Activity 1 c1
- 1. Name: Maricris P. Nebiar Date: November 28, 2020 Instructor: Ms. Odessa V. Balmes Code: MC2-KZb Course: BSN 1B Activity 1: Biochemistry and the Organization of Cells 1. Define the following terms: a. Catalysis: It is the increase in the velocity of a chemical reaction or process produced by the presence of a substance that is not consumed in the net chemical reaction or process; negative catalysis denotes the slowing down or inhibition of a reaction or process by the presence of such a substance. b. Organelle: Any of the organized cytoplasmic structures of distinctive morphology and function present in all eukaryotic cells, including such structures as the nucleus, mitochondria, lysosomes, peroxisomes, Golgi apparatus, and endoplasmic reticulum, as well as chloroplasts in plants and cilia and flagella in protozoa and one of the specialized parts of a protozoan or tissue cell; mitochondria, the Golgi apparatus, nucleus and centrioles, granular and agranular endoplasmic reticulum, vacuoles, microsomes, lysosomes, plasma membrane, and certain fibrils, as well as plastids of plant cells. c. Vacuole: It is a membrane-bound organelle in the cytoplasm of most cells, especially plant cells, containing water and dissolved substances such as salts, sugars, enzymes, and amino acids. And a small extracellular cavity or space within a tissue a clear space in the substance of a cell, sometimes degenerative in character, sometimes surrounding an englobed foreign body and serving as a temporary cell stomach for the digestion of the body. d. Polymer: A substance formed by joining smaller molecules. For example, plastic, acrylic, cellulose acetate, cellulose propionate, nylon, etc. e. Genetic Code: It is the genetic information carried by the specific DNA molecules of the chromosomes; specifically, the system whereby particular combinations of three consecutive nucleotides in a DNA molecule control the insertion of one particular amino acid in equivalent places in a protein
- 2. molecule. The genetic code is almost universal throughout the prokaryotic, plant, and animal kingdoms. There are two known exceptions: In ciliated protozoans, the triplets AGA and AGG are read as termination signals instead of as L-arginine. This is also true of the human mitochondrial code, which, in addition, uses AUA as a code for L-methionine (instead of L- isoleucine) and UGA for L-tryptophan (instead of a termination signal). And is the arrangement of nucleotides in the polynucleotide chain of a chromosome; it governs the transmission of genetic information to proteins, i.e., determines the sequence of amino acids in the polypeptide chain making up each protein synthesized by the cell. Genetic information is coded in DNA by means of four bases: two purines (adenine and guanine) and two pyrimidines (thymine and cystosine). Each adjacent sequence of three bases (a codon) determines the insertion of a specific amino acid. In RNA, uracil replaces thymine. 2. List five (5) differences between prokaryotic and eukaryotic. Prokaryotic Cell Eukaryotic cell Size is 0.1- 5.0 um Size is 5-100 um Nucleus is absent Nucleus is present Membrane-bound nucleus absent. Membrane-bound Nucleus is present. One chromosome is present, but not true chromosome plastids More than one number of chromosomes is present. Unicellular Multicellular Lysosomes and Peroxisomes absent Lysosomes and Peroxisomes present Microtubules absent Microtubules present Endoplasmic reticulum absent Endoplasmic reticulum present Mitochondria absent Mitochondria present Cytoskeleton absent Cytoskeleton present Ribosomes smaller Ribosomes larger Vesicles present Vesicles present Golgi apparatus absent Golgi apparatus present Chloroplasts absent; chlorophyll scattered in the cytoplasm Chloroplasts present in plants Submicroscopic in size Flagella is present and made up of only one fiber Microscopic in size, membrane-bound Cell wall chemically complexed Cell wall is present in plants and fungi and chemically
- 3. simpler Vacuoles absent Vacuoles present Permeability of Nuclear membrane is not present Permeability of Nuclear membrane is selective Sexual reproduction is absent Sexual reproduction is present Endocytosis and exocytosis are absent. Endocytosis and exocytosis occurred It may have pili and fimbriae. Pili and fimbriae are absent Transcription occurs in the cytoplasm Transcription occurs inside the nucleus. Examples: Bacteria and Archaea Examples: Protists, Fungi, Plants, and Animals
- 4. 3. Which organelles contain DNA? It is Nuclei, mitochondria, and chloroplasts all contain DNA. The DNA found in mitochondria and in chloroplasts differs from that found in the nucleus. Which organelles are sites of energy yielding reactions? It is the Mitochondria because it carries out a high percentage of the oxidation (energy-releasing) reactions of the cell. They are the primary sites of ATP synthesis. Which organelles are surrounded by a double membrane? The Nuclei, mitochondria, and chloroplasts are all enclosed by a double membrane. 4. What are the advantages of being eukaryotic? In the nucleus, organelles and the outer wall of the cell, the major structural variations lie. Such variations give rise to unique eukaryote benefits and capacities that prokaryotes do not have. As a consequence, prokaryotes remain single-cell species that are basic. While there are also single-cell eukaryotes, some eukaryotes have made use of these benefits to grow into higher plants and animals. Two benefits are provided to eukaryotes by the inclusion of a nucleus in eukaryotic cells. An extra protective enclosure of the DNA represents the nucleus. Consequently, eukaryotic DNA is less vulnerable to mutations. The nucleus also enables better regulation of reproduction. There are several points in the intricate nucleus-based reproductive processes that can serve as a stop to the other cells in the body to coordinate growth and cell multiplication. Organelles are incorporated into eukaryotic cells and functions are concentrated in their own interior spaces. This suggests that in eukaryotic cells, processes such as energy generation and waste removal are much more effective than in prokaryotes. When mitochondria provide the energy of the cell, based on the position they play in the body, cells may have more or less mitochondria. Without organelles, everything needs to be achieved by the entire prokaryotic cell and the productivity ratio is smaller. In complex eukaryotes, the lack of a cell wall is the benefit of allowing eukaryotic cells to assemble themselves into structures such as lungs, limbs, plant stems, and fruit. Depending on their neighboring cells, these cells work together and separate themselves. Such near encounters can be avoided by a cell wall. While prokaryotic cells in simple structures often clump together, they do not distinguish the way eukaryotic cells do in complex organisms. The capacity to shape advanced, multicellular species is the main structural advantage of eukaryotes over prokaryotes. Prokaryotes do not have the capacity to shape complex structures or populations, while eukaryotes can live as both single-cell and multicellular organisms. 5. Assume that a scientist claims to have discovered mitochondria in bacteria. Is such a claim likely to prove valid? Explain your answer in not more than five sentences. No because Bacteria lack eukaryotes' membrane-binding nuclei; their DNA forms a tangle known as a nucleoid, but there is no membrane across the nucleoid and as in eukaryotes, the DNA is not bound to proteins. Whereas eukaryote DNA is organized into linear parts, bacterial DNA forms loops of chromosomes. Bacteria contain plasmids,
- 5. or short loops of DNA, that can be spread either by sex (yes, sexual bacteria) or viruses from one cell to another. This ability to exchange genes with all humans makes bacteria extremely adaptable; beneficial genes can be transmitted very easily across bacterial species, such as those for antibiotic resistance. It also makes bacteria favored by molecular biologists and genetic engineers; it is easy to introduce new genes into bacteria. And bacteria, as eukaryotes do, do not contain membrane-bound organelles such as mitochondria or chloroplasts. However, photosynthetic bacteria can be filled with closely packed folds of their outer membrane, such as cyanobacteria. This membranes have the benefit of increasing the possible region of the surface on which photosynthesis can take place.