A&P EXAM 1-Mastering A&P

Which of the following processes allows cells to concentrate material that is present only in very small amounts in the extracellular fluid?

receptor-mediated endocytosis (Receptor-mediated endocytosis is the main mechanism for the specific endocytosis and transcytosis of most macromolecules by body cells, and it is exquisitely selective. The mechanism also allows cells to concentrate material that is present only in very small amounts in the extracellular fluid)

What is the primary energy-transferring molecule in cells?

ATP; When broken (hydrolyzed), the high-energy phosphate bonds in the ATP molecule release the energy used to do cellular work.

What is the difference between active and passive transport across the plasma membrane?

Active transport is ATP dependent, whereas passive transport uses only the kinetic energy of the particles for movement across the plasma membrane. (In active transport, the cell provides the metabolic energy (ATP) needed to move substances across the plasma membrane (against their concentration gradient). In passive transport, substances cross the plasma membrane (down their concentration gradient) using kinetic energy, without any energy input from the cell.)

T/F When an acid is added to a solution containing a weak base, the weak base will buffer the drop in pH by completely dissociating and accepting all of the hydrogen ions released from the acid.

False: Buffers resist abrupt and large swings in the pH of body fluids by releasing hydrogen ions (acting as acids) when the pH begins to rise and by binding hydrogen ions (acting as bases) when the pH drops. Buffers can do this because they consist of a combination of a weak acid and a corresponding weak base. Weak acids and bases dissociate (ionize) partially and reversibly, whereas strong acids and bases dissociate completely and irreversibly.

T/F In a solution, the solute is the substance present in the greatest amount.

False: In a solution, the solute is the substance present in lesser amounts. There may be many solutes.

T/F Cells within the body work independently of one another and rarely have direct effects on other cells.

False; cells work together

Which of the following statements most accurately describes the complementarity of anatomy and physiology?

Functions occur because of the anatomy that exists within the body.

What is the diffrence between isotonic, hypertonic, and hypertonic solutions with the movement of water?

Isotonic- water moves in and out hypertonic- water moves out hypotonic- water moves in

Which of the following best defines anatomy?

It is the study of the structure of body parts and their relationships with one another.

What is the difference between kinetic and potential energy?

Kinetic energy is energy in action, while potential energy is stored energy.

Which of the following statements is true regarding the reaction without an enzyme compared to the one with an enzyme? a. The reaction in the presence of enzyme releases more energy. b. The reaction in the presence of enzyme will form a larger proportion of product. c. Less energy input is required to start the reaction in the presence of enzyme. d. All of the listed responses are true.

Less energy input is required to start the reaction in the presence of enzyme. Enzyme-catalyzed reactions require less activation energy and therefore are initiated with a lower input of energy. This activation energy represents the energy necessary for driving the early stages of the reaction: creating contact between properly oriented substrates, breaking original bonds, and so on.

Assume that Na+ is being transported across a membrane via facilitated diffusion. Which of the following conditions would allow for the most transport of Na+ across that membrane?

Na+ diffusing toward the side of the membrane with Cl− and 50% less Na+ (A larger concentration gradient will provide greater kinetic energy to drive diffusion and Na+ will be electrically attracted to the Cl−; this will create a large electrochemical gradient.)

What explains the negative charge on the oxygen atom within the water molecule?

Oxygen atoms have a stronger pull on the electrons shared within a covalent bond formed between oxygen and hydrogen. Oxygen atoms are highly electronegative and pull electrons away from the electropositive hydrogen atom. Also, the nonbonding (lone) electron pairs on the oxygen, which are responsible for bending the molecule, are negative.

What does a phospholipid molecule look like?

Phospholipids consist of a glycerol backbone linked to two fatty acid chains and a phosphorus-containing group.

What can we infer if we see a large number of mitochondria in a cell?

The cell has a great metabolic demand. (Mitochondria are threadlike or lozenge-shaped membranous organelles. In living cells they squirm, elongate, and change shape almost continuously. They are the power plants of a cell, providing most of its ATP supply.)

What is transcription?

Transcription is the synthesis of RNA using DNA as a template.

What does a phospholipid and a triglyceride molecule look like? And what are they considered as?

Triglycerides and phospholipids are two of the three major types of lipids.Phospholipids consist of a glycerol backbone linked to two fatty acid chains and a phosphorus-containing group and triglycerides contains a glycerol backbone and linked to two fatty acid chains.

T/F In their resting state, all body cells exhibit a resting membrane potential; therefore, all cells are polarized.

True, (All cells have a resting membrane potential (RMP), such that the inside (interior surface) of the cell membrane has a net negative charge while the outside (external surface) of the membrane has a net positive charge. Given the different (opposite) charges on either side of the cell membrane, the cell is considered to be polarized. This RMP, which results from separation of charged particles (ions) across the cell membrane, can be measured in millivolts (typically ranging from −50 to −90 mV depending on the cell type).)

T/F The major function of DNA is to provide the genetic instructions for protein synthesis.

True: DNA provides the basic instructions for building every protein in the body. RNA carries out the orders for protein synthesis issued by DNA.

What is a membrane potential?

a voltage or electrical charge across the plasma membrane (The membrane potential is the electrical potential energy (measured in millivolts) resulting from the separation of oppositely charged ions across the plasma membrane. At rest, membrane potentials are typically negative, ranging from − 50 to minus 100 mV, with more anions (than cations) concentrated along the internal surface of the membrane, and more cations (than anions) concentrated along the external surface.)

Which of the following statements regarding atoms is true? a. The reactivity of an atom is based on the number of electrons in its outer valance shell. b. The chemical reactivity of an atom is based on the overall number of electrons in the atom. c. Atomic weight is determined by the number of electrons in an atom of a given element. d. Atomic weight is determined by the number of protons in an atom of a given element.

a. The reactivity of an atom is based on the number of electrons in its outer valance shell.

The pH scale __________. a. is based on the concentration of hydrogen ions in a solution b. is based on the salinity of a solution c. is linear d. ranges from 1 to 7

a. is based on the concentration of hydrogen ions in a solution; The pH scale, which ranges from 0 to 14, is a logarithmic scale based on the concentration of hydrogen ions in a solution.

Which of the following organelles is correctly paired with its function? a. smooth endoplasmic reticulum: metabolism of lipids b. mitochondrion: packaging proteins and lipids c. Golgi apparatus: produce energy for the cell d. lysosome: protein synthesis

a. smooth endoplasmic reticulum: metabolism of lipids (The smooth ER also plays a role in synthesizing steroid hormones, absorbing and transporting fats, detoxifying toxins, and breaking down glycogen.)

What is the classification of a solution of NaOH with a pH of 8.3? a. acidic solution b. alkaline solution c. neutral solution d. buffered solution

alkaline solution; A pH between 0.0 and 7.0 is acidic. A pH between 7.0 and 14.0 is basic. Therefore, a solution with a pH of 8.3 is an alkaline (or basic) solution. NaOH is an example of a basic compound.

Which of the following statements about the polarity of covalent bonds is correct? a. Nonpolar molecules have partial charges which can lead to hydrogen bonding. b. Small atoms with 6 or 7 valence shell electrons tend to be electronegative. c. The atoms of a polar molecule share electrons equally. Polar covalent bonds involve the transfer of electrons from electropositive atoms to electronegative atoms.

b. Small atoms with 6 or 7 valence shell electrons tend to be electronegative. Small atoms with 6 or 7 valence shell electrons, such as oxygen, nitrogen, and chlorine, are electron-hungry. They attract electrons very strongly, a capability called electronegativity.

Which of the following is a FALSE statement about carbohydrates? a. Glycogen is a complex carbohydrate formed by dehydration synthesis of glucose molecules. b. The chemical composition of carbohydrates includes two oxygens and one hydrogen for every carbon present. c. Dietary glucose is primarily used to drive our metabolic pathways that produce energy. d. Carbohydrates consist of monomers called simple sugars.

b. The chemical composition of carbohydrates includes two oxygens and one hydrogen for every carbon present. (The correct ratio is two hydrogens and one oxygen for every carbon.)

All amino acids contain __________. a. an amine group and a fatty acid b. an amine group and an acid group c. phosphorus and nitrogen d. a nitrogen-containing base and a pentose sugar

b. an amine group and an acid group

What must happen before a body cell can begin mitotic cell division? a. Its DNA must be divided in half so that half can go to one daughter cell and half can go to the other daughter cell. b. The DNA is expelled from the cell so that it will not be affected by the division process. c. Its DNA must be replicated exactly so that identical copies of the cell's genes can be passed on to each of its offspring. d. The DNA undergoes mutation in order to produce genetically specialized cells.

c. Its DNA must be replicated exactly so that identical copies of the cell's genes can be passed on to each of its offspring.

Which of the following is NOT one of the three major types of chemical reactions? a. synthesis b. exchange c. hyperbolic d. decomposition

c. hyperbolic; Most chemical reactions exhibit one of three recognizable patterns. They are either synthesis, decomposition, or exchange reactions.

Which four elements comprise approximately 96% of our body weight?

carbon, oxygen, hydrogen, and nitrogen.

Ions are transported across plasma membranes using __________, which requires __________.

channel-mediated facilitated diffusion; kinetic energy. Ions travel through aqueous channels down their concentration gradients. Kinetic energy drives this process.

The levels of structural organization in the human body.

chemical level- cellular level- tissue level- organ level- organ system level- organism level

Which of the following names the three main parts of a human cell?

cytoplasm, plasma membrane, and nucleus

Which of the following statements is true? a. Exocytosis involves infolding of the plasma membrane. b. Unlike endocytosis, exocytosis does not rely on protein interactions with the plasma membranes. c. Endocytosis and exocytosis are passive transport mechanisms. d. During exocytosis, substances from inside the cell are moved outside.

d. During exocytosis, substances from inside the cell are moved outside. (Vesicular transport processes that eject substances from the cell interior into the extracellular fluid are called exocytosis. Exocytosis is a form of active transport; thus, it requires energy, usually in the form of ATP.)

Which of the following is an example of a decomposition reaction? a. MgSO4 + 2NaCl → MgCl2 + Na2SO4 b. 2Na + Cl2 → 2NaCl c. H2 + O2 → H2O d. MgO2 → Mg + O2

d. MgO2 → Mg + O2; A decomposition reaction occurs when a larger molecule is broken down into smaller molecules or its constituent atoms.

Water is an important molecule because it __________. a. is non-polar b. has a low heat capacity c. is a poor solvent since few things dissolve in it d. can form hydrogen bonds

d. can form hydrogen bonds; Because of its polar nature, water is able to form hydrogen bonds. In fact, many of the special properties of water derive from its extensive hydrogen bonding capacity. In addition, water has a high heat capacity and is considered a universal solvent since it dissolves more substances than any other known solvent.

When molecules or ions move from an area of high concentration to an area of lower concentration is is called_____________.

diffusion down a concentration gradient; Transport by diffusion of a molecule down its concentration gradient is a spontaneous process that requires no energy input.

What type of bond is formed between the oxygen atom of one water molecule and the hydrogen atom of another water molecule?

hydrogen bond, The attraction between the slightly negative oxygen atom of one molecule and the slightly positively charged hydrogen atom within a separate water molecule is the basis of hydrogen bond formation. It is a form of dipole-dipole interaction.

Which life process generates the raw materials and energy needed to sustain all other life processes?

metabolism

What is the function of the Golgi apparatus?

modification and packaging of proteins (This function is handled by the Golgi apparatus within the endomembrane system; it functions in the sorting and modifying of membrane-bound proteins being transported to various cellular locations.)

With regards to a set point or normal limit, negative feedback always __________ a physiological value to the set point or normal limit.

returns

Which organelle is responsible for synthesizing proteins?

ribosomes (Free ribosomes float freely in the cytoplasm and produce soluble proteins that function in the cytosol, as well as those imported into mitochondria and some other organelles. Fixed ribosomes, which stud the rough endoplasmic reticulum, synthesize proteins destined either for incorporation into the cell membrane or lysosomes, or for export from the cell.)

How would a small, nonpolar molecule likely diffuse across a cell membrane?

simple diffusion; Nonpolar (or lipid-soluble) molecules dissolve into the phospholipid regions of the cell membrane and will pass with no additional protein transporters required.

Homeostasis Balance

stimulus- receptor- input- control center- output-response

What major function occurs on the specific membranes indicated in the rough endoplasmic reticulum?

synthesis of proteins; proteins are synthesized on ribosomes bound to the rough ER before being modified and secreted or packaged.

What is t-RNA

tRNA Is a molecule that brings amino acids to the ribosome during translation. (Transfer RNA (tRNA) are small, roughly L-shaped molecules that ferry amino acids to the ribosomes. There they decode mRNA's message for the amino acid sequence of the polypeptide to be built, a process called translation.)

In a patient with severely burned skin, the damaged cells that have lost fluid cannot be properly rehydrated because _________.

the disruption of selective permeability allows water molecules that enter these damaged cells to also leave the cytoplasm. (Skin is an organ made up of tissues, and tissues are made up of cells. Selective permeability requires an intact cell membrane.)

What is the most significant factor in the formation of a covalent bond?

the sharing of electron pairs between two atoms, Covalent bonds are formed by the sharing of electrons between two reactive atoms.