Biochemistry Answers

A student is investigating the affect of different salts on melting points. Four patches of ice of equal size are roped off and a different type of salt is poured on each, one receives table salt (NaCl), one receives Calcium Chloride (CaCl2), one receives Potassium Carbonate (KCO3) and the fourth receives inert sand instead. Each patch receives an equal amount of salt or sand. The student measures the volume of ice remaining and subtracts it from the original volume of ice to see how much melted away. What is a control variable in this experiment?

. Treatment of a polypeptide by 2-mercaptoethanol yields two polypeptides that
have the following amino acid sequences:
X: Ala-Phe-Cys-Met-Tyr-Cys-Leu-Trp-Cys-Asn
Y: Val-Cys-Trp-Val-Ile-Phe-Gly-Cys-Lys
Chymotrypsin-catalyzed hydrolysis of the intact polypeptide yields polypeptide
fragments with the following amino acid compositions:
(Ala, Phe) (Asn, Cys2, Met,Tyr) (Cys, Gly, Lys) (Cys2, Leu,Trp2,Val) (Ile, Phe,Val)
Indicate the positions of the disulfide bonds in the original polypeptide. Cysteines are
numbered in order (C1, C2, C3 in X; and C4, C5 in Y).

The enzyme succinic dehydrogenase catalyses the conversion of succinate to
fumarate as given below. Which one of the following compounds would be a likely
competitive inhibitor of this reaction?
(COOH)H2C-CH2(COOH) → (COOH)HC=CH(COOH)
a. (COOH)HC=CH(COOH)
b. (COOH)C≡C(COOH)
c. CH3CH2CH2NH2
d. (COOH)-CH2-(COOH)
13. Treatment of a polypeptide by 2-mercaptoethanol yields two polypeptides that
have the following amino acid sequences:
X: Ala-Phe-Cys-Met-Tyr-Cys-Leu-Trp-Cys-Asn
Y: Val-Cys-Trp-Val-Ile-Phe-Gly-Cys-Lys
Chymotrypsin-catalyzed hydrolysis of the intact polypeptide yields polypeptide
fragments with the following amino acid compositions:
(Ala, Phe) (Asn, Cys2, Met,Tyr) (Cys, Gly, Lys) (Cys2, Leu,Trp2,Val) (Ile, Phe,Val)
Indicate the positions of the disulfide bonds in the original polypeptide. Cysteines are
numbered in order (C1, C2, C3 in X; and C4, C5 in Y).

Often the specific amount of a drug to be administered must be calculated from a given dose in mg per kilogram of body weight. This assures that individuals who have very different body mass get the proper dose. If the proper dosage of a drug is 6.0 mg/kg of body weight, how many milligrams would a 210−lb individual need?

A certain type of immune system cell, the plasma cell or B cell, makes antibodies (a type of defensive protein) that are secreted from the cell. It is possible to trace the path of these proteins through the cell by labeling them with radioactivity. Please indicate the pathway these antibodies would take, starting from where they are made to the exit from the cell. Make sure to indicate each structure or organelle along the way.

How plant growth can be measured with high precision that hourly growth rates can be determined? Is a plant growing only in the day, the night, or during both? Which implications does it have regarding the partitioning of photoassimilates between starch and sucrose?

Research different sources of information and use them to describe and explain sources of infection, routes of transmission and entry of micro-organisms into the human body. You must ensure that the following key terms are used in your explanations :
Human reservoirs; animal reservoirs; non-living reservoirs; contact transmission; vehicle transmission; vector transmission; entry via oral cavity; entry via droplet and entry via body fluids.

What are the factors that affect the immune response ? Differentiate between the cellular and humoral immunity

Explain the following terms.
(i) Termination codons
(ii) Lac operon
(iii) Chemical carcinogens
(iv) Immobilized enzyme

What is the difference between the electron transport reactions of mitochondria and the ones which take place in photosynthetic process ?