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Stack #96115
| Question | Answer |
|---|---|
| What is the simplest atom? | the hydrogen proton |
| What is the ratio of protons to electrons in an atom? | #protons=#electrons |
| What is the atomic number? | the atomic number is the number of protons in the element |
| How is atomic weight determined? | atomic weight includes the weight of protons and neutrons; electrons are virtually weightless |
| Why don't inert gases react? | They have full electron shells |
| What are isotopes? | elements containing the same # of protons but a differing # of neutrons, which affects atomic weight. Can also affect the properties of the element. |
| What are the properties of alpha particles? | pulls two electrons away from something else when interacting. Are big and heavy and can't move far on their own; reacts v. strongly. Alpha emitters "lose weight" because they lose protons |
| What are the properties of beta emitters? | Can be thought of as a moving electron, move v. fast and can penetrate meters in the air; adds to particles creating free radicals (unstable/reactive). Can be thougth to "gain weight" because they gain protons. |
| What are the properties of gamma emitters? | v. penetrating, can go right through you (X-rays) |
| Radioactive emitters can clip and mutate ...? | DNA, can create free radicals which cause cell death. |
| What is a half-life? | the time it takes for the radioactive element to lose half of its radioactivity; in pharmaceuticals indictes when half of the drug action is used up |
| What is avagadro's number? | 6.02 x 10^23 |
| What is a covalent bond? | A bond where elements share electrons to fill the outer electron shells of each other. |
| Which bond is the strongest bond? | Covalent bond |
| Name two weaker bonds | ionic bonds, hydrogen bonds |
| What is an ionic bond? | not a true bond; elements with almost empty or almost full electron shells attract each other and steal/share electrons to fill/empty their outer shell; creates opposite charges on each element (ions) |
| What is a hydrogen bond? | unique to water; water molecules orient themselves so that the O end of the molecule faces the H end of another molecule, due to polarizaiton created by the "rabbit ear" form of H2O. |
| What are van der waals forces? | not bonds, but attraction. not present in polar molecules but rather organic chemistry |
| What is a chemical reaction? | a process whereby bonds are broken or new bonds are formed. |
| What is exothermic reaction? | One that expels heat as a byproducts. Forming bonds creates heat. |
| What is an endothermic reaction? | One that requires energy to be done; breaking bonds requires energy. |
| What is the effect of a catalyst? | Catalysts lower the activation energy required for a reaction to proceed. |
| What are catalysts (composition)? | In humans, they are large protein molecules (enzymes) |
| What is an acid? | a proton donor, watery, bitter |
| What is a base? | a proton acceptor, feels slimy |
| How do you measure the strength of an acid/base (pH) | measure the amount of H+ ions present |
| Each change in pH is a ...? | 10x increase/decrease in the log of H+ concentration |
| What is the difference between strong and weak acids in solution? | Strong acids completely break up into their component ions, whereas weak acids keep an equilibrium by constantly changing back and forth to their acid and non-acid form |
| What are the component ions for the following acids: HCl, and CH3COOH? | HCl = H+ and Cl- ; CH3COOH = H+ and CH3COO- |
| What are the component ions of the following bases: NaHCO3, NaOH? | NaHCO3 = Na+ and HCO3- ; NaOH = Na+ and OH- |
| What is a buffer? | A system of molecules that act to reduce large changes in pH; a weak acid/base which can absorb free H+ |
| Which buffer system is the chief buffer system of extracellular fluid? | the bicarbonate buffer system |
| What does the bicarbonate buffer system do? | works to absorb excess H+ and prevent acidosis |
| Which buffer system is the chief buffer of urine, and also works in cells? | Phosphate buffer system |
| What is the chemical reaction for the bicarbonate buffer system? | H2O + CO2 <--> H2CO3 <--> H+ + HCO3- |
| What is the chemical reaction for the phosphate buffer system? | H2PO4- <--> H+ + HPO4- |
| Which buffer system is the chief intracellular buffer? | Protein buffer system. |
| Which components of protein in the protein buffer system are key? | The carboxyl group (COOH) can donate an H+ while the amide group (NH2) can pick up H+ |
| What causes you to breathe? | The brain detects excess H+ ions (a result of excess CO2 dissolved in tissues and blood) and causes you to breathe to prevent acidosis. |
| Which organs are the main players in maintaining body pH? | The kidney and the lung. |
| How does the lung expel acid? | The lung reduces acid by blowing out CO2. Carbonic acid equation then shifts to the left. |
| How does the kidney regulate pH? | if detects acidity, pumps H+ ions into the urine. |
| How does the kidney pump H+ ions into the urine? | Using intercalated cells in the collecting duct; a form of active transport. |
| How can you measure the pH of the newborn? | cord blood sample. |
| How do newborns differ from adults in terms of pH and buffers? | Babies can have higher acidity; average pH is 7.22. They also have high partial pressure of CO2 and lower amounts of bicarb. |
| Why do pregnant women often hyperventilate? | Effect of progesterone on the brain causes them to feel short of breath, therefore they breathe a bit deeper and/or faster. After long periods of losing CO2 they start to lose bicarb as well making them stay slightly alkaline. |
| Why is a slightly alkaline mom favourable to her baby? | Creates an effective concentration gradient for the baby (who is high in CO2) to dump its acid since it can't expel acid through its lungs. |
| Why can being slightly alkaline be dangerous for the mother? | If she suddenly becomes acidic, she does not have the buffering capacity to deal with it. |
| What is a result of mother becoming acidotic? | Maternal tachycardia to get blood to lungs quicker (to dump CO2), fetal bradycardia to prevent baby from taking in too much acidic blood |
| What results from severe acidosis? | depression, coma, death |
| What results from severe alkalosis? | agitation, spasm, convulsive tetanic death |
| What is the definition of respiratory acidosis? | a PCO2 of >45mmHg and decreased pH if there is no compensation |
| What are common causes of respiratory acidosis? | Hypoventilation |
| What is the compensatory mechanism in respiratory acidosis? | Renal: the kidney increases the excretion of H+, increases the reabsorption of HCO3- |
| How can you tell if the compensation in respiratory acidosis is complete? | pH is normal but the PCO2 will remain high. |
| What is the definition of respiratory alkalosis? | a decreased PCO2 and an increased pH if there is no compensation. |
| What are common causes of respiratory alkalosis? | Hyperventilation |
| What is the compensatory mechanism for respiratory alkalosis? | Renal: the kidney decreases the excretion of H+ and decreases the reabsorption of HCO3-. |
| How can you tell if the compensation for respiratory alkalosis is complete? | The pH will be in the normal range, but PCO2 will be low. |
| What is the definition of metabolic alkalosis? | Increased HCO3- levels and increased pH if there is no compensation |
| What are the common causes of metabolic alkalosis? | Loss of acid; excessive intake of alkaline drugs (i.e. tums) |
| What are some ways that a person could lose acid? | Vomiting, gastric suctioning, use of some diuretics |
| What is the compensatory mechanism in metabolic alkalosis? | Respiratory: hypoventilation (slowed/shallow breathing) which slows CO2 loss. |
| How can you tell if the compensation in metabolic alkalosis is complete? | The pH will be in the normal range, but HCO3- will be high |
| What is the definition of metabolic acidosis? | HCO3- levels are decreased and there is decreased pH if there is no compensation |
| What is the common cause of metabolic acidosis? | Loss of bicarbonate ions |
| How can a person lose bicarbonate ions? | Diarrhea, accumulation of acid (i.e. in ketosis), renal dysfunction |
| What is the compensatory mechanism in metabolic acidosis? | Respiratory: hyperventilation (increased rate/depth of breathing) which increases the loss of CO2 |
| How can you tell if compensation in metabolic acidosis is complete? | The pH will be in the normal range but HCO3- will be low |
| Why is it advantageous for the baby when a pregnant woman to be in compensated respiratory alkalosis? | This means that the mother's blood will have less CO2 in it (it will be less acidic) which means the baby has an easier time excreting the CO2 it produces because the concentration gradient of CO2 is in its favour (Mom's blood CO2 less than baby's) |
| Why can being in a state of respiratory alkalosis be dangerous for the woman in labour? | The woman's buffering capacity is decreased (buffers being used already to compensate for her alkalosis) which means that if she begins to go acidotic (i.e. if blood sugar dips too low and she starts using ketones for energy) she'll quickly become acidoti |
| What are two examples of suspensions? | Blood, raisin bran (i.e. the raisins settle to the bottom, that's why you shake it up!) |
| How is gas pressure in solution expressed? | mmHg (millimeters of mercury) |
| What is normal blood oxygen pressure? | normal blood PO2= 100-104 mmHg |
| How are solids in liquids measured? | weight volume (w/v) or percent by weight [w/v%] |
| What is the percent by weight solution of physiological saline? | O.9% NaCl or 0.9g NaCl per 100ml of saline solutino |
| How are liquids in solution measured? | percent by volume [v/v%] |
| What is the 'international unit' (IU) and how is it expressed? | a determined amount adopted as a standard of measurement, usually expressed by units/litre |
| What is the Gaussian (normal) distribution? | a bell curve where the majority (95%) of the population would fall within 2 standard deviations of the mean/average |
| What part of the normal curve/distribution is referred to as the reference range (RR)? | The values which fall within 2 standard deviations (SD) of the mean |
| What does the reference range normally indicate? | Test results which fall within the reference range are usually considered normal |
| Why can't the same reference range be used for all people? | For many tests, "normal" ranges differ between genders, children and adults, pregnant vs. non-pregnant women, older adults and younger adults due to differences in body physiology |
| What are some reasons that test results might vary even within samples from the same individual? | body chemistry differs at different times of day, during different stages of pregnancy, due to difference in sampling by lab staff, because of dehydration, etc. |
| What is the difference between sensitivity and specificity of tests? | Sensitivity in a test refers to how well the test detects people WITH disease whereas specificity refers to the test's ability to identify those people WITHOUT disease. |
| What is a true negative (TN) result | The test indicates that the person does not have the disease and the test is correct |
| What is a true positive (TP) result? | The test indicates that the person has the disease and the test is correct. |
| What is a false negative (FN) result? | The test indicates that the person does not have the disease when really they do have the disease (test is incorrect) |
| What is a false positive (FP)? | The test indicates that the person has the disease when in fact they do not have the disease (the test is incorrect) |
| What is the formula for determining the specificity of a test? | specificity = TN/(FP +TN) x 100 |
| What is the formula for determining the sensitivity of a test? | sensitivity = TP/(FN +TP) x 100 |
| Why is it that most tests cannot avoid all FPs and FNs? | because values in the reference ranges for healthy and diseased states often overlap, meaning that a healthy person may have a value that falls into the diseased range and a diseased person may have a value that falls within the healthy range. |
| Free thyroxine values less than the RR indicate hypothyroidism. In pregnancy maternal levels of fT4 decrease. How would you avoid false positives? | You would change the diagnostic cut-off to suit the reference range of pregnant women |
| The incidence of PKU in the population of newborns is 1/10000. About 1/1000 PKU tests is positve and all cases of PKU are detected. What is the sensitivity and specificity of the test? | sensitivity = 100% (all cases are caught); specificity = TN/(FP+TN)x100 = 9990/(9+9990)x100 = 99.9% Specificity |
| Screening for phenylketonuria (PKU) has many false positive tests, why? | Because PKU is such a serious disease whose effects can be prevented with proper treatment, the test is set for 100% sensitivity. In this case, the test is still fairly specific. |
| What is positive predictive value? | the likelihood that the test, if reported positive, is actually positive |
| How is positive predictive value calculated? | PPV = TP/TP+FP x 100 |
| What is an alkane? | molecules with only carbon and hydrogen elements with single bonds |
| What is an alkene? | a molecule with only carbon and hydrogen but which has at least one carbon-carbon double bond (C=C) |
| Why are alkanes considered 'saturated'? | Because they have a hydrogen atom bound to each potential binding site |
| Name the alkanes that contain 1-10 carbons, in order | Methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane (hint you really only need to memorize 1-4 because the rest have numbered prefixes :)) |
| How can you identify a hydroxyl group? | The molecule contains an -OH group at the end of a hydrocarbon chain. (R-OH) |
| How can you tell from the name of a molecule that it is an alcohol/contains the hydroxyl functional group? | The word has the suffix -ol (ex. methanol: CH3OH) |
| How can you identify an aldehyde? | The molecule contains an oxygen atom double-bonded to a terminal carbon in a hydrocarbon chain (on the end). |
| How can you tell from the name of a molecule that it is an aldehyde? | The word has the suffix -al (ex. methanal: H-(C=O)-H) |
| How can you identify a ketone? | The molecule contains a carbonyl group (oxygen atom doubled bonded to a carbon atom) in the middle of the chain (ie. not bound to a terminal carbon). This means that a ketone can only be formed in hydrocarbon chains with three or more carbon atoms. |
| How can you tell from the name of the molecule that it is a ketone? | The word has the suffix -one (ex. propanone/acetone: CH3-(C=O)-CH3) |
| What is a structural isomer? | A structural isomer is a molecule that has the same chemical formula as another molecule, but a different structure. |
| What is the difference between cis and trans isomers? | Cis isomers occur when two of the same atom occur on the same side of the molecule; trans isomers have the same atoms on opposite sides of the molecule. |
| How can structural isomers affect molecular function? | Different structural isomers can have different reactivities. |
| How can you identify an amino group? | The molecule contains -NH2 (amide). |
| How can you identify a carboxylic acid group | The terminal carbon is double bound to an oxygen atom and singly bound to an -OH (hydroxyl group) ex. R-(C=O)-OH |
| What is an ester? | An ester is a derivative of carboxylic acid. It involves a carbon atom double bound to an oxygen atom and singly bound to another oxygen atom (which is bound to the "rest" (R) of the molecule: R-(C=O)-OR |
| How can you tell from the name of a molecule if it is an ester? | The word has the suffix -ate (ex. glutamate) |
| What is an ester bond? | An ester bond is the formation of an ester during the formation of a bond between two molecules. They are found in building fats. |
| Using the starting point of an alkane with 3 or more carbons, list the chemical formulas of the various molecules that could be formed by the functional groups we have learned. | Propane: CH3CH2CH3, propene: CH3CH2CH2, propanol: CH3CH2CH2OH, propanal: CH3CH2COH, propanone: CH3CHOCH3, propanoic acid: CH3CH2COOH, propanamide: CH3CH2CONH2, propanate: CH3COOCH3 |
| What is the definintion of a carbohydrate? | a chemical substance that contains only carbon, hydrogen, and oxygen molecules. |
| What are some examples of carbohydrates? | sugar, starch, cellulose, glycogen |
| How much carbohydrate is found in the body? | 1-2% cell mass; 3% body mass |
| What is a monosaccharide? | A sugar molecule with five or six carbons (pentoses, hexoses) |
| How can you tell by the name of a molecule that it is a sugar? | The word has the suffix -ose. |
| What are some examples of monosaccharides? | glucose, fructose, ribose |
| What is a disaccharide? | two monosaccharides joined together to form one molecule. |
| What is an example of a disaccharide? | sucrose, maltose, lactose |
| What is a polysaccharide? | a long polymer of monosaccharides bonded together. |
| What are some examples of polysaccharides? | glycogen, starch, cellulose |
| Starch and cellulose are both polymers of glucose. How can you tell the difference between them? | In cellulose, glucose molecules are linked by a beta-glycosidic link (cis orientation of the hydrogen atoms on the carbons beside the O atom); In starch, glucose molecules are linked via alpha-glycosidic links (trans orientation of the hydrogen atoms) |
| What is dehydration synthesis? | Forming bonds between sugars (or other molecules) by removing a water molecule. |
| What is hydrolysis? | Splitting bonds by adding a water molecule. |
| Why must humans break down di- and poly- saccharides before absorption? | The molecules are too large to cross our cell membranes. |
| What are enzymes? | Enzymes are protein molecules that catalyze reactions in our body. |
| How can you tell from the name of a molecule that it is an enzyme? | The word has the suffix -ase. |
| What are some important enzymes in the body and what are their functions? | amylase- breaks down starch (salivary amylase secreted in the mouth by salivary glands, pancreatic amylase secreted into stomach by pancreas); lactase - breaks down lactose, pepsin - breaks down proteins in the stomach; etc. |
| What types of sugars can be found in the blood? | Only glucose is found in the blood. Galactose and fructose are converted to glucose before entering the bloodstream. |
| Why can't newborns digest starch? | They dont' have enough amylase being produced, however amylase production can be induced by feeding the baby starchy foods. |
| When do babies begin producing amylase? | At about 6 mos. of age. |
| How are glucose, fructose, and galactose transported across the gut epithelium (lining of the stomach)? | Fructose enters by facilitated diffusion, while glucose and galactose require ATP transport to cross the epithelium. |
| Why might premature babies be lactose intolerant? | They only start producing lactase at 36 weeks of age, but production is induceable so the intolerance should usually be just initially. |
| Why are babies considered to have a porous or 'leaky' gut? | Their intestines are able to aborb large molecules to facilitate obtaining passive immunity (mom's antibodies) from breastmilk. |
| Why might babies' porous guts be a problem? | The pores in the gut are not specific; they can absorb multiple molecules that they ingest (cow's milk, eggs). Could lead to intolerance to these molecules because their immune system might identify them as foreign and make antibodies against them. |
| What are proteins? | Molecules formed from long chains of amino acids joined by peptide bonds. |
| What is an amino acid? | An amino acid is a molecule with an amino group (NH2) on one end of the molecule and a carboxyl group (COOH) on the other. |
| What is a dipeptide? | A molecule consisting of two amino acids bonded together |
| What is a polypeptide? | A protein with up to 25 amino acids. |
| Give an example of a polypeptide. | Oxytocin |
| What is the primary structure of a protein? | A "line" of amino acids |
| What is the secondary structure of a protein? | The "lines" of amino acids join in such a way that they form a circular helix OR a pleated sheet. |
| What is the tertiary structure of a protein? | A 3-D combination of circular helices and pleated sheets folding back on themselves. |
| What is the quaternary structure of a protein? | The combination of one or more tertiary proteins into a single molecule (ex. hemoglobin) |
| Do all proteins have primary, secondary, tertiary and quaternary structure? | NO. Each structure forms as the protein gets bigger/proteins become more complex as they increase in size. |
| How many different amino acids are available to form proteins in the human body? | 22 |
| What is an essential amino acid? | An amino acid that cannot be formed within our bodies, which we must consume in food. |
| How many amino acids are essential in humans? | 10 |
| List the essential amino acids | arginine, histidine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine, leucine |
| What types of food contain all 10 essential amino acids? | animal and soy protein |
| What is allergic gastroenteropathy? | allergic disease of the stomach and intestines. |
Created by:
mccals2
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