BIO TEST QUESTIONS

A. Swelling of the region Capillaries are the smallest diameter vessels. They branch off of arterioles on one side and connect to venules on the other side, i.e. they convey blood between arteries and veins. Hydrostatic pressure pushes plasma out of capillaries at the arterial end, whereas osmotic pressure pulls wastes back into capillaries at the venous end. A blockage in the capillary would disrupt this exchange of substances, as well as the blood flow between the adjoining artery and vein. This would result in increased capillary pressure. With an increase in capillary hydrostatic pressure there is going to be more solvent filtering out of the capillary, which will lead to swelling of the region (also known as edema). [Choices B and D]: Hydrostatic pressure pushes fluid out of capillaries at the arterial end. A blockage in the capillary would increase hydrostatic pressure, and therefore increase pressure on the arterial end. This would increase filtration of fluid out of the capillary here. [Choice C]: Osmotic pressure pulls fluid into capillaries at the venous end. A blockage in the capillary would increase osmotic pressure, and therefore decrease interstitial fluid in the venous end. (Interstitial fluid refers to liquid that surrounds tissues and is outside the capillary. Therefore, if osmotic pressure increases on the venous end, more interstitial fluid would enter the capillary. Thereby decreasing the amount of interstitial fluid at the venous end.) Key Takeaways: * Hydrostatic pressure pushes fluid out of capillaries at the arterial end * Osmotic pressure pulls fluid back into capillaries at the venous end (circulatory system)

A buildup of plaque causes a capillary to become blocked off. What would be the expected local effect of this? A. Swelling of the region B. Decreased outward filtration on arterial end C. Increased interstitial fluid on venous end D. Decreased pressure on arterial end

C. Ribosome One of the differences between DNA and RNA is that DNA contains thymine, whereas RNA replaces thymine with uracil. If we radioactively labeled uracil, its location would correspond to parts of the cell that have RNA. Ribosomes perform translation, which is the process of converting mRNA into proteins. Ribosomes are made of rRNA and proteins, therefore if uracil were to be radioactively labeled, we would expect to see it in a ribosome. (cells and organelles)

A eukaryotic cell is placed in a plate containing radioactively labeled uracil. Which structure would the radioactively labeled uracil be seen in? A. Plasma membrane B. Golgi apparatus C. Ribosome D. Chromosome E. Smooth endoplasmic reticulum

E. Liver Carbohydrates come in many forms and are composed of carbon. If carbon is radioactively labeled, then the carbohydrates of the pasta will be labeled. After eating a glucose-rich meal, the excess glucose will be converted to glycogen. Glycogen is the main storage polysaccharide found in humans. Glycogen is primarily stored in the liver. Between meals when our body needs energy, the liver breaks down stored glycogen back into glucose. (digestive system)

A person eats pasta containing 14C-labeled carbohydrates. After digestion and absorption, where would radioactivity accumulate? A. Spleen B. Colon C. Pancreas D. Stomach E. Liver

D. Decreasing temperature Abscisic acid is one of the five plant hormones that are important to know for the DAT. It is secreted in response to plant stress. Typically, plants prefer warmer temperatures that fall within an optimal range for growth, so decreasing temperature is a plausible cause of plant stress. Answer choice [D] is correct. Production of fruit can be associated with plant growth because they contain seeds, which are important in the life cycle of the plant. Gibberellins, an important plant hormone for plant growth, helps promote the production of fruit. We can eliminate answer choice [A]. An increase in sunlight will typically stimulate better growth for the plant because plants require sunlight for photosynthesis. Abscisic acid is produced during plant stress, so we can rule out answer choice [B]. A large amount of rain will simply provide plants with extra water, which will be used in photosynthesis. Rain does not stimulate the production of abscisic acid. We can eliminate answer choice [C]. Pollination season cannot be a trigger for plant stress because it will promote the production of seeds. We can rule out answer choice [E]. (plants)

A plant begins producing a high amount of abscisic acid. What might be the cause of this change? A. Production of fruit B. Increase in sunlight C. Large amount of rain D. Decreasing temperature E. Pollination season

B. Stains pink Gram-negative bacteria contain lipopolysaccharide (LPS), so we must be evaluating a gram-negative bacteria. Gram-negative bacteria stain pink when Gram stained. A. Teichoic acids C. Thick peptidoglycan layer D. Does not secrete endotoxins These are all qualities of Gram-positive bacteria. E. Does not possess a capsule Both Gram-positive and Gram-negative bacteria are covered by a capsule, a virulence factor protecting the bacteria from drying out. (diversity of life)

A researcher is studying bacteria containing lipopolysaccharides. What else would the researcher find in this bacteria? A. Teichoic acids B. Stains pink C. Thick peptidoglycan layer D. Does not secrete endotoxins E. Does not possess a capsule

B. Lysosomes The experiment and graph describe a situation where proteins are being broken down into amino acids over time. Lysosomes are vesicles that contain digestive enzymes that function in the breakdown of nutrients (like proteins) bacteria, and cell debris, as well playing a key role in apoptosis. When mixed with amino acids & proteins, lysosomes would break down what they can digest. * Amino acids are already in a monomeric form and won't be broken down further. * However, proteins will be broken down into their constituent amino acids. Let's look at the graph we've been provided. Over time, the protein amount is decreasing and amino acids are increasing. It makes sense that this would occur if the small particles are lysosomes. These lysosomes are breaking down the proteins (proteins decreasing) into amino acids (amino acids increasing). (molecular genetics)

A researcher isolates small particles from a functioning cell and places them into a mixture of radioactive amino acids and proteins. The amount of amino acids and proteins are then recorded and graphed below. What particles were extracted from the cell? A. Lipid vacuoles B. Lysosomes C. Mitochondria D. Ribosomes E. Histones

B. Ovulation The female hormonal cycle begins in the hypothalamus, which monitors the amount of estrogen and progesterone in the blood. If there is a low amount of these hormones, the hypothalamus will secrete gonadotropin-releasing hormone (GnRH), which stimulates the anterior pituitary to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH will stimulate the development of the follicle and oocyte, and the follicle will secrete estrogen. Positive feedback from estrogen will cause a surge of LH, which will cause ovulation. FSH stimulates follicles in the ovaries to develop and produce estrogen and progesterone. LH stimulates ovulation of the egg and corpus luteum formation. Ovulation causes the completion of meiosis I, which is then arrested in metaphase II. Fertilization causes the egg to complete meiosis II. (reproduction and developmental biology)

A surge in luteinizing hormone causes which of the following? A. Completion of Meiosis II B. Ovulation C. Maturation of follicles D. Thickening of the endometrium

D. Nucleus of a somatic cell To clone an organism, we need to use a somatic cell because its nucleus contains the full genome of the organism. As a result, choice [D] is the correct answer. Choice [A] is incorrect. Gametic cells are haploid and only contain half of the genome of a somatic cell. Choices [B] and [C] are incorrect because the cytoplasm does not contain any genetic material, which is required for genetic cloning; the somatic nucleus contains the complete genome and all the components necessary for genome replication. Choice [E] is incorrect because an ovum is an example of a gametic cell, which are haploid and only contain half of the genome of a somatic cell. (microscopy and lab techniques)

A team of scientists attempt to reproductively clone organism F. Which of the following components from organism F is necessary for successful cloning? A. Gametic cell B. Cytoplasm of a somatic cell C. Cytoplasm of a germ cell D. Nucleus of a somatic cell E. Genomic library of an ovum

C. Human chorionic gonadotropin Menstruation is prevented if fertilization occurs. If an embryo implants into the endometrium, the outer layer of the placenta begins to secrete human chorionic gonadotropin (hCG). It maintains the corpus luteum, preventing the corpus luteum from degenerating. The corpus luteum is therefore able to continue to produce progesterone (which continues estrogen production) and this maintains the thickened endometrium, preventing menstruation. (Endocrine System)

After the blastocyst has successfully implanted into the endometrium, what hormone prevents the corpus luteum from degenerating? A. Luteinizing hormone B. Follicle-stimulating hormone C. Human chorionic gonadotropin D. Estrogen E. Progesterone

D. Glucose We are looking for the exception, so keep in mind we need to choose the wrong statement. Photophosphorylation is the process by which light energy is converted into ATP as an energy source. Light energy is captured by photosystems in the electron transport chain and used to excite electrons for the pumping of H+ ions across the thylakoid membrane. The H+ gradient is then used to produce ATP by running H+ ions through an enzyme called ATP synthase. In photosynthesis, the light-dependent reactions rely on photophosphorylation to produce the energy necessary to run the light-independent reactions (Calvin cycle), which then produce glucose through carbon fixation. Thus, glucose is the exception here because it is not a direct product of photophosphorylation; it is produced in the next step after photophosphorylation. Answer choice [D] is correct. ATP is the main energy source that photophosphorylation produces for later use in the Calvin cycle. It is created by ATP synthase, which uses energy from the H+ gradient generated by the electron transport chain. We can eliminate answer choice [A]. Oxygen is a byproduct of photophosphorylation that is produced when water is split into H+ ions, electrons, and oxygen. Answer choice [B] can be ruled out. NADPH is an electron carrier that accepts electrons at the end of the electron transport chain and is therefore considered a product of photophosphorylation. We can rule out answer choice [C]. Hydrogen (H+) ions are produced by the splitting of water molecules as a part of photophosphorylation; these are directly used to produce ATP through ATP synthase. We can rule out answer choice [E]. (photosynthesis)

All of the following are directly produced by photophosphorylation EXCEPT one. Which one is the EXCEPTION? A. ATP B. Oxygen C. NADPH D. Glucose E. Hydrogen ions

B. Present antigens to B and T cells After activation, B cells can differentiate into plasma cells or memory B cells. Plasma cells release antibodies, which circulate in the blood and lymph. After antibodies are released into the humor, they can: Tag corresponding antigens for removal, i.e. signal that it should be phagocytosed Coat antigens with antibodies to neutralize them Activate the complement system These functions share the common goal of annihilating the pathogen containing the specific antigen. Eliminate choices [A], [C], and [D]. In addition, immunoglobulin E (IgE) is a class of antibodies found on basophils and mast cells. Whenever there is an allergen, IgE will bind and trigger the release of histamine from these two cells. Eliminate choice [E]. In contrast, macrophages, dendritic cells, and B cells function as antigen-presenting cells (APCs). APCs act as a bridge between the innate and adaptive immune responses. After they phagocytose the pathogen and break off the antigen, APCs will load the antigen onto the major histocompatibility complex (MHC) molecule and present it to immune cells, ex. B cells and T cells. This is not a function of antibodies; therefore, choice [B] is the exception. (human immune system)

All of the following are functions of antibodies EXCEPT for one. Which one is the EXCEPTION? A. Tag corresponding antigens for removal B. Present antigens to B and T cells C. Coat antigens to neutralize them D. Activate the complement system E. Trigger histamine release

E. Donating reactant groups Enzymes lower activation energy to speed up reactions. Activation energy is the amount of energy required by a chemical reaction to progress. Enzymes reduce the energy of the transition state between reactants and products, which lowers the activation energy. Enzymes work by changing the energy of the transition state to increase the reaction rate, not by contributing reactant groups to the reaction. Enzymes are not consumed by the reactions they catalyze. Therefore the statement in [E] is the exception, and this is our answer. A. Conformational changes that bring reactive groups closer C. Induced fit of the enzyme-substrate complex Enzymes catalyze reactions by binding to reactant molecules, known as substrates. The substrates bind to an enzyme's active site, which is specific for a particular substrate. When substrate binding occurs, slight conformational changes occur in the enzyme-substrate complex for a tighter fit of the substrate in the active site. This adjustment is called the induced fit theory. B. The presence of acidic or basic groups D. Electrostatic attractions between the enzyme and substrate Since enzymes are protein catalysts, amino acids give the active site unique properties and substrate specificity. The degree of active site specificity varies from enzyme to enzyme. These amino acid residues can be weakly acidic or basic, which create a specific environment within the active site for reactions. The presence of acidic or basic groups can donate/accept protons to stabilize charges in the transition state. Stabilization of the activated complex can also be due to the formation of bonds by residues in the active site. The electrostatic attractions between enzyme and substrate lower the activation energy and thus increase the reaction rate. (molecules and fundamentals of biology)

All of the following are mechanisms for enzymes catalyzing reactions EXCEPT one. Which is the EXCEPTION? A. Conformational changes that bring reactive groups closer B. The presence of acidic or basic groups C. Induced fit of the enzyme-substrate complex D. Electrostatic attractions between the enzyme and substrate E. Donating reactant groups

C. H2O Keep in mind that this is an exception question; we are looking for the molecule that is not a product. The Krebs cycle is the part of cellular respiration that takes in acetyl-CoA molecules and stores their energy into electron carriers NADH and FADH2. Recall that each turn of the Krebs cycle uses up 1 acetyl-CoA and produces 3 NADH, 1 FADH2, 1 GTP, and 2 CO2. H2O is the EXCEPTION as it is not a product of Krebs cycle, so we can see that answer choice [C] is correct. CO2 is a byproduct of the Krebs cycle and is exhaled by animals as a result of cellular respiration. We can eliminate answer choice [A]. GTP is produced during the Krebs cycle and is considered equivalent to 1 ATP in energy. Answer choice [B] can be ruled out. FADH2 and NADH are the main electron carriers generated by the Krebs cycle for later use in the electron transport chain, which produces ATP through oxidative phosphorylation. Finally, answer choices [D] and [E] can be eliminated. Key Takeaways: * FADH2 and NADH are the main electron carriers generated by the Krebs cycle. (cellular energy)

All of the following are products of the Krebs cycle EXCEPT one. Which is the EXCEPTION? A. CO2 B. GTP C. H2O D. FADH2 E. NADH

B: Drains into the digestive system This is a false statement and therefore the answer choice is correct. Certain lymphatic capillaries (lacteals) absorb dietary fats in the villi of the small intestine. These lacteals transport fat from the digestive system to rest of the body, not towards the digestive system. A. Contains one way valves This is a true statement and therefore the answer choice is incorrect. Because the lymphatic system is a low pressure system, valves are required to make sure lymph only travels in the forwards direction. C. Lymph is propelled by contraction of smooth muscle as well as skeletal muscle This is a true statement and therefore the answer choice is incorrect. The lymphatic system relies on both smooth muscles in the vessels and contraction of the vessels by adjacent skeletal muscle in order to be propelled. D. Produces B and T cells This is a true statement and therefore the answer choice is incorrect. The lymphatic system consists of the bone marrow, the spleen, and the thymus. It also consists of lymph nodes, which are scattered throughout the body. The main white blood cell type in the lymphatic system are the lymphocytes (lymphocytes are T cells and B cells). Lymphocytes originate from the bone marrow, with T cells maturing in the thymus and B cells maturing in the bone marrow. E. Returns fluids that escaped from blood vessels This is a true statement and therefore the answer choice is incorrect. The lymphatic system captures interstitial fluids and returns it to the blood system. (circulatory system)

All of the following are true of the lymphatic system EXCEPT one. Which is the EXCEPTION? A. Contain one way valves B. Drains into the digestive system C. Propelled by contraction of smooth muscle as well as skeletal muscle D. Produces B and T cells E. Returns fluids that escaped from blood vessels

B. Gamete isolation In the case of sympatric speciation, speciation occurs without the presence of a geographical barrier. In allopatric speciation, speciation occurs due to the presence of a geographical barrier. Gamete isolation is when gametes cannot recognize and fertilize each other. This type of isolation prevents two species from interbreeding after they've already been separated and formed different species. It is not a mechanism that causes speciation to occur. (evolution)

All of the following are ways to achieve sympatric speciation EXCEPT one. Which is the EXCEPTION? A. Balanced polymorphism B. Gamete isolation C. Polyploidy D. Hybridization

E. Oxytocin Since the hypothalamus, anterior pituitary and posterior pituitary all secrete/release different hormones, it is easy to mix up the hormone and its respective origin on the DAT. It is important to know this summary table: Hypothalamus: GnRH, TRH, CRH, GRH, Oxytocin, ADH (vasopressin) Anterior Pituitary: FSH, LH, TSH, ACTH, Prolactin, GH Posterior Pituitary: stores and releases oxytocin and ADH. They are made by the hypothalamus. As we can see, oxytocin is not secreted by the anterior pituitary gland. It is produced by the hypothalamus and released by the posterior pituitary. Choice [E] is the correct answer. *Tip: All of the hormones with the name "releasing" are secreted by the hypothalamus e.g. GnRH (gonadotropin releasing hormone). All of the hormones with the name "stimulating" are secreted by the anterior pituitary e.g. FSH (follicle stimulating hormone). (endocrine system)

All of the following endocrine hormones are secreted by the anterior pituitary gland EXCEPT one. Which one is the EXCEPTION? A. Follicle stimulating hormone B. Thyroid stimulating hormone C. Prolactin D. Adrenocorticotropic hormone E. Oxytocin

C. Mitochondria is the only structure that is not part of the endomembrane system. Mitochondria are organelles in eukaryotic cells that produce ATP. The endomembrane system is a group of organelles and membranes that work together to modify, package, and transport proteins and lipids that are entering or exiting a eukaryotic cell. (Cells and Organelles)

All of the following structures are a part of the endomembrane system EXCEPT one. Which is the EXCEPTION? A. Endoplasmic reticulum B. Central vacuoles C. Mitochondria D. Gogi apparatus E. Plasma membrane

C. Fibrin The ultimate cause of a blood clot is the action of fibrin; if fibrin is mixed with a blood sample, it would be expected to see a high level of blood clotting. A. Hemoglobin Hemoglobin is a protein in red blood cells that reversibly binds to oxygen. Hemoglobin primarily functions to carry oxygen around our bodies, not to form blood clots. B. IgE IgE is a type of antibody that is responsible for allergic reactions. They are found on basophils and mast cells as antigen receptors and trigger the release of histamine whenever an allergen is bound. Histamine goes on to cause an allergic reaction. D. Sodium Although sodium has many functions in the human body, it is not involved in the process of blood clot formation. E. Complement proteins Complement proteins are an innate immune response to pathogens. Complement proteins activate each other in a protease cascade, resulting in pathogen opsonization, the formation of membrane attack complexes, and the amplification of the inflammatory response. Complement proteins do not result in blood clotting. (circulatory system)

An experiment was conducted to compare the effect of three unidentified compounds on the blood clotting of a hemophiliac patient. Based on the results below, what is most likely to be compound 2? Compound Clotting 1 None 2 High 3 None A. Hemoglobin B. IgE C. Fibrin D. Sodium E. Complement proteins

D. Interrupted zona hatching A blastocyst develops in one of the stages of embryogenesis; it contains a trophoblast (outer ring of cells) and an inner cell mass. The blastocyst also has a hollow cavity called a blastocoel. The trophoblast is required for implantation of the embryo in the uterus and must replace the zona pellucida through a process called zona hatching in order for implantation to occur. If zona hatching is interrupted, then the blastocyst will fail to implant. Thus, answer choice [D] is correct. Capacitation is the final maturation step for sperm. It occurs in response to interaction with secretions from the uterine wall as the sperm are traveling up the female reproductive tract. Since this is a process that sperm undergo, we can eliminate answer choice [A]. Cleavage is the initial step after fertilization through which the zygote rapidly divides without changing its total mass. The question mentions that the oocyte developed into a blastocyst, so we can assume that cleavage has already occurred successfully. Thus, we can rule out answer choice [B]. Polyspermy fertilization happens when more than one sperm fertilizes the egg and usually results in the death of the zygote. We can eliminate answer choice [C]. The hypoblast is one of the two layers that comes from the inner cell mass; part of it naturally undergoes apoptosis. Since this does not affect implantation, we can eliminate answer choice [E]. (reproduction and developmental biology)

An oocyte develops into a blastocyst but fails to implant. Which of the following is the most likely cause? A. Disrupted capacitation B. Unsuccessful cleavage C. Polyspermy fertilization D. Interrupted zona hatching E. Apoptosis of the hypoblast

B. Prokaryotes lack the ability to remove introns One of the main differences between how eukaryotes and prokaryotes manage their gene expression has to do with post-transcriptional modifications. Eukaryotes make a number of alterations to newly transcribed RNA, whereas prokaryotes tend to directly translate RNA almost right after it's been produced. One of the post-transcriptional modifications that eukaryotes perform is RNA splicing. Eukaryotic genes are composed of introns and exons. Prior to translation, a spliceosome will remove all of the introns such that the functional gene is made up of the right combination of exons. If a prokaryotic cell were to have human (eukaryotic) DNA directly inserted into its genome, this DNA would still contain its full array of introns and exons. The prokaryotic cell does not have a mechanism for splicing out introns, and therefore the human gene would not be correctly expressed. It is still technically possible to produce eukaryotic gene products within prokaryotic cells via the use of reverse transcriptase. This enzyme can be used to convert mRNA that already has its introns removed back into cDNA (complementary DNA). This cDNA can be used by prokaryotes to successfully express a eukaryotic gene. (Molecular Genetics)

An unedited human gene is inserted into a prokaryote to study its function. However, the prokaryote does not express the inserted gene. Which of the following is the most likely reason the prokaryote cannot express the human gene? A. Prokaryotes are unable to transcribe eukaryotic DNA B. Prokaryotes lack the ability to remove introns C. Prokaryotic ribosomes cannot translate eukaryotic mRNA D. Eukaryotic DNA contains histones that prevent transcription E. Prokaryotes use a separate genetic code to store information

B. Blastocyst Fertilization usually takes place in the oviduct. As the fertilized egg travels down to the uterus, this is when cleavage happens. When the fertilized egg reaches the uterus, it will usually be at the blastocyst stage. The blastocyst is the one that implants into the uterine wall of the mother. (reproduction and developmental biology)

At which stage does the embryo implant into the uterine wall? A. Morula B. Blastocyst C. Gastrula D. Embryo E. Follicle

D. Stem cells reside in cancellous bone The pelvis is an irregular bone composed of thin cortical layers surrounding abundant cancellous interiors. Cancellous bone is the inner network within bones. In contrast to cortical bone, it does not contain osteons; rather, it contains a web of trabeculae that soak up bone marrow like a sponge. This bone marrow (specifically red bone marrow) is the site of hematopoiesis, the process in which stem cells create new blood cells. Because these stem cells reside in cancellous bone, it makes sense that if abnormal levels of blood cells were detected, the next diagnostic step would be to analyze a sample of bone marrow obtained from the pelvis. Choice [D] is the answer. (skeletal system)

Blood tests that indicate abnormal levels of blood cells are often followed by bone marrow aspiration, during which a portion of bone structure is removed from the pelvis. Why is this biopsy required for diagnosis? A. Sesamoid bones are hematopoietic B. Yellow bone marrow is multipotent C. The pelvic girdle is rich in lymph nodes D. Stem cells reside in cancellous bone E. Leukocytes mature in the bone marrow

C. Assembly The life cycle of a virus is broken down into the following steps: 1. Attachment 2. Penetration 3. Uncoating 4. Synthesis 5. Assembly 6. Release. Bootcamp Mnemonic: Think about someone who has a viral infection sneeze, and her sneeze sounds like "APUSAR!". While the capsid components are manufactured during synthesis, the capsid itself comes together and is formed during the assembly process. (Molecular genetics)

During which stage of viral replication is the capsid formed? A. Attachment B. Synthesis C. Assembly D. Release E. Penetration

C. Glycolysis, pyruvate decarboxylation, citric acid cycle Glycolysis (produces NADH): Glucose → 2 pyruvate + 2 NADH 2 ATP. One glucose molecule enters. An investment needs to be made: the energy of activation for glycolysis is 2 ATP. The cell invests 2 ATP into glycolysis to phosphorylate intermediates, as part of the reaction. Therefore, while glycolysis makes 4 ATP, the process only net produces 2 ATP (as 2 ATP were invested in). Additionally, it produces 2 NADH and 2 pyruvate. Pyruvate decarboxylation (produces NADH): Pyruvate → CO2 + NADH + Acetyl CoA The step of cellular respiration that takes the 3 carbon pyruvate generated during glycolysis and processes that pyruvate to form a 2 carbon acetyl CoA, CO2, and NADH. Krebs cycle (produces NADH): Acetyl CoA → CO2 + NADH + FADH2 + ATP The two acetyl CoAs from pyruvate decarboxylation enter. Each 2C acetyl CoA will join a four carbon oxaloacetate, and form a six carbon citrate (hence the alternative name for the Krebs cycle called citric acid cycle). For every acetyl CoA, Krebs cycle produces 2 CO2, 3 NADH, 1 FADH2, and 1 ATP. So for every two acetyl CoA that enters the Krebs cycle: 4 CO2, 6 NADH, 2 FADH2, and 2 ATP are produced. Electron transport chain (does not produce NADH): NADH + FADH2 + O2 → H2O + ATP NADH and FADH2 are electron carriers. They harness the energy of redox reactions occurring in the earlier steps of cellular respiration (glycolysis, pyruvate decarboxylation, Krebs cycle) and bring these electrons to the electron transport chain. Look at the diagram below. In this example, NADH is oxidized by the first complex, and releases its electrons (this regenerates NAD+). As this happens, hydrogen is pumped from the matrix of the mitochondria into the intermembrane space. A series of additional redox reactions occurs, and as the electrons are transferred, more protons are shuttled. This creates a chemiosmotic gradient. As hydrogen flows back into the matrix down this gradient, it powers an ATP synthase to spin, which generates ATP. This is oxidative phosphorylation. (cellular energy)

During which stages of cellular respiration is NADH produced? A. Glycolysis, electron transport chain B. Citric acid cycle, electron transport chain C. Glycolysis, pyruvate decarboxylation, citric acid cycle D. Glycolysis, pyruvate decarboxylation, citric acid cycle, electron transport chain

D. A clade is present that includes the mouse, rat and their common ancestor A cladogram is a type of phylogenetic tree that shows the inferred evolutionary relationships among various biological species. Every cluster on a phylogenetic tree is called a clade, which includes an ancestor and all of the descendants from that ancestor. A clade could be as big as the entire tree, or just be a small branch at the tip of that tree. Looking at the cladogram in the question, mice, rats, and their common ancestor form a clade. (evolution)

From the given cladogram, what conclusion can be drawn? A. There is a polytomy present between rhesus and humans B. Groups are separated by instances of adaptive radiation C. Humans and chimps are members of the outgroup D. A clade is present that includes the mouse, rat and their common ancestor E. The opossum branch represents the root of this cladogram

E. Simple diffusion Gas exchange in tissues occurs via simple diffusion. Differences in partial pressure allow gases to flow from areas of high partial pressure to areas of low partial pressure through simple diffusion. In erythrocytes in the systemic circulation, the partial pressure of carbon dioxide is low. As a result, carbon dioxide continuously diffuses from the tissues into the red blood cells since the partial pressure of carbon dioxide is high in the tissues and low in the blood. Similarly, when the blood approaches the lungs in the pulmonary circulation, the partial pressure of carbon dioxide is lower in the lungs than in the blood. As a result, carbon dioxide leaves the blood and enters the lungs, where it is expelled during expiration. This allows for an easy and quick method to exchange unwanted for wanted gases. The same pattern of high-to-low simple diffusion occurs for oxygen, allowing oxygen-rich lungs to transport oxygen to oxygen-poor tissues. A. Active transport Active transport occurs when substances travel against their concentration gradient and require the consumption of energy by carrier proteins. An example of active transport is the sodium-potassium pump which establishes the membrane potential in neurons. B. Chemiosmosis Chemiosmosis is the movement of ions traveling down electrochemical gradients. An example of chemiosmosis is the movement of protons from the mitochondrial matrix into the intermembrane space to create an electrochemical gradient to synthesize ATP. C. Bohr effect The Bohr effect describes hemoglobin's decreased oxygen affinity when carbon dioxide is high. The effect contributes to changes in hemoglobin affinity, not gas exchange. D. Haldane effect The Haldane effect describes hemoglobin's increased carbon dioxide affinity when oxygen is low. The effect contributes to changes in hemoglobin affinity, not gas exchange. (respiratory system)

How is carbon dioxide transported from body tissues to blood to the lungs? A. Active transport B. Chemiosmosis C. Bohr effect D. Haldane effect E. Simple diffusion

B. 23 During prophase I of meiosis, homologous chromosomes pair up to form tetrads, allowing for crossing over to take place. If the total number of chromosomes in a cell is 46, and the cell is diploid, then 23 homologous pairs would line up in the form of tetrads. Remember that one tetrad consists of two chromosomes which have undergone synapsis to pair up, allowing for crossing over to occur at regions called chiasmata. (Cell Division)

If 2n = 46, how many tetrads are present during metaphase I? A. 12 B. 23 C. 46 D. 69 E. 92

D. Inhibit the lacl product The lac operon is a type of transcriptional control mechanism found in prokaryotes. The lac operon is an inducible operon, meaning it is usually repressed (by the lac repressor protein, the lacl product). It is only fully turned on when glucose is not available but lactose is. Allolactose is a form of lactose. When allolactose levels are high, allolactose binds directly to the lacl gene product (lac repressor protein) and prevents it from repressing the lac operon. Therefore, choice [D] is the correct answer, and choice [C] is incorrect. Choices [A], [B], and [E] are incorrect because they all describe genes within the lac operon. The lac operon controls 3 genes — lacZ, lacY, and lacA, which produce proteins that help metabolize lactose. Allolactose does not interact with the lac operon itself - it only interacts with the lac repressor protein. (molecular genetics)

In the lac operon, what function does allolactose fulfill? A. Activate the lacZ product B. Inhibit the lacZ product C. Activate the lacl product D. Inhibit the lacl product E. Inhibit the lacA product

D. Female gametophyte First let's figure out sporophytes vs. gametophytes: We should be familiar with the alternation of generations, which summarizes the observation that plants alternate between their haploid and diploid forms. Notably, a sporophyte produces spores via meiosis, and the spores divide via mitosis to become the gametophyte, a haploid structure. We're looking for megaspores, which we know divide via mitosis to become gametophytes. Therefore we can eliminate choices [A] and [C] which deal with sporophytes. Now, let's identify male vs. female: Heterosporous plants produce both a female and male spore, of which the microspore becomes the male gametophyte, and the megaspore becomes the female gametophyte. The names refer to the size of the spore; microspores are smaller than megaspores. Bootcamp Mnemonic: During pregnancy, a woman's belly is much bigger than a man's (usually). Her belly is mega (large) compared to the man's belly (small = micro). So remember: Woman belly = female megaspore Man belly = male microspore Therefore, megaspores develop into female gametophytes. (plants)

Megaspores will develop into which of the following? A. Male sporophyte B. Male gametophyte C. Female sporophyte D. Female gametophyte

B. Reabsorption of calcium ions Parathyroid hormone increases calcium levels in blood. It does this in part by stimulating the kidney to reabsorb more calcium. It also causes the bones to release calcium. The parathyroid glands release parathyroid hormone (PTH), which stimulates the kidney to reabsorb more calcium. PTH also causes the bones to release calcium by indirectly stimulating osteoclasts. Osteoclasts are the bone resorbing (breaking down) cells. If bone is being resorbed, calcium is being liberated, and blood calcium levels increase. Calcitonin is a hormone which lowers calcium levels in the blood (calcitonin 'tones down' calcium). Calcitonin is secreted by the parafollicular cells (C cells) of the thyroid gland. Calcitonin limits calcium reabsorption in the kidney's nephrons and limit calcium absorption in the intestines. Calcitonin also causes bones to take up calcium by stimulating osteoblasts to build more bone (osteoblasts build bone). Building bone consumes calcium phosphate, lowering calcium in the blood. Calcitonin also inhibits osteoclasts. If less bone breakdown is occurring, less calcium is being released from bone. (skeletal system)

Parathyroid hormone will increase which of the following in the nephron? A. Reabsorption of potassium ions B. Reabsorption of calcium ions C. Reabsorption of water D. Secretion of chloride ions E. Secretion of sodium ions

A. respiratory muscles. Peripheral chemoreceptors help maintain cardiorespiratory homeostasis by monitoring various chemical concentrations in the blood such as oxygen, carbon dioxide, and proton (H+) levels. These chemoreceptors will detect changes accompanied with a lack of oxygen and signal to the medulla oblongata, which then stimulates breathing by increasing the contractions of the diaphragm. Since the diaphragm is the main respiratory muscle, we can see that answer choice [A] is correct. The heart is regulated by the autonomic nervous system, not peripheral chemoreceptors. We can eliminate answer choice [B]. The lungs are not directly responsible for breathing. Rather, the diaphragm and intercostal muscles work together for inhalation and exhalation. As discussed above, peripheral chemoreceptors signal to these respiratory muscles, so we can rule out answer choice [C]. Central chemoreceptors are the counterparts to peripheral chemoreceptors - both work together to influence breathing rate. Central chemoreceptors are located in the medulla oblongata and send signals in response to the acidity of the cerebrospinal fluid. However, the two do not signal to each other. Therefore we can eliminate answer choice [D]. The forebrain is one of three sections of the brain during embryonic development and gives rise to cerebrum. It is not involved in controlling breathing rate; therefore we can eliminate answer choice [E]. (respiratory system)

Peripheral chemoreceptors send signals to the medulla oblongata, which sends signals to the A. respiratory muscles. B. heart. C. lungs. D. central chemoreceptors. E. forebrain.

C. ductus arteriosus. The ductus arteriosus allows some blood from the pulmonary artery to flow into the descending aorta. Therefore, choice [C] is the correct answer. The ductus arteriosus is a crucial structure for a growing fetus because it alleviates the high blood pressure in the fetal pulmonary artery. Choice [A] is incorrect. Ductus venosus is present between the umbilical vein and the inferior vena cava. It allows incoming oxygenated blood from the placenta to merge with deoxygenated blood in the inferior vena cava. Choice [B] is incorrect. Foramen ovale is in the fetal heart located between the right and left atrium. It allows some sightly oxygenated blood to travel directly from the right atrium to the left atrium, by-passing the pulmonary circulation. Choice [D] is incorrect. Ligamentum arteriosum is a vestigial structure left behind by the ductus arteriosus. Choice [E] is incorrect. The umbilical vein directly carries oxygenated blood from the placenta to the fetus. Key Takeaways: * In the fetus, the ductus arteriosus alleviates high blood pressure in the fetal pulmonary artery by allowing some blood to flow into the descending aorta. * The ductus arteriosus is closed in adults. (circulatory system)

The fetal shunt that diverts blood from the pulmonary artery directly into the aorta is known as the A. ductus venosus. B. foramen ovale. C. ductus arteriosus. D. ligamentum arteriosum. E. umbilical vein.

C. concentrate bile. We must remember that the gallbladder does NOT produce bile, the liver produces bile. The gallbladder's main function is to concentrate and store bile until it is ready to be released into the duodenum. Therefore, we can rule out choices [A] and [B]. Choice [C] is the correct answer. Choices [D] and [E] are incorrect because the pancreas is the organ that produces and stores lipases. Key Takeaways: *The liver produces bile. *The gallbladder concentrates, stores, and releases bile. (digestive system)

The function of the gallbladder is to A. produce bile. B. metabolize bile. C. concentrate bile. D. store enzymatic lipases. E. produce enzymatic lipases.

B. H2O In order for the process of photosynthesis to begin, the cell must first produce ATP and NADPH for later use in the Calvin Cycle (where glucose is produced). These energy carriers are produced during the light-dependent reactions. To begin photosynthesis, a water molecule (H2O) is split to pass electrons to photosystem II and protons to the thylakoid lumen. The splitting of water (H2O) releases oxygen (O2). Additionally, protons (H+) are released by the splitting of water, which contribute to the concentration of H+ in the thylakoid lumen which drives ATP synthase. (photosynthesis)

The oxygen released during photosynthesis is produced from which of the following? A. ATP B. H2O C. NADPH D. C6H12O6 E. CO2

B. facilitated diffusion. Passive transport refers to the movement of molecules down a concentration gradient without using energy. Facilitated diffusion is a form of passive transport (meaning it does not require energy) that utilizes transport proteins to assist molecular movement across a barrier (such as a membrane). In this question, calcium is released from the sarcoplasmic reticulum through voltage-gated calcium channels, which represent a form of facilitated diffusion because 1) they do not require energy to shuttle calcium ions across the membrane and 2) transport proteins facilitate this movement. Only an initial depolarization is required to open up these channels. Thus, answer choice [B] is correct. Simple diffusion is another type of passive transport that involves diffusion of solutes across a selectively permeable membrane (no transport proteins involved). We can eliminate answer choice [A]. Active transport is the opposite of passive transport - it involves moving molecules against their concentration gradients through the use of energy, usually in the form of ATP. The calcium during this muscle contraction moves down its concentration gradient, so we can eliminate answer choice [C]. Bulk flow is the movement of a liquid and its substances down a force or pressure gradient. Since we are focusing on calcium ions in this question, we can rule out answer choice [D]. Dialysis is another form of passive transport very similar to simple diffusion in that it relies on separating molecules in different solutions based on size through a semipermeable membrane. However, it is not the most correct answer; we can eliminate answer choice [E]. (muscular system)

The sudden release of calcium from the sarcoplasmic reticulum during muscle contraction is an example of A. simple diffusion. B. facilitated diffusion. C. active transport. D. bulk flow. E. dialysis.

C. Acetylcholine for preganglionic; epinephrine and norepinephrine for postganglionic Preganglionic nerves leave the central nervous system and synapse onto ganglions, which are clusters of nerve cell bodies in the peripheral nervous system. They release preganglionic neurotransmitters onto postganglionic nerves, which branch off from ganglions and then release postganglionic neurotransmitters onto the effector organs. The sympathetic nervous system uses acetylcholine as a neurotransmitter for its preganglionic nerves, but releases epinephrine and norepinephrine onto effector organs from its postganglionic nerves. Note that the sympathetic nervous system also has preganglionic nerves that synapse on the adrenal medulla, the part of the adrenal gland that releases epinephrine and norepinephrine into the blood. Based on this information, we can see that answer choice [C] is correct. The parasympathetic nervous system relies solely on acetylcholine as a neurotransmitter for both its preganglionic and postganglionic nerves. Therefore choice [B] is incorrect because it describes the parasympathetic (not sympathetic) nervous system. (nervous system)

What are the preganglionic and postganglionic neurotransmitters for the sympathetic nervous system? A. Epinephrine and norepinephrine for both B. Acetylcholine for both C. Acetylcholine for preganglionic; epinephrine and norepinephrine for postganglionic D. Epinephrine and norepinephrine for preganglionic; acetylcholine for postganglionic E. Epinephrine for preganglionic; norepinephrine for postganglionic

C. Oligodendrocytes Glial cells are the non-neuronal cells in the nervous system that nourish, support, and protect the neurons and make to ensure the conditions are perfect for neuronal health. There are two subcategories of glial cells: microglia and macroglia. Microglial cells are the defenders of the CNS. They are specialized macrophages which protect the CNS. Macroglia can be further broken down into subtypes. Schwann cells: these are the cells that form myelin sheath in the peripheral nervous system. Oligodendrocytes: form the insulating myelin sheath in the central nervous system. Astrocytes: the most abundant type of glial cell. They help provide blood supply to CNS neuron, recycle neurotransmitters, and maintain proper ion levels. They also help to form the very important Blood-Brain-Barrier - a barrier which helps ensure the brain's cerebrospinal fluid (CSF) has unique, specific composition compared to composition of blood. Satellite cells: have similar function to astrocytes, but satellite cells function in the PNS. Ependymal cells: they create the cerebrospinal fluid which bathes the spinal cord and the brain. (nervous system)

What cell type forms the myelin sheath in the central nervous system? A. Schwann Cells B. Mircoglial cells C. Oligodendrocytes D. Astrocytes E. Ependymal cells

C. Kinetochore Sister chromatids are identical copies of a single chromosome that has been replicated; they are linked together by a specialized DNA region called the centromere. During cell division, the mitotic spindle pulls sister chromatids apart by attaching itself to kinetochores, proteins that surround the centromere. Thus, answer choice [C] is correct. As discussed above, the centromere is a region of DNA, not the proteins that the microtubules attach themselves to. We can eliminate answer choice [A]. Chiasmata are the physical points of contact between two non-sister chromatids during crossing over, which occurs in prophase I of meiosis. We can eliminate answer choice [B]. The spindle apparatus is also known as the mitotic spindle and refers to the entire system of microtubules that works together to pull the sister chromatids apart. Thus, answer choice [D] can be ruled out. A centriole is a hollow cylinder of microtubules. A pair of centrioles form a centrosome, which is responsible for creating and organizing the spindle apparatus. Therefore, we can finally rule out answer choice [E]. (cell division)

What do microtubules attach to when separating sister chromatids during cell division? A. Centromere B. Chiasmata C. Kinetochore D. Spindle apparatus E. Centriole

D. Endospore An endospore is a dormant, tough, non-reproductive structure produced by some bacterial species to preserve the cell's genetic material during a time of extreme stress. These bacteria can survive extreme temperatures or salinity levels. Endospores are resistant to desiccation, starvation, extreme temperature, enzymatic destruction, and chemical damage to ensure the survival of a bacterium. A.Teichoic acids The cell wall of gram-positive bacteria contains teichoic acids, which are polysaccharides that connect the peptidoglycan layer and plasma membrane for rigidity and structure. B. Endotoxin Bacterial endotoxins are a type of lipopolysaccharide (LPS), a class of phospholipids that are found in the outer membrane of gram-negative bacteria. The release of endotoxins occurs after the death and subsequent lysis of a bacterial cell. C. Endosperm The endosperm is the part of a plant seed that provides food for the growing plant embryo. It is not associated with bacteria. E. Cell wall The cell wall helps bacteria separate itself from the environment, but can be damaged in extreme environments. (diversity of life)

What helps some bacteria survive in extreme environments? A. Teichoic acids B. Endotoxin C. Endosperm D. Endospore E. Cell wall

E. Oxygen (O2) combines with two hydrogens and the electrons exiting the electron transport chain, to form H2O (water). It is critical to remember that it is oxygen which acts as the electron acceptor in this reaction - H2O is only the product of the reaction. In anaerobic respiration (no oxygen present), the cell will use fermentation to continue producing energy. In the absence of oxygen, animals and some bacteria use lactic acid fermentation. Pyruvate acts as the end electron acceptor. In the absence of oxygen, yeast and some bacteria use alcohol fermentation. Acetaldehyde acts as the end electron acceptor. (cellular energy)

What is the final electron acceptor in the electron transport chain? A. H2O B. ATP C. NADH D. FADH2 E. O2

E. Determine all coding regions of genes and their functions. Once a gene is sequenced, it must be annotated in order to make sense of it. Genome annotation is the process of: Identifying the locations of genes and all of the coding regions in a genome. Determining what those genes do. (molecular genetics)

What is the goal of genome annotation? A. Determine all 3D protein structure in a genome B. Analyze heritable epigenetic changes to a genome C. Study genomic changes over the course of generations D. Locate the corresponding DNA sequence of a known protein E. Determine all coding regions of genes and their functions.

B. Increased adrenocorticotropic hormone The hypothalamus secretes a few hormones to control the anterior pituitary. Some are hypothalamic-releasing hormones that instruct the anterior pituitary to release other hormones. Corticotropin-releasing hormone (CRH) is one such hormone that tells the anterior pituitary to release adrenocorticotropic hormone (ACTH). ACTH stimulates the adrenal cortex to release glucocorticoids, i.e. cortisol. During periods of long-term stress, cortisol prevents tissue buildup of macromolecules and breaks down storage molecules to generate immediate fuel. How does cortisol achieve this? It increases blood glucose level by targeting muscle cells, liver cells, and fat cells, thereby breaking down muscle, glycogen, and fat into glucose. The question poses a scenario in which an individual's prolonged starvation induces a period of stress. In response, the hypothalamus would release CRH in order to release more ACTH to activate the stress response, stimulate release of cortisol and increase blood sugar. (endocrine system)

What would be an expected response to low blood sugar? A. Decreased calcitonin B. Increased adrenocorticotropic hormone C. Increased insulin D. Increased glomerular filtration rate

E. Increase in human chorionic gonadotropin The endometrium is the inner uterine lining that an embryo implants into. Remember the two hormones that stimulate the thickening of the endometrium — estrogen and progesterone. Human chorionic gonadotropin (HCG) is a hormone secreted by the placenta if embryo implantation occurs. HCG prevents the corpus luteum from degenerating. Corpus luteum produces progesterone and estrogen. As a result, if the corpus luteum is maintained, progesterone and estrogen levels would rise and continue to thicken the endometrium. Choice [E] is the correct answer. Key Takeaways: * Estrogen and progesterone stimulate the thickening of the endometrium. * The corpus luteum sectretes estrogen and progesterone. * HCG is secreted by the placenta if implantation occurs to maintain the corpus luteum. (reproduction and developmental biology)

When fertilization occurs, which of the following maintains the thickness of the endometrium as the luteal phase of the menstrual cycle is ending? A. A surge in luteinizing hormone B. Breakdown of the corpus luteum C. Ovulation D. Increase in prolactin E. Increase in human chorionic gonadotropin

Capacitation refers to the final maturation step of sperm before fertilization. Uterine wall secretions trigger capacitation, which results in: Preparation of the sperm tip for the acrosomal reaction, which is an event that allows the sperm to penetrate the egg and initiate fertilization Increased permeability to calcium, which causes the flagella to beat faster and results in faster movement of the sperm Because uterine wall secretions trigger the start of capacitation, the sperm undergoes this event in the oviduct, also known as the Fallopian tube.

Where does capacitation take place? A. Oviduct B. Testes C. Epididymis D. Vagina E. Seminal Vesicle

C. Within the stroma Photosynthesis can be broken into two separate stages: the light dependent reactions and the light independent reactions (Calvin cycle). The Calvin cycle takes place in the chloroplast stroma. There, CO2 is fixed into carbon-carbon bonds, which will go on to produce glucose; this process is known as carbon fixation. (photosynthesis)

Where in the chloroplast do the light independent reactions of photosynthesis take place? A. Within the intermembrane space B. Within the thylakoid lumen C. Within the stroma D. In the thylakoid membrane E. On the stroma lamellae

B. The product at the end of a reaction inhibits the enzyme An enzyme is a biological catalyst; it increases the rate at which a chemical reaction occurs. However, the needs of each individual cell change over time, which means that enzymes need to be regulated to prevent the over-production of certain chemical products. Feedback regulation (feedback inhibition) describes a form of regulatory control where: The end product of a reaction pathway will inhibit one or more of the enzymes responsible for the production of the product. The result is that: Low level of product leads to a normal level of enzymatic activity, which will result in the production of the end product. Once the cell is saturated with the product, enzymatic activity will be inhibited. The push and pull of feedback regulation leads to the production of just the right amount of cellular products. (molecules and fundamentals of biology)

Which best describes the function of feedback regulation of enzymes? A. The enzyme produced is later used in the reaction B. The product at the end of a reaction inhibits the enzyme C. The enzyme increases the enthalpy of the products D. The enzyme decreases the enthalpy of the products E. The product of the reaction increases activity of the enzyme

D. Gluconeogenesis A good way to tackle questions such as these is to have a general understanding of what certain scientific words mean. For example, * The suffix "-lysis" describes some kind of cleavage or breakdown. * The suffix "-genesis" describes the creation of something. * The prefix "-gluco" means it's talking about glucose. * The prefix "-glyco" refers to glycogen. '-neo-' means new. Knowing this, we can determine that the process for synthesizing glucose would be named gluco-neo-genesis: glucose-new-creation. A. Beta-oxidation Beta-oxidation is a process by which fatty acids are cleaved in order to derive energy from lipids. B. Glycogenolysis Glycogenolysis describes the breakdown of glycogen into glucose. C. Glycolysis Glycolysis is the breakdown of glucose for the purpose of harnessing cellular energy. E. Glycogenesis Glycogenesis is the synthesis of glycogen from glucose molecules. (cellular energy)

Which cellular process can synthesize glucose molecules? A. Beta-oxidation B. Glycogenolysis C. Glycolysis D. Gluconeogenesis E. Glycogenesis

B. Mesoderm All components of the circulatory system, including the heart, are derived from the mesoderm. Be sure you know the germ layers and what is developed from them for your DAT. (reproductive and developmental biology)

Which germ layer develops into the circulatory system? A. Ectoderm B. Mesoderm C. Dermis D. Neural tube E. Endoderm

A. Human Forearm Homologous structures are structures that are derived from a common ancestor and are regardless of function (they may or may not perform the same function). A common example of homologous structures (that is worth memorizing) is the forearm (or wing) of a bird and the forearm of a human. Although they do not perform the same function, they are derived from a common ancestor, making them homologous structures. Therefore choice A. Human forearm is our correct answer. (evolution)

Which of following structures is homologous to the wing of a bird? A. Human Forearm B. Bat Wing C. Butterfly wing D. Hornet wing E. Shark fin

A. Enteropeptidase When food enters the duodenum, glands in the duodenum release enteropeptidase. Enteropeptidase activates trypsin, which in turn activates chymotrypsin. Both trypsin and chymotrypsin are pancreatic proteases. B. Pepsinogen D. Hydrochloric acid Pepsinogen is a zymogen (inactive precursor of an enzyme) that is released into the stomach. It is activated by stomach acid (which contains a high concentration of hydrochloric acid). C. Chymotrypsinogen E. Bicarbonate ion The pancreas secretes bicarbonate (neutralization), pancreatic amylase (starch → maltose), and proteases (proteins → amino acids). The pancreatic proteases are trypsin and chymotrypsin, which are initially released as zymogens (trypsinogen and chymotrypsinogen). Trypsin converts chymotrypsinogen to chymotrypsin. (digestive system)

Which of the following activates pancreatic proteases? A. Enteropeptidase B. Pepsinogen C. Chymotrypsinogen D. Hydrochloric acid E. Bicarbonate ion

D. The contraction of internal intercostal muscles There are two types of intercostal muscles that control breathing. When external intercostal muscle contract the rib cage expands and we inspire. When internal intercostal muscle contract, the rib cage contracts and it causes forced expiration. Only choice [D] accurately describes what happens during forced-expiration. We can eliminate choice [A] because it describes the opposite of what happens. Choices [B] is incorrect. Pulmonary surfactant indeed does decrease the surface tension in lungs. However, this helps the process of inspiration, not expiration. Choice [C] is incorrect. Pulmonary surfactant decreases the surface tension in lungs. Choice [E] is incorrect. The diaphragm does influence breathing. However, it contracts during inspiration to increase lung volume; it relaxes during both respiration and forced expiration. (respiratory system)

Which of the following aids in the process of forced expiration? A. The relaxation of internal intercostal muscles B. Pulmonary surfactant decreasing the surface tension in the lungs C. Pulmonary surfactant increasing the surface tension in the lungs D. The contraction of internal intercostal muscles E. The contraction of the diaphragm

D. Male gametophyte in a haploid cell Pollen grains are used by angiosperms to boost fertilization opportunities. A pollen grain contains a male gametophyte (microgametophyte) in a haploid cell. Choice [D] is the correct answer. Choice [A] is incorrect because gametophytes are always haploid. Recall the following alternation of generation diagram. Choices [B], [C], and [E] are incorrect because pollen grains contain a male gametophyte, not a sporophyte or spore.

Which of the following best describes a pollen grain? A. Male gametophyte in a diploid cell B. Sporophyte in a haploid cell C. Spore in a haploid cell D. Male gametophyte in a haploid cell E. Sporophyte in a diploid cell

A. Releases the egg The ovary produces multiple follicles. The Graafian follicle is the most developed of these follicles. The egg is released from the Graafian follicle during ovulation. Hence, [A] is the correct answer. Choice [B] is incorrect because this describes the role of FSH, the hormone that stimulates the development of follicles. Choice [C] is incorrect. The disintegration of the corpus luteum triggers menstruation as the levels of estrogen and progesterone decrease when fertilization does not occur. Choice [D] is incorrect. The site of fertilization can vary, but it typically occurs within the fallopian tube (oviduct). Choice [E] is incorrect. The Graafian follicle is the dominant follicle, which is the only follicle that does not undergo atrophy. While the Graafian follicle does eventually turn into the corpus luteum, which 'degenerates' (this could be thought of as an 'atrophy'), it is not the Graafian follicle that undergoes this process. (reproduction and developmental biology)

Which of the following best describes the role of a Graafian follicle? A. Releases the egg B. Stimulates the development of other follicles C. Initiates menstruation D. The site of fertilization E. A follicle which atrophies

This comparison question requires a broad general knowledge of the different phyla in the animal kingdom. See below for a summary table of all ten phyla with their respective excretory system. One way to remember this is to think of arthropods immediately when you see malpighian tubules. Moreover, flatworms and rotifers both use protonephridia + flame cells. In terms of complexity, octopus > earthworm > flatworm. Therefore, their excretory systems are nephridia, metanephridia, and protonephridia, respectively. (diversity of life)

Which of the following correctly matches the organism with its excretory system? (DONT LOOK AT DIAGRAM YET) A. Tapeworm; coxal glands B. Rotifers; flame cells C. Clam; malpighian tubules D. Scorpion; nephridia E. Ant; protonephridia

C. Echinodermata Protostomes include the animal phyla that have a blastopore during development that turns into the mouth. Deuterostomes include the animal phyla that have a blastopore that turns into the anus. 1. Phyla before Platyhelminthes are neither protostomes nor deuterostomes. 2. Platyhelminthes, Nematoda, Rotifera, Annelida, Mollusca, and Arthropoda are protostomes. 3. Only Echinodermata and Chordata are deuterostomes. (Diversity of Life)

Which of the following is a deuterostome? A. Nematoda B. Arthopoda C. Echinodermata D. Mollusca E. Annelida

E. Create a water barrier The stratum granulosum is one of the middle layers of the epidermis and contains keratinocytes (epidermal cells that secrete keratin). In the stratum granulosum, these keratinocytes also secrete lamellar bodies, which form a hydrophobic wall known as the skin's water barrier. Thus, answer choice [E] is correct. Epidermal stem cells are present in the deepest layer of the epidermis called the stratum basale (or stratum germinativum). These cells are in a different layer, so we can eliminate answer choice [A]. Innate immunity signaling in the skin is carried out by epidermal dendritic cells called Langerhans cells that are most densely located in the stratum spinosum, which is right under the stratum granulosum. Thus, we can rule out answer choice [B]. Skin pigmentation is a result of melanin produced by melanocytes, a specialized cell located in the stratum basale. We can rule out answer choice [C]. Mechanoreceptor cells in the epidermis are known as Merkel cells, which are also located in the stratum basale. Lamellar bodies do not act as mechanoreceptors, so we can eliminate answer choice [D]. (integumentary system)

Which of the following is a key function of the lamellar bodies produced by the stratum granulosum? A. Epidermal stem cells B. Innate immunity signaling C. Skin pigmentation D. Act as mechanoreceptors E. Create a water barrier

C. Highly acidic chyme in duodenum The pancreas plays many roles in the digestive system. One of them is to secrete bicarbonate ions to neutralize the acidic chyme. Hence, a malfunctioning pancreas would fail to produce bicarbonate and lead to highly acidic chyme in the small intestine. Choice [C] is the correct answer. Choice [A] is incorrect. Mucus is secreted by mucous cells and goblet cells in the stomach and small intestine, respectively. The pancreas does not directly affect mucus viscosity. Choice [B] is incorrect. Secretin is produced by the walls of the small intestine in response to acidic chyme to instruct the pancreas to produce bicarbonate ions. Choice [D] is incorrect. Bile is produced by the liver, not the pancreas. Choice [E] is incorrect. Peristalsis is controlled by the parasympathetic nervous system, not by the pancreas. (digestive system)

Which of the following is a possible consequence of a malfunctioning pancreas? A. Viscous mucus B. Inadequate production of secretin C. Highly acidic chyme in duodenum D. Low bile production E. Slow peristalsis

D. T cells Cell-mediated immunity is part of the adaptive immune response that, as the name suggests, is carried out by cells, rather than antibodies. In humans, T cells carry out this response and can be activated in two ways: if an immature T cell is presented with an antigen by MHC I, they become cytotoxic T cells, otherwise known as CD8 cells. Activated CD8 cells release granzymes and perforin to kill pathogens. if an immature T cell is presented with an antigen by MHC II, they become helper T cells, otherwise known as CD4 cells. Activated CD4 cells release interleukin to boost the adaptive and innate immune response, and cytokines to activate other B and T cells in addition to attracting innate immune cells to infected sites. A. Granulocytes Granulocytes are cells within the innate immune system that are characterized by the presence of specific granules in their cytoplasm. The four types of granulocytes are: Neutrophils Eosinophils Basophils Mast cells B. B cells B cells, in contrast to T cells, carry out antibody-mediated immunity by controlling the production and release of antibodies. C. Histamine Histamine is a chemical that is involved in innate immunity. It dilates nearby capillaries to increase blood flow in addition to increasing the capillary's permeability to fluids and immune cells. Histamine is a key component of the inflammatory pathway. E. Platelets Platelets, otherwise known as thrombocytes, are anucleate cell fragments that are responsible for clotting. Upon activation at a site of injury, platelets release clotting factors that convert fibrinogen to fibrin, which forms a clot to stop bleeding. (human immune system)

Which of the following is involved in cell-mediated immunity? A. Granulocytes B. B cells C. Histamine D. T cells E. Platelets

C. Downregulated p53 gene Tumor suppressor genes are genes that regulate a cell during cell division and replication. When a tumor suppressor gene is mutated or downregulated, it results in a loss or reduction in its function. Keep in mind that loss-of-function mutations in both copies of these genes are required for cancer causing, null tumor suppressor alleles. For example, p53 is a tumor suppressor gene that is known as the 'guardian of the cell'. The downregulation of p53 leads to an increase in the frequency of cell division. Choice [C] is the answer. [Choice A]: During the G1 phase of interphase, the cell physically grows in preparation of a future division. If conditions are not favorable for a division, it will enter the G0 phase. The G0 phase is a sort of "hangout spot" where cells that are not ready to divide just "do their thing." Cells that are ready to divide will progress to the S phase. [Choice B]: Cyclin dependent kinase (CDK) functions to stimulate cell division. Therefore, inhibition of CDK activity leads to a decrease in the frequency of cell division. [Choice D]: Proto-oncogenes are normal genes involved in cell division and regulation. If they experience a gain-of-function mutation, this can cause the proto-oncogene to become an oncogene. Oncogenes are genes that can transform a normal cell into a cancerous cell, by either making too much protein or making a protein product that is too active. (cell division)

Which of the following is most likely to lead to uncontrolled cell proliferation? A. Entry to the G0 phase of the cell cycle B. Inhibited cyclin dependent kinase C. Downregulated p53 gene D. Loss-of-function mutations of proto-oncogenes

D. Stimulated for release by cholecystokinin Bile is produced by the liver and sent to the gall bladder for storage. When fat enters the duodenum, the duodenum produces cholecystokinin (CCK). CCK stimulates the gall bladder to contract and release bile into the duodenum to help emulsify fat, which can then be digested by lipases. (digestive system)

Which of the following is true of bile? A. produced in the gallbladder B. Functions to enzymatically break down fat C. Released into the stomach D. Stimulated for release by cholecystokinin E. Broken down into heme

C. Megakaryocytes are the precursors to platelets Megakaryocytes are large bone marrow cells that are the precursors to platelets. Fragments of the megakaryocyte break off to form platelets. Platelets are heavily involved in the clotting cascade. A.Contain multiple nuclei Platelets do not contain a nucleus. This quality is referred to as anucleate. Red blood cells do not contain a nucleus either. B. Cell fragments of old red blood cells Cell fragments of old red blood cells are broken down in the liver. Platelets are derived from the fragmentation of megakaryocytes. D. Activated platelets release fibrin Activated platelets release thromboplastin (also known as tissue factor). Thromboplastin converts the precursor (inactive) prothrombin into its active form, thrombin. (circulatory system)

Which of the following is true of platelets? A. Contain multiple nuclei B. Cell fragments of old red blood cells C. Megakaryocytes are the precursors to platelets D. Activated platelets release fibrin

B. Immunofluorescence microscopy Immunofluorescence microscopy is a technique used to identify the localization of proteins of interest. This technique uses fluorescent tags (fluorophores) attached to antibodies that target the protein of interest (the antigen), which allows researchers to visualize the distribution of target proteins. Because it can be used to view specific proteins in a cell (like p53), [B] is the correct answer. A. Enzyme-linked immunosorbent assay Enzyme-linked immunosorbent assay (ELISA) is a technology to determine if a specific antigen exists in a person. Antibodies are placed into a microtiter plate and if they bind to the specific antigen that is being tested for, there will be a color change in the microtiter plate. This indicates that the person has the disease/antigen. Although ELISA can be used to detect the presence of proteins in a person, it cannot be used to visualize proteins inside a cell. C. Pulse-chase analysis Pulse-chase experiments are useful for researchers that want to know more about how proteins move through a cell. It gives them information about gene expression for any given cell type and allows them to see the movement of labeled proteins. However, these radioactively labeled amino acids will be incorporated into many proteins, not just p53. Therefore, this technique wouldn't be specific enough to help researchers detect the presence of a specific protein. D. Southern blotting Blotting is a technique used to separate and identify specific molecules using electrophoresis and probing. Southern blotting is used to identify specific DNA sequences, which would not be useful for the detection of p53. Western blotting, on the other hand, can be used to identify specific proteins. E. Centrifugation Centrifugation spins a heterogeneous sample in a laboratory apparatus called a centrifuge. The cell contents then separate based on mass, density, and shape. The densest and most compact particles will sediment to the bottom of the centrifuge tube first. Centrifugation can be used to separate proteins, but it is not refined enough to detect the presence of a specific protein. (microscopy and lab techniques)

Which of the following lab techniques can be used to detect the presence of p53 protein inside a cell? A. Enzyme-linked immunosorbent assay B. Immunofluorescence microscopy C. Pulse-chase analysis D. Southern blotting E. Centrifugation

C. Sympathetic nervous system and adrenal medulla The sympathetic nervous system is one of two parts of the autonomic nervous system (the other being the parasympathetic nervous system) and is our bodies main mechanism to prepare for the "flight or fight response." When activated, the sympathetic nervous system performs the following functions: * Increases heart rate * Increases blood pressure * Increases breathing rate * Increases pupil size * Slows gastric emptying The adrenal gland sits on top of the kidney. The gland can be divided into two main structures: the outer cortex and the inner medulla. The cortex and medulla of the adrenal gland each produce different hormones. The adrenal medulla produces catecholamines (epinephrine and norepinephrine), which are consistent with the body's "fight or flight" response and are considered stress hormones. Their effects on target organs are similar to their role in the sympathetic nervous system but have a longer-lasting effect. Their effects include the conversion of glycogen to glucose (increasing blood glucose levels), increased lipolysis, vasoconstriction to the internal organs and skin but vasodilation to the skeletal muscles, and increased heart rate. The adrenal medulla is primarily stimulated by the activation of the sympathetic nervous system. When activated, the SNS signals to the adrenal medulla to release A. Sympathetic nervous system and adrenal cortex The adrenal cortex produces mineralocorticoids, glucocorticoids, and androgens. The adrenal cortex does not participate in the "flight or fight" response. B. Sympathetic nervous system and thyroid gland The thyroid gland produces T3, T4, and calcitonin. The thyroid gland does not participate in the "flight or fight" response. D. Parasympathetic nervous system and adrenal cortex The adrenal cortex produces mineralocorticoids, glucocorticoids, and androgens. The adrenal cortex does not participate in the parasympathetic nervous system's "rest and digest" response. E. Parasympathetic nervous system and adrenal medulla The adrenal medulla primarily functions to prepare us for our "flight or fight" response. Contrarily, the parasympathetic nervous system is concerned with the opposite, where it instead prepares us for our "rest and digest" response. (endocrine system)

Which of the following pairs of structures have similarity in function? A. Sympathetic nervous system and adrenal cortex B. Sympathetic nervous system and thyroid gland C. Sympathetic nervous system and adrenal medulla D. Parasympathetic nervous system and adrenal cortex E. Parasympathetic nervous system and adrenal medulla

C. Posterior pituitary and adrenal cortex The origin and effects of hormones is a common topic on the DAT. Here, we are looking for two structures that target the same organ with different hormones. The posterior pituitary releases ADH, which allows the kidneys to reabsorb more water. The adrenal cortex releases mineralocorticoids, such as aldosterone, which affects the kidney to increase salt reabsorption (which in turn increases water absorption as well due to changes in osmolarity). The pancreas releases glucagon (increase blood glucose) from alpha cells and insulin (decrease blood glucose) from beta cells. The thyroid controls general metabolism and releases calcitonin, which lowers blood calcium. The parathyroid releases PTH (parathyroid hormone), which increases blood calcium. The anterior pituitary releases FSH, LH, ACTH, TSH, prolactin, and growth hormone. The testes produce testosterone. (endocrine system)

Which of the following pairs of structures target the same organ with different hormones? (DONT LOOK AT DIAGRAM YET) A. Pancreas and thyroid B. Testes and posterior pituitary C. Posterior pituitary and adrenal cortex D. Adrenal medulla and parathyroid E. Adrenal cortex and pancreas

B. B → D → A The cell cycle is broken down into the G1, S, G2, and M phases. G0 is a "resting phase" that exists outside of the cell cycle. Bootcamp Mnemonic: Go = Gap Phase 1 (G1) of interphase Sam = Synthesis Phase of interphase Go = Gap Phase 2 (G2) of interphase Make = Mitosis of the M phase Cake = Cytokinesis of the M phase It is important to note that the condensation of chromatin into chromosomes occurs during prophase, while cytokinesis starts during late anaphase in animals, and telophase in plants. The correct sequence of events after cell division (completion of the M phase) would be B → C → E → D → A, of which only answer choice [B] correctly follows. Key Takeaway: * After cell division, the cell cycle enters G1, then S, then G2, and concludes with the M phase. * Chromatin condenses into chromosomes during prophase of mitosis. * Cytokinesis, the physical process of cell separation, starts during late anaphase in animals, and telophase in plants. (cell division)

Which of the following represents the correct order of stages after cell division? A. Cytokinesis B. G1 C. Synthesis D. Condensing of chromatin E. G2 F. G0 A. A → C → E B. B → D → A C. F → B → E D. C → D → B E. F → D → B

E. Vital capacity The total lung capacity is composed of the vital capacity and residual volume. Vital capacity refers to the greatest volume of air that the lungs can possibly exhale after a maximum inhalation while residual volume refers to the minimum amount of air needed in the lungs to prevent them from collapsing. Vital capacity is much larger than residual volume, so answer choice [E] must be correct. Tidal volume refers to the amount of air that is inhaled or exhaled during normal breathing. Since only a moderate volume of air moves through the lungs during normal breathing, answer choice [A] can be ruled out. Inspiratory reserve volume represents the amount of air that can still be taken in after a normal inhalation. This is about half of vital capacity, so answer choice [B] can be eliminated. Functional residual volume refers to the air still left in the lungs after a normal exhalation. This is also about half of vital capacity, so answer choice [C] can be eliminated. Residual volume is only present in the lungs to prevent them collapsing and is not responsible for the large amounts of air flow that takes place. Answer choice [D] can finally be ruled out. (respiratory system)

Which of the following represents the greatest volume? A. Tidal volume B. Inspiratory reserve volume C. Functional residual capacity D. Residual volume E. Vital capacity

D. Fats Fats store the most amount of energy in the body. They store roughly double the amount of energy carbohydrates (starch, glycogen, cellulose) store, gram for gram. The reason our body prefers to burn glucose is because it is easier to use in respiration and it is more readily available. Key Takeaways: * Fats store 9 calories of energy per gram, while proteins and carbohydrates store 4 calories per gram. (cellular energy)

Which of the following stores the most amount of energy, gram for gram? A. Starch B. Glycogen C. Polypeptides D. Fats E. Glucose

B. B antigen; A antibodies If we exclude the Rh factor, there are 4 blood types (A, B, AB, O). However, there are only two types of antigens and antibodies (A and B). Keep in mind this rule: you will produce antibodies for the antigen that you don't have. The person in the question has type B blood, which means that he only produces B antigens. According to the rule of thumb, he will produce antibodies for the antigen that he doesn't have. As a result, he would have B antigens and A antibodies. Choice [B] is the correct answer. (circulatory system)

Which of the following would be present in a person with type B blood? A. B antigen; B antibodies B. B antigen; A antibodies C. A antigen; A antibodies D. A antigen; B antibodies E. Both A and B antigens; no antibodies

A. Morula Recall that embryogenesis in mammals is split into distinct stages called the morula, blastula, and gastrula. The initial zygote, a single fertilized cell, will begin to divide in order to begin the process of growth. Around the 12-16 cell mark, the zygote is now known as a morula. B. Epiblast The epiblast is one of the two distinct layers of the inner cell mass, a ball of cells found in the middle of a blastocyst. The epiblast goes on to contribute to the main embryo and form a structure called the primitive streak. C. Blastomere Blastomeres refer to the individual cells created from the dividing zygote into the morula stage. Each individual blastomere splits without increasing in size, meaning the morula is actually the same size as the initial zygote. In humans, blastomeres are totipotent, meaning a single blastomere can go on to produce an entire human. D. Blastula The blastula phase of embryogenesis typically starts around 128 cells. It is characterized by the formation of a hollow, fluid-filled cavity, called a blastocoel, in the middle of the mass of dividing cells. E. Gastrula The gastrula is characterized by the invagination of the epiblast into the primitive streak, forming three distinct germ layers. This happens after the blastula phase. (reproduction and developmental biology)

Which of these represents an embryo during the 12-16 cell stage? A. Morula B. Epiblast C. Blastomere D. Blastula E. Gastrula

C. Left ventricle It is helpful to remember the diagram of the heart and the names of each region. The most muscular part of the heart will likely be the section that needs to create the most pressure. We must recall that the left ventricle pumps blood out to the entire body, so it will require the most muscle. Thus, we can see that answer choice [C] is correct. The left atrium takes oxygenated blood in from the pulmonary veins and delivers the blood to the left ventricle. We can rule out answer choice [A]. The right atrium takes low pressure blood from the body and delivers it to the right ventricle. Answer choice [B] can be ruled out. The right ventricle accepts the low pressure blood from the right atrium and sends it to the lungs. Thus, answer choice [D] can be ruled out. Although the aorta has a large amount of smooth muscle to accommodate high pressure blood entering it, it is the left ventricle is responsible for pumping the blood and creating high pressure. The left ventricle is more muscular, and we can rule out answer choice [E].

Which region of the heart is typically most muscular? A. Left atrium B. Right atrium C. Left ventricle D. Right ventricle E. Aorta

A. Femur and tibia When seeing that the anterior cruciate ligament is harmed, we now know we're looking for a ligament. Tendons connect muscles to bones. Ligaments connect bones together. Therefore we're looking for two bones in the answer choices, as this is what a ligament connects. The anterior cruciate ligament connects the femur, the thigh bone (and the largest bone in the human body), to the tibia, a large bone in the lower leg. (skeletal system)

While crossing the street, Paul is hit by a car and suffers an injury to his knee. Upon screening by a doctor, it is determined that he has torn his anterior cruciate ligament. What two structures does this ligament connect? A. Femur and tibia B. Patellar bone to quadriceps C. Gastrocnemius to femur D. Gastrocnemius to hamstrings

D. Component A is more soluble within the solvent. Chromatography is a laboratory technique used to separate a heterogeneous sample into individual bands. Therefore, answer [C] is incorrect. In this question, component A and component B each produce their own bands depending on how they interact with the solvent (mobile phase) that they are traveling in. These variable interactions are based on the differential solubility of the components within solvent (the mobile phase) vs. the apparatus (the stationary phase). If component A travels a further distance than component B, component A must be more soluble within the solvent and must have a lower affinity for the stationary phase. Therefore [D] is our answer, and [A] is incorrect. From the information given in the question we are not able to conclude whether the mobile phase is a polar or nonpolar solvent. Therefore, we can eliminate [B] and [E].

While performing chromatography on a sample of components A and B, component A travels further than component B. Which of the following conclusions can be drawn from this experiment? A. Component A has greater affinity for the stationary phase. B. The sample is nonpolar while the solvent is polar. C. Component A and B form a homogenous solution. D. Component A is more soluble within the solvent. E. Component A is nonpolar while component B is polar.