Biology: Endospores and Sporulation

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Questions and Answers

What is the primary function of dipicolinic acid in endospore formation?

To synthesize the peptidoglycan cortex

To initiate the process of endosporulation

To trigger the formation of the spore coat

To stabilize the proteins and DNA in the endospore (correct)

What is the process by which a single endospore forms within a bacterium?

Endosporulation (correct)

Binary fission

Sporulation

Vegetative cell division

What is the purpose of the cortex in the endospore?

To protect the endospore from UV light and harsh chemicals (correct)

To regulate the water content of the endospore

To facilitate the germination of the endospore

To provide structural support to the endospore

What is the outermost layer of the endospore?

Exosporium Signup and view all the answers

What is the final stage of endospore formation?

Dehydration and maturation Signup and view all the answers

What is the result of the plasma membrane pinching off during endosporulation?

Creation of a double membrane around the DNA Signup and view all the answers

What is the primary function of ribosomes in all organisms?

Protein synthesis Signup and view all the answers

What is the main characteristic of endospores?

Resistance to adverse conditions Signup and view all the answers

What is the composition of the 50S ribosomal subunit?

23S and 5S rRNA Signup and view all the answers

What is the purpose of plasmids in genetic engineering?

To insert specific genes Signup and view all the answers

What is the function of inclusion granules in bacteria?

Reserve deposits Signup and view all the answers

What is the difference between prokaryotic and eukaryotic ribosomes?

Size and composition Signup and view all the answers

During protein synthesis, where does the mRNA attach to?

30S subunit Signup and view all the answers

What is the use of Bacillus stearothermophilus spores?

Quality control of heat sterilization equipment Signup and view all the answers

What is the composition of the cytoplasm in a prokaryotic cell?

80% water, and a mix of various compounds including nucleic acids and enzymes Signup and view all the answers

What is the primary function of the cytoplasm in a prokaryotic cell?

To facilitate most bacterial metabolism leading to growth and replication Signup and view all the answers

What is the function of mesosomes in a prokaryotic cell?

To increase plasma membrane surface area and enzymatic content Signup and view all the answers

What is the characteristic of the nucleoid in a prokaryotic cell?

It has a single circular chromosome of double-stranded DNA Signup and view all the answers

What is the function of plasmids in a prokaryotic cell?

To confer protective traits such as antibiotic resistance Signup and view all the answers

What is the characteristic of conjugative plasmids?

They allow the exchange of DNA between bacterial cells Signup and view all the answers

What is the advantage of plasmids that code for proteins that degrade antibiotics?

It makes the bacteria more resistant to antibiotics Signup and view all the answers

What is the size range of plasmids?

5-100 genes Signup and view all the answers

Study Notes

Prokaryotic Cell Structure

Cytoplasm:
- Composition: 80% water, nucleic acids (DNA and RNA), enzymes, amino acids, carbohydrates, lipids, inorganic ions, and low molecular weight compounds
- Function: site of most bacterial metabolism leading to growth and replication
Mesosomes:
- Definition: Plasma membrane infoldings
- Functions:
  - Role in cell wall formation
  - Involved in DNA replication in prokaryotes
  - Increase plasma membrane surface area and enzymatic content
  - Aid in transfer of chromosomes to daughter cells
  - Analogous to cristae in mitochondrial eukaryotic cells
Nucleoid:
- Definition: Region with a single circular chromosome of double-stranded, supercoiled DNA
- Characteristics: No nuclear membrane, nucleoli, mitotic spindle, or histones

Plasmids

Definition: Small, nonessential, extra-chromosomal DNA molecules
Characteristics:
- Circular (linear in a few species)
- Present in cytoplasm, can be incorporated into chromosomal DNA
- Often confer protective traits, such as antibiotic resistance or toxin production
- Can be passed on through conjugation
- Replicate independently
Functions:
- Confer antibiotic resistance
- Encode proteins for virulence factors
- Allow for horizontal gene transfer
- Useful in genetic engineering/rDNA technology

Ribosomes

Definition: Site of protein synthesis in all organisms
Characteristics:
- Most abundant in cytoplasm (up to 15,000)
- 70S ribosomes (50S and 30S subunits) in prokaryotes, 80S in eukaryotes
- Chemically composed of ribosomal RNA (rRNA) and protein
Function: Workbench for protein synthesis, translating mRNA into proteins

Inclusion Granules

Definition: Nonliving, membrane-less reserve deposits
Examples:
- Volutin granules (inorganic phosphate)
- Polysaccharide granules (glycogen or starch)
- Lipid inclusions (e.g., PHB granules)
- Sulfur and nitrogen granules
- Gas vacuoles (buoyancy and flotation in aquatic bacteria)

Endospores

Definition: Dormant, resistant structures produced intracellularly upon starvation
Characteristics:
- Resistant to adverse conditions (high temperatures, irradiation, cold, organic solvents)
- Contains calcium dipicolinate
- Not a mechanism of reproduction
Formation:
- Endosporulation process
- DNA replication, membrane wall formation, and calcium dipicolinate incorporation
- Peptidoglycan cortex, spore coat, and core wall formation
- Dehydration and maturation before release from mother cell