ATI TEAS VI - SCIENCE

Steps involved in natural selection include: 1. Differing survival rates when faced with environmental challenges.; 2. Preservation of genetic traits of best-adapted offspring; 3. Overproduction of offspring that have different variations in genetic traits Which of the following is the sequence in which these steps take place? 3, 2, 1 2, 1, 3 1, 2, 3 1, 3, 2

Answer: 1, 3, 2 -Natural selection is the process by which organisms that are better suited to their environment are able to survive and produce more offspring. As a result of natural selection, the proportion of organisms within a species that have favorable adaptations to a given environment will increase with each generation. -Organisms (within populations) have differences in appearance and behavior on an individual basis. These differences, or variations, can include characteristics such as body shape or size, skin or hair color, physical markings or structures, or behaviors such as methods of obtaining food. -Organisms, within a species, that possess physical and behavioral traits that allow them to be more successful in obtaining resources will be more likely to survive and reproduce. -When organisms are faced with environmental changes, we often see a shift in what is considered a "favorable" trait within the species. This then has an effect on the overall population of organisms in terms of their physical and behavioral characteristics. -These "best adapted" traits will be passed onto the next generations given that individuals with these traits will be more likely to survive and continue reproducing.

Which would be the approximate mass of a car? 180 kg 180,000 kg 1,800 kg 18 kg

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.

Which of the following statements is true? A double-blind experiment controls all variables. A double-blind experiment is always more accurate than a single-blind experiment. A single-blind experiment helps reduce researcher bias. A single-blind experiment eliminates all unknown variables.

Answer: A double-blind experiment is always more accurate than a single-blind experiment. A double-blind experiment is an experiment where both the researcher and subject are unaware of the treatment that a test subject receives. This is different from a single-blind experiment, where only the subject is unaware. While it is true that a double-blind experiment is used to reduce researcher bias, this does not necessarily equate to more accurate results. This is because there can be other unaccounted variables that influence the results, called lurking variables.

Which of the following components of renin-angiotensin-aldosterone system (RAAS) is not correctly paired with its function? Angiotensin converting enzyme (ACE) - activation of angiotensin I to angiotensin II Angiotensin II - vasoconstriction and elevation of blood pressure Renin - cleavage of angiotensinogen to angiotensin I Aldosterone - sodium and water reabsorption

Answer: Aldosterone - sodium and water reabsorption Upon stimulation, the kidney secretes renin which cleaves the circulating angiotensinogen to angiotensin I. Angiotensin I is then activated by ACE to Angiotensin II, which stimulates vasoconstriction (constriction of blood vessels) and an increase in blood pressure. Angiotensin II also stimulates the adrenal cortex to produce aldosterone, which influences the kidney to reabsorb salt. Water reabsorption is primarily under the influence of ADH (antidiuretic hormone) or vasopressin.

Which of the following glands is correctly paired with its secretion? Ceruminous glands/ oil that moisturizes hair and skin Apocrine sweat glands/ secretion that, when released, has an odor with a possible pheromone function in humans Sebaceous glands/ production of sweat necessary for evaporative cooling Eccrine glands/ sticky barrier that prevents foreign bodies and insects from entering the ears

Answer: Apocrine sweat glands/ secretion that, when released, has an odor with a possible pheromone function in humans -Ceruminous glands function in producing a sticky barrier that prevents foreign bodies and insects from entering the ears. -Sebaceous glands produce oil that moisturizes the hair and skin. -Eccrine glands produce sweat necessary for evaporative cooling.

The same single-replacement reaction is run in two different beakers. The beakers are labeled as Beaker A and B and are heated to 75oC and 100oC, respectively. If the reactions are run for 15 minutes each, which of the following results would you expect to observe? The two beakers produce the same amount of product No products are produced in either beaker Beaker A produces more product than Beaker B Beaker B produces more product than Beaker A

Answer: Beaker B produces more product than Beaker A As the temperature of a reaction increases, the reaction rate increases as well. This is due to an increased number of collisions that occur between molecules during a reaction. Since Beaker B is at a higher temperature, it should produce more product than Beaker A since the reaction times are equal.

Fragile bones due to production of deficient or defective collagen as a result of a genetic defect is a characteristic of which of the following conditions? Osteoporosis Kyphosis Brittle Bone Disease Tetany

Answer: Brittle Bone Disease -Brittle Bone Disease is a congenital disorder that involves defective or deficient collagen synthesis due to genetic mutations. -Osteoporosis is an imbalance in bone remodeling wherein bone resorption exceeds bone formation resulting to porous and fragile bones. -Tetany is characterized by spastic muscle contractions due to calcium deficiency.

The functional unit of the kidney is the nephron. A nephron is made up of renal tubules and renal corpuscles, both of which perform different functions. Which of the following parts of the nephron is not correctly paired with its function? Loop of Henle - Reabsorption of water Glomerulus - Filtration of blood Collecting Ducts - Secretion of water Proximal Convoluted Tubules - Reabsorption of ions and solutes

Answer: Collecting Ducts - Secretion of water The Collecting Duct is the final site of water reabsorption, so no water would be secreted from this structure.

Which of the following describes what would happen during a period of hyperventilation? Decreased carbon dioxide levels result in an increase in pH Decreased carbon dioxide levels result in a decrease in pH Increased carbon dioxide levels result in an increase in pH Increased oxygen uptake results in greater tissue perfusion

Answer: Decreased carbon dioxide levels result in an increase in pH Hyperventilation is the increase in breathing rate beyond the normal rate. When this happens, more carbon dioxide than needed is exhaled lowering the carbon dioxide levels in the blood. As a compensatory mechanism to increase carbon dioxide levels, hydrogen ions are used, creating more bicarbonate as a byproduct and increasing the pH.

______________ is the exchange of oxygen and carbon dioxide across the alveolar membrane. Osmosis Diffusion Active transport Exocytosis

Answer: Diffusion -Diffusion is the passive movement of a substance from high concentration to low concentration. During inhalation, oxygen in the alveoli has to make its way into the blood, and this occurs via diffusion. A high oxygen concentration in the alveoli drives the movement of oxygen into the pulmonary capillaries where oxygen content is low. Conversely, carbon dioxide is also exchanged this way, but is unloaded, or moved from the blood to the alveoli for exhalation. -Osmosis is a type of diffusion, however it involves the movement of water across a membrane. This happens when particles or substances are not able to pass through a membrane. This is not what happens at the alveoli, as the movement of gas molecules is necessary. -Exocytosis is a type of vesicular transport which involves the release of a substance from inside a cell to outside a cell as the vesicle is dissolved. -Active transport is a type of membrane transport that requires ATP, usually because a substance needs to move against its concentration gradient, rather than along with the gradient.

The number of ________ is the same across a period but increases when moving down a group anions cations isotopes electron shells

Answer: Electron shells As you move from left to right across the periodic table (period), the atomic number increases. As you move from top to bottom (group), the number of filled electron shells increases.

Which of the following antigen-specific immune cells produce cytokines, which facilitate various immune reactions? Macrophage cell Cytotoxic T-cell B-cell Helper T-cell

Answer: Helper T-cell -Helper T-cells produce cytokines, which facilitate the actions of B-cells and Cytotoxic T-cell. -B-cells are responsible for producing immunoglobulins or antibodies while cytotoxic cells directly attack and destroy pathogens. -Helper T-cells, cytotoxic cells and B-cells are all antigen-specific immune cells. -Macrophage cells are part of non-specific innate immune system which engulf and destroy bacteria and cellular debris during infection and injury.

Which of the following does not correctly describe a cell membrane? It is composed entirely of proteins and lipids. It is composed of a single layer of lipids interspersed with proteins. Fat soluble substances such as oxygen, carbon dioxide, and alcohol can easily pass through the membrane. The phospholipid component has hydrophilic heads and hydrophobic tails.

Answer: It is composed of a single layer of lipids interspersed with proteins. The cell membrane is a lipid bilayer primarily made up of lipids and proteins. The phospholipid component has hydrophilic heads and hydrophobic ends. The hydrophobic ends make up the middle portion of the membrane and this layer makes it easy for fat soluble substances, such as oxygen, carbon dioxide, and alcohol to pass through.

When going to the grocery store, you need to purchase some vegetables, which are sold by weight. Which of the following units would the weight of the vegetables be expressed in? Coulombs Kilograms Newtons Pascals

Answer: Kilograms -A kilogram is the SI unit of mass. Since vegetables are sold by weight, this would be the most appropriate unit of measurement. -Newtons are used to measure forces -Coulombs measure electrical charges -Pascals measure pressure.

Which of these is not a function of mitosis? Repair of damaged tissue Growth of the organism Producing gametes Asexual reproduction

Answer: Producing gametes -Mitosis plays an important part in the life cycle of most living things, though to varying extents. In unicellular organisms such as bacteria, mitosis is a type of asexual reproduction, making identical copies of a single cell called daughter cells. In multicellular organisms, mitosis produces more cells for growth and repair. -Meiosis produces haploid gametes (ova or sperm) that contain one set of 23 chromosomes because they divide twice during the process.

Which of the following involves positive feedback? An elevated level of T3 inhibits release of TSH (thyroid-stimulating hormone) Stimulation of stretching of the cervix and uterine contractions by oxytocin Secretion of insulin and glucagon in response to the level of blood glucose Control of calcium levels in the blood by parathyroid hormone

Answer: Stimulation of stretching of the cervix and uterine contractions by oxytocin -During childbirth, oxytocin stimulates cervical stretching and uterine contraction, which in turn stimulate the production of more oxytocin to facilitate delivery. -The maintenance of levels of thyroid hormones, calcium and glucose in blood all works through negative feedback loops wherein increased levels of product in the blood inhibits further stimulation.

Which of the following components can be found in a phase graph? Pressure and time as its axes Temperature and pressure as its axes A "critical point"where the substance is indistinguishable between solid and gaseous states A "triple point" where three slightly different types of solid coexist

Answer: Temperature and pressure as its axes The phase diagram is a graphical representation of the physical states of a substance under varying conditions of temperature and pressure. A typical phase diagram has pressure on the y-axis and temperature on the x-axis. They contain a triple point - the point on a phase diagram at which the three states of matter: gas, liquid, and solid coexist; and a critical point - the point on a phase diagram at which you cannot tell the difference between the liquid and gaseous states of the substance.

Activation of B and T lymphocytes and production of memory lymphocytes are specific cellular responses by which of the following? The internal aspect of the innate immune system Passive immunity Antibody-mediated immunity The internal aspect of the adaptive immune system

Answer: The internal aspect of the adaptive immune system -The activation of B and T lymphocytes and production of memory lymphocytes are specific cellular responses of the adaptive immune system. -The internal aspect of the innate immune system involves non-specific cellular responses which include inflammation, production of interferons and phagocytosis. -Passive immunity occurs when a person is given antibodies rather than eliciting personal production. -Antibody-mediated immunity involves production of specific proteins called antibodies which inactivate the antigen.

The site where two or more bones meet is called a __________________. cartilage tendon ligament joint

Answer: joint -The site where two or more bones meet is called joint. -A tendon is a fibrous tissue that attaches muscle to a bone. -A ligament is also a fibrous tissue that connects bones, cartilage and joints. -Cartilage is a tough connective tissue that supports the bone and facilitates movement.

Which part of the phospholipids are called the "head"? the phosphate group and the glycerol molecule the phosphate group the fatty acid chains the fatty acid chains and the phosphate group

Answer: the phosphate group and the glycerol molecule The phosphate group and glycerol molecule are called the "head" of the phospholipid and the fatty acid chains are called the "tails." Both phospholipids and triglycerides contain a glycerol molecule joined with ester bonds.

Which of the following would an electron microscope be used to measure? The strength of chemical bonds 20-nm polymer films Insect samples Aquatic samples

Answer: 20-nm polymer films Electron microscopes are powerful tools for obtaining images of incredibly small objects that cannot be observed by regular optical microscopes. Electron microscopes are capable of imaging samples that are only several nanometers in size, such as thin polymer films. Biologists sometimes examine insects, but they generally do this with optical microscopes since the insects are so large. Aquatic samples cannot be used in an electron microscope because the technique is performed in a vacuum.

When DNA is being transcribed, it is read in codons. How many bases does each codon contain? 5 4 3 6

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 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

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.

An atom has 5 protons, 2 neutrons, and 5 electrons. Which of the following is the atom's mass number? 7 12 5 10

Answer: 7 To calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons. In this case, you should add 5 and 2, which equals to 7. Electrons are so small, they are not factored into the atomic mass.

Which of the following statements is true about monohybrid F1 crosses in Mendelian inheritance? A cross is made between two heterozygous individuals. A cross is made between two homozygous individuals. All of the offspring express the recessive trait. All of the offspring have lethal genes.

Answer: A cross is made between two heterozygous individuals. -The monohybrid cross is used to determine which of the two alleles of a gene is dominant. The cross begins with the parental generation. One parent is homozygous for one allele (which means it has two of the same allele such as FF or ff), and the other parent is homozygous for the other allele (which means it has one of each allele, such as Ff). The offspring make up the first filial (F1) generation and all individuals are heterozygous (Ff). A cross between two F1 individuals will always mean a cross between two heterozygous individuals. -The offspring of such a cross (Ff x Ff) will result in 75% of offspring expressing the dominant trait (FF and 2xFf) and 25% of the individuals expressing the recessive trait (ff).

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

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.

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

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 describes the role of acetylcholine in muscle contraction? Acetylcholine binds to the sarcolemma to open calcium channels. Acetylcholine binds to the membrane receptor and inhibits the stimulation and contraction of muscle fiber. Binding of acetylcholine results in the repolarization of the sarcolemma. Acetylcholine binds to the membrane receptor in the sarcolemma and facilitates opening of the sodium channels.

Answer: Acetylcholine binds to the membrane receptor in the sarcolemma and facilitates opening of the sodium channels. Stimulation of the motor neuron results in the release of the neurotransmitter acetylcholine (Ach) to the synapse, or neuromuscular junction. Ach then binds to the membrane receptor and opens sodium channels which results in the depolarization of the sarcolemma. Depolarization of the sarcolemma opens calcium channels which facilitates the contraction of the muscle fiber.

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.

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.

________ is not normally found in urine, and its presence may indicate a problem with the kidneys. Ammonium Bilirubin Albumin Urea

Answer: Albumin -Albumin is a plasma protein that is not normally present in the urine under normal conditions. -Urea, ammonium, and drug metabolites are metabolic wastes commonly present in the urine. Bilirubin is also a waste product that is normally present in the urine, but at low levels. (High levels of bilirubin indicate disease conditions.)

Which of the following enzymes is responsible for breaking down a polysaccharide to a disaccharide? Amylase Cobalamin Catalase Trypsin

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.

Which of the following statements is true? An orbital is a space around the nucleus of an atom where a proton is likely to be found. Valence electrons reside in the innermost shell of an atom. An orbital is a space around the nucleus of an atom where an electron is likely to be found. The number of orbitals that an atom has is the same for all elements.

Answer: An orbital is a space around the nucleus of an atom where an electron is likely to be found. -Atomic orbitals are regions of space around the nucleus of an atom where an electron is likely to be found. Atomic orbitals allow atoms to form covalent bonds. -A valence electron is a single electron (or one of two or more electrons) in the outer shell of an atom that is responsible for the chemical properties of the atom. -Since different elements have different electron numbers in their atoms, they each have a different number of orbitals for the electrons to reside in.

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

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.

Which of the following is/are responsible for producing antibodies? Helper T-cells Cytotoxic T-cells B-cells Histamine

Answer: B-cells -B-cells are responsible for producing antibodies that bind and inactivate antigens. -Cytotoxic T-cells are immune cells responsible for destroying pathogens -Helper T-cells produce cytokines -Histamine is produced by mast cells in response to infection and injury.

Dopamine is one of the neurotransmitters in the nervous system. What happens when dopamine is released into the nerve synapse? Dopamine will enter the cytoplasm of the postsynaptic cell Firing of an action potential by the presynaptic cell Excitation and contraction of the presynaptic cell Binding of dopamine to the membrane receptor of the postsynaptic cell

Answer: Binding of dopamine to the membrane receptor of the postsynaptic cell In response to a nerve stimulus, the presynaptic cell releases dopamine which diffuses to the synaptic cleft and binds to the membrane receptor of the postsynaptic cell. The postsynaptic cell will then convert the chemical stimuli to an electrical signal generating an action potential that will be transmitted to an effector.

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

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.

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

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.

The epiphyseal plate, which is responsible for the growth in the length of a bone, is made of which of the following? Osteons Cartilage Osteoclasts Osteocytes

Answer: Cartilage -The epiphyseal plate which is responsible for continued elongation of bones is made up of cartilage. -Osteoclasts are responsible for resorption of calcified bones during remodeling, while almond-shaped osteocytes are responsible for maintenance of calcified bone matrix. -Osteons are the structural unit of compact bone characterized by concentric bone layers surrounding a central canal.

Which of the following is a carbohydrate? ATP Cellulose Collagen Myosin

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 the following parts of the brain is responsible for posture, balance and movement coordination? Occipital lobe Temporal lobe Cerebellum Cerebrum

Answer: Cerebellum -The cerebellum is the part of the brain responsible for balance and equilibrium. -The cerebrum is responsible for sensory and motor controls, as well as cognitive functions. -The temporal lobe is part of the cerebrum and is responsible for interpretation of hearing impulses -The occipital lobe is part of the cerebrum and is for interpretation of visual impulses.

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

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

Which of the following structures is not correctly matched with its function? Vas deferens/ sperm duct to penis Penis/ external sexual organ of male Cervix/ implantation site of a zygote Vagina/ copulatory organ of female

Answer: Cervix/ implantation site of a zygote -The implantation site of a fertilized egg, or zygote, is the uterus. The cervix is a neck of tissue that connects the vagina to the uterus. -The Vas deferens is the sperm channel from the epididymis to the penis. -The penis is the external sexual organ of male. -The vagina is the copulatory organ of female. The sperm enters the female's body in the vagina and moves through the cervix to reach the uterus, then finally the fallopian tubes.

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

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.

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

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 these nitrogenous bases are found in DNA? Adenosine, genotropin, thymine, crystalline Cytosine, adenine, guanine, thymine Thymine, cytosine, adenine, uracil Uracil, adenosine, thiamine, cytosine

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.

What role does genetic information play in linking a particular sequence of amino acids to produce a protein? DNA is the template from which transfer RNA is built, and the messenger RNA serves as its own bridge between itself and the amino acids. DNA is the template from which messenger RNA is built and transfer RNA acts as bridges between the tRNA and the mRNA. DNA is the template from which more DNA is built and messenger RNA acts as a bridge between the DNA and the transfer RNA. DNA is the template from which messenger RNA is built and transfer RNA molecules act as bridges between the mRNA and amino acids.

Answer: DNA is the template from which messenger RNA is built and transfer RNA molecules act as bridges between the mRNA and amino acids. In DNA, the sequence of the nitrogenuos bases in a gene is used to make an mRNA copy of the DNA (transcription). The mRNA is then "read" by a ribosome (translation) and transfer RNA carries over the appropriate amino acids coded by the mRNA to make a chain of amino acids that then folds into a protein.

When someone is immobile, they may experience loss of bone density due to _________. Tetany Ossification Demineralization Muscle atrophy

Answer: Demineralization -Mechanical stress or physical activity increases bone strength by increasing deposition of minerals and production of collagen. During periods of immobility, the mechanical stress is reduced resulting in demineralization and reduced collagen production. -Poor mobility may also lead to muscle atrophy, which is wasting away of muscles. -Tetany refers to spastic muscle contractions due to calcium deficiency. -Ossification is the process of bone formation.

Which of the following can be classified as an intensive property? Mass Entropy Density Volume

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 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

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.

Ba(NO3)2 + Na2SO4 → BaSO4 + 2 NaNO3 Single replacement reaction Decomposition Double replacement Acid-base reaction

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 statements is false? Double-blind experiments have two control variables. The research subjects in single-blind experiments are unaware of the treatment they receive. Double-blind experiments help eliminate researcher bias. Single-blind experiments help reduce patient bias.

Answer: Double-blind experiments have two control variables. The goal of a double-blind experiment is to reduce or eliminate biases from both the researcher and their subjects. This is done by keeping which treatments patients receive a secret from both the researcher and the subject. Since the patients don't know what type of treatment they received, the researcher can determine if the placebo effect affects their results.

Which of the following conditions would exhibit an increase in lung compliance? Lung cancer Emphysema Bronchitis Asthma

Answer: Emphysema -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. Emphysema increases lung compliance due to the damaged lung tissue. In this condition, the lung will be able to inflate, but the recoil is delayed, thus exhalation is impaired. -Asthma and bronchitis may be associated with some increase in lung compliance however this is less likely with these conditions. These conditions typically demonstrate reduced lung function due to inflammation or airway obstructions as opposed to damaged alveoli. -Lung cancer usually causes a decrease in lung compliance due to the presence of more fibrotic tissue, which makes the long more stiff and harder to inflate.

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

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.

Which of the following terms best describes a sample composed of particles that can be squeezed together? Plasma Liquid Gas Solid

Answer: Gas -The particles in gases are far apart and move about very quickly. The particles have much more energy and this is why they move so fast. The particles collide with each other and the walls of the container filling the volume of the container. A gas can be easily compressed because of the space between the particles. -The particles in a solid are tightly packed and locked in place. Although we cannot see it or feel it, the particles are moving - vibrating in place. -The particles in a liquid are close together but they are able to move, slide or flow past each other.

Which of the following structures divide and multiply in cases of injury or disease? Axons Dendrites Cell bodies Glial cells

Answer: Glial cells -The axon, dendrite, and cell body are all parts of a neuron which is primarily responsible for transmission of information/ impulses to and from various organs of the body. In cases of injury and disease, neurons do not undergo cell division and so they die. -Glial cells perform support functions for neurons. In cases of injury or disease, glial cells undergo cell division and multiplication in order to occupy the spaces formerly occupied by a dead neuron.

Which of the following is a heterotrophic organism with a genome stored in DNA? Virus Plants Human Algae

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.

In order to break apart a polysaccharide into disaccharides, what type of reaction needs to occur? Condensation Hydrolysis Oxidation-reduction Glycosidic

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.

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

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.

Which of the following compounds contains ionic bonds? C6H6 CH4 O2 NaBr

Answer: NaBr -Ionic bonds form when elements from opposite sides of the periodic table form an ionic compound. In the question above, Na is a metal from the left side of the periodic table, and Br is a nonmetal from the right side of the periodic table. -Covalent bonds are formed when nonmetals (including H) form a compound. Carbon (C), hydrogen (H), and (O) are all examples of nonmetals, so all of the other options are examples of covalent compounds.

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

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.

Which of the following enzymes is responsible for catalyzing the formation of glucose and galactose? Trypsin Catalase Lactase Lipase

Answer: Lactase -Lactase is an enzyme that catalyzes the formation of glucose and galactose. Lactose intolerance is caused by a shortage of lactase enzymes, which causes an inability to digest lactose and results in digestive symptoms. -Trypsin is found in the digestive system of many vertebrates, where it hydrolyzes proteins. -Catalase catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting the cell from oxidative damage by reactive oxygen species (ROS). -Lipases catalyze the hydrolysis (breakdown) of fats.

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.

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. -A solid has a definite shape and volume. There are two kinds of solids—crystalline and amorphous.

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.

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 9:3:3:1 -This leads us to the understanding that long and orange fur is dominant.

Which of the following is not a monosaccharide? Glucose Ribose Maltose Glyceraldehyde

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.

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

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 substances will not dissolve in water? NaCl Mg(OH)2 NH4NO3 C2H5OH

Answer: Mg(OH)2 -Hydroxides are generally insoluble. Mg(OH)2 is insoluble in water. This means it will not dissolve into solution by breaking apart into magnesium ions and hydroxide ions. This is most likely due to the fact that Magnesium (Mg) is a stronger attractor of the OH- ions in comparison to the Hydrogen atoms in water. -Ionic compounds, such as sodium chloride (NaCl), are highly soluble in water. Because water molecules are polar, they interact with the sodium and chloride ions. This is because polar molecules have atoms with partial positive and negative charges, so they are able to interact with the positively and negatively charged sodium and chloride ions. -Water also dissolves non-ionic substances. For example, C2H5OH (ethanol) is very soluble in H2O. This is because C2H5OH has a polar OH bond. -When an ionic substance (salt) dissolves in water, it is broken up into individual cations and anions which are surrounded by water molecules. For example, when NH4 NO3 is dissolved in water, it breaks up into separate ions.

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

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 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

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

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

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 statements about osmosis is true? Osmotic pressure is the main cause plant cell death Osmosis is the diffusion of salt Osmosis involves a selectively permeable membrane Osmosis involves the movement of water from regions of high solute concentration to regions of low solute concentration.

Answer: Osmosis involves a selectively permeable 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. -Osmosis is a vital process in biological systems, since biological membranes are semipermeable. This means that these membranes do not generally allow large or polar molecules to cross (e.g. ions, proteins, polysaccharides, etc.). They will allow (are permeable to) non-polar, hydrophobic molecules such as lipids, as well as small molecules like oxygen, carbon dioxide, and nitrogen. -Water molecules move across a selectively permeable membrane that transports the water through proteins called aquaporins. -Osmotic pressure is the main cause of support in many plants. The osmotic entry of water raises the turgor pressure exerted against the cell wall, until it equals the osmotic pressure, creating a steady state. Therefore, it does not play a role in plant cell death.

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

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.

______ 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

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 causes bone matrix synthesis and calcification? Osteoclasts Hydroxyapatite Osteoblasts Osteoporosis

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 causes bone matrix resorption during bone growth and remodeling? Osteocytes Osteoblasts Osteoclasts Osteons

Answer: Osteoclasts -Osteoclasts are the resident macrophages of the bones, which are essential for bone matrix resorption during bone growth and remodeling. -Osteoblasts are the cells responsible for bone matrix synthesis and calcification, while osteocytes are responsible for maintenance of calcified bone matrix. -Osteons are the structural unit of compact bone characterized by concentric bone layers surrounding a central canal.

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

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.

Sesamoid bones develop from tendons. Which of the following are sesamoid bones? Scapulae Metatarsals Patellae Phalanges

Answer: Patellae -The patellae are the kneecaps. They develop from the tendon of the quadriceps femoris muscle of the thigh. -Metatarsals are short bones while phalanges are long bones. -Scapulae is an example of flat bone. -Phalanges are the finger bones.

________ 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

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.

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

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).

In the presence of antidiuretic hormone (ADH), or vasopressin, water is mostly reabsorbed in the ___________ of the nephron. Distal convoluted tubule Loop of henle Proximal convoluted tubule Collecting duct

Answer: Proximal convoluted tubule -60-70% of water is reabsorbed in the proximal convoluted tubules. -The collecting duct also plays a role in reabsorbing water in the presence of ADH or vasopressin, but it only absorbs around 10% of the water in the filtrate.

Where are the glomeruli and Bowman's capsules found? Renal cortex Renal pelvis Ureter Renal column

Answer: Renal Cortex The glomeruli and Bowman's capsules are part of the nephrons, and are found in the renal cortex.

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

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 true about SI Units? There are 8 SI base units. The SI base units can be broken down into other units. SI Units are derived from the Imperial System. SI Units are the standard measurement system in science.

Answer: SI units are the standard measurement system in science. -SI Units are a common way to communicate measurements to other scientists around the world. This way, everyone uses the same system of measurement instead of having to convert between many different systems from around the world. There are only 7 SI base units (meter, kelvin, ampere, coulomb, mole, meter, and kilogram), which are fundamental and cannot be broken down any further. The Imperial System is an older form of measurement that only three countries still use.

Which of the following is a substance that the kidneys remove from the blood during filtration? Carbon Dioxide Salts Oxygen Red Blood Cells

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.

Which of the following is the basic contractile unit of the skeletal muscle? Z-disc Sarcomere Sarcoplasmic Reticulum Sarcolemma

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.

Dandelions → Snail → Frog → Bird → Fox Using the food chain above, which of the following terms best describes the trophic level of frogs? Producer Primary consumer Tertiary consumer Secondary consumer

Answer: Secondary consumer -Secondary consumers are organisms that eat primary consumers for energy. Primary consumers are always herbivores, or organisms that only eat autotrophic plants. However, secondary consumers can either be carnivores (only eat meat) or omnivores (eat both meat and plants). -Plants are called producers. This is because they produce their own food. They do this by using light energy from the Sun, carbon dioxide from the air and water from the soil to produce food - in the form of glucose/sugar.

Which of the following functions in producing sperm? Fallopian tube Seminiferous tubules Vas deferens Urethra

Answer: Seminiferous tubules -Seminiferous tubules are the tightly coiled tubules within the testes (male gonads) where sperm production occurs. From the testes, sperm travels via the vas deferens and urethra. -In females, from the gonads, gametes travel via the fallopian tubes.

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

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 conditions occurs when a blood vessel in the brain becomes blocked? Migraine Myocardial infarction Aneurysm Stroke

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.

Blood vessels that supply nutrients and oxygen enter the bone tissues through the __________. Osteons Lacunae Lamellae Volkmann canals

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.

Blood pressure is recorded as two numbers, for example 110/70. The top number (110) represents ___________ blood pressure which is ____________________________. Systole; the pressure in the blood vessels while the heart is filling Diastole; the pressure in the blood vessels while the heart is ejecting blood Systole; the pressure in the blood vessels while the heart is ejecting blood Diastole; the pressure in the blood vessels while the heart is filling

Answer: Systole; the pressure in the blood vessels while the heart is ejecting blood -One cardiac cycle consists of one period of diastole, and one period of systole. During diastole, the heart relaxes allowing the chambers to fill with blood. During systole, a large portion of that blood is pumped out of the ventricle. During periods of rest, diastole is usually longer than systole to allow more time for filling. -In a blood pressure recording the top number represents systole, while the bottom number represents diastole.

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

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.

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

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 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.

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 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

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 statements correctly describes "sublimation"? The transition of a liquid to solid The transition of a substance from solid to gas without passing through the liquid state A transition between two types of liquid A transition between two gases

Answer: The transition of a substance from solid to gas without passing through the liquid state Sublimation is the phase change that occurs when a substance goes directly from a solid to a gas. When sublimation occurs, the substance does not go through the liquid phase. Energy is required for a solid to sublime into a gas. In nature, the heat produced by sunlight is usually the energy source.

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.

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 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

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.

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

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 of the following characteristics applies to the bonds holding together nonpolar covalent molecules? They can be formed only between two different atoms They occur when two atoms share a pair of electrons with each other They occur when two atoms share a pair of metal ions with each other They can be formed only between two identical atoms

Answer: They occur when two atoms share a pair of electrons with each other -Nonpolar covalent bonds are a chemical bond that exists between two atoms. This bond is formed when electrons are equally shared between two atoms. These bonds can be either formed between two identical atoms or between different atoms. (This is the opposite of polar molecules, which do not share electrons equally and therefore contain atoms with partial positive and negative charges.) -An example of a nonpolar covalent bond is the bond between two hydrogen atoms because they equally share the electrons. Another example of a nonpolar covalent bond is the bond between two chlorine atoms because they also equally share the electrons. Nonpolar covalent bonds are very strong bonds requiring a large amount of energy to break the bond.

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

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.

Which of the following steps of protein synthesis occurs in the nucleus? Elongation Translation to amino acid Transcription to mRNA Replication

Answer: Transcription to mRNA Protein synthesis is comprised of two main steps, transcription of DNA to mRNA and translation of mRNA codons to amino acids. In the nucleus, the mRNA transcribes the genetic instruction from the DNA. mRNA then diffuses to the cytoplasm through the nuclear pores. Translation to amino acid and elongation to a particular protein molecule occur in the cytoplasm, particularly in the ribosomes.

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

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 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.

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.

Which of the following terms correctly describes the movement of air in and out of the lungs? Respiration Ventilation Oxidation Diffusion

Answer: Ventilation -Ventilation is the physical movement of air in and out of the lungs. -Respiration is the use of oxygen by a cell or organism to make energy. -Oxidation refers to a chemical process in which a molecule loses electrons. -Diffusion is the passive movement of a substance from high concentration to low concentration.

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

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.

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.

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.

One of the primary functions of the kidney is to filter blood in order to remove substances that have no useful function in the body. Which of the following is the correct path of blood from the abdominal aorta to the inferior vena cava (IVC)? abdominal aorta - renal arteries - interlobar arteries - segmental arteries - arcuate arteries - interlobular arteries - afferent arteries - glomerulus - efferent arteries - peritubular capillaries - interlobular veins - arcuate veins - interlobar veins - renal veins - inferior vena cava abdominal aorta - renal arteries - segmental arteries - interlobar arteries - arcuate arteries - interlobular arteries - afferent arteries - glomerulus - efferent arteries - peritubular capillaries - interlobular veins - arcuate veins - interlobar veins - renal veins - inferior vena cava

Answer: abdominal aorta - renal arteries - segmental arteries - interlobar arteries - arcuate arteries - interlobular arteries - afferent arteries - glomerulus - efferent arteries - peritubular capillaries - interlobular veins - arcuate veins - interlobar veins - renal veins - inferior vena cava

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

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.

The condition ________________ can often lead to ________________ due to buildup and blockage of coronary arteries, preventing blood flow to the myocardium. arteriosclerosis; stroke arteriosclerosis; myocardial infarction atherosclerosis; myocardial infarction atherosclerosis; stroke

Answer: atherosclerosis; myocardial infarction -Atherosclerosis is the buildup of plaque inside the arteries. If the plaque buildup is severe, a blockage can result, preventing blood flow to the associated heart tissue. This is a myocardial infarction, or heart attack. This can also occur if a plaque ruptures, travels through the vessels, and becomes lodged in a coronary artery. -Arteriosclerosis is the hardening and narrowing of the blood vessels and though blood flow can be restricted, this is not the cause of buildup or blockage. -A stroke can occur if a blood vessel in the brain becomes blocked by an embolism (embolism is the word we use for any material that blocks a blood vessel).

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

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 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

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.

Humans are _________, meaning their chromosome set number is _________. Gametes of mammals are _________ cells, with a chromosome set number of ________. diploid, 2n; haploid, n haploid, 6n; monoploid, n diploid, n; triploid, 2n polyploid, n; haploid, 4n

Answer: diploid, 2n; haploid, n A diploid cell is a cell that contains two sets of chromosomes. A haploid cell only contains one set of chromosomes. Gametes (sperm and egg cells) are haploid cells. During sexual reproduction, gametes fuse at fertilization to form a diploid zygote. The zygote develops into a diploid organism.

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

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.

In a redox reaction, the oxidizing agent _______ electrons and the reducing agent _______ electrons. loses, gains gains, loses loses, loses gains, gains

Answer: gains, loses -In a redox reaction, the oxidizing agent causes another reagent to lose electrons, so the oxidizing agent is reduced (gains electrons). -The reducing agent reduces another substance, so the reducing agent is oxidized (loses electrons).

Movement of molecules in a substance depends on _______ energy. Gamma ray heat X-ray UV

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.

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

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).

Correctly order the following prefixes from smallest to largest: milli, kilo, deci, micro, nano. milli, nano, kilo, deci, micro nano, milli, kilo, deci, micro nano, micro, milli, deci, kilo deci, micro, nano, milli, kilo

Answer: nano, micro, milli, deci, kilo These prefixes are used to communicate the scale of measurements to other scientists. The nano prefix is used to indicate 10-9 micro is 10-6, milli is 10-3, deci is 10-1, and kilo is 103. Remember: the more negative the exponent is, the smaller the number.

The term _________________ refers to the contraction of smooth muscle in the digestive system that moves food along the GI tract. retroperistalsis segmentation vasoconstriction peristalsis

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.

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

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.