Q2. What would be the expected ratio of genotypes in a cross between two parents who were both heterozygous?

Q3. Reproductive cells that only contain one copy of each gene are called ____.

Q4. If one parent has two genes for brown eyes (BB) and the other has two genes for blue eyes (bb), what is the chance that their offspring will have blue eyes?

Q5. What is located in the nucleus of your cells and contains all of your genetic information?

Copying DNA Sequence

The polymerase chain reaction (PCR) copies a sequence of DNA. To do this, a strand of DNA is mixed with nucleotides (DNA precursors). Nucleotides target a specific piece of DNA, as well as polymerase, an enzyme that helps to assemble DNA. Heat is applied until the temperature reaches 200 degrees F. The energy from the heating separates the DNA strands. The mixture is then cooled to 140 degrees F. At this temperature, the primers attach themselves to the DNA strands. Raising the temperature to 160 degrees F causes the nucleotides to begin to attach to the DNA strands. After all this, two copies of the DNA are created.

Q6. To separate the DNA strands during the polymerase chain reaction, the addition of _____________________ is necessary.

Paternity TestingDNA has become part of everyone’s vocabulary, and several crime shows on television use it as a key plot element. DNA has put criminals in jail and freed others. It is used as proof in trials and is an important dramatic tool on many television dramas and talk shows.Another use for DNA is not as dramatic. Because a child inherits the DNA of his or her parents, DNA testing can prove paternity. This is an example of a practical use for a scientific discovery.

Q7. Because every person’s DNA is unique (except for identical twins), what forensic tool can DNA testing replace?

Heredity, Then and Now

How often have you seen a young child and said, “She takes after her parents”? Many traits in a child do come from her parents. Physical and other characteristics, such as hair color and nose shape, are transmitted from one generation to the next. These characteristics, passed from one generation to the next, exist because of genetic code.

The first scientist to experiment with heredity was Gregor Mendel during the 19th century. Mendel experimented with pea plants and noted that characteristics appearing in “child” plants were similar to the “parent” plants. Mendel hypothesized that these characteristics were carried from generation to generation by “factors.”

It took many years of research to understand why children often look like their parents, but genetic code is now the basis of the study of heredity.

Q8. According to the passage, _________ is a primary determinant for characteristics of the next generation.

Heredity, Then and Now

How often have you seen a young child and said, “She takes after her parents”? Many traits in a child do come from her parents. Physical and other characteristics, such as hair color and nose shape, are transmitted from one generation to the next. These characteristics, passed from one generation to the next, exist because of genetic code.

The first scientist to experiment with heredity was Gregor Mendel during the 19th century. Mendel experimented with pea plants and noted that characteristics appearing in “child” plants were similar to the “parent” plants. Mendel hypothesized that these characteristics were carried from generation to generation by “factors.”

It took many years of research to understand why children often look like their parents, but genetic code is now the basis of the study of heredity.

Q9. The factors that Mendel hypothesized carried traits from one generation to the next is

Heredity, Then and Now

How often have you seen a young child and said, “She takes after her parents”? Many traits in a child do come from her parents. Physical and other characteristics, such as hair color and nose shape, are transmitted from one generation to the next. These characteristics, passed from one generation to the next, exist because of genetic code.

The first scientist to experiment with heredity was Gregor Mendel during the 19th century. Mendel experimented with pea plants and noted that characteristics appearing in “child” plants were similar to the “parent” plants. Mendel hypothesized that these characteristics were carried from generation to generation by “factors.”

It took many years of research to understand why children often look like their parents, but genetic code is now the basis of the study of heredity.

Q10. If you want to grow monster-sized pumpkins, from what kind of pumpkins do you want to get seeds to increase the probability of growing larger-than-average pumpkins?

A gardener is interested in growing pea plants of a particular height. He draws a Punnett square to display all the possible combinations of alleles when two hybrid pea plants are crossed to help him determine the possible genotypes of the offspring. T represents the dominant allele for tall plants, and t represents the recessive allele for short plants. The genotype of one parent plant is shown on the top of the square, and the other parent’s genotype is shown on the left of the square. The genotypes of the offspring are shown in the boxes. The Punnett square is shown here:

Q11. What is the probability that an offspring will be tall?

A gardener is interested in growing pea plants of a particular height. He draws a Punnett square to display all the possible combinations of alleles when two hybrid pea plants are crossed to help him determine the possible genotypes of the offspring. T represents the dominant allele for tall plants, and t represents the recessive allele for short plants. The genotype of one parent plant is shown on the top of the square, and the other parent’s genotype is shown on the left of the square. The genotypes of the offspring are shown in the boxes. The Punnett square is shown here:

Q12. Fill in the blanks to correctly complete the sentence:

The genotype of both parent plants is __________, which means that both parents will be __________.

Q13. What does it mean for a gene to be sex-linked?