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BIOD 331 exam 1 Newest 2025 Complete Questions And Correct Answers (Verified Answers) |Already Graded A+
What are G-linked protein receptors? - ANSWER-On-off switch. have a ligand-binding extracellular receptor. They convert external signals into internal signals. When the receptor is on it bind to GTP, when it's off, it binds to GDP.
What are enzyme-linked receptors? - ANSWER-Growth factors.Have their ligand-binding site on the outside of the cell membrane. It activates an intracellular domain with enzyme activity, linked to growth factors, and respond to increased potassium-sodium exchanges, influxes of calcium, and stimulation of glucose and amino acid uptake.
What are Ion-channel-linked receptors? - ANSWER- Neurotransmitters. Found on nerve and muscle cells. They are highly excitable and synaptic signaling is rapid.Neurotransmitters use this type of signaling to open or close ion channels formed by integral proteins in the cell membrane.
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What is diffusion? - ANSWER-Molecules go from an area of high concentration to an area of low concentration until they are equally distributed. i.e. Electrolytes move from an area of high concentration one one side of a cell membrane to an area of lower concentration on the other side.
What is facilitated diffusion? - ANSWER-uses a transport protein to help lipid insoluble or large molecules pass through the cell membrane.
What is active transport? - ANSWER-Cells use energy to move
against an electrical or chemical gradient. Example: sodium-
potassium-ATPase pump. This pump moves sodium from inside the cell to the extracellular region and returns potassium to the inside of a cell.
What is the most important active transport system and why is it important? - ANSWER-The sodium-potassium-ATPase pump is the most important active transport system. The removal of sodium and the replacement with potassium causes the cell to maintain its structural integrity. If sodium remained in the cell, the cell would swell and die.
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Define endocytosis. - ANSWER-Endocytosis is the process by which a cell takes in substances from outside itself by engulfing them in a vesicle (such as nutrients or pathogens that immune cells engulf and destroy).
What is pinocytosis? - ANSWER-Pinocytosis is "cell drinking", where the cell engulfs small solid or fluid particles such as proteins and electrolytes.
What is phagocytosis? - ANSWER-Phagocytosis means "cell eating" where the membrane engulfs then kills microorganisms or other molecules. Once the particle is enclosed, a phagosome is formed and it moved into the cytoplasm where a lysosome
meets it to be destroyed. (think: white blood cells, leukocytes)
Why are ion channels necessary? - ANSWER-Ions are unable to cross the cell membrane due to the arrangement of hydrophilic heads and hydrophobic tails in the lipid bilayer. In order to cross the membrane, they must interact with membrane receptors.
What is primary active transport? - ANSWER-ATP is used directly to transport the substance
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