Biology 1st Quarterly Reviewer PDF

1ST QUARTERLY REVIEWER Biology Lesson 1.1: Cell Theory ★ Robert Hooke (English physicist) ○ he was the first person to describe the image of a cork and other plant tissue in 166...

1ST QUARTERLY REVIEWER Biology Lesson 1.1: Cell Theory ★ Robert Hooke (English physicist) ○ he was the first person to describe the image of a cork and other plant tissue in 1665 ○ he introduced the term cell (cellula) because the cellulose walls of dead cork cells reminded him of the blocks of cells occupied by monks ★ Timeline/Proponents of the Cell Theory ○ Hans & Zacharias Jenssen (1590) - Produced the first compound microscope ○ Robert Hooke (1665) - First to call spaces in cork “cells” ○ Anton van-Leeuwenhoek (1680s) - Observed living cells through a simple microscope ○ Matthias Jakob Schleiden (1838) - Discovered that plants are made of cells ○ Rudolf Virchow (1855) - Stated that living things come from other living things (“Omnis cellula e cellulae”) ★ Postulates of the Cell Theory 1. All living organisms are composed of one or more cells. 2. The cell is the basic unit of life. 3. Cells arise from pre-existing cells. Lesson 1.2: Prokaryotic and Eukaryotic Cell Structures & Their Functions Cell Organelles & Their Functions ★ Eukaryotic Cell ❖ Nucleus Brain of the cell Responsible for storing the cell’s hereditary material or the DNA. Regulates and controls all cell activities Present only in eukaryotic cell ❖ Nuclear membrane “Gate of the nucleus” Surrounds and protects the nucleus Controls the movement of materials in and out of the nucleus Present only in eukaryotic cell ❖ Endoplasmic Reticulum Where proteins and lipids are synthesized Transports materials within the cell Two types of Endoplasmic Reticulum: Rough endoplasmic reticulum (rER) - ribosomes attached, produces secretory proteins Smooth endoplasmic reticulum (sER) - no ribosomes attached, produces lipids Present only in eukaryotic cell ❖ Golgi Apparatus “Post office of the cell” Flattened membrane-bound sacs Sorts, modifies, and packages macromolecules such as lipids and proteins Make lysosomes Golgi apparatus was discovered in 1898 by an Italian biologist Camillo Golgi Present only in eukaryotic cell ❖ Ribosomes “Protein factories” Site of protein synthesis Ribosomes synthesize proteins by translating information encoded in messenger ribonucleic acid (mRNA) Present in both eukaryotic and prokaryotic cell ❖ Mitochondria “Powerhouse of the cell” Responsible for extracting energy from food through cellular respiration Energy is released in the form of ATP (adenosine triphosphate) Present only in eukaryotic cell ❖ Cell Membrane “Gate of the cell” Also called the plasma membrane Separates the interior of the cell from the outside environment Consists of semi-permeable phospholipid bilayer Holds and protects the cell Controls the movement of materials in and out of the cell Present in both eukaryotic and prokaryotic cell ❖ Cytosol Cytosol is a fluid present in the cell membrane Present in both eukaryotic and prokaryotic cell ❖ Cytoplasm “Area where cell parts move” Cytoplasm is a cell component present inside the cell membrane It is a watery, gel-like material in which cell parts and enzymes are suspended Present in eukaryotic and prokaryotic cell ❖ Lysosome “Waste disposal and recycling enters” Contains digestive enzymes to break down waste materials and cellular debris Mainly found in animal cells, and rarely found in plant and prokaryotic cells. ❖ Peroxisomes “Detoxification centers” Break down fatty acids and produce hydrogen peroxide, which is then converted to water and oxygen Present only iin eukaryotic cell ❖ Vacuoles Membranous storage sacs Stores cell sap (water, organic, and inorganic substances) They can even store waste products, so the rest of the cell is protected from contamination Larger in plant cells Present only in plant cell ❖ Cytoskeleton “Scaffold of the cell” Provides structural support and shape to the cell Facilitates movement of materials within the cell Present only in eukaryotic cell ❖ Centrioles “Microtubule organizing centers (in animal cells)” Involved in organizing microtubules (kind of cytoskeleton) during cell division Present in animal cells only Plant cells have spindle fiber outside the nuclear envelope so they do not need centriole during cell division ❖ Microtubules “Part of the cytoskeleton” Provide structural support Involved in intracellular transport and cell division Present only in eukaryotic cell ❖ Microfilaments “Part of the cytoskeleton” Support cell shape and are involved in cell movement Present only in eukaryotic cell ❖ Intermediate Filaments “Part of the cytoskeleton” Provide mechanical support and stability to cells Present in eukaryotic cells only ❖ Centrosome A region near the nucleus where a pair of centrioles is confined During cell division, centrosomes and centrioles form the microtubules (mitotic spindle fibers) which aline the chromosomes and separate the sister chromatids Present in animal cells only ❖ Chloroplast Disc-shaped organelles found in the cytosol of the cell Contains green pigment called chlorophyll which helps in manufacture of food through the process of photosynthesis Found only in plant cells ★ Prokaryotic Cell ❖ Capsule “Protective layer” Protects the cell from desiccation and phagocytosis Can help with adherence to surfaces It is composed of a thick polysaccharide which covers the outside of the cell wall It is used to stick cells together and works as a food reserve and it also protects the cell from dryness and chemicals Present only in prokaryotic cell ❖ Cell wall “Supporter and protector” It is made from the glycoprotein murein Surrounds and protects the cell Provides structural support and rigidity Present in prokaryotic and plant cell ❖ Pili “Adhesion structures” Helps with attachment to surfaces and other cells Can facilitate the exchange of a genetic material Short protein appendages, which fixes bacteria to surfaces These pili are smaller than those flagella and are used in conjugation to exchange the genetic information Present only in prokaryotic cell ❖ Nucleiod region “Genetic material region” Contains the cell’s genetic material (DNA) Not enclosed by a membrane Present only in prokaryotic cell ❖ Flagella “Movement organelle” Provides locomotion by spinning like a propeller Present only in prokaryotic cell ❖ Plasmids “Extra genetic material” Small, circular DNA molecules separate from chromosomal DNA Can carry genes beneficial for survival Plasmid plays a vital role in exchanging DNA between the bacterial cells Bacterial cells have many plasmids Present only in prokaryotic cell ❖ Inclusion Bodies “Storage compartments” Store nutrients and other substances, such as lipids and starch Present only in prokaryotic cell ❖ Fimbriae “Adhesion structures” Helps with adherence to surfaces and tissues, usually shorter and more numerous than pili Present only in prokaryotic cell Lesson 1.3: Plant Tissues Plants are multicellular eukaryotes whose bodies are composed of organs, tissues, and cells with highly specialized functions. Different cell types comprise each tissue type, and the structure of each cell type influences the function of the tissue it comprises. Each plant organ (leaf, stem, and root) possesses different types of tissue. ★ Vascular Plant ○ A mature vascular plant (any plant other than mosses and liverworts), contains several types of differentiated cells. These are grouped together in tissues. Some tissues contain only one type of cell. Some consist of several. ○ Vascular plants have two distinct organ systems: the shoot system and the root system. ○ The shoot system consists of: Stems, leaves, flowers, fruits It generally grows above ground, where it absorbs the light needed for photosynthesis ○ The root system: Supports the plants Absorbs water and minerals Is usually underground ★ Merismatic Tissue ○ Carl Wilhelm von Nägeli coined the term “meristem.” ○ Meristematic tissue contains undifferentiated cells, which are the building blocks of the specialized plant structures ○ Meristematic tissues contain living cells with varied shapes. ○ They possess a large nucleus devoid of the vacuole. ○ The cells have no intercellular space. The zone where these cells exist is known as meristem. ○ The cells of the meristematic tissue divide actively to form specialized structures such as buds of leaves and flowers, tips of roots and shoots, etc. These cells help to increase the length and girth of the plant. ○ Characteristics of Meristematic Tissue: 1. The cells of these tissues are commonly called meristems. 2. The meristematic tissue has the quality of self-renewal. Every time the cell divides, one cell remains identical to the parent cell, and the others form specialized structures. 3. They have very small and few vacuoles. 4. The meristematic tissue is living and thin-walled. 5. The protoplasm of the cells is very dense. 6. The meristematic tissues heal the wounds of an injured plant. 7. The cells of the meristematic tissue are young and immature. 8. They do not store food. 9. They exhibit a very high metabolic activity. 10. They possess a single, large, and prominent nucleus.  ○ Types of Mertistematic Tissue: Apical Meristems – The apical meristem is located at the tips of roots and shoots and is responsible for the growth in height of plants through cell divisions and cellular enlargement. It consists of the pro meristem zone with actively dividing cells and the meristematic zone containing protoderm, procambium, and ground meristem. Intercalary Meristems – Intercalary meristem is found in the leaves and internodes, typically in grass, monocots, and pines. It contributes to the elongation of the internode and is part of the apical meristem, aiding in plant growth. Lateral Meristems – Lateral meristems are found in the side of stems and roots, increasing plant thickness. Vascular cambium and cork cambium are two types of lateral meristems that divide radially, giving rise to secondary permanent tissues. ★ Permanent Tissue ○ The tissues that are completely grown and have lost the ability to divide are known as permanent tissues. The meristematic tissues divide and differentiate to form permanent tissues. ○ Types of Permanent Tissue Simple Permanent Tissue - these are also known as homogeneous tissues. They are made up of a single cell type, usually with the same origin, structure, and function. They are classified into three types: parenchyma, collenchyma, and sclerenchyma. Parenchyma: found in plant leaves found in outer & inner layers of stems & roots main components of plant ground tissue main components of the soft tissue of fruits located between the xylem & phloem assist in the exchange of water, minerals, & nutrients not as specialized as other cells have thin walls found in dermal, ground, & vascular tissue systems help to synthesize and store organic products in the plant the middle tissue layer of leaves (mesophyll) is composed of parenchyma cells, and it is this layer that contains plant chloroplasts. Sclerenchyma: support the plant unlike collenchyma cells, have a hardening agent in their cell walls & are much more rigid have thick secondary cell walls  are non-living once matured Collenchyma: support young plants are elongated in shape have thick primary cell walls composed of the carbohydrate polymers cellulose and pectin can provide structural support for tissues are able to stretch along with the plant as it grows are found in the cortex (the layer between the epidermis and vascular tissue) of stems & along leaf veins Complex Permanent Tissue - these are made up of various types of cells carrying out distinct functions and are of two types: xylem and phloem. Xylem: water-conducting cells hard cells that bring water up to the leaves do not live past maturity but their cell wall remains to allow water to flow freely through the plant Phloem: transport organic nutrients throughout the plant (such as glucose produced by the leaves) with sieve tube elements as conducting cells cells of sieve tube elements have few organelles allowing for easier passage of nutrients Since sieve tube elements lack organelles (such as ribosomes and vacuoles), specialized parenchyma cells, called companion cells, must carry out metabolic functions for sieve tube elements. Phloem also contains sclerenchyma cells that provide structural support by increasing rigidity and flexibility.