1.
Name the phase during which the mitosis of the chromosomes line up along the middle of the dividing cell.
Correct Answer
B. MetapHase
Explanation
During metaphase, the chromosomes align themselves along the equatorial plane of the cell, forming a single line called the metaphase plate. This alignment ensures that each daughter cell will receive an equal number of chromosomes during cell division. The spindle fibers attach to the centromeres of the chromosomes, allowing them to be pulled apart during the subsequent phase of mitosis. Therefore, metaphase is the correct phase during which the chromosomes line up along the middle of the dividing cell.
2.
The two main stages of the cell cycle are called:
Correct Answer
A. Mitosis and interpHase
Explanation
The cell cycle consists of two main stages: mitosis and interphase. Mitosis is the process of cell division where the nucleus divides into two identical daughter cells. Interphase is the period between cell divisions where the cell grows, duplicates its DNA, and prepares for the next division. These two stages are crucial for the growth and reproduction of cells.
3.
The first phase of mitosis is called ___________.
Correct Answer
A. PropHase
Explanation
The correct answer is prophase. Prophase is the first phase of mitosis, where the chromosomes condense and become visible, the nuclear membrane breaks down, and the spindle fibers start to form. During prophase, the genetic material is prepared for division and the cell begins to transition into the next phase of mitosis.
4.
Sea stars are genetically different from each other and from their parents. These genetic differences are the result of:
Correct Answer
D. Sexual reproduction
Explanation
Genetic differences in sea stars and their differences from their parents primarily result from sexual reproduction and asexual reproduction. Sexual reproduction involves the combination of genetic material from two parents, resulting in offspring with genetic diversity.
5.
A protein called p53 can keep cells from dividing. To prevent cell division, this protein most likely stops ___________.
Correct Answer
B. Mitosis
Explanation
The protein p53 is known to prevent cell division. Mitosis is the process by which cells divide and replicate themselves. Therefore, it is most likely that p53 stops mitosis to prevent cell division. Osmosis is the movement of water across a selectively permeable membrane, respiration is the process of converting glucose into energy, and mutation refers to changes in the DNA sequence. None of these processes are directly related to cell division, making mitosis the most likely option.
6.
When the DNA in a cell is uncoiled and spread throughout the nucleus, this process is called chromatin. State true or false.
Correct Answer
A. True
Explanation
When the DNA in a cell is uncoiled and spread throughout the nucleus, it forms a complex called chromatin. This process allows the DNA to be accessible for gene expression and other cellular processes. Therefore, the statement is true.
7.
DNA in a cell is copied during:
Correct Answer
D. S pHase
Explanation
During the S phase of the cell cycle, DNA replication occurs. This is the phase where the cell's DNA is copied to produce two identical sets of chromosomes. The S phase is a critical step in cell division as it ensures that each daughter cell receives a complete and accurate copy of the genetic material. Therefore, the correct answer is S phase.
8.
The spindle fibers are produced by the ________.
Correct Answer
A. Centrioles
Explanation
Centrioles are responsible for producing spindle fibers. Spindle fibers are essential for cell division as they help separate the chromosomes and ensure that each daughter cell receives the correct number of chromosomes. Therefore, centrioles play a crucial role in the process of cell division by producing spindle fibers.
9.
Cleavage furrows form in which type of cells?
Correct Answer
C. Animal
Explanation
Cleavage furrows are a feature of animal cells during cell division, specifically during cytokinesis. They are formed as the cell membrane pinches inwards, dividing the cytoplasm into two separate daughter cells. This process is essential for the growth and development of animal organisms. In contrast, bacteria and plants do not form cleavage furrows during cell division. Therefore, the correct answer is animal.
10.
Cells spend most of their time in _____ phase.
Correct Answer
D. InterpHase
Explanation
The correct answer is interphase because during interphase, cells spend the majority of their time preparing for cell division. This is the longest phase of the cell cycle and is characterized by growth, DNA replication, and preparation for mitosis. Cytokinesis is the final stage of cell division where the cytoplasm divides. Prophase is the first stage of mitosis where the chromosomes condense and become visible. Mitosis is the process of cell division where the replicated chromosomes are separated into two daughter cells.