Back To Course
Biology 101: Intro to Biology22 chapters | 151 lessons | 12 flashcard sets
Video: Mutagens: How the Environment Affects Mutation Rates
What causes mutations to occur in living things? How do we avoid mutations? Are mutations always bad? Discover answers to these questions and more in this lesson on mutagens.Mutagens: How the Environment Affects Mutation Rates
You must create an account to continue watching
Register for a free trial
Are you a student or a teacher?
Start Your Free Trial To Continue Watching
As a member, you'll also get unlimited access to over 75,000 lessons in math, English, science, history, and more. Plus, get practice tests, quizzes, and personalized coaching to help you succeed.
Free 5-day trialIt only takes a few minutes to set up and you can cancel at any time.
Already registered? Login here for access
Back
Your next lesson will play in
10 seconds
Lesson Transcript
Instructor:
April Koch
April teaches high school science and holds a master's degree in education.
What causes mutations to occur in living things? How do we avoid mutations? Are mutations always bad? Discover answers to these questions and more in this lesson on mutagens.
Introduction to Mutagens
Have you ever wondered how mutations arise in living things? You've probably heard stories about mutated beings emerging from toxic waste sites or secret laboratories. While these urban legends usually turn mutations into fantasy, it is true that mutations often come from external factors.
The environment we live in has a real impact on whether we experience genetic mutations. The quality of water we drink and the air we breathe can actually affect the integrity of our DNA. Our bodies are designed to correct any mistakes, but dangers from the environment can increase our chances of ending up with a mutation. An environmental agent that causes a mutation is called a mutagen.
Mutation Formation
 |
Remember that all mutations are changes in the nucleotide sequence of DNA. While chromosome mutations involve large portions of DNA, point mutations are smaller and typically affect one or two bases. Point mutations include base substitutions and insertions and deletions. While base substitutions only switch one base for another, insertions and deletions change the length of a DNA code. But, it's rarely the original DNA strand that undergoes a mutation. Most of the time, mutations occur while a new DNA molecule is being formed through DNA replication.
Recall the work of the enzyme DNA polymerase. During replication, this enzyme's job is to build the daughter DNA strand along the parent strand. Every once in a while, DNA polymerase makes a mistake in matching the right nucleotide to the parent strand. It puts the wrong nucleotide down and produces a daughter strand that is slightly incorrect. Normally, this only happens in about one in a billion nucleotides. But, there are certain things that can make it more likely that DNA polymerase will make a mistake. One of these is radiation from ultraviolet, or UV, rays. When UV radiation hits the cells in your body, it can change the way DNA polymerase works and increase the probability of a replication error. Ultraviolet radiation is an example of a mutagen.
Mutagens
Things that cause mutations are not always found outdoors. Mutagens are any chemical or physical agents that cause a mutation in an organism's DNA. We said before that mutagens come from the environment. But remember, the 'environment' for an organism is nothing more than the chemical and physical factors surrounding it. A bacterium's environment might only be the inside of your intestine. A lab mouse's environment might only be its cage, its food, and its water. Mutagens can be found in any part of the environment. The word 'mutagen' comes from the word part 'gen,' which is found in lots of scientific terms. 'Gen' means the 'origin' or 'creation' of something. Just like an allergen is anything that causes an allergy, a mutagen is anything that causes a mutation.
 |
UV radiation is just one of many mutagens that exist in our environment. Other mutagens include X-rays, extreme heat, or chemicals that react with DNA molecules. These agents can change the way molecules bond and react with one another, which increases the likelihood that a mistake will be made in the nucleotide sequence. An error in the DNA can cause problems for that cell. Skin cells are especially vulnerable to UV radiation because, obviously, they have the most direct exposure to the UV light that comes from the sun. This is why we try to protect our skin from the sun's potentially harmful rays. Though a point mutation may seem insignificant at the molecular level, we know that a single insertion, deletion, or base substitution can drastically harm an organism.
Mutations and DNA Polymerase
Fortunately for us, DNA polymerase always double-checks its work to make sure all the nucleotides have been replicated correctly. When it finds an error in the DNA sequence, it quickly stops and fixes it before replication. That way, the mistake won't get bigger with every new generation of DNA. But nobody's perfect, and some mistakes do get through. It's all about probability. The best thing we can do to avoid mutations is to decrease our exposure to mutagens that are found in our environment.
Mutations in the Real World
As we've seen in previous lessons, mutations can cause a variety of disorders. Human diseases caused by point mutations include cystic fibrosis, color blindness, Tay-Sachs disease, sickle-cell anemia, and cancer. We usually think of point mutations as being harmful to living things. They often make organisms more vulnerable, less healthy, or otherwise less likely to survive and reproduce in their respective environments.
 |
On the other hand, there are plenty of cases of advantageous mutations. Don't get the false impression that all mutations are 'bad.' Sometimes accidents are a good thing. In fact, mutations can take credit for many of the adaptations we see in organisms today. In any population, there are individuals that turn out significantly different from the rest. Mutations arise randomly in all species of organisms. If a mutation doesn't cause significant harm, then it may be passed down through successive generations. Over time, the mutation may become more and more common, until it becomes the 'new normal.' In fact, this is one way that species branch out and evolve into new varieties of organisms. In the long run, all of us are the result of some kind of mutation. So, we can thank mutations for the diversity we see in plants and animals today.
Keep in mind, however, that simple mutations can't give an organism some amazing new structure or power. A person couldn't instantly sprout wings or fins because he got a mutation. All those legends about mutant monsters and lab-created superheroes are just fantasy. If you really want to gain super-human powers, you're better off just hitting the gym.
Lesson Summary
Point mutations are small changes in the DNA sequence that occur through mistakes during DNA replication. DNA polymerase normally matches the daughter nucleotides to the parent strand and corrects any mistakes through a proofreading step. Mutations are more likely to form when an organism is exposed to a mutagen. Mutagens are chemical or physical agents that cause mutations. While mutations often cause harmful disorders, they also increase the genetic diversity of populations. Advantageous mutations are passed on through generations and are ultimately responsible for the variety of living things.
Learning Outcome
You will be able to define mutagens and explain how they occur by the conclusion of this lesson.
To unlock this lesson you must be a Study.com Member.
Create your account
Register for a free trial
Are you a student or a teacher?
Unlock Your Education
See for yourself why 30 million people use Study.com
Become a Study.com member and start learning now.
Become a MemberAlready a member? Log In
BackEarning College Credit
Did you know… We have over 160 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.
To learn more, visit our Earning Credit Page
Transferring credit to the school of your choice
Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.
You are viewing lesson
Lesson
3 in chapter 10 of the course:
- What is a Point Mutation? - Definition, Causes & Types 6:15
- Effects of Mutations on Protein Function: Missense, Nonsense, and Silent Mutations 8:31
- Mutagens: How the Environment Affects Mutation Rates 6:00
-
7:44
Next Lesson
Effects of Frameshift Mutations: Definitions and Examples
- Point Mutations in DNA: Types, Diseases & Examples 4:37
- Go to Types & Effects of Genetic Mutations
Mutagens: How the Environment Affects Mutation Rates Related Study Materials
- GRE Information Guide
- Computer Science 310: Current Trends in Computer Science & IT
- Earth Science 105: Introduction to Oceanography
- Computer Science 331: Cybersecurity Risk Analysis Management
- Computer Science 336: Network Forensics
- World Literature: Drama Since the 20th Century
- Visual Art Since the 18th Century
- World Literature: Drama Through the 19th Century
- Defamation, Libel & Slander
- Elements of Music Overview
- ILTS Prep Product Comparison
- CTEL Prep Product Comparison
- TASC Prep Product Comparison
- FSA Prep Product Comparison
- SHSAT Prep Product Comparison
- MEGA Test Accomodations
- Study.com Grant for Teachers
Latest Courses
- Materials & Resources for an Early Childhood Classroom
- Obstructive Shock: Causes, Symptoms & Treatment
- Interpreting & Calculating Seasonal Indices
- Managing Classroom Behaviors of Young Children
- Taekwondo Lesson Plan
- Normalization & Invisibility of Privilege in the Workplace
- Practical Application: Reducing Job Stress Using Time Management
- Solving Equations Using the Least Common Multiple
- Quiz & Worksheet - Real-World Applications of Learning
- Quiz & Worksheet - Dante's Inferno 4th Level of Hell
- Quiz & Worksheet - Coaching Agreements
- Quiz & Worksheet - Third-Person Pronouns
- Quiz & Worksheet - Code of Ethics for Teaching
- Flashcards - Measurement & Experimental Design
- Flashcards - Stars & Celestial Bodies
Latest Lessons
- GACE Program Admission Assessment Test II Mathematics (201): Practice & Study Guide
- NY Regents Exam - Earth Science: Tutoring Solution
- FTCE Physics 6-12 (032): Test Practice & Study Guide
- Human Growth and Development: Homework Help Resource
- Life Span Developmental Psychology: Tutoring Solution
- Chapter 11: A World in Flames (1931 - 1941)
- CLEP Social Sciences and History: The Hellenistic Age and Macedonia
- Quiz & Worksheet - SOP Purpose, Content & Form
- Quiz & Worksheet - Definition & Function of IGD
- Quiz & Worksheet - Factors to Consider in Planning a Pregnancy
- Quiz & Worksheet - Mistakes of Composing Definitions in Technical Writing
- Quiz & Worksheet - Sequence in Technical Documents
Popular Courses
- Solving Equations on the CLEP Scientific Calculator
- Eugenics: Definition & Explanation
- Homeschooling in Hawaii
- Critical Thinking Skills for Kids
- Illinois Common Core Social Studies Standards
- New Careers for Teachers
- Homeschooling in North Dakota
- Brain Breaks for Kids in the Classroom
- 5th Grade Science Standards in California
- Arkansas Science Standards for First Grade
- Illinois Science Standards for 5th Grade
- Industrial Revolution Lesson Plan
Popular Lessons
Math
Social Sciences
Science
Business
Humanities
Education
History
Art and Design
Tech and Engineering
- Tech and Engineering - Videos
- Tech and Engineering - Quizzes
- Tech and Engineering - Questions & Answers
Health and Medicine
Explore our library of over 75,000 lessons
Browse by subject
