People who have been exposed to excessive radiation often experience mutations. If these mutations only occur in somatic cells, these people may-
Chromosome A contains genes for an eye color of hazel. Chromosome B contains genes for hair color of brown, and chromosome C contains genes for an eye color of blue.
Cells grown in a petri dish tend to divide until they form a thin layer covering the bottom of the dish. If cells are removed from the middle of the dish, the cells bordering the open space will begin dividing until they have filled the empty space. What does this experiment show?
The diagram below represents division of a cell that produces two daughter cells.
Which statement most likely describes the daughter cells produced?
In terms of the cell, cancer cells differ from normal cells in which of the following ways?
I. Cancer cells pass through the phases of the cell cycle in sequences different from that of normal cells.
II. Cancer cells do not stop dividing when they come in contact with other cells as normal cells do.
III. Cancer cells are able to divide an indefinite number of times, while normal cells divide a limited number of times.
Cells and the organisms they make up reproduce through cell division. Some organisms reproduce through mitosis, while others reproduce through meiosis and fertilization. What advantage does meiosis give to organisms that reproduce sexually?
Which of the following is the best explanation for why the chromosome number is an even number in each of these organisms?
What is the significance of anaphase in this process?
A photomicrograph of onion root tip cells during mitosis is shown below.
Which phase of mitosis is occurring in the cell indicated by the arrow?
The diagram below represents the cell cycle.
When cells leave the cell cycle, they exit during G1 phase and then enter G0 phase, a resting period. Most normal cells can leave G0 phase and re-enter the cell cycle at G1 phase before entering S phase. Cancer cells are different because they cannot enter G0 phase and are likely to do with which of the following?
The diagram below represents processes involved in human reproduction.
Which row in the chart below correctly identifies the processes represented by the letters in the diagram?
Using the picture below, identify the stage represented
Strawberries can reproduce by means of runners, which are stems that grow horizontally along the ground. At the region of the runner that touches the ground, a new plant develops. The new plant is genetically identical to the parent because:
As a result of mitosis, each of the two new cells produced from the parent cell during cytokinesis:
All cells in an embryo have the same DNA. However, the embryonic cells form organs, such as the brain and the kidneys, which have very different structures and functions. These differences are the result of:
The diagram above shows the process of meiosis. The segregation that occurs during meiosis results in a:
A cell resulting from the fertilization of an egg begins to divide. Two cells are formed that normally remain attached and could develop into a new individual. If the two cells become separated, which statement describes what would most likely occur?
You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph.
Which sample might represent an animal cell in G2 phase of the cell cycle?
You have isolated DNA from three different cell types of an organism, determined the relative DNA content for each type, and plotted the results on the graph.
Which sample might represent a cell at the end of Meiosis II?
Which of these must occur during the S phase of the cell cycle so that two daughter cells can be produced during M phase?
Which phrase best describes a process represented in the diagram?
The diagram below shows four stages of a cell undergoing the cell cycle.
Which of the following is the correct sequence of stages as they occur in the cell cycle?
The number in each circle below represents the chromosome number of the cell. Which diagram represents the production of offspring by an asexually reproducing organism?
The number in each circle below represents the chromosome number of the cell. Which diagram represents the end of Meiosis I?
The sorting and recombining of genes during meiosis and fertilization usually leads to the production of
DNA changes form over the course of the cell cycle. What is the difference between the terms chromosome, chromatin, and chromatid?
Which statement is true of both mitosis and meiosis?
Crossing-over between non-sister chromatids during meiosis is significant in heredity. This process most likely leads to an increase in which of the following?
Which diagram correctly represents a step in the normal process of human reproduction?
Researchers combined sequences of fruit-fly DNA from a gene for a particular trait with frog DNA. The mixture was heated to separate the DNA strands. Cooling allowed the single strands to form pairs. The researchers observed that some of the fruit-fly DNA paired with frog DNA.
The results provide evidence that —
People who have leukemia, a cancer that affects white blood cells, are often given Cytarabine. This drug inhibits the synthesis of DNA. Which phase of the cell cycle is most affected by Cytarabine?
Which of these is the direct result of an error in the transcription of a DNA nucleotide?
A model of a biological process is shown.
What is the purpose of this process?
What is the role of mRNA in expressing specialized structures?
A mutation in which types of cells would only affect the organism and not future generations?
In the early 1900s, Thomas Hunt Morgan was among the first scientists to contribute to the chromosome theory of heredity. Morgan’s investigations into heredity in fruit flies led him to propose that the event represented in the diagram sometimes occurs.
Which statement about the event represented in the diagram is valid?
Two biomolecules are shown.
Which of the following best describes these biomolecules?
This model of the cell cycle includes two arrows that each represent a process in the cycle.
What do the two arrows represent?
A certain mutation in the gene for hemoglobin results in the red blood cells becoming sticky, rigid, and irregularly shaped. These irregularly shaped red blood cells block the flow of blood throughout the body. A single base mutation is responsible for these irregularly shaped blood cells.
Which of these mutations most likely results in the mutated hemoglobin gene?
The model represents the change in the DNA content of a cell during the cell cycle.
Which part of the model represents the S phase?
Human body cells each have 46 chromosomes in their nuclei. Meiosis is necessary in order to ensure that each gamete produced in the human body has —
Some students used information they gathered from lab investigations to prepare a table. They entered the table in their lab notebooks.
Which of these correctly identifies the two cells described in the table?
The diagram shows cells in different phases of mitosis. A student is trying to find a cell in a particular phase of mitosis. The student is looking for evidence that spindle fibers are separating the chromosomes to ensure that each new nucleus has one copy of each chromosome.
Which cell is in the phase of mitosis that the student is searching for?
Table 1 shows the stage and number of cells and chromosomes per cell at the end of the stage in a 2n= 24 organism.
Which of the following statements correctly describes the chromosomes in each daughter cell at the end of meiosis I?
Discuss TWO differences between spermatogenesis in male humans and oogenesis in female humans. (2 marks)
