1.
Check all the stagess of MITOSIS (not the whole cell cycle).
Correct Answer(s)
B. PropHase
C. MetapHase
D. AnapHase
E. TelopHase
Explanation
The stages of mitosis are prophase, metaphase, anaphase, and telophase. During prophase, the chromosomes condense and the nuclear membrane breaks down. In metaphase, the chromosomes line up along the center of the cell. Anaphase is characterized by the separation of sister chromatids, which are pulled to opposite poles of the cell. Telophase is the final stage, where the nuclear membrane reforms and the chromosomes decondense. Cytokinesis, the division of the cytoplasm, occurs after mitosis is complete.
2.
Meiosis starts with one diploid cell and ends up with ______.
Correct Answer
C. 4 haploid cells
Explanation
Meiosis is a type of cell division that occurs in sexually reproducing organisms. It starts with one diploid cell, which means it has two sets of chromosomes, and ends up with four haploid cells. Haploid cells have only one set of chromosomes, which is important for sexual reproduction as it allows for the combination of genetic material from two parents. Therefore, the correct answer is 4 haploid cells.
3.
If an animal has 22 chromosomes in its body cells how many chromosomes will it have in the zygote that it developed from?
Correct Answer
B. 22
Explanation
When an animal develops from a zygote, it inherits half of its chromosomes from each parent. Therefore, if an animal has 22 chromosomes in its body cells, the zygote it developed from will also have 22 chromosomes.
4.
Check the boxes next to the cells that are gametes.
Correct Answer(s)
A. Sperm
C. Egg
Explanation
The gametes are the reproductive cells that fuse during fertilization to form a zygote. Sperm and egg cells are both gametes because they are specialized cells involved in sexual reproduction. The zygote is the result of the fusion of a sperm and an egg, so it is not a gamete. Body cells, also known as somatic cells, are not involved in reproduction and therefore are not gametes.
5.
Egg and sperm are sex cells, called ___.
Correct Answer
A. Gametes
Explanation
Egg and sperm are sex cells, called gametes. Gametes are specialized cells that are involved in sexual reproduction. They are haploid cells, meaning they contain half the number of chromosomes compared to other cells in the body. During fertilization, the egg and sperm fuse together to form a zygote, which is the beginning stage of a new individual. Diploids, on the other hand, refer to cells or organisms that have two sets of chromosomes.
6.
Crossing over is where genes from one chromosome switch places with genes from its pair during meiosis. This results in increased ____.
Correct Answer
D. Variation
Explanation
During crossing over in meiosis, genes from one chromosome exchange places with genes from its homologous pair. This process leads to the creation of new combinations of alleles, resulting in genetic variation within a population. This variation is essential for evolution and adaptation as it introduces new traits and characteristics, increasing the chances of survival and the ability to adapt to changing environments.
7.
Polyploidy is normal and healthy in _____ but usually deadly in _____.
Correct Answer
B. Plants, animals
Explanation
Polyploidy refers to the condition of having multiple sets of chromosomes. In plants, polyploidy is a common occurrence and is often advantageous, leading to increased vigor and adaptability. Many plant species have evolved through polyploidy. On the other hand, polyploidy in animals is usually lethal and not a normal occurrence. Animals have a more strict regulation of their genetic material, and any deviation from the normal chromosome number can disrupt essential biological processes, leading to developmental abnormalities and ultimately death.
8.
If a mistake in meiosis results in an extra chromosome #21 in humans, the resulting offspring will have what disorder?
Correct Answer
C. Down's syndrome
Explanation
If a mistake in meiosis results in an extra chromosome #21 in humans, the resulting offspring will have Down's syndrome. Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21. This condition leads to developmental delays, intellectual disabilities, distinctive facial features, and potential health issues such as heart defects and respiratory problems.
9.
If a haploid sperm fertilizes a haploid egg a diploid zygote is formed which grows into a new individual through continued mitosis. If the zygote has 10 chromosomes, how many chromosomes did the egg have?
Correct Answer
5, five
Explanation
When a haploid sperm fertilizes a haploid egg, a diploid zygote is formed. This means that the zygote will have a complete set of chromosomes, with one set coming from each parent. Since the zygote has 10 chromosomes, it can be inferred that each parent contributed 5 chromosomes. Therefore, the egg must have had 5 chromosomes.
10.
A normal body cell has two of each chromosomes. Chromosomes in a pair are said to be _____.
Correct Answer
B. Homologous
Explanation
Homologous chromosomes are pairs of chromosomes that have the same genes in the same order, although they may have different versions of those genes. In a normal body cell, there are two copies of each chromosome, one from each parent, making them homologous. This allows for genetic diversity and the ability to inherit traits from both parents.