen' from being produced. tRNAs will only bind to their corresponding codons (give or take with the "wobble-base pair"), so you're essentially speeding up the translation process by bringing amino acids to the mRNA and ribosome. Rate of endocytosis vary from cell type to cell type. What cell would be predicted to have the highest rate of endocytosis a. Macrophage b. Erythrocyte c. Osteoblast d. Neuron - correct answer A. Macrophage Endocytosis is a process by which cell takes material from outside the cell by engulfing it into the cell and form vesicles. Macrophages are the MVP of engulfing Translation of antiboddy proteins in eukaryotic cells is associated with what organelle? a. nucleus b. mitochondrion c. Endoplasmic reticulum d. Golgi apparatus - correct answer C. Endoplamic Reticulum Where translation of protein happens, synthesis is accomplished by ribosomes Antidiurectic hormone (ADH) acts to decrease urine output by increasing water permeability of the walls of a. the glomerulus b. bownman's capsule c. the loop of henle d. the distal tubule and collecting duct - correct answer D. The distal tubule and collecting duct ADH acts on the distal tubule and collecting duct to increase water permeability by the insertion of aquaporins in the plasma membrane Suppose that an extract from a muscle cell contains only the following: all enzymes of the glycotic pathway, including the enzyme that converts pyruvate to lactate, phosphate and other salts, NAD+ and ADP. When the extract is incubated anaerobically and glucose in introduced, neither pyruvate nor lactate is produced. What must be added in order fro pyruvate to be made? a. O2 b. ATP c. NADH d. Acetyl-coenzyme A - correct answer B. ATP ATP must be added, in order to gain ATP, you need to sacrifice ATP. Which of the following hormones is LEAST likely regulated by the anterior pituitary? a. cortisone b. epinephrine c. progesterone d. thyroxin - correct answer B. Epinephrine Epinephrine is secretes by the adrenal medulla and it's secretion is controlled by the autonomic nervous system. The mineral component of human bone is a salt that consists primarily of all the following EXCEPT: a. calcium b. phosphate c. potassium d. hydroxyl groups - correct answer C. Potassium The inorganic(mineral) component of a bone consist of calcium phosphate similar to hydroxyapatite- so it would be expected to contain calcium, phosphate and hydroxyl groups. A researcher has a short polynucleotide strand with the following base sequence: AUCCCUGG. This strand must be: a. template DNA