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Cell

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The most abundant chemical in the plasma membranes of prokaryotes is

  1. phospholipids

  2. proteins

  3. carbohydrates

  4. sterols

  5. peptidoglycan


Correct Option: A
Explanation:

Prokaryotic plasma membrane contains phospholipids as the major component.

Which of the following cell organelles is a single membrane-bound cell organelle found only in animals?

  1. Lysosome

  2. Peroxisome

  3. Vacuole

  4. Chloroplast

  5. Mitochondria


Correct Option: A
Explanation:

Lysosomes are the single membrane-bound organelles found only in animal cells. They have acidic pH and acid hydrolases enzymes that perform degradative function.

Plant cells contain all of the following structures, except

  1. vacuole

  2. mitochondria

  3. peroxisomes

  4. cell wall

  5. chromatophores


Correct Option: E
Explanation:

Chromatophores are absent in the plant cells as these are the specialised photosynthetic structures present in the cyanobacteria and photosynthetic bacteria only.

The cell orgenelles that protect other organelles of the cell from the toxic effects of H2O2 are__________.

  1. smooth endoplasmic reticulum

  2. lysosomes

  3. vacuoles

  4. mitochondria

  5. peroxisomes


Correct Option: E
Explanation:

Peroxisomes are single membrane bound cell organelles that contain oxidases and catalases enzymes. The enzyme catalases protects other cell organelles from the toxic effects of H2O2 by converting it into water and oxygen.

Which of the following processes is not common to both prokaryotes and eukaryotes?

  1. Active transport

  2. Simple diffusion

  3. Osmosis

  4. Passive transport

  5. Group translocation


Correct Option: E
Explanation:

Group translocation does not occur in eukaryotic cells. They perform endocytosis as an alternative mechanism whereas endocytosis is absent in prokaryotes. Therefore, group translocation is present only in prokaryotes.

Which of the following cell organelles in a plant share functional similarity with the lysosomes?

  1. Peroxisomes

  2. Vacuoles

  3. Chloroplasts

  4. Mitochondria

  5. Golgi complex


Correct Option: B
Explanation:

Vacuoles are the important cell organelles present in the plant cells. They usually consume about 30 percent of the cell’s volume. Vacuoles are important as they help in adjusting size and turgor pressure of the plant cells. Vacuoles are the cell organelles that share similarity with the lysosomes of animal cells as both contain degradative enzymes for breaking down macromolecules. In plants, vacuoles also serve as storage compartments for metabolites and nutrients.

Lysosomal enzymes work efficiently inside the lysosome because they

  1. work best at basic pH

  2. work best at neutral pH

  3. inactivate other enzymes

  4. resist basic pH

  5. work efficiently at acidic pH


Correct Option: E
Explanation:

All lysosymal enzymes work best at acidic pH and therefore they are known as acid hydrolases. They do not work efficiently at basic pH. The inside of the lysosome is maintained at 4.8 pH with the help of special hydrogen ion pump.

Which of the following cell organelles of an animal is most likely to get affected, if you treat it with streptomycin or erythromycin antibiotics?

  1. Cell wall

  2. DNA

  3. Lysosome

  4. Mitochondrion

  5. Chloroplast


Correct Option: D
Explanation:

Streptomycin and erythromycin are types of antibiotics that specifically act on the 70s ribosomes of prokaryotes and thus do not act on the 80S ribosomes of eukaryotic cells. However, mitochondrion contains 70 S ribosomes, it is most likely to get affected if it is treated with streptomycin or erythromycin antibiotic.

Which of the following statements related to a bacterial flagellum is incorrect?

  1. Bacterial flagellum rotates clockwise or counter clockwise from the basal body.

  2. The rotation of basal body causes the movement of flagellum in a bacterium.

  3. The basal body of flagellum in gram positive bacterium has two pairs of rings.

  4. A typical bacterial flagellum consists of three parts: filament, basal body and hook.

  5. Prokaryotic flagellum do not undulate in a wave like motion.


Correct Option: C
Explanation:

As gram positive bacterium lacks the outer lipopolysaccharide layer, the basal body of the flagellum in it has only the inner pair of rings and the outer pair of rings are absent in gram positive bacteria. Hence, this statement is not correct.

Which of the following chromosomes can be easily visualised under a light microscope?

  1. Early interphase chromosomes

  2. Late interphase chromosomes

  3. Prophase chromosomes

  4. Bacterial chromosomes

  5. Early prophase chromosome


Correct Option: C
Explanation:

Chromatin starts to condense and the chromosomes become visible microscopically, once this phase completes.

The structure of flagellum of a gram positive bacterium and a gram negative bacterium differs because of different

  1. protein arrangement

  2. cell wall structure

  3. cell membrane structure

  4. flagellin protein structure

  5. arrangement of flagella


Correct Option: B
Explanation:

Bacterial flagellum consists of three basic parts: the filament, hook and the basal body. The third part – basal body, is very important as it consists of several rings that anchor the flagellum into the plasma membrane and the cell membrane. A gram negative bacterium contains two pairs of rings that are attached to the different layers of the cell wall and the outer pair is specifically attached to the outer layer of the cell wall. As the outer cell wall is absent in a typical gram positive bacterial cell wall, it contains only the inner pair of rings that are inserted into the cell wall and plasma membrane. This structural arrangement of flagellum differentiates gram positive and gram negative bacterial cell’s flagella.

Which of the following chemical compounds is not found in the cell membrane of eukaryotes?

  1. Cholesterol

  2. Phospholipids

  3. Proteins

  4. Carbohydrates

  5. Muramic acid


Correct Option: E
Explanation:

Muramic acid is present in the bacterial cell wall and therefore it is not the constituent of plasma membrane.

Membrane proteins are produced_________.

  1. on smooth endoplasmic reticulum

  2. on the rough endoplasmic reticulum

  3. in the golgi complex

  4. in the DNA

  5. in the cytoplasm


Correct Option: B
Explanation:

Membrane proteins are produced on the rough endoplasmic reticulum and are carried forward with the help of membrane-bounded transport vesicles. Subsequently, these proteins are carried to the luminal cavity of the golgi complex, where they are processed.

Which of the following cells has less number of mitochondria?

  1. Muscle cells

  2. Brain cells

  3. Nerve cells

  4. Liver cells

  5. Blood cells


Correct Option: E
Explanation:

Blood cells, particularly red blood cells, lack mitochondria.

The cis, medial and trans regions are found in which one of the following cell organelles of eukaryotes?

  1. Lysosomes

  2. Peroxisomes

  3. Vacuole

  4. Endoplasmic reticulum

  5. Golgi complex


Correct Option: E
Explanation:

Golgi complex consists of a series of flattened membrane vesicles or sacs surrounded by spherical membrane vesicles. The three well-defined regions that are present in the stack of the flattened golgi sac include cis, medial and trans. Secretory proteins and membrane proteins from the rough endoplasmic reticulum first reach the cis region of the golgi complex, and then move to the medial region and ultimately to the trans region. While passing through all these regions, they undergo modifications by the specialised enzymes of the sacs.

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