Relebogile Moloko 1155553 Introductory life sciences Assignment 1 Prokaryotes and eukaryotes are two different levels of cells. Prokaryotes are cells that do not have a membrane bound nucleus or organelles sounded by membranes and eukaryotes are cells that have a membrane bound nucleus as well as membrane bound organelle. They have obvious structural differences which result in differences functions and cell efficiency. From my research, I have observed that eukaryotes have structural advantages over prokaryotes. This essay will be discussing the differences in the two cells with reference to the metabolic processes and storage of genetic information.
Both animal and plant cells have some similar organelles such as, the plasma membrane, nucleus, mitochondria, endoplasmic reticulum, ribosomes and Golgi apparatus. Although they have a wide variety of similarities, they also have their differences. Plant cells have a rigid structure that surround the cell membrane called the cell wall, while animal cells do not; the cell wall helps retain the shape of the plant cell.
The functions mainly for the nucleolus are RNA-related, and it was also detected the ability of RNA processing and assembly f ribonucleoproteins (RNPs) Another role of the nucleolus is the ability to maturate, assemble and export RNP particles as signal recognition particle, telomerase RNPs and processing of precursor transfer RNAs and U6 small nuclear RNAs.  An additional role in the regulation of the cell cycle was observed, where it manages the stress responses, telomerase activity, and aging. Sequestering or re-leasing some specific proteins in the nucleolus regulates this function. It was always thought that the main function of the nucleolus was linked with the ribosome biogenesis and exportation of mRNA in yeast and mammalian cells, however in recent studies data it was demonstrated the ability of the nucleolus in plant cells in transcriptional gene silencing, mRNA surveillance, nonsense-mediated decay and mRNA export. Eukaryotic ribosomal RNA genes are organized in large clusters, often involving hundreds or thousands of repeated genes, with each gene encoding one copy of the 18S, 5.8S and 25–28S rRNAs.
The instructions for the order of amino acids are made by the genes in an organisms cell. A process called DNA transcription makes up the sequence of the amino acids and then a specific protein is produced. Each protein structure has a specific function in it. Changing the structure will then change its function since it rearranges everything in the protein structure. Proteins are there for an essential part of the body, since it helps form body tissues, like muscles, organs and is used within many biological processes as well.
It is extremely difficult as we think of it as the biological principal code. But Lennox emphasizes that to think of DNA as a straightforward code that simply gets translated into biological structure is very much an oversimplification. Science is learning that DNA, and its relationship to proteins, is much more interesting and complicated than this. Lennox describes some of the relevant issues. Science is learning about the ability of genes to switch on or off.
If one takes the time to research giraffes and the white rhinoceros they will find that they are unique in their own ways, but share similar characteristics and other features. It starts simply with both organisms having the domain of being a eukaryote, meaning that their cells have a nuclei. Both creatures are part of the Kingdom Animalia, meaning that they are animals which are multicellular and heterotrophic organisms. The giraffe and white rhino are both sorted in the phylum Chordate, this means that they consist of a notochord, dorsally situated central nervous system, and pharyngeal slits at some point at some stage in their development. The class of both giraffes and white rhinos is mammalia, which is the same thing as being a mammal.
Cell Division As a eukaryotic organism grows, cells divide and create new cells based on its DNA. This is called cell division. Cell division is the process when a parent cell divides into two or more daughter cells. Cell division occurs as part of the cell cycle. The two types of cell division processes are mitosis and meiosis.
Lareina Chen Mr. Hayward 9A January 11th, 2017 Genetic Engineering Essay Genetic engineering is a powerful and dangerous technology. Sometimes called genetic modification, genetic engineering is the process of altering the DNA in an organism’s genome. Editing the sequence of nucleotides can sometimes lead to extreme harmful effects on the human race, while on the other hand generates huge benefits for society. While talking about Genetic engineering, it is carried out by CRISPR. CRISPR stands for “clustered regularly interspaced short palindromic repeats.” It can quickly twist most of the genes in any plant or animal.
Some proposed that evidence for Panspermia seems weak, and there is the view of Crick (Crick, 1993) who suggests that the implausibility of the RNA world may imply that life that we know of did not originate on our planet, but instead on a planet where there might have been conditions that were selectively favourable for the evolution of RNA. Implications of this are that it is much less adverse for RNA to have existed on a more favourable planet than existing on Earth at a time which would not have favoured the origin of the RNA world (Crick, 1993). The second hypothesis that I will be evaluating is the Oparin-Haldane hypothesis, a theory put forward separately by biochemists Alexander Oparin and J. B. S.Haldane who both subsequently released independent papers. Their theories stated that life started to appear in the oceans during a time of atmospheric reduction.
Introduction Polyploidy is an inherited condition whereby the organism possesses more than 2 complete sets of chromosomes. It is common amongst plants and some fish and amphibians. Advantages of polyploidy include the fact that they are able to use their genes function in other ways that are not necessarily needed in non-polyploidy organisms which allows them to evolve in many different ways. Another way is by disrupting certain self-incompatibility systems, thereby allowing self-fertilization. However there are disadvantages to it as well, such as being problematic for meiosis and mitosis.