Life Scince
Lipids: are organic molecules that are insoluble in wáter, with an oily, waxy or fatty consistency, whose functions are to store energy energy, to participate in muscule contraction, as insulators, and make up part of the cell membranes.there are three kinds of lipids: 1.fatty acids and waxes: that are only made up of carbon, hydrogen, and oxygen.2.´phospholipids: that also contain phosphorus and nitrogen. 3steroids: that are characterized by being made up of fused carbon rings. Fats: which are made up of two or three fatty acids and gycerol, are a rich source of enery, they are found butter and vegetable oil.phosholipids: are made up of a polar head with a phosphale group and two nonpolar fatty acid tails. Steroids: are also lipids that make part of cells; colesterol is the most abundant steroid in animal cells and is used in the production of the bile salls, vitamin D and steid hormondes such as testosterone and estrogen.Proteins:are organic compunds made up of chains of amino acids, they are the must diverse molecules in living things, form the structural part of the body, like keratin, which makes up nails, scales, hoves, hair and feathers.enzymes:are proteins in charge of different chemical reactions.hemoglobins: function is transportation since it is in charge of carrying oxygen to all body cells.(nucleic acids)these are organic molecules that carry the genetic message of the cells, and are made up of subunits called nucleotides in which the sugar of one nucleotide is boned to the phosphate group of another.mucopolysaccharides: these are a type of long chain macro molecules that contain sugars and are found located in body articulations.cuticle: is a protection film that is located in the most external layer of the plants asnd in the one that interacts with the environment.cell biology: concept of cell: The cell is the anatomical and functional unit of living things, since it is capable of surviving independently—either as a unicellular or a multicellular organism—. It meets all of the characteristics of life: reproduction, growth, metabolism, respiration, irritability, etc. All living things, from microscopic bacteria to whales, are made up of cells. Robert Hooke: first person who used the term cell.Anton Van Leevwenhoek:designed tenses of up to 2oo magnification, he descovered animacules.Robert Brown: discovered the nucleus in plant cells.Mathias Shleiden: published that all plants were made uo of cells. Theodor Schawann:published his cell theory for the animal kingdom. Cell theory:states that all living things are made up of one ormore cells , where all metabolic processes take place, new cells arise from the división of preexisting cells, it also recognizes that the cell is the unit of transmission of genetic information.Rudolph Virchow: contributed to the improvement of the cell theopry with his contributions on the origin of the cells.(Types of cells): they are two, prokaryotes and eukaryotic: prokaryotes are unicelular organisms that lack organelles or other internal membrane-bound structures, they dont have a nucleus and the eukaryotic cells are cells that contain a nucleus and organelles, and are enclosed by a plasms membrane.difference between plants and cells: animal cells and plant cells. Both types of cells have organelles such as mitochondria, endomembranous systems, nucleus, cytoskeleton, lysosomes, peroxisomes and plasma membranes; however, we can distinguish some specific structures in each type of cell. Plant cells stand out for having chloroplasts, that allow them to carry out photosynthesis, as well as a cell wall made up of cellulose that provide protection and support; they have huge vacuoles to store water and other nutrients. They also have plastids that serve as storage for carbohydrates such as starch. The vacuoles of animal cells, when they do have them, are not very big. They have centrioles that participate in cell division and they can have cilia, flagella or pseudopods.
.Structure of a cell membrane: All cells have a structure called the cell membrane, which is crucial for the life of the cell, since it establishes the limits between the internal medium, called cytoplasm, and the extracellular medium.different kind of proteins in a cell membrane: Integral proteins are found either totally or partially encompassed by the lipid bilayer, they can completely cross the membrane and transmit signals from the exterior to the interior of the cell, such as transmembrane proteins. The peripheral proteins are found attached to the bilayer or to the integral proteins.Cell process: The cells must carry out the processes of endocytosis and exocytosis when they need to introduce substances that can’t cross the membrane with the help of protein transporters; in endocytosis the cell absorbs substances, and in this process the cell membrane is crucial.In the same way, if the cell needs to get rid of very large substances it carries out exocytosis. organelles that the cell uses to carry out specific vital functions (with a membrane): Nucleus for Protection, access control of DNA. Endoplasmic reticulum (ER) Control and modification of new polypeptide chains; lipid syntesis, other jobs. Golgi apparatus Modification of new polypeptide chains, classification and shipment of proteins and lipids. Vesicles: Transport, storage or digestion of substances in the cell, other functions. MitochondriaATP synthesis from the decomposition of sugars. ChloroplastSugar synthesis in plants and some protists. LysosomeIntracellular digestion. Peroxisome Inactivates toxins. VacuoleStorage.(organelles without a membrane) RibosomesAssembles polypeptide chains. CentrioliAnchors the cytoskeleton. Genetic material: DNA is considered the molecular basis of life, since it is found in all living things. In DNA we find the codes for all the characteristics necessary to generate a new individual; also, it controls all the cellular activities and self-replication. RNA are diverse, since there are different types:messenger RNA, ribosomal RNA and transfer RNA. These are in charge of transcription, and translation of the information stored in DNA to convert it into a protein. genes, and that they determined the differences that were inherited by individuals of the same species. Genes provide the genetic information necessary to make proteins in two steps: transcription and translation. In transcription. karyotype. During mitosis, in one phase of cell division it is possible to observe the chromosomes in the microscope and see how they are arranged. Point mutations can be classified in the following way: Chromosomal mutations: affect a fragment of the chromosome and sometimes the whole chromosome.Deletion mutations: loss of a chromosome fragment; an example of this type of mutation is cri du chat síndrome.Duplication mutations: a segment of a chromosomes is duplicated and can either stay on the same chromosome or be inserted into another one.Inversion mutations:when a chromosome segment changes its orientation within the chromosome.Translocation mutations: a change in position of a segment of the chromosome.