Mastering
What is the typical result when a diploid cell undergoes meiosis?
four haploid cells The two cell divisions of meiosis, I and II, produce four haploid daughter cells, which are not genetically identical to the diploid parent cell.
During anaphase II, __________.
sister chromatids separate and migrate toward opposite poles This occurs during anaphase II of meiosis and during anaphase in mitosis
During which phase of mitosis does the nuclear envelope re-form?
telophase
Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are
homologous chromosomes.
Mendel's principle of independent assortment applies to the __________.
independent assortment of alleles of one gene relative to the alleles of any other gene The key idea of independent assortment is the independent transmission into gametes of alleles of two or more genes.
The -______ is the genetic makeup of an organism.
genotype
Imagine that beak color in a finch species is controlled by a single gene. You mate a finch homozygous for orange (pigmented) beak with a finch homozygous for ivory (unpigmented) beak and get numerous offspring, all of which have a pale, ivory-orange beak. This pattern of color expression is most likely to be an example of
incomplete dominance.
A __________________ ____________is an abnormally growing mass of cells that is actively spreading through the body. Amalignant tumoris an abnormally growing mass of cells that is actively spreading through the body.
malignant tumor
A genetic cross involving parents that differ in a single character is called a ______________
monohybrid cross
A ____________ is one particular variation of a character.
trait
Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as
true-breeding
Justin has type A blood and his wife Brittany has type B blood. Justin's parents both have type AB blood, and Brittany's parents also both have type AB blood. What are the chances that Justin and Brittany's son Theodore has type A blood?
0%
Pea flowers may be purple (P) or white (p). Pea seeds may be round (R) or wrinkled (r). What proportion of the offspring from the cross PpRr × PpRr are expected to have white flowers and wrinkled seeds?
1/6 Pp × Pp would produce 3/4 purple and 1/4 white. Rr × Rr would produce 3/4 round and 1/4 wrinkled. (1/4)(1/4) = 1/16 would have white flowers and wrinkled seeds.
Most human genes come in alternate versions called _________________
alleles
In some cats, black coat color (B) is dominant over brown (b) and a striped fur pattern (S) is dominant over a marbled fur pattern (s). You rescued a black striped cat from an animal shelter but could not determine its exact genotype. To do so, you mated the cat with a brown marbled cat. The mating produced 3 brown marbled, 2 brown striped, 2 black marbled, and 3 black striped. Immediately, you concluded the genotype of your rescued cat was
BbSs.
At the end of the mitotic (M) phase, the cytoplasm divides in a process called _________________.
Cytokinesis is the division of the cytoplasm that occurs in conjunction with telophase, the last phase in mitosis.
Two individuals decide to have children. The expected blood group genotypes are 50% of blood type A, and 25% each of blood types AB and B. What genotypes are the parents?
IAi x IAIB Since blood groups show codominance, the child of blood type A must be either IAIA or IAi. The child of blood type B must be either IBIB or IBi. The child of blood type AB can only be IAIB. Because there are more offspring expected with blood type A, we know that an A allele is being contributed from both parents. By reversing the Punnett square, the parents' genotypes are observed to be IAi and IAIB.
Two individuals decide to have children. The expected blood group genotypes are 50% of blood type A, and 25% each of blood types AB and B. What genotypes are the parents?
IAi x IAIB Since blood groups show codominance, the child of blood type A must be either IAIA or IAi. The child of blood type B must be either IBIB or IBi. The child of blood type AB can only be IAIB. Because there are more offspring expected with blood type A, we know that an A allele is being contributed from both parents. By reversing the Punnett square, the parents' genotypes are observed to be IAi and IAIB.
Which of the following statements correctly describes the behavior of a tetrad during anaphase I of meiosis?
It splits into two pairs of sister chromatids, and one pair goes to each pole of the dividing cell.
The chromosomes line up in the center of the cell during which phase of mitosis?
Metaphase occurs in the middle of mitosis, when the chromosomes line up in the middle of the cell.
__________________ is the spread of cancer cells from their site of origin to other sites in the body.
Metastasis
The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?
Prophase is the first phase of mitosis, when the centrosomes begin moving toward opposite poles and the nuclear envelope breaks up.
What must happen before a cell can begin mitosis?
The chromosomes must be duplicated Before mitosis can begin, the chromosomes, or genetic material, must be copied, which occurs during interphase.
The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?
Sister chromatids separate and start their migration toward opposite poles during anaphase
The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?
Telophase is the final phase of mitosis, when the chromosomes have arrived at the poles and the nuclear envelopes of the two new cells form.
Which of the following statements regarding the cell cycle control system is false? The cell cycle control system operates independently of the growth factors. The cell cycle control system triggers and controls major events in the cell cycle. The cell cycle control system receives messages from outside the cell that influence cell division. The cell cycle control system includes three key checkpoints to complete a cell cycle.
The cell cycle control system operates independently of the growth factors. ******because... The cell cycle control system receives messages from outside and inside the cell, triggers and controls major events in the cell cycle, and includes three key checkpoints to complete a cell cycle.
During cell division, what role do centrosomes play?
They organize the microtubules. The centrosomes are the microtubule-organizing centers of the cell
Which of the following indicates Turner syndrome? XXY XXX XYY XO
XO This is the sex chromosome complement of an individual with Turner syndrome.
A ____________ _____________ is a lump of abnormal cells that, although growing out of control, remains at its original site.
benign tumor
An individual with a malignant tumor is said to have ___________.
cancer
The most common type of cancer is a _______________; this type always originates in tissues that line organs.
carcinoma
A ________ is an inherited feature that varies from individual to individual.
character
If an organism has two non-identical versions of a gene, the one that is expressed in the organism is called the _____________ allele.
dominant
DdEe pea plants can produce _____ type(s) of gametes, but a ddee plant can produce _____ type(s) of gametes.
four ... one DdEe individuals can produce the following gametes: DE, De, dE,de. A ddee plant can produce only de gametes
The physical traits of an organism are called its _____
phenotype
A karyotype is most like
photographs of every couple at a high school prom.
Which processes lead to most genetic variation in sexually reproducing organisms? Select all that apply. random fertilization crossing over independent orientation of chromosomes in meiosis cytokinesis
random fertilization crossing over independent orientation of chromosomes in meiosis
If an organism has two non-identical versions of a gene, the one that is not expressed in the organism is called the ___________ allele.
recessive
