BIO303 Final Term Mega File by Biotech Brainy Bunch

Final Term Subjective Current + Past questions

Q1. Glycolysis?

Glycolysis is a cytoplasmic pathway which breaks down glucose into two three-carbon compounds and generates energy. Glucose is trapped by phosphorylation, with the help of the enzyme hexokinase. Adenosine triphosphate (ATP) is used in this reaction and the product, glucose-6-P, inhibits hexokinase.

Q2. Why pure water carries current?

Pure water contains electrical current because 𝐻3𝑂+ migrates towards the cathode and O𝐻− towards anode.

3. First order reaction? OR

What is the first order reaction in terms of substrate?

For the uni molecular reaction S → P, the rate (or velocity) of the reaction, V—representing the amount of S that reacts per unit time—is expressed by a rate equation: V = k[S]. An equilibrium such as S ↔ P is described by an equilibrium constant, Keq, or simply K.

Bio303 - FINALTERM SUBJECTIVE MEGA FILE · GROUP: BIOTECH BRAINY BUNCH · ALL DATA FROM PAST PAPERS · ADMINS: MEHWISH MUGHAL & BELLA

Under the standard conditions used to compare biochemical processes, an equilibrium constant is denoted K ́eq (or K ́). In this reaction, the rate depends only on the concentration of S. This is called a first-order reaction. he factor k is a proportionality constant that reflects the probability of reaction under a given set of conditions (pH, temperature, and so forth).

Q4. Source of fatty acids in cells?

To utilize acetate from fat for biosynthesis of carbohydrates, the glyoxylate cycle, whose initial reactions are identical to the TCA cycle, is used. This pathway thus allows cells to obtain energy from fat. The oxaloacetate can be converted into Phosphoenolpyruvate, which is the product of phosphoenol pyruvate carboxykinase, the first enzyme in gluconeogenesis.

Q5. Advantages of using triacylglycerol as storage source?

1. Fats are highly reduced hydrocarbons with a large energy of complete oxidation (38 kJ/g) more than twice that for the same weight of carbohydrate or protein.
2. Fats are chemically inert (triglycerides or neutral fats)

that make them especially suitable as storage fuels so they can be stored without fear of unfavorable reactions.

3. Fats are insoluble molecules that aggregate into droplets.

Q6. Function of coenzyme A in pyruvate dehydrogenase?

Coenzyme A (CoA, sometimes denoted CoA-SH, to emphasize the role of the OSH group)

Coenzyme A (CoA). A hydroxyl group of pantothenic acid is joined to a modified ADP moiety by a phosphate ester bond, and its carboxyl group is attached to b-mercaptoethylamine in amide linkage. The hydroxyl group at the 3’ position of the ADP moiety has a phosphoryl group not present in free ADP.

The —SH group forms a thioester with acetate in acetyl-coenzyme A (acetyl-CoA).

7. How water ionize and what happens to hydrogen ions? OR

Which ions are formed due to ionization of water.? and what happens to H+ ions?

Water molecule have a slight tendency to undergo reversible ionization to yield a hydrogen ion (a proton) and a hydroxide ion, giving the equilibrium reaction. Hydrogen ion formed in water

Q8. How malate synthase throw light on evolutionary history of glyoxylate?

In recent years, the detection of malate synthase (MS) and isocitrate lyase (ICL), key enzymes involved in the glyoxylate cycle, in some animal tissue has raised questions regarding the evolutionary relationship of enzymes in bacteria and animals and suggests that animals encode alternative enzymes of the cycle that differ in function from known MS and ICL in nonmetazoan species. Isocitrate lyase and malate synthase are unique to the glyoxylate cycle. Notice that two acetyl groups (light red) enter the cycle and four carbons leave as succinate (blue).

Q9. Enzyme kinetics when enzyme concentration is less than substrate?

A numerically large (high) Km reflects a low affinity of enzyme for substrate because a high concentration of substrate is needed to half-saturate the enzyme.

Q10. Define pH? Derived its equation. Explain in terms of water pH at 25℃?

pH: The pH of a solution is defined as the logarithm to the base 10 of the reciprocal of the [H+], i. e, the negative logarithm of the [H+].

Equation:

Designates the H+ and OHConcentrations

pH = log 1/[H+]

pH = -log[H+]

For each pH unit less than 7.0, the [H+] is increased tenfold.

for each pH unit above 7.0, it is decreased tenfold.

Water pH at 25℃:

The pH of water at 25°C, in which H+ and OH– ions are present in equal numbers, is 7.0

pH = -log[1 x 10-7]= 7

The symbol p denotes "negative logarithm of"