General Biology 1- Quarter 1 for High School, Senior High School, Study notes of Biology

Download General Biology 1- Quarter 1 for High School, Senior High School and more Study notes Biology in PDF only on Docsity! DEPARTMEN / EDUCATION GENERAL BIOLOGY 1 QUARTER 1 - MODULE 1 CELL THEORY AND CELL STRUCTURES GENERAL BIOLOGY 1 —- GRADE 11 QUARTER 1 — MODULE 1: CELL THEORY AND CELL STRUCTURES Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit. Such agency or office may, among other things, impose as a condition the payment of royalties. Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this book are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them. Regional Director: Gilbert T. Sadsad Assistant Regional Director: Jessie L. Amin Development Team of the Module Writers: Sarah Kimberly F. Lamadrid Editors: EXCELSA F. BUAN Reviewers: DR. NOEL V. IBIS, EPS / DARCY GUY Y. MANEBO, EPS Illustrator: Sarah Kimberly F. Lamadrid Layout Artist: Sarah Kimberly F. Lamadrid oe ey, s ;, Regional Center Site, Rawis, Legazpi City 4500 — 2 (© ont a7 tame (@) redonbadepedgov.ph RECAONY BICOL The cells vary considerably, in shapes and sizes (Fig.4.1). Nerve cells of animals have long extensions. They can be several centimeter in length. Muscle cells are elongated in shape. Egg of the ostrich is the largest cell (75 mm). Some plant cells have thick walls. There is also wide variation in the number of cells in different organisms. ee jr 2. CELL STRUCTURE AND FUNCTIONS The study of cellular ultrastructure (cell anatomy) is always accompanied by the study of its functions and processes cell physiology), which are mediated by different organelles at the cellular level. Each organelle plays a specific role, which eventually contributes importantly to the general functioning of the cell. The cell structure comprises individual components with specific functions essential to carry out life's processes. These components include- cell wall, cell membrane, cytoplasm, nucleus, and cell organelles. a. Cell Membrane / Plasma Membrane The cell membrane supports and protects the cell. It controls the movement of substances in and out of the cells. It separates the cell from the external environment. The cell membrane is present in all the cells. The cell membrane is the outer covering of a cell within which all other organelles, such as the cytoplasm and nucleus, are enclosed. It is also referred to as the plasma membrane. By structure, it is a porous membrane (with pores) which permit the movement of selective substances in and out of the cell. Besides this, the cell membrane also protects the cellular component from damage and leakage. It forms the wall-like structure between two cells as well as between the cell and its surroundings. Plants are immobile, so their cell structures are well-adapted to protect from them from external factors. The cell wall helps to reinforce this function. ar ae LE Emerior Cligosaccharide Jeon front eon Intearat Coa Cellulose en Membrane| CELL MEMBRANE Source: Vikasana-Bridge Course 2012 Figure 1. Structure of Cell wall and Cell membrane Structure — Outermost non-living layer present in all plant cells. Secreted by the cell itself. — In most plants, it is chiefly made up of cellulose but may also contain other chemical substances such as pectin and lignin. — The substance constituting the cell wall is not simply homogeneous, but it consists of fine threads or fibers called microfibrils. — It may be thin (1 micron) and transparent as in the cells of onion peel. In some cases, it is very thick as in the cells of wood. Functions — The cell wall protects the delicate inner parts of the cell. — Being rigid, it gives shape to the cell. — As it is rigid, it does not allow distension of the cell, thus leading to turgidity of the cell that is useful in many ways. — It freely allows the passage of water and other chemicals into and out of the cells. — There are breaks in the primary wall of the adjacent cells through which cytoplasm of one cell remains connected with the other. These cytoplasmic strands which connect one cell to the other one are known as plasmodesmata. — Walls of two adjacent cells are firmly joined by a cementing material called middle lamella made of calcium pectinate. Intext Questions 1: Encircle the letter of the correct answer. oO . A suitable term for the various components of cells is Yo . tissue b. chromosomes c. cell organelles d. genes by » . The thin, flexible barrier around a cell is called the a. cell membrane b. cell wall c. cell envelope d. cytoplasm 3. Which of the following is not found on the cell membrane? a. protein channel b. carbohydrates c. phospholipid d. ribosome b. Cell Wall The cell wall is the most prominent part of the plant's cell structure. It is made up of cellulose, hemicellulose and pectin. The cell wall is present exclusively in plant cells. It protects the plasma membrane and other cellular components. The cell wall is also the outermost layer of plant cells. It is a rigid and stiff structure surrounding the cell membrane. It provides shape and support to the cells and protects them from mechanical shocks and injuries. It is Nonliving layer found in plants, fungi, & bacteria. Made of cellulose in plants, made of peptidoglycan in bacteria and made of chitin in Fungi c. Cytoplasm The cytoplasm is a thick, clear, jelly-like substance present inside the cell membrane. Most of the chemical reactions within a cell take place in this cytoplasm. The cell organelles such as endoplasmic reticulum, vacuoles, mitochondria, ribosomes, are suspended in this cytoplasm. The cytoplasm contains many cell organelles of which we shall learn about: 1. those that trap and release energy e.g. mitochondria and chloroplasts; 2. those that are secretory or involved in synthesis and transport e.g. Golgi, ribosomes and endoplasmic reticulum 3. the organelles for motility - cilia and flagella 4. the suicidal bags i.e. lysosomes 5. the nucleus which controls all activities of the cell, and carries the hereditary material Q. Intext Questions 2: Encircle the letter of the correct answer. . The cell wall of a plant is made up of a. chitin b. cellulose —_c. peptidoglycan 2. Chitinous cell wall is present in . a. Plants b. Bacteria cc. Fungi 3. Which of the following statements are not true regarding cell wall? a. Cell wall is semi-permeable. b. Cell wall provides mechanical support to the cell. c. The cell wall is also the outermost layer of plant cells. 4. Which of the following cell part is not suspended in the cytoplasm? a. nucleus b. endoplasmic reticulum c. cell membrane 5. It is the part of the cell where most of the chemical reactions within a cell take place. a. nucleus b. cytoplasm cc. ribosome d. Nucleus The nucleus contains the hereditary material of the cell, the DNA. It sends signals to the cells to grow, mature, divide and die. The nucleus is surrounded by the nuclear envelope that separates the DNA from the rest of the cell. The nucleus,protects the DNA and is an integral component of a plant's cell structure. It controls the activities of the cell. Usually the largest organelle. Nucleolus The nucleolus is the site of ribosome synthesis. Also, it is involved in controlling cellular activities and cellular reproduction. Nuclear membrane plasmic Endoj Reticulum The nuclear membrane protects the nucleus by forming a boundary between the nucleus and other cell organelles. Also called as the nuclear Figure 1 envelope. It contains nuclear pores for Figure 2. Structure of the Nucleus and its parts materials to enter & leave nucleus and Source: Vikasana-Bridge course 2012 connected to the rough ER. Q. Intext Questions 3: Write your answer on the space provided. 1. Why cannot the cell survive without the nucleus? 2. What is the function of the nucleolus in the cell? 3. . Given below is a list of functions, relate them to their respective organelles: (a) synthesis of some enzymes (b) synthesis of steroids (c) Intracellular transport (d) Synthesis of proteins 2. Mention any two advantages of the extensive network of endoplasmic reticulum. (i) (ii) 3. What are the three places where ribosomes occur in a cell? 5. Name the membrane system that connects the nuclear membrane with the cell membrane? h. Mitochondria The mitochondrion is called “the powerhouse of the cell.” It is called so because it produces ATP - the cell's energy currency. This organelle is present in eukaryotes but not in prokaryotes. Bacteria can produce ATP with the use of their plasma membrane. Mitochondrion also contains its DNA and able to synthesize few proteins. Aside from the said function, it is also responsible for fatty acid oxidation (Campbell and Farell, 2008). Structure: (a) Wall made up of double membrane, (b) The inner membrane is folded inside to form projections called ‘cristae’ which project into the inner compartment called the ‘matrix’. Appear as tiny thread like structures under light microscope. Approximately 0.5 1.00 ym (micrometer). Number usually a few hundred to a few thousand per cell (smallest number is just one as in an alga, Micromonas. outer membrane /inner membrane ©1956 Encyclopaedia Britannica, Ino Figure 6. Structure of a Mitochondrion Source: Encyclopedia Britannica, Inc. i. Chloroplast Chloroplast, an organelle found only in plants and photosynthetic algae, is the site of photosynthesis. It contains grana (plural of granum), membranous bodies found in the chlorophyll that is mainly responsible for photon processing. The size of chloroplast ranges from 5 — 10 micrometers. It is found in all green plant cells in the cytoplasm. Number 1 to 1008 (how so definite) Shape: Usually disc-shaped or laminate as in Three-dimensional Model of most plants around you. In some ribbon - shaped as Chloroplast Membranes in an alga Spirogyra or cup-shaped as in another alga Pole recat Chlamydomonas. Inner membrane Plastids Plastids are found only in a plant cell. These may be colourless or coloured. Based on this fact, there are three types of plastids. " alae Granum Stroma (stack of {aqueous space) (i) Leucoplast - white or colourless “hois) ee 2 Figure 7. 3D Structure of the Chloroplast ti Chaeeacks OTe OS Source: The McGrawhill Companies Inc. i joroplast — green Chloroplast versus Mitochondria Can you now visualize how these two organelles are opposite to each other, one traps the solar energy locking it in a complex molecule (by photosynthesis), the other releases the energy by breaking the complex molecule (by respiration). Similarities between mitochondria and chloroplast: both contain their own DNA (the genetic material) as well as their own RNA (for protein synthesis). Thus, they can self- duplicate to produce more of their own kind without the help of nucleus. Thought the chloroplasts and mitochondria contain their own DNA the hereditary molecule and also their own ribosomes, they are termed as semi-autonomous only because they are incapable of independent existence outside the cytoplasm for a long time. Since most of their proteins are synthesized with the help of the nuclear DNA. Q. Intext Questions 4: Write your answer on the space provided. 1. Name the chemical which provides energy trapped in its bonds to the cell. 2. Which part of the chloroplasts is the site of light reaction? 3.Name the sac like—-structure which form the grana? 4. Why is mitochondrion called the “power house” of the cell? 5. Which organelle contains enzymes for cellular respiration? 6. State two similarities between mitochondria and chloroplasts j. THE MICROBODIES (TINY BUT IMPORTANT) j.1 Lysosomes Lysosomes are membrane-bound organelles that contain hydrolytic enzymes exemplified by hydrolase. It protects the cell by engulfing the foreign bodies entering the cell and helps in cell renewal. Therefore, it is known as the cell's suicide bags. The main features of lysosomes are as follows: Membranous sacs budded off from Golgi body. May be in hundreds in a single cell. Contain several enzymes (about 40 in number) Materials to be acted upon by enzymes enter the lysosomes Lysosomes are called “suicidal bags” as enzymes contained in them can digest the cell's own material when damaged or dead. gkoN> Importance of intracellular digestion by the lysosomes: (i) help in nutrition of the cell by digesting food, as they are rich in various hydrolysing enzymes which enable them to digest almost all major chemical constituents of the living cell. (ii) Help in defence by digesting germs, as in white blood cells. (iii) Help in cleaning up the cell by digesting damaged material of the cell. (iv) Provide energy during cell starvation by digestion of the own parts of the cells (autophagic, auto : self; phagos: eat up). (v) Help sperm cells in entering the egg by breaking through (digesting) the egg membrane. (vi) In plant cells, mature xylem cells lose all cellular contents by lysosome activity. (vil) | When cells are old, diseased or injured, lysosomes attack their cell organelles and digest them. In other words lysosomes are autophagic, i.e. self devouring. j.-2 Peroxisomes It contains various enzymes that can be catalyze a variety of reactions. They are very small organelles bound by their plasma membrane. some peroxisomes break down fatty acids to smaller molecules that are transported to mitochondria for fuel. Found both in plant and animal cells. Found in the green leaves of higher plants. They participate in oxidation of substrates resulting in the formation of hydrogen peroxide. They often contain a central core of crystalline material called nucleoid composed of urate oxidase crystals. These bodies are mostly spherical or ovoid and about the size of mitochondria and lysosomes. They are usually closely associated with ER. They are involved in photorespiration in plant cells. j.3 Glyoxysomes The microbodies present in plant cells and morphologically similar to peroxisomes. Found in the cell of yeast and certain fungi and oil rich seeds in plants. Functionally they contain enzymes of fatty acid metabolism involved in the conversion of lipids to carbohydrates during germination. Extending Science Learning: View the following videos available in YouTube for further learning and other references. Note: This is not required but you can watch the videos if you have stable internet connection. Cell Structure at https://youtu. be/URUJDS5NEXC8 The Cell: High School Biology at https://www.youtube.com/watch?v=URUJDSNEXC8 The Plasma Membrane at https://www. youtube.com/watch?v=moPJkCbkjBs The Fluid Mosaic Model for AS Biology at https://www.youtube.com/watch?v=YJhgsl21k6A Introduction to Cytoskeleton at https://www.youtube.com/watch?v=4BAGI6LbHeo Inner Life of the Cell at https://www. youtube.com/watch?v=FzcTgrxMzZk Vi. Practice Tasks Practice Task 1. Label the Cell Parts. A. Direction: Label the animal cell parts and write your answer on the line provided corresponding each number from the illustration below. 10. 11. 12. 13. NOORWN> Practice Task 2: Complete the three basic components of the cell theory by arranging these words in proper order. Write your answer on the space provided after each number. 1. ORGANISMS OF CELLS ARE ALL MORE LIVING COMPOSED OR ONE 2. OF BASIC CELL THE IS UNIT LIFE 3. COME CELLS PRE-EXISTING ALL FROM CELLS Practice Task 3: Organelle Nickname For this activity, use the activity worksheet provided below. Name the organelle that is shown in each picture. For each organelle, tell whether it is membrane-bound or non- membrane bound. Create a nickname for each organelle that is connected to its function and explain. ACTIVITY WORKSHEET Name: Year & Section: Complete each table below. Write the name of each organelle in the blanks. In the second column, indicate whether it is membrane-bound or non-membrane-bound organelle. Create a nickname for each organelle that is connected to its function. Write its function and comparison in the last column. Organelle Membrane- | Nickname Explanation bound/ Non- Membrane- bound Function: In the same way... Function: In the same way... Membrane Function: In the same way... Function: In the same way... Function: In the same way... Function: In the same way...