Name: ______Date: ______
8th Grade Science Mr.Vorstadt Heredity
Word Bank:
Genetic-make-up
Genetics
Different {2 X}
Same
TT or tt
Tt
Cross-pollination
Predict
Dominant
Alleles
Mitosis
Plants
Looks
Characteristics
Self-pollination
Chromosomes
Traits
Recessive
Capital-letter
Lower-case
Punnett-square
Genetics
A. Heredity—the passing of traits from parent to offspring.
1. Genes on chromosomes control the ______that show up in an organism.
2. The different forms of a trait that a gene may have are ______
3. During ______chromosomes separates and the ______
move into separate cells.
4. The study of how traits are inherited is ______.
5. The pollination within one plant is known as ______.
6. ______is taking pollen from one plant and
giving it to another plant.
B. Gregor Mendel—the father of genetics
1. Mendel was the first to use ______to explain heredity and to
trace one trait for ______.
2. Hybrid—receives ______genetic information for a trait from each parent.
a. ______allele—covers up or dominates the other trait
b. ______allele—the trait seems to disappear
3. Probability helps you ______the chance that something will happen.
4. A ______can help you predict what an offspring will look like.
a. ______stand for dominant alleles.
b. ______stand for recessive alleles.
5. Genotype—the ______of an organism.
a. homozygous—an organism with two alleles for one trait that are the ______
(written _____ or _____)
b. heterozygous—an organism with two alleles for one trait that are ______
(written _____)
6. Phenotype—the way an organism ______as a result of its genotype.
C. Punnett Squares
Directions: Fill in the Punnett Squares for the following and tell the genotypes and
phenotypes of the offspring:
Cross A (Tall is dominant)
Pure short female pea plant (tt) is crossed with a hybrid male pea plant (Tt).
Cross B (Rough seed is the dominant)
Pure smooth seed female (RR) crossed with pure rough seed male (rr)
Offspring’s Genotypes: ______
Offspring’s Phenotypes ______
Cross C: (The freckled trait is dominant)
Female hybrid (Ff) crosses with male hybrid (Ff)
Offspring’s Genotypes: ______
Offspring’s Phenotypes ______
Cross D: (White fur is a recessive trait)
Female with white fur (WW) crosses with male hybrid (Ww).
Offspring’s Genotypes: ______
Offspring’s Phenotypes ______
Meeting Individual Needs
Worksheet (continued)
Name ______Date ______
8th Grade Science Mr. Vorstadt
Directions: Fill in the P-Squares for the following and tell the genotypes and
phenotypes of the offspring:
Cross A (Tall is dominant)
Pure tall female pea plant is crossed with a hybrid male pea plant.
Genotypes: ______
Phenotypes: ______
Cross B (having dimples is a dominant trait)
Pure dimpled female crossed with pure non-dimpled male
Genotypes: ______
Phenotypes: ______
Cross C: (The widow’s peak is dominant)
Female hybrid crosses with male pure without a widow’s peak
Genotypes: ______
Phenotypes: ______
Cross D: (Tongue rolling is dominant)
Female Pure tongue roller crosses with a male hybrid
Genotypes: ______
Phenotypes: ______
Cross E: (Round pods are dominant)
Male Pure wrinkled pea plant with a hybrid female
Genotypes: ______
Phenotypes: ______
Name: ______Date:______
8th Grade Science Mr. Vorstadt
Heredity 2
Part A. Vocabulary Review
Directions: Complete the following sentences using the terms listed below.
alleles
dominant
genotype
heredity
heterozygous
homozygous
incomplete dominance 2-X
pedigree
phenotype
recessive
sex-linked
1. The allele for hemophilia is on the X chromosome and is a ______.
2. ______is the passing of traits from one generation to another.
3. The different forms a gene may have for a trait are called ______.
4. In ______both alleles are expressed in offspring.
5. A ______trait covers up other traits.
6. In a P-square, a small letter (t) stands for a ______allele.
7. The genetic makeup of an organism is called its ______.
8. ______is the way an organism looks and behaves a result of its gene type.
9. A ______show patterns of genetic inheritance in a family.
10. An organism with two alleles that are exactly the same is ______.
11. ______occurs when a group of gene pairs acts together
to produce a single trait.
12. An organism that has two different alleles for a trait is ______.
Chapternt
Directions: Study the meanings of the prefixes listed below. Then write a word
that contains a prefix from the list next to its definition.
hetero —different homo —same poly —many
13. ______an organism whose two genotype alleles are exactly the same
14. ______an organism with two different alleles for a trait
15. ______a type of inheritance where more than one set of genes
controls a trait
Directions: Complete the P-square by writing the parental genotypes in the
correct places and determining the possible genotypes of the offspring.
Directions: Fill in the P-Squares for the following and tell the genotypes and phenotypes of the offspring:
Cross A (Hybrid snapdragons are pink)
Female red snapdragon crosses with male hybrid
Offspring’s Genotypes: ______
Offspring’s Phenotypes ______
Cross B (Hybrid snapdragons are pink)
Female pink snapdragon crosses with male white snapdragon
Offspring’s Genotypes: ______
Offspring’s Phenotypes ______
Cross C: Hybrid snapdragons are pink)
Female hybrid crosses with male Hybrid
Offspring’s Genotypes: ______
Offspring’s Phenotypes ______
Cross D: (Hybrids snapdragons are pink)
Female red snapdragon crosses with male white snapdragon
Offspring’s Genotypes: ______
Offspring’s Phenotypes ______
Name: ______Date:______
8th Grade Science Mr. Vorstadt
Heredity 3
Part A.
Directions: human male (XY)and human female (XX)sex cells.
1. What do the letters X and Y stand for? ______
2. Which chromosome is found only in the male?______
3. Which person has two X chromosomes? ______
4. What percentage of the offspring is female? ______
Part B. Vocabulary Review
Directions: Complete the following sentences using the terms listed below.
X or Y
Extra
Beneficial
Mutation-recessive
Chromosome-mutation
Male
Carriers
Color-blindness
X-Linked
Female
Hemophilia
X
1. ______-genes that are altered or copied incorrectly.
2. A mutation can be harmful or ______
3. ______-caused by ______of chromosome 21.
4. Both parents have a ______allele responsible for the disorder and pass it to
their child.
5. Because the parents are ______, they don’t show the disease.
6. ______is a homozygous recessive disorder.
7. Genes that determine the sex of an organism are XX in ______
and XY in ______.
8. Females produce eggs with ______only. Males produce sperm with
______chromosome.
9. An allele inherited on an X chromosome is a ______.
10. ______is a sex-linked disorder caused by a recessive allele on the X
chromosome.
11. A ______follows a trait through generations of a family.
Meeting Individual Needs
One of the traits of pea plants that Mendel observed was seed shape. The seeds were either round or wrinkled. Mendel observed that round seed shape (R) dominated over the wrinkled shape (r).
Directions: Complete the P-square to show the possible offspring of two heterozygous
pea plants. Then answer the questions that follow.
1. What two forms of the trait for seed shape did Mendel observe? ______
2. What was the phenotype for seed shape of both parent plants? ______
3. What percentage of the possible types of offspring had the same genotype as the
parents? ______
4. What percentage of the possible types of offspring were homozygous? ______
5. What percentage of the possible types of offspring had the same phenotype as the
parents? ______