Biochemistry Lab - Prelims

Carbonate buffer system

When acid is introduced to the blood, the bicarbonate ion reacts with the hydronium ion to produce carbonic acid and water which in turn dissociates into water and carbon dioxide. The latter is excreted from the lungs through exhalation. When a base is introduced to the blood, the carbonic acid reacts with the hydrogen ion to produce bicarbonate ion and water.

Phosphate buffer system

It maintains the pH of the cytosol of the cell. The buffers are dihydrogen phosphate ion, a weak acid, and its conjugate base is hydrogen phosphate ion. When the cytosol becomes acidic, or the pH decreases from 7 to 4, the hydrogen phosphate ions react with the hydronium ions to produce dihydrogen phosphate and water during the reaction. Similarly, when the pH of the cystosol increases from 4 to 7, the dihydrogen phosphates ions react with the OH- ions to produce hydrogen phosphate ions and water during the reaction.

Proteins

The carboxyl group is deprotonated because the hydroxide ions react with the carboxyl group, producing its conjugate base and water during the reaction, and the decreasing the pH.

7.00

If the pH of 100 mL of distilled water is 7.35 and one drop of 0.05 M HCl is added, the pH will change to __

25 mL of 0.05 M HCl

To change 100 mL of ‘normal’ blood from pH of 7.35 to 7.00, approximately __ is needed.

1300 mL of HCl

With 5.5 L of blood in the average body, more than __ would be required to make the same change in pH.

regulating blood pH

The lungs and kidneys play important role in ___

retention or elimination of CO₂

The lungs regulate pH through __ by changing the rate and volume of ventilation

kidneys

The __ regulate pH by excreting acid, primarily in the ammonium ion (NH_4⁺), and by reclaiming HCO₃^- from the glomerular filtrate

excreting acid

The kidneys regulate pH by __, primarily in the ammonium ion (NH_4⁺), and by reclaiming HCO₃^- from the glomerular filtrate

proton acceptors

proteins contain -COO- groups, which, like acetate ions (CH₃COO-), can act as __

donate protons

proteins contain -NH₃⁺ groups, which, like ammonium ions (NH_4⁺), can __

Diffusion

is the net movement of molecules or ions from region of higher concentration to a region of low concentration

Osmosis

is a simple diffusion of solvent across a membrane that is more permeable to the solvent that it is to the colute

osmotic pressure

is the force needed to prevent osmosis. (higher concentration → higher __ )

surface tension

is a property due to the tendency of the fluid surface to contract and behave as if it is enclosed in an elastic membrane

soaps and detergents

__ lower the surface tension

Faster diffusion

__ of the crystals which resulted in the production of dark colored solution

Slower diffusion

__ of the crystals which resulted in the production of light colored solution

shorter time

Distilled water + hexane: Requires __ for the bubbles to coalesce. Presence of strong force of attraction or surface tension

strong force of attraction

Distilled water + hexane: Requires shorter time for the bubbles to coalesce. Presence of __ or surface tension

weak intermolecular force

Distilled water + hexane + detergent solution: Requires longer time for the bubbles to coalesce. Presence of __ or surface tension

longer time

Distilled water + hexane + detergent solution: Requires __ for the bubbles to coalesce. Presence of weak intermolecular force or surface tension

temperature increase

As the __, the kinetic energy of the solute particles also increases, causing them to move more rapidly and collide with each other more frequently.

Dialysis

the process by which waste products and excess solutes are removed from the blood by passing it through a semipermeable membrane

cell membrane

It plays a crucial role in the dialysis process by allowing the passage of certain solutes while blocking the passage of others, which helps remove waste products from blood

Renal insufficiency

also known as chronic kidney disease (CKD), is a progressive condition characterized by gradual loss of kidney function overtime.

Hemodialysis

In __, blood is drawn from the patient’s body and passed through a dialyzer, which is a devise composed of a semipermeable membrane, and connected to a machine that controls the flow of blood, the pressure and temperature.

Soap

lowers the surface tension of water by disrupting the cohesive forces between the water molecules at the surface.

Hypertonic salt solution

has a higher solute concentration that the inside of the red blood cell. In this case, water will move out of the cell and into the surrounding solution to equalize the solute concentrations on both sides of the cell membrane. This will cause the red blood cell to shrink and lose its normal biconcave shape.

cell lypsis

cell loses too much water

hypotonic salt solution

has a lower solute concentration than the inside of the red blood cell. in this case, water will move into the cell and swell it up, potentially causing the cell to burst by increasing the pressure inside the cell.

Isotonic salt solution

has a solute concentration equal to the inside of the red blood cell. in this case, no net movement of water into or out of the cell, and the red blood will maintain its normal shape and volume.

Presence of carbon

Charring of powdered egg albumin

Presence of hydrogen and oxygen gas

formation of water vapor at the sides of the test tube

presence of nitrogen in the form of ammonia gas

red litmus paper turns blue

presence of sulfur

filter paper with lead acetate turns black (PbS)

Biuret test

Results to bluish to purple color which indicates the presence of peptide linkage in polypeptides except in dipeptides

Ninhydrin reaction

Results to violet to blue color which indicates the presence of alpha amino group.

Xanthoproteic reaction

Results to yellow to orange color which indicates the nitration of benzene in phenylalanine, tyrosine, and tryptophan

Hopkins-Cole Test

Results to violet ring at the junction which indicates the indole ring in tryptophan

Millon’s test

Results to flesh to red precipitate which indicates the phenol group in tyrosine

Gluten

is a structural protein naturally found in certain cereal grains. It acts like a binder, holding food together and adding a ‘stretchy’ quality.