Chapter 8, Problem 1RC

Summary Introduction

To determine: The structures and functions of bacteria, protists, fungi, viruses, and prions and their replication process along with energy requirements.

Introduction: Blood agar can be used to grow organisms like Streptococcus pneumonia as these bacteria use red blood cells, producing discoloration termed as alpha hydrolysis. The bacterial species Enterococcus faecalis does not use these red blood cells and therefore does not change the medium and can be used as a differential medium.

Explanation of Solution

The bacteria belong to the large class of prokaryotic micro-organisms. They are divided into various categories based on different parameters. These parameters can be shape, cell wall composition, mode of respiration, pathogenicity, and many more. Gram stain demarcates the bacteria into gram-positive and gram-negative bacteria. They can be pathogenic or non-pathogenic and live independently of the host organism. The genetic material of bacteria is DNA and has biomolecules for the replication, transcription, and translation.

Viruses are defined as infectious agents that can survive only by invading the living cells. They reproduce and produce multiple copies of them inside the cells. This causes cell lysis, and after harming the cells, they move to new cells. This cycle keeps on, and this is the reason that viruses are very harmful to living organisms. They are pathogenic, dependent on the host, and do not possess all the essential proteins and molecules for replication and energy derivation; therefore, they require a host for completing their life cycle.

Protists and fungi are eukaryotic heterotrophic organisms that also depend on organic food and are entirely dependent on other organisms for food and energy requirements.

The prions are the smallest infectious unit that does not contain any cellular structure and are only proteins that are capable of causing disease. These proteins can be misfolded proteins that result in the induction of a series of reactions in the brain capable of causing loss of brain function and death. The prions are infectious organisms that are dependent on the host for replication and energy requirements.