Life is defined as the condition that distinguishes animals and plants from inorganic matter. All living things are called organisms. Organisms have multiple abilities which only living things have including the capacity for growth, reproduction, functional activity, and continual change. These processes are preceded by death. Living things are re-created by the process of cellular reproduction. Through cellular reproduction identical cells to pre-existing cells, as well as cells with a new genetic make-up are created. Reproduction is responsible for the continuity of life.
Reproduction is the ability of an organism to create new individuals. There are two modes of reproduction. These modes include sexual and asexual. In asexual reproduction a new offspring is produced from a single parent. The parent and offspring have the same genes and thus have the same traits. On the contrary, sexual reproduction involves two parents. Each parent produces special cells called gametes which fuse in a process called fertilization to form a zygote. (3) These cells are genetically different to each parent cell. Cellular reproduction consists of two processes: meiosis and mitosis will be discussed in detail later in the essay.
Cells consist of many organelles, each of which plays a vital role in its function. The nucleus, however, is the most vital component of the cell. It is the membrane enclosed area of the cell which contains most of the cell's genetic material, organized as multiple long linear DNA molecules. (1) It is therefore also known as the "control center" of the cell.
DNA is the hereditary material in humans and almost all other organisms. It's full name is deoxyribonucleic acid. It consists of nitrogenous bases, which include ...
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...elope reforms around each chromosome set, the spindle fibres disappear, and the nucleolus reforms as it was in the parent cell. (6) Finally, in telophase a cleavage furrow becomes evident and the cytoplasm of the cell divides in a process called cytokinesis, resulting in two separate and independent but identical diploid daughter cells.
Meiosis occurs in two successive nuclear divisions: meiosis I and meiosis II. Meiosis I reduces the ploidy level from 2n to n (reduction) while Meiosis II divides the remaining set of chromosomes in a mitosis-like process (division). (8)
The continuity of life is based on heritable information in the form of DNA and its transmission from one generation to the next. Without the processes of DNA replication and the division of cells by meiosis and mitosis, life would not continue. There would also be no diversity of life on earth.
11.2) Asexual reproduction involves a single individual / parent who pass duplicates of all its genes to its offspring without the fusion of gametes. Sexual reproduction involves two parents who give rise to offspring that have unique combination of genes inherited from the two parents.
Compare and Contrast Mitosis and Meiosis. Meiosis and mitosis describes the process by which cells divide. either by asexual or sexual reproduction to produce a new organism. Meiosis is a form of cell division that produces gametes in humans.
The process of mitosis can take place in either a haploid (23 chromosomes) or a diploid (46 chromosomes) cell. Before a cell can be ready for a mitotic division it must primarily undergo its interphase stage. Following the interphase stage several other stages come into play. These stages are prophase, prometaphase, metaphase, anaphase, and telophase. During each specific stage certain sequences of events take place that assist to the completion of the division.
Sexual reproduction is that the union of male and feminine gametes to create a fertilised egg or zygote. The ensuing offspring inherit one-half their traits from every parent. Consequently, they 're not genetically similar to either parent or siblings, except within the case of identical twins. As theorised by Mendel, adults are diploid, meaning as 2N, having 2 alleles offered to code for one attribute. The gametes should be haploid, signified by N, containing just one allele in order that once 2 haploid gametes mix, they manufacture a traditional diploid individual. The method where haploid sex cells are created from diploid parents is known as meiosis, and it happens solely within the reproductive organs.
The nucleus contains genetic material that controls all the activities within a cell. A nucleus is made up of D...
This means that all the sperm in males and eggs in females are produced from meiosis. Sperm and egg cells are haploid cells-they contain only one of each type of chromosome. Meiosis actually starts with a diploid cell that undergoes two divisions; the end products are four gametes, all genetically different. Meiosis is known as a reduction division because the daughter cells always contain half the amount of chromosomes as the diploid beginner cell. Chromosomes come in pairs and these pairs are called homologous pairs. Homologous chromosomes mean that both of the chromosomes in the pair have the same gene sequence. Human somatic cells(diploid) contain 46 chromosomes consisting of 23 homologous pairs; therefore, human gametes, which are haploid, have 23 total chromosomes-one from each homologous pair. Just like in mitosis, meiosis undergoes all of the same phases. However, because meiosis involves two divisions, the cell goes through all the phases twice. When referring to the first time the cell undergoes a phase, we say 1, and when referring to the second time, we say 2. For example, when a cell starts prophase the first time in meiosis, we say it is going through prophase 1(P1). Also, there are some differences in the process itself. During P1, homologous chromosomes exchange a section of themselves in what is known as crossing over. This provides a source of genetic variation since part of each chromosome switched places with each other, thus making both chromosomes distinct from the original. Another important difference to know is that in anaphase 1, the doubled chromosomes are not separated into sister chromatids. This doesn’t happen until A2 to ensure that each of the four gametes receives one of each kind of chromosome. There are many key points to understand about meiosis. The first being that cells in meiosis do not go through interphase twice. Interphase is a “one-time” thing; DNA
The nucleus is the CEO of the cell. It controls all cell activity, It regulates movement, reproduction, and eating in the cell. The nucleus contains the of the cell's genetic information. This information is organized as deoxyribonucleic acid molecules, in conjunction with a spread of proteins, to create chromosomes.
Cells are able to grow and reproduce. Cells reproduce by splitting and passing on their genes (hereditary information) to Daughter cells. The nucleus always divides before the rest of the cell divides. Therefore each daughter cell contains their own nucleus. The nucleus controls the cells activities through the genetic material DNA. The cells in a body are all the same except the gametes they were all made from one cell, the Zygote. This is the cell that was formed when two gametes from your parents fused.
Discoveries in DNA, cell biology, evolution, and biotechnology have been among the major achievements in biology over the past 200 years, with accelerated discoveries and insight’s over the last 50 years. Consider the progress we have made in these areas of human knowledge. Present at least three of the discoveries you find to be the most important and describe their significance to society, health, and the culture of modern life. DNA (deoxyribonucleic acid) is a self-replicating molecule or material present in nearly all living organisms as the main constituent in chromosomes. It encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses.
Meiosis is a special type of cell division that occurs during formation of sperm and egg cells and gives them the correct number of chromosomes. Since a sperm and egg unite during fertilization, each must have only half the number of chromosomes other body cells have. Otherwise, the fertilized cell would have too many.
The process of cell division plays a very important role in the everyday life of human beings as well as all living organisms. If we did not have cell division, all living organisms would cease to reproduce and eventually perish because of it. Within cell division, there are some key roles that are known as nuclear division and cytokinesis. There are two types within nuclear division. Those two types being mitosis and meiosis. Mitosis and meiosis play a very important role in the everyday life as well. Mitosis is the asexual reproduction in which two cells divide in two in order to make duplicate cells. The cells have an equal number of chromosomes which will result in diploid cells. Mitosis is genetically identical and occurs in all living
III. Conclusions All organisms in life are made of at least one or more cells. Cells are the basic units to life. Without cells life cannot exist.
Once the sperm fuses with the ovum both chromosomes will pair up and begin the first stages of cell division.
Life according to scientists is “the condition that distinguishes animals and plants from inorganic matter, including the capacity for growth, reproduction, functional activity, and continual change preceding death, also the way of life of a human being or animal.”("Life,”) In order for one to have life, one must have the nine characteristics to be considered a living thing. These nine characteristics are; all living things are made up of cells, living things are able to reproduce, living thing use energy, maintain homeostasis, respond and adapt to the environment, grow and develop, have a life span, evolve over time, and are interdependence. All of the nine characteristics have one thing in common, something that is needed for all living things to use, even if they do not know it. This beautiful thing that all living things should value is photosynthesis. Without photosynthesis there wouldn’t consist humans, animals, insects, and most importantly life!
The main role for cell division if the ability to reproduce. The cell cycle allows multicellular organisms to grow and divide and single-celled organisms to reproduce. From some multicellular organisms, cell division can reproduce an entire organism. It is also primary to the progress of a multicellular organism that commences as a fertilized egg or zygote. These same organisms also benefit from cell division to reconstruct and renew cells that die