Biology 235- Exam 1 Questions and Answers | Latest Updated 2026 | Guaranteed Pass

Biology 235- Exam 1 Questions and Answers | Latest Updated 2026 | Guaranteed Pass •circulatory- transport materials between cells of body •digestive- breaks down food to be transported into body •endocrine- coordination of body function •immune- defend against foreign invaders •integumentary- protect against external environment •musculoskeletal- support and movement of body •nervous- coordinate body function using electrical signal •reproductive- to reproduce •respiratory- bringing air in and out of the body •urinary- waste removal; maintain water - answer-List the 10 organ (body) systems and describe one function for each of them. Table 1-1 Anatomy is the study of structure while physiology is the study of what? - answer-Physiology is the study of function and how the body part does what it does Explain your understanding of homeostasis. Note the difference between the intracellular fluid (ICF) and extracellular fluid (ECF). In addition to blood plasma, what constitutes the ECF? - answer-Homeostasis is the body's tendency to maintain a certain internal environment. The body's internal environment is extracellular fluid which contains blood plasma and interstitial fluid. extracellular fluid is everything inside the body but outside the cell. Intracellular fluid is fluid within the cells List 5 factors/homeostatic balances in the body need to be maintained within certain limits. Why must these factors be maintained? - answer-oxygen lvls, glucose lvls, temperature, pH, salt and water. these factors must be maintained because our body can only function in a certain range.For each of the five factors you listed, mention one body systems involved with their homeostasis. - answer-oxygen lvl- respiratory, glucose lvls- digestive, temperaturecirculatory, pH- respiratory, salt and water- urinary Draw an animal cell including the following structures: cell membrane, nucleus, endoplasmic reticulum, Golgi apparatus, mitochondria and lysosomes. - answer-DRAW ON PAPER! In what part of the cell are chromosomes located? - answer-the nucleus What is the function of ribosomes? Rough endoplasmic reticulum and Golgi apparatus? - answer-•ribosomes is where proteins are made •rough ER is stubbed with ribosomes and responsible for assembly of proteins •golgi apparatus- modify, transport, sorting molecules Briefly, what is the mitochondria? Lysosomes? - answer-•mitochondria- where ATP is made •lysosome- responsible for waste Explain the difference between desmosomes and tight junctions. Fig. 3.8 - answerDESMOSOMES anchor cells to each other and TIGHT JUNCTION anchor cells and prevent fluid and molecules from moving between cells What type of molecules can pass freely through the lipid-bilayer part of the cell membrane? What properties determine if a molecule will pass through? Fig. 5.7 - answer-hydrophobic molecules can pass freely. concentration gradient determines if the molecule will pass freely Explain what a concentration gradient is. Can molecules flow up their concentration gradient? Explain. - answer-Concentration gradient is the difference in concentration of a substance in two places. One side is high and the other is low in concentration. Molecules can flow up their concentration gradient. Flowing against it requires active transport because energy is needed for the substance that is low in one place to move on to the higher concentration side.Besides structural, list 3 other functions of membrane proteins. Fig. 5.8 - answer-can be catalyst, receptors, and transporters Explain the difference between facilitative diffusion and simple diffusion. - answerfacilitative diffusion requires protein transporter while simple diffusion doesn't Explain the difference between active and passive transport. - answer-active transport requires energy while passive transport requires no energy Explain the difference between protein channels and protein carriers. Fig. 5.10 - answerProtein channels are gated and chooses which molecules to let through. Protein carriers are like revolving doors. The door only opens to one side at a time. What if the difference between a uniport, symport and antiport? - answer-•uniport moves one molecule •symport moves two molecules in the same direction •antiport moves two molecules at a time in the opposite direction Explain the mechanism of the Na-K+ ATPase (Fig. 5.15) and note at which step ATP is used. - answer-Na+ binds to the site. ATP comes in and phosphorylates with protein this causes the transporter to switch to the other side. Na+ is then released. K+ binds to the site causing causing the phosphate to be released. when phosphate is released the transporter flips back to the other side and K+ released from the site again. The process continues. ATP is used in the second step where the protein gets phosphorylated Explain how glucose gets transported from one side of the cell to another. Fig. 5.21 Make sure to explain the roles of each of the three membrane proteins. - answer-Glucose and sodium enter the cell through a symport. Glucose comes in from low to high-active and facilitated and goes into the extracellular fluid. Sodium is present so that the energy from sodium coming in allows glucose can come in. Sodium comes in from high to low-passive and facilitated and goes out of the cell. ATP is needed to keep the sodium concentration low. Explain the concepts of inhibition and saturation as they apply to transport proteins. - answer-when a carrier reaches its saturation rate, it has reached it's maximum rate and rate will not continue to increase. inhibition means the protein carrier is inhibited at the momentExplain the process of transcytosis. Fig. 5.22 - answer-transcytosis is when a large molecule undergoes exocytosis in one end and exocytosis happens in the other end of the cell. Compare and contrast synaptic vs. endocrine signaling in terms of specificity of signal. Fig. 6.1 - answer-•endocrine signaling is a form of long distance communication where hormone is released into the blood. if the cell has a receptor it will respond and if it does not then there will be no response. •synaptic signaling is also a form of long distance communication where neurotransmitters are released by neurons to activate other neurons. What types of signals (hydrophobic or hydrophilic) can only stimulate cell-surface receptors? Is the cellular response to hydrophobic signals faster or slower than hydrophilic ones? - answer-hydrophilic have receptors on the cell's surface. hydrophobic signals are slower because it leads to the production of new proteins. Explain the action of a G-protein coupled receptor making sure to clearly state to function of adenylate cyclase, cAMP and protein kinase A. Fig. 6.8 - answer-A G-protein coupled receptor actives the g protein causing it to activates adenylate cyclase. The activation of adenylyl cyclase converts ATP into cAMP. cAMP actives protein kinase A which phosphorylates other proteins. The phosphorylated protein triggers a cellular response. What is meant by signal transduction? What is meant by a 2nd messenger? - answerTransduction means moving a signal across the membrane. 2nd messenger means intracellular message that is translated from one signal into a response What is meant by amplification? - answer-Amplification means to make something larger What molecular group do protein kinases help transfer to proteins? What effect does this have on the protein? - answer-Protein kinases help transfer a phosphate group from ATP to a protein. The phosphorylated protein leads to a cellular response. Explain the difference between an agonist and an antagonist - answer-An AGONIST binds to a receptor and causes the same response while an ANTAGONIST binds to a receptor and causes no response.Explain a possible benefit of having different receptors for the same ligand (signaling molecule). Fig. 6.13 - answer-Having different receptors for the same ligand triggers different responses. the responses happen at the same time. Explain the difference between tonic and antagonistic control of homeostatic balance. Fig. 6.15 - answer-Tonic control of homeostatic balance involves controlling one signal and antagonistic control involves controlling two or more signals Explain the concept of negative feedback. Indicate what is meant by a sensor, an integrating center and an effector. Fig. 6.16. Use blood pressure (Fig. 15.14) as an example - answerNegative feedback- a homeostasis loop so that the body can maintain a near set point. When your body has high blood pressure, a sensor from the carotid and aortic baroreceptor is sent to the integrating center which is the control center for the brain. The brain compares the signal to the body's set point to determine if the blood pressure is too high or low. If it is high, this activates the parasympathetic neurons and decreases sympathetic. if blood pressure is low, this activates the sympathetic neurons and decreases parasympathetic. By doing so, this sends a signal to the SA node and ventricles telling them to constrict or dilate the arterioles and veins. What is meant by a set point? Are set points constant? - answer-Set point is the point where the body is able to function optimally. Set points are constant(?) List the basic structures of a neuron and give the function of each part. Fig. 8.2 - answerDendrites- an extension of the cell body; receives the input signal, axon- sends the output signal, myelin sheath- prevents the signal from slowing down; cell body- receives input and determines output **What types of stimuli causes ion channels to open? When they open, in will ions flow in or out of the cell? - answer-Some types of stimuli that causes ion channels to open are neurotransmitters or 2nd messenger. Another stimuli would be a voltage ion channel which responds to electricity. The concentration gradient determines if the ion flows in or out of the cell. Define the terms depolarization, repolarization and hyperpolarization. Fig. 8.7 - answerDepolarization- when the potential goes up. Repolarization- when the potential goes back to resting. Hyperpolarization- when the potential goes below restWhat is meant by the threshold, subthreshold and suprathreshold? - answer-•Threshold is the minimum point for an action potential to occur. •Subthreshold is the point that is not strong enough for an action potential to occur. •Suprathreshold is the point that is strong enough for an action potential to occur. Explain the difference/relationship between a graded potential and an action potential. - answer-Graded potential is when there is small changes in voltage and there needs to be a certain threshold met in order for the signal to be sent. An action potential is when there are large changes and the potential can move down the axon. What channels are opening (Na+ or K+) during the rising phase and in which direction (in or out) are ions flowing? What channels are opening (Na+ or K+) during the falling phase and in which direction (in or out) are ions flowing? Fig. 8.9 - answer-During the rising phase Na+ channels are opening and Na+ is going in. During the falling phase, K+ channels are opening and K+ is going out. Explain what is meant by a refractory period. Fig. 8.10/8.12 - answer-A refractory period is a period of time in which an action potential is unable to fire again. Must wait to fire another action potential.