Labs Flashcards
What is special about protein interaction with its ligand?
specificity which is accomplished by an extremely precise and complementary interaction between a signal and its receiver
Specificity of the enzyme is due to
Their structure
Influence of temperatures on enzyme activity
High temperatures->denaturing
Low temperatures-> inactive, but not permanently denatured
Lactose has been shown to aid the absorption of
Calcium
Magnesium
Zinc
The gene for the production of lactase is located on
Chromosome 2
What is the difference between the person with lactose intolerance and without
Not DNA difference, but the difference in the messenger RNA
Predominant sugar in cow’s milk
Lactose
Predominant sugar in soy milk
Sucrose
Predominant sugar in rice milk
Glucose
At what pH and temperature lactase was the most efficient
The optimal temperature for lactase is 37̊C and pH range of 4-9
What happened with lactase when exposed to boiling for 1 hour or to pH 2 and pH 12
High temperature and pH outside the optimal pH range disrupted intra- and intermolecular forces (e.g. hydrogen bonds) that hold the quaternary, tertiary and the secondary structure of the enzyme, which allows the tight bonding between the substrate and the enzyme, making the enzyme ineffective.
Sugars in lactose and the bond connecting it
Lactose is a disaccharide Lactose is the result of condensation reaction between two monosugars: D-galactose and D-glucose, which are connected by beta 1-4 glycosidic linkage.
Lactose has ___
a reducing end
Characterization of glucose and galactose
aldohexose and they are epimers at C-4.
What is the name of the reaction breaking down lactose
Hydrolysis
Hydroxyl group is added on the first carbon in D-glucose and hydrogen to oxygen on carbon 4 in D-galactose.
Why lactase cannot break other sugars
Lactase can hydrolyze only β-1-4-glycosidic bond between D-galactose and D-glucose. To bind to its substrate, lactase recognizes hydroxyl groups on carbon 2 and 3 on the galactopyronase moiety in lactose. Thus, it cannot hydrolyze sucrose, for instance, because this disaccharide consists of fructose and glucose molecules with 2β α1 linkage.
After exposing lactase to different temperatures, when the glucose level rose after the waiting period and why
The glucose concentration rose when ice treated lactase combined with lactose stayed at room temperature for 30 minutes. Initially, the temperature for the enzyme activity was very low and the reaction occurred at very slow rate. The test for free glucose level was negative. When the test tube remained at room temperature for some time, the activity of the enzyme increased, as the molecule movement and the collision between the substrate and the enzyme became more frequent.
The tube with room temperature lactase
Lipids include
oils, waxes, phospholipids, steroids (like cholesterol), and some other related compound
Solubility of fat
Hydrophobic
But dissolve in fat solvents:hexane or acetone
Lipids break into ___ when hydrolyzed with alkali like NaOH
Glycerol and FAs
The process of breaking down lipids into FAs, glycerol and producing sodium salts of FAs is called
Saponification, production of salt
Saturated fats are coming from __
Animal sources
Why saturated fat is solid at room temperature?
Its tails are straight and it can pack together
How can you discover the degree of bond saturation
A halogen solution such as iodine and bromide-> the extend of decolourization
What is iodine number
The more double bonds a fat contains, the more halogen is required; thus, a high iodine number means a high degree of unsatu
How can you determine the length of FAs
Differences in chain length can be distinguished by the differences in intensity of colour due to the absorption of a chemical known as Sudan III. Longer fatty acid chains give more intense and deeper colour
H2O,Soap,NaoH,EtOH,Acetone,Chloroform: fat miscibility
Do not mix with water
Mix with ethanol,acetone,soap,chloroform,NaOH
How to count saponification number
Mol of KOH in the solution*(HCL used for titration-ml(blank) -HCL used for titration-test)->Mol of KOH reacted
Mol KOH56.110^3->saponification number
What type of soap produced jojoba and coconut is hard/soft
Jojoba-soft
Coconut- hard
Why oil did not mix with water
. Water does not mix with oil and stay separate from it, because it is thermodynamically favorable. As oil and water has two different kinds of bonds and the intermolecular forces in oil (the London dispersion force) is weaker and do not have enough energy to mix with high energy water molecules. Water is more attracted to each other because of hydrogen bond-dipolar interactions.
How the soap does its job
The dirt is a hydrophobic particle that dissolves in oil. Oil and water do not mix together, making the dirt hard to wash off. The soap has both a hydrophobic tail (an aliphatic chain) and a hydrophilic head (carboxylate group). This dual nature allows the soap mix well with both water and oil and from micells.
What is the job of phenyalalnine and how does it turn form pink to colorless
Phenolphthalein is a chemical that is used to determine the pH of the solution. In the basic environment it turns pink. It changes the color to transparent in the acidic environment. The change of the color is the process called ionization. During this process the molecule loses or gain electrons. In the case of phenolphthalein, ionization results in conformational change, when added to alkaline solution. Usually, phenolphthalein is colorless, because it allows the light to come through. But when added to the basic solution, OH- takes off hydrogen from phenolphthalein (and electron as well), changing the shape and thus resulting in color change to pink.
The primary and the secondary role of carbohydrates
Source of energy
Intermediate source of energy (starch and glycogen)
Sucrose is a disaccharide of
Glucose and fructose
Major source of carbohydrates for humans are
Starch and sucrose
Connectivity in glycogen
1-4 alpha
1-6 alpha
Benedict’s test is for
The detection of the presence of reducing sugars.
Reducing sugars have either ___ or ___
Free aldehyde group or free ketone group
What are the components of Benedict’s solution and how the reaction happens
Benedict’s solution is the mixture of copper sulfate, sodium citrate, and sodium bicarbonate, which is used to determine the reducing end in sugars. Sodium citrate keeps Cu2+ in the solution, which otherwise would precipitate. Sodium bicarbonate provides an alkaline environment, required for the redox reaction to occur. The color of Benedict’s solution is blue due to the presence of Cu2+. In the hot alkali environment, upon addition of sugar that has a free aldehyde group or a free ketone group (reducing sugars), the color of the solution changes its color to red brick due to cuprous oxide (Cu2O). When combined with sodium bicarbonate and heated, a reducing sugar is converted to enediols, a molecule with two adjacent hydroxyl groups to the double bond. Enediols react with Cu2+ in Benedict’s solution to form Cu2O.
Glucose is what sugar, the same for fructose, xylose and sucrose
Glucose is an aldohexose reducing monosaccharide. Fructose is a ketohexose reducing monosaccharide. Sucrose is not a ketose or aldose, because it is a disaccharide. Also, sucrose is a non-reducing hexose sugar. Xylose is an aldopentose reducing monosaccharide
Bial’s reagent is used to detect
For pentoses
The content of Bial’s reagent and indication of the positive result, how the reaction happens
Bial’s reagent is the solution of orcinol, concentrated hydrochloric acid and ferric chloride. In an acidic medium with the presence of heat, pentoses form furfural molecule, which in turn reacts with orcinol and ferric ion to from bluish product. This product gives the solution its color, indicating positive results for the presence of a pentose sugar. When a hexose is put into Bial’s solution and heated, 5-hydroxy-furfural is formed, which then reacts with Fe3+ and orcinol, resulting in green or yellow color.
Seilwanoff’s test is used for
A test for ketoses
The content of Seilwanoff’s reagent and how the reaction happens and what is the positive reaction
Seilwanoff’s reagent consists of resorcinol and hydrochloric acid. When sugar is added to the reagent and heated, hydrochloric acid hydrolysis poly- and disaccharides to monosaccharides and then converts ketoses to 5-hydroxymethylfurfural. The latter reacts with resorcinol within 5 minutes to give a deep red wine color. Aldoses undergo the same reactions but more slowly.
Molish’s test is used for
detection of mono, di, poly saccharides
Components of molish’s reagent and what happens
Molisch’s reactant is 1-naphthol dissolved in ethanol. All sugars will give a positive result to Molisch’s reactant. When the reagent is combined with sugars and sulphuric acid is added gradually to form a layer on top, the acid dehydrates hexoses to 5-hydroxymethylfurfural and pentoses to furfural. Also, the acid breaks di- and polysaccharides into smaller subunits. Furfural reacts with 1-naphthol, resulting in a purple product. As di- and polysaccharides need an extra step of breaking down before to be converted to furfural, monosaccharides will form a purple band faster than di- and polysaccharides.
What cow has the highest amount of sugar in the blood: lactating, heifer,pregnant
Heifer is the highest, then pregnant and then peak lactation
Chromotography is used to
Separate mixtures of substances into their components
What was the stationary phase and the mobile phase in the experiment
Stationary phase: water and nitrocellulose
the mobile phase is a solvent, which consists of 72% Propanol, 8% Acetic Acid and 20% dH2O
What is important with the solvent level and the line where amino acids were put
The solvent should be below this line
why we covered the beaker with the aluminum foil where chromotography was
To saturate with vapor-> rise more quickly
What is done in the end of the experiment so we can see AAs
When the solvent has migrated almost to the end, the paper is dried and sprayed by ninhydrin solution. At 100°C, ninhydrin reacts with α-amino acids to form a purple colour, allowing the amino acids to be visualized
How to count Rf
Distance traveled by compound/distance traveled by solvent
What AAs travel the highest and the lowest
Least to highest
Lysine, aspartic acid, glutamic acid, phenyalalnine, isoleucine
Diet Pepsi had what sugar
Aspartame= aspartic acid and phenylalanine
Gel electrophoresis is used for
or the separation of deoxyribonucleic acid, ribonucleic acid, or proteins using an electric current applied to a gel matrix
Why it is called electrophoresis
Electrophoresis” refers to the electromotive force (EMF) that is used to move the molecules through the gel matrix. By placing the molecules in the gel and applying an electric current, the molecules will move through the matrix at different rates, usually based on size. Nucleic acids have a net negative change and move from negative electrodes located near the top of the gel to positive electrodes at the bottom of the gel. Movement is based on charge and size
The migration rate of the fragment in gel is inversely proportional to
the log10 of their size
What is gel in electrophoresis and example of one of those and how it is made
el is a cross linked polymer whose composition and porosity is chosen based on the specific weight and composition of the target to be analysed. One example of gel usedto separate nucleic acidsis Agarose. Agarose isa long chain polysaccharideisolated from seaweed. Itis heated in a buffer solution and then cooled it forms a matrix (gel) with buffer solution trapped inside. This gives rise to a porous lattice in the buffer solution which enables nucleic acidmolecules to slip through the lattice holes in order to move toward the positive pole
Characteristics that influence the travelling capacity of the nucleic acid
conformation, charge, size
Aragose size can changed from 0.5 to 2%, influencing
ges. Higher percentage gels have smaller pores which retards nucleic acidsmovement. High percentage gels are excellent for allowing the separation of small fragments of nucleic acidand lower percentage gels are typically used to separate larger fragm
What is the comb
fragments. A “comb” is used to create wells in the gel to allow for the loading of nucleic acids. These wells are small grooves in the gel where the nucleic acidis placed before running the gel to hold it in place. The well size determines how much of the nucleic acidsample can be loaded.
The most common buffer for electrophoresis
Tris Bonate EDTA
Why do we need EDTA
The Trismaintains a slightly basic condition (pH 7.3). EDTA prevents enzymatic degradation of nucleic acids as it chelates magnesium ion
What does loading dye has and the purpose of it
g glycerol and tracking dyesis mixed in with the nucleic acid sample.The high density of glycerol aids the nucleic acid solution in settling in the well when loading. The dye moves more quickly than the nucleic acids and allows tracking the movement of the fragments. It is used as an indicator to alert the researcher to turn off the power.
Makes the solution more visible, to make the handling of the solution easier
The use of ethidium bromide and the precaution
. Ethidium bromide is commonly used in molecular biology laboratories for visualizing nucleic acids using electrophoresis and other gel-based nucleic acid separation methods. Ethidium bromide fluoresces when exposed to ultraviolet light and exhibits a vivid red-orange color when bound to nucleic acids.UV-transilluminator are usedto visualize the nucleic acidbands after running the gel.Ethidium Bromide however is quite dangerous to use as it is a carcinogenand a mutagen.
We tested the chromosome of what species and what gene
Gallus gallus
CHD-1
What is PCR
PCR, or polymerase chain reaction, is a method used for amplifying of a specific DNA region in a test tube. Taq Polymerase, primers that are complementary to the DNA sequence of interest, DNA, nucleotides together with cofactors required for the enzyme function are put in the test tube and are subjected to cycles of cool and hot temperature that allow DNA to be multiplied.
Explain how PCR is performed
The first step is to expose the solution to 96 ̊ C, so DNA strand denature and single DNA strands would be available. The second step is to cool the solution to 55-65 ̊ C, so the primers can bind to the complementary sequence on single-stranded DNA. Finally, the solution is heated to 72 ̊ C, so the extension by Taq polymerase of the required DNA sequence occurs more quickly. The cycle is repeated 25-35 times.
Why do we use Taq polymerase and what is it
Taq Polymerase is a DNA Polymerase that was excreted from heat-tolerant bacterium Thermus aquaticus. This species can be found in hydrothermal vents and hot springs. Its DNA Polymerase is heat-stable and has peak activity at 70 ̊ C
