General Biology 1 PDF

GENERAL BIOLOGY 1 Reviewer STEM ᐧ 1st Quarter **Module 1: Cell Structure & Function** **History of the Cell** - - - - - - - - **The Development of Cell Theory** - In 1855 a Prussian (modern day German) physician by the name of **[Rudolf Virchow]** collaborated his ideas w...

GENERAL BIOLOGY 1 Reviewer STEM ᐧ 1st Quarter **Module 1: Cell Structure & Function** **History of the Cell** - - - - - - - - **The Development of Cell Theory** - In 1855 a Prussian (modern day German) physician by the name of **[Rudolf Virchow]** collaborated his ideas with the other two scientists and they developed the **[Cell Theory]**. He concluded that all cells came from previous cells which are the foundation of cell division quoted, Omnis *cellula e cellula* **Cell Theory** \- All livings things are made up of cells \- Cells are the smallest working units of all living things \- All cells come from preexisting cells through cell division **Definition of Cell** A cell is the smallest unit that is capable of performing life functions.  **Cell Parts** **Organelles** **The Plasma Membrane** \- The Lipid bilayer is a hydrophobic barrier to water-soluble substances - selected substances can penetrate cell membranes through transport protein channels. \- Selective transport of ions and water-soluble molecules maintains the specialized internal environment required for cellular life. **Cell Wall** \- Most commonly found in plant cells & bacteria. \- Supports & protects cells. \- *Cell Wall* surrounds the plasma membrane of fungal, plant, and many protist cells. **Nucleus** \- **Control Center of the Cell** **Nuclear Membrane** \- Nuclear Pore Complexes embedded in the nuclear envelope **regulate the transport of proteins and RNA molecules** between the nucleus and cytoplasm. \- Openings allow material to enter and leave nucleus. \- **separate nucleus from the cell.**  **Nucleolus** \- **Forms Ribosomes** **Cytoplasm** \- Gel-like mixture \- Surrounded by cell membrane \- Cointains all the cell organelles **Ribosome** \- Each cell contains thousands \- **Make proteins** \- Found on ribosomes & floating throughout the cell  **The Endomembrane System** \- Eukaryotic cells have an endomembrane system that divides the cell into functional and structural compartments. \- The endomembrane system includes the nuclear envelope, *endoplastic reticulum, Golgi complex, lysosomes, vesicles, mitochondria,* and *plasma membranes* **Endoplasmic Reticulim** \- Moves materials around in cells \- Smooth Cells: lacks ribosomes (synthesize lipids) \- Rough type (pictured): ribosomes embedded in surface \- Extensive interconnected network (reticulum) of membraneous channels and cisternae \- Each cisternae is formed by a single membrane that surrounds an enclosed space (ER lumen) \- **ER** occurs in two forms: **Rough ER** and **Smooth ER** **Rough ER** \- Rough ER has many ribosomes on its outer surface. \- Proteins are delivered to other regions of the Cell (e.g. Golgi Complex) within small vesicles that pinchs off from the ER  **Golgi Bodies** \- The Golgi complex consists of a stack of flattened, membranous sacs (cisternae). \- Protein \'packaging plant\' \- Move materials within the cell \- Move materials out of cell **Lysosome** \- Digestive \'plant\' for proteins, fats, carbohydrate \- Transported undigested material to cell membrane for removal \- Cell breaks down if lysosome explodes \- Lysosomes are found in animal, but not in plants.  **Mitochondria** \- Produces enthrough chemical reactions \-\-- **breaking down fats** & carbohydrates and **releases it** \- **Controls level of water** and other materials in cell \- Recycles and decomposes proteins, fats, and carbohydrates \- "**powerhouse**" of the cell  **Vacuoles** \- Membrane-bound sacs for storage, digestion, and waste removal \- **Stores materials** such as food, sugar, water, and water products \- Contains water solution \- Help plants maintain **Animal Cell: Peroxisomes**  \- **Peroxisomes are vesicles filled with enzymes that break down hydrogen peroxide** to oxygen and water \- This enzymatic activity protects cell from excessive oxidative products made by the cell. **Chloroplast** - - - - -  **Centrioles** - - **Animal Cell: Centrosome**  - - - - - - - **Cytoskeleton** - - - - - - - - -  **PROKARYOTE VS EUKARYOTE** Cells are characterized as either Prokaryotic or Eukaryotic. The main distinction between the two is the **presence of a membrane-bound nucleus**. One of the most common characteristics of a **Prokaryote** is the **absence of a membrane-bound nucleus**. because of this, the **contents of the nucleus is in an area in the bacterial cytoplasm called the [nucleotide]**. All prokaryotes are unicellular and are relatively small than eukaryotes with an average size of \~**1-5 microns**. The Prokaryotic DNA is single and circular in nature. A **Eukaryote** compared to a prokaryote has a **membrane-bound nucleus** that encloses the genetic material. the shape of DNA is linear and has multiple copies inside the nucleus. when it comes to size, Eukaryotes are relatively larger with an average size of \~**10-100 microns**. **Module 2: Cell Types and Modification** **ANIMAL TISSUES** **Tissues** - are a group of cells of the same kind that performs the same function. There are FOUR classifications of animal tissues and are classified according to function. 1. 2. 3. 4. **EPITHELIAL TISSUES** the epithelial tissues provide boundaries for different organs by lining them. aside from protection, the function of epithelial tissues varies from (1) protection, (2) absorption, (3) filtration, (4) excretion, (5) secretion, and (6) sensory reception dependent on the location of the organ it covers. Epithelial tissues can be classified as either: (a) simple; and (b) stratified. it is based on the number of layers of cells with respect to the basement membrane. Epithelial tissues are also classified according to the shape of cells: (A) Squamous cells are flattened and scale-like; (B) Cuboidal cells are boxlike, approximately as tall as they are wide and; (C) Columnar cells (kŏ-lum′nar) are tall and column-shaped.  +-----------------------+-----------------------+-----------------------+ | **Tissue Type** | **Function** | **Location** | +=======================+=======================+=======================+ | Simple Epithelial | | | | Tissues | | | +-----------------------+-----------------------+-----------------------+ | Simple Squamous | absorption, | - - | | Epithelial Tissues | secretion, | | | | | | | | and filtration. | | +-----------------------+-----------------------+-----------------------+ | Simple Cuboidal | secretion | - - | | Epithelial Tissues | | | | | and absorption | | +-----------------------+-----------------------+-----------------------+ | Simple Columnar | absorption and | - - | | Epithelial Tissues | secretion | | +-----------------------+-----------------------+-----------------------+ | Pseudostra-tified | Filtration | - | | Ciliated Columnar | | | | Epithelial Tissues | | | +-----------------------+-----------------------+-----------------------+ | Stratified Epithelial | | | | Tissues | | | +-----------------------+-----------------------+-----------------------+ | Stratified Squamous | Protection | (Keratinized) Skin | | Epithelial Tissues | | | | | | (Non-Keratinized) | | | | Linings of esophagus, | | | | mouth, and vagina | +-----------------------+-----------------------+-----------------------+ | Stratified Cuboidal | Secretion | Glands | | Epithelial Tissues | | | +-----------------------+-----------------------+-----------------------+ | Stratified Columnar | Protection and | Linings of the male | | Epithelial Tissues | secretion | urethra | +-----------------------+-----------------------+-----------------------+ | Transitional | Stretches rapidly | ureter and bladder | | Epithelium | | linings | +-----------------------+-----------------------+-----------------------+ **Type of Muscle** **Movement** **Striations** **Nucleus** **Intercalated Discs** **Location** -------------------- -------------- ---------------- ---------------- ------------------------ ------------------------------- Skeletal Muscle Involuntary Present Multinucleated Absent Attached to the bones Smooth Muscle Voluntary Absent Uninucleate Absent The lining of Visceral Organs Cardiac Muscle Voluntary Present Uninucleate Absent The heart **NERVOUS TISSUES** Nervous tissues are the main component of the nervous system. The main function is to control all bodily activities. There are 2 main types of cells that compose the nervous tissues. Neuron - responsible for responding to stimuli (via processes called dendrites) and transmission of electrical impulses over substantial distance within the body (via processes called axons)  The second cell in the Nervous tissues are **glial cells** that help the neuron to fulfill its functions **CONNECTIVE TISSUES** The main function of connective tissues is to connect one type of tissue to another. Other functions include (1) binding and supporting, (2) protecting, (3) insulating, (4) storing reserve fuel, and (5) transporting substances within the body. There are 3 characteristics of Connective Tissues that sets it apart from other types of tissues: - - - **Kinds of Connective Tissues** Each type of Connective tissue is made from different blast cells or immature cells. The primary blast cell types by connective tissue class are - - - - Other cell types in the extracellular matrix: - - - - **TYPES OF CONNECTIVE TISSUES** 1. - - - - - - - -  2. 3. 4.  **PLANT TISSUES** Plants like other multicellular organisms are composed of organ systems. There are 2 organ systems in the plant organism. The shoot and root system. The Root system\'s main function is for the absorption of materials from the soil and anchorage for support. The Shoot System is responsible for other plant processes like transport, reproduction, and production of food. **Classification of Plant Tissues** 1. - - -  2. - - - - - - -  **CELL MODIFICATIONS** Cell modifications are parts of the cells that arise from the need to cope with and adapt to their environment. these modifications are not limited to eukaryotes but with prokaryotes as well. Let us classify these cell modifications according to their origin. note that these modifications are not present to all cells but to specific cells that will carry-out specific functions 1. 2. 3.  **Module 3: Cell Cycle** **What is the Cell Cycle?** **Cell cycle** - Is the sequence of phases in the life cycle of the cell. It has three parts, the interphase, cell division (mitosis/meiosis), and cytokinesis. **Terminologies:** - - - - - - **300 millions cells are replaced in our bodies every minute** **INTERPHASE** - - 1. 2. 3. 4. 5. 6. - - - - - - - - - - - - **Regulation at Cellular Checkpoints** - - - -  **The G1 Checkpoint** - - - - - - **The G2 Checkpoint** - - - - **The M Checkpoint** - - **Regulator Molecules of the Cell Cycle** **Positive Regulation of the Cell Cycle** - **Cyclins** regulate the cell cycle only when they are tightly bound to Cdks. To be fully active, the Cdk/cyclin complex must also be phosphorylated in specific locations. Like all kinases, Cdks are enzymes (kinases) that phosphorylate other proteins. Phosphorylation activates the protein by changing its shape. The proteins phosphorylated by Cdks are involved in advancing the cell to the next phase. **Negative Regulation of the Cell Cycle** - **Retinoblastoma (Rb), p53, and p21 proteins** - - - - - As a cell is exposed to more stress, higher levels of p53 and p21 accumulate, making it less likely that the cell will move into the S phase. **Module 4: Mitosis** **STAGES OF MITOSIS** The rate of cell division in multicellular organisms depends on the nature of the particular cell as well as the circumstances. If for example your skin is injured, cells at the site of this injury will undergo rapid division. A soon as the cells divide, healing occurs. The cells of the body are called somatic cells. The cells found in your skin, muscles, bones, lungs, heart, and other internal organs; and other parts of your body are examples of somatic cells. They have a diploid number (2N) or complete sets of chromosomes. **Why do cells divide?** 1. -- If cells grow without limit, an "information crisis" would develop -- DNA cannot serve the needs of the increasing size of a cell 2. -- Food and oxygen have to cross the membrane very quickly -- Waste must get out -- If the cell is too large, this occurs too slowly and the cell will die **PROKARYOTIC CELL DIVISION** - **3 main steps:** 1: DNA Replication---DNA is copied, resulting in 2 identical chromosomes 2: Chromosome Segregation---2 chromosomes separate, move towards ends (poles) of cell 3: Cytokinesis - cytoplasm divides, forming 2 cells -- Each new daughter cell is *[genetically identical]* to the parent cell  **EUKARYOTIC CELL DIVISION** - - --Cells grow --DNA replicated --Organelles duplicated --Divide to form daughter cells 2 Main steps: 1: Mitosis (4 steps---Prophase, Metaphase, Anaphase, Telophase) *Nucleus divides* 2: Cytokinesis---Cytoplasm divide, forming 2 cells Each new daughter cell is [genetically identical] to the parent cell. **What is Mitosis?** It is a process that divides the cell nucleus to produce two new nuclei each with a complete set of chromosomes. It is a continuous process that has four phases: Prophase, metaphase, anaphase, and telophase (PMAT). 1. 2. 3. 4. **METAPHASE**  1. 2. 3. **ANAPHASE** 1. 2. 3. 4. **TELOPHASE**  - - - --animals - pinching of the plasma membrane (Formation of cleavage furrow) --plants- elongates and the cell plate forms( future cell wall and cell membrane) **CYTOKINESIS** 1. 2. 3. 4. **Cell Division vs. Nuclear Division** - - **Module 5: Meiosis**  **What is Meiosis?** A division of the nucleus that reduces the chromosome number by half. - - **Meiosis Halves the Chromosome Number** - - - - **Terminologies** - - - - - - **Two Divisions in Meiosis** - - - Note: only one replication occurs **Fertilization Restores Chromosome Number** - **Visual Tour of Meiosis** - - Meiosis is divided into two stages: 1. 2. **MEIOSIS I** **Interphase** - **Prophase I**  1. 2. 3. 4. **Metaphase 1** - **Anaphase 1**  - **Telophase** - - **Meiosis II** **Prophase and Metaphase** **Prophase II** - - **Metaphase II** -  **Anaphase II** - **Telophase II** - - **How Meiosis Introduces Variation in Traits** - - **Crossing Over in Prophase I** - -  **Comparing Mitosis and Meiosis** - - -  **Significance of Meiosis** One of the major roles of meiosis is to increase variation among individuals. The diversity produces within a population is a direct product of meiosis. If meiosis failed to occur this diversity won\'t exist. **Non-disjunction** Non-disjunction is one of the two major occurrences of Meiosis - - -  - - - **Common Non-disjunction Disorders** ▪ Down's Syndrome -- Trisomy 21 ▪ Turner's Syndrome -- Monosomy 23 (X) ▪ Kleinfelter's Syndrome -- Trisomy 23 (XXY) ▪ Edward's Syndrome -- Trisomy 18 *Having too many or too few chromosomes is a bad thing.* **Down Syndrome is caused by having an extra chromosome 21.** - - **Klinefelter's Syndrome occurs when an individual receives two X chromosomes and a Y chromosome.** ▪ The result is an infertile male with varying degrees of feminity.  **Missing *chromosomes* is bad!** **Turner Syndrome occurs when the individual only gets one sex** **chromosome, an X, from their mother.** - **Edwards syndrome, also known as trisomy 18, is a genetic disorder** **caused by the presence of all, or part of the third copy of chromosome 18.** - -