Ace BSCI Exam 1: 50+ Verified Practice Questions with Answers | 2025 Exam Updates.

Ace BSCI Exam 1: 50+ Verified Practice Questions with Answers | 2025 Exam Updates. Includes verified questions and detailed answer explanations covering all major Exam 1 topics — perfect for students in BSCI 201 or BSCI 202, covering cells, tissues, integumentary system, skeletal, cardiovascular, and more depending on your course. -Below are several structures associated with typical cells. On the line next to each one write A if it is normally associated with animals, B if it is normally associated with plants, and C if it is normally associated with prokaryotes. Central Vacuole Cell wall Nucleus - -_____B_____Central Vacuole __B_C__Cell wall ____A__B____Nucleus -Concisely describe a beta sheet by stating which level of protein structure is it and clearly explaining the bonds that form it and keep it together, including the type of bonds and what specific atoms the bonds are between. - -Secondary, Hydrogen bonding between H's in the amine groups and the O's of the carbonyls groups in the backbone. R groups do not play a role. Another way to describe the beta sheet is that it is a stretch of polypeptide chain typically 3 to 10 amino acids long with the backbone in an extended conformation. "Unlike the alpha helix, the beta sheet is formed by hydrogen bonds between protein strands, rather than within a strand." -Could this reaction be driven in the cell by coupling it to ATP hydrolysis Why or why not? XA+Y→XY ΔG = +10 kcal/mol couple with ATP ΔG = -7.3 kcal/mol - -No the reaction will not be driven because delta G will be positive. For a reaction to be driven and spontaneous it needs to be a -G 10 - 7.3 = +2.7 -Explain the Lock-and-key model and the Induced fit model of enzyme-substrate interaction. Which is currently considered to be the most accurate model and why? - -Induced fit is the most accurate model Lock and key-- Substrate fits perfectly into the active site of an enzyme. No change in the active site Induced FIt-- Substrate and active site are not a perfect fit but are still complementary -The K+ channel is an example of a transmembrane protein (a protein that spans the phospholipid bilayer of the plasma membrane). What type of amino acids are likely to be found A) lining the pore and central cavity through which K+ passes? B) in contact with the hydrophobic core of the phospholipid bilayer containing fatty acyl groups? C) in the cytoplasmic domain of the protein? - -A) lining the pore and central cavity through which K+ passes? Polar and charged B) in contact with the hydrophobic core of the phospholipid bilayer containing fatty acyl groups? Non polar and hydrophobic C) in the cytoplasmic domain of the protein? Polar and hydrophilic A reaction that is not spontaneous - -has a +ΔG An exergonic process ________. - -has a -ΔG, is spontaneous, and does not necessarily proceed very quickly Below are structures associated with typical cells. On the line next to each one write A if it is normally associated with animals, B if it is normally associated with plants, and C if it is normally associated with prokaryotes Cell Wall Plasma Membrane - -___B, C__Cell wall __A, B, C__Plasma membrane Besides the type of bond formed, what is the major difference between starch and cellulose? - Cellulose: is mostly for structure of the cell wall in plants. The bonds they use are beta bonds which make the molecules less flexible. Starch: Serves for storage of energy in plants. Branched structure bonded by alpha 1-6 bonds. Briefly explain one of the three mechanisms described in class by which enzymes decrease the activation energy of a reaction (accelerate the reaction rates). - -Orientation: getting the substrates aligned properly to make forming bonds correctly easier Reactivity: giving the substrate a charge by sharing electrons to more easily break bonds Inducing stress: distorting the substrate to break bonds more easily Compare and contrast prokaryotes and eukaryotes. List 1 thing they have in common, and 1 way in which they are different - -Both have ribosomes and DNA and RNA Both cells acquire and utilize energy Eukaryotes have membrane bound organelles Prokaryotes have no nucleus and have only ribosomes