GEN BIO (Midterms) PDF

GEN BIO CELL Parts THE MAJOR AND SUB-PARTS CELL Basic and fundamental unit of life possesses a highly organized structure that enables it to carry out its vital functions. CELL THEORY 1. The cell is the fundamenta...

GEN BIO CELL Parts THE MAJOR AND SUB-PARTS CELL Basic and fundamental unit of life possesses a highly organized structure that enables it to carry out its vital functions. CELL THEORY 1. The cell is the fundamental or basic unit of life. 2. All organisms are made up of cells. 3. Cells come from preexisting cells. TYPES OF CELLS consists of both membrane-bound and nonmembrane-bound organelles. Structure and Basic Functions OVERVIEW OF THE REGIONS OF THE CELL works together to maintain cellular homeostasis and perform essential life All the life processes (movement, activities. respiration, sensitivity, growth, excretion, reproduction, and nutrition) Composed of several fundamental components that occur within an organism are supported by the cell. The cell contains different parts, called organelles, which carry out different functions  Plasma membrane or Cell membrane – separates the cytoplasm from external environment. Two Major Division of Cell ✓ It comprises the following: Glycolipids Plasma Membrane, and Protoplasm Glycoproteins (cytoplasm, and nucleus). Phospholipids Cholesterol Membrane proteins Structure Of the Cell Membrane Phospholipids consists of the following: HEAD Region - phosphate group - hydrophilic Cell membrane TAIL Region - two fatty acid chains surrounds the cell and is a selective - hydrophobic barrier between the interior and the exterior. make up the phospholipid bilayer. Primary Roles : regulating the passage 2 Phospholipid Layers of substances, including nutrients and waste materials. Phosphate heads - face the cytoplasm Within it, specialized proteins play a and the cell’s exterior. crucial role in facilitating molecular Fatty acid tails – sandwiched. transport and cellular communication. Bound the cell composed of a phospholipid bilayer embedded with proteins and carbohydrates. Semi-Permeable – means that not everything can enter or pass through it  The cell membrane plays several Microvilli important roles for the continued specialized fingerlike folds existence of the cell. singular: microvillus Semi-permeability allows the cell to mainly increase the surface area of the choose the substances to absorb, cell secrete, or excrete. enable the cell to perform several Substances that are absorbed and functions, depending on the type and excreted by the cell must pass through location of the cell. the cell membrane. found on the surfaces of egg cells and Membrane Proteins (proteins in the white blood cells. phospholipid bilayer) – transport molecules across the cell membrane ✓ allow the entry and exit of molecules that cannot easily pass through the phospholipid bilayer. ✓ Cholesterol helps keep the phospholipid bilayer from becoming stiff, thus providing fluidity. Cytoplasm a gel-like matrix containing water, salts, proteins, and other molecules Transport proteins in the membrane may either occupies the intracellular space be in the form of carrier proteins or channel between the cell membrane and the proteins nucleus. plays a crucial role in biochemical Roles of Membrane Proteins reactions, energy production, and channel proteins – passageway of certain substance transport. molecules Essential for cellular metabolism, it carrier proteins – change conformation to provides structural support to the cell. transport molecules important roles: cell recognition proteins – detect invading 1. Where the molecules first pass through after pathogens entering or before exiting the cell membrane. receptor proteins – binding of molecules to 2. The organelles can also move within and trigger responses around the cytoplasm. It contains the semifluid substance called the cytosol where the different organelles are suspended. Different substances within : electrolytes (substances that produce electrically conducting proteins called tubulins (particularly, solutions), the alpha and beta tubulins). metabolites (substances produced during metabolism), ribonucleic acid (RNA), and synthesized proteins. Intermediate filament – about 10 nm in diameter and is the most stable and the least soluble constituent of the cytoskeleton. ✓ provides tensile strength in the cell. ✓ Helps maintain cell shape ✓ Anchors the nucleus Centrioles The cytoplasm appears to have no form. However, it does have a structure During cell division, the centrioles due to the presence of the come in pairs and are at right angles cytoskeleton. with each other. 3 Major Filaments : They help in the separation and the microfilament movement of the replicated genetic the microtubule, and materials in the cells called the intermediate filament. chromosomes to opposite poles. Cytoskeleton Microfilament – has a diameter of about 7 nanometers (nm) and is mainly composed of a contractile protein called actin. Microtubule – has a diameter of about 25 nm and is composed of globular  Substances that move in and out of the nucleus pass through the envelope's nuclear pores Nucleus serves as the control center of the cell, Nuclear Envelope – boundary of the The information in the chromatin nucleus, composed of the outer and the strands enables the nucleus to control inner nuclear membranes. the activities of the cell. ✓ Inside the nuclear envelope is The DNA in the chromatin strands is the the nucleoplasm. basis for the duplication of new genetic ✓ Within the nucleoplasm are materials. strands of chromatin - a ✓ ensures that new cells formed combination of during cell division will have deoxyribonucleic acid (DNA) genetic materials of their own. and proteins. Also the basis of the information taken by the messenger ribonucleic acid (mRNA) for protein synthesis. ✓ ensures that ribosomes will get the information about specific proteins that need to be produced. primary function : store and safeguard Nucleolus (plural: nucleoli) genetic information, controlling gene a membrane-free organelle found expression and DNA replication. inside the nucleus. In between the membranes is the spherical in shape. perinuclear space. contains fibrils and granules. Fibrils have DNA coding for ribosomal RNA (rRNA). Granules contain rRNA molecules with proteins coming from the cytoplasm Important in creating the ribosomes, which are the sites of protein synthesis. The rRNA produced by the nucleolus, Chromatin strands together with the protein exported from the cytoplasm, produce the ribosomal further condense to form subunit. chromosomes during cell division. The absence of the nucleolus will compromise the process of protein  production because there is none that Endoplasmic Reticulum can produce the ribosome A network of interconnected Protein Synthesis membranes that extends from the nuclear membrane to the cell Building and repairing cellular membrane. structures, regulating biological processes, and expressing specific Plays a fundamental role in the characteristics of each organism transport, processing, and distribution of proteins and lipids within the cell. Ribosomes small, dense structures that help in the assembly of proteins in the cell. come in different forms. found freely in the cytoplasm, attached to the endoplasmic reticulum, or as a polyribosome, a series of ribosomes attached to mRNA. essential organelles for cellular functioning and survival. They synthesize proteins using the genetic information from messenger 2 Main Types : RNA (mRNA), which is crucial for Rough Endoplasmic Reticulum (RER) cellular structure, function, and regulation. studded with ribosomes and is involved in the synthesis and modification of proteins. Smooth Endoplasmic Reticulum (SER) specializes in lipid synthesis, carbohydrate metabolism, and detoxification. Golgi Bodies/Apparatus a cell organelle that helps process and package proteins and lipid molecules, Protein synthesis is necessary for the especially proteins destined to be organism's survival exported from the cell. 1.some proteins serve as enzymes, which help It work closely with the ER. speed up chemical processes in the cell. If enzymes are not produced, the reactions in the body will take a very long time or will not take place at all. 2. Without protein synthesis, membrane proteins will not be produced, thus affecting the transport of materials across the cell.  The substance produced in ER will be Flagella and Cillia transported to the Lumen becoming (Singular: Flagellum, Singular: Cilium) vesicles then process in whether it will Responsible for the locomotion or be recognize or will be exited in the cell. movement of the cell. Due to specialized arrangement of microtubules (Euglena, Paramecium, Sperm cell, Egg Cell) Lysosome It originated in the Endoplasmic Reticulum It serves several functions such as: 1. Digest food 2. Recycle old components of cell 3. Kill invading microorganisms Spherical shape bodies about 0.5- 1.0µm Can be found several hundred in ANIMAL CELL. Cell Wall Also known as the “suicide bag” inside the cell. It is the additional covering of a plant. Located outside the cell membrane composed of CELLULOSE Common functions: 1.Maintain the shape of the plant. 2. Protects the cell. 3. Regulate the cell’s uptake of water. Mitochondrion (plural: Mitochondria) Young plants- PRIMARY CELL WALLS ✓ thin and flexible Double membrane organelle Older plants- SECONDARY CELL WALLS ✓ Outer & Inner membrane ✓ thicker and more rigid About 1000 – 2000 mitochondria Exchange of substances occur through found in a animal liver cell. channels between the cell known as Responsible for ATP production PLASMODESMATA. which powers the cell. BACTERIA’s CELL WALL Support and Movement PEPTIDOGLYCAN, composed of amino Maintaining cellular shape, enabling acids and sugars. cellular movement and division, are ✓ gives structure and protection essential for its functioning and for the cell. survival.  FUNGI’s CELL WALL CHITIN, composed of nitrogen containing polysaccharide. ✓ serves as structural support for the cell. Chloroplast a double membrane organelle which enable the cell to perform photosynthesis. Composed of Different parts; 1. Stroma 2. Grana 3. Thylakoid 4. Lumen Vacuole serves as the temporary storage of substances. Plant cell has more visible and lager size vacuole compare to Animals. Maintain “turgor pressure” Composed of different parts; 1.Tonoplast 2. Cell Sap 3. Central Vacuole