Question

1. What are the most common molecular structures found in the bacterial cytoplasm? Describe them, their roles and give examples of their function.
2. What are the major hypotheses for the origin of viruses? Describe these hypotheses in detail. What evidence exists that supports or does not support these hypotheses?

Answer 1

QUESTION- Molecular structure found in bacterial cytoplasm and their description and roles.

SOLUTION-

Structure found in cytoplasm-

A. Nucleoid

B. Plasmid

C. Raibosome

D. Inclusion

E. Mesosome

A. Nucleoid-

· It is the genetic material of bacteria that means it is bacterial chromosome.

· It is suspended in cytoplasm matrix, not surrounded by any envelop unlike eukaryotic cell.

· This genetic material does not contain any histone protein.

· In general, this genetic material is either double helix circular DNA or liner DNA.

· Function- It preserves and carries characteristics of organism. Its control all over cellular function.

B. Plasmid-

· Some of the bacteria contain extra chromosomal materials known as plasmid.

· It can replicate independently.

· Generally circular.

· Through conjugation it can be transfer.

· Function- It helps in antibiotic resistance, tolerance to toxin, produce toxin, helps in synthesis of enzyme.

      C. Ribosome-

· Bacteria has numerous raibosome suspended in cytoplasm.

· As eukaryotic cell it also contains 2-subunit 30s+50s = 70s.

· Function-It works as site of protein synthesis.

· It has tremendous evolutionary importance.

D. Inclusion-

· It is inorganic or organic deposits as reserve for unfavourable conditions.

· First time it observed in late 1800

· Example is Volutin, sulphur granules, lipid granules etc.

· Large inclusion is metachromatic granules found in Cornybacteria diptheriae.

E. Mesosome-

· It is a specialized structure formed by convolution of plasma membrane.

Function- It helps in respiration by increasing surface area of plasma membrane.

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