In this video, we're going to begin our lesson on enzymes. An enzyme is defined as a molecule that catalyzes or speeds up a chemical reaction, and it's able to speed up the chemical reaction without being consumed by the chemical reaction, which means that the enzyme is not going to be altered by the end of the reaction. Now, if we take a look at our image down below, notice that we're comparing a non-enzymatic reaction that has no enzyme to an enzymatic reaction that does have an enzyme. And so notice on the left over here, what we're showing you are some reactants, the starting material or the ingredients for a reaction being converted into the products over here on the right, but notice that no enzyme is involved. And typically, when there's absolutely no enzyme involved, then the reaction is going to occur really, really slow, too slow for life to be able to rely on reactions that do not have enzymes. And so, notice that over here on the right we're showing you the same reaction, and the same reaction over here we have, the substance being converted into the products. And this time, notice that an enzyme is present and the enzyme is represented by this structure that you see down below. And so the enzyme, its job, its function is to catalyze or speed up the chemical reaction so that it occurs much, much faster. And so you can see that the same reaction is able to occur at a much faster rate thanks to the enzyme, and so enzymes are all about catalyzing or speeding up chemical reactions. Now what's also important to note is that the term substrates is referring to the reactants of a chemical reaction that is catalyzed by an enzyme. And so if an enzyme is re involved, then the reactants are referred to specifically as substrates. So you can see that the substrates are pretty much the same exact thing as the reactants, and really the only difference is that substrates implies that an enzyme is involved, whereas reactants do not necessarily imply that an enzyme is involved. And so this here concludes our brief introduction to enzymes and how they act as catalysts to speed up chemical reactions, and substrates are the reactants of an enzymatic reaction. And so we'll be able to get some practice applying these concepts as we move forward in our course, and we'll also get to learn a lot more about enzymes 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
Enzymes - Online Tutor, Practice Problems & Exam Prep
Enzymes are biological catalysts that accelerate chemical reactions without being consumed. They convert substrates (reactants in enzymatic reactions) into products efficiently. Key functions include protein synthesis, DNA replication, and food digestion. Enzyme activity is influenced by environmental factors such as temperature, pH, and reactant concentration. Optimal conditions are crucial, as extreme temperatures or pH levels can lead to denaturation, reducing enzymatic activity. Understanding these concepts is essential for grasping biochemical processes in living organisms.
Enzymes
Video transcript
Functions of Enzymes
Video transcript
So now that we know that enzymes are catalysts and they speed up chemical reactions to make those reactions go faster, in this video, we're going to introduce some of the functions of enzymes. And so it turns out that enzymes actually have a wide variety of functions in living cells. We're not going to talk about all the different functions that enzymes can have, but some of those functions include the following three functions that we're showing you down below. The first is going to be building proteins. Enzymes are involved with building proteins and making sure that proteins are built at a fast rate. You can see here that the enzyme is this little choo choo looking train here, and this choo choo looking train here is an enzyme that's called a ribosome, which is specifically going to be used to build proteins using messenger RNA, and we'll be able to talk about this process of building proteins later in our course. But for now, what you can see here is that enzymes are involved with building proteins, and you can see this here represents the enzyme, and it's building this protein that you see here.
Now enzymes are also very important for copying DNA. You can see in this image that the DNA is being copied or duplicated so that there are two copies of the DNA, and this is something that enzymes are involved with and help to make sure that this process occurs at a fast enough rate. Last but not least, enzymes are also involved with the digestion of food. When we eat our foods, enzymes are involved with breaking down the foods that are in our stomachs. You can see over here, this represents a picture of our stomachs, and the food that is in our stomachs are going to be broken down using enzymes. Enzymes speed up the reactions that break down the foods we digest.
This here concludes our brief introduction to some of the functions that enzymes have, but the idea is that they speed up chemical reactions and are involved with a wide variety of functions in living cells. I'll be able to see you guys in our next video.
Which of the following are examples of the functions of enzymes?
a) A lactase enzyme breaking down lactose sugar in the small intestine.
b) A DNA polymerase enzyme synthesizing new strands of DNA.
c) A lipase enzyme breaking down fats (lipids) in the small intestine.
d) A helicase enzyme unraveling DNA so it can be replicated.
e) All of the above.
Environmental Factors Affecting Enzyme Activity
Video transcript
In this video, we're going to talk about some environmental factors that affect enzyme activity. Enzyme activity is defined as a measure of the amount of product that is produced by an enzyme in a certain amount of time. If an enzyme produces a lot of product within a given amount of time, then the enzyme has a lot of activity. But if the enzyme only produces a little bit of product within a given amount of time, then the enzyme only has a little bit of activity. Many environmental factors can actually affect an enzyme's activity. We're not going to talk about all of the factors that can affect an enzyme's activity, but three of those factors we are going to talk about below include the temperature, the pH of the solution, and the concentration of reactants.
Temperature can either be high, low, or in between. Another factor that could potentially affect enzyme activity is the pH of the solution, whether the pH is acidic, neutral, or basic. The third environmental factor we're going to discuss that affects enzyme activity is the concentration of reactants. Depending on the concentration of reactants, the enzyme will have either high or low activity.
It's also important to recall from our previous lesson videos that several environmental factors like high temperatures or even acidity can cause a protein to denature. In most cases, enzymes are proteins. Several environmental factors can also cause enzymes to denature. Recall that denatured proteins or enzymes lose their shape, and when they lose their shape, they lose their function. Denatured enzymes, because they lose their shape, therefore have decreased enzymatic activity.
Basically, the temperature needs to be just right for an enzyme to have optimal activity. If the temperature is too high or too low, the enzyme will not have optimal activity. The same goes for the pH. The pH cannot be too low or too acidic or too high or too basic; otherwise, that will affect the enzyme's activity. There needs to be a very specific pH for the enzyme to work optimally. The same goes for the concentration of reactants. If the concentration of reactants is too low, then the enzyme will not be able to produce a lot of products. If the concentration is too high, that could potentially oversaturate the enzyme, leading to improper functioning.
This concludes our introduction to how environmental factors can affect enzyme activity, and we'll be able to get some practice applying these concepts as we move forward in our course. I'll see you all in our next video.
Enzymes Example 1
Video transcript
So here we have an example problem that wants us to complete this sentence here using one of these four potential answer options down below. And it says certain species of bacteria are able to perform metabolic reactions involving enzymes in hot springs where the temperatures are really hot because of which one of these reasons. Now, the reason that bacteria are able to perform metabolic reactions in hot springs is because the enzymes that are involved are actually going to have optimal temperatures that are really, really high. So their enzymes have high optimal temperatures. And so these enzymes are going to work best in temperatures that are really really high. And so the correct answer here to this example problem is going to be option c. Now looking at some of the other options such as option b, it says, high temperatures make catalysis unnecessary, but really this is not true. Even in high temperatures, because the temperatures are high does not mean that catalysis is going to be unnecessary. So this is simply not true. And option d says that their enzymes are completely insensitive to temperatures, but this is also not going to be true. Enzymes are always going to be sensitive to their environments. And so these enzymes that have high optimal temperatures, if we were to remove these it work the same. So it's not that their enzymes are insensitive to temperature, it's just that their enzymes have high optimal temperatures. So option d here is not gonna be correct. And then option a says that they are able to maintain a lower internal temperature, but bacteria that are in hot springs are really going to have the same temperature as their outside environment. And so this is really not going to be the reason for why these enzymes are capable of working properly in hot springs. And so once again, the correct answer to this problem here is because their enzymes have high optimal temperatures. And so that concludes this example and I'll see you all in our next video.
Which characteristics are likely associated with an enzyme isolated from a human stomach where conditions are strongly acidic.
a) An enzyme that functions properly at 70 degrees Fahrenheit and at a neutral pH.
b) An enzyme that functions properly at 98 degrees Fahrenheit and at an acidic pH.
c) An enzyme that functions properly at 98 degrees Fahrenheit and at a neutral pH.
d) An enzyme that functions properly at 70 degrees Fahrenheit and at an acidic pH.
Do you want more practice?
Your Microbiology tutor
- Bacteria use the enzyme urease to obtain nitrogen in a form they can use from urea in the following reaction:&...
- Define and explain the importance of each of the following:a. catalaseb. hydrogen peroxidec. peroxidased. supe...
- An organism that has peroxidase and superoxide dismutase but lacks catalase is most likely ana. aerobe.b. aero...
- Suppose you inoculate three flasks of minimal salts broth with E. coli. Flask A containsglucose. Flask B conta...
- NAME IT Use the key in the Clinical Focus box to identify the gram-negative, oxidase-positive rod causing pneu...
- The _______________________ test detects if an organism can convert hydrogen peroxide to water and oxygen. The...
- Which of the following does not affect the function of enzymes?a. ubiquinoneb. substrate concentrationc. tempe...
- Which of the following statements best describes ribozymes?a. Ribozymes are proteins that aid in the productio...
- How does amination differ from transamination?
- Why are enzymes necessary for anabolic reactions to occur in living organisms?
- Why are vitamins essential metabolic factors for microbial metabolism?