Physiology Unit 1 Review
What is the result of an impediment or complete failure of the body to compensate for an outside influence that disrupts its homeostasis?
Disease
Compartmentation allows cells to regulate metabolic reactions by A. making some reactions reversible B. maintaining an optimum ADP:ATP ratio C. decreasing the activation energy of some reactions D. increasing some equilibrium constants E. isolating some enzymes within organelles
E
What do the nucleotide molecules, NADH, FADH2, and NADPH have in common? A. They are carriers of high-energy electrons B. They are important enzymes in metabolism C. They are involved in energy coupling D. They take energy from ATP E. More than one of the above
E
What term is used to describe closely related proteins whose function is similar but whose affinity for ligands may differ? A. isotopes B. agonist C. antagonist D. modulator E. isoforms
E
Which of the following affects the speed at which reactants disappear and products appear during a chemical reaction? A. substrate concentration B. temperature C. presence of cofactors D. pH E. all of the above
E
Which of the following has lost an electron? A. N2 B. O2- C. 2H D. Cl- E. Na+
E
Which of the following organs or body structures do(es) NOT come in contact with the external environment? A. Bladder B. Ducts of salivary and sweat glands C. Stomach D. Uterus E. adrenal Gland
E
Cofactors A. are ions or small functional groups. B. are required for an active binding site. C. compete with ligand for the binding site. D. covalently bind at the active site. E. More than one of the above.
E (AB)
Which of the organ systems exchange materials between the internal and external environments? A. Reproductive B. Integumentary C. Respiratory D. Nervous E. More than one of the above
E. (ABC)
What is energy? In biological organisms, what are the three categories of work? Describe each.
Energy is the capacity to do work. 1) Chemical work = making/breaking of chemical bonds 2) Transport work = enables cells to move ions, molecules, and larger particles through membranes. It is useful for creating concentration gradients. 3) Mechanical work = movement. Organelles moving around the cell, muscle contraction.
What is the role of oxygen in cellular respiration?
Oxygen is the final acceptor of electrons in the ETS.
Describe the levels of structure of proteins.
PRIMARY - chain of amino acids SECONDARY - primaries hyrdogen bonded to form a-helix or B-sheets TERTIARY - 3-D shape of globular or fibrous proteins made with disulfide bonds (S-S) (first structure level that can be a functioning protein) QUATERNARY - multiple subunits noncovalently bonded.
Define reflex control.
Any long-distance pathway that uses the nervous and/or endocrine system to maintain homeostasis.
What is an ion?
Atoms that have lost (cation) or gained a/an electron(s), and are thus charged.
A diver stands poised on top of the platform for a second and then dives into the water below. Which of the following is(are) true? A. Kinetic energy is transformed to potential energy. B. Potential energy is transformed to kinetic energy. C. The energy associated with the dive is the same energy stored in chemical bonds and concentration gradients. D. More than one of the above.
B
What is physiology?
The study of the normal functioning of living organisms and its component parts.
Enzymes increase reaction rates by A. raising reaction temperature B. decreasing activation energy C. decreasing reaction temperature D. increasing activation energy E. altering the binding site
B
Most cells are in direct contact with A. the external environment B. extracellular fluid C. blood D. air E. All of the above
B
The alpha-helix and pleated sheet are examples of the _______ structure of a protein. A. primary B. secondary C. tertiary D. quaternary E. pentanary
B
The role of oxygen in cells is to A. catalyze reactions in glycolysis B. act as an electron acceptor C. produce ATP D. produce CO2
B
Tom is waiting at the start line for the race to begin. His heart rate is starting to increase and he is breathing a little faster. This is an example of A. positive feedback B. feedforward control C. negative feedback D. reflex control E. local control
B
Using this equation predict what would happen if pH of the blood decreased. CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3 A. The decrease in H+ concentration would lead to the removal of excess CO2 by the lungs. B. The increase in H+ concentration would lead to the removal of excess CO2 by the lungs. C. The decrease in H+ concentration would result in excess HCO3. D. There would be no change.
B
Which of the following is NOT a product of glycolysis? A. ATP B. CO2 C. Pyruvic acid D. NADH + H+
B
Which of the following is a key intermediate of glucose catabolism to the citric acid cycle? A. ATP B. Pyruvate C. Oxygen D. Lactate E. Glucokinase
B
What is the drawback of having only a single control system (a heater) for maintaining aquarium water temperature in some desired range?
There is no control mechanism for cooling water that is too warm.
Which organ system forms a protective boundary separating the body's internal environment from the outside world? A. Urinary B. Respiratory C. Integumentary D. Reproductive E. Musculoskeletal
C
Why are proteins so important in the human body?
They run a cell from day to day. They act as enzymes, membrane transporters, signaling molecules (hormones), receptors, binding proteins, immunoglobulins, and regulatory proteins.
What are enzymes? What is their role/how do they work? How enzymes used as diagnostic tools?
Enzymes speed up the rate of a chemical reaction by lowering the activation energy. Damaged cells release enzymes into the blood, which can be detected and lead to a diagnosis.
How does homeostasis differ from equilibrium?
Equilibrium implies that the composition of body compartments is identical, but for the homeostasis, the compositions can be in disequilibrium. E.g. Na+ & Cl- are far more concentrated in ECF, while K+ is most concentrated in ICF.
Describe glycogenolysis, gluconeogenesis/glyconeogenesis and lipolysis.
GLUCONEOGENESIS - Pathways through which noncarbohydrate precursors, especially amino acids, are converted into glucose. Enzymes break proteins into amino acids. AAs are converted to an organic acid (intermediate) and ammonia by deamination. The ammonia goes to the liver and the organic acid enters into the glycolysis or CAC pathway. LIPOLYSIS - pathway where lipids are broken down into glycerol and fatty acids. Fatty acids are disassembled (could later enter the CAC) and glycerol enters about halfway into glycolysis pathway.
What is the basic process of Protein synthesis starting with DNA (use the following terms: transcription, translation, mRNA, ribosomes, tRNA and amino acid)? List the sequence of protein synthesis.
Gene activation starts the process, and a RNA polymerase attaches to the appropriate site on DNA. The RNA polymerase unzips the DNA and a strand of mRNA is transcribed from the DNA. The mRNA then goes through processing, where it receives a cap and tail and some splicing can occur. Then it exits the nucleus and finds a ribsome. There, tRNA carrying amino acids match their anti-codon to the mRNA codons. The amino acids bond together and create the primary structure of a protein. Then they go through post-translational modifications until they are finished in their tertiary or quaternary structure.
What are isozymes? How are they useful in medical diagnoses?
Isozymes are related forms of a single enzyme; they catalyze the same reaction but under different conditions or in different tissues. If too much of one enzyme is found in the blood, they can see what form it is and what tissues in the body generally produce/use that isozyme to discover where a problem is occurring.
What is the primary role of glycolysis?
It breaks down glucose to form *NADH* and 2 ATP and pyruvate. It happens in the cytosol.
What is the primary role of the citric acid cycle?
It oxidizes acetyl-CoA and produces 1 ATP and *many NADH & FADH2* (electron carriers). It happens in the mitchondrial matrix.
List the four major groups of biomolecules and briefly describe their structures and functions.
LIPID - nonpolar, hydrophoic; composed of C & H; used for *energy* and building blocks of cellular components; macro: fatty acids CARBOHYDRATES - composed of C, H & O; used for *fuel* and limited structure; macro: monosaccharides PROTEINS - composed of C, H, O, & N; macro: amino acids NUCLEOTIDES - composed of base (AGCTU), sugar, phosphate(s); macro: nucleic acids; transmit and store info; composed of C, H, O, N, & P
What control mechanisms help to maintain homeostasis?
Local and reflex control systems monitor and maintain that regulated variables are kept within their acceptable (normal) range.
What is metabolism, catabolism and anabolism?
METABOLISM refers to the collection of all the chemical reactions that take place in an organism. CATABOLISM refers to reactions that release energy and result in the breakdown of large biomolecules. ANABOLISM refers to pathways that require a net input of energy and that synthesize small molecules into larger ones.
Define homeostasis
Maintenance of a relatively stable internal environment
Define the law of mass balance. Express as an equation. How is mass balance maintained?
Mass balance = existing body load + intake or metabolic production - excretion or metabolic removal What goes in, must come out. Maintained by excretion or metabolic removal.
What does the pH scale measure? What is the difference between an acid and a base?
pH measures the concentration of free H+. pH<7=acidic, pH>7=basic. Acids have more free H+ ions.
What are agonists?
Molecules that combine with a receptor and mimic a response.
Does the aquarium heating system operate using positive or negative feedback loop?
Negative
Compare and contrast negative feedback, positive feedback, and feedforward control. Give examples of each.
Negative feedback - A homeostatic feedback loop designed to keep the system at or near a setpoint. They STABILIZE variable. Negative feedback loops can restore the normal state but cannot prevent the initial disturbance. Aquarium example - heater warms the water (response) and removes the stimulus (low water temp). Positive feedback - A feedback loop in which the response REINFORCES the stimulus, triggering a vicious cycle of ever-increasing response. E.g. - hormonal control of uterine contractions during childbirth. Feedforward control - Anticipatory responses that start a response loop in anticipation of a change that is about to occur. E.g - salivating when hungry and someone talks about food.
Explain what happens when homeostasis cannot be maintained.
Normal function is disrupted and a disease state, or pathological condition, may result.
Define the term isoform and describe how isoforms can have an effect on protein binding.
Closely related proteins whose function is similar but whose affinity for ligands differs are called isoforms of one another.
Define saturation.
Condition when active sites on a given amount of protein are filled with substrate and reaction rate is maximal.
A protein placed in a solution becomes unraveled, loses its native conformation, and is rendered biologically inactive. Which of the following is/are true? A. Protein has been denatured. B. Only van der Waals forces have been affected. C. Excess hydrogen ions in the solution disrupted hydrogen bonding. D. Both A and C. E. All of the above.
D
In the reversible reaction A + B <=> C + D, adding an abundance of A will A. convert the reaction to an irreversible forward reaction. B. convert the reaction to an irreversible backward reaction. C. not affect the rate of production of C and D unless more B is added as well. D. tend to drive the forward reaction to make more C and D. E. tend to slow the forward reaction, making less C and D.
D
Physiology is the study of A. the structure of the body B. the tissues and organs of the body at the microscopic level C. growth and reproduction D. the normal functions of the organ systems E. the facial features as an indication of personality
D
Synthesis of RNA from the double-stranded DNA template requires the enzyme A. ligase. B. DNA polymerase. C. transfer RNA (tRNA). D. RNA polymerase. E. ribosomal RNA (rRNA).
D
The aerobic metabolism of one glucose molecule yields ________ ATP. A. 2 B. 6 C. 26-28 D. 30-32 E. more than 38
D
Translation of mRNA produces a string of A. fatty acids. B. glucose molecules. C. nucleotides. D. amino acids. E. nucleic acids.
D
Which of the following is a buffer zone between the outside world and most of the cells of the body? A. blood B. lumen C. lymph D. extracellular fluid E. All of the above
D
Which of the following sequences is correct? A. genes → transcription → RNA → translation → protein B. genes → translation → mRNA → transcription → protein C. RNA → transcription → mRNA → translation → protein D. genes → transcription → mRNA → translation → protein
D
What does protein specificity mean?
The ability of an enzyme or receptor to bind to a particular molecule or a group of closely related molecules.
List and briefly describe the general functions of the cell membrane.
1) Physical isolation, separates ICF from ECF. 2) Regulation of exchange with the environment. 3) Communication between the cell and its environment. Any alteration in the cell membrane may affect the cell's activities. 4) Structural support.
List and describe the four important roles electrons play in physiology. Describe solubility. Why is this important?
1) They form covalent bonds, which are hard to break. 2) They create ions when gained or lost. Ions are the basis for electric signaling in the body. 3) They capture and store energy (high-energy electrons), which allows them to be used for synthesis, movement, etc. 4) They create free radicals (unstable molecules with unpaired electron(s)), which can cause aging, diseases, cancers, etc.
"Down-regulation" refers to increased A. programmed removal of proteins. B. programmed production of proteins. C. transport of nutrients into cell. D. cell division. E. synthesis of membrane.
A
A protein binding to only one kind of molecule or group of closely related molecules is called A. specificity. B. competition. C.affinity. D. saturation. E. facilitation.
A
Lipids are hydrophobic, and do not usually dissolve in water. Because blood is water-based, the lipid cholesterol is combined with ________ so that it can be transported by blood. A. a hyrdophilic molecule B. a hydrophobic molecule C. nothing; cholesterol is not transported in blood D. a cation E. an anion
A
What type of molecule carries each amino acid to a ribosome during protein synthesis? A. tRNA B. mRNA C. DNA D. codon
A
When you stir sugar into your tea, sugar is the A. solute. B. solution. C. solvent. D. emulsion.
A
Which of the following does NOT take place during post-translational modification A. alternative splicing B. folding C. formation of disulfide bonds D. cleavage into fragments E. glycosylation
A
Which of the following is NOT an example of negative feedback? A. Uterine contractions during childbirth B. regulating body temp C. regulating blood sugar D. regulating blood pH E. regulating testosterone levels
A
Which of the following is the correct order for the bonds decreasing in strength? A. covalent → ionic → hydrogen → van der Waals B. van der Waals → hydrogen → ionic → covalent C.covalent → ionic → van der Waals → hydrogen D. ionic → covalent → hydrogen → van der Waals
A
Which of the following molecules is NOT a carbohydrate? A. cholesterol B. deoxyribose C. glycogen D. sucrose
A
Which two systems are the primary control systems of the body? A. Nervous & Endocrine B. Nervous & Circulatory C. Digestive & Nervous D. Endocrine & Circulatory E. Endocrine & Immune
A
What is a ligand?
The molecule that binds to a protein.
What happens if proteins are denatured? What causes denaturation?
When a protein loses its conformation, such as through a change in pH or temperature, it loses its activity, and is then denatured.
A polypeptide chain is placed in an aqueous solution and spontaneously undergoes a conformational change to a 3D shape. Which of the following bond(s) is/are most likely NOT playing a role? A. hydrogen bonds B. Van der Waals forces C. covalent bonds D. ionic bonds
C
A solution with pH 8 has an H+concentration that is _______ a solution with pH 9. A. twice as concentrated as B. one-eighth as concentrated as C. 10 times more concentrated than D. 100 times less concentrated than E. 100 times more concentrated than
C
Glycoproteins consist of A. proteins and lipids. B. lipids and carbohydrates. C. proteins and carbohydrates. D. lipids and nucleotides.
C
If a substance has a pH that is greater than 7, it is considered A.neutral B. acidic C. alkaline D. a buffer E. a salt
C
Table salt (NaCl) is _______. What happens when it is placed in water? A. hydrophilic; Covalent bonds between Na and Cl are broken and they each become surrounded by water molecules. B. hydrophilic; NaCl molecules become surrounded by water molecules. C. hydrophilic; Ionic bonds between Na+ and Cl- are broken and they each become surrounded by water molecules. D. hydrophobic; Nothing happens.
C
The building blocks of proteins are _______ and they are linked together with _______ bonds. A. amino acids, hydrogen B. nucleotides, peptide C. amino acids, peptide D. nucleotides, ionic
C
The linking together of many glucose molecules to form the polymer glycogen is a(n) A. exergonic reaction B. synthesis reaction C. endergonic reaction D. oxidation reaction
C
What type of work involves the making and breaking of chemical bonds? A. transport work B. mechanical work C. chemical work D. physical work
C
Which factor does NOT affect a protein's activity? A. concentration B. pH C. size D. temperature
C
Which of the following is NOT an example of a homeostatic response? A. Body temperature increases, and sweating brings the body temperature down. B. The oxygen level in the blood falls, and breathing harder increases the oxygen level in the blood. C. Sweating leads to loss of body fluids, and urination increases the loss of body fluids. D. Glucose level in the blood falls, and eating increases the glucose level in the blood.
C
Compare and contrast aerobic and anaerobic pathways.
Aerobic utilizes oxygen, whereas anaerobic does not. The metabolic pathways that yield the most ATP molecules are aerobic. The lower ATP yield of anaerobic pathways means that most animals are unable to survive for extended periods on anaerobic metabolism alone.
What is ATP?
An energy-storing compound composed of adenine, ribose, and three phosphate groups. It's the main form of cellular energy.
Briefly describe the actions of the following modulators: chemical modulators, antagonists, competitive inhibitors, irreversible antagonists, allosteric modulators, covalent modulators
CHEMICAL MODULATORS - pH and temperatre can disrupt hydrogren or disulfide bonds which could denature proteins. ANTAGONISTS - aka inhibitors, bind to a protein and decrease its activity. COMPETITIVE INHIBITORS - competes directly with ligand by binding reversibly to active site. IRREVERSIBLE ANTAGONISTS - binds to binding site and can't be displaced. ALLOSTERIC MODULATORS - binds away from binding site and can inhibit or activate the binding site. COVALENT MODULATORS - covalently bind to a protein and changes its activity.
Describe covalent bonds, ionic bonds, hydrogen bonds
COVALENT bonds share pairs of electrons. They are strong single/double/triple bonds that require energy to make/break. They can create polar or nonpolar molecules. IONIC bonds form because of electrostatic attraction between ions. These can be weak bonds that facilitate reversible interactions. HYDROGEN bonds occur when a H atom is attracted to nearby O, N, or F atom. These are weak, easily broken bonds that facilitate reversible interactions.
Define local control and give an example.
Homeostatic control that takes place strictly at the tissue or cell by using paracrine or autocrine signals. E.g. Oxygen concentration in a tissue decreases, so the cells lining the small blood vessels that bring blood to that area sense this and thus secrete a chemical signal that tells the vessel walls to relax. This dilates the vessel, increasing blood flow into the tissue, and brings more oxygen to the area.
Contrast hydrophilic interactions and hydrophobic interactions.
Hydrophobic molecules do not dissolve in water, they are non-polar. Hydrophilic molecules do dissolve in water, they are polar.
What are the differences between intracellular, interstitial, and extracellular fluid?
INTRACELLULAR FLUID is fluid found within the cells. EXTRACELLULAR FLUID is all fluid outside cells. The INTERSTITIAL fluid is the non-plasma portion of ECF; which surrounds most cells of the body.
What is the primary role of the electron transport system?
Shuttles electrons (NAD/FAD) down a series of reactions that release energy used to make 26-28 ATP. Occurs in the mitochondrial cristae.
Describe protein activation. What role do cofactors play in activation?
Some proteins are inactive when they are synthesized in the cell. Before such a protein can become active, enzymes must chop off one or more portions of the molecule (proteolytic activation). Sometimes a cofactor (an ion or small organic functional group) must attach to the binding site to make the protein active. Other times, a modulator binds to a protein away from the binding site to make it active (allosteric activator).
Explain the difference between equilibrium and steady state.
Steady state - materials are constantly moving between 2 compartments. Equilibrium - composition of compartments are identical.
List the parts of the reflex control.
Stimulus -> sensor -> input signal -> integrating center -> output signal -> target -> response
Define and distinguish between the processes of up-regulation and down-regulation.
UP-REGULATION is the increase in protein number or binding affinity that increases the response of the target cell. it UPS the production of new proteins. DOWN-REGULATION is the decrease in protein number or binding affinity that lessens response. It is the programmed removal of proteins.