GenBio Reviewer (Q1) PDF

CHARACTERISTICS OF LIFE 1. Organization of life - Organisms are highly organized structures that consist of one or more cells. 2. Genetic Materials - All living organisms store hereditary information in the form of nucleic acid molecules, such as DNA...

CHARACTERISTICS OF LIFE 1. Organization of life - Organisms are highly organized structures that consist of one or more cells. 2. Genetic Materials - All living organisms store hereditary information in the form of nucleic acid molecules, such as DNA or RNA. 3. Response to Stimuli - Also known as “sensitivity”. 4. Growth and Development - Organisms grow and develop according to specific instructions coded for by their genes. 5. Reproduction - Single-celled organisms reproduce by first duplicating their DNA and then dividing it equally as the cell prepares to divide to form two new cells. - Multicellular organisms produce specialized reproductive cells that will form new individuals. 6. Homeostasis - Also known as “steady state”, the ability of an organism to maintain constant internal conditions. 7. Adaptation - It is a consequence of evolution by natural selection, which operates in every lineage of reproducing organisms. 8. Metabolism - All organisms use a source of energy for their metabolic activities. CELLS - Basic Unit of Life Eukaryotic Cells - Contains membrane-bound organelles such as a nucleus, mitochondria, and an endoplasmic reticulum. - Protozoa, Fungi, Plants, and Animals. Prokaryotic Cells - A type of cell that does not have a true nucleus or membrane-bound organelles. - Bacteria and Archaea.  THE MICROSCOPE Microscopes - Are used to magnify small objects. Lenses - Play a crucial role in magnifying the image of an object. Lentil - The word “lens” is derived from this latin word. Parts of a Microscope 1. Eyepiece Lens - part of the microscope through which you look. 2. Objective Lenses - three or four lenses with a range of different magnifications. 3. Arm - supports and connects the eyepiece lens to the base; also a handle for carrying. 4. Stage - a platform that holds the slide for observation. 5. Slide - a thin piece of glass that holds the specimen. 6. Focus Wheel - used to bring the object in and out of focus. 7. Lamp - provides light to illuminate the specimen, sometimes used with a mirror. 8. Base - supports the microscope. The Contributors 1. Zacharias and Hans Jansen - These Dutch spectacle-makers developed the first compound microscope which consists of at least two lenses in 1590. 2. Robert Hooke - In 1665, using the microscope that he built, he observed small components in a thin slice of cork, which he named “cellula” (became known as cells). 3. Antoine Van Leeuwenhoek - His microscopes consisted of a small glass ball set inside a metal frame. - Used his microscopes to observe freshwater single-celled microorganisms that he called “animalcules”. 4. Robert Brown - In 1830, identified a darkly staining structure at the center of every cell. He referred to such a structure as the nucleus.  THE CELL THEORY Mathias Schleiden - A German botanist that proposed the results of his experiments in 1838 that all plants are made up of cells. Theodor Schwann - A German physiologist in 1839 that observed and proposed that all animals are made up of cells. Rudolf Virchow - A German pathologist in 1858 that concluded that cells reproduce by forming new cells. The Cell Theory - Establishes that the cell is a fundamental structural, functional, and reproductive unit of all organisms and provides an operational definition of life. 1. All organisms are composed of one or more cells. 2. The cell is the basic unit structure and function of all organisms. 3. All cells arise from pre-existing cells. SPONTANEOUS GENERATION - States that organisms can come from nonliving sources. - The theory of spontaneous generation was generally accepted until the 19th century. - First comprehensively posited by Aristotle in his book “On the Generation of Animals” around 350 B.C.. Aristotle - Theorized that non-living matter contained a “vital heat” called pneuma— the concept of a “breath of life” and translated later as “anima” meaning “soul” in Latin— and a combination of the four elements believed to make up all life: earth, air, fire, and water. Examples: Wet soil after a flood was believed to create amphibians such as frogs and toads. Oyster shells were believed to form as the earth solidified around them and the “vital heat” grew the creature within.  THE DISPROVING OF SPONTANEOUS GENERATION THEORY Francesco Redi (1626-1697) - Was an Italian physician and the first scientists to suspect that the theory of spontaneous generation may be flawed. - Experimented with meat. John Needham (1731-1781) - An English naturalist that conducted an experiment over 100 years after the theory of spontaneous generation was first proposed. - Experimented with broth but didn’t cover the flask. Lazzaro Spallanzani (1729-1799) - An Italian scientist that contradicted Needham’s experiment on spontaneous generation. - Experimented with broth and covered the flask. Louis Pasteur (1822-1895) - In 1859, this French scientist designed a series of flasks with the necks bent into an S shape. THE PLASMA MEMBRANE Major Components of Plasma Membrane Phospholipids make up the majority of the cell membrane Cholesterol found in between the phospholipids and acts as a fluidity buffer Proteins can be found on the surface or embedded across the cell membrane and involved in the transport of materials in and out of the cell membrane Carbohydrates generally attached to proteins and lipids on the surface of the cell membrane. Phospholipid - Has a hydrophilic head composed of a phosphate. - Has two hydrophobic tails made up of long hydrocarbon chains containing either a saturated or an unsaturated fatty acid. Cholesterol - Helps maintain the fluidity of the cell membrane. - Also maintain the structure of the cell. Proteins - Make up the second major component of plasma membranes. - Proteins found only on the surface of the cell are called peripheral proteins. - Those that cross the bilayer are called integral proteins. Function of Proteins Peripheral Proteins Integral Proteins - Loosely bound to the surface of the - Penetrate lipid bilayer membrane - Transport proteins - Cell surface identity marker (antigen) Carbohydrates - The third major component of the cell membrane. - Plays a key role in cell-cell recognition. Two Types of Carbohydrate in Membrane Glycolipid Glycoprotein - A lipid molecule that has one or - A protein molecule that has one or more carbohydrate units covalently more carbohydrate units covalently bonded to it and an essential part bonded to it. of the cell membrane. - Identifies the cell type and allows it - Acts as receptors at the surface of to bind with other ce;;s of the same the red blood cell type. - Helps determine the blood group of - Repels other cell types and other an individual particles. Passive Transport - A membrane-crossing mechanism that requires no energy input. Diffusion - The spontaneous spreading of atoms or molecules through fluid or gas. - Five Factors that influence diffusion: a. Concentration b. Temperature c. Charge d. Molecule Size e. Pressure Simple Diffusion - Movement of particles from high to low concentration without a protein. Facilitated Diffusion - Movement of particles from high to low concentration using a protein. Osmosis - Movement of solvent from low to high solute concentration. Active Transport - Solutes required for many cellular processes must be moved across a membrane against their concentration gradient, and this requires energy. Sodium-Potassium Pump - This protein actively transports sodium ions (Na+) from the cytoplasm to extracellular fluid and potassium ions (K+) in the other direction. - ATP provides the energy required for transporting both ions against their concentration gradient. Endocytosis a. Phagocytosis - Also called “Cell Eating”. - The cell which is called a phagocyte engulfs large solid objects. b. Pinocytosis - A pit in the plasma membrane traps any fluid, solutes, and particles near the cell’s surface in a vesicle as it sinks into the cytoplasm. c. Receptor-mediated endocytosis - Cell surface receptors bind a target molecule and trigger a pit to form in the plasma membrane. Exocytosis - A vesicle in the cytoplasm fuses with the plasma membrane. KINGDOM OF FUNGI - A fungus is a spore-forming, eukaryotic heterotroph that digests its food externally. - It secretes enzymes onto food, and then absorbs nutrients released by the action of the enzymes. Fungus Structure - Fungi include both single-celled and multicellular species. KINGDOM MONERA Eubacteria - Are unicellular organisms. - Described using their shape: Spherical, Rod-like, Spiral Archaebacteria - Are extremophiles, which means they can live in very harsh environments. - There are several groups of Archaebacteria: a. Halophiles - means “salt loving” in greek. Organisms that live in high salt concentration. b. Thermophiles - derived from the Greek word thermostat meaning heat and philia meaning love (heat loving organism). Organisms that grow at >45 degrees C. c. Acidophiles - or acidophilic organisms are those that thrive under highly acidic conditions (usually at pH 2.0 below). d. Methanogens - Microorganisms that produce methane as a metabolic byproduct in hypoxic conditions. They require anaerobic conditions. KINGDOM PROTISTA - Eukaryotes that are not fungi, plants, or animals are collectively referred to as protists. - The term is derived from the Greek protistos, meaning “the very first”. - Protists include the oldest eukaryote lineages. Plasmodium - Causes malaria, a disease that kills more than 500,000 people each year. - Transmitted from person to person by mosquitoes. The members of this kingdom include: a. Protozoa: Animal Like Are classified on the basis of the motility structure of their cells. Ingestive or Heterotrophs. 1. Ameboid - Members of the group Sarcodina move by pseudopodia, cellular projections that act like false feet. 2. Cilitates - Members of the group Ciliaphora are propelled by rows of cilia that beat with synchronized wavelike motion. 3. Sporozoa - Lack specialized organelles of motility. 4. Flagellates - Members of the group Mastigophora typically move by long, whiplike flagella. b. Algae: Plant Like All undergo photosynthesis. Many contain the green pigment chlorophyll and others contain an accessory pigment that absorbs additional wavelengths of light. Produce most O2 on earth. Classified by pigment types/color group, food storage, cell wall composition. 1. Euglena - Single-cell flagellates eukaryotes. - Known as freshwater algae, but some species are found in saltwater. 2. Diatom - May either be unicellular or colonial. - The siliceous cell wall encloses the organs of the cell and has ornamented and complex structures. 3. Dinoflagellates - Photosynthetic algae with two flagella. - Causes “Red Tide” with overpopulation. - Are mostly marine plankton, but they also are common in freshwater habitats.  4. Red Algae - Contain phycoerythrin pigment that reflects red light and absorbs blue light. - Some may appear green or bluish due to the presence of other pigments. 5. Green Algae - Shares many characteristics with plants, including their photosynthetic pigments and cell wall composition, but unlike plants, they are primarily aquatic. 6. Brown Algae - Are multicellular and have a brown or greenish-brown color due to the predominance of brown and green pigments. - Fucoxanthin, a brown pigment, is found naturally in some types of seaweed like wakame. c. Slime Molds: Fungus Like Found in damp places that are rich in organic matter. Plays key roles in the recycling of organic material. The Slime Molds is also called Plasmodium. It grows in moist and shady places and produces many pseudopodia, which help in amoeboid movement.