The following is the base sequence on one strand of a DNA molecule.

A A T G C C A G T G G T T C G C A C

1. What is the base sequence of the complementary DNA strand?

2. What is the base sequence of the mRNA read from the original DNA

strand?

3. What protein will the messenger RNA code for?

4. Transcription takes place in the___________________________ (part of cell).

Translation occurs in the ______________________________ of cells on the

surface of organelles called _________________________.

5. Match the word or phrase on the left with the description on the right.

_____chromosome A. segment of DNA that helps to control

_____diploid a particular hereditary trail such as

_____egg eye-color

_____gamete B. cell that contains two sets of

_____gene chromosomes

_____haploid C. the male sex cell

_____homologous chromosomes D. a sex cell

_____n E. threadlike structures inside the

_____2n nucleus

_____sperm F. the diploid number of chromosomes

for a species

G. cell that contains one set of

chromosomes

H. members of each chromosome pair

I. the basic number of chromosomes for

a species

J. the female sex cell

BACKGROUND: A long time ago, in a galaxy far, far away, a great race of beings lived on a planet called ZORK. The inhabitants were known as Zorkonians. They are made up of 10 basic genes (unit) that code for their appearance. Each one of these genes is made up 2 alleles (traits). With this in mind, there are 1,024 different possible combinations for their appearance! This is called their phenotype or their physical appearance. If we look at their genes, there are 59,049 different combinations of the alleles! This is called the genotype or genetic makeup. Remember that we use letters for the alleles that control the genes and one letter or allele is inherited from each parent. You will be using Zorks, who use the same genetic principles as a pea plant, to see how genes are passed on and inherited. You will be using Punnett Squares to do this.

Here are some things to help you. You must understand these concepts and terms! I will use traits from the table on the next page as examples.

Phenotype: The physical appearance or what the gene makes an organism look like. Examples would be two eyes, yellow hair, and green lips from a zork.

1. Dominant: The trait that is shown the most. Example: Green hair is dominant over yellow hair.

2. Recessive: The trait that is hidden. In this example: yellow hair.

Genotype: The genetic makeup of an organism. We use letters for the genotype. Remember that you need to look at the genotype to see what the phenotype will be.

Example: There is a Gene or unit for hair color in a zork. The alleles or traits (individual genes) for hair color would be yellow and green. There are 2 alleles for each gene and we use letters for each allele. The capital letters are the dominant alleles and the lower case letters are the recessive alleles.

Gene Allele

Hair color 1. Green color = G

2. Yellow color = g

1. Heterozygous: The term used for different alleles. There is always one dominant and one recessive allele. Example: Gg. There is only one possibility for this!

2. Homozygous: The term used for having the same alleles. This will be either 2 dominant alleles or 2 recessive alleles. Example: GG or gg. There are 2 possibilities for this!

Please refer back to this to help you as you work through this assignment. You will use the table on the next page to complete the problems that follow. Everything you need is in the table! The following are the traits of a Zork, which we will use to study genetics. You will be studying one family. Be sure to read each problem carefully, because in each case the information is built upon the previous problem.

Allele	Trait	Dominant/Recessive	Genotype	Phenotype	Heterozygous	Homozygous
T	Tall	Dominant	TT,Tt	Tall	Tt	TT
t	Short	Recessive	tt	Short		tt
G	Green hair	Dominant	GG,Gg	Green Hair	Gg	GG
g	Yellow hair	Recessive	gg	Yellow Hair		gg
E	One Eye	Dominant	EE,Ee	One Eye	Ee	EE
e	Three Eyes	Recessive	ee	Three Eyes		ee
F	One Fang	Dominant	FF,Ft	One Fang	Ff	FF
f	Two Fangs	Recessive	ff	Two Fangs		ff
H	Two Horns	Dominant	HH,Hh	Two Horns	Hh	HH
h	One Horn	Recessive	hh	One Horn		hh
L	Purple Lips	Dominant	LL,Ll	Purple Lips	Ll	LL
l	Green Lips	Recessive	ll	Green Lips		ll
W	Two Wings	Dominant	WW,Ww	Two Wings	Ww	WW
w	No Wings	Recessive	ww	No Wings		ww
N	One Leg	Dominant	NN,Nn	One Leg	Nn	NN
n	Two Legs	Recessive	nn	Two Legs		nn
R	Green Skin	Dominant	RR,Rr	Green Skin	Rr	RR
r	Yellow Skin	Recessive	rr	Yellow Skin		rr
B	Thick Eyebrow	Dominant	BB,Bb	Thick Eyebrow	Bb	BB
b	Thin Eyebrow	Recessive	bb	Thin Eyebrow		bb

1. Cross a heterozygous green skinned zork with a yellow skinned zork.

A. What do the possible offspring look

Like?

2. Cross a homozygous two horned zork with a heterozygous two horned zork.

A. What are the genotypes of the possible offspring?

3. Cross a heterozygous green haired zork with a heterozygous green haired zork.

A. What are the genotypes and phenotypes of the possible offspring?

4. Cross a green lipped zork with a heterozygous purple lipped zork.

A. What are the number of phenotypes and genotypes of the offspring? Hint: Count what is in the boxes!

5. Tork, who is homozygous for tall meets Vorkina, who is short.

A. What are the phenotypes and genotypes if they were to have offspring?

6. Tork and Vorkina have two children. One is a boy named Torky and the other is a girl named Vorki. Many years later, Torky meets and marries a girl named Morkalina who is short.

A. What are the possibilities for the height of their offspring?

Hint: Look at 5A for information on Torky.

7. Vorki the daughter meets a zork named Spork, who is heterozygous for tall.

A. How many will be tall? How many will be short? How many will be TT?

How many will be Tt? How many will be tt?

8. Torky has green hair and Morkalina has yellow hair. They have four children and all of them have green hair. What phenotype and genotype must Torky be?

9. Spork and Vorki both have three eyes.

A. What would their offspring look like?

10. Using problems 5-9, give the phenotypes and genotypes of Tork, Vorkina, Torky, Morkalina, Spork and Vorki based ONLY on the traits given in the problems.

Zork Activities Created by: Rodger Moore rodger@rougien.reno.nv.us

Wooster High School, Reno, Nevada

Crossword Puzzle for Basic Principles of Genetics

Across

2. Mendel's principle of genetic inheritance stating that, for any particular trait, the pair of genes of each parent separate and only one gene from each parent passes on to an offspring.
5. Mendel's principle of genetic inheritance stating that different pairs of genes are passed to offspring independently so that new combinations of genes, present in neither parent, are possible.
9. An alternate form of the same gene.
11. The genetic makeup of an individual for a trait or for all of his/her inherited traits—not the observable or detectable characteristics.
12. An inheritance pattern in which a gene will have a different effect depending on the gender of the parent from whom it is inherited.
13. Genes whose effect does not normally occur unless certain environmental factors are present.
16. The observable or detectable characteristics of an individual organism; the detectable expression of a genotype.
17. Genes that are inherited by both men and women but are normally only expressed in the phenotype of one of them.
18. The inheritance pattern in which a single allele is responsible for a variety of traits.
21. The term for a genotype in which there are two recessive alleles.
22. Genes that can alter how certain other genes are expressed in the phenotype.
23. Genes that can either initiate or block the expression of other genes.
24. The general term for an allele that is masked in the phenotype by the presence of another allele.

Down

1. The general term for an allele that masks the presence of another allele in the phenotype.

3. A unit of inheritance usually occurring at a specific location on a chromosome.
4. Twins that come from the same fertilized egg
6. A trait that is determined by the combined effect of more than one gene.
7. An inheritance pattern in which a gene has more than two alleles.
8. The inheritance pattern in which two different alleles for a trait are expressed unblended in the phenotype of heterozygous individuals.
10. He acquired his understanding of genetics mostly through pea plant breeding experiments.
14. A genotype consisting of two different alleles of a gene for a particular trait.
15. A genotype consisting of two identical alleles of a gene for a particular trait.
19. A theory that inherited traits blend from generation to generation. Most of the leading scientists in the 19th century accepted it. However, Gregor Mendel proved that it was not correct.
20. The study of gene structure and action and the patterns of inheritance of traits from parent to offspring.

Define the following terms.

1. a. heredity_______________________________________________________________

b. genetics ______________________________________________________________

2. c. allele _________________________________________________________________

d. phenotype ____________________________________________________________

e. genotype______________________________________________________________

Complete the following sentences.

3. Mendel’s Law of ______________________________ shows that only the

dominant trait appears in the offspring of a cross between two pure

lines for different traits.

4. A trait that is hidden in the F₁generation but reappears in the F₂

generation is a ____________________________ trait.

5. Mendel’s Law of _____________________________________ states that during

reproduction the two factors that control each trait separate, and one

factor from each pair is passed to the offspring.

6. An organism is said to be _______________________________ when both

alleles on homologous chromosomes have the same expression.

7. If the two homologous chromosomes have different alleles for a trait,

the organism is ________________________________ for the trait.

8. The Law of ________________________________________ states that the

inheritance of alleles for one trait is not affected by the inheritance of

alleles for a different trait if the genes for the trait are located on

separate chromosomes.

9. Fill in the Punnett squares to show the possible offspring in the F₁and

F₂generations of a cross between pure line pea plants that produce

round seeds (RR) and pea plants that produce wrinkled seeds (rr).

10. Fill in the Punnett squares to show the F₁and F₂generations of

possible offspring of pure line pea plants that are tall (T) and produce

yellow seeds (Y) and pea plants that are short (t) and produce green

seeds (y).

Allele

Trait

Dominant/Recessive

Genotype

Phenotype

Heterozygous

Homozygous