Bio chapter 6 &7

An actively dividing cell has six chromosomes. How many sister chromatids are present within this cell at the end of G2 phase?

12

What is the smallest number of traits that are needed to test Mendel's law of independent assortment?

2

A pea plant that is heterozygous for the flower color gene makes gametes. What is the probability that a specific gamete contains the recessive allele for flower color?

50%

Mutation

A change in a gene or chromosome.

gene

A segment of DNA on a chromosome that codes for a specific trait

Phenotype

An organism's physical appearance, or visible traits.

Which of the following choices represents the genotype of an individual diploid organism?

BbCCdd

What type of inheritance pattern is indicated in the body size of the dogs shown below? How does this pattern differ from Mendelian traits?

Body size in dogs follows a pattern of incomplete dominance. With incomplete dominance, heterozygotes display an intermediate phenotype. If a trait is Mendelian, heterozygotes will display the dominant phenotype.

The process of mitosis is thought to have evolved from binary fission. What similarities exist between these processes?

Both processes include DNA segregation.

Allele

Different forms of a gene

A cell has completed S phase and is preparing to divide via mitosis. How is the genetic material arranged in G2 phase?

During S phase the uncondensed chromosomes (chromatin) duplicate, and now there are replicated chromosomes present in the nucleus. The replicated chromosomes consist of two sister chromatids that are held together at a narrowing called the centromere. Early in mitosis the chromatin condenses and tightens into highly compacted chromosomes.

Which of the following statements regarding genes is NOT true?

Genes are found as single copies in cells other than sperm or egg.

The individual who used data from breeding garden peas to discover the patterns of inheritance that form the foundation of modern-day genetics was ________.

Gregor Mendel

Gregor Mendel began his studies by crossing plants that bred true for flower color. One parent bred true for purple flower color and the other parent bred true for white flower color. The flower color purple is dominant and the flower color white is recessive. If Mendel had erroneously crossed purple-flowered plants that were not true-breeding with white-flowered plants, how would this have altered the first generation produced?

If Mendel had crossed plants with purple flowers that were heterozygotes rather than homozygotes, the first generation would have contained a 1:1 mix of purple flowers and white flowers. Half of the offspring would have been heterozygous for the flower color gene. The other half would have been homozygous for the recessive allele. When Mendel crossed plants that were true-breeding for flower color, all of the first generation plants were heterozygotes with purple flowers.

How is Mendel's law of segregation represented in a Punnett square?

Mendel's law of segregation states that two alleles of a given gene separate during meiosis and end up in different gametes. A Punnett square shows the possible ways that alleles of a gene separate to form individual gametes and the possible combinations of those alleles through fertilization.

Which of the following differentiates meiosis from mitosis?

Mitosis is used for the repair of cells, whereas meiosis creates cells for sexual reproduction.

If you were a scientist studying patterns of inheritance in dogs and you were given extensive information about the inheritance of multiple physical traits, such as hair color and height, would you be able to piece together the entire genome of dogs? Explain your answer.

No. The genome would encompass all of the genes in dogs. Multiple physical traits represent phenotypes and would allow you to gather information about some, but not all, genes.

Describe the G0 phase of the cell cycle. Provide an example of what type of cell would enter the G0 stage and propose why this cell would enter the G0 phase

The G0 of the cell cycle is a nondividing state that can last for a few days or through the lifetime of the organism. An example would be nerve cells. Nerve cells must be long enough to accommodate the size of the organism and remain stable throughout the life of the organism, so once they are formed and "full grown" there is probably no need for them to replicate unless there is an injury.

Which of the following would promote a cell to move through the G2 checkpoint?

The genetic information has been duplicated.

Compare and contrast the incidence rate per 100,000 individuals versus deaths per 100,000 individuals for breast cancer in females and for prostate cancer in males presented in the infographic below. What does this suggest about the survivability of breast cancer and prostate cancer?

The incidence rate per 100,000 individuals of prostate cancer is 101.6, while the death rate is only 19.2; roughly 81 percent of the individuals who get prostate cancer survive the experience. The incidence rate per 100,000 of female breast cancer is 123.7, while the death rate is only 20.7; roughly 71 percent of the individuals who get female breast cancer survive the experience. The good news is that for either of these cancers, you are far more likely to survive it than you are to succumb to it!

Why did Mendel analyze thousands of plants while conducting his research?

The likelihood of seeing a clear pattern is higher with a larger data set.

Which processes associated with meiosis ensure genetic diversity in offspring? Name two processes that promote variation and explain how they operate.

There are three processes that allow for genetic variation in the production of offspring. Crossing over between nonsister chromatids of a tetrad exchanges segments of DNA between maternal and paternal homologs. Independent assortment shuffles different combinations of maternal and paternal chromosomes into gametes. A unique egg may then be randomly fertilized with a unique sperm cell.

Which of the following might explain how two separate genes control a single trait?

There are two genes to control two separate steps in a pathway.

Which of the following expresses Mendel's law of segregation?

Two alleles of a gene separate during meiosis and end up in different gametes.

Is it possible for two organisms with the same genotype to have different phenotypes? Explain your answer.

Yes. The expression of the genotype in an individual can be affected by the environment. Phenotype may be controlled by environmental factors. One example is hair color in Siamese cats.

The G0 phase of the cell cycle is distinguished by

an absence of preparation for DNA synthesis.

A researcher is recording the process of bacteria cell division using time-lapse microscopy. Which of the following processes would she be observing?

binary fission

The chromosomes in a homologous pair

carry the same genes.

The last stage in the cell cycle is ________; this consists of ________, which separates the replicated DNA, and ________, which divides and portions the contents of the cell into two new daughter cells.

cell division, mitosis, cytokinesis

Sister chromatids are held together at a constriction point called a ________.

centromere

Most human genetic characters are

controlled by more than one gene.

The leaf color of a certain plant is controlled by one gene. For that gene, the allele G = orange and g = green. You have a plant with orange leaves but do not know whether that plant's genotype is GG or Gg. Which of the following would help you determine the plant's genotype?

cross the plant to a plant with green leaves

A hammer is needed to pound nails into a board. Even if one has the nails, they cannot be used without first getting ahold of a hammer. This is similar to the genetic relationship known as

epistasis.

The figure shown below indicates two Labrador retrievers that are both homozygous recessive for fur color. One dog is brown and the other is yellow due to

epistasis.

The result of ________ is to increase genetic diversity by creating a new diploid individual from haploid cells

fertilization

Mendel used ________ as his research organism to study patterns of genetic inheritance.

garden peas

Genotype

genetic makeup of an organism

Mutations will affect the

genotype, which may affect the phenotype.

Feather color in a certain species of bird is controlled by a pair of alleles that exhibit incomplete dominance. If birds that are homozygous for one allele are black and birds that are homozygous for the other allele are white, then heterozygous birds would be

grey

Cancers are groups of cells that divide rapidly and uncontrollably. Thus, cancer cells

have a relatively short G1 phase.

The possible combinations of alleles in gametes ________ due to independent assortment and crossing over.

increases

According to Mendel's law of ________, when gametes are formed, the separation of alleles for one gene is unrelated to the separation of alleles for other genes.

independent assortment

When tumor cells become anchorage independent and begin to invade other tissues, they are considered to be transformed into cancer cells, also known as ________.

malignant cells

Gametes are produced by meiosis rather than mitosis because

meiosis reduces the chromosome number so that zygotes produced will have one full genome.

In a genetic cross of Gg with Gg guinea pigs, none of the four offspring were gg. This

neither supports nor disproves Mendel's law of independent assortment.

During meiosis I, the chromosome number is reduced to haploid by separating

one of each homologous chromosome pair into two different daughter cells.

The outcome of meiosis is the

production of eggs and sperm.

Which of the following is known to result from the disruption of mitosis and meiosis?

prostate cancer

According to the image below, during which phase of the cell cycle is the genetic material evenly partitioned between daughter cells?

region 6

In Mendel's controlled mating experiments, the individuals produced by crossing two true-breeding parents are referred to as

the F1 generation

Chromosomes

threadlike structures made of DNA molecules that contain the genes

The successful union of one male and one female gamete forms a new single cell known as a

zygote