DNA From the Beginning KEY

Original Document: DNA From the Beginning

Teacher Notes: This assignment can take a long time, and is a lot of reading, clicking through animations. I suggest breaking it into sections. Alternately, I've used the site in class on a projector and students filled out the answers in class as a group, with us discussing the sections. Some of the chapters are very detailed and I only skim over.

Chapter 1: Children Resemble Their Parents

a)  Distinguish between the pistil and the stamen of a plant. stamens are the male sex parts, pistils are female

b)  Do the problem set.   Explain why it was important for Mendel to control certain factors in his experiment. He needed to make sure that the plants were crossed only in the way he wanted so that he could observe their offspring

Chapter 2:  Genes Come in Pairs

a)  List all of the traits that Mendel examined in his experiment.

stem length, seed shape, seed coat color, seed color, flower position, pod shape, pod color

b) Go to Problem.   Describe the steps you would need to take to get a pure-bred colored flowered plant. self fertilize and see if all offspring are the same as the parent, if so then it is purebred

Chapter 3:  Genes Don’t Blend

a) After viewing the animation, go to Problem.   What is the best way to determine what trait is dominant? Cross two opposites together and see what the offspring look like, tall x short = tall

Chapter 4: Some Genes Are Dominant

a) Distinguish between a gene and an allele. each form of a gene is called an allele

b) What happens when two heterozygous (yellow-seeded) plants are crossed? 3/4 yellow, 1/4 green 

c)  Go to Problem:  What is the genotype of the F1 plants?     __Cc__

Chapter 5: Genetic Inheritance Follows Rules

a) View animation and go to Problem.  What types of gametes will a TtYy plant produce? _____TY, Ty, tY, ty______
b) How many of the offspring (from Problem) are tall, yellow? ___9___  short, green?  __1____

c) What is the Law of Independent Assortment?  ____the inheritance of one gene does not depend on the other gene______

Chapter 6: Genes Are Real Things

a) Why does wood float? __________cells filled with air__________________________________
b) How did Hooke define a cell?  ______________by the dark staining nucleus________________________

Chapter 7: All Cells Arise from Preexisting Cells

a) What are the phases of mitosis? ______interphase, prophase, metaphase, anaphase, telophase__________________

b) What holds sister chromatids together? _________centromere_________________
c) Describe the position of the chromatids during metaphase:  _______lined up_______
d) What does "omnis celula e cellula" mean? ________all cells arise from other cells __________

Chapter 8: Sex Cells Have One Set of Chromosomes, Body Cells Have Two

a) What organism did Theodor Bovari study? _________worms______________
b) During prophase 1 of meiosis, chromosomes form pairs called:_________homologs_______________
c) Meiosis I ends with _____telophase_____, there are ______2_____ daughter cells.
d) How many cells are there at the end of meiosis 2? _____4____

Chapter 9: Specialized Chromosomes Determine Gender

a) What are the two male chromosomes? ____XY________ Female? ______XX_______
b) How many chromosomes are found in female mealworms? ____20_____________
c) In humans, which parent determines the sex of the offspring? ____father (male)__________

Chapter 10:  Chromosomes Carry Genes

a) What did Thomas Morgan study?  _____fruit flies__________
b) What offspring resulted from the mutant white eyed male and the red eyed female? _____all red eyed___________
c) When these offspring were crossed, only the ___males______ had white eyes.

Chapter 11:  Genes Get Shuffled When Chromosomes Exchange Pieces

a) Summarize the idea of "linkage groups": _________genes are linked and inherited together_______________________
b) Linkage groups could be used to construct ____maps_______
c) What is "crossing-over"? __ chromosomes switch sections of genes____________________________

Chapter 12: Evolution Begins With the Inheritance of Gene Variations

a) What happens when plants self fertilize over many generations? ______they are smaller, not as healthy__________
b) Hybrids yield more corn, this phenomenon is called ________hybrid vigor___________.

Chapter 13: Mendelian Laws Apply to Human Beings

a) What is the name of the diagram used to track inheritance in humans? ____pedigree________
b) Which of Victoria’s nine children had hemophilia?  __Leopold_____ Was the child male or female?___male____
c) Which of her daughters were also carriers? _____Alice, Beatrice______________
d) What happened to the Romanov family in Russia? _were killed__________________

Chapter 14: Mendelian Genetics Cannot Fully Explain Human Health and Behavior

a) What is the ERO? ________________Eugenics Record Office_____________________
b) What is Farragut's famous quote? ____Damn the torpedos...__________________________________
c) Do you think love of the sea or fearlessness is something that we inherit in our genes? answers vary, good for discussions