GeneticsBig IdeaGenes have the code for many traits and are passed from parents to their offspring.Essential Questions
Bill Nye GenesIt's in your genes! ... I think. What does that really mean? Watch Bill Nye "Genes" to find out. While you watch, pay close attention to what genes and chromosomes are. Take notes on your worksheet in your notebook. When you are done watching the video, answer the questions on the back of the worksheet.Human Traits Lab - Background (Characteristics and Traits)BackgroundWe are beginning a lab about human traits to begin our genetics unit. Before scientists begin an experiment, they do some research to learn about what they will be studying, so we will begin by learning what characteristics and traits are. Start by reading the definitions in our book (p.176) or our Interactive Reader (p.84). After finding the book definitions, paraphrase them in your notebook and write examples of each. (Be sure to put your own examples, not the examples from the book!) Use the dictionary, thesaurus, and paraphrasing reference page as well as good reading skills to help you paraphrase the definitions.PurposeObserve some of the diversity in our class. (How diverse is our class?)DataFirst, collect data from your own group. Remember to measure height and arm span using centimeters NOT feet and inches. Most of the world uses meters, centimeters, and kilometers to measure (America is weird that way), so it's important that you practice using these units. When you are done collecting group data, we will total up our data for the whole class.AnalysisUse the class totals to make a bar graph of our data. We will use the graph to analyze our data and describe the diversity we see. Also answer analysis questions 1-4.ConclusionDescribe the diversity you observed in our class for the characteristics we studied. In which areas do we have the most diversity? the least diversity? Explain your answer. For example, in one class, all the students had brown eyes. This was the tallest bar, but it didn't represent the most diversity because all the students were the same. Instead, eye color is the characteristic where they had the least diversity (most similarity). In the same class, we had five different arm span categories ranging from 131 cm to 180 cm. We had a lot of diversity in that trait. Graph your data to see where your class has the most and least diversity. Take a look at the sample graph to make sure you understand.DNA — The Double Helix Game
- How are genes related to traits?
- How are genes passed from parents to their offspring?
When you finish reading and playing this game, you should know the basic shape and parts of DNA molecules as well as how it copies itself.
DNA is an amazing molecule because it can make copies of itself! Other molecules can't do this: protein molecules can't copy themselves; neither can sugar, water, or oxygen molecules. DNA can, though! And that makes life possible. That is how traits are passed from parents to offspring: the parent's DNA makes a copy of itself to give to the offspring.
Learn how DNA does this by playing a game called "DNA, The Double Helix" on the Nobel Prize website. First, copy these notes into your notebook, and tape in the worksheet. You should finish all the notes except the organisms chart BEFORE you copy the DNA molecules.Visit the Nobel Prize website and play the double helix game. Be sure to read the introduction and the details as you play the game. If you don't, you will miss key information. As you work, record and compare the number of chromosomes and the number of genes in various organisms.Use your completed notes and worksheet to answer the questions on the QuizStar called "DNA, The Double Helix."Onion Skin Slide LabGoal:Examine onion skin cells under the microscope and identify the nucleii (plural of nucleus).DNA has the code for an organism's traits, and it is found inside the nucleus of each cell. Can you find this very important organelle under the microscope? Follow the BBC Bitesize directions for creating an onion skin slide. Record your lab report in your science notebook. If you need help remembering how to write a lab report, be sure to use the reference we taped into our science notebooks. Here are some special instructions:Purpose: Write "Observe the nucleus of onion skin cells."Hypothesis: (Since we're not really answering a question, leave this section out.)Materials: Make a list of the materials you need based on the directions on the BBC Bitesize website.Procedure: Write "See BBC Bitesize Onion Skin Slide instructions."Data: After getting the slide in focus on low power, get it into focus on high power. If you see gray/black shapes, you probably have bubbles on your slide. Ignore those. The onion skin cells will most likely be irregular rectangles with a yellow-brown outline. Find the darker yellow-brown shape inside each cell. That is the nucleus. Draw 2-3 onion skin cells in detail. Label the cell wall/membrane and nucleus. Desribe any other details you notice. If you didn't get to finish drawing your own slide, here are some photos of other slides:Conclusion: Since we are not answering a question with this lab, summarize what you learned here. Recall what is inside the nucleus. Why is it such an important organelle? What does it look like?DNA ComediansDNA is the secret chemical code that cells use to make proteins. Can you decode it? First you need to learn some key terms and a little about how proteins are made; Then use what you learn to decode the punch lines on your DNA Comedians worksheet.The genetic material in cells is DNA. A single piece of DNA is a chromosome. Some bacteria have a single, circular chromosome, while many organisms have multiple chromosomes shaped like long strands. Humans, for example, have 46 chromosomes. Each chromosome can have many, many genes on it. A gene is the part of a chromosome that has the code for a single protein. Genes are like DNA sentences. Just like in English, these sentences are made of words. These DNA "words" are called codons. Unlike English words, which might be 1 letter, 2 letters, or 15 letters long, codons are always 3 letters long, The letters are chemicals called DNA bases. You remember those from the DNA game we played (A, C, T, G).
DNA Code NameYou're going under cover, and you're going to need a code name, a DNA code name. What's that, you say? I'll tell you: Pretend your name is a protein. Each letter is an amino acid in the protein chain. You are going to make a DNA chain that codes for your name. Then, you get to choose which pictures or symbols represent each nucleotide. Put it all together in a beautiful picture on a plain white piece of paper or construction paper. (No lined paper!)
- Use the information in the paragraph above to define the words at the top of your worksheet.
- Follow the worksheet directions to decode the punch lines!
The Story of You ... and MitosisOnce upon a time, you were born ... If you missed the story of you in class, click here to read it. Be sure to read with a New Jersey accent.After you read the story, watch the BrainPOP video about Mitosis. When you're done do the review quiz. How did you do? What do you still need to learn?The Cell Cycle GameYour cells copy themselves, including their DNA. That's how DNA gets passed on from parents to offspring. That's also why each of your cells has a copy of the same 46 chromosomes. Mitosis is the part of the cell cycle where the DNA duplicates itself, but there is a little more to know about the cell cycle. The cell cycle is controlled by two chemicals CDK and cyclin.Today, you are learning on the job because you are working for CDK & Cyclin Partners, and you will be in charge of helping cells divide. Here is what to do:
- Write your name. (First name is required, last name is extra credit.)
Sample J A M E S (As in James Bond)
- Write the codon for each "amino acid" (letter in your name) Use stop codons for spaces. You can find the codons on your codon reference page from the DNA Comedians worksheet.
Sample J=ATC A=GCT M=ATG E=GAG S=TCA Sooo...
- Use a symbol to represent each base in the codons.
Sample: G=* C=& A=% T=@ Soooo....
ATC=%@& and GCT=*&@ Soooo...
We're going to write about the process of mitosis, and it's important to know when different events happen in that process. To do a good job writing about a process, we usually want to write about the events in order, and we want to include language in our writing that gives details about when each part happened. Let's get started!(Use the Cell Cycle worksheet to help you do the following.)
- Go to the BrainPOP game, Controlling the Cell Cycle.
- Read the introduction and fill in the blanks in your notes (front and back).
- Use your notes to help you on the job! Your goal is to copy the cell accurately. Since mistakes can lead to problems, your cell will self-destruct if you don't copy it correctly!
Fingerprint LabWe inherit a lot of traits, but not all of them. Some traits are determined by our environment or our habits. Many traits are influenced by a mix of genes, environment, and habits. What about your fingerprints? Are these inherited? Does your DNA create those tiny patterns; is it something in your environment; or is it random? We're going to do a lab to find out!Over the holiday, ask your family to let you fingerprint them for our lab. I will not be collecting these sheets. We will only use them as data. If someone in your family does not want to be fingerprinted, ask him/her if you may look at the patterns of their fingerprints and write that down. If they are not comfortable with that, then don't collect their fingerprints. If you're having a big holiday get-together, see how many family members will do the lab with you. This will give us great data to work with! When we come back from break, we will do the rest of the lab.After you collect fingerprints, analyze their shape. Are they arches, whorls, or loops? To learn what the different patterns look like, view the images on the State of California Fingerprint Imaging System website. There are also more detailed directions on this FBI reference sheet.Reproduction Reading
- Cell Cycle Flow Map
First, read about the cell cycle on page 153 in your Holt Life Science textbook. The three stages of the cell cycle are mitosis, interphase, and cytokinesis. After reading, make a simple flow map naming the three stages in order.
- Cell Cycle Sentences
Also examine and read Figure 4 on pages 154 and 155 in your book. Use what you learn to put the following sentence in the correct order. Write them in your notebook, but indent about an inch. We're going to add an introductory phrase later.
The cell goes through mitosis.
The cell must copy its chromosomes, which happens during interphase.
Two daughter cells form. Their DNA is identical.
The cell begins cytokinesis.
The cell also grows.
The chromosomes separate into two identical sets.
- Introductory Phrases
Once you have your sentences in the correct order, let's add introductory phrases to them to give more detail about the process of mitosis. Although there are many different introductory phrases that we could use, let's practice using "Before ________," "During _________," and "After ___________,". don't forget the commas!
Before mitosis, the cell must copy its chromosomes, which happens during interphase.
- Mitosis Chart
-Draw each stage of mitosis. On your drawing, label any of the following that are visible: cell membrane, nuclear membrane, chromosomes, centrioles, and spindle fibers.
-Under each drawing, describe what happens to the chromosomes and nuclear membrane as well as any other significant changes.
There are two basic types of reproduction: sexual and asexual. In science, sexual reproduction doesn't have to mean anything like what you are thinking. It just means there are two parents that give DNA to the offspring. For example. A honeysuckle plant just outside our classroom might reproduce with a plant on the other side of the school even though they can't ever get close to each other. The pollen from one plant is carried by the wind or insects to another plant and a seed forms. Since the seed got DNA from two parents, it was sexual reproduction, even thought the parents never even met.
To understand asexual reproduction, you need to know that the prefix "a-" means not. Something that is even on both sides is symmetrical. Something that is uneven is asymmetrical. A theist believes in the existence of a god. An atheist does not. Asexual reproduction is simply not sexual. It does not require two parents to contribute DNA.
As you read about reproduction, complete the 3-level reading guide and Venn Diagram.Genetics book reading: See pages 268-273 in this pdf if you have to read at home. If you didn't get in in class, you may print the 3-level reading guide and p. 274 from the reading.Did you get it? Check yourself by trying this Sexual vs. Asexual Reproduction Dragster.Virtual Flower DissectionWe often use plants to do genetic experiments because they grow fairly quickly and we can control which plants are the parents. How do we do control which plants become the parents? In this virtual flower dissection, you will begin learning the parts of a flower. Plants that make flowers use them to reproduce. They are the reproductive organs of the plant. Eventually, the flower becomes seeds and fruit. The seeds, of course, are the plant's offspring. The fruit entices animals to spread the plants seeds.Clone a Mouse!We're going to clone a mouse. We're going to use 3 mice to help us, though. Which mouse will the baby look like? If you know the rules of genetics, you'll be able to figure it out. Go to the University of Utah Gentics website, and read about the process. Before you actually clone your mouse, answer the questions on the worksheet and make your hypothesis.Lick Your RatsI know you've been waiting for it all year; you finally get to lick some rats! OK, so maybe it wasn't on the top of your bucket list, but it's good, really, and while you're doing it, you're going to learn. Do you remember that each cell in your body has the same 46 chromosomes? So then why do your skin cells have such different traits from your nerve cells or your muscle cells? It's because they only use part of their DNA. A skin cell uses certain genes on the chromosomes and a muscle cell uses different ones. The genes that a cell doesn't use are sort of turned off, but how does that happen? How are some genes turned on and others turned off? This is a new field of study called epigenetics.In this activity you will be a mother rat and you will lick your pups to groom them and show them affection. (Yes it's virtual. No, you don't get to lick any real rats, as much as you may have wanted to. Sorry.) Here's what to do:
Coin Tossing ModelIn our plant experiment and in our endangered critter experiment, one allele was stronger than the other one, so if a critter inherited one blue-tail allele and one orange-tail allele, the stronger blue allele won, and the critter had a blue tail. Our plants followed the same pattern. If they inherited a yellow-seedling allele and a green-seedling allele, they were green. The green-seedling trait was stronger than the yellow-seedling trait. These stronger traits are called dominant. The weaker trait that gets hidden by the dominant trait is the recessive trait.In our critters experiment, we used colored dots to represent alleles, but normally, we use letters. Capital letters represent dominant alleles and lowercase letters represent recessive alleles. In our model we will use P to represent a purple-flower allele, and p to represent the recessive white-flower allele. There are three different possible genotypes:
- Go to the University of Utah Learn Genetics "Lick Your Rats" page.
- Read the introduction and watch the video of the rat mom with her pups.
- Do the Lick a Rat Pup! activity. Listen to the introduction; then click on your baby mouse to groom it. Try grooming it a little and notice what happens to its GR Gene; then try grooming it a lot and see what happens to the gene.
- Click on the button next to "Investigate high and low-nurtured rat pups." Read and listed to all 4 sections. Pay close attention to the animations.
- Create a Venn diagram comparing high- and low-nurtured rat pups.
The prefix homo- means same. A homozygous organism has two of the same allele for a trait (either two dominants or two recessives). In contrast, the prefix hetero- means different, so heterozygous organisms have two different alleles for a trait (one dominant and one recessive).Use theCoin-Tossing Model worksheet as a guide to help you testing Mendel's hypothesis one more time. Record your data in the data table. If you were absent, copy the notes from someone who was here and have them explain how to do the experiment. You will need a penny and can flip it for both parents yourself. Remember to speak Biology! Say your vocabulary words aloud as you work and write.When your group is done, have one partner submit your data through the Google form so we can add up everyone's results. Use the class data to analyze our results:
- PP - Homozygous dominant
- Pp - Heterozygous
- pp - Homozygous recessive
Furry FamilyIf you cross a homozygous white-flowered plant with a heterozygous purple-flowered plant, what will the offspring look like? Can any of them be homozygous dominant? Geneticists use a tool called a punnet square to help them Figure out problems like this. Today some bunnies from a Furry Family are going to help you learn how to use punnet squares. Furry Family worksheets are available in class with questions you must answer and helpful gene references at the top.
- Calculate the total for each category (column) using this formula [=SUM(___:___)] blank 1-1st # in the column blank 2 - bottom # in the column
- Calculate the percent for each genotype based on the totals.
- Calculate the percent for each phenotype based on the totals.
- Calculate the ratio of purple- to white-flowered plants.
- Make pie charts showing Mendel's percents/ratios and our results.
- Do the tutorial and answer questions 1 through 5c on the handout. (To re-start the tutorial at any time, refresh your screen and the activity will start again.)
- Play the game. (If you feel confused at all, ask for help and/or re-do the tutorial.)
- Answer questions 6-8.