TEAS Science Practice Test 1

Question 1

The function of this prokaryotic organelle is to house the genes that code for the proteins needed by the cell.

A. Flagella
B. Ribosome
C. Nucleoid
D. Cell wall

Answer 1

C. Nucleoid. The Nucleoid is the nonmembrane-bound single circular chromosome, or circular DNA molecule of prokaryotic cells. It contains the genes that code for the proteins needed by the cells.

Question 2

Which of the following structures normally appears in pairs in the female reproductive system?

A. Cervix
B. Oviduct
C. Ovum
D. Uterus

Answer 2

B. Oviduct. The oviduct known as the fallopian tube, Carrie’s eggs from an ovary to the uterus. There are two oviducts, one for each ovary.

Question 3

Conducting cells in the heart are found in the

A. Purkinje fibers
B. Aortic valve
C. Pericardium
D. Chordae tendineae

Answer 3

A. Purkinje fibers. These fibers are the final branches of the cardiac conduction system. They conduct electrical impulses from the pacemaker cells of the heart to the cardiac muscle cells, causing them to contract and the heart to beat.

Question 4

What is the compact outlayer of bone called?

A. Cancellous
B. Cortical
C. Spongy
D. Tradecular

Answer 4

B. Cortical. The hard, compact outer layer of bone is known as cortical bone.

Question 5

Phytoplankton is added to a water-filled tank, and a bright light is shined into one end of the tank. The phytoplankton migrate to the side of the tank. Small fish are added to the tank, and they too migrate to the lit side of the tank. Researchers hypothesize that the fish migrate to the lit side to feed on the phytoplankton but are not actually attracted to the light itself. What control should the researchers use to confirm their hypothesis?

A. A tank with no phytoplankton, no fish, and no lit end.
B. A tank with no phytoplankton and no lit end but with fish.
C. A tank with no phytoplankton and no fish that is lit on one end.
D. A tank with no phytoplankton but with fish that is lit on one end.

Answer 5

D. A tank with no phytoplankton but with fish that is lit on one end.

Question 6

Which of the following actions is an example of an observation?

A. Measuring amount of rain that falls in a month on a city.
B. Calculating the relationship between speed and muscle mass.
C. Writing a report on a new planet discovered outside our solar system.
D. Proposing that longer grass is a better habitat for ticks than shorter grass.

Answer 6

A. Measuring amount of rain that falls in a month on a city.

Question 7

Which of the following organic molecules produces only water vapor (h2O) and carbon dioxide (CO2) when completely burned in the presence of oxygen (O2)?

A. Co2
B. CH3CI
C. C2H5OH
D. C2H5NH2

Answer 7

C. C2H5OH. Ethanol, C2H5OH, contains only carbon, oxygen, and hydrogen. When it reacts with oxygen as it burns, it will form only water vapor and carbon dioxide.

Question 8

Mendel’s law of independent assortment states that

A. The unit of inheritance is a distinct, independent quantity.
B. Offspring independently inherit one allele from each parent.
C. Alleles for one gene are independently sorted into gametes.
D. Alleles for two or more genes are independently sorted into gametes.

Answer 8

D. Alleles for two or more genes are independently sorted into gametes. The law of independent assortment basically states that each gene is inherited independently from the others; that is, the inheritance of one gene does not affect the inheritance of another. This happens because the alleles for two or more genes are independently sorted into gametes.

Question 9

Chemical messengers that can pass directly through the cell membrane without first binding to a receptor are part of which class of macromolecule?

A. Carbohydrates
B. Lipids
C. Nucleic acids
D. Proteins

Answer 9

B. Lipids. Chemical messengers that can pass directly through the cell of a membrane are steroid hormones, which are a type of lipid. Because the cell membrane is also made up of lipids, steroid hormones essentially “dissolve” in the membrane and pass right through.

Question 10

An individual with a dominant phenotype but unknown genotype for a single trait of of interest is mated to a recessive individual. The offspring are observed to determine the genotype of the dominant parent for that trait. This controlled mating is called a

A. Test cross
B. Dihybrid cross
C. F1 generation
D. Punnet square

Answer 10

A. Test cross. A test cross mates a dominant phenotype individual with a recessive individual to find out the genotype of the dominant individual. If the offspring all have the dominant phenotype, the the dominant parent is homozygous for the trait. If half of the offspring are recessive and the other half are dominant, then the dominant parent is heterozygous.

Question 11

In which of the following structures does the mechanical digestion of food begin?

A. Small intestine
B. Large intestine
C. Mouth
D. Stomach

Answer 11

C. Mouth. Mechanical digestion refers to the physical reduction of food into smaller pieces. This process begins in the mouth, where the teeth crush, grind, and tear food into smaller pieces. Chemical digestion starts here, too, as enzymes in saliva begin breaking down some of the chemicals in food.

Question 12

Which of the following glands is a part of the endocrine system ?

A. Adrenal
B. Lacrimal
C. Mammary
D. Salivary

Answer 12

A. Adrenal. Endocrine glands secrete hormones that act as chemical messengers within the body. The adrenal glands secrete several hormones, including epinephrine, norepinephrine, cortisol, and aldosterone.

Question 13

How does urine proceed through the excretory system?

Answer 13

1. Kidneys: urine moves from the kidneys into the
2. Ureters, which lead the urine to the
3. Urinary bladder.
4. The urine finally moves to the urethra for expulsion from the body.

Question 14

Which of the following structures helps to package a double-stranded length of DNA into a tightly compacted metaphase chromosome?

A. Centrosome
B. Chromatin
C. Histone
D. Gene

Answer 14

C. Histone. Histones are proteins that help wind DNA into a tightly packaged chromosome.

Question 15

In a reflex arc, which of the following structures is bypassed when a motor response is stimulated?

A. Brain
B. Spinal cord
C. Central nervous system
D. Peripheral nervous system

Answer 15

A. Brain. In a reflex arc, sensory input travels from the peripheral nervous system to the spinal cord, which processes the signal and then stimulates a motor neuron to affect a muscular action. The signal never travels to the brain, so the reflex is very fast.

Question 16

Which of the following represent the proper flow sequence of air through the respiratory system after it passes through the nose or mouth to the main bronchi?

A. Larynx 👉🏽 pharynx 👉🏽 trachea
B. Pharynx 👉🏽 larynx👉🏽 trachea
C. Trachea 👉🏽 larynx 👉🏽 pharynx
D. Pharynx 👉🏽 trachea 👉🏽 larynx

Answer 16

B. Pharynx 👉🏽 larynx👉🏽 trachea. The flow of air through the respiratory system from the nose or mouth to the main bronchi moves from the nose or mouth through the pharynx, larynx, and then the trachea.

Question 17

Which of the following strategies is the immune system’s first line of defense against pathogens?

A. Inflammatory response
B. Barrie’s against pathogens
C. Antibody-mediated immunity
D. Nonspecific attack by phagocytes

Answer 17

B. Barrie’s against pathogens. The body’s first line of defense against pathogens is to prevent them from entering the body at all. Barriers against the pathogens such as the skin, earwax, cilia (hairs lining the mucous membranes), and mucus trap or block pathogens before they enter the body.

Re: hence they always say never swallow mucus, spit it out.

Question 18

Unlike arteries, veins utilize which feature to prevent the back flow of blood?

A. High blood pressure
B. Low-oxygen blood
C. Thick walls
D. Valves

Answer 18

D. Valves. Valves inside veins prevent the back flow of blood. Arteries do not contain valves because the high pressure of the blood inside them prevents back flow.

Question 19

An acid catalyzed dehydration of a secondary alcohol

A. Yields the most substituted alkene in the absence of peroxides.
B. Yields the least substituted alkene in the absence of peroxides.
C. Occurs best with a nonpolar aprotic solvent.
D. Occurs best at a lower temperatures.

Answer 19

A. Yields the most substituted alkene in the absence of peroxides. When no peroxides are present, the acid catalyzed dehydration of a secondary alcohol generates the most substituted alkene.

Question 20

Which of the following is considered an accessory organ of the digestive system?

A. Liver
B. Colon
C. Stomach
D. Esophagus

Answer 20

A. Liver. Accessory organs of the digestive system are those that are involved in the digestion of food but are not part of the digestive tract. The liver secretes bile, which helps break up fats into tiny globules that can be more easily digested.

Question 21

Which of the following terms describes the attachment site that moves when a muscle contracts?

A. Action
B. Innervation
C. Insertion
D. Orgin

Answer 21

C. Insertion. The insertion of a muscle is the attachment site that moves when the muscle contracts. It is usually father away from the center of the body than the other end of the muscle, so it is also called the distal attachment of a muscle.

Question 22

The testes are located in an external pouch for which of the following reasons ?

A. The external pouch provides the testes with greater protection from external forces.
B. Sperm can only develop properly at temperatures slightly lower than normal body temperature.
C. From an external pouch, the sperm have a shorter distance to travel before reaching an egg.
D. Speak requires slightly higher temperatures than normal body temperature to properly develop.

Answer 22

B. Sperm can only develop properly at temperatures slightly lower than normal body temperature. Sperm is produced in the testes. Sperm requires slightly lower temperatures than normal body temperature to develop properly. Being located in an external pouch puts the testes at a slightly lower temperature than the rest of the body.

Question 23

Which of the following structures typically expels it’s secretions directly onto the surface of the skin?

A. Sebaceous gland
B. Meissner corpuscle
C. Eccrine sweat gland
D. Apocrine sweat gland

Answer 23

C. Eccrine sweat gland. These sweat glands open directly onto the surface of the skin and deposit sweat there.

Question 24

What structures are found in the plant cell but not in the animal cell?

A. Cell membrane
B. Cell wall
C. Chloroplasts
D. Large vacuole
E. Mitochondria
F. Nucleus

Answer 24

B. Cell wall
C. Chloroplasts
D. Large vacuole

Animal cells do not contain a cell wall.

Question 25

The equation for photosynthesis is shown as:

                                                            6CO2+6H2O+Energy 👉🏽 C6H12O6+6O2

Which of the following of these correctly identifies the reactants in the equation?

A. Glucose, oxygen
B. Carbon dioxide, water
C. Oxygen, carbon dioxide
D. Oxygen, water, glucose

Answer 25

B. Carbon dioxide, water. Carbon dioxide combines with water in the presence of energy. These reactants produce glucose in addition to oxygen as a waste material.

Question 26

When enough energy is added to a liquid to overcome the attractive forces between its molecules, the liquid undergoes

A. Melting
B. Condensation
C. Freezing
D. Vaporization

Answer 26

D. Vaporization. When enough energy is added to a liquid to overcome the attractive forces between its molecules, the liquid turns into gas. This process is call vaporization.

Question 27

Which of the following would best represent the process of respiration in the carbon cycle?

A. Decomposers breaking down dead animals
B. A cow eating grass
C. A plant absorbing carbon dioxide
D. A human exhaling carbon dioxide

Answer 27

D. A human exhaling carbon dioxide. Humans breathe out carbon dioxide during the process of respiration. Respiration returns carbon to the atmosphere from the biosphere.

Question 28

Unlike fully quadrupedal animals, the ventral surface of a bipedal human is on which side of the body?

A. Anterior
B. Cranial
C. Dorsal
D. Posterior

Answer 28

A. Anterior. The ventral surface is the abdominal surface of the body in both bipedal humans and quadrupedal animals like dogs. However, in humans, the abdominal surface of the body is also the anterior, or front, side of the body. In quadrupedal animals, the ventral surfaces faces the ground while the anterior surface is toward the head.

Question 29

Why are penicillin and it’s derivatives ineffective against pneumonia caused by bacteria in the genus Mycoplasma?

A. Mycoplasma are gram-negative bacteria and do not have a thick layer of peptidoglycan in their cell walls
B. Mycoplasma do not have a cell wall
C. Mycoplasma produce a capsule that is impenetrable to antibiotics
D. Mycoplasma is a fungus, and penicillin and it’s derivatives do not kill fungus

Answer 29

B. Mycoplasma do not have a cell wall. Penicillin and it’s derivatives are ineffective against mycoplasma because the latter do not have a cell wall. Penicillins and cephalosporins kill the cell wall by stopping the formation of peptidoglycan (pg). However, they kill only gram-positive bacteria with their thick layer of PG and are of no use on mycoplasma, which has no cell wall.

Question 30

An atom with 11 protons, 12 neutrons, and 10 electrons is

A. An uncharged atom.
B. A radioactive isotope.
C. A negatively charged ion.
D. A positively charged ion.

Answer 30

D. A positively charged ion. This atom has fewer electrons than protons, so it’s positive charges are not balanced out by it’s negative charges. Therefore, it is a positively charged ion.

Question 31

When neurotransmitters leave the axon terminal, to what location are they first released?

A. Membrane receptors
B. Synaptic cleft
C. Transmitting neuron
D. Receiving neuron

Answer 31

B. Synaptic cleft. Neurotransmitters are first released into the synaptic cleft by the transmitting neuron, or presynaptic neuron. The synaptic cleft is the small space between the axon terminal of the transmitting neuron and the dendrites of the receiving neuron (postsynaptic neuron).

Question 32

Low-oxygen areas in the oceans where almost no life can survive, or “dead zones,” can form when agricultural fertilizers wash into the water and cause massive overgrowth of algae. When the algae die, their decomposition removes oxygen from the water. Every summer (but not other times of the year), a huge dead zone forms in the Gulf of Mexico at the mouth of the Mississippi River. Scientists studying this phenomenon are most likely to agree with which of the following statements about the cause of the dead zone?

A. Fertilizers are washed into the Gulf of Mexico during the winter by the Mississippi River.
B. Massive amounts of algae are constantly carried into the Gulf of Mexico by the Mississippi River.
C. Fertilizers from spring planting are washed into the Gulf of Mexico by the Mississippi River.
D. Oxygen is constantly being removed from the Gulf of Mexico by the action of the Mississippi River.

Answer 32

C. Fertilizers from spring planting are washed into the Gulf of Mexico by the Mississippi River. The dead zone in the Gulf of Mexico is caused by fertilizer washing into the water. If this is happening at the mouth of the Mississippi River, it is likely that the Mississippi River is carrying the fertilizer to the gulf. The fact that it is happening in the summer makes sense because farmers apply fertilizers to their fields I. The spring, when they plant their crops. It takes time for the fertilizer to be carried to the Gulf and cause the algae to grow and then for the algae to decay and deplete the water of oxygen.

Question 33

Which of the following is most likely to be a source of error when using a spectrophotometer?

A. Measuring a solution of unknown concentration
B. Touching the flat sides of the sample holder
C. Analyzing a solution that has a visible color
D. Using a solution that is clear and colorless to the naked eye

Answer 33

B. Touching the flat sides of the sample holder. Touching the flag sides of the sample holder (also known as the cuvette) can leave fingerprints that can interfere with the spectrophotometer measurements. A light beam is shined through the sample holder, so any debris on the sample holder can scatter the light and cause inaccurate measurements.

Question 34

Acetic acid is a weak acid that dissociates according to the following equation:
CH3COOH ➡️⬅️ CH3COO-+ H+

A student prepares an acetic acid solution and tests the pH (labeled pH1) and Keq (labeled k2). Which of the following best describes the change observed?

A. pH2 >pH1
B. pH1 >pH2
C. K2 >k1
D. K1 >K2

Answer 34

A. pH2 >pH1. The addition of sodium acetate to an acetic acid solution causes an overall increase in the number of acetate ions in solution. According to LeChatlier’s principle, this will push the equilibrium to the left, leading to a decrease in the number of protons in a solution and, consequently, an increase in the pH. The Keq of the faction and the Ka of acetic acid must remain constant, so an increase in the concentration of one product must be accompanied by a decrease in the concentration of the other product in order to maintain the equilibrium constant.

Question 35

How do cytotoxic T cells differ from helper T cells?

A. Cytotoxic T cells mature in the thymus, while helper T cells mature in the bone marrow.
B. Helper T cells mature in the thymus, while cytotoxic T cells mature in the bone marrow.
C. Cytotoxic T cells directly destroy infected or abnormal cells, while helper T cells do not.
D. Helper T cells directly destroy infected or abnormal cells, while cytotoxic T cells do not.

Answer 35

C. Cytotoxic T cells directly destroy infected or abnormal cells, while helper T cells do not. Cytotoxic T cells bind to infected or abnormal cells of the body and release proteins that destroy those cells.

Question 36

If a heterozygous blood type A female is crossed with a heterozygous blood type B male, what is the probability of producing a child with type AB blood?

Answer 36

25%. “Mendel’s law of inheritance”

Question 37

HCI + NaOH
Which of the following is a product of the reaction above?

A. Water
B. Sodium hydroxide
C. Chlorine gas
D. Hydrogen gas

Answer 37

A. Water. The strong acid (hydrogen chloride) and strong base (sodium hydroxide) neutralize to form water and sodium chloride salt.

Question 38

Which of the following organelles in eukaryotic cells is responsible for the production of adenosine triphosphate (ATP)?

A. Vesicles
B. Cytoskeleton
C. Peroxisome
D. Mitochondria

Answer 38

D. Mitochondria. These are double membrane-bound, rod-shaped organelles in the cytoplasm that have their own DNA and ribosomes and can replicate to create new mitochondria. Mitochondria function during cellular respiration to produce ATP, the energy supply molecule for life processes. This why they are often referred to as the powerhouse of the cell.

Question 39

Alexander Fleming famously discovered penicillin by accident when mold spores contaminated one of the Petri dishes in which he was growing bacterial colonies. How did he infer that the mold was secreting a substance that could kill bacteria?

A. The mold colony was a different color than the bacteria colonies.
B. All of the bacterial colonies in the petri had died.
C. Only the bacteria immediately surrounding the mold colony had died.
D. All of the mold colonies in the Petri dish had died.

Answer 39

C. Only the bacteria immediately surrounding the mold colony had died. Fleming found that only the bacteria next to the mold colony has died, leaving a cleared ring around the mold colony. He concluded that the mold was secreting a substance that could kill the bacteria nearby. He called this substance penicillin.

Question 40

Almost all of the weight of a carbon atom come from which of these particles?

A. Protons only
B. Neutrons and electrons
C. Protons and neutrons
D. Protons, electrons, and neutrons

Answer 40

C. Protons and neutrons. Almost all of the weight of an atom comes from the protons and neutrons in its nucleus. Neutrons weigh approximately 1 atomic mass unit, and protons weigh 1 atomic mass unit (1.67x10^-24 grams).