bio lab homework

If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

To log in and use all the features of Khan Academy, please enable JavaScript in your browser.

Biology library

Welcome to the biology library, unit 1: intro to biology, unit 2: chemistry of life, unit 3: water, acids, and bases, unit 4: properties of carbon, unit 5: macromolecules, unit 6: elements of life, unit 7: energy and enzymes, unit 8: structure of a cell, unit 9: more about cells, unit 10: membranes and transport, unit 11: more about membranes, unit 12: cellular respiration, unit 13: photosynthesis, unit 14: cell signaling, unit 15: cell division, unit 16: classical and molecular genetics, unit 17: dna as the genetic material, unit 18: central dogma (dna to rna to protein), unit 19: gene regulation, unit 20: biotechnology, unit 21: more molecular biology, unit 22: developmental biology, unit 23: bacteria and archaea, unit 24: viruses, unit 25: evolution and the tree of life, unit 26: more about evolution and natural selection, unit 27: history of life on earth, unit 28: ecology, unit 29: more about ecology, unit 30: biodiversity and conservation, unit 31: behavioral biology, unit 32: principles of physiology, unit 33: human biology, unit 34: plant biology, unit 35: ap free response worked examples, unit 36: crash course: biology and ecology, unit 37: meet the biology professional.

• school Campus Bookshelves
• menu_book Bookshelves
• perm_media Learning Objects
• login Login
• how_to_reg Request Instructor Account
• hub Instructor Commons
• Download Page (PDF)
• Download Full Book (PDF)
• Periodic Table
• Physics Constants
• Scientific Calculator
• Reference & Cite
• Tools expand_more
• Readability

selected template will load here

This action is not available.

Module 10: Human Inheritance

• Last updated
• Save as PDF
• Page ID 24577

Part 1: Human Traits Governed by Mendelian Genetics

Breaking news! These are all myths! Only ear wax is inherited in Mendelian ratios!

Small piece of PTC paper

• Two people who are heterozygous for tasting the chemical PTC marry. List the genotypes possible for their children regarding the tasting of PTC. Show your work.
• What is Alfred’s genotype?
• What is Alfreda’s genotype?
• What are Alfred’s possible sperm with regard to these two traits?
• What are Alfreda’s possible eggs with regard to these two traits?
• What is the probability that their first child will not roll its tongue and will have the normal number of fingers?

Part 2: Human Traits not Governed by Mendelian Genetics

There are many exceptions to Mendel’s Rules. For example, blood types in humans exhibit two exceptions: codominance and multiple alleles.

• Codominance: both alleles are expressed simultaneously (A and B alleles)
• Multiple Alleles: more than two alleles exist in a population (ABO)

Background Information:

Monoclonal antibodies are used to detect the blood surface markers governed by the ABO and Rh factor blood determinants. A sample of blood is combined with each specific antibody: anti-A, anti-B, anti-O or anti-Rh+ antibodies. A positive reaction, usually indicated by blood coagulation, indicates the presence of that particular blood surface marker. Antigens are molecules that trigger an immune response, causing the production of antibodies specific to that antigen.

• Synthetic blood
• Synthetic antibodies
• Blood typing tray
• Record your unknown blood type.
• Place one drop of the unknown blood into each of the three wells on the plastic plate.
• Apply one drop of anti-A antibody to one of the three wells and mix with a toothpick. If clumping occurs, the red blood cells have the A antigen embedded in their surface.
• Repeat the procedure using anti-B antibody in the second well.
• Finally, repeat the procedure for the third well using anti-Rh factor antibody.

What is your unknown blood type?

Is it Rh+ or Rh-?

Think About It

• Can two people with type A blood have a baby with type O blood? Explain your answer using a Punnett Square.
• A mother is Rh negative and her husband is Rh positive. If she becomes pregnant, what are the implications from an immunological standpoint for both fetus and mother, as well as subsequent fetuses?

Part 3: Human Genetics Problems

Genetic counselors are trained to detect inheritance patterns of genetic diseases based on information they obtain from the family. Imagine that you are a genetic counselor and you must solve the following cases based on the information provided. Use the following steps to solve each problem:

• Create a legend that indicates the gene pairs (alleles) involved. Use a capital letter to denote the dominant allele and lowercase letter to denote the recessive allele. Example: D= dimples d= no dimples
• Write the genotype and phenotype of the parents. Example: DD → dimples
• Use a Punnett Square to cross the potential gametes of the parents.
• Determine the probability based on the Punnett Square.
• Autosomal Recessive Inheritance (trait only expressed if homozygous recessive) An albino man (nn) marries a normally pigmented woman (N_) who has an albino mother. What is the chance that their children will be albino?
• Autosomal Dominant Inheritance (trait expressed as long as one dominant allele is present) A daughter wants to know what the chances are that she will develop Huntington’s disease, a degenerative disorder of the nervous system that appears during the ages of 30s to 40s. Her mother has Huntington’s while her father does not have the disease. Try to determine the possibilities from the information you have at hand. What further information do you need in order to more accurately determine the probability?
• X-Linked or Sex-Linked Recessive Inheritance (males more likely to express trait than females) Hemophilia is a blood disorder that is sex-linked. A woman carrier has children with a normal man. Determine the chances for girls and boys with hemophilia. [Remember that females have the XX genotype and males n have the XY genotype. Do not place an allele on the Y chromosome. Example: X N X n for female; XY for male]
• Multiple Alleles (more than two alleles in the gene pool of the population) In the population as a whole, there are three alleles (A, B, and O) determining blood type, although any one individual can have at most only two of the three alleles. A woman and her son are both blood type O. The woman claims that a man with blood type A is the father of the boy. Is this possible? Explain your answer.
• What fraction of human offspring receive an X chromosome from the mother?
• What fraction receive a Y chromosome from the father?
• Mr. and Mrs. Jackson have seven boys and one girl. What is the probability that their next child will be a girl?

Part 4: Pedigree Analysis

We will trace the inheritance pattern of the autosomal recessive trait albinism through four generations. The legend is as follows:

In the pedigree chart below determine the genotypes of each individual. Use a Punnett Square analysis to help you. Remember that the genotype of affected individuals is nn. If you cannot determine both gene pairs of a normal individual, indicate the genotype as N_. Put the genotype next to each symbol.

Part 5: Practice Problems

1. A certain disease is linked to the Y chromosome. What is the chance that a female could get this disease?

2. Polydactyly is an autosomal dominant condition. Assuming two non-polydactyl individuals make a baby, what is the chance of them having a polydactyl child?

3. If one of the parents described in question 2 is heterozygous for polydactyly, what is the chance of polydactyl offspring?

4. Two plants, which are heterozygous for a gene that describes plant height, are crossed. What percentage of their offspring will have the same phenotype as the parents if the trait is inherited via complete dominance? Incomplete dominance?

5. In dogs, wire hair (S) is dominant to smooth (s). In a cross of a homozygous wire-haired dog with a smooth-haired dog, what will be the phenotype of the F 1 generation? Genotypes?

6. A new disease was found to be sex-linked recessive. A man and a woman, wishing to have children together would like to know which percentage of their offspring could possibly have the disease. Neither parent has this disease. What is the highest possible percentage of their offspring that will have this disease? What proportion of their female offspring could get it? Males?

7. A boy, whose parents and grandparents have normal vision, is color-blind. Color-blindness is an X-linked recessive condition. What are the genotypes for his mother and his maternal grandparents?

8. Which of the following genotypes is not possible for the offspring of the following cross? AABb x aaBB

9. In a recent case in Spokane, Washington, a woman claimed a man was the father of her child. The man denied it. The man’s lawyer demanded that blood types be taken to prove the innocence of his client. The following results were obtained: Alleged father, Type O. Mother, Type A. Child, Type AB.

1. What are the possible genotypes for these three people?

2. Do you agree with the court’s decision? Why or why not?

10. It was suspected that two babies had been exchanged in a hospital. Mr. and Mrs. Jones received baby #1 and Mr. and Mrs. Simon received baby #2. Blood typing tests on the parents and the babies showed the following:

• Mr. Jones: Type A
• Mrs. Jones: Type O
• Baby #1: Type A
• Mr. Simon: Type AB
• Mrs. Simons: Type O
• Baby #2 Type O

Were the babies switched? Do you know this for sure?

Licenses and Attributions

CC licensed content, Original

• Biology Labs. Authored by: Wendy Riggs. Provided by: College of the Redwoods. Located at: http://www.redwoods.edu . License: CC BY: Attribution

Public domain content

• Derivative of ABO blood type. Authored by: InvictaHOG. Provided by: Wikimedia Commons. Located at: https://commons.wikimedia.org/wiki/File:ABO_blood_type.svg . License: Public Domain: No Known Copyright

• Military Families

The official provider of online tutoring and homework help to the Department of Defense.

Check Eligibility

Higher Education

Improve persistence and course completion with 24/7 student support online.

How it Works

Public Libraries

Engage your community with learning and career services for patrons of all ages.

Corporate Partners

Support your workforce and their families with a unique employee benefit.

Get Started

Tutor.com is now part of The Princeton Review !    Learn more

• Testimonials
• Become a Tutor
• Elementary Science
• Earth Science

Online Biology Tutors Available Now

Keeping up in biology class is hard enough without the worksheets, chapter questions, and lab reports your teacher assigns as homework. When you factor that stuff in, bio can seem completely overwhelming—even for high school students or first-year undergrads.

Fortunately, our online biology tutors are available for homework help the minute you need it.

They're online 24/7 to help you with biology homework questions, science projects, or test prep. Best of all, you can get a tutor anytime you're stuck on something—from home or on the go.

Biology help on demand

Every biology tutoring session happens in our online classroom, where you can chat with your tutor, share files, and draw on an interactive whiteboard. It doesn't matter if you need help after school, before school, or at three o'clock in the morning before your next biology test—we're here for you all day, every day.

Any biology problem, anytime

Our online tutors cover biology up to the introductory college level, including AP ® Biology , so they can help you with anything your bio teacher assigns. Here are just a few things you can get done faster and easier with help from an online biology tutor:

• Biology labs and lab reports
• Bio worksheets and problem sets
• Biology homework assignments
• Single problems or entire chapters
• Preparing for biology tests
• Reviewing tough concepts from class

Get started tonight

Get help with tonight’s homework— find a biology tutor now .

AP is registered trademark of the College Board, which was not involved in the production of, and does not endorse, this product.

• Our Company
• Homework Resources
• Social Studies
• SAT/Test Prep

Proudly Serving

• Colleges & Universities

For more information call us at:

800-411-1970