mcq biology

Biology MCQ-04 Biochemistry: Carbohydrates – Part 3 for JRF/NET Life Science Examination

Biology MCQ (Multiple Choice Questions in Life Science)
(Sample/Model/Practice Questions for JRF/NET Life Science Examination, ICMR JRF, DBT JRF, GATE, ICAR NET, PG Entrance)


Biochemistry: Carbohydrates Part 3 (MCQ 04)


1. Which of the following is an example for a trisaccharide?

a.       Verbascose
b.      Stachyose
c.       Raffinose
d.      Sucralose

2. Chrysolaminarin is ________.

a.       A storage polysaccharide of green algae
b.      A storage polysaccharide of brown algae
c.       A storage polysaccharide of red algae
d.      A storage polysaccharide of diatoms

3. Which of the following is an example for an artificial sweetener of saccharide origin?

a.       Sucralose
b.      Saccharin
c.       Stachyose
d.      All of these

4. In a chemical reaction ‘X’ is able to convert Cu2+ ions to Cu+ ions. If ‘X’ is a carbohydrate, which of the following best explains to be the ‘X’?

a.       ‘X’ is a reducing sugar
b.      ‘X’ is a non-reducing sugar
c.       ‘X’ is a monosaccharide
d.      Both (a) and (b)
e.       Both (a) and (c)

5. Which of the following is a reducing sugar?

a.       Glucose in closed ring form
b.      Glucose in open chain form
c.       Sucrose

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mcq biology

Biology MCQ-03 Biochemistry: Carbohydrates – Part 2 for JRF/NET Life Science Examination

Biology MCQ (Multiple Choice Questions in Life Science)
(Sample/Model/Practice Questions for JRF/NET Life Science Examination, ICMR JRF, DBT JRF, GATE, ICAR NET, PG Entrance)


Biochemistry: Carbohydrates Part 2 (MCQ-03)


1.  The vitreous humor of eye is composed of_______.

a.       Heparin
b.      Hyaluronic acid

c.       Keratan Sulfate
d.      Chondroitin sulfate

2. N-acetyl glucosamine (NAG) and N-acetyl muramic acid (NAM) in peptidoglycan is connected by ____glycosidic linkage.

a.       α 1 – 4
b.      β 1 – 4

c.       α 1 – 2
d.      β 1 – 2

3.  Sulbactam is a ____________.

a.       β-lactam antibiotic
b.      β lactamase

c.       β lactamase inhibitor
d.      A class of penicillin

4.  Which of the following is not a sugar molecule of the O-antigen of gram negative bacteria?

a.       Tyvelose
b.      Abequose

c.       2 keto-3-deoxyoctanoate
d.      Teichoic acid

5.  Glycosidic bond between galactose and glucose in lactose is____.

a.       α 1 – 4
b.      β 1 – 4

c.       α 1 – 2
d.      β 1 – 2

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mcq biology

Biology MCQ-02 Biochemistry: Carbohydrates – Part 1 for JRF/NET Life Science Examination

Biology MCQ (Multiple Choice Questions in Life Science)
(Sample/Model/Practice Questions for JRF/NET Life Science Examination, ICMR JRF, DBT JRF, GATE, ICAR NET, PG Entrance)


Biochemistry: Carbohydrates Part 1 (MCQ-02)


1. The general chemical formula of carbohydrate is

a.       (CH2O)n
b.      (CH2O)2n

c.       (CHO)n
d.      CnH2nO

2. Which of the following is an aldotriose?

a.       Dihydroxyacetone
b.      Glyceraldehyde

c.       Ribulose
d.      Erythrose

3. What is the molecular formula of sucrose?

a.      C12H22O11
b.      C10H20O10

c.       C6H12O6
d.      C12H20O11

4. The glycosidic linkage between glucose molecule in maltose is

a.      β 1 – 4
b.      α 1 – 2

c.       α 1 – 4
d.      β 1 – 2

5. A keto pentose will have _____ sterioisomers.

a.      4
b.      6

c.       8
d.      10

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biological chemistry

Biochemistry of Plasma Membrane Lipids: Properties, Structure and Classification (Biochemistry Lecture Notes)

PLASMA MEMBRANE LIPIDS
Biochemistry, Properties, Structure and Classification of Lipids of Plasma Membrane

 “Good fences make good neighbors”
Robert Frost, “Mending Wall”, 1914


Biological membrane system: Biological membranes are highly dynamic two layers thick sheath like structures formed by the non-covalent assemblage of lipids, proteins and carbohydrates. They form closed boundaries between different compartments of the cells such as separation of nucleoplasm from the cytoplasm by nuclear membrane in all eukaryotes. They act as barriers to the passage of polar molecules and ions. The thickness of membrane varies among different classes of organisms and the average width ranges from 60 Å (6 nm) to 100 Å (10 nm) in most of the cases.

Even though membrane contains carbohydrates and proteins, the major structural components of bio-membrane are a special class of lipids called membrane lipids. In storage lipids (triglycerides) the three –OH groups of glycerol moieties are esterified by three fatty acids and thus they are completely non-polar. However in membrane lipids, the hydroxyl group at C1 and C2 are esterified with fatty acids and the remaining third –OH group (at C3) will combine to a polar molecule. Thus membrane lipids are amphipathic because they have hydrophilic head (polar) at one end and hydrophobic tail (nonpolar) at the other end. The long hydrocarbon chain of fatty acids forms the hydrophobic part. The hydrophilic moieties of membrane lipids are of different types and which may be as simple as –OH or may be much complex like carbohydrates or amino acids or their derivatives. We commonly call the polar part of membrane lipid as ‘Head’ group and the nonpolar part as ‘Tail’ group.

easybiologyclass, membrane lipid: polar head and non-polar tail group

easybiologyclass, plasma membrane structure and organization, lipid bi-layer of plasma membrane.

The hydrophobic interactions of the nonpolar parts among themselves and the hydrophilic interaction with water are responsible for the packing of lipids in the membrane. These hydrophilic and hydrophobic interactions are also responsible for the bilayer organization of membranes in the cells.

Classification of membrane lipids:

Membrane lipids are classified based on the properties of ‘Head’ group. The membrane lipids of Prokaryotes, Eukaryotes and Archaebacteria are grouped into four major categories:

.

1.   Phospholipids

2.   Glycolipids

3.   Sterols

4.   Archaebacterial ether lipids

 easybiologyclass, mind map membrane lipid classification chart

.

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biological chemistry

Why the pH of water is 7

Biochemical Principle Behind pH Scale and pH of Water
(The Relationship Between Equilibrium Constant, Ion Product of Water and pH Scale)


pH is defined as the negative logarithm of hydrogen ion concentration in a medium. For example, if you are saying a solution with pH 6.5, it means that the concentration of H+ ions in that solution expressed in negative logarithmic term is 6.5. pH is a scale, a scale to measure the H+ ion concentration in a medium. The pH scale starts from 0 to 14. The middle value in the scale (7) is considered as a neutral pH and any solution with pH below 7 is considered as acidic pH. Similarly any solution with pH above 7 is considered as a basic solution. Like the Celsius temperature scale, the pH scale is also constructed on the basis of water, the universal solvent and also the solvent of life.

pH of water is 7 and it is considered as a neutral pH. The term neutral does not mean that water does not contain H+ ions. In fact the term neutral means water contains equal number of H+ and OH- ions. Everyone knows that the pH of water is 7 and it is a neutral pH. But people often forgot to think why the pH of water is 7; from where the value 7 comes… is it a randomly assigned value to water? No, not at all.., the value 7 is an absolute value derived from the ion product of water. The ion product (the product of ions in water i.e., product of H+ and OH-) of water thus forms the basis of pH scale. The video tutorial explains how water got the pH value 7 and how the ion product of water is related to pH scale.

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