GEN BIOLOGY - Types of Plant Tissue PDF

GEN BIOLOGY 2. Lateral Meristems Found in the stem, causing secondary growth (width) ❖ Types of Plant Tissue...

GEN BIOLOGY 2. Lateral Meristems Found in the stem, causing secondary growth (width) ❖ Types of Plant Tissue Increase in diameter Produces new bark on trees 3. Intercalary Meristem Located in between permanent tissues Usually present at the base of the node, inter node and on leaf base Responsible for growth in length of the plant and increasing the size of the internode Results in branch formation and growth Remember: Plant tissues work together to form plant organs, such as roots, stems and leaves. Understanding the structure and Permanent Tissues: function of these tissues is essential for Contain non-dividing cells that was understanding plant biology. derived from meristematic tissues Simple Permanent Tissues – group of Meristematic Tissues (Temporary) cells which are similar in origin; similar Function: Consist of actively dividing in structure and function: cells responsible for plant growth and development 1. Parenchyma: Primary growth occurs in only certain, Most abundant tissue specific regions such as the tips of stems Functions: Packaging, storage, or roots. photosynthesis and gas exchange The cells are roughly spherical to Characteristics: Thin cell walls, rectangular in shape and have thin cell intercellular airspaces, irregularly walls. shaped cells As new cells grow and mature, their characteristics slowly change and they become differentiated. Types: 1. Apical Meristems Found in the tips of the roots and stems, 2. Collenchyma: causing primary growth (lengthening) Functions: Support and mechanical Produces new leaves and flowers strength Responsible for the linear growth of an organ Miks  Characteristics: Thickened cell walls, ❖ Types of Cell Modification elongated cells, often found in young stems and petioles A process that occurs after cell division where the newly formed cells are structurally modified so that they can perform their function efficiently and effectively. Types: 1. Apical Modification – found on the apical 3. Sclerenchyma: surface of the cell. Functions: Structural support and protection Characteristics: thick, lignified cell walls, dead at maturity Types: Sclereids (short, stone-like cells) and fibers (long, thread-like cells) Examples: A. Pseudopods Temporary, irregular lobes formed by amoebas and some other eukaryotic cells. Bulge outward to move the cell in order to engulf the prey. Complex Permanent Tissues: 1. Xylem: Function: Transports water and minerals from roots to rest of plant Characteristics: Think, lignified cell walls, dead at maturity B. Cilia and Flagella Types: Tracheids and vessel elements Cilia are usually short, hair -like Structures that move in waves. 2. Phloem: Flagella are long whip-like structures. Function: Transports food (sugars) from Formed from microtubules. leaves to rest of plant Characteristics: Living cells with sieve tubes and companion cells C. Villi and Microvilli These are finger-like projections that arise from the epithelial layer in some organs. Helps to increase surface area for faster and more efficient adsorption. Microvilli are smaller projections. Miks  Arise from the cell’s surface that also increase surface area allowing faster and more efficient absorption. A. Desmosomes/Hemidesmosomes The anchoring junction on the basal surface of the cell. Rivet-like links between cytoskeleton D. Extra-Cellular Matrix (ECM) and Extracellular matrix components A compound secreted by the cell on its such as the basal lamina that underlie apical surface. epithelia. Cell wall is the extra cellular structure in Primarily composed of keratin, integrins plant cells that distinguishes them from and cadherins. animal cells. Glycoprotein is the main ingredient of Specialized Animal and Plant Cell ECM in animal cells. Specialized Animal Cell: 1. Red Blood Cells – specialized to transport oxygen. 2. Pancreatic Cells – possess large amount of other organelles needed for protein export, including a well-developed golgi apparatus and clusters of storage vacuoles loaded with 2. Lateral Modification – found on the lateral enzymes. surface of the cell. 3. Muscle Cells – the human ability to move I the result of the specialized structure of muscle cells. A. Gap Junction Also known as communicating Specialized Plant Cell: junctions. 1. Guard Cell – monitors the plants’ internal Closable channels that connect the condition, changing their shape according to those conditions. cytoplasm and adjoining animal cells. B. Tight Junction Acts as barriers to regulate the ❖ Cell Cycle movement of water and solutes between epithelial layers. A sequence of events that a cell undergoes Prevents the leakage of the ECF. to grow and divide. C. Adhering Junction Anchors junction on the lateral surface Consists of four phases: of the cell. Similar to the anchoring junction of the A. Interphase: basal surface of the cell. G1 Phase: Cell growth and normal function. 3. Basal Modification – found on the basal S Phase: DNA replication. surface of the cell. G2 Phase: Preparation for cell division. Miks  1. Prophase I: Chromosomes condense, B. M Phase (Mitotic Phase) homologous chromosomes pair up Final stage of the cell cycle, is (synapsis), and crossing over occurs, responsible for cell division. exchanging genetic material. It involves two primary processes: 2. Metaphase I: Homologous chromosome mitosis and cytokinesis. pairs align at the equator. 3. Anaphase I: Homologous chromosomes a.) Mitosis: division of the nucleus, ensuring separate and move to opposite poles. that each daughter cell receives an identical 4. Telophase I and Cytokinesis: Two copy of the genetic material. It consists of haploid daughter cells are formed, each four phases: with a unique combination of 1. Prophase: Chromatin condenses chromosomes. into chromosomes, the nuclear envelope disintegrates, and B. Meiosis II spindle fibers begin to form. 2. Metaphase: Chromosomes align 1. Prophase II: Chromosomes condense, at the cell's equator, attached to and spindle fibers form. spindle fibers. 2. Metaphase II: Chromosomes align at 3. Anaphase: Sister chromatids the equator. separate and move towards 3. Anaphase II: Sister chromatids separate opposite poles of the cell. and move to opposite poles. 4. Telophase: Nuclear envelopes 4. Telophase II and Cytokinesis: Four re-form around the separated haploid daughter cells are formed, each chromosomes, and the with a unique genetic makeup. chromosomes decondense. Key Points: b.) Cytokinesis: Cytoplasmic division, forming two daughter cells. The process differs Crossing Over: This process in between animal and plant cells: Prophase I increases genetic diversity. 1. Animal Cells: A cleavage furrow forms Haploid Gametes: The final products of and contracts, pinching the cell into two. meiosis are haploid cells with half the 2. Plant Cells: A cell plate forms and number of chromosomes as the original expands, eventually dividing the cell diploid cell. into two. Genetic Variation: Meiosis generates genetic diversity, essential for evolution and adaptation. Cell cycle ensures the accurate replication and distribution of genetic material, leading ❖ Mitosis VS Meiosis to the formation of new cells. Comparing Mitosis and Meiosis ❖ Cell Cycle: Meiosis Feature Mitosis Meiosis Cell Type Somatic Cells Germ Cells A specialized cell division process that Purpose Growth and Production of produces haploid gametes (sperm and egg Repair Gametes cells) from diploid cells. Number of 1 2 Divisions It consists of two main stages: Ploidy of Diploid (2n) Diploid (2n) Parent Cell Ploidy of Diploid (2n) Haploid (n) A. Meiosis I Daughter Cells Miks Genetic No genetic Genetic The cell membrane is characterized as a Variation variation variation phospholipid bilayer. Number of 2 4 Daughter Cells 2. Cholesterol Another lipid component of the membranes of animal cells. Key Differences Cholesterol molecules are distributed Mitosis produces genetically identical selectively between the phospholipids in diploid daughter cells for growth and the membrane. repair. Helps prevent the cell membranes Meiosis produces genetically diverse from being rigid by preventing haploid gametes for sexual phospholipids from being packed reproduction. together too tightly. ❖ Structure and Components of Cell 3. Integral Proteins Proteins are prepped all over the bilayer Membrane of lipids. Fluid Mosaic Model Integral proteins also known as intrinsic proteins have one or more segments contained in the phospholipid bilayer. Functions: Channeling or transport of molecules across membrane molecules by channel proteins (passive transport) or carrier proteins (both passive and Seymour Jonathan Singer and Garth L. active transport). Nicolson proposed the fluid mosaic model in 1972. 4. Peripheral Proteins Describes the plasma membrane Can be found to integral membrane structure as a mosaic of components. proteins, or they themselves bind into small portion of the lipid bilayer. Functions of Plasma Membrane As well as transmembrane receptors are also associated with ion channels. 1. Uptake of Substances Most of them are hydrophilic. 2. Cell to cell transfer of materials 3. Elimination of Wastes 5. Carbohydrates: Glycoproteins and 4. Gas Exchange Glycolipids 5. Maintenance of homeostatic surroundings Glycoproteins are linked to a carbohydrate chain they are embedded Components of Cell Membrane in the cell membrane. 1. Phospholipid Glycolipids are found on the surfaces of Phospholipid molecules as a phosphate the cell membrane and have a chain of head group, a glycerol backbone and 2 sugar carbohydrates bound to them. fatty acid tails. The phosphate head is charged, polar, Properties of Cell Membrane: and actively hydrophilic (water-loving). 1. The cell membrane is semi-permeable – The fatty acid tail is uncharged, it allows molecules to enter while others nonpolar, and hydrophobic are not. (water-hating). Permits small molecules either polar (water and carbon dioxide) or Miks  non-polar (oxygen and ethanol) to Types of Solutions: pass through freely. 1. Hypertonic Solution – has a Prevents macromolecules (glucose) higher solute concentration than and ions (potassium and sodium) to a cell, causing water to move out pass through freely. of the cell. Plasmolysis – 2. Has specific trans-membrane proteins to shrinking due to loss of water regulate ion (ion channel) and molecule 2. Isotonic Solution – as the same (transport protein) movement and solute concentration as a cell, flexible to permit change of cell resulting in no net movement of morphology when necessary. water. 3. Hypotonic Solution – has a lower solute concentration than ❖ Transport Mechanisms a cell, causing water to move The transport of substances depends on into the cell. the following: C. Facilitated Diffusion 1. The structure and composition of the To control the entrance and exit of membrane. particular molecules, selective 2. Size of the molecules transport of materials is needed. 3. Movement of the molecules or pressure This process utilizes protein gradient. trans-membrane channels that are 4. Internal and external conditions. specific to certain molecules. Passive Transport Active Transport Heat energy of the cellular environment Requiring the cell to expend its energy provides all of the energy; hence, this is reserves. not energy-costly to the cell. Diffusion, Certain molecules are transported in osmosis and facilitated diffusion are all and out of the cell, independent of examples: concentration. A. Diffusion This process requires the expenditure of energy in the form of ATP (Adenosine Process by which the molecules of a triphosphate). substance spread out from a place where they fewer or absent. A. Endocytosis Moves from a higher concentration The process where large molecules to lower concentration. enter the cell by generalized The direction of greater movement non-selective process. of molecules is called net diffusion Composed of two: would continue until equilibrium is o Phagocytosis (or cell-eating) is a attained. particulate material that engulfs B. Osmosis solid particles that are too large Movement of water molecules to enter the cell while diffusion. o Pinocytosis (or cell drinking) is through a selectively permeable membrane into a solution of higher of liquid material or fluids by the solute concentration that tends to cell. Fat globules and fluids rich equalize the concentration of solute in proteins are among the fluids on the two sides of the membrane taken by the pinocytosis process.. B. Exocytosis Miks  The opposite of endocytosis Reactant and Substrate Large molecules that are manufactured in the cell are released This are molecules with exactly the right through the cell membrane. shape (color which is represented in the The cell expels large molecules such role play) that will bind to the enzyme as proteins and polysaccharides. and react. ❖ Enzymes What are Enzymes? Molecules that enable the chemical reactions to occur in all living things. Biological catalysts. Active Site Speeds up the chemical reactions that A site where the enzymes combines take place inside all cells, but without with the substrate or reactant and being used up in the process. transforms into product. There are many thousands of different types of enzymes, and each one A. Lock-and-Key Model catalyzes a different reaction (different Proposed by Emil Fischer in the year shapes and function because the 1894. sequence and type of amino acids in The active site and substrate are two their structure is different). stable structures that fit perfectly The amino acid sequence determines the without any further modification, just characteristic folding patterns of the like a key fits into a lock. protein's structure, which is essential to If one substrate perfectly binds to its enzyme specificity. active site, the interactions between Protein molecules (made up of amino them will be strongest, resulting in high acids). These amino acids are joined catalytic efficiency. together in a long chain called polypeptide chains, which is folded to produce a unique 3D structure. Cells create enzymes based on instructions carried in the cell’s genes (DNA). B. Induced-Fit Model Proposed by Daniel Koshland in the Why does chemical reaction happen in the year 1954. Cytoplasm? Whereas the active site and substrate Cytoplasm serves as a crucial and don't fit perfectly together; instead, they dynamic setting for a range of cellular both alter their shape to connect. functions and processes. Induced fit says the active site will Encompass metabolism, enzyme change to help to substrate fit. activity, and molecule transport, maintenance of cellular equilibrium, the production of cellular components, and the transmission of signals. Its watery and gel-like consistency creates an optimal environment for the execution of these chemical reactions. Cofactor Miks  The optimum temperature for for an enzyme to speed up the reaction is 37 to 38 degrees Celsius. ❖ PH A measure of the acidity or alkalinity of a Either a coenzyme an organic molecule, solution. such as a vitamin or vitamin-derived A pH below 7 is considered as acidic while molecules or an inorganic metal ion a pH above 7 is basic or alkaline. such as zinc. Each enzyme has an optimum pH range. Many of these cofactors will attach near Changing the pH outside of this range will the substrate binding site to facilitate the slow enzyme activity. binding of the substrate to the enzyme. Extreme pH values can cause enzymes to Cofactors can be classed as “prosthetic denature. groups” or “coenzymes” depending on how tightly they are bound to the enzyme Enzyme Concentration o Coenzymes bind more loosely to Enzymes speed up reactions. the enzyme, and are thus As substrate concentration increases, modified during the enzymatic reaction rate increases until enzymes reaction. become saturated. o While prosthetic groups are Increasing enzyme concentration also more tightly bound to the speeds up the reaction, but only up to a enzyme and are not modified. certain point. Differentiate Apoenzyme and Substrate Concentration Holoenzyme Increasing substrate concentration Apoenzyme are enzymes that does not increases reaction rate until enzymes need cofactors (inactive). saturate. While Holoenzymes needs cofactors Similarly, increasing enzyme (active). concentration also speeds up the reaction, but only to a certain point. Presence of any Inhibitors or Activators A molecule that binds to an enzyme and decreases its activity. Factors Affecting Enzymes: Basically, alter the catalytic action of the enzyme and consequently slow down, ❖ Temperature or in some cases, stop catalysis. Temperature is directly proportional. Inhibitors decreases the activity of an Raising temperature generally speeds enzyme. up the reaction and lowering Competitive inhibitors compete with temperature slows down a reaction. substrates for enzyme binding sites. However, extreme high temperatures Enzyme activators increase enzyme can cause an enzyme to lose its shape activity. (denature) and stop working. Substrate binding to one subunit can sometimes enhance the activity of other subunits. Miks  Enzyme activators bind to enzymes, causing a conformational change that enhances catalytic activity, increasing reaction rate. ❖ Redox Reaction A component of an Enzyme Oxidation-Reduction Reaction Also known as Redox Reaction Oxidation refers to the loss of electrons from a substance. Reduction refers to the gain of electrons by a substance. The two processes occurs with one another. Cellular respiration which is the ultimate source of energy in human beings encompasses a series of redox reactions. So, the food that we eat is transformed into energy by redox reactions only. Biochemical processes: a.) Catabolic – breaks molecules down from larger to smaller. Often oxidative in nature and energy releasing. b.) Anabolism – synthesizing large molecules from smaller ones. Often reductive in nature and require energy input. Miks