ATI TEAS 7 — All Questions

Which gland is often called the 'master gland' because it directs several other endocrine glands?

• a.The adrenal gland
• b.The pineal gland
• c.The pituitary gland✓
• d.The thyroid gland

The pituitary releases hormones that regulate the thyroid, adrenal cortex, and gonads, though it is itself directed by the hypothalamus. The thyroid and adrenal glands are among the targets it controls, and the pineal gland mainly secretes melatonin.

Which hormone raises blood glucose when levels fall between meals?

• a.Aldosterone
• b.Glucagon✓
• c.Calcitonin
• d.Insulin

Glucagon, released by pancreatic alpha cells, signals the liver to break down glycogen and release glucose. Insulin does the opposite by lowering blood glucose, calcitonin lowers blood calcium, and aldosterone regulates sodium.

The thyroid gland requires which dietary element to make its hormones?

• a.Phosphorus
• b.Iodine✓
• c.Magnesium
• d.Calcium

Thyroid hormones are built around iodine atoms, which is why deficiency can enlarge the gland. Calcium, magnesium, and phosphorus have important roles elsewhere but are not incorporated into thyroid hormone.

Most hormone systems in the body are controlled by which kind of regulation?

• a.Positive feedback
• b.Random secretion
• c.Negative feedback✓
• d.Continuous maximum output

In negative feedback, the response reduces the original stimulus, holding the variable near a set point. Positive feedback amplifies a change and is rare, used in events such as labor contractions, while random or maximal secretion would make regulation impossible.

Which gland releases epinephrine during a stressful event?

• a.The thymus
• b.The adrenal gland✓
• c.The parathyroid gland
• d.The salivary gland

The adrenal medulla secretes epinephrine, raising heart rate and blood glucose. The thymus matures T cells, the parathyroid glands regulate calcium, and salivary glands produce saliva.

Which cells produce antibodies during an adaptive immune response?

• a.Red blood cells
• b.Cytotoxic T lymphocytes
• c.B lymphocytes✓
• d.Platelets

B lymphocytes mature into plasma cells that secrete antibodies against a specific antigen. Cytotoxic T cells kill infected cells directly rather than secreting antibodies, and red cells and platelets have no role in antibody production.

What is an antigen?

• a.A protein the body makes to neutralize a pathogen
• b.A cell that engulfs and digests invading bacteria
• c.A substance recognized as foreign by the immune system✓
• d.A chemical that raises the body's temperature

An antigen is the foreign marker the immune system detects and responds to. The protein made to neutralize it is an antibody, the engulfing cell is a phagocyte, and a temperature-raising chemical is a pyrogen.

How does a vaccine protect a person from a disease?

• a.It permanently raises the body's core temperature
• b.It supplies antibodies borrowed from another person
• c.It prompts the immune system to form memory cells✓
• d.It kills any pathogen already present in the blood

A vaccine exposes the immune system to a harmless form of an antigen so memory cells can respond quickly to a later infection. Receiving ready-made antibodies is passive immunization rather than vaccination, and vaccines neither sterilize the blood nor change body temperature.

Which response is part of nonspecific, innate immunity rather than adaptive immunity?

• a.Recognizing a previously encountered antigen
• b.Inflammation at the site of a wound✓
• c.Producing antibodies against a specific virus
• d.Forming memory cells after an infection

Inflammation occurs the same way no matter what the invader is, which makes it innate. Antibody production, memory cell formation, and antigen recognition all target a particular pathogen and therefore belong to adaptive immunity.

Which layer of the skin contains blood vessels, nerve endings, sweat glands, and hair follicles?

• a.The stratum corneum
• b.The dermis✓
• c.The epidermis
• d.The subcutaneous fat layer

The dermis is the thick middle layer holding vessels, nerves, glands, and follicles. The epidermis and its outermost stratum corneum have no blood supply of their own, and the subcutaneous layer beneath is mostly fat and loose connective tissue.

What is the main protective role of melanin in the skin?

• a.It insulates the body against heat loss
• b.It absorbs ultraviolet radiation from sunlight✓
• c.It fights bacteria that land on the skin
• d.It waterproofs the surface of the skin

Melanin pigment absorbs ultraviolet light and limits damage to the DNA of skin cells. Waterproofing comes largely from keratin and oils, insulation comes from subcutaneous fat, and antibacterial defense comes from the skin's acidic secretions.

In a typical pregnancy, where does fertilization of the egg normally occur?

• a.In the fallopian tube✓
• b.In the uterus
• c.In the ovary
• d.In the cervix

Sperm normally meet the egg in the fallopian tube, and the fertilized egg then travels to the uterus to implant. The ovary releases the egg, the uterus receives the embryo afterward, and the cervix is the passage into the uterus.

The cell membrane is described as selectively permeable. What does this mean?

• a.It blocks every substance from entering or leaving the cell
• b.It allows anything dissolved in water to pass freely
• c.It allows some substances to cross while restricting others✓
• d.It dissolves whenever the cell is placed into water

A selectively permeable membrane controls which molecules cross, letting small nonpolar substances pass while regulating ions and large molecules. Blocking everything would starve the cell, free passage of all solutes would eliminate control, and the membrane does not dissolve in water.

Which organelle assembles amino acids into proteins?

• a.The ribosome✓
• b.The Golgi apparatus
• c.The lysosome
• d.The nucleolus

Ribosomes read messenger RNA and link amino acids into polypeptide chains. The Golgi apparatus modifies and packages proteins after they are made, lysosomes digest waste, and the nucleolus builds ribosome subunits rather than proteins.

Which structure is found in a plant cell but NOT in an animal cell?

• a.A cell membrane
• b.A nucleus
• c.Mitochondria
• d.A cell wall✓

Plant cells are enclosed by a rigid cellulose wall outside the membrane, which animal cells lack. Membranes, nuclei, and mitochondria are present in both types of eukaryotic cell.

Which organelle contains digestive enzymes that break down worn-out cell parts?

• a.The lysosome✓
• b.The rough endoplasmic reticulum
• c.The centriole
• d.The Golgi apparatus

Lysosomes hold hydrolytic enzymes that dismantle damaged organelles and engulfed material. The rough endoplasmic reticulum makes proteins, centrioles organize the spindle during division, and the Golgi apparatus sorts and ships products.

Which macromolecule is built from a chain of amino acids?

• a.A lipid
• b.A carbohydrate
• c.A nucleic acid
• d.A protein✓

Amino acids joined by peptide bonds form proteins. Carbohydrates are chains of sugars, lipids are built from fatty acids and glycerol, and nucleic acids are chains of nucleotides.

A red blood cell placed in pure distilled water will most likely:

• a.Swell as water moves into the cell✓
• b.Shrink as water leaves the cell
• c.Lose its nucleus into the water
• d.Stay exactly the same size

Distilled water is hypotonic to the cell's interior, so water moves in by osmosis and the cell swells and may burst. Shrinking happens in a hypertonic solution, and mature red blood cells have no nucleus to lose.

Which transport process requires the cell to spend energy?

• a.Active transport against a gradient✓
• b.Facilitated diffusion through a channel
• c.Osmosis of water across a membrane
• d.Simple diffusion of small molecules

Moving a substance from lower to higher concentration works against the gradient and requires ATP. Simple diffusion, osmosis, and facilitated diffusion all follow the gradient and are therefore passive.

In DNA, the base adenine always pairs with which other base?

• a.Cytosine
• b.Uracil
• c.Guanine
• d.Thymine✓

Complementary base pairing in DNA joins adenine to thymine and guanine to cytosine. Uracil replaces thymine only in RNA, so it is not a DNA pairing partner.

Which statement correctly distinguishes RNA from DNA?

• a.RNA contains no sugar while DNA contains ribose
• b.RNA is double-stranded while DNA is single-stranded
• c.RNA contains uracil while DNA contains thymine✓
• d.RNA is found only outside cells while DNA is inside

Uracil replaces thymine in RNA, and RNA also carries ribose rather than deoxyribose. RNA is typically single-stranded while DNA is a double helix, RNA is found inside cells, and both molecules contain a sugar.

What is the result of meiosis in humans?

• a.Two identical cells with 46 chromosomes each
• b.Two cells that are genetically identical clones
• c.Four cells with 23 chromosomes each✓
• d.One cell with 92 chromosomes

Meiosis halves the chromosome number and produces four genetically varied gametes with 23 chromosomes. Mitosis is what yields two identical 46-chromosome cells, and no normal human cell division produces a 92-chromosome cell.

An organism's observable physical traits are called its:

• a.Genotype
• b.Allele
• c.Karyotype
• d.Phenotype✓

Phenotype is what can be observed, such as eye color or height. Genotype is the underlying combination of alleles, a karyotype is a picture of the chromosomes, and an allele is one version of a single gene.

Two parents are each heterozygous for a trait (Aa). What fraction of their offspring is expected to show the recessive trait?

• a.One quarter✓
• b.One half
• c.None of them
• d.Three quarters

A Punnett square for Aa x Aa gives AA, Aa, Aa, and aa, so only the one aa offspring in four shows the recessive trait. Three quarters show the dominant trait, and one half is the fraction that is heterozygous.

Which equation summarizes aerobic cellular respiration?

• a.Glucose alone yields oxygen and lactic acid
• b.Carbon dioxide plus water yields glucose plus oxygen
• c.Glucose plus oxygen yields carbon dioxide, water, and ATP✓
• d.Water plus sunlight yields glucose and carbon dioxide

Cells oxidize glucose with oxygen to release energy, giving off carbon dioxide and water. The choices that start from carbon dioxide, or from water and sunlight, describe photosynthesis or a garbled version of it, and lactic acid forms only in anaerobic conditions without producing oxygen.

What happens to an enzyme when it is exposed to high heat or extreme pH?

• a.It doubles the number of active sites it has
• b.It denatures and loses its functional shape✓
• c.It becomes permanently faster at its reaction
• d.It is converted into a carbohydrate

Enzymes are proteins whose activity depends on a precise three-dimensional shape, and harsh conditions unfold that shape so the substrate no longer fits. Enzymes do not gain speed, change into other macromolecules, or add active sites under stress.

Which subatomic particle determines the identity of an element?

• a.The neutron
• b.The positron
• c.The proton✓
• d.The electron

The number of protons is the atomic number and defines which element an atom is. Changing neutrons produces an isotope of the same element, changing electrons produces an ion, and positrons are not part of a stable atom.

An atom's mass number is calculated by adding which two values?

• a.Protons and neutrons✓
• b.Electrons and neutrons
• c.Neutrons and valence electrons
• d.Protons and electrons

Mass number counts the particles in the nucleus, which are the protons and neutrons. Electrons have so little mass that they are not included in the total.

What happens to electrons when an ionic bond forms between two atoms?

• a.They are transferred from one atom to the other✓
• b.They are destroyed and converted into energy
• c.They orbit both nuclei in a single shared shell
• d.They are shared equally between the two atoms

In an ionic bond one atom gives up electrons and the other accepts them, producing oppositely charged ions that attract. Equal sharing describes a nonpolar covalent bond, and electrons are never destroyed in chemical bonding.

A solution has a pH of 4. How does it compare to a solution with a pH of 6?

• a.It is slightly more basic
• b.It is twice as acidic
• c.It is 100 times more acidic✓
• d.It is exactly the same acidity

The pH scale is logarithmic, so each whole unit is a tenfold change in hydrogen ion concentration and two units is ten times ten. A lower pH means more acidic, not more basic, and the difference is far larger than double.

In a saltwater solution, which component is the solvent?

• a.The salt
• b.The water✓
• c.The dissolved ions
• d.The container

The solvent is the substance present in greater amount that does the dissolving, which is water here. Salt is the solute, the ions are what the solute becomes, and the container plays no chemical role.

According to the law of conservation of mass, in a closed chemical reaction the total mass of the products is:

• a.Always greater than the mass of the reactants
• b.Equal to the total mass of the reactants✓
• c.Always less than the mass of the reactants
• d.Unrelated to the mass of the reactants

Atoms are rearranged rather than created or destroyed, so mass is conserved in a closed system. Any gain or loss observed in an open container reflects gas escaping or entering rather than a change in total mass.

Which change of state describes a gas becoming a liquid?

• a.Sublimation
• b.Melting
• c.Evaporation
• d.Condensation✓

Condensation is the transition from gas to liquid, as when water droplets form on a cold glass. Evaporation runs the other direction, melting turns a solid to a liquid, and sublimation takes a solid straight to a gas.

What does a catalyst do in a chemical reaction?

• a.It changes the products the reaction will make
• b.It is consumed and must be replaced each time
• c.It raises the energy needed to start the reaction
• d.It speeds the reaction by lowering activation energy✓

A catalyst provides an easier pathway with lower activation energy and emerges unchanged at the end. It does not alter what products form, is not used up, and lowers rather than raises the energy barrier.

A researcher tests whether a fertilizer increases plant height. What is the dependent variable?

• a.The height of the plants✓
• b.The amount of fertilizer applied
• c.The type of soil used in each pot
• d.The number of hours of daylight

The dependent variable is the outcome measured in response to the treatment, which is plant height. The fertilizer amount is the independent variable, and soil type and daylight are constants that should be held the same.

Why do scientists repeat an experiment several times before accepting a result?

• a.Repeating shortens the time the experiment requires
• b.Repeating reduces the influence of chance on the result✓
• c.Repeating makes the measuring instruments more precise
• d.Repeating guarantees the hypothesis will be proved

Replication shows whether an outcome is consistent or was a fluke of a single trial. Repetition cannot prove a hypothesis, does not improve the instruments themselves, and generally takes more time rather than less.

How does a scientific theory differ from a hypothesis?

• a.A theory cannot be tested while a hypothesis can
• b.A theory applies to one experiment at a time
• c.A theory is a guess while a hypothesis is proven
• d.A theory is supported by a large body of evidence✓

A theory is a broad explanation that has survived extensive testing, while a hypothesis is a specific testable prediction. Calling a theory a guess reverses the two, and theories remain testable and explain many observations rather than one.

Which instrument would a student use to measure the volume of a liquid most precisely?

• a.A graduated cylinder✓
• b.A thermometer
• c.A triple-beam balance
• d.A metric ruler

A graduated cylinder is marked in milliliters and is read at the bottom of the meniscus. A balance measures mass, a ruler measures length, and a thermometer measures temperature.

How many milligrams are in one gram?

• a.1,000✓
• b.1,000,000
• c.100
• d.10

The prefix milli means one thousandth, so a gram contains 1,000 milligrams. One hundred would match centigrams, ten is far too few, and a million milligrams would equal a kilogram.

Choose the correct word: "The new medication had a noticeable ___ on her blood pressure."

• a.affected
• b.effect✓
• c.effecting
• d.affect

The blank needs a noun meaning result, and 'effect' is the noun while 'affect' is normally the verb meaning to influence. The two participle forms cannot follow the article 'a' in this position.

Which sentence uses 'it's' correctly?

• a.The dog wagged it's tail at the visitor.
• b.The clinic moved it's office to the second floor last year.
• c.It's already too late to reschedule the appointment.✓
• d.Every policy has it's own exceptions.

The apostrophe form is only ever a contraction of 'it is' or 'it has', which is how it works in 'It's already too late'. The other three sentences call for the possessive 'its', which takes no apostrophe.

Choose the correct word: "To ___ should I address this letter?"

• a.who's
• b.who
• c.whom✓
• d.whose

The pronoun follows the preposition 'to', so the objective form 'whom' is required. 'Who' is the subject form, 'whose' shows possession, and 'who's' is a contraction of 'who is'.

Choose the correct word: "There are ___ chairs in this waiting room than in the other one."

• a.lesser
• b.less
• c.least
• d.fewer✓

Chairs can be counted one by one, and countable nouns take 'fewer'. 'Less' is reserved for quantities measured in bulk, such as water or time, and the other two forms do not fit the comparison.

Choose the correct word: "The second draft was much clearer ___ the first."

• a.then
• b.than✓
• c.that
• d.thus

'Than' is the word used in comparisons, while 'then' refers to time or sequence. 'That' and 'thus' cannot complete a comparative phrase beginning with 'clearer'.

Which of the following is a sentence fragment?

• a.Rain fell all night.
• b.Although the results arrived on Friday afternoon.✓
• c.The nurse charted the vital signs.
• d.She arrived well before the clinic opened for the day.

A fragment lacks an independent clause, and 'Although' leaves the thought incomplete with no main clause to finish it. The other three each contain a subject and a verb that stand alone as complete statements.

Which sentence contains a comma splice?

• a.The lab closed early; we rescheduled the test.
• b.The lab closed early, we rescheduled the test.✓
• c.Because the lab closed early, we rescheduled the test.
• d.The lab closed early, so we rescheduled the test.

A comma splice joins two independent clauses with only a comma, which is what happens in 'The lab closed early, we rescheduled the test.' The other versions repair the join with a coordinating conjunction, a subordinating conjunction, or a semicolon.

Which sentence uses a colon correctly?

• a.She packed: a jacket and an umbrella for the trip.
• b.Bring with you: identification and insurance.
• c.The kit contains three items: gauze, tape, and scissors.✓
• d.The kit contains: gauze, tape, and scissors.

A colon follows a complete independent clause before introducing a list, and only 'The kit contains three items' is such a clause. Putting the colon straight after a verb such as 'contains' or 'packed', or after the phrase 'Bring with you', interrupts a construction that is not yet complete.

Which sentence is punctuated correctly?

• a.After the shift, ended the nurse completed her notes.
• b.After the shift ended the nurse completed her notes.
• c.After, the shift ended the nurse completed her notes.
• d.After the shift ended, the nurse completed her notes.✓

An introductory dependent clause is followed by a comma before the main clause, as in 'After the shift ended, the nurse completed her notes.' One version omits that comma entirely, and the others drop it into the middle of the clause, breaking the sentence apart.

Choose the correct verb: "The box of surgical supplies ___ on the counter."

• a.have been
• b.is✓
• c.were
• d.are

The subject is 'box', which is singular; 'of surgical supplies' is a prepositional phrase and cannot change the subject. Plural verbs agree with 'supplies' rather than with the true subject of the sentence.

Which sentence shows correct agreement between a collective noun and its pronoun?

• a.The committee published its report on Monday.✓
• b.The committee published their report on Monday.
• c.The committee have published their report on Monday.
• d.The committee publishes their report on Monday.

In American usage a collective noun acting as a single unit takes a singular verb and the singular pronoun 'its'. The other versions pair the singular noun with the plural 'their' or with a plural verb.