ATI TEAS Science Diagnostic Test

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

- 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, & the average mass of a laptop is 2.5 kg.

Which of the following is incorrect about muscle contraction? - Actin & myosin filaments shorten during contraction. - Neurotransmitters stimulate muscle contraction. - Sarcomeres shorten during contraction. - Muscle contraction requires ATP.

- Actin & myosin filaments shorten during contraction. Muscle contraction occurs upon stimulation of neurotransmitters released in the neuromuscular jxn. The process requires ATP & involves shortening of sarcomeres by the sliding of actin & myosin past each other. The length of actin & myosin filaments does not change during contraction.

The same single-replacement reaction is run in 2 different beakers. The beakers are labeled as Beaker A & 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? - Beaker A produces more product than Beaker B - No products are produced in either beaker - The 2 beakers produce the same amount of product - Beaker B produces more product than Beaker A

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

Which of the following is the most plausible sequence of events? - Born into musical family; grows up around music; starts learning guitar; plays concert - Walk in the woods; stung by bee; given morphine; early death - Poaching more rhinos; more export rhino horn goods; more goods with a lower economic value; economy boost - Extensive car use; air pollution; less people with asthma; less healthcare expenses

- Born into musical family; grows up around music; starts learning guitar; plays concert Children who are born into families that prioritize a specific activity are typically more inclined to be exposed to that activity at a young age & after years of practice, they excel at that activity. Ozone can make it more difficult for you to breathe deeply. Airborne particles, found in haze, smoke & airborne dust, present serious air quality problems. Ppl w/ asthma are at greater risk from breathing in small particles Usually, bee stings don't cause a serious rxn. However, if you're allergic to bee stings or have had several bee stings, you may experience a severe rxn such as poisoning. Bee poisoning requires immediate medical attention. Taking an antihistamine such as diphenhydramine (Benadryl) or a nonsedating 1 such as loratadine (Claritin) will help w/ itching & swelling. Illegal wildlife trade is also often unsustainable, harming wild populations of animals & plants & pushing endangered species toward extinction. Endangered animals & plants are often the target of wildlife crime bc of their rarity & increased economic value. The bans are implemented largely thru the Convention on the International Trade in Endangered Species of Fauna & Flora (CITES) & supplemented thru EU & US trade measures.

Balance the following chemical equation: CH4 + Cl2 → CCl4 + HCl - 2 CH4 + 2 Cl2 → 2 CCl4 + 2 HCl - CH4 + 4 Cl2 → CCl4 + 4 HCl - CH4 + Cl2 → CCl4 + HCl - 2 CH4 + Cl2 → 2 CCl4 + HCl

- CH4 + 4 Cl2 → CCl4 + 4 HCl To balance equations, it is helpful to write down the # of atoms of each element present in both the reactants & products. Change the coefficients of the reactants & products until the same # of atoms of each element is present on both sides of the rxn arrow. CH4 + Cl2 → CCl4 + HCl C: 1 C: 1 H: 4 H: 1 Cl: 2 Cl: 5 CH4 + Cl2 → CCl4 + 4 HCl C: 1 C: 1 H: 4 H: 4 Cl: 2 Cl: 8 CH4 + 4 Cl2 → CCl4 + 4 HCl C: 1 C: 1 H: 4 H: 4 Cl: 8 Cl: 8

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

- 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 & moves through the cervix to reach the uterus, then finally the fallopian tubes.

Which of the following is the most accurate description of the link between chromosomes and DNA? - The DNA sequence is made up of chromosomes, which include numerous genes. - Chromosomes include numerous genes, each of which is made up of a DNA sequence. - Chromosomes are the building blocks of DNA. - Genes contain chromosomes that are made up of DNA.

- Chromosomes include numerous genes, each of which is made up of a DNA sequence. Chromosomes carry genetic info in the form of DNA. Each gene is formed of sequences of DNA & carries info for characteristics of organisms. A chromosome is made up of DNA & protein, so chromosomes cannot be considered the building blocks of DNA. DNA is not formed by a sequence of chromosomes. Chromosomes are made up of DNA. Chromosomes contain genes. Genes do not contain chromosomes.

Which of the following is not true about thermoregulation? - Cutaneous vasodilation cools the body by allowing heat to be released through skin. - Cutaneous vasoconstriction warms the body by restricting blood flow in the skin. - Contraction of arrector pili muscles facilitates vasodilation. - Sweating facilitates cutaneous vasodilation.

- Contraction of arrector pili muscles facilitates vasodilation. Contraction of arrector pili muscle facilitates cutaneous vasoconstriction (constriction of the blood vessels), while relaxation facilitates vasodilation (dilation of the blood vessels). Cutaneous vasodilation cools the body by allowing heat to be released through skin, while cutaneous vasoconstriction warms the body by restricting blood flow in the skin. Production of sweat by the eccrine glands facilitates cooling of the body.

Enzymes are biological catalysts that ___________. - Increase the rate of any given reaction - Use up the substrate molecules in the reaction - Bind to the products - Are necessary to convert substrate into products

- Increase the rate of any given reaction Enzymes act as biological catalysts & increase the rate of a rxn by reducing the activation nrg needed to begin a rxn. Enzymes do not use substrate mlc's (the starting mlc's). They help increase the rate of a rxn. Enzymes are not necessary for the conversion of substrates into products. They just increase the rate of rxn & speed up the formation of the products. Enzymes do not bind to the products. They bind to the substrates to reduce the activation nrg & catalyze the rxn.

Which of the following statements about diffusion is true? - Diffusion is the net mvt of mlc's or atoms from a region of higher concentration to a region of lower concentration - Gas exchange in tissues in not an example of diffusion - Osmosis is not an example of diffusion - Diffusion is the net mvt of mlc's or atoms from a region of lower concentration to a region of higher concentration

- Diffusion is the net mvt of mlc's or atoms from a region of higher concentration to a region of lower concentration Diffusion is the passive mvt (meaning that no additional nrg is needed to facilitate the mvt) of particles (atoms, ions or mlc's) from a region in which they are in higher concentration to regions of lower concentration. This process continues until the concentration of substances is uniform (equivalent) throughout. Gas exchange for respiration is an example of diffusion — O2 from blood to tissue cells, CO2 in the opposite direction. Osmosis is also an example of diffusion— diffusion of water thru a semipermeable membrane.

Which of the following hormones is not increased in plasma during dehydration? - Antidiuretic hormone - Aldosterone - Renin - Erythropoietin

- Erythropoietin During dehydration, secretions of antidiuretic hormone, renin, & aldosterone are increased in order to prevent further loss of water in the urine. Erythropoietin is produced in the kidney in response to low levels of oxygen (hypoxia) in order to stimulate production of RBCs.

Which of the following descriptions is correct? - Liquid: no definite volume & constant shape - Gas: constant volume & a definite shape - Solid: no constant volume & no constant shape - Gas: no definite volume & no definite shape

- Gas: no definite volume & no definite shape A gas is a substance w/ no definite volume & no definite shape. Solids & liquids have volumes that do not change easily. A solid has a definite shape and volume. There are 2 kinds of solids—crystalline & amorphous. Liquids can occupy whatever shape their container has, so they do not have a fixed shape. Bc 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 lipid or fat molecule can be broken down into its monomers, one of which is __________. - Glucose - Amino acid - Nucleic acid - Glycerol

- Glycerol Glycerol & fatty acids are the monomers of lipid or fat molecules. Nucleic acid is not a monomer. It is a macromlc formed of nucleotides. Glucose is a monomer of polysaccharides. Amino acid is a monomer of proteins.

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

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

The genotypes of the parents in the Punnett square below can be described as __________. {RR - top left} {RR - bottom left} {Rr - top right} {Rr - bottom right} - Heterozygous recessive & heterozygous dominant - Heterozygous dominant & homozygous dominant - Heterozygous recessive & homozygous recessive - Homozygous dominant & homozygous recessive

- Heterozygous dominant & homozygous dominant The parents' genotypes are heterozygous dominant (Rr) & homozygous dominant (RR). We can see this by going across the top (Rr) & down the side (RR). Remember that heterozygous means the offspring has a combination of different alleles, whereas homozygous means that they only have copies of the same exact allele. The genotype contains all dominant alleles. Homozygous dominant (RR) & heterozygous dominant (Rr) suppress the activity of the r allele. Therefore, none of the possible genetic combinations would result in a recessive pairing. There are no homozygous recessive alleles in both parents. 1 of the parents shows the presence of homozygous dominant alleles but the other 1 does not contain homozygous recessive alleles. This means that each possible cross will always contain at least 1 dominant allele, so the dominant trait will be expressed in all of the offspring.

Review the data in this table, & then choose the statement that draws the best conclusion? - Hours spent sleeping & score on the test correlate negatively w/ 1 another - Hours spent sleeping & score on the test correlate w/ 1 another - There is no correlation between sleep time & test score - Amount of time spent sleeping is the cause of what test score was received

- Hours spent sleeping & score on the test correlate w/ 1 another Correlation is a statistical measure that indicates the extent to which 2 or more variables change together. A (+) correlation indicates that the variables are increasing or decreasing together (in parallel). A (-) correlation indicates that as 1 variable increases the other decreases. In this example, time spent sleeping correlated positively w/ the obtained test score. In statistics, when the value of 1 event, or variable, increases or decreases as a result of other events, it is said there is causation. This is not the best conclusion for our example, since, for example, people who have slept 8 & 8.2 hours have the same test score.

Which of these bonds would we see between nitrogenous bases? - Ionic bonds - Polar bonds - Sulphide bonds - Hydrogen bonds

- Hydrogen bonds Between nitrogenous bases, hydrogen bonds are seen since this bond is easy to break, which is needed during the processes of replication & transcription. Ionic bonds are seen between ions. Nitrogenous bases are not ions. Nitrogenous bases do not form sulfide bonds. Nitrogenous bases are not polar in nature & do not form polar bonds.

Which of the following is a hypothesis? - When I added fertilizer to my plants, they grew more quickly. - 5 different breeds of dogs are at the dog park. - If a student gets more sleep, they will get a higher test score. - 1 liter of water was added to a rxn.

- If a student gets more sleep, they will get a higher test score. A hypothesis is an explanation for observed phenomena. The other options are merely observations from which hypotheses could be constructed.

Melatonin is the hormone that regulates sleep-and-wake rhythm. Which of the following endocrine glands is responsible for producing melatonin? - Pituitary - Hypothalamus - Adrenal - Pineal

- Pineal Melatonin, the hormone that regulates sleep-and-wake rhythm, is produced by the cells in pineal gland. Both the hypothalamus & pituitary glands coordinate the fxn of other endocrine glands by producing stimulatory & inhibitory hormones. Adrenal glands produce the hormones cortisol & aldosterone.

Which of the following is true of insulin and glucagon? - Insulin & glucagon have opposite effects on blood glucose but work together to maintain homeostasis. - Insulin & glucagon maintain normal levels of blood glucose in the fasting state. - Insulin & glucagon regulate the level of calcium in the blood. - Secretion of insulin & glucagon is regulated by the pituitary gland.

- Insulin & glucagon have opposite effects on blood glucose but work together to maintain homeostasis. Insulin & glucagon are both secreted by the pancreas & fxn in the homeostatic maintenance of the blood's glucose level. Insulin decreases the level of the blood's glucose during a fed state & glucagon increases levels of glucose during a fasting state.

Which of the following does not describe a sarcomere? - It is made up of fibrous protein filaments. - It is the contractile unit of a muscle. - It completely surrounds the muscle fiber. - It shortens in length when actin & myosin slide past each other during contraction.

- It completely surrounds the muscle fiber. The sarcomere is the contractile unit of a muscle made up of fibrous protein filaments, actin & myosin. During contraction, the sarcomere shortens in length when actin & myosin slide past each other. The structure that surrounds the muscle fiber is called the sarcolemma.

Which of the following correctly describes the law of segregation? - It states that the heredity factors segregate independently on 1 another during gametogenesis - It states that allele pairs segregate during gametogenesis & reunite randomly during the fertilization process - It states that the segregation of the dominant trait in the phenotype happens in the hybrid offspring - It states that all the genetic factors are present in the DNA

- It states that allele pairs segregate during gametogenesis & reunite randomly during the fertilization process The law of segregation states that each pair of alleles segregate randomly during gametogenesis (gamete formation). This means that each gamete (sex cell) receives 1 copy of a gene (an allele). They later reunite or combine randomly during fertilization. This way, the offspring acquires 1 allele from each of the parents. The law of dominance states that the offspring will always display the dominant trait in the phenotype by suppressing the recessive trait. The law of independent assortment states that the traits inherited by the offspring are independent of each other. Two or more traits do not influence one another. The law of segregation does not state anything about storing genetic information in the DNA.

Which of the following prefixes would likely be the most appropriate for measuring the weight of a 2,500 g kitten? - Kilo - Giga - Nano - Pico

- Kilo The purpose of scientific notations & prefixes is to avoid writing extremely long #'s. So, the correct answer to this question would be whichever option resulted in the smallest # of 0s. In kilograms, the mass of the kitten is 2.5 kg. If it was written as gigagrams, it would be 0.0000025 gigagrams, & in nanograms, it is 2,500,000,000,000 ng. In picograms, it would be 2,500,000,000,000,000. As you can see, kg results in the fewest digits, so it is the most appropriate prefix to use here.

Which of the following is not true about reproductive hormones? - FSH (follicle-stimulating hormone) stimulates maturation of sperm and ovum. - LH (luteinizing hormone) stimulates ovulation and production of testosterone. - FSH (follicle-stimulating hormone) is produced by the anterior pituitary gland. - LH (luteinizing hormone) is produced by the posterior pituitary gland.

- LH (luteinizing hormone) is produced by the posterior pituitary gland. FSH (follicle-stimulating hormone) & LH (luteinizing hormone), which primarily regulate fxn of male & female reproductive systems, are both produced in a synchronized manner by the anterior pituitary gland. FSH is primarily involved in the maturation of sperm & ovum (follicles) and LH stimulates ovulation & production of testosterone.

Using the provided image, choose the anatomical structure designated by letter B. - Right ventricle - Left atrium - Left ventricle - Right atrium

- Left atrium

Which of the following is the process by which gametes divide and produce half the number of chromosomes found in a somatic cell? - Meiosis - Gametes - Fertilization - Zygote

- Meiosis Meiosis is the process by which gametes divide and produce half the # 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 1 division during mitosis. The 2nd 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 & female sex cell which contain half set of chromosomes. Fertilization is the process of union of male & female gametes which result to a fertilized egg, or zygote, which contains a full set of chromosomes.

As air is inhaled, the sequence in which it passes through the respiratory tract is best described by which of the following choices? - Nasal cavity, trachea, pharynx, larynx, bronchioles, bronchi - Nasal cavity, bronchi, bronchioles, trachea, pharynx, larynx - Nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles - Pharynx, nasal cavity, larynx, trachea, bronchi, bronchioles

- Nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles When inhaling, air is taken in thru the mouth & nose, & then thru the larynx & pharynx. These passageways warm the air & prepare it for gas exchange. The air continues on thru the trachea, commonly referred to as the "windpipe". The trachea then splits into a right & left bronchi, w/ each side dividing further into smaller bronchioles. While some bronchioles may directly be involved in gas exchange, the majority of them are part of the conducting airway, which simply moves air thru the respiratory system to get them to the alveoli where most of the gas exchange occurs.

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? - Tissue - Organ System - Organ - Organelle

- Organ System Tissues are a collection of specialized cells that perform a specific fxn's (e.g. protection, support, nerve conduction & mvt). 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 fxn's is an organ system.

Which of the following causes bone matrix resorption during bone growth and remodeling? - Osteoblasts - Osteons - Osteoclasts - Osteocytes

- Osteoclasts Osteoclasts are the resident macrophages of the bones, which are essential for bone matrix resorption during bone growth & remodeling. Osteoblasts are the cells responsible for bone matrix synthesis & 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.

In which segment of the nephron is glucose reabsorbed? - Collecting duct - Proximal convoluted tubule - Loop of henle - Distal convoluted tubule

- Proximal convoluted tubule Glucose, amino acids, & the majority of electrolytes & water are reabsorbed in the proximal convoluted tubules via facilitated diffusion & active transport

Which of these is a function of a ribosome? - Ribosomes transfer mRNA from the nucleus to the cytoplasm. - Ribosomes move along the length of the amino acid chain to introduce peptide bonds in between them. - Ribosomes can decode mRNA & assemble amino acids for protein synthesis. - Ribosomes carry the codons required for protein synthesis.

- Ribosomes can decode mRNA & assemble amino acids for protein synthesis. Ribosomal units can decode the codons on mRNA & assemble amino acids w/ the help of tRNA for translation. Codons are contained w/in the mRNA strand, not on or inside the ribosomes. Ribosomes do not move along the length of an amino acid chain, they create 1. They move along the mRNA strand to decode it, which then directs the formation of the complementary amino acid chain. The transfer of mRNA from the nucleus to the cytoplasm does not occur w/ the help of tRNA.

A scientist collected the following set of data to examine the effects of exercise on patients' heart rates. Patients were tasked w/ running 1 mile everyday for 3 days in the presence of the scientists. They were required to run the entire mile & were not allowed to walk. At the end of each mile run, the scientists measured the heart rates of the patients. Which of the following conclusions can be drawn from this data? - Patients that ran the mile faster had higher heart rates - Running increased the heart rates of the patients - The patients ran Mile 3 faster than Mile 1 - The patients became fitter w/ each mile run

- Running increased the heart rates of the patients From the data, it is clear that the heart rate of patients after running was much higher than their resting heart rates. There is no info provided about the pace at which the patients ran the miles. While it is certainly possible, & even likely, that running the miles increased the patients' fitness levels, there is no data provided above to support this claim.

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

- 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? - Sarcolemma - Sarcoplasmic Reticulum - Sarcomere - Z-disc

- Sarcomere The sarcomere is the basic contractile unit of the skeletal muscle made of thin & 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 correctly describes the difference between compact bone and spongy bone? - Compact bone is located more interior than spongy bone - Compact bone has trabeculae that support the bone marrow - Spongy bone is lighter than compact bone - Spongy bone has more osteons than compact bone

- Spongy bone is lighter than compact bone Compact bone is composed of repeating units of osteons & is the strongest form of bone tissue. On the contrary, spongy bone is lighter than compact bone tissue & is always located on the interior of the bone. Rather than osteons, spongy bone is also made of thin columns of trabeculae which cover & protect the bone marrow.

Dissolved oxygen (DO) is an important indicator of water quality, & O2 levels that are too high or too low can harm aquatic ecosystems. A biologist noticed that fish were dying in a local lake & 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 fxn of temperature. To do this, she heated several samples of lake water to various temperatures & 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 - Dissolved oxygen concentration - Location of the lake - Temperature

- 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.

The number of protons is the same as? - The atomic number - The nuclear force - The angular momentum - Number of isotopes for the element

- The atomic number The # of protons in the nucleus of an atom is known as the atomic #, which determines the chemical element to which the atom belongs. All atoms of a given element are not necessarily identical. For example, elements may have isotopes, which are atoms of the same element w/ different #'s of neutrons. The # of possible isotopes is not connected to the # of protons in an atom. The # of protons in the nucleus is the defining property of an element, & is referred to as the atomic #. The nuclear force is a force that acts between the protons & neutrons of atoms.

Which of the following does not describe the dermis? - The layer of the skin where cells containing the pigment melanin are found - The thickest layer of the skin - The layer of the skin that contains the network of capillaries necessary for thermoregulation - A vascular layer of the skin

- 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 & 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 statements is true about protons? - They have more mass than a neutron. - The number of protons in the nucleus is the defining property of an element. - They have a negative charge. - Some atoms have no protons.

- The number of protons in the nucleus is the defining property of an element. A proton is a subatomic particle that has a charge of +1. Every atom has at least 1 proton in its nucleus. The # of protons in the nucleus is the defining property of an element & is referred to as the element's atomic #. For example, any atom w/ 1 proton must be hydrogen; any atom w/ 6 protons must be carbon.

Which of the following statements is true about hydrogen bonds? - They result from the attraction between ions that have no charge - They are considered strong attractive forces - They don't affect the properties of water in any way - They form between a partial positively charged region on 1 mlc & the partial negatively charged region on another mlc

- They form between a partial positively charged region on 1 mlc & the partial negatively charged region on another mlc Hydrogen bonding occurs between mlc's when at least 1 contains a hydrogen atom & both mlc's have a small electric charge bc the molecule is polar. Polar mlc's, such as water, result from 1 atom having a stronger pull on the shared electrons, which causes the atoms to have slight (-) or (+) charges. The slight (+) charge of the hydrogen atoms allow them to form hydrogen bonds w/ the atoms in other polar mlc's w/ slightly (-) charges. Altho 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 & covalent bonds. Water is strongly affected by hydrogen bonding. Bc the hydrogen bonds attract water mlc's to 1 another, water is more tightly packed in liquid form than in solid form, where the mlc's are held further apart in a lattice.

T-lymphocytes mature and become functional in which of the following organs? - Lymph nodes - Thymus - Spleen - Bone marrow

- Thymus Lymphocytes are produced in the bone marrow, but mature & become fxn'al in 2 primary lymphoid organs. B-lymphocytes differentiate & mature in the bone marrow, while T-lymphocytes becomes fxn'al in the Thymus.

Why are control groups used in experiments? - To increase the amount of data collected - To help scientists quickly perform experiments - To ensure the accuracy of measurements - To minimize the effect of variables

- To minimize the effect of variables A control group is used to ensure that the # 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 correctly describes anatomical position? - Supine, arms at sides, palms facing posteriorly - Seated, arms at sides, palms facing posteriorly - Upright, arms at sides, palms facing anteriorly - Prone, arms at sides, palms facing anteriorly

- Upright, arms at sides, palms facing anteriorly Anatomical position is described as standing erect, arms at sides, face and palms are facing anteriorly (facing to the front).

Which of the following comparisons between arteries & veins is true? - Veins have a smaller diameter than arteries. - Veins have valves, and arteries do not. - Veins have thick, muscular walls, while arteries have thin, more compliant walls. - Veins carry freshly oxygenated blood from tissue back to the heart, while arteries carry oxygen-depleted blood away from the heart

- Veins have valves, and arteries do not. Due to the lower pressure in the venous system & 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 O2, therefore they carry oxygen-depleted blood, along w/ 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 O2 can be delivered & used for cellular respiration. Due to the higher pressure in which arterial blood must flow, arteries have thicker walls & smaller lumen, or diameter, as compared to veins. Veins are often considered to be capacitance vessels as they carry a larger volume of blood, & have thinner walls, and greater wall compliance to accommodate the higher volume of blood.

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

- heat All matter is made of particles called atoms (which make up mlc's). These atoms & mlc's are always in motion - bumping into each other or vibrating back & forth. Heat is a form of nrg that is created thru the mvt of atoms & mlc's. The amount of mvt of mlc's in a substance increases as it gains heat & decreases as it loses heat. At higher temperatures, particles have more nrg. Some of this nrg can be transmitted to other particles that are at a lower temperature. There are many types of electromagnetic waves. From lowest nrg to highest nrg there are radio waves, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays. They do not affect the mvt of particles in substances.

Gas exchange between the blood & alveoli would be enhanced by ______________, but impeded by __________________. - decreased membrane thickness; increased alveolar surface area - decreased respiratory rate; increased tidal volume - increased tidal volume; decreased membrane thickness - increased alveolar surface area; increased membrane thickness

- increased alveolar surface area; increased membrane thickness Gas exchange in the lung can be explained by Fick's Law of Diffusion, which is represented by the following equation: Diffusion = k * SA * ( P2 - P1)⁄T where k represents the diffusion coefficient for the specific gas, SA represents the surface area of the tissue, P2- P1 represents the difference in the gas concentration on 1 side of the membrane compared to the other side, & T represents the thickness of the tissue. Thus, any increases in gas coefficient, surface area, or difference in pressure will enhance gas exchange, while any increase in tissue thickness will impede gas exchange.

Which of the following is a function of the epidermis? - contains many blood vessels that can constrict or dilate for thermoregulation - functions as a major component of the adaptive immune system - storage of fat - protects underlying tissues from abrasions, heat, microbes, and chemicals

- protects underlying tissues from abrasions, heat, microbes, and chemicals The epidermis, as the outermost layer of the skin, protects underlying tissues from abrasions, heat, microbes, & chemicals. It fxn's as a major component of the innate immune system (the "general" immune system that targets anything seen as "foreign"). It is avascular, so it does not contain blood vessels. Lipid-containing cells are found in the subcutaneous layer.

The _________________ carries oxygen depleted blood away from the heart, while the ________________ carries oxygen-rich blood back towards the heart. - aorta; pulmonary artery - vena cava; pulmonary artery - pulmonary artery; pulmonary vein - pulmonary vein; pulmonary artery

- pulmonary artery; pulmonary vein The pulmonary artery carries blood from the right ventricle to the lungs, where it can pick up oxygen. Therefore, oxygen-depleted blood is carried in the pulmonary artery. This is contrary to most arteries, which typically carry oxygen-rich blood. Once the blood is oxygenated in the lungs, it returns to the heart at the left atrium throu the pulmonary vein. Once blood has been oxygenated & returns to the left side of the heart, it can be ejected by the left ventricle throughout the body via the aorta. The vena cava returns oxygen depleted blood to the right atrium.

The majority of nutrient absorption occurs in the _________________. - small intestine - large intestine - liver - pancreas

- small intestine The small intestine is the site of the majority of nutrient absorption. The folds in the lining along w/ the length of the small intestine allows ample time for nutrients to travel through the small intestine to allow maximum absorption. The large intestine facilitates the absorption of water & some electrolytes, but typically protein has already been absorbed by the time it reaches the large intestine. The liver has several fxn's, w/ a few fxn's related to digestion such as bile secretion, but there is no absorption occurring by the liver. The pancreas secretes many digestive enzymes & hormones, but it does not absorb nutrients in the digestive tract.

Which of the following correctly pairs structure and function? - mouth / nutrient absorption - stomach / chemical digestion - colon / absorption of glucose - duodenum / reabsorption of water

- stomach / chemical digestion The stomach is responsible for chemical digestion. As food contents enter the stomach, it mixes w/ digestive enzymes & hydrochloric acid to break down food. The muscular contractions, or segmentation, that the stomach muscles produce helps to move the food around & ensure it thoroughly mixes w/ the chemicals. While mechanical digestion (i.e. chewing) & chemical breakdown begins in the mouth, nutrient absorption does not occur until the food particles are small enough for absorption and this happens in the small intestine. The duodenum is a segment of the small intestine (where most nutrient absorption takes place). However, reabsorption of water happens in the large intestine, not the small intestine. The colon is a segment of the large intestine which is primarily responsible for reabsorption of water & some electrolytes. The absorption of glucose occurs mainly in the small intestine.