Classification of Living Organisms

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Questions and Answers

What is the primary purpose of classification in biology?

To divide organisms into groups based on shared features.

What is a taxon?

A taxon is a group of organisms in a classification system.

List the hierarchy of taxa in the correct order.

Kingdom, Phylum, Class, Order, Family, Genus, Species.

What characterizes a species according to biological classification?

A species is a group of organisms that can interbreed and produce fertile offspring. Signup and view all the answers

Who developed the Binomial Nomenclature system and when?

Carl Linnaeus developed the Binomial Nomenclature system in the 18th century. Signup and view all the answers

How are prokaryotes classified within the hierarchy of taxa?

Prokaryotes are classified as unicellular organisms. Signup and view all the answers

What distinguishes viruses from other kingdoms in classification?

Viruses are classified as non-cellular organisms. Signup and view all the answers

What are the three main groups of multicellular organisms in kingdom classification?

Plants, fungi, and animals. Signup and view all the answers

Which group of organisms is classified as protoctists?

Protoctists are unicellular organisms. Signup and view all the answers

What are the basic differences between the lytic and lysogenic cycles of viral reproduction?

The lytic cycle results in cell lysis and produces 100 to 200 progeny phages, while the lysogenic cycle integrates viral nucleic acid into the host genome without cell destruction, and no progeny are produced immediately. Signup and view all the answers

Describe the two main structural features that differentiate prokaryotic cells from eukaryotic cells.

Prokaryotic cells lack membrane-bound organelles and have nucleoid DNA, while eukaryotic cells contain organelles like mitochondria and have a defined nucleus. Signup and view all the answers

How do lymphocytes contribute to the body's immune response when a pathogen enters?

Lymphocytes produce antibodies that bind to antigens of the pathogen, activating the lymphocyte to clone itself and produce large quantities of the same antibody. Signup and view all the answers

What conditions favor the spread of the influenza virus and how can it be prevented?

Influenza spreads through respiratory droplets from an infected individual and can be prevented by practicing good hygiene, sufficient sleep, and managing stress. Signup and view all the answers

List three shapes of bacteria and provide an example of each.

Spherical (coccus), rod-shaped (bacilli), and spiral (spirilla) are three shapes of bacteria, with examples such as Streptococcus, Escherichia coli, and Treponema pallidum respectively. Signup and view all the answers

What is the role of peptidoglycan in bacterial cells?

Peptidoglycan provides structural support and strength to the bacterial cell wall, helping to maintain shape and protect against osmotic pressure. Signup and view all the answers

Define what an epidemic and a pandemic are, in the context of infectious diseases.

An epidemic is a widespread outbreak of an infectious disease affecting many people in a specific area, while a pandemic is an epidemic that crosses borders and affects a larger geographic region. Signup and view all the answers

Identify two types of viruses based on their host and give examples.

Plant viruses include the tobacco mosaic virus, while animal viruses include HIV and the influenza virus. Signup and view all the answers

What are the two main ways bacteria can reproduce, and how do they differ?

Bacteria primarily reproduce asexually through binary fission, creating clones, but can also reproduce by sporulation or budding, which involves different mechanisms. Signup and view all the answers

Explain the significance of the term 'prophage' in the lysogenic cycle.

A prophage refers to the integrated viral nucleic acid within the host genome during the lysogenic cycle, which can later lead to the activation of the lytic cycle. Signup and view all the answers

Study Notes

Classification of Living Organisms

Classification is the arrangement of organisms into groups based on shared characteristics, including genetic similarities, evolutionary history (phylogeny), and more.
Taxa are groups within a hierarchical system, with broader groups (Kingdom) encompassing narrower ones (Species).
Taxonomy is the study of classification.
The hierarchy of taxa includes Kingdom, Phylum, Class, Order, Family, Genus, and Species.
Species are groups of organisms that can interbreed and produce fertile offspring, sharing similar characteristics.
Binomial nomenclature, developed by Carl Linnaeus, is used to name species.

Kingdom Classification

Viruses are non-cellular biological structures needing a host cell for reproduction. They have nucleic acid (DNA or RNA), contained within a protein capsid, possibly enveloped in a membrane.
Prokaryotes are unicellular organisms (e.g., bacteria, cyanobacteria, archaea).
Protists include diverse unicellular or simple multicellular organisms.
Fungi are multicellular organisms.
Plants are multicellular, photosynthesizing organisms.
Animals are multicellular organisms.

Prokaryotic Cells

Prokaryotes, including bacteria, lack membrane-bound organelles and a true nucleus. Their DNA is in a nucleoid region.
Cell walls of bacteria contain peptidoglycan.
Bacteria can have various shapes: spherical (cocci), rod-shaped (bacilli), comma-shaped (vibrio), spiral-shaped (spirilla/spirochaetes).

Viral Structure and Classification

Viral shapes vary (spherical, rod-like, bacteriophages).
Viruses are categorized by their nucleic acid (RNA or DNA) type.
Examples of viruses include plant viruses like Tobacco Mosaic Virus and animal viruses like HIV and influenza. Bacteriophages infect bacteria.
Epidemics and pandemics involve widespread infectious disease outbreaks affecting large populations at various geographic scales.

Influenza Virus

Influenza is a single-stranded, enveloped RNA virus.
Spread via droplets from infected individuals.
Prevention includes hygiene, rest, nutrition, and stress management.

Viral Diseases

Viral diseases include COVID-19, influenza, HIV/AIDS, chickenpox, and others.

Viral Reproduction

The lytic cycle is a common viral reproductive pathway.
The lysogenic cycle, found in bacteriophages, involves virus DNA integrating into the host cell's genome.

Bacterial Reproduction and Types

Bacteria reproduce asexually by binary fission.
Bacteria are diverse in their habitats and roles.
Autotrophic bacteria obtain energy from sunlight (photoautotrophs) or inorganic chemical reactions (chemoautotrophs), including sulfur, iron, and nitrogen bacteria.
Heterotrophic bacteria derive energy from other organisms.
Nitrogen-fixing bacteria are an example of symbiotic bacteria.
Pathogenic bacteria cause diseases (tuberculosis, pneumonia, cholera, etc.).

Archaea

Archaea are prokaryotes found in various environments, especially extreme ones (high salt, high temperature).

Immune response

The immune system responds to pathogens with antibodies produced by lymphocytes
Antigens on pathogens bind to antibodies, activating lymphocytes, which then divide rapidly creating a clone to produce more antibodies.

Human Immunodeficiency Virus (HIV)

HIV causes AIDS, transmitted through bodily fluids (blood, semen, breast milk).
Prokaryotic organisms, like archaea, often inhabit extreme environments.

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Description

Explore the fascinating world of taxonomy and how organisms are classified based on shared characteristics and evolutionary history. This quiz covers the hierarchy of taxa, including Kingdom, Species, and the concept of binomial nomenclature developed by Carl Linnaeus.