1. Which of the following viruses is found in saliva?
a) HIV
b) Dengue virus
c) Hepatitis B virus
d) Epstein-Barr virus (EBV virus)
Explanation: Epstein-Barr virus or EBV is also known as Herpes virus 4. It causes an infection called Mononucleosis, which is a contagious disease. Since the virus is present in the saliva of the host, it can be contracted by a healthy individual by kissing or eating from the same utensils.
2. How many structural and non-structural proteins are there in the dengue virus?
a) 7 ; 2
b) 3 ; 8
c) 3 ; 7
d) 3 ; 9
Explanation: Dengue virus has 3 structural or surface proteins namely the Capsid protein (C), the Membrane protein (M) and the Envelope protein (E). It also has 7 non-structural proteins (NS proteins) namely NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5.
3. Which of the following is released when a Hydrogen atom loses an electron?
a) Nucleus
b) Proton
c) Charge
d) Ion
Explanation: Whenever a hydrogen atom releases a shared electron in solution, a proton is also released. For example, acetic acid undergoes dissociation reaction to release acetate ion and a proton.
4. Which of the following is an example of amphoteric molecule?
a) Acetic acid
b) Malic acid
c) Sugars
d) Water
Explanation: Water is an example of both an acid and a base, and is therefore an amphoteric molecule. It can accept a proton thereby acting as a base and can also donate a proton acting as an acid.
5. Acids that lose a proton easily are weak acids.
a) True
b) false
Explanation: The strength of an acid is measured by the relative ease by which it loses a proton. The more readily the proton is lost, more strong is the acid. An example of a strong acid is Hydrogen Chloride which readily transfers its protons to water.
6. What is the full form of pH?
a) Positive hydrogen
b) Potential Hydrogen
c) Positron
d) Proton of hydrogen
Explanation: The acidity of a compound is measured by the concentration of hydrogen ions and is expressed in terms of pH- potential hydrogen. pH equals negative logarithmic concentration of protons.
7. A solution having a pH of 6 has a proton concentration of _______
a) 10-6 M
b) 106 M
c) 6 M
d) 0.6 M
Explanation: pH equals negative logarithmic concentration of protons. Since the pH scale is logarithmic, an increase of one pH unit corresponds to ten-fold decrease in hydrogen ion/ proton concentration.
8. What is the concentration of pure water?
a) 55.51 M
b) 25.51 M
c) 55 M
d) 25 M
Explanation: The concentration of pure water is always 55.51 Molar. On the basis of this universal value ion-product constant Kw for water is calculated, which is a constant value at 25℃.
9. In presence of an acid, amino group can be ____________
a) Polarized
b) Washed away
c) Protonated
d) Replaced
Explanation: In presence of an acid, amino group can be Protonated because an acid release proton, thereby increasing the hydrogen ion concentration in its vicinity and this can result in disruption of the protein activity to which amine group is attached.
10. Buffers react with _______________ ions.
a) hydrogen, hydroxyl
b) magnesium, calcium
c) potassium
d) sodium
Explanation: Buffers react with free hydrogen and free hydroxyl ions resisting changes in the pH and protecting cells and solutions from destroying. Buffers are also routinely used in laboratories.