DNA from the Beginning Webquest Mendelian Genetics
Name: ________________________ Date: _______________ Per: _____
Go to http://www.dnaftb.org a ndc l i c kon“ Cl a s s i c a lGe ne t i c s ” .Y ouwi l lg ot hr oug ht hec onc e pt sont he right of the screen. To answer the questions below, you must read the CONCEPT and then click on ANIMATION at the bottom of the screen. Move through the animation by clicking the right arrow (). Whe ny our e a c ht hee ndoft hea ni ma t i on,y ous houl ds ee“ Ge ne ” ,t heg e ne .S heha sac omme nta nda question. Read these and answer the question. Move to the next concept by clicking on the links at the right of the screen.
Concept 1: Children Resemble their Parents 1) Wha ta r e“ f a c t or s ”a ndwha ti st hei rf unc t i on? 2) Explain how Mendel cross-fertilized his pea plants? 3) In your own words, what is the main idea expressed in concept 1? 4) Ge ne ’ sQue s t i on: Whya r en’ tt hei rna t ur a l l yoc c ur r i nghy br i da ni ma l s ,s uc ha sa leopard-camel cross?
Concept 2: Genes Come in Pairs 5) How was Mendel able to follow the inheritance of genes from parent to child? 6) What are the seven traits that Mendel observed? Describe the two phenotypes of each trait. a. b. c. d. e. f. g. 7) Mendel tells you that he purchased pure-bred seeds. How are pure-bred strains made? 8) What is each form of a gene called? What would be the genotype of a pure-bred yellow pea? 9) Ge ne ’ sQue s t i on:What is Mendel used a plant that could not be self-fertilized? How would this affect his observations?
Concept 3: Genes Do Not Blend 10) If you were to cross a tall pea plant with a short pea plant, would the offspring be of medium height? Why or why not? 11) With his experiments, how could Mendel support the idea that traits inherited from parents do not blend? 12) Ge ne ’ sQue s t i on:If pure-bred snap dragon plants with white flowers are crossed with pure-bred red flowers, the offspring have pink flowers. Since genes do not blend, what do you think happened?
Concept 4: Some Genes are Dominant 13) Explain why, after crossing a pure-bred green pea plant with a pure-bred yellow pea plant, all of the offspring are yellow. Show the cross. 14) When Mendel crossed the hybrid cross, some green peas reappeared. Why? 15) Cross 2 heterozygous yellow pea plants What percentage of offspring is green? What percentage of offspring is yellow? What is the ratio of the possible genotypes? 16) Ge ne ’ sQue s t i on:If the yellow pea color is dominant over the green pea color, then whyha v en’ ta l l peapl a nt sbec omey el l ows e eded? Concept 5: Genetic Inheritance Follows Rules 17) E x pl a i nMendel ’ s3: 1r a t i o.
18) E x pl a i nMendel ’ sL a wofS e g r eg a t i on.
19) Ge ne ’ sQue s t i on:The Manx breed of cats is known for being tailless, though some are born with tails. One dominant gene shortens the spine and is the cause for no tail. In a cross between two tailless Manx, you get (on average) a litter of kittens where for every 2 taill e s s , t her ei sonek i t t e nwi t hat a i l .Wha tha ppenedt oMe ndel ’ s3: 1r a t i o?( HI NT : s eet he“ di dy ouk now”c omme nt .I tma ya l s ohel pt odr a waPunnet ts qua r e. )