Science Notes PDF

Scientific Method Steps scientists use to solve problems or discover new things Organized way that help scientists answer a question or begin to solve a problem The Basic Process Skills Needed for Scientific Investigation 1. Observing – Using the 5 senses to gather info...

Scientific Method Steps scientists use to solve problems or discover new things Organized way that help scientists answer a question or begin to solve a problem The Basic Process Skills Needed for Scientific Investigation 1. Observing – Using the 5 senses to gather information 2. Inferring – Providing mental judgments/explanations of the observations 3. Predicting – Stating the way things will happen in the future based on observable facts, trends and patterns 4. Measuring – Determining the size of an object or amount of a material with the use of a measuring tool 5. Comparing – Finding the similarities and differences between two objects 6. Classifying – Grouping/ordering objects or events into categories based on their properties or criteria Steps of the Scientific Method 1. Observing and Identifying the Problem 2. Gathering data about the Problem 3. Formulating the Hypothesis 4. Testing the Hypothesis 5. Analyzing Results 6. Making Conclusion and Recommendations The Chemical Basis of Life Compound ✓ Formed by the chemical combination of two or more elements. Organic – with carbon Inorganic – without carbon Organic Compound Characteristics of an Organic Compound Contains carbon atoms bonded to hydrogen atoms  Often have covalent bonds It can be both naturally occurring and synthetic Common Organic Compounds ✓ Carbohydrates Functions 1. Serve as the backbone of other molecules 2. Act as energy storage (starch, cellulose and glycogen) 3. Most common energy food 4. Combine with proteins to form structural component of the living cells and to perform many other functions. Classification of Carbohydrates 1. Monosaccharides Simple sugars, consist of only one sugar unit Glucose (dextrose or blood sugar) – instant source of energy, easily dissolves in water Galactose (part of lactose)- some atomic structure as glucose, but with different structure Fructose (corn sugar)- sweetest sugar- 10x sweeter than lactose, found in fruits 2. Disaccharides Double sugar, consist of two sugar units 3. Polysaccarides Long chain of simple sugars linked together by dehydration synthesis. Example: Starch – main storage of food for plants Cellulose – forms part of the wall that encloses plants cells. Glycogen – energy storage for animals and other organisms. (animal starch) Chitin – outer coverings of animals such as insects and crustaceans. ✓ Lipids Role of lipids in the body 1. Serve as the highest energy giving food in the body. 2. Act as insulators 3. Serve as a part of the protoplasm of the cell 4. In the form of phospholipids, they form as part of the structure of the cell membrane. 5. Serve as building block for man steroids Forms of Lipids 1. Fatty acids A. Satured – solid at ordinary conditions (margarine and animal fats) B. Unsaturated – liquid at ordinary conditions (vegetable oil and corn oil) 2. Phospoglycerides/Phospholipids Important component of plasma membrane Acts as emulsifying agent: breaks fat into smaller molecules Example: Lecithins – found in egg yolk, brain, yeast and liver Cephalin – found in brain tissues 3. Sphingolipids Found in the brain, lungs and nerve tissues. Example:.b – maintain the right shape of the lungs of the fetus. 4. Waxes Used as lubricants, polishers, and ointments. Protect the surfaces of some leaves 5. Terpenes Chloropyll Carotene Vitamins A, E, and K-fat soluble vitamins Coenzyme Q – cellular respiration, electron transport chain 6. Steroids Cholesterol – helps regulate fluidity in the cell, acids in the transport of materials.  Bile salts – emulsifier in the digestive system. It is made in the liver stored in the gall bladder and goes to the small intestine – breaks fat into smaller globules. Sex hormone – hormone that triggers off a response which makes cell undergo a special process. Estrogen – Female Testosterone/Androgen – Male ✓ Proteins Large, complex molecules that play many critical roles in the body. Role of the Proteins in the body 1. Essential in building and repairing body cells and tissues. 2. Aid in speeding up almost all chemical reactions in the body (enzymes) 3. Bring about individual differences. 4. Transport molecules, reserve food and provide protection as antibodies. ✓ Nucleic Acids Carry genetic information Nucleotides – building clocks of nucleic acid Importance of Nucleic Acids Cell creation The storage and processing of genetic information Protein synthesis Generation of energy cells Inorganic Compound Characteristics of an Organic Compound Generally, do not contain carbon hydrogen bonds. Typically, have simpler structures. Often have high melting and boiling points. Common Inorganic Compounds ✓ Water  Properties of Water 1. Ability to dissolve substances. Water is a universal solvent. 2. Hydrogen-bonding ability High heat capacity High heat of vaporization High heat of fusion ✓ Acids Acidus=”sour” Properties of Acids 1. Have a sour taste 2. Turn blue litmus paper to red (BRA) 3. React with active metals to form hydrogen gas (release hydrogen ions (H+)) 4. Corrosive to the skin (strong acid) Strong Acids Weak Acids -Hydrochloric Acid (HCI) - Citric Acid -Sulfuric Acid (H2SO4) -Boric Acid -Nitric Acid (HNO3) -Ascorbic Acid -Carbonic Acid -Salicylic Acid -Acetic Acid ✓ Bases Properties of Bases 5. They have bitter and feel slippery. 6. Turn red litmus paper to blue. (RBB) 7. Substances that yields hydroxide ions. (-OH) 8. Corrosive to the skin Strong Base: Sodium hydroxide(NaOH) and Potassium hydroxide (KOH) Weak Base: Ammonium hydroxide NH4OH (Ammonia) ✓ Salts Products of neutralization Properties of Salts 1. Neither sour nor bitter  2. Crystals or white crystalline powder 3. Has negatively charged ions (OH-) and positively charged ions (H+). Example: Sodium Chloride (NaCl) Living things Population When similar organisms reside in common environment at a given time. Community A community Is the sum of populations inhabiting a particular area. Ecosystem An ecosystem is a community of organisms and their physical environment interacting together. Cell Theory Discovery of Cells ❖ Cells were first recorded by Robert Hooke around 1665 ❖ He was improving the design of a microscope when he decided to observe a piece of a cork. ❖ Up close, he saw box-like structures. These are what we know as cell walls. ❖ Robert Hooke’s discovery led to the development of the cell theory Cell Theory German scientists Theodor Schwann, Matthias Schleiden, and Rudolph Virchow consecutively developed the classical cell theory It is a principle in Biology that is fundamental to our understanding of all living organisms, summarized into three tenets. 1. All living things are made up of cells.  A living organism can be made of just one cell (like an amoeba) or trillions (like the human body) 2. The cell is the fundamental unit of life. All life functions of an organism happen within the cell. 3. Cells com from pre-existing cells. A cell cannot exist spontaneously nor come out of a nonliving thing Biologist who contributed to the development of cell theory ✓ Hans and Zacharias Janssen ▪ Invented the single-lens microscope and compound microscope (1600’s) ✓ Robert Hooke ▪ Coined the term “CELL” (1665) ▪ Responsible for the beginning of cytology ✓ Antonie Van Leeuwenhoek ▪ Created lenses to refine the microscope ▪ First to observe protozoa, bacteria (animalcules or little animals) free-living and parasitic microscopic protists, sperm cells, blood cells, microscopic nematodes and rotifiers, ND much more ((1674) ✓ Robert Brown ▪ Discovered the nucleus of the cell (1831) ✓ Felix Dujardin ▪ Found out that cells contain a internal substance-sarcode (1835) ▪ Propose a new group of one-celled animals (called protozoans) that he called the Rhizopoda (meaning “rootfeet”). ✓ Jan Evangelista Purkinjie ▪ Coined the term “protoplasm” ▪ Discovered large nerve cells with many branching extensions found in the cortex of the cerebellum of the brain (Purkinje cells; 1837) ✓ Matthias Jakob Schleiden ▪ All plant tissues are composed of cells (1838) ▪ He declared that the cell is the basic building block of all plant matter. ✓ Theodor Schwann ▪ Concluded that animals are composed of cells (1839)  ✓ Robert Remark ▪ Published convincing evidence that cells are derived from other cells as a result of cell division (1852) ✓ Rudolf Virchow ▪ Concluded that omnis cellula e cellula, or cells come from pre- existing cells (1858) Cell Structure Cell Basic and fundamental unit of life, it possesses a highly organized structure that enables it to carry out its vital functions. Structure and Basic Function Nucleus Houses DNA, located in the center of eukaryotic cells. Store genetic information, controlling gene expression ad DNA replication. Contains the nucleolus involved in ribosome synthesis. Cell membrane Surrounds the cell and is a selective barrier between the interior and exterior. Regulating the passage of substances, including nutrients and waste materials. Cytoplasm A gel-like matrix containing water, salts, proteins, and other molecules. Occupies the intracellular space between the cell membrane and the nucleus. Plays a crucial role in biochemical reactions, energy production, and substance transport. Provides structural support to the cell. Protein Synthesis Ribosome o Synthesize proteins, which is crucial for cellular structure, function, and regulation. o Located in the cytoplasm and the rough endoplasmic reticulum. Endoplasmic Reticulum It plays a fundamental role in the transport, processing, and distribution of proteins and lipids within the cell There are two main types of ER: ❖ The Rough Endoplasmic Reticulum (RER) – is studded with ribosomes and is involved in the synthesis and modification of proteins ❖ The Smooth Endoplasmic Reticulum (SER) – specializes in lipid synthesis, carbohydrate metabolism, and detoxification. Golgi Apparatus o Key in the processing and packaging of proteins and lipids produced in the endoplasmic reticulum. o Composed of a series of flattened sacs called cisternae, it acts as the ‘shipping center’ of the cell, sorting and packaging proteins into vesicles for transport and distribution. Energy Supply To carry out vital functions and necessary metabolic processes essential for the proper functioning of the cell an /or organism. Mitochondria o Present in eukaryotic animal and plant cells. Theprimary function is energy generation through cellular respiration (ATP production) “Powerhouse of the Cell” Chloroplasts o Exclusive to plant cells and photosynthetic organisms, chloroplasts carry out photosynthesis, converting solar energy into chemical energy.  o During photosynthesis, the synthesize glucose and other organic compounds using carbon dioxide and water, releasing oxygen as a byproduct. Cellular Digestion It involves breaking down molecules and unwanted materials, enabling the recycling of nutrients and cellular maintenance. Lysosomes o Contain digestive enzymes that break down molecules and unwanted cellular materials. o Facilitate cellular Digestion, by disposing of waste, recycling nutrients, and defending against pathogenic invasions. Peroxisomes o Contain enzymes that degrade hydrogen peroxide and toxic compounds, thereby protecting the cell from oxidative damage. o Play a role in the synthesis and degradation of lipids and bile acids, regulating lipid metabolism and overall homeostasis. Support and Movement Maintaining cellular shape, enabling cellular movement and division, are essential for its functioning and survival. Cytoskeleton Composed of filaments (microtubules, microfilaments, and intermediate filaments) and provides support an enables movement in eukaryotic cells. Stability Intracellular transport Regulates cellular shape Flagella Specialized structures for movement Elongated and enable locomotion in liquid environments, whereas cilia are shorter and create coordinated flow on the cell surface. Cilia Cilia are shorter and create coordinated flow on the cell surface. Storage and Transportation They manage nutrients, eliminate waste, and regulate metabolic processes. Vacuoles Membrane- bound organelles found in plant cells and some animal cells. They store nutrients, water, ions, and waste materials, regulating turgor pressure and osmotic balance. Vacuoles can also be involved in the digestion of substances and serve as a defense mechanism against predators by containing toxins. Vesicles and endosomes Membranous vesicles that transport specific materials between organelles and the cell membrane. Vesicles: They transport materials from the endoplasmic reticulum ad the Golgi apparatus to other destinations. Endosomes: They capture and distribute materials for degradation, recycling, or their incorporation into metabolic pathways.