In this video, we're going to begin our introduction to bacteria. Now before we move on, it's important to emphasize that this video is just an introduction where we will briefly introduce some of the main features of bacteria. However, later in our course, we're going to talk a lot more details about the structures and functions and arrangements of bacteria. And so keep that in mind as we go through this video. Now first, it's important to note that the term bacteria is actually a plural term that's referring to many of the bacterial organisms. However, the singular form of the word is bacterium, which refers to only one single bacterial cell. Now bacteria are going to be organisms in one of the three domains of life, And so recall from our previous lesson videos that the three domains of life are bacteria, archaea, and eukarya. And so bacteria are one of the main domains of life. And it consists of unicellular organisms or organisms that are only made of 1 single cell. And they are also prokaryotic organisms because they lack a nucleus, they have no nucleus. And the bacteria are prokaryotic organisms along with the archaea, which recall are also prokaryotic. Now the bacteria, they can actually vary drastically in their shapes from being spherical in their shape to being rod shaped to even being spiral shaped. And again, we'll get to talk a lot more about the shapes and, the details of these bacteria later in our course. The bacteria can actually range in their length from being somewhere around 0.5 micrometers in length to being up to 10 micrometers in length, at their maximum. They're actually one of the most primitive groups of organisms. The bacteria are believed to be the very first domain to exist, domain of life to exist. So they have been around for 1000000000 of years longer than any other group of organism. The bacteria are major inhabitants of human bodies, and so they're actually found on the surface of our body, on our skins, but they're also found inside of our bodies lining our mucus membranes and things of that nature. And so we'll get to talk a lot more about the bacteria that inhabit our bodies, later in our course. But it's important to note here that these bacteria that inhabit our bodies form what is known as the human microbiota. And so later in our course, we'll get to talk a lot more details about the human microbiota, these bacteria that live on us and in us. Now bacteria, unlike the, eukaryotic organisms, they divide and multiply by a process known as binary fission. And, most of the bacteria are going to have a cell wall that is made of a molecule called peptidoglycan. And so later in our course, this will be one of the major focuses, when we talk about, gram positive and gram negative bacteria. But for now, this is just a brief introduction, and so note that many bacteria have cell walls made of a molecule called peptidoglycan. Now when we get to archaea a little bit later in our course, we'll see that archaea can also have cell walls. However, archaea do not have cell walls made of peptidoglycan. And so peptidoglycan is really a molecule that is unique to the bacterial domain. And again, we'll be able to focus on this detail a lot more later in our course. Now though many bacteria have been studied, it turns out that the vast majority of bacteria, most bacteria remain largely uncharacterized. And so there's still a lot more to know and learn about this domain bacteria. And so if we take a look at our image down below, at this introduction to bacteria, notice that, we're showing you a little snippet of our map of the microbial world from our previous lesson videos. And so notice that, we're focusing in on the prokaryotic groups, specifically the bacteria. And next, we'll be able to talk about the archaea, which, you can see that the the archaea is grayed out here intentionally to show you that that is going to be the next group that we'll talk about. Now over here on the right hand side, you'll see a collage of images showing you many different types of bacteria, such as bacillus anthracis, Vibrio cholerae, streptococcus pyogenes, micrococcus luteus, neisseria gonorrhea, and Escherichia coli. And so, what you'll note is that each of these different types of bacteria, different species and genuses of bacteria, they can have many different shapes and many different structures and features. And so, again, bacteria is a very, very large and diverse group. And, we'll be able to talk a lot more about their structures, their functions, and things of that nature as we move forward. But for now, this here is our, brief introduction to bacteria, and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.
- 1. Introduction to Microbiology3h 21m
- Introduction to Microbiology16m
- Introduction to Taxonomy26m
- Scientific Naming of Organisms9m
- Members of the Bacterial World10m
- Introduction to Bacteria9m
- Introduction to Archaea10m
- Introduction to Eukarya20m
- Acellular Infectious Agents: Viruses, Viroids & Prions19m
- Importance of Microorganisms20m
- Scientific Method27m
- Experimental DesignÂ30m
- 2. Disproving Spontaneous Generation1h 18m
- 3. Chemical Principles of Microbiology3h 38m
- 4. Water1h 28m
- 5. Molecules of Microbiology2h 23m
- 6. Cell Membrane & Transport3h 28m
- Cell Envelope & Biological Membranes12m
- Bacterial & Eukaryotic Cell Membranes8m
- Archaeal Cell Membranes18m
- Types of Membrane Proteins8m
- Concentration Gradients and Diffusion9m
- Introduction to Membrane Transport14m
- Passive vs. Active Transport13m
- Osmosis33m
- Simple and Facilitated Diffusion17m
- Active Transport30m
- ABC Transporters11m
- Group Translocation7m
- Types of Small Molecule Transport Review9m
- Endocytosis and Exocytosis15m
- 7. Prokaryotic Cell Structures & Functions5h 52m
- Prokaryotic & Eukaryotic Cells26m
- Binary Fission11m
- Generation Times16m
- Bacterial Cell Morphology & Arrangements35m
- Overview of Prokaryotic Cell Structure10m
- Introduction to Bacterial Cell Walls26m
- Gram-Positive Cell Walls11m
- Gram-Negative Cell Walls20m
- Gram-Positive vs. Gram-Negative Cell Walls11m
- The Glycocalyx: Capsules & Slime Layers12m
- Introduction to Biofilms6m
- Pili18m
- Fimbriae & Hami7m
- Introduction to Prokaryotic Flagella12m
- Prokaryotic Flagellar Structure18m
- Prokaryotic Flagellar Movement11m
- Proton Motive Force Drives Flagellar Motility5m
- Chemotaxis14m
- Review of Prokaryotic Surface Structures8m
- Prokaryotic Ribosomes16m
- Introduction to Bacterial Plasmids13m
- Cell Inclusions9m
- Endospores16m
- Sporulation5m
- Germination5m
- 8. Eukaryotic Cell Structures & Functions2h 18m
- 9. Microscopes2h 46m
- Introduction to Microscopes8m
- Magnification, Resolution, & Contrast10m
- Introduction to Light Microscopy5m
- Light Microscopy: Bright-Field Microscopes23m
- Light Microscopes that Increase Contrast16m
- Light Microscopes that Detect Fluorescence16m
- Electron Microscopes14m
- Reviewing the Different Types of Microscopes10m
- Introduction to Staining5m
- Simple Staining14m
- Differential Staining6m
- Other Types of Staining11m
- Reviewing the Types of Staining8m
- Gram Stain13m
- 10. Dynamics of Microbial Growth4h 36m
- Biofilms16m
- Growing a Pure Culture5m
- Microbial Growth Curves in a Closed System21m
- Temperature Requirements for Microbial Growth18m
- Oxygen Requirements for Microbial Growth22m
- pH Requirements for Microbial Growth8m
- Osmolarity Factors for Microbial Growth14m
- Reviewing the Environmental Factors of Microbial Growth12m
- Nutritional Factors of Microbial Growth30m
- Growth Factors4m
- Introduction to Cultivating Microbial Growth5m
- Types of Solid Culture Media4m
- Plating Methods16m
- Measuring Growth by Direct Cell Counts9m
- Measuring Growth by Plate Counts14m
- Measuring Growth by Membrane Filtration6m
- Measuring Growth by Biomass15m
- Introduction to the Types of Culture Media5m
- Chemically Defined Media3m
- Complex Media4m
- Selective Media5m
- Differential Media9m
- Reducing Media4m
- Enrichment Media7m
- Reviewing the Types of Culture Media8m
- 11. Controlling Microbial Growth4h 10m
- Introduction to Controlling Microbial Growth29m
- Selecting a Method to Control Microbial Growth44m
- Physical Methods to Control Microbial Growth49m
- Review of Physical Methods to Control Microbial Growth7m
- Chemical Methods to Control Microbial Growth16m
- Chemicals Used to Control Microbial Growth6m
- Liquid Chemicals: Alcohols, Aldehydes, & Biguanides15m
- Liquid Chemicals: Halogens12m
- Liquid Chemicals: Surface-Active Agents17m
- Other Types of Liquid Chemicals14m
- Chemical Gases: Ethylene Oxide, Ozone, & Formaldehyde13m
- Review of Chemicals Used to Control Microbial Growth11m
- Chemical Preservation of Perishable Products10m
- 12. Microbial Metabolism5h 16m
- Introduction to Energy15m
- Laws of Thermodynamics15m
- Chemical Reactions9m
- ATP20m
- Enzymes14m
- Enzyme Activation Energy9m
- Enzyme Binding Factors9m
- Enzyme Inhibition10m
- Introduction to Metabolism8m
- Negative & Positive Feedback7m
- Redox Reactions22m
- Introduction to Aerobic Cellular Respiration25m
- Types of Phosphorylation12m
- Glycolysis19m
- Entner-Doudoroff Pathway11m
- Pentose-Phosphate Pathway10m
- Pyruvate Oxidation8m
- Krebs Cycle16m
- Electron Transport Chain19m
- Chemiosmosis7m
- Review of Aerobic Cellular Respiration19m
- Fermentation & Anaerobic Respiration23m
- 13. Photosynthesis2h 31m
- 14. DNA Replication2h 25m
- 15. Central Dogma & Gene Regulation7h 14m
- Central Dogma7m
- Introduction to Transcription20m
- Steps of Transcription22m
- Transcription Termination in Prokaryotes7m
- Eukaryotic RNA Processing and Splicing20m
- Introduction to Types of RNA9m
- Genetic Code25m
- Introduction to Translation30m
- Steps of Translation23m
- Review of Transcription vs. Translation12m
- Prokaryotic Gene Expression21m
- Review of Prokaryotic vs. Eukaryotic Gene Expression13m
- Introduction to Regulation of Gene Expression13m
- Prokaryotic Gene Regulation via Operons27m
- The Lac Operon21m
- Glucose's Impact on Lac Operon25m
- The Trp Operon20m
- Review of the Lac Operon & Trp Operon11m
- Introduction to Eukaryotic Gene Regulation9m
- Eukaryotic Chromatin Modifications16m
- Eukaryotic Transcriptional Control22m
- Eukaryotic Post-Transcriptional Regulation28m
- Post-Translational Modification6m
- Eukaryotic Post-Translational Regulation13m
- 16. Microbial Genetics4h 44m
- Introduction to Microbial Genetics11m
- Introduction to Mutations20m
- Methods of Inducing Mutations15m
- Prototrophs vs. Auxotrophs13m
- Mutant Detection25m
- The Ames Test14m
- Introduction to DNA Repair5m
- DNA Repair Mechanisms37m
- Horizontal Gene Transfer18m
- Bacterial Transformation11m
- Transduction32m
- Introduction to Conjugation6m
- Conjugation: F Plasmids18m
- Conjugation: Hfr & F' Cells19m
- Genome Variability21m
- CRISPR CAS11m
- 17. Biotechnology3h 0m
- 18. Viruses, Viroids, & Prions4h 56m
- Introduction to Viruses20m
- Introduction to Bacteriophage Infections14m
- Bacteriophage: Lytic Phage Infections12m
- Bacteriophage: Lysogenic Phage Infections17m
- Bacteriophage: Filamentous Phage Infections8m
- Plaque Assays9m
- Introduction to Animal Virus Infections10m
- Animal Viruses: 1. Attachment to the Host Cell7m
- Animal Viruses: 2. Entry & Uncoating in the Host Cell19m
- Animal Viruses: 3. Synthesis & Replication22m
- Animal Viruses: DNA Virus Synthesis & Replication14m
- Animal Viruses: RNA Virus Synthesis & Replication22m
- Animal Viruses: Antigenic Drift vs. Antigenic Shift9m
- Animal Viruses: Reverse-Transcribing Virus Synthesis & Replication9m
- Animal Viruses: 4. Assembly Inside Host Cell8m
- Animal Viruses: 5. Release from Host Cell15m
- Acute vs. Persistent Viral Infections25m
- COVID-19 (SARS-CoV-2)14m
- Plant Viruses12m
- Viroids6m
- Prions13m
- 19. Innate Immunity7h 15m
- Introduction to Immunity8m
- Introduction to Innate Immunity17m
- Introduction to First-Line Defenses5m
- Physical Barriers in First-Line Defenses: Skin13m
- Physical Barriers in First-Line Defenses: Mucous Membrane9m
- First-Line Defenses: Chemical Barriers24m
- First-Line Defenses: Normal Microflora5m
- Introduction to Cells of the Immune System15m
- Cells of the Immune System: Granulocytes29m
- Cells of the Immune System: Agranulocytes25m
- Introduction to Cell Communication5m
- Cell Communication: Surface Receptors & Adhesion Molecules16m
- Cell Communication: Cytokines27m
- Pattern Recognition Receptors (PRRs)45m
- Introduction to the Complement System24m
- Activation Pathways of the Complement System23m
- Effects of the Complement System23m
- Review of the Complement System12m
- Phagoctytosis21m
- Introduction to Inflammation18m
- Steps of the Inflammatory Response26m
- Fever8m
- Interferon Response25m
- 20. Adaptive Immunity7h 14m
- Introduction to Adaptive Immunity32m
- Antigens12m
- Introduction to T Lymphocytes38m
- Major Histocompatibility Complex Molecules20m
- Activation of T Lymphocytes21m
- Functions of T Lymphocytes25m
- Review of Cytotoxic vs Helper T Cells13m
- Introduction to B Lymphocytes27m
- Antibodies14m
- Classes of Antibodies35m
- Outcomes of Antibody Binding to Antigen15m
- T Dependent & T Independent Antigens21m
- Clonal Selection20m
- Antibody Class Switching17m
- Affinity Maturation14m
- Primary and Secondary Response of Adaptive Immunity21m
- Immune Tolerance28m
- Regulatory T Cells10m
- Natural Killer Cells16m
- Review of Adaptive Immunity25m
- 21. Principles of Disease6h 57m
- Symbiotic Relationships12m
- The Human Microbiome46m
- Characteristics of Infectious Disease47m
- Stages of Infectious Disease Progression26m
- Koch's Postulates26m
- Molecular Koch's Postulates11m
- Bacterial Pathogenesis36m
- Introduction to Pathogenic Toxins6m
- Exotoxins Cause Damage to the Host40m
- Endotoxin Causes Damage to the Host13m
- Exotoxins vs. Endotoxin Review13m
- Immune Response Damage to the Host15m
- Introduction to Avoiding Host Defense Mechanisms8m
- 1) Hide Within Host Cells5m
- 2) Avoiding Phagocytosis31m
- 3) Surviving Inside Phagocytic Cells10m
- 4) Avoiding Complement System9m
- 5) Avoiding Antibodies25m
- Viruses Evade the Immune Response27m
Introduction to Bacteria - Online Tutor, Practice Problems & Exam Prep
Bacteria are unicellular, prokaryotic organisms that lack a nucleus and are one of the three domains of life, alongside archaea and eukarya. They exhibit diverse shapes, including spherical, rod, and spiral forms, and range in size from 0.5 to 10 micrometers. Bacteria reproduce through binary fission and typically possess a cell wall made of peptidoglycan, a unique feature distinguishing them from archaea. They play crucial roles in human microbiota, influencing health and disease. Despite extensive study, most bacteria remain uncharacterized, highlighting the need for further research in bacteriology.
Introduction to Bacteria
Video transcript
Which of the following is not a characteristic of bacteria?
Which of the following groups is the most diverse and abundant group of organisms on Earth?
Do you want more practice?
Here’s what students ask on this topic:
What are the main differences between bacteria and archaea?
Bacteria and archaea are both prokaryotic organisms, meaning they lack a nucleus. However, they have several key differences. Bacteria typically have cell walls made of peptidoglycan, whereas archaea do not. Instead, archaea have unique cell wall compositions that can include pseudopeptidoglycan. Additionally, the lipid composition of their cell membranes differs; bacteria have ester-linked lipids, while archaea have ether-linked lipids. Genetically, archaea share more similarities with eukaryotes in terms of their replication, transcription, and translation processes. Furthermore, archaea often thrive in extreme environments, such as high temperatures or high salinity, whereas bacteria are found in a wider range of habitats.
How do bacteria reproduce?
Bacteria reproduce primarily through a process called binary fission. In binary fission, a single bacterial cell, or bacterium, duplicates its genetic material and then divides into two identical daughter cells. The process begins with the replication of the bacterial chromosome. Once the chromosome is replicated, the cell elongates, and the two chromosomes are separated to opposite ends of the cell. A septum, or dividing wall, forms in the middle of the cell, eventually splitting the cell into two separate, genetically identical cells. This method of reproduction allows bacteria to multiply rapidly under favorable conditions.
What is the human microbiota and why is it important?
The human microbiota refers to the community of microorganisms, including bacteria, that inhabit various parts of the human body, such as the skin, mouth, gut, and other mucosal surfaces. These microorganisms play crucial roles in maintaining health by aiding in digestion, producing essential vitamins, and protecting against pathogenic microbes. The balance of the microbiota is important for immune system function and overall health. Disruptions to this balance, known as dysbiosis, can lead to various health issues, including infections, inflammatory diseases, and even metabolic disorders. Understanding the human microbiota is essential for developing new therapeutic strategies.
What are the different shapes of bacteria?
Bacteria exhibit a variety of shapes, which are often used to help identify and classify them. The three main shapes are: 1) Cocci: These are spherical or oval-shaped bacteria. Examples include Streptococcus and Staphylococcus. 2) Bacilli: These are rod-shaped bacteria. Examples include Escherichia coli and Bacillus anthracis. 3) Spirilla: These are spiral or corkscrew-shaped bacteria. Examples include Spirillum and Vibrio cholerae. Each shape can have variations, and some bacteria can change shape depending on environmental conditions. The shape of a bacterium can influence its mobility, how it interacts with its environment, and its ability to cause disease.
What is peptidoglycan and why is it important in bacteria?
Peptidoglycan is a complex polymer that forms a mesh-like layer outside the plasma membrane of most bacteria, providing structural support and shape. It is composed of sugars and amino acids, creating a strong, rigid structure. Peptidoglycan is crucial for maintaining the integrity of the bacterial cell wall, protecting against osmotic pressure and environmental stress. It is also a target for antibiotics, such as penicillin, which inhibit peptidoglycan synthesis, leading to cell lysis and death. The presence of peptidoglycan is a key feature distinguishing bacteria from archaea, which do not have peptidoglycan in their cell walls.
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