Water. pH, Buffers and Acid-Base Balance

Question 1

The ff are properties of ____:

Ability to Solvate Organic and Inorganic Molecules

Nucleophile

Ability to Ionize→Tendency to Dissociate

Answer 1

Water

Question 2

T/F: Water acts both as an acid and base, thus impacts pH

Answer 2

True

Question 3

Water molecules from dipoles due to

Answer 3

strong electronegativity of oxygen, the O atom attracts electrons away from the H nuclei creating a partial charge between O (-) and H (+). T

Question 4

feature that allows water to weaken the forces between charged and polar molecules.

Answer 4

dielectric constanst

Question 5

Water has a low dielectrict constant (T/F)

Answer 5

False; high

Question 6

Water decreases the force of attraction between charged and polar species relative to water- free environments with (lower/higher) dielectric constants

Answer 6

Lower

Question 7

Water has a high viscosity, surface tension, and

boiling point due to

Answer 7

hydrogen bonds

Question 8

The oxygen atoms of aldehydes, ketones, and amides provide

lone pairs of electrons that can serve as hydrogen____.

Answer 8

acceptors

Question 9

Alcohols, carboxylic acids, and amines can serve as as hydrogen donors of unshielded hydrogen atoms for formation of hydrogen bonds

Answer 9

False: donors and acceptors

Question 10

° Carbonyl carbons in amides, esters, aldehydes, and ketones.
° The phosphorus atoms of phospho-esters.

Electrophiles or nucleophiles?

Answer 10

Electrohpiles

Question 11

° The oxygen atoms of phosphates, alcohols, and carboxylic acids ° The sulfur of thiols
° The nitrogen atom of amines

Electrophiles or nucleophiles?

Answer 11

Nucleophiles

Question 12

Thermodynamics that govern the equilibrium point of a reaction
determines the rate at which it will proceed toward its equilibrium point (t/f)

Answer 12

False; does not

Question 13

Covalent and non-covalent bonds stabilize biologic molecules (t/f)

Answer 13

truw

Question 14

A ____ bond is the stronger bond that holds biologic molecules
together. ____ have a lesser magnitude of force

Answer 14

Covalent; non-covalent

Question 15

Tendency of nonpolar compounds to self-associate in aqueous

environments

Answer 15

hydrophobic interactions

Minimizes disruption of energetically favorable interactions
between surrounding water molecules
− Hydrogens of non-polar groups do not form H-bonds
− Water molecules adjacent to hydrophobic group are restricted in
forming H-bonds

Question 16

Salt bridges: electrostatic interactions between oppositely charged groups

Answer 16

Electrostatic interactions

Act over a larger distance than H-bonds
° Facilitate binding of charged molecules and ions to proteins and
nucleic acids

Question 17

Come from attraction between transient dipoles
° Transient dipoles due to the distance between atoms or
molecules

Answer 17

Van der Waals forces

Weaker but more numerous than H-bonds
° Acts in a shorter distance

Question 18

Determine the bonds in DNA:

___ hold together each DNA strand
___ between nucleotide base pairing
___ between stacked purine and pyrimidine bases

Answer 18

covalent, h bond, van der waals

Question 19

Buffer systems in the body

Answer 19

chemical buffering system protein buffering system, respiratory and renal

Question 20

Chemical buffering systems

Answer 20

bicarbonate, phosphate, proteins

Question 21

The Hydrogen ion concentration in the body and its balance in the body fluid systems

Answer 21

Acid-base balance

Question 22

Acid-base balance is controled by

Answer 22

buffers

Question 23

ph level that is normal arterial ph ofour body

Answer 23

7.4

Question 24

What do buffers do

Answer 24

Instead of eliminating excessive Hydrogen ions, they are trapped until balance is reestablished.

Question 25

Most important buffer system in the ECF because it can regulate acid base balance within seconds

Answer 25

Bicarbonate buffer system

Question 26

regulates bicarbonate buffer syste,

Answer 26

carbonic anhydrase

Question 27

``` Consists of: − Acid: H2CO3 (Carbonic Acid) ° Easily dissociates to CO2 and water OR to H+ and HCO3- Base: HCO3- (Bicarbonate ion) Salt: NaHCO3 (Sodium Bicarbonate) Enzyme: Carbonic Anhydrase ```

Answer 27

Bicarbonate buffer system

Question 28

Bicarbonate Buffer: in order restore balance in the presence of strong acid, 1) hydrogen concentration increases or decreases? 2) system shifts to left or right? 3) producing more or less CO2?

Answer 28

1) increases 2) left 3) more

Question 29

Bicarbonate Buffer: in order restore balance in the presence of strong base, strong base reacts with H2CO3 1) producing more or less HCO3-? 2) system shifts to left or right?

Answer 29

1) more | 2) right

Question 30

Why is bicarbonate buffer strongest in lung alveoli and kidney tubules

Answer 30

carbonic anhydrase is present in the ECF of these areas

Question 31

Equation to quantify amounts

Answer 31

Henderson-HAssebach Equation = pH = pKa + log (concentration of conjugate base/concentation of weak acid)

Question 32

ph level of acidosis

Answer 32

6.8 < pH < 7.4

Question 33

ph level of akalosis

Answer 33

7.4

Question 34

high HCO3-, low PCO2

Answer 34

alkolatic

Question 35

low HCO3-, high PCO2

Answer 35

acidotic

Question 36

A buffer can be considered as efficient if

Answer 36

the concentration of the acid and the base are equal

Question 37

Main buffer system in ICF

Answer 37

Phosphate Buffer Systwm Acid: H2PO4- (Dihydrogen Phosphate) Base: HPO4-2 (Hydrogen Phosphate) Salt: Na2HPO4 (Disodium Phosphate)

Question 38

why is phosphate buffer system active in ICF

Answer 38

− Abundant in the tubular fluids in kidneys (ICF) | − Higher concentration of phosphate in proximal tubules

Question 39

phosphate system has a better efficiency in titration curve compared to bicarbonate

Answer 39

True; However, this is not used as often because this system is only abundant in the tubular fluid of the kidneys

Question 40

Protein pK is near intracellular pH ● Slow buffer, might take several hours before steady state is achieved ● Abundant in ICF and ECF

Answer 40

Protein Buffer SYstem

Question 41

Protein buffer has effective ICF buffers because molecules are ___

Answer 41

molecules are ampotheric

Question 42

ECF buffer of protein bfufer

Answer 42

hemoglobin (Facilitates exchange of O2 and CO2 from lungs to tissue and vice versa) Buffer for CO2 and H+ ° 10% of CO2 is dissolved in the plasma ° 20% of CO2 is combined with Hemoglobin, forming Carbaminohemoglobin 􏰀 The Carbaminohemoglobin produced is then released to the lungs ° 70% reacts with H2O to form HCO3-

Question 43

protein buffeR: The HCO3- produced goes out to the ECF in exchange for

Answer 43

chloride ions

Question 44

acts within a few minutes to eliminate CO2 from the body

Answer 44

respiratory control

Question 45

Respiratory control uses ____ system becuase this is usually done in the lungs

Answer 45

bicarbonate buffer system

Question 46

High metabolic activity→__ low or high CO2→low or hhigh ___ H+ ion in the body

Answer 46

high, highh

Question 47

Increase in CO2 will push the equation to the (left or right), (decreasing/increasing) H+ ions, thereby inducing a more (acidic/basic) environment

Answer 47

right; increasing; acidic

Question 48

A decrease in ventilation will decrease/increase the CO2 inside the body because more/less CO2 is blown off, which decreases/increases H+ concentration in the body

Answer 48

increase; less; increases

Question 49

this mechanism is applied to regulate changes in PCO2 and H+

Answer 49

Negative feedback control

Question 50

Feedback control mechanism: increase in concentration of H+ = (1) in Alveolar ventilation = (2) PCO2 in blood→ Alveolar ventilation rate will not (3) anymore because concentration of H+ is not that (4) anymore

Answer 50

increasel decrease; decrease; high

Question 51

Hyperventilation/ respiratory alkalosis: (1) in ventilation means an (2) in CO2 blown away, which (3) CO2 in the body, thereby (4) H+ (acidity) in the body

Answer 51

increase; increase; decrease; decrease

Question 52

Fever − Anxiety − Severe asthma − High altitude position are causes of

Answer 52

hyperventilation / respiratory alkalosis:

Question 53

respiratory acidosis: (1) in ventilation means a (2) in CO2 blown away, which (3) CO2 in the body, thereby (4) H+ (acidity) in the body

Answer 53

decrease, decrease, increase, increase

Question 54

Chronic Obstructive Pulmonary Disease − Chest wall tumors − Narcotic use causes of

Answer 54

Causes of respiratory acidosis

Question 55

The slowest buffer system (hours to days)

Answer 55

renal

Question 56

how does renal eliminate excess of acid or base

Answer 56

altering ph of urine

Question 57

end arteries; filters blood

Answer 57

glomerulus

Question 58

where urine is concentrated before it leaves | the body

Answer 58

tubular systems

Question 59

Renal control uses the ____ system

Answer 59

Bicarbonate Carbonate anhydrase can be found in the tubular cells

Question 60

Cells of the tubules (tubular cells) surrounded by interstitial fluid

Answer 60

Bicarbonate system Tubular lumen - area where urine is concentrated in

Question 61

Processes of Bicarbonate System (3)

Answer 61

Filtration of HCO3-, Active Secretion H+ and Active. Reabsorption of HCO3- Filtration of HCO3-: Bicarbonate ions are continuously filtered in the urine. − Active secretion H+: Hydrogen ions are continuously secreted into the urine. ° They can also leave via the phosphate buffer system and via the ammonia buffer system. ° Active secretion occurs since H+ ions would have to go against the concentration gradient (low concentration→high concentration). ° This process allows the acid to be removed from the blood. − Active reabsorption of HCO3-: Bicarbonate is actively reabsorbed through the bicarbonate buffer system ° In the proximal tubule cells of the kidney.

Question 62

Involves active secretion and reabsorption

Answer 62

steady state (bicarbonate system) General process: ° Carbon dioxide can pass through any cell. ° CO2 can enter tubular cells from the interstitial fluid or from the tubular lumen. ° Inside the cells: CO2 + H2O → H2CO3 → HCO3- + H+ 􏰀 Carbonic acid is produced by the enzyme carbonic anhydrase. 􏰀 Carbonic acid rapidly dissociates into bicarbonate and hydrogen ions, then bicarbonate is actively reabsorbed back in the system. 􏰀 For every active reabsorption of bicarbonate, there is a hydrogen ion that is secreted. However, there is still a lot of hydrogen ions that we need to secrete or buffer so there is no acid-base imbalance.

Question 63

Excretion of excess H+ can be buffered through 2 more systems

Answer 63

Renal control (Bicarbonate system)

Question 64

System in renal control: High phosphate in tubular lumen → whenever hydrogen ions are excreted, filtered hydrogen phosphate buffers the process so that hydrogen can be excreted.

Answer 64

phosphate buffer system

Question 65

Ammonium is secreted from the tubular cells which then buffers with the hydrogen ion to become ammonia (NH4) which is then excreted through the urine

Answer 65

ammonia buffer system

Question 66

metabolic abnormalities depend on the amount of ____ in the body

Answer 66

bicarbonate

Question 67

Metabolic Alkalosis (decreased/increased) amount of bicarbonate: ° Hydrogen ion concentration (decreased/increased) to reach equilibrium ° As a result, pH (decreased/increased)

Answer 67

increased; decreased; increased

Question 68

Metabolic Acidosis (decreased/increased) amount of bicarbonate: ° Hydrogen ion concentration (decreased/increased) ° As a result, pH (decreased/increased)

Answer 68

decreased, increase, decrease

Question 69

Metabolic abnormality that leads to ° Vomiting gastric contents that are acidic ° Ingestion of alkaline drugs (ex. peptic ulcer)

Answer 69

metabolic alkalosis

Question 70

Metabolic abnormality that leads to − Situations that lead to metabolic acidosis ° Diarrhea ° Vomiting intestinal contents that are alkaline ° Starvation ° Diabetic ketoacidosis

Answer 70

metaboic acidosis

Question 71

Electric force (F) between oppositely charged particles is inversely proportionate to the dielectric constant ε.

Answer 71

coulombs law

Question 72

ucleophilic attack by water typically results in the cleavage of the amide, glycoside, or ester bonds that hold

Answer 72

hydrolysis

Question 73

catalyze the hydrolysis of proteins into their component amino acids.

Answer 73

proteases

Question 74

catalyze the hydrolysis of the phosphoester bonds in DNA and RNA.

Answer 74

nucleases