Question

24. Which of the following was a crucial difference between the work of John T. Needham and Louis Pasteur on the question of spontaneous generation?

A. Whether or not the infusions were boiled

B. Whether or not the flasks were sealed

C. Whether meat or infusions were used

D. The length of time the flasks were boiled

E. The method of sealing the flasks

69. Which of the following is NOT a function of the bacterial cytoskeleton?

A. construction of a dividing cell

B. directing deposition of NAM & NAG molecules

C. localizing ribosomes in the cytoplasm

D. determining the location of the DNA

E. a form of motility

71. Which of the following is CORRECT about bacterial ribosomes?

A. They have two subunits and contain three RNA molecules

B. They are a single complex without subunits, and contain three RNA molecules

C. They have three subunits each containing an RNA molecule

D. They have two subunits, the smaller one composed of protein only, and the larger one composed of RNA only

E. They are a single complex containing one large RNA molecules and several proteins

72. An external structure unique to the archaea is a(n) :

A. cilium

B. flagellum

C. fimbria

D. hamus

E. pilus

79. Which of the following is paired INCORRECTLY?

A. plants; cellulose cell wall

B. algae; chitin

C. bacteria; peptidoglycan

D. fungi; polysaccharide cell wall

E. archaea; protein cell wall

92. A phosphate is moved from one molecule to another. This is an example of a/an ________ reaction.

A. anabolic

B. catabolic

C. endothermic

D. exchange

E. exothermic

96. Amino acids can combine with either hydroxyl or hydrogen ions. As a result, they can function as ________.

A. transfer groups

B. buffers

C. solvents

D. cations

E. salts

97. Which of the following is NOT a characteristic of saturated fats?

A. they are usually solid at room temperature

B. they contain at least one double bond

C. they are found in animals

D. their fatty acids pack tightly together

E. they are a form of stored energy

98. Which of the following is NOT a characteristic of phospholipids?

A. they are found in cellular membranes

B. they can form micelles and bilayers

C. they contain fatty acids that associate with water

D. they contain a hydrophilic phosphate "head"

E. they contain two fatty acids and a phosphate functional group

Answer 1

24. The following was a crucial difference between the work of John T. Needham and Louis Pasteur on the question of spontaneous generation:

B. Whether or not the flasks were sealed

While boiling, Needham's flask were sealed, while Pasteur used a swan necked flask to trap any air borne organisms and prevents its entry into the infusion. The mouth of the swan neck, however was left open to allow passage of air.

D. The length of time the flasks were boiled

Pateur boiled his flask containing broth long enough to kill any residual micro organisms. Needham however failed to heat the flask long enough to kill all residual micro organisms and hence came to the incorrect conclusion that life can be generated spontaneously.

E. The method of sealing the flasks

As mentioned earlier, Needham's flask was completely sealed while Pasteur allowed the passage of air but not micro organisms using a swan neck.

These options are incorrect because:

A. Whether or not the infusions were boiled

Infusions or broth were boiled in both experiments. What differed was the time it was boiled for.

C. Whether meat or infusions were used

In both cases, infusions were used. Meat was used in Redi's experiment.

69. The correct answer is:

B. directing deposition of NAM & NAG molecules

Movement of molecules within cell to the cell wall is directed by carrier proteins and not cytoskeleton. Hence deposition of NAM and NAG in bacterial cell wall is not a function of cytoskeleton.

The other options are incorrect because:

A. construction of a dividing cell

Cytoskeleton provides a framework for the cell and helps maintain its shape. It guides the movement of genetic material and other cell organelles during cell division.

C. localizing ribosomes in the cytoplasm

Cytoskeleton maintains a framework and thereby guides the movement of cell organelles. Therefore it helps in localizing ribosomes in cytoplasm.

D. determining the location of the DNA

Cytoskeleton plays important part in DNA partitioning in bacteria.

E. a form of motility

Cytoskeleton is formed of a network of actin and microtubule filaments. These are also the constituent units of cilia and flagella and their movement is guided by the cytoskeleton.

71. The following is CORRECT about bacterial ribosomes:

A. They have two subunits and contain three RNA molecules

Bacterial ribosomes is 70S and have two subunits, 50S and 30S. 50S is composed of 23S and 5S RNA, while the 30S subunit contains 16S RNA.

Thus, the following options are incorrect.

B. They are a single complex without subunits, and contain three RNA molecules

It has two distinct subunits - 50S and 30S, and not a single one.

C. They have three subunits each containing an RNA molecule

It has only two subunits, 50S with 2 and 30S with 1 RNA molecule.

D. They have two subunits, the smaller one composed of protein only, and the larger one composed of RNA only

The smaller subunit 30S, has 16S RNA alongside 21 proteins, while the larger subunit 50S has 23S and 5S RNA and 31 proteins.

E. They are a single complex containing one large RNA molecules and several proteins.

It has 2 subunits and 3 RNAs so this statement is false.

72. An external structure unique to the archaea is a:

D. hamus

Hami (plural of hamus) are small filamentous cell surface appendages, present surrounding the archeal cell, which helps in the adhesion of cell to the surface.

The following are not unique to archea:

A. cilium

Cilium is found in bacterial cell as well as in cells of various organs in higher animals.

B. flagellum

Flagellum is a primary locomotory structure of bacteria and is found even in human sperm.

C. fimbria

Fimbria is found in bacteria as well and helps in cell adhesion.

E. pilus

Pilus too is abundant in bacterial cells.

79. The following is paired incorrectly:

B. algae; chitin

Chitin is the component of fungi cell wall as well as insect exoskeleton. Algae cell wall is made up of glycoproteins and polysaccharides like agar.

The following pairing is correct:

A. plants; cellulose cell wall

Plant cell wall is indeed made of cellulose.

C. bacteria; peptidoglycan

Bacterial cell wall is composed of peptidoglycan or murein.

D. fungi; polysaccharide cell wall

Cell wall of fungi is made of the polysaccharide chitin as well as glucans and glycoproteins.

E. archaea; protein cell wall

Archaea does indeed have a cell wall made of protein.

92. A phosphate is moved from one molecule to another. This is an example of an ________ reaction.

D. exchange

This reaction is simply an exchange reaction as it involves the transfer of a group from one molecule to the other.

The other options are incorrect because:

A. anabolic

Reaction is anabolic when smaller molecules combine to form a larger and more complex molecule, which is not the case here.

B. catabolic

A reaction is said to be catabolic when a large molecule is broken down into smaller ones. This is also not the case here.

C. endothermic & E. exothermic

Endothermic reactions are those that absorb heat or use up energy to occur, while exothermic reactions release heat on occurence. In molecules such as ATP, release of phosphate groups releases a large amount of heat and hence it is an exothermic reaction and uptake of phosphate by ADP loses heat. In the transfer reaction, net energy change will be zero, and heat will neither be released nor absorbed.

96. Amino acids can combine with either hydroxyl or hydrogen ions. As a result, they can function as ________.

B. buffers

Buffers help to control pH in a medium. As amino acids can combine with both hydrogen ions responsible for a low acidic and hydroxyl ions responsible for high basic medium, it can preferentially bind with one or the other to maintain a neutral medium.

These options are incorrect because:

A. transfer groups

Amino acid may act as transfer groups. But it is not because of its mentioned property.

C. solvents

Amino acids are not used as solvents typically.

D. cations

Amino acids remain in a zwitterionic form in neutral pH. On binding with H ions, it will form a cation and on binding with OH an anion. Also some amino acids also possess charged side chains already. They do not act as cation exclusively for this reason.

E. salts

Amino acids do not typically form salt. At a neutral pH, its positively charged amine group is balanced by negatively charged carboxyl group. On combination with H+ or OH- it will form either a cation or an anion, and not a salt.

97. The following is not a characteristic of saturated fats:

B. they contain at least one double bond

Saturated fatty acids do not contain any double bond by defination. It is the property of unsaturated fatty acids.

These options are the characteristics of saturated fats:

A. they are usually solid at room temperature

Saturated fatty acids have high melting point as compared to unsaturated fatty acids and thus exist as solid in room temperature.

C. they are found in animals

They are found in meat as well as dairy product.

D. their fatty acids pack tightly together

There are no kinks in saturated fatty acids in form of double bond which would repel neighboring chains. Hence fatty acids in saturated fat are closely packed together.

E. they are a form of stored energy

As compared to unsaturated fats, saturated fats can be tightly packed in close proximity and yield more energy during metabolism. Hence they are used as a form of stored energy.

98. The following is NOT a characteristic of phospholipids:

C. they contain fatty acids that associate with water

Fatty acids are inherently hydrophobic in nature and hence phospholipids cannot contain fatty acids that associate with water.

These are the characters of phospholipids:

A. they are found in cellular membranes

Phospholipid bilayer is the charecteristic feature of cell membranes.

B. they can form micelles and bilayers

As they contain hydrophobic fatty acid tails, in water, these tails aggregate together surrounded by hydrophilic phosphate heads in form of micelles and bilayers.

D. they contain a hydrophilic phosphate "head"

The phosphate group of phospholipids is indeed hydrophilic in nature and is referred to as the phosphate head.

E. they contain two fatty acids and a phosphate functional group

Each phopholipid molecule has teo fatty acid chains as tails and functional group of phosphate as the head.