bio 5

Trait

A characteristic that an organism can pass on to its offspring through its genes.

character

A heritable feature that varies among individuals

Dominant

An allele that is always expressed

Recessive

An allele that is masked when a dominant allele is present

Heterozygous

An organism that has two different alleles for a trait (A,a)

Homozygous

An organism that has two identical alleles for a trait, (A,A)

How does cytokinesis occur in a dividing animal cell?

By the formation of a cleavage furrow

Interphase

Chromosomes are duplicated in preparation for cell division. The cytoplasm doubles, increasing the overall size and volume of the cell.

If it were to be stretched out, the DNA in one of your cells would be taller than you. How does such a large quantity of DNA fit within the nucleus of one of your cells?

DNA is associated with proteins that compact the DNA to form a package called chromatin.

What do we call a genetic cross that follows two separate characters, such as pea seed color and pea seed shape?

Dihybrid cross

A breeder wants to set up a program to produce zebrafish with long fins. Having long fins is a dominant trait compared to the short-finned wild type. Before she can market her zebrafish, she needs to perform a test cross on the long-finned fish she plans to use as a breeder. How can she tell whether her fish are homozygous or heterozygous for the long-finned trait?

Do several test crosses between the long-finned fish and the short-finned fish; if the offspring are always long finned, the long-finned parent is probably homozygous.

Guar are increasingly rare wild oxen found in Asia. How would you clone this animal?

Fusing a guar cell nucleus with an egg cell from a domestic cow that has had its nucleus removed

Imagine that five hypothetical genes are arranged on a chromosome in the following order: G--H--I--J--K. Which two genes are most likely to have a crossover occur between them?

G and K

Gorillas have 48 chromosomes. How does the number of chromosomes in a gorilla sperm compare with that of a human sperm?

Gorilla sperm have one more chromosome than human sperm. Human sperm have 23 chromosomes, gorilla sperm have 24.

What is Mendel's law of independent assortment?

Independent assortment means that each pair of alleles segregates independently of the other pairs of alleles.

What is the role of transcription factors?

Initiate gene expression

In a human, which of the following could be identified by the use of a karyotype?

Klinefelter syndrome, where a male has two X and one Y chromosomes

Mendel formulated his principles of inheritance based on _____.

NOT

Fur color in rabbits is controlled by multiple alleles. What does this mean?

Rabbit fur color is controlled by a single gene, but there are multiple versions of that gene.

Which of the following statements regarding the gene for sickle-cell disease must be true?

Sickle-cell is a mutant trait, but we cannot say whether it is dominant or recessive.

Cytokinesis

The cell divides into two offspring cells, each with a complete set of chromosomes from the parent cell.

Mitosis

The duplicated chromosomes separate and are distributed to two offspring nuclei.

The inheritance pattern for red-green color blindness is different for males compared to females. Red-green color blindness is much more common in males than in females. What does this suggest about the gene for red-green color blindness?

The gene for this trait is located on the X sex chromosome.

Alleles

alternative versions of a gene

When are the chromosomes of a cell duplicated?

before a cell divides

Sickle-cell disease is caused by a recessive form of hemoglobin. Two parents that do NOT have the disease give birth to a child that does. What are the genotypes of the mother and father for the hemoglobin gene?

both parents are heterozygous

Two alleles of the same gene ________.

can be the same or can be different

Imagine that eye color in cats is controlled by a single gene and that there are two alleles: black eyes and orange eyes. All the offspring of a cross between a black-eyed cat and an orange-eyed cat have black eyes. This means that the allele for black eyes is __________ the allele for orange eyes.

dominant to

What is crossing over?

exchange of genetic material between homologous chromosomes

What is the chromosome abnormality that causes Down syndrome?

extra 21 chromosome

If a woman with curly hair and a man with straight hair have a child with wavy hair, the gene for this characteristic of hair shows __________.

incomplete domience

Random orientation of homologous pairs of chromosomes during meiosis I results in alternative arrangements that contribute to genetic variation in offspring. This is called __________.

independent assortment

What process involving cell division results in daughter cells that are NOT identical to the parent cell?

sexual reproduction

As mitosis begins, __________ are linked together at the centromere.

sister chromatids

cells that undergo mitosis

somatic cells

interphase, prophase, metaphase, anaphase, telophase/cytokenisis

spindle forms, chromosomes line up, split apart, nuclear envelope is made

Like mitosis, meiosis involves duplication of the chromosomes before division starts. However, there are __________ rounds of cell division during meiosis and __________ during mitosis.

two;one