Question | Answer |
Most of an organism's DNA is carried by its? | chromosomes |
Replication of chromosomal DNA occurs... | before a cell divides
This ensures that genetic material will be appropriately distributed to the daughter cells. |
The cell cycle is a series of events that occur in which order? | G1, S, G2, mitosis, cytokinesis |
What is the correct order for the four main stages of mitosis? | prophase, metaphase, anaphase, telophase |
What must happen before a cell can begin mitosis? | The chromosomes must be duplicated. |
The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis? | Prophase |
The chromosomes line up in the center of the cell during which phase of mitosis? | Metaphase |
The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis? | Anaphase |
The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis? | Telophase |
At the end of the mitotic (M) phase, the cytoplasm divides in a process called ? | cytokinesis |
In sexually reproducing multicellular organisms, the main functions of mitosis are... | - tissue repair/replacement of damaged cells
- growth and development |
Which events occur during prophase? | - Chromosomes condense and are attached to spindle fibers.
- The nuclear envelope breaks down. |
Cytokinesis... | finishes mitosis by dividing the cytoplasm and organelles of the original parent cell into two separate daughter cells |
During _____, the cell carries out its normal functions and the chromosomes are thinly spread out throughout the nucleus. | interphase |
Looking through a light microscope at a dividing cell, you see two separate groups of chromosomes on opposite ends of the cell. New nuclear envelopes are taking shape around each group. The chromosomes then begin to disappear as they unwind. You arewitnessing _____. | telophase |
What is the risk that someone in the United States will die of cancer? | 1 in 5 |
The function(s) of meiosis is/are _____. | reproduction (production of gametes) |
Looking through a light microscope at a cell undergoing meiosis, you see that the chromosomes have joined into XX-shaped tetrads. These tetrads are lined up along a plane that runs through the center of the cell. This cell is in _____. | meiosis I |
Meiosis starts with _____ cells and produces _____ gametes. | diploid ... haploid |
Meiosis is typically accomplished in _____. | three steps. All of the chromosomes are duplicated in a diploid cell, and then there are two cell divisions to produce a total of four haploid gametes. |
The _____ separate in meiosis I; the _____ separate in meiosis II. | homologous chromosomes ... sister chromatids |
Meiosis starts with a single diploid cell and produces | four haploid cells |
A cell preparing to undergo meiosis duplicates its chromosomes during | interphase |
During prophase I of meiosis, | homologous chromosomes stick together in pairs. |
The correct order of events during meiosis is | prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II. |
During meiosis, segments of nonsister chromatids can trade places. This recombination of maternal and paternal genetic material is a key feature of meiosis. During what phase of meiosis does recombination occur? | prophase I
Segments of nonsister chromatids trade places during prophase I, resulting in recombination. |
Meiosis and cytokinesis result in the formation of __________. | four haploid cells |
Which processes lead to most genetic variation in sexually reproducing organisms? | - crossing over
- random fertilization
- independent orientation of chromosomes in meiosis |
Orientation of homologous pairs of chromosomes at metaphase I results in alternative arrangements that contribute to genetic variation in offspring. The orientation is called _____. | independent assortment |
Crossing over is __________. | the exchange of corresponding portions of homologous chromosomes |
Sexual reproduction requires the cellular process of _____ followed by _____. | meiosis ... fertilization
Meiosis produces gametes, and a gamete from one individual unites with a gamete from another individual during fertilization. |
A typical body cell with 23 pairs of chromosomes is called a _____. | somatic cell |