BIOS 220 Study Guide - Midterm Guide: Sister Chromatids, Dominance (Genetics), House Mouse
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Title: Meiosis Lab
Part 1: Modeling Meiosis Without Crossing Over (reformat as needed)
Take photos of the following stages of your meiosis bead simulation. Insert and label the following images:
Meiosis 1: Prophase I and Metaphase I
Meiosis 2: Metaphase II and Telophase II
Part 2: Modeling Meiosis With Crossing Over (reformat as needed)
Take photos of the following stages of your meiosis bead simulation. Insert and label the following images:
Meiosis with Crossing Over: Metaphase I and Telophase II
Questions – use the lab Introduction, your textbook and other sources to answer the following.
What is the state of DNA at the end of meiosis I? Are the chromosomes replicated or unreplicated? Diploid or haploid?
Why are chromosomes important?
How are Meiosis I and Meiosis II different?
Name two ways meiosis contribute to genetic recombination or genetic variety.
Why do you use non-sister chromatids to demonstrate crossing over? What would happen if you crossed over sister chromatids?
How many chromosomes were present in your simulation when meiosis I started?
Why is it necessary to reduce the chromosome number in gametes, but not in other cells of an organism?
If humans have 46 chromosomes in each of their body cells, determine how many chromosomes you would expect to find in the following:
| Sperm | Egg | Daughter cell after mitosis | Daughter cell after meiosis |
Investigate a disease that is caused by a chromosomal mutation due to nondisjunction. When does the mutation occur? What chromosome is affected? What are the consequences?
Question 10
A microscope image of a cell in interphase is treated with dyes to stain the nucleic acids (DNA and RNA). This image probably displays ______.
| visible nucleoli | ||
| separate visible chromosomes | ||
| visible spindle fibers |
1 points
Question 11
To observe plant cells undergoing mitosis, the best plant tissue to isolate would be ______.
| a section of the root tip | ||
| a section of the mature fruit | ||
| a section of the main stem |
1 points
Question 12
Owen observes a slide containing whitefish blastula sections. He finds a cell with visible spindle lines extending from two points on opposite sides of the cell and chromosomes as small black Xs halfway between the two poles. What stage of the cell cycle is Owen observing?
| anaphase | ||
| metaphase | ||
| prometaphase |
1 points
Question 13
What structural feature can you use to distinguish between DNA-stained onion cells in anaphase and telophase?
| Sister chromatids separate as anaphase ends and telophase begins. | ||
| The vesicles forming a cell plate appear around the onset of telophase. | ||
| The chromosomes are clustered at visible spindle poles during anaphase. |
1 points
Question 14
A carcinogen is any substance or environmental condition that ______.
| increases the frequency of mutation | ||
| causes direct damage to DNA | ||
| inhibits mitosis in cancer cells |
1 points
Question 15
Angelina observes a slide containing whitefish blastula sections. She finds a cell with visible spindle lines extending from two points on opposite sides of the cell and chromosomes as small black Xs halfway between the two poles. What intracellular structure forms each of the two points on opposite sides of this cell?
| a metaphase plate | ||
| a cell plate | ||
| a pair of centrioles |
1 points
Question 16
Which of the following best describes the relationship between interphase and the cell cycle?
| Interphase is a gap between rounds of cell division. | ||
| Interphase comprises a large majority of the cell cycle in almost all cells. | ||
| Interphase comprises a large majority of the cell cycle in slowly and non-dividing cells. |
Question 17
Radiation therapy and chemotherapy are cancer treatments that primarily attack cancer cells through ______.
| activating apoptosis in any rapidly dividing cells to kill off tumor cells | ||
| destroying the blood vessels in cancerous tumors to block the flow of nutrients | ||
| damaging DNA to the extent that cells die if they cannot repair the damage |
If an organism’s diploid chromosome number is 18, how many different possible combinations of homologous chromosomes lining up during meiosis exist for the eggs or sperm produced by that organism?
| A. | 512 | |
| B. | 9 | |
| C. | 18 | |
| D. | 128 | |
| E. | 36 |
At the end of metaphase I, _______________ separate.
| A. | sister chromatids | |
| B. | germ cells | |
| C. | homologous chromosomes | |
| D. | haploid chromatids | |
| E. | centrioles |
Mendel observed that dominant traits
| A. | are seen in all of the F1 hybrid pea plants in his experiments. | |
| B. | are expressed in all plants. | |
| C. | were absent in the F1 generation of pea plants that he used in his experiments. | |
| D. | were the only traits seen in the F2 generation of pea plants in his experiments. | |
| E. | are only expressed in hybrids. |
Cytokinesis in plant cells differs from cytokinesis in animal cells because
| A. | there is no difference. | |
| B. | in plant cells, the cell plate must also divide into two parts. | |
| C. | the contractile protein, actin, is important only in plant cells. | |
| D. | plant cells have a rigid cell wall. | |
| E. | a contractile ring forms only in plant cells. |
Sickle cell anemia is an example of what type of inheritance?
| A. | complete dominance | |
| B. | incomplete dominance | |
| C. | codominance | |
| D. | multiple alleles | |
| E. | recessive dominance |
Which of the following statements is true:
| A. | The dominant allele is masked in homozygous dominant individuals. | |
| B. | With recessive genetic disorders, if both parents are carriers, the offspring will all be affected. | |
| C. | In carriers, the recessive allele causes an intermediate phenotype. | |
| D. | In recessive genetic disorders, the mother and/or father of an affected individual must also be affected. | |
| E. | With dominant genetic disorders, the mother and/or father of an affected individual must also be affected. |
Skin cancers typically develop in the
| A. | upper layers of the epidermis. | |
| B. | lower layers of the dermis. | |
| C. | subcutaneous layer. | |
| D. | lower layers of the epidermis. | |
| E. | upper layers of the dermis. |
Duchenne muscular dystrophy (MD) is inherited from an X-linked recessive allele. What is the probability that a son with Duchenne MD inherited this disease from his biological father?
| A. | 1/2 | |
| B. | 0 | |
| C. | 1/16 | |
| D. | 1/4 | |
| E. | 1/8 |
The genetic makeup of a particular trait in an individual is its
| A. | genotype. | |
| B. | heterozygosity. | |
| C. | phenotype. | |
| D. | filial. | |
| E. | dominance. |
What structure holds the sister chromatids to the spindle fibers?
| A. | chromatin | |
| B. | kinetochore | |
| C. | MPF | |
| D. | centromere | |
| E. | cyclin |
If you view a cell in which the genetic material is beginning to be visible as separate bodies, and the nucleus has disappeared from view, you may surmise that the cells is in
| A. | telophase. | |
| B. | anaphase. | |
| C. | interphase. | |
| D. | metaphase. | |
| E. | prophase. |
Gregor Mendel was successful in his analysis of the genetics of pea plants because
| A. | he examined and analyzed both the F1 and F2 generations. | |
| B. | he studied the parental plants to determine their differences. | |
| C. | he decided to only look at his results in an objective manner. | |
| D. | he studied a trait that had a strange inheritance pattern. | |
| E. | pea plants have genetics different from other organisms. |
Tall corn plants (T) are dominant to dwarf plants (tt). Solid green leaves (G) are dominant to leaves with a white tip (gg). A cross between two corn plants yielded the following phenotypes: 51 tall plants with a white tip on their leaves; 43 dwarf plants with solid leaves; 48 dwarf plants with white tips on their leaves; 45 tall plants with solid leaves. What are the genotypes of the parents that produced these plants?
| A. | None of the above | |
| B. | TtGg x Ttgg | |
| C. | ttGG x TTgg | |
| D. | TtGg x TtGg | |
| E. | TtGg x ttgg |
In humans, a gene that has been identified as causing a type of skin cancer is the
| A. | superwoman echidna. | |
| B. | mutant superman. | |
| C. | sonic hedgehog. | |
| D. | mutant mole rat. | |
| E. | superhero aardvark. |
The segregation principle states that in sexually reproducing diploid organisms the two copies of each gene
| A. | segregate from each other during meiosis. | |
| B. | must always be the same allele. | |
| C. | separate from each other during mitosis. | |
| D. | will both wind up in either the sperm or egg. | |
| E. | move together as a unit during meiosis. |
In what phases is the genetic material in the cell correctly referred to as chromatids?
| A. | metaphase and telophase | |
| B. | anaphase and metaphase | |
| C. | interphase and telophase | |
| D. | interphase and prophase | |
| E. | metaphase and prophase |
Consider two traits for an organism, determined by two genes, each of which is governed by at least two alleles. In the case of a dihybrid individual, the gametes formed will be of either the parental type or the recombinant type. Recombinant type gametes are formed because of
| A. | the principle of dihybrids. | |
| B. | multiple alleles. | |
| C. | heterozygosity. | |
| D. | incomplete dominance. | |
| E. | independent assortment. |
An allele is
| A. | an alternate form of a gene. | |
| B. | always recessive. | |
| C. | the main factor determining a trait. | |
| D. | always one of a pair. | |
| E. | the dominant form of a gene. |
After the DNA is replicated, and it condenses in prophase, two identical rods of DNA are seen. These are
| A. | spindle fibers. | |
| B. | kinetochores. | |
| C. | chromatids. | |
| D. | chromatin. | |
| E. | centromeres. |
Special cells found in the gonads that give rise to gametes upon division are called
| A. | egg cells. | |
| B. | somatic cells. | |
| C. | germ cells. | |
| D. | stem cells. | |
| E. | basal cells. |