Tag: bacteria - introduction, shape and structure

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Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Sex factor of bacteria is

  1. RNA

  2. Sex pili

  3. F-factor

  4. Chromosome replicon
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

F-factor is also called as fertility factor. It is the sex factor of bacteria. It allows the transfers of genes from one bacterium carrying the factor to another bacterium lacking the factor by the process of conjugation. It is found in some bacteria only.

Thus, the correct answer is 'F-factor.'

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Murein of bacterial cell wall is derivative of

  1. Vitamin

  2. Fat

  3. Organic acid

  4. Sugar
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The bacterial cell wall is made up of Peptidoglycan or murein. It is a polymer that is made up of sugars and amino acids. The sugar component is made up of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). NAM is then attached to an amino acid chain of L-alanine, D-glutamic acid, diaminopimelic acid (DAP) and D-alanine. 

Thus, the correct answer is 'Sugar.'

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Bacterial cell membrane is made up of

  1. Chitin

  2. Cellulose

  3. Proteins and phospholipids

  4. Fats
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Bacteria is a unicellular prokaryotic organism. It has a cell wall around the cell membrane. The bacterial cell membrane is made up of proteins and phospholipids. the proteins in are randomly distributed in the phospholipid bilayer of the cell membrane.

Thus, the correct answer is 'Proteins and phospholipids.'

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Teichoic acid is present in cell wall of

  1. Bacteriophage

  2. Mycoplasma

  3. Nostoc

  4. Pneumococcus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Teichoic acids are characteristic components of the cell wall of Gram-positive bacteria. Pneumococcus is a well-known Gram-positive bacterium, whereas the others listed do not possess this specific cell wall structure.

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Some bacteria have a capsule outside cell wall. It is made of

  1. Protein

  2. Cellulose

  3. Fat

  4. Mucopolysaccharide
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Some bacteria have a capsule outside cell wall. It is made up of mucopolysaccharide. The functions of mucopolysaccharide are;

  • It enhances the ability of bacteria to cause disease. 
  • It protects cells from engulfment by macrophages. 
  • It protects cells from desiccation.
Thus, the correct answer is 'Mucopolysaccharide.'

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Why is a capsule advantageous to a bacterium?

  1. It provides means of locomotion

  2. It allows bacteria to "hide" from host's immune system

  3. It allows the bacterium to attach to surface

  4. It protects the bacterium from desiccation.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • Bacterial capsule usually consists of a polysaccharide layer that lies outside the cell envelope. The capsule is found in both gram-positive and gram-negative bacterium.
  • The capsule is considered as virulence factor because it enhances the ability of bacteria to cause disease. It protects the bacterial cell from engulfment by macrophages.
  • Capsules also contain water which protects the bacterium from desiccation.
So, the correct answer is 'It protects the bacterium from desiccation'.

Multiple choice botany bacteria bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Ageing is slow or absent in

  1. Plants

  2. Parrot

  3. Monkeys

  4. Hydra
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The ageing is very slow or is not seen with the human eye in unicellular organisms but they do age. They undergo constant spontaneous DNA damage that can lead to the death of cells when it no longer able to reproduce. Plants and parrot are multicellular organisms with the higher level of complexity. The complexity is such that cell divisions are limited and when the cell is not able to divide, it ages with the decay of organelles and finally dies. So these organisms do age and die after a perticular period of time. but Hydra is the only species that does not age and lose its capability to reproduce. So we can say that ageing is slow or absent in hydra.

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Select the wrong statement of a bacterial cell

  1. Mesosome is formed by extensions of plasma membrane into cell

  2. Pili are elongated tubular structures made up of a protein

  3. Flagellum is composed of filament, hook and basal body

  4. Ribosomes are about 30 nm by 50 nm in size

  5. Fimbriae are small bristle like fibres sprouting out of cell.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Bacterial ribosomes are 70S, consisting of 30S and 50S subunits. The statement claiming they are 30 nm by 50 nm is incorrect as these numbers refer to the Svedberg units of the subunits, not the physical dimensions in nanometers.

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Which one of the following is absent in eukaryotes?

  1. Nucleolus

  2. Plastid

  3. Mesosome

  4. Ribosomes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Mesosomes are absent in eukaryotes.
  • Mesosomes refers to the folded invaginations in the plasma membrane of prokaryotes or bacterial cells.
  • Its main function is to increase the surface area of the plasma membrane. 
  • When the surface area of the membrane is increased it helps to carry out the cellular respiration more efficiently.
  • So, the correct answer is 'Mesosome'.