Cell Cycle and Its Checkpoints PDF

TOPIC: CELL CYCLE AND ITS CHECKPOINTS Most Essential Learning Competency Characterize the phases of the cell cycle and their control points. (STEM_BIO 11/12 -Id-f-6) Cell Cycle A process in which a cell grows and divides to create a cop...

TOPIC: CELL CYCLE AND ITS CHECKPOINTS Most Essential Learning Competency Characterize the phases of the cell cycle and their control points. (STEM_BIO 11/12 -Id-f-6) Cell Cycle A process in which a cell grows and divides to create a copy of itself. It represents all phases in the life of a cell Stages of Cell Cycle 1. Interphase the cell grows and replicates its DNA 2. M Phase or Mitotic Phase the cell divides and transfers one copy of its DNA to two identical daughter cells. Interphase The longest phase of the cell cycle. During this phase the cell grows to its maximum size, performs its normal cellular functions, replicates its DNA, and prepares for cell division. This stage is divided into three parts: G1, G2 and S phases. G1 Phase Metabolically active RNA and proteins are synthesized. Cell growth Preparation of chromosomes for replication Duplication of cellular components S Phase DNA replication occurs. The cell makes an identical copy of each of its chromosomes. G2 Phase Cell may continue to grow and undergo normal cellular functions. Cell will start to replicate its organelles in preparation for mitosis. Enzymes and other proteins are synthesized. M Phase 1. Mitosis The process during cell division in which the nucleus of a cell is divided into two nuclei is called mitosis. 2. Cytokinesis The process during cell division in which the cytoplasm divides. Cell Checkpoints Cell checkpoint A checkpoint is a stage in the eukaryotic cell cycle at which the cell examines internal and external cues and "decides" whether or not to move forward with division. o The G1 checkpoint, at the G1 /S transition. o The G2 checkpoint, at the G2 /M transition. General Biology 1 Lecture – Cell Cycle and Its Checkpoints, Cell Division (Mitosis and Meiosis), Application, Disorders, and Diseases. Prepared for Bauan Technical Integrated High School Grade 11 STEM students.  o The spindle checkpoint, at the transition from metaphase to anaphase. G1 checkpoint main decision point for a cell. A cell checks whether internal and external conditions are right for division in terms of size, nutrients, molecular signals, and DNA integrity If a cell doesn’t get the go-ahead cues it needs at the G1 checkpoint, it may leave the cell cycle and enter a resting state called G0 phase. Some cells stay permanently in G0 phase, while others resume dividing if conditions improve. G2 checkpoint Ensures that DNA replication in S phase has been successfully completed. DNA integrity DNA replication If errors or damage are detected, the cell will pause at the G2 checkpoint to allow for repairs. If the checkpoint mechanisms detect problems with the DNA, the cell cycle is halted, and the cell attempts to either complete DNA replication or repair the damaged DNA. If the damage is irreparable, the cell may undergo apoptosis, or programmed cell death. Spindle checkpoint M checkpoint The cell examines whether all the sister chromatids are correctly attached to the spindle microtubules by a kinetochore. If a chromosome is misplaced, the cell will pause mitosis, allowing time for the spindle to capture the stray chromosome. G0 phase Resting phase is a period in the cell cycle in which cells exist in a quiescent state. Viewed as either an extended G1 phase, where the cell is neither dividing nor preparing to divide, or a distinct quiescent stage that occurs outside of the cell cycle. TOPIC: CELL DIVISION: MITOSIS AND MEIOSIS Most Essential Learning Competency Describe the stages of mitosis given 2n=6 (STEM_BIO 11/12 -Id-f-7) Mitotic Phase Mitosis nuclear division Cytokinesis cytoplasmic division Mitosis Mitosis, a process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical daughter cells. It is a fundamental process for the growth, development, and maintenance of multicellular organisms. Stages of Mitosis 1. Prophase The chromatin material shortens and thickens into individual chromosomes which are visible under the light microscope. Each chromosome consists of two strands or chromatids joined by a centromere. Nuclear membrane and nucleolus disintegrate. In animal cells the centrioles separate and move to opposite poles. In plant cells there are no centrioles to move to the poles, so spindle fibers form in the cytoplasm. General Biology 1 Lecture – Cell Cycle and Its Checkpoints, Cell Division (Mitosis and Meiosis), Application, Disorders, and Diseases. Prepared for Bauan Technical Integrated High School Grade 11 STEM students. 2. Metaphase Chromosomes line up on the equator of the cell. The chromosomes appear in a straight line across the middle of the cell. Each chromosome is attached to the spindle fibers by its centromere. 3. Anaphase Chromosomes divide into chromatids. The chromatids are pulled to opposite poles of the cell by the shortening of the spindle fibers. The chromatids are now called daughter chromosomes. 4. Telophase Nuclear membrane reforms around the daughter chromosomes that have gathered at each of the poles. The daughter chromosomes uncoil to form chromatin once again. Cytokinesis Division of cytoplasm In an animal cell the cell membrane constricts. This invagination or in-folding of the cytoplasm divides the cell in two. In a plant cell a cross wall is formed by the cell plate dividing the cytoplasm in two. A human has 46 chromosomes (a set of 23 you inherit from your mother, and a set of 23 from your father). After the genetic material is duplicated and condenses during prophase of mitosis, there are still only 46 chromosomes – however, they exist in a structure that looks like an X shape. For simplicity, let’s try this. 2n=6 During prophase and metaphase During anaphase and telophase As the image shows, there are 6 chromosomes present, During anaphase, we now have a total of 12 but 12 chromatids. chromosomes and 12 chromatids – in short, each chromatid is now a chromosome. Similarly, in humans (2n=46), there are 46 chromosomes present during metaphase, but 92 chromatids. Similarly, in humans, there are 92 chromosomes present and 92 chromatids during anaphase and telophase General Biology 1 Lecture – Cell Cycle and Its Checkpoints, Cell Division (Mitosis and Meiosis), Application, Disorders, and Diseases. Prepared for Bauan Technical Integrated High School Grade 11 STEM students. Meiosis Meiosis is a specialized type of cell division that occurs in eukaryotic cells, particularly in cells that produce gametes (reproductive cells), such sperm and eggs Meiosis I and Meiosis II are the two primary phases of the meiosis process. Terms to Remember 1. Homologous chromosomes Two chromosomes, one of paternal origin, the other of maternal origin that are identical in appearance. 2. Synapsis Synapsis (also called syndesis) is the pairing of two homologous chromosomes that occurs during meiosis. 3. Tetrad Two homologous chromosomes have each already replicated into a pair of sister chromatids. 4. Crossing over The exchange of genetic material between homologous chromosomes that occurs during meiosis and contributes to genetic variability. 5. Chiasma is the point of contact, the physical link, between two (non-sister) chromatids belonging to homologous chromosomes. Stages of Meiosis Meiosis I – reductional division Meiosis II – equational division Interphase I Similar to mitosis interphase. Chromosomes (DNA) replicate in the S phase. Each duplicated chromosome consists of two identical sister chromatids attached at their centromeres. Centriole pairs also replicate. Prophase I Longest and most complex phase (90%). General Biology 1 Lecture – Cell Cycle and Its Checkpoints, Cell Division (Mitosis and Meiosis), Application, Disorders, and Diseases. Prepared for Bauan Technical Integrated High School Grade 11 STEM students.  Chromosomes condense. Has 5 subdivisions: 1. Leptonema/Leptotene Replicated chromosomes have coiled and are already visible. The number of chromosomes present is the same as the number in the diploid cell. Chromosome appears long thread like and made of two sister chromatids. 2. Zygonema / Zygotene Homologue chromosomes begin to pair and twist around each other in a highly specific manner. The pairing is called synapsis. 3. Pachynema / Pachytene Chromosomes become much shorter and thicker. A form of physical exchange between homologues takes place at specific regions. The process of physical exchange of a chromosome region is called crossing-over. 4. Diplonema / Diplotene The two pairs of sister chromatids begin to separate from each other. It is at this point where crossing-over is shown to have taken place. The area of contact between two non-sister chromatids, called chiasma, becomes evident. 5. Diakinesis The four chromatids of each tetrad are even more condensed and the chiasma often terminalizes or move down the chromatids to the ends. This delays the separation of homologous chromosomes. Metaphase I Shortest phase Tetrads align on the equator. Independent assortment occurs – chromosomes separate randomly causing GENETIC RECOMBINATION Anaphase I Homologous chromosomes separate and move towards the poles. Sister chromatids remain attached to their centromeres. Telophase I Each pole now has haploid (1n) set of chromosomes. Cytokinesis occurs and two haploid daughter cells are formed. In Meiosis I the cytokinesis portion may or may not take place in the cells. If cytokinesis occurs, it occurs by cell furrow formation in animal cells. Cytokinesis occurs by cell plate formation in the case of plant cells. The nucleus of each daughter cell formed after cytokinesis has half the number of chromosomes than that of the parental cell. Meiosis II No Interphase II or very short No DNA Replication Meiosis II is similar to mitosis. Prophase II Same as Prophase in mitosis Nucleus & nucleolus disappear. Chromosomes condense. Spindle forms General Biology 1 Lecture – Cell Cycle and Its Checkpoints, Cell Division (Mitosis and Meiosis), Application, Disorders, and Diseases. Prepared for Bauan Technical Integrated High School Grade 11 STEM students. Metaphase II Same as Metaphase in mitosis. Chromosomes move to the center of the equatorial plane. They get attached to spindle fibers centromere. Anaphase II Same as Anaphase in mitosis. Sister chromatids separate. Telophase II Same as Telophase in mitosis. Nuclei and Nucleoli reform, spindle disappears. Cytokinesis occurs. Four haploid daughter cells are produced which is called gametes (eggs and sperm) For simplicity, let’s try this. 2n=6 During prophase 1 and metaphase 1 During anaphase 1 and telophase 1 As the image shows, there are 6 chromosomes present, As you can see, the separation of homologous but 12 chromatids. chromosomes does not change the chromosome number or the chromatid number. There are still 6 Similarly, in humans (2n=46), there are 46 chromosomes chromosomes (3 * 2-daughter cells) and 12 present during metaphase 1, but 92 chromatids. chromatids (6 * 2-daughter cells). Meiosis II During prophase 2 and metaphase 2 During anaphase 2 and telophase 2 During anaphase, we now have a total of 6 As the image shows, there are 3 chromosomes present chromosomes per cell a total of 12 chromosomes and per cell a total of 6 chromosomes and 6 chromatids per 6 chromatids per cell a total of 12 chromatids. cell, a total of 12 chromatids. Similarly, in humans (n=23), Similarly, in humans, there are 46 chromosomes there are 23 chromosomes present during metaphase 1, present and 46 chromatids during anaphase 2 and but 46 chromatids. telophase 2 General Biology 1 Lecture – Cell Cycle and Its Checkpoints, Cell Division (Mitosis and Meiosis), Application, Disorders, and Diseases. Prepared for Bauan Technical Integrated High School Grade 11 STEM students.  TOPIC: Comparison and Application of Mitosis and Meiosis Most Essential Learning Competency Explain the significance or applications of mitosis/meiosis. (STEM_BIO 11/12 -Id-f-9) Comparison and Application of Mitosis and Meiosis Criteria Mitosis Meiosis Type of cell where the process occurs. Somatic cell Sex cell Number of cell divisions 1 2 Number of daughter cells produced. 2 4 Cells produced (Genetically) Identical Not Identical / Different Chromosome number Remains the same Reduced by half Type of Reproduction Asexual Sexual Pairing of Homologs No Yes Crossing over No Yes Discovered by Walther Flemming Oscar Hertwig (1870) (1876) Stages/Phases Prophase Prophase I & II Metaphase Metaphase I & II Anaphase Anaphase I & II Telophase Telophase I & II Function/Applications Cellular reproduction and general Genetic diversity through sexual growth and repair of the body. reproduction. Application of Mitosis Development and growth The number of cells increases by mitosis enabling organisms to grow from a single cell to a complex multicellular organism. Cell replacement Cells are constantly lost and replaced by new ones in the body. In addition, red blood cells live for only four months, and are replaced by mitosis. Replacement of damaged tissue Some organisms use mitosis to replace body parts. For example, starfish replace lost arms by mitosis. Asexual reproduction Some organisms such as the hydra use mitosis to produce genetically identical offspring. The process is known as budding. Mitosis is also the method by which yeast cells multiply. Application of Meiosis It involves disjunction and reduces the chromosome number. General Biology 1 Lecture – Cell Cycle and Its Checkpoints, Cell Division (Mitosis and Meiosis), Application, Disorders, and Diseases. Prepared for Bauan Technical Integrated High School Grade 11 STEM students.  Chromosomal and genomic mutation may occur due to non-disjunction. Recombination of genes occurs and so variations are produced due to crossing over. There is random distribution of paternal and maternal chromosomes into daughter cells. Due to disturbance in disjunction, chromosomal and genomatic mutation take place. Meiosis I induce the cells to form spores or gametes. TOPIC: Disorders and Diseases Most Essential Learning Competency Identify disorders and diseases that result from the malfunction of the cell during the cell cycle. (STEM_BIO 11/12 -Id-f-10) Disorders & Diseases Disease According to a few articles, a disease is a specific label for concepts of illness. Defined as a result of the pathological response of the body to either external or internal factors. Referred to as abnormalities that can cause physical or emotional stress and pain. Disorder Believed to be the disruption of the usual bodily functions. A Disorder is caused because of the presence of disease in the body. Few articles also say that disorder, simply put, means there is something wrong with the body. What happens when a cell doesn‘t stop dividing? Cancer cell – Cancer is a group of diseases characterized by uncontrolled cell division which leads to growth of abnormal tissue. – Cancer begins when a single cell is transformed or converted from a normal cell to a cancer cell. – Cancer cells grow and divide uncontrollably to form a mass of cancer cells called a tumor. – Cancer cells differ from normal cells in a number of ways: Cancer cells don't listen to signals to stop growing. Cancer cells grow new blood vessels. Cancer cells spread around the body. Types of Tumors Benign Tumor – tumors that cannot spread to other tissues and are non-cancerous. Malignant Tumor – tumors that have the ability to spread to other parts of the body. Cancers are named according to the organ or tissue in which they originate: Carcinoma – Carcinomas are the most common type of cancer. They are formed by epithelial cells, which are the cells that cover the inside and outside surfaces of the body. Sarcoma – Sarcomas are cancers that form in bone and soft tissues, including muscle, fat, blood vessels, lymph vessels, and fibrous tissue (such as tendons and ligaments). Leukemia – Cancers that begin in the blood-forming tissue of the bone marrow. These cancers do not form solid tumors. Lymphoma – Lymphoma is cancer that begins in lymphocytes (T cells or B cells). In lymphoma, abnormal lymphocytes build up in lymph nodes and lymph vessels, as well as in other organs of the body. Chromosome Disorders Nondisjunction General Biology 1 Lecture – Cell Cycle and Its Checkpoints, Cell Division (Mitosis and Meiosis), Application, Disorders, and Diseases. Prepared for Bauan Technical Integrated High School Grade 11 STEM students.  – It is the failure of chromosome pairs to separate during either meiosis I or meiosis II, resulting in an abnormal chromosome number. Trisomy 21 Down syndrome 3 copies of chromosome 21 Trisomy 18 Edward Syndrome 3 copies of chromosome 18 Trisomy 13 Patau Syndrome 3 copies of chromosome 13 Turner Syndrome Turner Syndrome has only one sex chromosome an X. Turner syndrome (XO) is a female. Klinefelter Syndrome A male that has two or more X chromosomes in addition to a Y chromosome. References General Biology 1 for Senior High School Budget of Work General Biology 1 for Senior High School Teaching Guide Learning Activity Sheet – Division of Batangas Province https://www.khanacademy.org/science/ap-biology/cell-communication-and-cell-cycle/regulation-of-cell-cycle/a/cell-cycle-checkpoints-article http://www.bioweb.uncc.edu/biol1110/Stages.htm https://ib.bioninja.com.au/higher-level/topic-10-genetics-and-evolu/101-meiosis/chiasmata.html https://socratic.org/questions/what-are-tetrads-are-they-formed-in-mitosis https://ib.bioninja.com.au/higher-level/topic-10-genetics-and-evolu/101-meiosis/crossing-over.html#previous-photo https://byjus.com/question-answer/what-are-the-sub-stages-prophase-1-of-meiosis-1-explain-briefly/ https://www.tutorialspoint.com.cach3.com/cell_cycle_and_cell_division/meiosis_i_prophase_i.asp.html https://teachmephysiology.com/biochemistry/cell-growth-death/meiosis/ https://ib.bioninja.com.au/higher-level/topic-10-genetics-and-evolu/101-meiosis/chiasmata.html https://socratic.org/questions/what-are-tetrads-are-they-formed-in-mitosis https://ib.bioninja.com.au/higher-level/topic-10-genetics-and-evolu/101-meiosis/crossing-over.html#previous-photo https://byjus.com/question-answer/what-are-the-sub-stages-prophase-1-of-meiosis-1-explain-briefly/ https://www.tutorialspoint.com.cach3.com/cell_cycle_and_cell_division/meiosis_i_prophase_i.asp.html https://teachmephysiology.com/biochemistry/cell-growth-death/meiosis/ https://www.credihealth.com/blog/difference-between-disease-and-disorder/ https://www.technologynetworks.com/cancer-research/articles/benign-vs-malignant-tumors-364765 https://bio.libretexts.org/Bookshelves/Human_Biology/Human_Biology_(Wakim_and_Grewal)/07%3A_Cell_Reproduction/7.7%3A_Mitosis_vs._Meiosis_a nd_Disorders https://www.cdc.gov/ncbddd/birthdefects/surveillancemanual/quick-reference-handbook/trisomy-21-down-syndrome.html https://medlineplus.gov/genetics/condition/trisomy-13/ https://www.ssmhealth.com/cardinal-glennon/fetal-care-institute/genetic-syndromes/trisomy-18-%28edwards-syndrome%29 https://medlineplus.gov/genetics/condition/turner-syndrome/#frequency https://medizzy.com/feed/215538 https://www.invitra.com/en/male-sterility-because-of-testicular-failure/symptoms-of-klinefelter-syndrome/ https://medlineplus.gov/genetics/condition/klinefelter-syndrome/ General Biology 1 Lecture – Cell Cycle and Its Checkpoints, Cell Division (Mitosis and Meiosis), Application, Disorders, and Diseases. Prepared for Bauan Technical Integrated High School Grade 11 STEM students.  TOPIC: STRUCTURES AND FUNCTIONS OF BIOLOGICAL MOLECULES - ENZYMES E – S Models Most Essential Learning Competency 1. Lock and Key Model Describe the components of an enzyme. (STEM_BIO11/12-Ii-j-17) – enzyme’s active site complements the substrate precisely. Explain oxidation/reduction reactions. (STEM_BIO11/12-Ii-j-18) – the substrate fits a particular active site like a key fit into a particular lock. Determine how factors such as pH, temperature, and substrate affect enzyme activity. (STEM_BIO11/12-Ii-j-19) – This theory of enzyme-substrate interaction explains how enzymes exhibit specificity for a particular substrate. Enzymes Enzymes are biological molecules that act as catalysts, speeding up chemical reactions in living organisms. They are primarily composed of proteins, although some RNA molecules, known as ribozymes, can also exhibit enzymatic activity. Most enzymes are made up of protein molecules. Proteins are composed of amino acids linked together in specific sequences, and the unique three-dimensional structure of an enzyme is crucial for its catalytic activity. Enzymes are highly specific. o lactose → lactase o starch → amylase https://ib.bioninja.com.au/higher-level/topic-8-metabolism-cell/untitled-6/models-of-action.html o lipid → lipase o protein → protease 2. Induced Fit Model o The Key Components of Enzymes – the enzyme’s active site is not a completely rigid fit for the substrate. – the active site will undergo a conformational change when exposed to a substrate to improve binding. 1. Active Site The active site of an enzyme is a specific region within the protein's three-dimensional structure. It contains amino acid residues that are involved in binding the substrate(s) and catalyzing the chemical reaction. The active site provides a microenvironment that promotes the reaction's efficiency. 2. Substrates Enzymes act upon specific molecules called substrates. Substrates bind to the active site of the enzyme, and this binding initiate and facilitates the chemical reaction that the enzyme catalyzes. Enzymes are highly specific for their substrates. 3. Cofactors A nonprotein part of an enzyme. It can be an ions or organic molecules. https://ib.bioninja.com.au/higher-level/topic-8-metabolism-cell/untitled-6/models-of-action.html Cofactors help enzymes by participating in the reaction directly or by assisting in substrate binding. 4. Holoenzyme A completely active enzyme with all its quality to fit with a substrate and to accelerate a reaction rate. Redox Reaction 5. Apoenzyme The protein part of an enzyme. An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between It is important for enzymatic activity since they are responsible for the specificity of enzymes to their two species. substrates. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion change by gaining or losing an electron. How an Enzyme Works Comprised of two parts, a reduced half and an oxidized half, that always occur together. OIL RIG – Oxidation is Loss – Reduction is Gain Molecules/ions that accepts electrons is called the oxidizing agent. Molecules/ions that donates electrons is called the reducing agent. There is no net change in the number of electrons in a redox reaction. Those given off in the oxidation half reaction are taken up by another species in the reduction half reaction. General Biology 1 General Biology 1 Lecture – CELL TRANSPORT Lecture – CELL TRANSPORT Prepared for Bauan Technical Integrated High School Grade 11 STEM students. Prepared for Bauan Technical Integrated High School Grade 11 STEM students. Rules in Assigning Oxidation Number Factors Affecting the Enzyme Activity 1. The oxidation state of an individual atom is 0. Enzymatic activity is influenced by a variety of factors, and understanding these factors is essential for 2. The total oxidation state of all atoms in a neutral species is 0 and in an ion is equal to the ion charge. controlling and optimizing enzymatic reactions. 3. Group 1 metals have an oxidation state of +1 and Group 2 an oxidation state of +2 4. The oxidation state of fluorine is -1 in compounds. 1. Temperature 5. Hydrogen generally has an oxidation state of +1 in compounds. Enzymes have an optimal temperature at which they function most efficiently. 6. Oxygen generally has an oxidation state of -2 in compounds. Below this temperature, the reaction rate is generally slower due to reduced molecular motion. 7. In binary metal compounds, Group 17 elements have an oxidation state of -1, Group 16 elements of -2, and Group Above the optimal temperature, enzymes can denature, losing their three-dimensional structure and catalytic 15 elements of -3. activity. 8. The sum of the oxidation states is equal to zero for neutral compounds and equal to the charge for polyatomic ion species. 2. pH Enzymes have an optimal pH range at which they are most active. Redox Reaction Changes in pH can alter the ionization states of amino acid residues in the enzyme's active site, affecting substrate binding and catalysis. Extreme pH values can denature enzymes. 3. Enzyme Concentration The rate of an enzymatic reaction is directly proportional to the enzyme concentration, assuming that other factors are not limiting the reaction. More enzymes mean more active sites available for substrate binding. 4. Substrate Concentration Oxidation occurs when an atom’s oxidation state increases during a reaction where -4 to +4 C (carbon) is The rate of an enzymatic reaction often increases as the concentration of the substrate(s) increases. oxidized. However, this relationship is subject to saturation, as the enzyme's active sites become fully occupied, and Reduction occurs when an atom’s oxidation state decreases during a reaction where 0 to -2 O (oxygen) is further increases in substrate concentration do not lead to a significant increase in the reaction rate. reduced. References Learning Activity Sheet – Division of Batangas Province General Biology 1 Teaching Guide https://microtek.ac.in/assets/courses/msc/Holoenzyme,%20apoenzyme,%20coenzyme%20and%20cofactor.pdf https://www.biologyonline.com/dictionary/apoenzyme https://ib.bioninja.com.au/higher-level/topic-8-metabolism-cell/untitled-6/models-of-action.html Oxidation occurs when an atom’s oxidation state increases during a reaction where 0 to +1 Na (sodium) is https://www.sciencefacts.net/enzyme.html oxidized. Reduction occurs when an atom’s oxidation state decreases during a reaction where 0 to -1 Cl (chlorine) is reduced. Oxidation occurs when an atom’s oxidation state increases during a reaction where 0 to +2 Zn (zinc) is oxidized. Reduction occurs when an atom’s oxidation state decreases during a reaction where +2 to 0 Cu (copper) is reduced. General Biology 1 General Biology 1 Lecture – CELL TRANSPORT Lecture – CELL TRANSPORT Prepared for Bauan Technical Integrated High School Grade 11 STEM students. Prepared for Bauan Technical Integrated High School Grade 11 STEM students.  TOPIC: TRANSPORT MECHANISMS 1. Isotonic Solution – The concentration of solutes outside the cell is EQUAL to the concentration of solutes inside the cell. 2. Hypotonic Solution Most Essential Learning Competencies – The concentration of solutes outside the cell is LESS than the concentration solutes inside the cell. Explain transport mechanisms in cells (diffusion osmosis, facilitated transport, active transport). STEM_BIO11/12- Ig-h-13 3. Hypertonic Solution Differentiate exocytosis and endocytosis. STEM_BIO11/12-Ig-h-14 – The concentration of solutes outside the cell is GREATER than the concentration solutes inside the cell. Cell Transport Membrane transport refers to the collection of mechanisms that regulate the passage of solutes such as ions and small molecules through cell/plasma membranes, which are lipid bilayers that contain proteins embedded in them. The regulation of passage through the membrane is due to selective membrane permeability - a characteristic of biological membranes which allows them to separate substances of distinct chemical nature. In other words, they can be permeable to certain substances but not to others. There are two major ways in which molecules or particles can move across a membrane. It is either by passive or active transport. Water goes in both directions. Water moves into the cell. Water moves out of the cell. ISOTONIC HYPOTONIC HYPERTONIC Passive Transport Passive transport occurs when substances cross the plasma membrane without any input of energy from the cell. Facilitated Diffusion Substances are moving from an area where they have a higher concentration to an area where they have a lower – Facilitated diffusion is a passive transport mechanism that allows the movement of specific molecules concentration. across a biological membrane, such as the cell membrane, without the expenditure of energy (ATP). – It relies on the assistance of transport proteins embedded within the membrane to facilitate the Types of Passive Transport movement of substances that cannot pass through the lipid bilayer of the membrane easily. Diffusion Types of Transport Proteins – Diffusion is the random movement of particles of a solute from a region of high concentration to low concentration. It is therefore said to occur down a concentration gradient. 1. Channel Proteins – These proteins form channels or pores within the membrane, allowing ions or small polar molecules to move through them. – Channel proteins are highly selective, permitting only specific ions or molecules to pass. – An example of a channel protein is the aquaporin, which facilitates the movement of water molecules across the membrane. – 2. Carrier Proteins – Carrier proteins, also known as transporter proteins, bind to specific molecules on one side of the membrane and undergo a conformational change to transport the molecule across the membrane to the other side. – This binding and conformational change process is selective and allows for the facilitated diffusion of – The three main factors affecting the rate of diffusion in cells are concentration gradient, temperature, and specific substances. pressure. – Glucose transporters (GLUT proteins) are an example of carrier proteins involved in transporting The higher the concentration, temperature, and pressure, the faster the rate of diffusion. glucose across the cell membrane. Active Transport Osmosis Active transport is a cellular transport process that moves molecules or ions across a biological membrane against – Osmosis is the diffusion of water across a selectively permeable membrane. Water diffuses across a their concentration gradient, meaning from an area of lower concentration to an area of higher concentration. membrane from the region of lower solute concentration to the region of higher solute concentration until Unlike passive transport mechanisms (such as simple diffusion and facilitated diffusion), active transport requires the solute concentration is equal on both sides. the expenditure of energy, usually in the form of adenosine triphosphate (ATP) or, in some cases, the – In biological systems, osmosis is vital to plant and animal cell survival. The ability of a solution to cause a electrochemical gradient created by ATP-driven pumps. cell to gain or lose water is called tonicity. – Tonicity is a measure of the effective osmotic pressure gradient; the water potential of Types of Active Transport two solutions separated by a partially permeable cell membrane. – There are three classifications of tonicity that one solution can have relative to 1. Primary Active Transport another: hypertonic, hypotonic, and isotonic. In primary active transport, energy is directly used to transport molecules or ions against their concentration gradient. This is typically achieved by transmembrane proteins known as pumps. General Biology 1 General Biology 1 Lecture – CELL TRANSPORT Lecture – CELL TRANSPORT Prepared for Bauan Technical Integrated High School Grade 11 STEM students. Prepared for Bauan Technical Integrated High School Grade 11 STEM students. The most well-known example is the sodium-potassium pump (Na+/K+ pump), which actively transports 2. Exocytosis sodium ions (Na+) out of the cell and potassium ions (K+) into the cell. The pump uses energy from the Exocytosis is the reverse process of endocytosis. It involves the release of large molecules or substances hydrolysis of ATP to move these ions against their concentration gradients, maintaining the proper ion from a cell into the extracellular space. This is typically accomplished by merging secretory vesicles balance and electrical potential across the cell membrane. containing the materials with the cell membrane, allowing their contents to be expelled outside the cell. Exocytosis is crucial for the secretion of various substances, such as hormones, neurotransmitters, and digestive enzymes, as well as the incorporation of new membrane components. References: Learning Activity Sheet in General Biology 1 – Division of Batangas Province General Biology 1 Teaching Guide https://lcbiology.webnode.page/unit-2/diffusion-and-osmosis/ https://biology.stackexchange.com/questions/40395/how-do-lipid-soluble-substances-diffuse-through-the-cell-membrane https://gfycat.com/discover/osmosis-gifs https://dc.edu.au/hsc-biology-maintaining-a-balance/ https://socratic.org/questions/how-does-the-sodium-potassium-pump-work https://ib.bioninja.com.au/standard-level/topic-1-cell-biology/14-membrane-transport/facilitated-diffusion.html https://byjus.com/biology/facilitated-diffusion/ 2. Secondary Active Transport (Coupled Transport) https://www.news-medical.net/life-sciences/What-are-Aquaporins.aspx Secondary active transport relies on the energy established by primary active transport (usually through the Na+/K+ pump) to transport other molecules or ions. There are two main types of secondary active https://www.creative-biostructure.com/mempro%E2%84%A2-glucose-transporter-106.htm transport: https://www.news-medical.net/health/Types-of-Ion-Channels-in-the-Body.aspx o Symport (Cotransport): In symport, molecules or ions are transported in the same direction https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/General_Biology_1e_(OpenStax)/2%3A_The_C across the membrane. One molecule is moved against its gradient while the other is moved with ell/5%3A_Structure_and_Function_of_Plasma_Membranes/5.4%3A_Bulk_Transport its gradient. ▪ For example, the sodium-glucose cotransporter (SGLT) uses the energy created by the sodium gradient to transport glucose into the cell against its concentration gradient. o Antiport (Counter transport): In antiport, molecules or ions are transported in opposite directions across the membrane. As one molecule is transported against its gradient into the cell, another molecule is transported out of the cell with its gradient. ▪ The sodium-calcium exchanger (NCX) is an example of an antiport protein that uses the sodium gradient to exchange sodium ions for calcium ions. TOPIC: BULK TRANPORT Bulk Transport Bulk transport, also known as bulk transportation, refers to the process by which large quantities of materials, molecules, or even entire structures are transported into or out of a cell through various cellular mechanisms. Bulk transport plays a vital role in moving macromolecules, organelles, and other large substances within and between cells. Types of Bulk Transport 1. Endocytosis Endocytosis is the process by which a cell takes in large particles or substances from its external environment by enclosing them in a vesicle formed from the cell membrane. There are three primary types of endocytosis: a. Phagocytosis: In phagocytosis, cells engulf solid particles, such as bacteria, cellular debris, or other large particles, by extending pseudopods (temporary projections) to surround and engulf the material. b. Pinocytosis: Pinocytosis, often referred to as "cell drinking," involves the non-selective uptake of small droplets of extracellular fluid containing dissolved solutes. The cell membrane invaginates to form small vesicles that capture these fluid-filled droplets. c. Receptor-Mediated Endocytosis: This is a highly specific form of endocytosis in which specific molecules, usually ligands, bind to receptor proteins on the cell surface. These receptor-ligand complexes are then internalized in clathrin-coated vesicles. Receptor-mediated endocytosis is essential for the uptake of various molecules, including hormones, enzymes, and cholesterol. General Biology 1 General Biology 1 Lecture – CELL TRANSPORT Lecture – CELL TRANSPORT Prepared for Bauan Technical Integrated High School Grade 11 STEM students. Prepared for Bauan Technical Integrated High School Grade 11 STEM students.  TOPIC: STRUCTURAL COMPONENTS OF THE CELL MEMBRANE AND ITS FUNCTION The ‘FLUID’ part represents how some parts of the membrane can move around freely, if they are not attached to other parts of the cell. The ‘MOSAIC’ part illustrates the ‘patchwork’ of proteins that is found in the phospholipid bilayer. Most Essential Learning Competencies The ‘FLUID’ part represents how some parts of the membrane can move around freely, if they are not attached to other Describe the structural components of the cell membrane. (STEM_BIO 11/12 -Ig-h-11) parts of the cell. Relate the structure and composition of the cell membrane to its function. (STEM_BIO 11/12 -Ig-h-12) The ‘MOSAIC’ part illustrates the ‘patchwork’ of proteins that is found in the phospholipid bilayer. STRUCTURAL COMPONENTS OF THE CELL MEMBRANE FUNCTIONS OF PHOSPHOLIPID BILAYER 1. PHOSPHOLIPID BILAYER It is a semi-permeable structure that does not allow materials to pass through the membrane freely, thus protecting the intra and extracellular environments of the cell. Consists of two layers of phospholipids. Each phospholipid has a polar, hydrophilic (water-soluble) head as well as a non-polar, hydrophobic (water-insoluble) tail. FUNCTIONS OF MEMBRANE PROTEINS Junctions – Serve to connect and join two cells together. 2. MEMBRANE PROTEINS Enzymes – Fixing to membranes localizes metabolic pathways. These are proteins found spanning the membrane from the inside of the cell (in the cytoplasm) to the outside of the cell. Transport – Responsible for facilitated diffusion and active transport. Membrane proteins have hydrophilic (polar) and hydrophobic (nonpolar) regions that allow them to fit into the cell Recognition – May function as markers for cellular identification. membrane. Anchorage – Attachment points for cytoskeleton and extracellular matrix. Transduction – Function as receptors for peptide hormones. Types of Membrane Proteins FUNCTIONS OF CHOLESTEROL Integral proteins are permanently attached to the membrane and are typically transmembrane (they span across the bilayer) Immobilize the outer surface of the membrane, reducing fluidity. Peripheral proteins are temporarily attached by non-covalent interactions and associate with one surface of the It makes the membrane less permeable to very small water-soluble molecules that would otherwise freely cross. membrane. It functions to separate phospholipid tails and so prevent crystallization of the membrane. It helps secure peripheral proteins by forming high density lipid rafts capable of anchoring the protein. FUNCTIONS OF GLYCOPROTEINS These proteins are useful for cell-to-cell recognition. FUNCTIONS OF GLYCOLIPIDS Act as recognition sites for specific chemicals and are important in cell-to-cell attachment to form tissues. https://ib.bioninja.com.au/standard-level/topic-1-cell-biology/13-membrane-structure/membrane-proteins.html References 3. CARBOHYDRATES General Biology 1 for Senior High School Budget of Work General Biology 1 for Senior High School Teaching Guide They are found on the outside surface of cells and are bound either to proteins (forming glycoproteins) or to lipids Learning Activity Sheet – Division of Batangas Province https://nigerianscholars.com/tutorials/introducing-the-cell/fluid-mosaic-model-2/ (forming glycolipids). https://ib.bioninja.com.au/standard-level/topic-1-cell-biology/13-membrane-structure/phospholipid-bilayer.html These carbohydrate chains may consist of 2-60 monosaccharide units and can be either straight or branched. https://www.youtube.com/watch?v=Qqsf_UJcfBc 4. CHOLESTEROL Type of lipid composed of four fused carbon rings. Found alongside phospholipids in the core of the membrane. FLUID MOSAIC MODEL S.J. Singer and G.L. Nicolson proposed the Fluid Mosaic Model of the cell membrane in 1972. This model describes the structure of the cell membrane as a fluid structure with various protein and carbohydrate components diffusing freely across the membrane. General Biology 1 General Biology 1 Lecture – STRUCTURAL COMPONENTS OF THE CELL MEMBRANE AND ITS FUNCTION Lecture – STRUCTURAL COMPONENTS OF THE CELL MEMBRANE AND ITS FUNCTION Prepared for Bauan Technical Integrated High School Grade 11 STEM students. Prepared for Bauan Technical Integrated High School Grade 11 STEM students. K to 12 BASIC EDUCATION CURRICULUM K to 12 BASIC EDUCATION CURRICULUM SENIOR HIGH SCHOOL SENIOR HIGH SCHOOL Grade: 12 Semester: 1 Grade: 12 Semester: 1 Specialized Subject Title: Biology No. of Hours: 80 hours Specialized Subject Title: Biology No. of Hours: 80 hours BIOLOGY In 1839, Theodor Schwann concluded  Most cell membranes contain protein  Digestion of macromolecules; recycling that all animals are made up of cells. molecules and carbohydrate molecules or worn out organelles  Study of living things In 1855, Rudolf Virchow proposed that  Separates cell from external 6. VACUOLES Levels of Organization all cells come from existing cells. He published environment; controls passage of organic Atoms Molecules Cells Tissues Organelles Organ  Sac like structure that often store that all cells come from cells “omnis cellula e molecules, ions, water, oxygen and wastes into cellula” and out of the cell. materials such as water, salts, proteins and Organ System Organism Population Community carbohydrates Francisco Redi in his experiment coined 2. CELL WALL Ecosystem Biosphere  For storage and transport; digestive the maxim “omne vivum ex ovo” or every living  Cell walls are multilayered function in plant cells Characteristics of Living Things things comes from a living thing. 1. Growth Development 4. Metabolism  Cell wall has cell junction called plasmo- In 1931, Janet Plowe demonstrated that desma 7. GOLGI BODIES 2. Reproduction 5. Adaptability 3. Movement 6. Homeostasis the cell membrane is a physical structure, not  For protection, structural support and  Consists of flattened sacs that are not an interface between two liquids maintenance of cell shape interconnected Development of Cell Theory In 1970, Lynn Margulis proposed the 3. CYTOPLASM  It finishes, sorts and ships cell products  In 1665, Robert Hooke publishes his book Micrographia, theory that certain organelles, tiny structures which contains his drawings of section of cork as seen through within some cells, were once free-living cells  is the material within a living cell,  Modifies, sorts, tags, packages and one of the first microscopes. themselves. She is an American evolutionary excluding the cell nucleus distributes lipids and proteins  In 1674, Anton Van Leeuwenhoek observed tiny living theorist and biologist was the primary modern  Provides structure to cell; site of many metabolic reactions; medium in which 8. CHLOROPLAST organisms in drops of pond water through his simple proponent for the significance of symbiosis in microscopes. organelles are found evolution or endosymbiosis theory  Use energy from sunlight to make  Anton Van Leeuwenhoek a Dutch Businessman became 4. MITOCHONDRIA energy rich food molecules in a process known CELL STRUCTURE AND FUNCTION one of the first people to use microscope to study nature. as photosynthesis Using only a single powerful lens, he crafted instruments that  Convert energy from one chemical form could produce magnified images of very small objects. He was to another 9. ROUGH ENDOPLASMIC RETICULUM the first person to see tiny living organism in a drop of water.  It is enclosed by two membranes  Network of interconnected flattened  Leeuwenhoek found motile objects on October 9, 1676 sacs and he states that motility is the quality of life, therefore,  It is composed of two compartments, these were living organisms.  the inter membrane space and the inner  Makes more membrane  1683 Leeuwenhoek discovers bacteria. He had made his membrane observation of single- celled organism that he name  Involved in the synthesis of proteins animalcules like protozoa and bacteria.  ATP production or cellular respiration 10. SMOOTH ENDOPLASMIC RETICULUM  In 1838, Matthias Schleiden concluded that all plants are 5. LYSOSOMES made up of cells. Mathias Schleiden is a German Botanist who  Network of interconnected tubules that study plant structure under the microscope. He stated that all  Produced by rough ER and golgi lack ribosomes parts of the plant organism are composed of cells. He also apparatus  Synthesize lipids, including fatty recognized the importance of cell nucleus and sensed its  connection to cell division. He concluded that all plant parts  Derived from two Greek words meaning acids,phospholipids and steroids are made of cells. 1. CELL MEMBRANE “breakdown body”  Double layered called lipid bilayer  Digest cell’s food and wastes 1 2  K to 12 BASIC EDUCATION CURRICULUM K to 12 BASIC EDUCATION CURRICULUM SENIOR HIGH SCHOOL SENIOR HIGH SCHOOL Grade: 12 Semester: 1 Grade: 12 Semester: 1 Specialized Subject Title: Biology No. of Hours: 80 hours Specialized Subject Title: Biology No. of Hours: 80 hours 11. RIBOSOMES  Unspecified role in cell division in animal were single-celled organisms. They arose cells; organizing center of microtubules in about 1 billion years later than the  Ribosomes produced proteins following animal cells earliest prokaryotes. coded instructions that comes from the 18. FLAGELLA nucleus TABLE OF COMPARISON BETWEEN A  Cellular locomotion PROKARYOTE AND EUKARYOTE 12. NUCLEUS 19. CILIA BASIS OF PROKARYOTE EUKARYOTE  Cell’s genetic control center  Cellular locomotion, movement of COMPARISON particles along extracellular surface of plasma Size Smaller Larger  Cell’s hereditary blueprint membrane, and filtration Structure Less complex More complex  Cell organelle that houses DNA and Presence of No nucleus Has nucleus directs synthesis of ribosomes and proteins nucleus 13. NUCLEOLUS PROKARYOTE VS. EUKARYOTE Presence of Lacks Contains organelles membrane membrane  Consist parts of chromatin DNA bound bound organelles organelles combined with RNA and proteins Number of Unicellular Unicellular  It is where the components of ribosomes cells in an organism and organism multicellular are made organism 14. CHROMATIN Classification Eubacteria and Protista, PROKARYOTIC CELL Archaebacteria Fungi, BACTERIAL CELL  Granular material consist of DNA bound Animalia,  A prokaryote is an organism made of a Plantae to protein single prokaryotic cell. The earliest prokaryotes 15. CYTOSKELETON may have arisen more than 2.5 billion years ago Similarities of Prokaryote and Eukaryote  A network of protein filament that helps MAIN FEATURES OF PROKARYOTIC CELL  Presence of DNA the cell maintain its shape They are very small cells with a simple  Presence of Ribosomes structure  It is also involved in many forms of cell  Presence of Cytoplasm Their DNA is not enclosed in a movement membrane inside the cell TABLE OF COMPARISON BETWEEN AN ANIMAL  Maintains cells’ shape, secure organelles Some prokaryotes are enclosed by an CELL AND A PLANT CELL on specific positions, allows cytoplasm and additional layer called the capsule vesicles to move within the cell, and enables It lacks nucleus BASIS OF ANIMAL CELL PLANT CELL unicellular organisms to move independently No membrane bound organelles COMPARISO It contains one or more flagella for N 16. PEROXISOMES movement Size Comparativel Usually larger y smaller  Oxidizes and breaks down fatty acids and EUKARYOTIC CELL Shape Round Rectangular amino acids and detoxifies poisons (Irregular) (Fixed) Eukaryotes are organisms made of one Cell Wall Enclosed by Enclosed by a 17. CENTROSOMES or more eukaryotic cells. The earliest th rigid cell wall eukaryotes, like the first prokaryotes, 3 4 K to 12 BASIC EDUCATION CURRICULUM K to 12 BASIC EDUCATION CURRICULUM SENIOR HIGH SCHOOL SENIOR HIGH SCHOOL Grade: 12 Semester: 1 Grade: 12 Semester: 1 Specialized Subject Title: Biology No. of Hours: 80 hours Specialized Subject Title: Biology No. of Hours: 80 hours in, flexible  For exchange of material through  Lines the labia majora  Mucous membranes of reproductive and plasma diffusion urinary system membrane  Lines the air sacs of the lungs h. Pseudo- stratified columnar b. Fibrous Connective Tissue  Lines the glomerulus of kidney  Single layer of cells, may look stacked  Made up of collagenous fibers found in Chloroplast Absent Present  Capillaries, blood vessels because of varying height tendons and ligaments Vacuoles Often possess Contains many small large central b. Simple Cuboidal Epithelium  Usually with cilia  Consists of collagen known to provide vacuoles vacuole  Shape like dice  Lines the respiratory tract strength and stability Lysosomes Lysosomes Lysosomes  Single layers of cells with relatively large  Ligaments and tendons are always are rare 2. Connective tissues vary widely in their form and amount of cytoplasm present  For secretion function, but they are all characterized by the presence c. Cartilage Plasmodesma Tight Tight  Lines the thyroid follicles of extracellular matrix. The extracellular matrix is ta junctions and junctions and nonliving material composed of protein fibers and  Firm matrix with abundant collagen  Lines the ovaries fibers desmosomes desmosomes ground substance. The protein fibers are composed of are present. are absent.  Lines the testis  Provide structural support and collagen or elastin. The number and types of fibers cushioning properties Plasmodesma Plasmodesma  Proximal tubule of the kidney differs from the various types of connective tissue.  Found in rib cage, nose, trachea and end ta absent ta present Reserved Reserved Reserved The ground substance fills the spaces of long bones c. Simple Cuboidal Ciliated food food is in the food is in the between the cells and the fibers. It contains d. Bone  Lines the terminal bronchioles and form of form of interstitial fluid (tissue  Bone tissue forms the skeletal system respiratory bronchioles  Provide structural support, protection glycogen starch fluid) and large polysaccharide molecules. and mineral storage d. Simple Columnar Epithelium The consistency of the ground substance can  Found in arms, shoulder,hips,legs  Brick-shaped cells vary from liquid to gel-­­like to a solid. e. Blood ANIMAL TISSUES  For secretion and active absorption  Made up of plasma, contains water, salts 1. Epithelial tissues line body surfaces and cavities, as and dissolved proteins  Lines the stomach, small intestine, large well as form glands. The cells of the tissue are closely  WBC, RBC and platelets intestine and rectum connected to each other via cellular junctions and  Lines the gall bladder 3. Muscle tissues are composed of long cells because epithelium is found on the edges of organs, it has two distinct surfaces. The apical surface is exposed  Lines the cervix called muscle fibers that allow the body to move to the body cavity or exterior, while the basal surface is  Lines the ejaculatory duct voluntary or involuntary. Muscle tissue is adjacent to the underlying tissue. specialized for contraction. The cells are e. Simple Columnar Ciliated elongated, and are also known as muscle fibers.