Free TEAS 7 Science Exam Flashcards

Proximal means closer to the trunk or point of attachment; distal means farther from it. The knee is proximal to the ankle. These two describe limbs, while superior and inferior describe up-and-down position on the body as a whole.

Sagittal divides the body into left and right; frontal (coronal) divides anterior (front) from posterior (back); transverse divides superior (top) from inferior (bottom). A midsagittal cut produces two equal halves.

In the alveoli, thin-walled air sacs wrapped in capillaries where oxygen diffuses into blood and carbon dioxide diffuses out. The trachea, bronchi, and bronchioles only conduct air; no exchange occurs there.

The diaphragm contracts and flattens while external intercostals lift the ribs, expanding the thoracic cavity. That drops pressure inside the lungs below atmospheric pressure, so air flows in. Quiet exhalation is passive elastic recoil, requiring no muscle contraction.

Body -> vena cava -> right atrium -> tricuspid valve -> right ventricle -> pulmonary valve -> lungs -> pulmonary veins -> left atrium -> mitral (bicuspid) valve -> left ventricle -> aortic valve -> aorta -> body.

Arteries carry blood away from the heart under high pressure and have thick muscular walls. Veins return blood to the heart at low pressure and contain one-way valves. Direction defines them, not oxygen content: the pulmonary artery carries deoxygenated blood.

The pulmonary circuit runs right ventricle -> lungs -> left atrium to pick up oxygen. The systemic circuit runs left ventricle -> body -> right atrium to deliver it. The left ventricle has the thickest wall because it pumps against whole-body resistance.

In the small intestine, mainly the jejunum, where villi and microvilli create an enormous surface area. The large intestine absorbs water and electrolytes and forms feces, but absorbs very few nutrients.

Carbohydrate digestion starts in the mouth with salivary amylase. Protein digestion starts in the stomach, where hydrochloric acid converts pepsinogen into active pepsin. Most fat digestion happens later in the small intestine using bile and lipase.

The CNS is the brain and spinal cord, handling integration and command. The PNS is every nerve outside them, split into somatic (voluntary skeletal muscle) and autonomic (involuntary organs). The autonomic branch further divides into sympathetic and parasympathetic.

Sympathetic is fight or flight: raises heart rate, dilates pupils and bronchioles, slows digestion. Parasympathetic is rest and digest: lowers heart rate, constricts pupils, stimulates digestion. They act in opposition on the same organs to keep balance.

Skeletal: striated, multinucleated, voluntary, moves bones. Cardiac: striated, branched, involuntary, joined by intercalated discs, found only in the heart. Smooth: non-striated, involuntary, lines hollow organs and blood vessels.

The origin attaches to the stationary bone; the insertion attaches to the bone that moves. Muscles can only pull, never push, so they work in antagonistic pairs: the biceps flexes the elbow while the triceps extends it.

Sperm are produced in the seminiferous tubules of the testes and mature and are stored in the epididymis. The vas deferens transports them, and the seminal vesicles and prostate add fluid to form semen.

A surge of luteinizing hormone (LH) near day 14 releases the oocyte from its follicle. The ruptured follicle becomes the corpus luteum, which secretes progesterone to maintain the uterine lining. Fertilization normally occurs in the fallopian tube, not the uterus.

Epidermis (outer, avascular, keratinized), dermis (blood vessels, nerves, hair follicles, glands), and hypodermis or subcutaneous layer (fat and insulation). Because the epidermis has no blood supply, it receives nutrients by diffusion from the dermis.

Endocrine glands are ductless and release hormones straight into the bloodstream to reach distant target cells. Exocrine glands (sweat, salivary) use ducts to deliver products onto a surface or into a cavity. Hormonal effects are slower to start but last longer than nerve signals.

Insulin, from pancreatic beta cells, lowers blood glucose by driving it into cells. Glucagon, from alpha cells, raises it by breaking down liver glycogen. Together they form a negative feedback loop, the classic TEAS example of homeostasis.

The nephron. It filters blood at the glomerulus, then reabsorbs water and needed solutes and secretes wastes along the tubule. Kidneys also regulate blood pressure, blood pH, and electrolyte balance, not just urine output.

Innate immunity is nonspecific and immediate: skin, mucous membranes, inflammation, phagocytes, fever. Adaptive immunity is specific and slower, using B cells (antibodies) and T cells, and it forms memory, which is why a second exposure produces a faster, stronger response.

The axial skeleton (80 bones) is the skull, vertebral column, and rib cage, protecting central organs. The appendicular skeleton (126 bones) is the limbs plus the pectoral and pelvic girdles, enabling movement. The adult skeleton has 206 bones total.

Prokaryotes (bacteria) have no nucleus and no membrane-bound organelles; their DNA sits free in the cytoplasm. Eukaryotes (animals, plants, fungi, protists) have a true nucleus and organelles. Both still have ribosomes, a plasma membrane, cytoplasm, and DNA.

Mitochondria generate ATP through cellular respiration. Ribosomes build proteins by reading mRNA. The Golgi apparatus modifies, packages, and ships proteins arriving from the endoplasmic reticulum. Lysosomes digest cellular waste with hydrolytic enzymes.

Transcription copies DNA into messenger RNA inside the nucleus. Translation happens at the ribosome, where tRNA delivers amino acids in the order the mRNA specifies. The overall flow is DNA -> RNA -> protein.

DNA is double-stranded, contains deoxyribose, and pairs adenine with thymine and cytosine with guanine. RNA is single-stranded, contains ribose, and swaps uracil for thymine, so adenine pairs with uracil. Three mRNA bases form one codon, coding one amino acid.

Genotype is the pair of alleles carried (BB, Bb, or bb); phenotype is the observable trait. BB and Bb produce the same dominant phenotype, which is why a recessive trait can skip a generation and reappear in the children of two carriers.

Genotypes come out 1 BB : 2 Bb : 1 bb, giving a 3:1 phenotypic ratio. So 75% show the dominant trait and 25% show the recessive one, meaning each child of two carriers has a 25% chance of the recessive condition.

Carbohydrates are built from monosaccharides, proteins from amino acids, nucleic acids from nucleotides, and lipids from glycerol plus fatty acids (lipids are not true polymers). Proteins use 20 amino acids joined by peptide bonds.

It lowers activation energy so the reaction proceeds faster, and it is not consumed. Enzymes are proteins with substrate-specific active sites, and extreme heat or the wrong pH denatures them, destroying the shape and therefore the function.

Antibiotics attack bacterial structures such as the cell wall and bacterial ribosomes. Viruses are not cells, lack those structures, and must hijack a host cell to replicate, so they need antivirals or vaccines instead. Fungi and parasites are two further pathogen classes that antibiotics also do not treat.

Diffusion and osmosis move substances down a concentration gradient and cost no ATP; active transport such as the sodium-potassium pump spends ATP to move them against it. Water follows solute, so a cell in a hypertonic solution shrinks, in a hypotonic solution swells and may burst, and in an isotonic solution shows no net change.

Protons carry +1 and neutrons carry 0; both sit in the nucleus and hold nearly all the mass. Electrons carry -1, orbit in shells, and have negligible mass. The number of protons is the atomic number and defines which element it is.

An isotope has a different number of neutrons, so mass changes but charge and element identity do not. An ion has a different number of electrons, so it carries a charge: losing electrons makes a positive cation, gaining them makes a negative anion.

Solids hold their shape and volume, liquids keep volume but take the container's shape, and gases fill it. Phase changes are physical: melting, vaporizing, and subliming absorb energy while freezing, condensing, and depositing release it, and temperature holds steady during the change. A chemical change instead makes a new substance, signaled by bubbling, a precipitate, or released heat or light.

An ionic bond transfers electrons, usually from a metal to a nonmetal, and the resulting oppositely charged ions attract; these compounds have high melting points and conduct electricity when dissolved. A covalent bond shares electrons between nonmetals. Hydrogen bonds are weak attractions between molecules, and they give water its high boiling point and surface tension.

Synthesis: A + B -> AB. Decomposition: AB -> A + B. Single replacement: A + BC -> AC + B. Double replacement: AB + CD -> AD + CB. Combustion burns a hydrocarbon in oxygen to yield carbon dioxide and water. Conservation of mass requires equal atom counts on both sides, so balance with coefficients only; changing a subscript would change the substance itself.

Higher temperature, higher concentration, greater surface area, and a catalyst all increase effective molecular collisions. A catalyst lowers activation energy and is not consumed, so it changes the rate but not the products or the position of equilibrium.

The solute is the substance being dissolved; the solvent does the dissolving and is present in the greater amount. Like dissolves like, so polar solvents such as water dissolve polar and ionic solutes, while nonpolar solvents dissolve fats and oils.

Hydrogen ion concentration, on a 0 to 14 scale. Below 7 is acidic, exactly 7 is neutral, above 7 is basic. It is logarithmic, so pH 4 holds ten times more H+ than pH 5 and one hundred times more than pH 6.

Acids donate H+ ions, taste sour, and turn litmus red. Bases accept H+ or release OH-, feel slippery, and turn litmus blue. An acid plus a base neutralizes into a salt and water. Normal human blood is slightly basic at pH 7.35 to 7.45.

Meter for length, gram or kilogram for mass, liter for volume, and degrees Celsius for temperature (the kelvin is the SI temperature unit). Mass is the amount of matter and stays constant anywhere; weight is gravitational force and changes with location.

Kilo- is 1,000, hecto- 100, deka- 10, then the base unit, deci- 0.1, centi- 0.01, milli- 0.001. Each step is a factor of ten, so 1 gram equals 1,000 milligrams and 1 liter equals 1,000 milliliters.

A graduated cylinder measures liquid volume, read at the bottom of the meniscus at eye level. A balance measures mass. A thermometer measures temperature. Beakers and flasks are for holding and mixing, not for precise measurement.

A hypothesis is a testable, falsifiable prediction. A theory is a well-supported explanation backed by large amounts of evidence. A law describes what reliably happens, often as an equation, but does not explain why. A theory never gets promoted into a law.

Reliability is consistency: repeated trials give the same result. Validity is accuracy: the study truly measures what it claims to. A result can be reliably wrong, so adding trials improves reliability but never fixes a flawed design.

Two variables can move together because of a hidden third variable or pure coincidence. Only a controlled experiment that manipulates the independent variable while holding everything else constant can support a claim that one thing causes another.

In a direct relationship both variables move the same way, such as more fertilizer producing more growth, and the graph slopes upward. In an inverse relationship one rises as the other falls, such as pressure and gas volume, and the graph slopes downward.

The independent variable is what the researcher deliberately changes; the dependent variable is the outcome measured in response. On a graph the independent variable goes on the x-axis and the dependent variable on the y-axis.

The control group gets no treatment, or a placebo, and provides the comparison baseline. Controlled variables are the factors deliberately held constant for every group. Without both, a difference in results cannot be credited to the independent variable.

Observe and ask a question, research, form a testable hypothesis, run a controlled experiment, collect and analyze the data, then draw a conclusion and communicate it. A result that disproves the hypothesis is still valid and useful, not a failed experiment.