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A chemist needs to add 5 μL of a reagent to a reaction solution. Which of the following is the best tool to accomplish this? A volumetric pipette A micropipette A volumetric flask A 1-mL pipette ---------- Correct Answer ---------- Answer: A micropipette In chemistry, it is important to select the most appropriate glassware and measurement devices. This means selecting a device that is capable of accurately measuring and dispensing the desired amount of reagent. In the choices above, none of the other choices would allow the chemist to accurately measure 5 μL. A micropipette is used to measure extremely small volumes of liquids, typically on the microliter scale, hence the name! Which of the following processes correctly describe the formation of new cells in order to replace worn-out and damaged cells during injury? Meiosis Mitosis Exocytosis Endocytosis ---------- Correct Answer ---------- Answer: Mitosis
- Mitosis and meiosis are two types of cell division.
- Mitosis is a process where a single cell divides into two identical daughter cells. The major purpose of mitosis is to replace worn-out and damaged cells.
- Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of genetic information. The purpose of meiosis is to create sex cells - sperm in males, eggs in females.
- Exocytosis is the cellular process of transporting substances out of the cell.
- Endocytosis is the cellular process of taking substance into the cell. Which of the following statements about osmosis is false? Osmosis is the spontaneous net movement of water molecules
Osmosis involves a selectively permeable membrane Osmosis moves water molecules mostly through the phospholipid heads of the cell membrane Osmosis involves the movement of water from an area of high concentration of water to an area of low concentration of water ---------- Correct Answer ---------- Answer: Osmosis moves water molecules mostly through the phospholipid heads of the cell membrane Osmosis is the spontaneous movement of water molecules through a selectively permeable membrane. The water moves along a concentration gradient, which means that it moves from areas of higher water concentration to areas of lower water concentration. (When considering solutes - the substance dissolved in the water - the water moves from a region of low solute concentration to a region of high solute concentration.) The water moves across the membrane until there are equal concentrations of water and solute on each side. The water molecules achieve this by moving across a selectively permeable membrane that transports the water through proteins called aquaporins. Which of the following organ systems is correctly paired with its function? Excretory/ transport of substance to all tissues of the body Circulatory/ obtaining nutrients necessary for growth, energy and normal body processes Endocrine/ regulation of homeostasis through hormone signaling Digestive/ waste elimination ---------- Correct Answer ---------- Answer: Endocrine/ regulation of homeostasis through hormone signaling
- The Endocrine system is responsible for regulating homeostasis through hormone signaling.
- The Digestive system is responsible for obtaining nutrients through the breakdown and absorption of food.
- The Circulatory system is responsible for transport of substance to all tissues of the body.
- The Excretory system is primarily responsible for waste elimination. A lung with a low level of compliance could be best described as _____________. a stiff lung requiring extra work to accomplish normal breathing. A lung with a high elasticity but with damaged alveoli. a highly elastic lung allowing breathing occur with reduced work. a lung with normal function. ---------- Correct Answer ---------- Answer: a stiff lung requiring extra work to accomplish normal breathing.
- Lung compliance is the property of the lung that allows it to stretch and recoil. Both appropriate stretch and recoil are necessary for proper lung function, thus compliance that is too high or too low can negatively affect function. In a lung with low compliance, or a stiff lung, extra work will be required to overcome the stiffness of the lung and breathe sufficient air in.
- A stiff lung will not operate normally as sufficient air will not be able to be taken in without extra effort to overcome the resistance of the lung.
- The low compliance of the lung indicates that it's elastic properties are reduced, thus it will not be highly elastic.
- A lung with low compliance will not have high elasticity; instead it will be stiff. There may be damaged alveoli but this may not always be the case. Which of the following is a unique property of water? When freezing, water molecules can form hydrogen bonds more easily Its low surface tension Its exceptional low heat of vapourization Its volume decreases when freezing ---------- Correct Answer ---------- Answer: When freezing, water molecules can form hydrogen bonds more easily
- Besides mercury, water has the highest surface tension for all liquids. Water's high surface tension is due to the hydrogen bonding in water molecules. When freezing, molecules within water begin to move around more slowly, making it easier for them to form hydrogen bonds with each other and eventually arrange themselves into an open crystalline, hexagonal structure. Because of this open structure as the water molecules are being held further apart, the volume of water (now ice) increases about 9%. This is why ice floats on liquid water.
- Water also has an exceptionally high heat of vaporization. Vaporization occurs when a liquid changes to a gas. Dissolved oxygen (DO) is an important indicator of water quality, and oxygen levels that are too high or too low can harm aquatic ecosystems. A biologist noticed that fish were dying in a local lake and was concerned that the DO levels were too low to support aquatic life due to extremely high temperatures that summer. To measure the DO levels, she brought back several lake water samples to her laboratory to measure the DO concentration as a function of temperature. To do this, she heated several samples of lake water to various temperatures and then measured the DO concentration in each sample. Some samples were kept at the outdoors temperature. Which of the following is the independent variable? Volume of water Temperature
Dissolved oxygen concentration Location of the lake ---------- Correct Answer ---------- Answer: Temperature The independent variable is the variable that is controlled during an experiment to see how it influences the dependent variable. In this case, the temperature of the water was changed to see how it influenced the DO concentration. Isotopes are __________. versions of one element with a different number of protons versions of one element with a different number of neutrons types of valence shells special orbitals in metal elements ---------- Correct Answer ---------- Answer: versions of one element with a different number of neutrons Isotopes are variants of an element where the number of neutrons are different from a normal atom of that particular element. All isotopes of an element will have the same number of protons (changing the number of protons would change the element), but will have different numbers of neutrons in each isotope. For example, Carbon-14 is an isotope of Carbon. A "normal" carbon atom would have 6 protons and 6 neutrons. Carbon-14 has 6 protons and eight neutrons. Which of the following needs to be present in order for a substance to be considered a nucleotide? 5 carbon sugar, nitrogenous base, phosphate group Ribose, amino acid, phosphate Deoxyribose, adenosine, triphosphate 5 carbon sugar, nitrogenous base, triphosphate ---------- Correct Answer ---------- Answer: 5 carbon sugar, nitrogenous base, phosphate group Nucleotides are the building blocks of both DNA and RNA. All nucleotides consist of three main components: a 5 carbon sugar, (either ribose or deoxyribose), a nitrogenous base and a phosphate group. Which of the following is a heterotrophic organism with a genome stored in DNA? Virus Plants Human Algae ---------- Correct Answer ---------- Answer: Human
- Humans are heterotrophic organisms, which means that they cannot make their own food. Instead, they rely on other sources of nutrition, such as plants and animals. Humans have their genome stored in DNA.
- Plants and algae are autotrophic (they can create their own food/nutrition) and have their genome stored in DNA.
- A virus, on the other hand, is neither autotrophic nor heterotrophic, and has RNA as genetic material. Which of the following is incorrect about muscle contraction? Muscle contraction requires ATP. Neurotransmitters stimulate muscle contraction. Actin and myosin filaments shorten during contraction. Sarcomeres shorten during contraction. ---------- Correct Answer ---------- Answer: Actin and myosin filaments shorten during contraction. Muscle contraction occurs upon stimulation of neurotransmitters released in the neuromuscular junction. The process requires ATP and involves shortening of sarcomeres by the sliding of actin and myosin past each other. The length of actin and myosin filaments does not change during contraction. Which of the following statements is true? A phase diagram is a graph of physical states of a substance under varying pressures as a function of temperature. Melting is the phase transition of a substance from a gas to a liquid. The triple point of a substance is the temperature and pressure at which three phases of a substance may coexist in thermodynamic equilibrium. Melting is the transition of a substance from a liquid to a solid. ---------- Correct Answer - --------- Answer: The triple point of a substance is the temperature and pressure at which three phases of a substance may coexist in thermodynamic equilibrium.
- In thermodynamics, the triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in equilibrium.
- Melting is the physical process in which a solid transitions in a liquid. This happens when the internal energy of the solid increases (usually due to the application of heat or pressure), which in turn increases the substance's temperature up to the melting point.
- A phase diagram is a type of chart used to show conditions (pressure, temperature, volume, etc.) at which thermodynamically distinct phases (such as solid, liquid or gaseous states) occur and coexist at equilibrium. Which of the following conditions occurs when a blood vessel in the brain becomes blocked?
Migraine Myocardial infarction Aneurysm Stroke ---------- Correct Answer ---------- Answer: Stroke
- A stroke can result if a blood vessel in the brain becomes blocked, either by a clot or other type of embolism. When this occurs, blood flow to the affected area of the brain is stopped, and that area of the brain loses function, sometimes permanently.
- A myocardial infarction (heart attack) also occurs as a result of a blocked vessel, however this occurs in the heart, not the brain.
- An aneurysm is the enlargement and weakening of a blood vessel, and is susceptible to rupture. While this can occur in the brain, causing a hemorrhagic stroke, it is not due to a blockage in the blood vessel.
- Migraines are painful headaches that can last for several hours to days. The causes of migraines are not fully understood, but there are several environmental and physiological factors that may contribute to their onset. While migraines can be severely painful, they are not associated with blocked blood vessels in the brain. In the sliding filament theory of muscle contraction, which of the following ions bind to troponin and initiate actin-myosin binding? Sodium Potassium Calcium Iron ---------- Correct Answer ---------- Answer: Calcium In the sliding filament theory of muscle contraction, calcium (ca) binds to troponin, causing conformational change that exposes the myosin-binding site, hence promoting the binding of actin-myosin. Where are the glomeruli and Bowman's capsules found? Renal cortex Renal pelvis Ureter Renal column ---------- Correct Answer ---------- Answer: Renal Cortex The glomeruli and Bowman's capsules are part of the nephrons, and are found in the renal cortex.
The respiratory system is composed of organs that facilitate gas exchange between the blood and the external environment. Which of the following describes the group of organs that function during gas exchange? Organelle Organ Tissue Organ System ---------- Correct Answer ---------- Answer: Organ system
- Tissues are a collection of specialized cells that perform a specific functions (e.g. protection, support, nerve conduction and movement).
- A group of tissues that has a specialized function is referred to as an organ.
- A group of organs that work together to perform several related functions is an organ system. Which of the following parts and divisions of the nervous system is correctly paired? autonomic division/ peripheral nervous system autonomic division/ central nervous system spinal cord/ peripheral nervous system brain/ peripheral nervous system ---------- Correct Answer ---------- Answer: autonomic division/ peripheral nervous system The 2 major divisions of the nervous system are the central and peripheral divisions. The central nervous system is comprised of the brain and spinal cord. The peripheral nervous system is made up of the somatic and autonomic divisions. Which of the following is not a monosaccharide? Glucose Ribose Maltose Glyceraldehyde ---------- Correct Answer ---------- Answer: Maltose
- Monosaccharides, also known as simple sugars, are the most basic units of carbohydrates. This means they cannot be further broken down into simpler chemical compounds.
- Disaccharides are sugars formed when two monosaccharides are joined together.
- Ribose, Glyceraldehyde, and glucose are all monosaccharides.
- Maltose is a disaccharide made up of two glucose molecules.
Balance the equation: CH4 + Cl2 → CCl4 + HCl 2 CH4 + Cl2 → 2 CCl4 + HCl CH4 + Cl2 → CCl4 + HCl 2 CH4 + 2 Cl2 → 2 CCl4 + 2 HCl CH4 + 4 Cl2 → CCl4 + 4 HCl ---------- Correct Answer ---------- Answer: CH4 + 4Cl2 → CCl4 + 4HCl To balance equations, it is helpful to write down the number of atoms of each element present in both the reactants and products. Change the coefficients of the reactants and products until the same number of atoms of each element is present on both sides of the reaction arrow. The molecular formula for baking soda is NaHCO3 This molecule is made up of 6 ____ and 4 __________? atoms; electrons atoms; elements elements; atoms electrons; atoms ---------- Correct Answer ---------- Answer: atoms; elements The formula consists of one sodium (Na) atom, one hydrogen (H) atom, one carbon (C) atom and three oxygen (O) atoms - in total 6 atoms. It contains 4 different elements - sodium, hydrogen, carbon and oxygen. Which of following glands in the skin is not correctly paired with its secretion? Apocrine sweat glands/ odoriferous perspiration Ceruminous glands/ sebum Eccrine glands / perspiration necessary for evaporative cooling Sebaceous glands / oil ---------- Correct Answer ---------- Answer: Ceruminous glands/ sebum
- Ceruminous glands produce cerumen/ ear wax.
- Apocrine sweat glands produce odoriferous perspiration
- eccrine glands secrete perspiration necessary for evaporative cooling
- Sebaceous glands secrete oil or sebum Joe is blood type A and Ivone is type O. Their son Tomas is type A. What could be Tomas's genotype? There is not enough information to say for certain
iA/i iB⁄ iA i⁄i ---------- Correct Answer ---------- Answer: iA/i A blood type is a classification of blood, based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells.
- Type A blood means that there are only A proteins present. Genotypes iAiA (AA) and iAi (AO) will be type A blood and will produce only A proteins.
- Type B blood means that there are only B proteins present. Genotypes iBiB (BB) and iBi (BO) will be type B blood and will produce only B proteins.
- Type AB blood means that there are both A and B proteins present. The genotype iAiB (AB) will be type AB blood and will produce both A and B proteins.
- Type O blood means that there are no proteins present. The genotype ii (OO) will be type O blood and will not produce any proteins.
- Each biological parent donates one of two ABO genes to their child. The A and B genes are dominant and the O gene is recessive. As it is in our example, if an O gene is paired with an A gene, the blood type will be A. Their genotype is either AA (iAiA) or AO (iAi). The basic function of the renal system includes filtration, secretion, reabsorption, and excretion. Which of the following substances is secreted by the nephrons and can be found in the filtrate that is eventually excreted? Amino Acids Sodium Glucose Creatinine ---------- Correct Answer ---------- Answer: Creatinine
- Amino acids, sodium and glucose are normally reabsorbed in the proximal portion of the renal tubules.
- Creatinine, which is used to assess glomerular filtration, is filtered in the glomerulus and also secreted by the tubules. Which of the following can be classified as an intensive property? Mass Entropy Density Volume ---------- Correct Answer ---------- Answer: Density
- An intensive property is any characteristic of matter that does not depend on the amount of the substance present. Examples of intensive properties are density and color. This is because no matter how much or little you have of a substance, the color and the density of that substance are the same. If you have one ounce of orange juice or three gallons of orange juice, it will still be the color orange and will have the same density.
- An extensive property is any characteristic of matter that depends on the amount of matter being measured. Examples of extensive properties are mass and volume. If you have one ounce of orange juice, the mass and volume of the orange juice would be different than if you had three gallons of orange juice.
- Entropy refers to the degree of disorder within a system (how random and unpredictable something is). It is measured by the amount of energy unavailable in a closed thermodynamic system. Entropy can change depending on the size of the system and the amount of matter within it which makes it an extensive property. Which of the following is the result of deficient production of thyrotropin-releasing hormone? There will be insufficient production of growth hormone The parathyroid gland will be stimulated to overproduce parathyroid hormone The thyroid gland will produce an insufficient amount of thyroid hormones The pituitary gland will produce excessive amounts of thyroid-stimulating hormone ------- --- Correct Answer ---------- Answer: The thyroid gland will produce an insufficient amount of thyroid hormones The Thyrotropin-releasing hormone (TRH) stimulates the pituitary gland to release TSH (thyroid-stimulating hormone), which in turn stimulates the thyroid gland to secrete the thyroid hormones, T3 and T4. Deficient production of TRH will result in an insufficient production of thyroid hormones in the thyroid. Which of the following is true? The male gametes are called sperm and contain half of a set of chromosomes. The male gametes are called eggs and contain full set of chromosomes. The female gametes are called ovaries and contain half of a set of chromosomes. The female gametes are called ova and contain full set of chromosomes. ---------- Correct Answer ---------- Answer: The male gametes are called sperm and contain a half set of chromosomes.
- The ova, or eggs, are the female gametes and contain half of a set of chromosomes, while sperm are the male gametes which also contain half of a set of chromosomes.
- Ovaries are the female reproductive organs, which produce the female gametes.
- In males, the reproductive organs responsible for producing gametes are the testes. Which of the following statements is true about covalent bonds? Covalent bonds form from the sharing of electrons between atoms Sigma bonds are the weakest covalent bonds The covalent bond between H-Cl is nonpolar Covalent bonds aren't affected by the electronegativity of the atoms ---------- Correct Answer ---------- Answer: Covalent bonds form from the sharing of electrons between atoms
- A covalent bond is a chemical bond that is formed when two atoms share electrons in their outermost shells. These shared electrons are called shared pairs.
- Sigma bonds are the strongest covalent bonds and are due to head-on overlapping of orbitals on two different atoms. A single bond is usually a sigma bond.
- Covalent bonds are also affected by the electronegativity of the connected atoms, which determines the polarity of the bond. Two atoms with equal electronegativity will make nonpolar covalent bonds such as H-H. A molecule that does not share electrons "equally," such as H2, creates a polar bond. A polar bond is characterized by one of the atoms in the molecule having a stronger "pull" on the shared electrons. This results in some atoms in the molecules having a slightly negative charge and others having a slightly positive charge. In the case of water, the oxygen atom end sup with a slight negative charge because it pulls the shared electrons with Hydrogen closer to itself. This results in the hydrogen atoms having a slightly positive charge do to the imbalance. Which of the following causes bone matrix synthesis and calcification? Osteoclasts Hydroxyapatite Osteoblasts Osteoporosis ---------- Correct Answer ---------- Answer: Osteoblasts
- Osteoblasts are the cells responsible for bone matrix synthesis and calcification
- Osteoclasts remove the calcified bone matrix during bone growth and remodeling.
- Hydroxyapatite is the crystal mineral formed during bone calcification to which collagen and proteoglycans will later be embedded.
- Osteoporosis is an imbalance in bone remodeling, where bone resorption exceeds bone formation, resulting in porous and fragile bones. Which of the following is the process by which gametes divide and produce half the number of chromosomes found in a somatic cell?
Gametes Meiosis Fertilization Zygote ---------- Correct Answer ---------- Answer: Meiosis
- Meiosis is the process by which gametes divide and produce half the number of chromosomes found in a somatic cell (a body cell). During meiosis, the cells divide twice instead of once. This results in the daughter cells (the gametes) having half of the chromosomes you would find in a somatic cell, which only undergoes one division during mitosis. The second division is necessary for gametes, since when an egg is fertilized, the chromosomes from each gamete are combined to form a zygote.
- Gametes are the male and female sex cell which contain half set of chromosomes.
- Fertilization is the process of union of male and female gametes which result to a fertilized egg, or zygote, which contains a full set of chromosomes. Which of the following is happening during a contraction of the diaphragm? A decrease in the volume of the thoracic cavity An increase in alveolar pressure Forced expiration A decrease in alveolar pressure ---------- Correct Answer ---------- Answer: A decrease in alveolar pressure
- When the diaphragm is contracting, it is moving downward and allowing the lungs to inflate. During inhalation, alveolar pressure is decreased because the expansion of the lungs increases the surface area or number of alveoli available for gas exchange, thus reducing the pressure at the alveoli.
- Since air is being inhaled, the volume of air in the thoracic cavity is increased, not decreased. Alveolar pressure increases during exhalation, because the lungs are slightly collapsing, reducing the surface area of the alveoli.
- Forced expiration is not occurring during diaphragm contraction, because this indicates inhalation. The term _________________ refers to the contraction of smooth muscle in the digestive system that moves food along the GI tract. retroperistalsis segmentation vasoconstriction peristalsis ---------- Correct Answer ---------- Answer: peristalsis
- Peristalsis is the contraction of smooth muscle that lines the esophageal walls. The smooth muscle has a circular layer as well as a longitudinal layer of muscle that allows a "wringing" action of the smooth muscle to push food down the esophagus.
- Vasoconstriction refers to the constriction of blood vessels and is not directly related to digestive function.
- Segmentation is the muscular contraction of the smooth muscle layers of the stomach that moves food around to ensure its interaction with digestive juices.
- Retroperistalsis is the countermovement to peristalsis where the smooth muscle contracts pushing esophageal contents back towards the mouth. This usually occurs just prior to vomiting. Movement of molecules in a substance depends on _______ energy. Gamma ray heat X-ray UV ---------- Correct Answer ---------- Answer: heat
- All matter is made of particles called atoms (which make up molecules). These atoms and molecules are always in motion - bumping into each other or vibrating back and forth. Heat is a form of energy that is created through the movement of atoms and molecules.
- The amount of movement of molecules in a substance increases as it gains heat and decreases as it loses heat. At higher temperatures, particles have more energy. Some of this energy can be transmitted to other particles that are at a lower temperature.
- There are many types of electromagnetic waves. From lowest energy to highest energy there are radio waves, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays (see diagram below). They do not affect the movement of particles in substances. ______ is an inflammatory conditions of the joints brought on by the gradual wear-and- tear of cartilage that lines the articular ends of bones. Osteoporosis Osteoarthritis Brittle Bone Disease Rheumatoid arthritis ---------- Correct Answer ---------- Answer: Osteoarthritis
- Osteoarthritis is the inflammatory condition of joints due to the wear-and-tear of cartilage that lines the articular ends of bones.
- Osteoporosis is an imbalance in bone remodeling where bone resorption exceeds bone formation, resulting in porous and fragile bones.
- Brittle Bone Disease is a congenital disorder of defective or deficient collagen synthesis due to genetic mutations.
- Rheumatoid arthritis is a chronic inflammation of joints due to autoimmune destruction of articular cartilage. Which of the following is a carbohydrate? ATP Cellulose Collagen Myosin ---------- Correct Answer ---------- Answer: Cellulose
- Cellulose is a polysaccharide (a sugar) that is made up of a linear chain of several hundred to many thousands of β linked D-glucose molecules. Carbohydrates are built from simple sugars.
- Adenosine triphosphate (ATP) is a complex organic chemical that provides energy to drive many processes in living cells, (e.g. muscle contraction, nerve impulse propagation, and chemical synthesis).
- Collagen is the main structural protein in the extracellular space in the various connective tissues in the body.
- Myosins are a family of motor proteins that play roles in muscle contraction as well as a range of other motility processes in eukaryotic organisms. Which of these nitrogenous bases are found in DNA? Adenosine, genotropin, thymine, crystalline Cytosine, adenine, guanine, thymine Thymine, cytosine, adenine, uracil Uracil, adenosine, thiamine, cytosine ---------- Correct Answer ---------- Answer: Cytosine, adenine, guanine, thymine
- Nitrogenous bases are nitrogen-containing biological compounds that form nucleosides, which are components of nucleotides. The two-carbon nitrogen ring bases (adenine and guanine) are purines, while the one-carbon nitrogen ring bases (thymine and cytosine) are pyrimidines.
- DNA is composed of cytosine, adenine, guanine, and thymine.
- RNA is composed of cytosine, adenine, guanine, and uracil.
Which of the following structures is correctly paired with its description? Urethra/ temporarily store the sperm Prostate gland/ secretion of fluid that contributes to sperm motility and viability Seminal vesicle/ transports sperm from epididymis to urethra Vas deferens/ transports urine in both male and female and semen in male ---------- Correct Answer ---------- Answer: Prostate gland/ secretion of fluid that contributes to sperm motility and viability
- The prostate gland secretes fluid that contributes to sperm motility and viability.
- The seminal vesicle secretes an alkaline, viscous fluid that contains fructose, prostaglandins, and clotting proteins.
- The Vas deferens transports sperm from the epididymis to the urethra. The urethra then transports both urine and semen (in males). Which of the following is responsible for destroying various unhealthy host cells, including those infected with a virus or bacteria? T-cells Natural killer cells B-cells Dendritic cells ---------- Correct Answer ---------- Answer: Natural killer cells
- Natural killer cells are responsible for destroying various unhealthy host cells, including those infected with virus or bacteria.
- Dendritic cells are responsible for initiating immune responses by presenting antigens to T-cells.
- T-cells and B-cells are cells of the adaptive immune system that directly attack antigens and produce antibodies, respectively Which of the following describes cellular respiration? It is a reductive catabolic activity It is an oxidative anabolic activity It is an oxidative catabolic activity It is a reductive anabolic activity ---------- Correct Answer ---------- Answer: It is an oxidative catabolic activity
- An anabolic reaction is a reaction that uses energy to build molecules the organism needs. A catabolic reaction breaks down complex molecules into smaller molecules to create energy for the organism to use.
- Oxidation is when an element loses one or more electrons to oxygen. Reduction is when an element gains one or more electrons.
- Cellular respiration is the process in which a cell takes in oxygen and uses it to break down glucose to create energy in the form of ATP. In the final stage of cellular respiration (called the electron transport chain), oxygen accepts electrons and picks up protons to form water. So, because elements lose electrons to oxygen and it is a reaction in which energy is created, cellular respiration is both an oxidative and catabolic activity. The renin-angiotensin-aldosterone system (RAAS) is essential in regulating blood pressure. Which of the following hormones involved in RAAS is produced by the kidney? Angiotensin I Angiotensin II Renin Aldosterone ---------- Correct Answer ---------- Answer: Renin
- Renin is produced by the kidney in response to changes in blood pressure.
- Angiotensin is produced upon the cleaving of angiotensinogen
- Aldosterone is produced by the adrenal cortex. Which of the following is a substance that the kidneys remove from the blood during filtration? Carbon Dioxide Salts Oxygen Red Blood Cells ---------- Correct Answer ---------- Answer: Salts The kidneys filter waste from the blood, including salts. They do not filter gases out of the blood, nor do they filter out cells. Why are control groups used in experiments? To help scientists quickly perform experiments To minimize the effect of variables To ensure the accuracy of measurements To increase the amount of data collected ---------- Correct Answer ---------- Answer: To minimize the effect of variables
A control group is used to ensure that the number of variables that influences a data set is minimized. This is done by comparing measured data to the control group, which has many fixed variables. Ba(NO3)2 + Na2SO4 → BaSO4 + 2 NaNO Single replacement reaction Decomposition Double replacement Acid-base reaction ---------- Correct Answer ---------- Answer: Double replacement
- In a double replacement reaction, two metal ions (Ba²+ and Na+) switch places with each other in two ionic compounds.
- A similar reaction is the single replacement reaction, where two metal ions are swapped in only a single ionic compound.
- In a decomposition reaction, a single compound is broken down into several other smaller compounds.
- In an acid-base reaction, a proton (H+) is transferred from one molecule to another, which has not occurred in the reaction above. Which of the following enzymes is responsible for breaking down a polysaccharide to a disaccharide? Amylase Cobalamin Catalase Trypsin ---------- Correct Answer ---------- Answer: Amylase
- Amylase is an enzyme that is secreted by the salivary glands and the pancreas to break down starch to maltose, which is a disaccharide.
- Trypsin is found in the digestive system of many vertebrates, where it hydrolyzes proteins.
- Cobalamin is a water-soluble vitamin that plays a role in DNA synthesis, and is involved in both fatty acid and amino acid metabolism.
- Catalase catalyzes the decomposition of hydrogen peroxide to water and oxygen. During contraction, thin ________________ filaments slide past the thick ______________ filaments which result to shortening of sarcomere and contraction of the muscle.
actin/ tropomyosin actin/ myosin troponin/ tropomyosin myosin/ troponin ---------- Correct Answer ---------- Answer: actin/ myosin The sarcomere is made up of thin filament (actin) and thick filament (myosin) which slide past each other during contraction. Troponin and tropomyosin are both regulatory proteins that regulate contraction and relaxation of skeletal muscle. Which of the following hormones is responsible for increasing calcium levels in the blood by stimulating bone resorption? Luteinizing hormone Thyroid hormone Parathyroid hormone Insulin ---------- Correct Answer ---------- Answer: Parathyroid hormone
- The Parathyroid hormone is responsible for increasing calcium levels in the blood by stimulating bone resorption. Bone resorption is the process by which osteoclasts break down the tissue in bones and release the minerals, resulting in a transfer of calcium from bone tissue to the blood.
- The Thyroid hormone (T3 and T4) regulate basal metabolism.
- The Luteinizing hormone stimulates ovulation and production of testosterone.
- Insulin decreases the level of glucose in the blood by stimulating cellular uptake. Which of the following does not describe the dermis? The thickest layer of the skin The layer of the skin where cells containing the pigment melanin are found The layer of the skin that contains the network of capillaries necessary for thermoregulation A vascular layer of the skin ---------- Correct Answer ---------- Answer: The layer of the skin where cells containing the pigment melanin are found
- The dermis is the thickest layer of the skin. It is highly vascular (has many blood vessels), as it has to supply oxygen and nutrients to the epidermis, which is avascular (lacking blood vessels). The dermis also contains the network of capillaries necessary for thermoregulation.
- The layer of the skin where cells containing the pigment melanin are found is the epidermis.
Which of the following would be the best choice to measure 0.0015 grams of a chemical reagent? Metric ruler Triple beam balance Analytical balance Graduated cylinder ---------- Correct Answer ---------- Answer: Analytical balance
- Analytical balances are the most common way to measure the mass of substances in a chemical laboratory. They are useful for measuring sub-milligram (0.001 g) masses.
- A triple-beam balance is not as accurate as an analytical balance and is only capable of measuring masses with an error of 0.05 g.
- A graduated cylinder is used to measure the volume of liquids, which is measured in mL, not in grams.
- A metric ruler is used to measure the length of objects, which is measured in units derived from the meter. ________ is the mechanism of glandular secretion in which stimulation results in continuous production of a hormone above the normal level. Positive feedback Negative feedback Homeostasis Thermoregulation ---------- Correct Answer ---------- Answer: Positive feedback
- In a positive feedback mechanism, glandular secretions are stimulated to continuously produce a hormone until another control mechanism shuts it off.
- In a negative feedback system, once the normal level of product is attained, production slows down and stops. A guinea pig with short orange fur is crossed with a guinea pig with long orange fur. The offspring are also crossed, and the F2 generation contains 17 guinea pigs with long orange fur, 2 guinea pigs with short beige fur, 6 with short orange fur, and 7 with long beige fur. Which of the following phenotypes are dominant? Short and beige are dominant. Dominance cannot be determined. Long and beige are dominant. Long and orange are dominant. ---------- Correct Answer ---------- Answer: Long and orange are dominant.
- According to Mendel's law of independent assortment, alleles of two different genes get sorted into gametes (sex cells) independently of one another. Therefore, the allele one gamete receives for a gene does not influence the allele received for another gene.
- In this example, we see a cross between two dihybrids. A dihybrid is an organism that is heterozygous for two genes. This means that the organism has two different alleles for each gene (e.g. AaBb). A cross between two dihybrids is known as a dihybrid cross.
- When Mendel did a dihybrid cross with his pea plants, he found that there were four different categories of pea seeds in the offspring: yellow and round, yellow and wrinkled, green and round, and green and wrinkled. These categories, which were defined by observable traits (phenotypes) appeared in a ratio of approximately 9:3:3:1.
- We can use this approximate ratio to determine which of the phenotypes are dominant.
- If we mark fur color with the gene Y and y (for the recessive allele) and fur length with R and r (for the recessive allele), the genotypes that would be produced are approximately in the ratio of 9:3:3:1 (if you divide the total offspring by 2, you get approximately the same numbers as Mendel). *Note: When a genotype is written as Y_ it is to indicate that it could be either YY or Yy. This can be used when discussing phenotypes since the dominant allele will be the one that is expressed.
- 17 long orange (Y_R_): 6 short orange (Y_rr): 7 long beige (yyR_): 2 short beige (yyrr) = approximately 9:3:3:
- This leads us to the understanding that long and orange fur is dominant. Physiologically, bone resorption and deposition are in equilibrium. Which of the following is the result of inhibition of bone resorption and prevention of calcium removal from the bone? Kyphosis Achondroplastic dwarfism Muscle atrophy Hypocalcemia ---------- Correct Answer ---------- Answer: Hypocalcemia
- Inhibition of bone resorption and the prevention of calcium removal from the bone will result in low levels of calcium (hypocalcemia) and can lead to tetany.
- Muscle atrophy is the wasting away of muscle due to poor mobility or other underlying conditions.
- Achondroplastic dwarfism is abnormal bone development brought by a defect in endochondral ossification.
- Kyphosis is an abnormal curvature of the vertebral column due to poor stature or weakening of the bone. Blood vessels that supply nutrients and oxygen enter the bone tissues through the __________. Osteons Lacunae Lamellae Volkmann canals ---------- Correct Answer ---------- Answer: Volkmann canals
- Volkmann canals are channels in the bone that transmit blood vessels.
- Osteons are the structural unit of compact bone characterized by concentric bone layers surrounding a central canal.
- Lamellae are concentric rings of hard, calcified extracellular matrix in compact bones.
- Lacunae are small spaces containing osteocytes found between concentric lamellae. Which of the following is the basic contractile unit of the skeletal muscle? Z-disc Sarcomere Sarcoplasmic Reticulum Sarcolemma ---------- Correct Answer ---------- Answer: Sarcomere
- The sarcomere is the basic contractile unit of the skeletal muscle made of thin and thick filaments.
- The sarcolemma is the cell membrane of the muscle fiber while sarcoplasmic reticulum is the smooth endoplasmic reticulum that stores calcium for muscle contraction.
- The Z-disc is the boundary of each sarcomere. Which of the following is the result of demyelination? Disrupted propagation of action potential along the axon Uptake of neurotransmitters will be inhibited Defective transport of organelles and macromolecules from cell body to axon Neurotransmitters will not be produced ---------- Correct Answer ---------- Answer: Disrupted propagation of action potential along the axon The myelin sheath is primarily important in the efficient and fast transmission of nerve impulses along the axon of a neurons. Demyelination happens as a result of a disease of the nervous system in which the myelin sheath of neurons is damaged. When
demyelination occurs, the propagation of action potential along the axon will be disrupted and defective. Which of the following substances is synthesized in the skin from a cholesterol-based precursor upon safe exposure to ultraviolet (UV) rays of sunlight? Keratin Sweat Melanin Vitamin D ---------- Correct Answer ---------- Answer: Vitamin D
- Vitamin D is synthesized in the skin from a cholesterol-based precursor upon safe exposure to ultraviolet (UV) rays of sunlight.
- Keratin is synthesized by cells in the epidermis called keratinocytes.
- The pigment melanin, which is responsible for the color of skin, is synthesized by cells in the epidermis called melanocytes.
- Sweat is produced by the eccrine glands in order to facilitate evaporative cooling. Which of the following statements is true about hydrogen bonds? They don't affect the properties of water in any way They form between a partial positively charged region on one molecule and the partial negatively charged region on another molecule They are considered strong attractive forces They result from the attraction between ions that have no charge ---------- Correct Answer ---------- Answer: They form between a partial positively charged region on one molecule and the partial negatively charged region on another molecule
- Hydrogen bonding occurs between molecules when at least one contains a hydrogen atom and both molecules have a small electric charge because the molecule is polar. Polar molecules, such as water, result from one atom having a stronger pull on the shared electrons, which causes the atoms to have slight negative or positive charges. The slight positive charge of the hydrogen atoms allow them to form hydrogen bonds with the atoms in other polar molecules with slightly negative charges.
- Although hydrogen bonds are considered a weak attractive force, they are the strongest weak bonds (also known as "Vander Waal's forces") by far. As a result, hydrogen bonding is weaker than both ionic and covalent bonds.
- Water is strongly affected by hydrogen bonding. Because the hydrogen bonds attract water molecules to one another, water is more tightly packed in liquid form than in solid form, where the molecules are held further apart in a lattice.
Which would be the approximate mass of a car? 180 kg 180,000 kg 1,800 kg 18 kg ---------- Correct Answer ---------- Answer: 1,800 kg It's good to have a relative idea of the scale of various objects. The average mass of a human is around 60 kg. The average mass of a car is 1,800 kg, and the average mass of a laptop is 2.5 kg. In order to break apart a polysaccharide into disaccharides, what type of reaction needs to occur? Condensation Hydrolysis Oxidation-reduction Glycosidic ---------- Correct Answer ---------- Answer: Hydrolysis
- Hydrolysis reactions add water to break glycosidic bonds between the monomers in a polysaccharide.
- Disaccharides are formed by the condensation reactions of two simple sugar molecules coming together. Two OH groups, one from each sugar molecule, come together and form an oxygen bridge between.
- There is no such thing as a "glycosidic reaction" but rather a glycosidic bond forms by a condensation reaction, which means that one water molecule is produced during formation of a glycosid.
- An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between two species. When DNA is being transcribed, it is read in codons. How many bases does each codon contain? 5 4 3 6 ---------- Correct Answer ---------- Answer: 3
- A codon is a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis.
- This can sometimes be confused with the number of nucleotides. There are 4 nucleotides that make up the sequence of DNA, but they are grouped in 3's for transcription. Which of the following statements correctly describes what genes code for: 1 - More DNA 2 - Lipids and carbohydrates 3 - Proteins and RNA 4 - Proteins and lipids ---------- Correct Answer ---------- Answer: Statement 3
- The portion of the genome that codes for a protein or an RNA is referred to as a gene.
- Lipids and carbohydrates are created in the cell by enzymes, using raw materials from outside. Which of the following comparisons between arteries and veins is true? Veins have a smaller diameter than arteries. Veins carry freshly oxygenated blood from tissue back to the heart, while arteries carry oxygen-depleted blood away from the heart. Veins have thick, muscular walls, while arteries have thin, more compliant walls. Veins have valves, and arteries do not. ---------- Correct Answer ---------- Answer: Veins have valves, and arteries do not.
- Due to the lower pressure in the venous system and the fact that most blood is trying to return back to the heart against the force of gravity, veins have valves that prevent blood from moving backwards.
- Veins do not contain thick, muscular walls like arteries do. If venous walls were thick like arterial walls, there would be more resistance for blood flowing into veins. Since blood in the venous side is already under a lower pressure, this would create a problem for blood to return to the heart. Arteries have thick muscular walls due to the higher pressure of blood flow in the arterial side of circulation.
- Veins carry blood that is leaving tissue after it has unloaded oxygen, therefore they carry oxygen-depleted blood, along with metabolic waste back towards the heart. Venous blood carries oxygen-deficient blood back to the heart. Arteries carry oxygen- rich blood from the heart to tissues where oxygen can be delivered and used for cellular respiration.
- Due to the higher pressure in which arterial blood must flow, arteries have thicker walls and smaller lumen, or diameter, as compared to veins. Veins are often considered to be capacitance vessels as they carry a larger volume of blood, and have thinner walls, and greater wall compliance to accommodate the higher volume of blood.
Atomic mass does not include ________ in its calculation. The atomic number of an element is the number of ___________. electrons; neutrons protons; neutrons neutrons; protons electrons; protons ---------- Correct Answer ---------- Answer: electrons; protons
- The atomic mass of an element is the average sum of the protons and neutrons in a group of those atoms. However, electrons are so much smaller (have so much less mass) than protons and neutrons that they don't factor into the calculation. So, the atomic mass is the sum of the masses of protons and neutrons.
- The number of protons in the nucleus is the defining property of an element, and is referred to as the atomic number. Filtration of blood occurs in the renal corpuscles. Which of the following is not part of the renal corpuscles? Glomerular Basement Membrane Bowman's capsule Vasa Recta Glomerulus ---------- Correct Answer ---------- Answer: Vasa Recta
- A renal corpuscle is made up of the loop of capillary networks called the glomerulus, and the blind end of the nephron which is called the bowman's capsule. The combined basement membrane of these two structures makes up the glomerular basement membrane.
- The Vasa recta, on the other hand, is a capillary loop in the renal medulla, running parallel to the loop of Henle. Which of the following definitions is correct? Liquids have a constant volume but not a constant shape. Gases have a constant volume and constant shape. Solids lack a constant volume but have a constant shape. Solids have neither a constant volume nor a constant shape. ---------- Correct Answer --- ------- Answer: Liquids have a constant volume but not a constant shape.
- Liquids can occupy whatever shape their container has, so they do not have a fixed shape. Because the particles in liquids are very close together (barely further apart than in solids) liquids do not easily compress, so their volume is fixed.
- A gas is a substance with no definite volume and no definite shape. Solids and liquids have volumes that do not change easily.