INTRODUCTION To divide, a cell must grow, replicate its genetic material (DNA), and split into two daughter cells. Cells perform these tasks in an organized series of steps that make up the cell cycle. In eukaryotic cells, or cells with a nucleus, the stages of the cell cycle are divided into two major phases: interphase and the mitotic (M) phase. • During interphase, the cell grows and makes a copy of its DNA. • The mitotic (M) phase, divides the cell DNA into two sets and its cytoplasm, forming two new cells.
Meiosis Introduction Meiosis is a special type of cell division in which the number of chromosomes in daughter cells is reduced to half, as compared to the parent cell. It takes place in diploid cells only, in animals at the time of gamete production while in plants when spores are produced .There are two meiotic divisions. The first meiotic division is the reduction division whereas the second meiotic division is just like mitosis . Meiosis I It is divided into many sub divisions: • Prophase I • Metaphase I • Anaphase I • Telophase I • Prophase I This is very prolonged phase , and it is different from the prophase of mitosis because in this chromosomes behave as homologous pairs. Each diploid cell has two chromosomes of each type, oe member from each parent , because of fusion of male and female gametes .Each chromosome has two chromatids, because chromosomes have been replicated during interphase.
The sister chromatids are pulled towards oppsite poles of the cell. (http://andrewhulse.weebly.com/archive-blog---life-in-room-213206209/archives/01-2014) Telophase:the chormatids are now called chormosomes. The nuclear envelope reforms arounds the two sets of chromosomes to form two new nuclei and in each nucleus the nucleolus reforms. The spindle fibres disappear and the chromosomes become uncoiled, elongated and are no longer visible.
5. Describe endocytosis and exocytosis and explain the difference between the two. Exocytosis is where cells expel materials by vesicles. Vesicles is another way that molecules move in and out of a cell. When the vesicle approaches the cell membrane, a section of the vesicle's membrane fuses with the plasma membrane.
This essay will be discussing the differences in the two cells with reference to the metabolic processes and storage of genetic information. The most obvious difference is the nucleus and the lack there of a nucleus. In prokaryotes, there is one long chromosome or circular DNA called the nucleoid. This results in the DNA being much simpler than
The living organisms are classified into different groups by means of their differences and similarities. Two of the major/ most important groups are the prokaryotes (Bacteria and Archaea) and eukaryotes (from plants, animals till malaria parasites and fungi). The difference between them is that eukaryotic cells contain membrane-bound organelles, such as the nucleus, whereas the prokaryotic cells don’t. There is also a difference in their cellular structure due to the lack of chloroplast, cell wall and mitochondria in the prokaryotic cells. Furthermore, the DNA material comes in different forms, the DNA of eukaryotic cells comes in forms of chromosomes while the DNA of the prokaryotic cells comes in forms of plasmids (a circular and double-stranded
3. GROWTH AND CELL DIVISION OF PHYTOPLANKTON Phytoplanktons have diversity and are of both the types prokaryotic and eukaryotic. Cell division is the vital process for regeneration. Prokaryotic forms of phytoplankton which comes under domain bacteria divide by basic process of cell division like binary fission. Eukaryotic phytolanktons which comes under domain eukarya are divide by the process of mitosis.
This paper focuses on the organelle genome of eukaryotes, that is, mitochondrial and chloroplast genome. Mitochondria are found in both animals and plants, whereas chloroplast is found only in plants. It was believed that these two organelles were two different, individual living entities. But these organelles were engulfed by a different
Introduction Mitosis can be defined as a process of nuclear division among eukaryotic cells for which a couple of identical daughter cells are produced when the main parent cell divides. The focus point of mitosis is specifically the equal replication of genetic material within the nucleus that occurs through the function of this elaborate process is to keep a constant number of chromosomes in all somatic cells of the body. Mitosis is part of a bigger phase process known as the cell cycle, which is separated into two parts, mitosis and interphase. Interphase is characterised by the term ‘cell growth’ and holds the significantly largest portion of the cell cycle timeline. Mitosis is further segregated into four main stages known as prophase,
Questions 1-2; Page 376 1a. Review: Describe the two main types of mutations. The two main types of mutations are gene mutations and chromosomal mutations. Gene mutations are mutations that are involved with changes within one or few nucleotides. Chromosomal mutations are involved with the changes in the number or structure of chromosomes, which can change the location of genes on chromosomes as well as change the number of copies of some