Unique haploid cells are produced in part by crossing over, which occurs in prophase I on meiosis. Crossing over is the process by which during synapsis, homologous chromosomes exchange sets of DNA, resulting…
Diplotene - pachytene - leptotene - diakinesis - zygotene Bloom's Level: 1. Remember Learning Outcome: 02.04.01 List and describe the phases of meiosis. Section: 02.04 Topic: Meiosis 32. The physical structure that is formed when two chromatids cross over is called a(n) _______. A. synaptomenal complex B. bivalent C. karyotype D. chiasma Bloom's Level: 1.…
Inside the ovary there are ovules that contain megasporangium (2n) that produce megasporocytes (2n) that can undergo meiosis to produce four megaspores (n). Only one of the megaspores survives, remaining inside the ovule. Integuments surround the ovule closing off nearly all of the ovule except a small opening, known as the micropyle. The process creates the female gametophyte, the embryo sac, which among other things contains an egg and two polar nuclei. Wind or pollinators causes the pollen grain to land on the stigma where it forms the pollen tube which allows the two sperm to travel into the embryo sac.…
If there is crossing over between the centromere and the ascospore color gene, the chromatids will separate so each has a different allele. This will cause the first and last two ascospores to have different phenotypes. After meiosis II and mitosis, the tetrad will have an unrecombined order in terms of ascospore color including 2:2:2:2, 2:4:2, or any other non 4:4 sequence. This is termed the second division segregation (Glase, 1995). The amount of each in the sample allow for the data to figure out the gene-centromere…
Telophase/cytokinesis occurs when there is no longer a mother/father pair together, After the completion of meiosis I, the cells are no longer diploid cells, but rather haploid cells. Meiosis II also has four phases including prophase II, metaphase II, anaphase II, and telophase II/ cytokinesis. Prophase II occurs when spindle fibers reform and attach to the centromeres. Metaphase II consist of the chromosomes lining up to prepare for the division of centromeres in the next phase.…
During metaphase, mitotic spindles move to the opposite poles. Then the chromosomes are pulled by the kinetochore microtubules at the metaphase plate. Sister chromatids are still attach to the kinetochore microtubules. In anaphase, two sister chromatids are separated, and become full-fledged chromosomes. The separated daughter chromosomes…
Lastly, the ribosomes are the basic necessity to the process of protein synthesis. 2. Meiosis is a process where specialized cells split and evolve, becoming sperm or egg cells. It occurs in sexually reproducing organisms. Also, recombination occurs with the pairing of homologous chromosomes in an exchange of genetic information.…
After being given instructions for the blood work and necessary health teachings, I offered to further discuss how the fertilized egg in her body would develop into a mature organism. She obliged. G1, the gap 1 phase is where the cell grows and carries out metabolic processes. S, the synthesis phase where the cell replication of its DNA occurs. G2, the gap 2 phase is where the cell continues to grow making preparations for the second major process: M, the mitosis.…
What is crossing over? What is independent assortment? How do those two events increase variation in a population? Crossing-over involves the exchange of a portion of chromosomes from one member of the homologous pair to the other. It is believed that crossing over occurs several times on each homologous pair during each occurrence of meiosis.…
When I return to school after summer break I will take AP Biology 2. I enjoyed my experience with Honors Biology so I decided to continue it at a higher level. In order to properly introduce myself I will be discussing my family, my previous science courses, and my purpose and goals in taking this class. I am a only child and have a small family.…
Mitosis is part of the cell cycle; it is a process where the cell nucleus is separated into two identical sets of chromosomes. Mitosis is an important…
Describe the structure and function of a lysosome. Lysosomes are a cell organelle, translating as an independent structure within a cell, possessing a specific structure and function. For a lysosome its functions include; digestion of intracellular or extracellular material, nutrition from digested macromolecules and defence/protection from harmful substances. Lysosomes are variable from cell to cell in terms of shape and size but are conventionally spherical or oval shaped, 0.5µm in diameter and around 0.5-5µm in length.…
3.1 1. The improvements in the microscope help scientists see the cells better and distinguish the different organelles inside the cell. 2. Prokaryotic cells do not have a nucleus and most internal structures that eukaryotic cells. 3.…
While in the Meiosis there takes cell div ision two times but chromosomes divides only single time. 2) Mitosis usually occurs in the somatic cells. While Meiosis takes place in the germ cells. 3) Mitosis generally takes place in both sexually and asexually reproducing organisms. While we should know that Meiosis only occurs in sexually reproducing organisms.…
1.1 Describe stages of development from conception to birth. When an egg is fertilised it is a single cell called a Zygote, in the next 24-36 hours the single cell will divide into two cells, 12 hours after it will divide into four cells, and will carry on dividing which forms a cluster of cells which are called a monula. Three – four days after it has been fertilised the monula will move from the fallopian tube and will enter the uterus. At about six days the monula will form a hollow cavity which is known as a blastocyst. The blastocyst will burrow itself into the uterus lining this is called implantation.…