Daniel Gundayao and Georgene San Nicolas Term 2 Exam Science Reviewer PDF

1.​ Cell Transport Important Concepts - ​ ​ Diffusion ​ Osmosis ​ Active Transport ​ Passive Transport ​ Bulk Transport Cell Membrane and its Parts: FLUID MOSAIC MODEL/PHOSPHOLIPID BILAYER ​ The Fluid Mosaic Model is a semi-permeable membrane. Meaning it is a selec...

1.​ Cell Transport Important Concepts - ​ ​ Diffusion ​ Osmosis ​ Active Transport ​ Passive Transport ​ Bulk Transport Cell Membrane and its Parts: FLUID MOSAIC MODEL/PHOSPHOLIPID BILAYER ​ The Fluid Mosaic Model is a semi-permeable membrane. Meaning it is a selective barrier wherein not everything can enter or pass through it. ​ It is built up of 2 Phospholipid layers ​ Cholesterol - Improves Stability, Fluidity, and makes the cell membrane more compact ​ Phospholipids - Protects and serves as a barrier that makes up majority of the cell membrane structure ​ Membrane Proteins - Helps transport certain molecules and maintain the shape and structure of the cell.  ​ Carrier Proteins: Directly Carries Molecules from one place to another. Think of it as a taxi cab or train to another destination. ​ Channel Proteins: Allows bigger molecules to pass through the cell membrane by acting as a bridge or a pathway from one side to the other. Think of it as a bridge that connects two places together. ​ TAKE NOTE: The Phospholipid Bilayer or Cell membrane is VISCOUS and THIN. Types of Cell Transport: ​ Passive Transport - Allows molecules to move from a High concentration gradient to a Low concentration gradient. -​ Does not require the use of energy/ATP -​ High to Low ​ Types of Passive Transport -​ Simple Diffusion: Movement of Solid and Gas Molecules through a semipermeable membrane. High Concentration Gradient to Low Concentration Gradient -​ Osmosis: Movement of Water Molecules through a semipermeable membrane. High Concentration Gradient to Low Concentration Gradient -​ Facilitated Diffusion: Movement of Solid and Gas Molecules through a semipermeable membrane USING A MEMBRANE PROTEIN. ​ Key Points -  -​ Simple Diffusion, Osmosis, and Facilitated Diffusion DO NOT use ATP or Energy. -​ Both Simple Diffusion and Osmosis DO NOT require the use of Membrane Proteins to transport molecules. -​ All 3 move from a High Concentration Gradient to a Low Concentration Gradient ================================================================ ===== ​ Active Transport - Moves against the usual concentration gradient of molecules. Transports these molecules from a Low Concentration Gradient to a High Concentration Gradient. -​ Requires the use of Energy/ATP -​ Low to High -​ Uses Carrier Proteins to move molecules ================================================================ ===== ​ Bulk Transport - Transports Large Molecules across the cell membrane while making use of ATP as energy. -​ Does not have a concentration gradient -​ Requires ATP or Energy ​ Types of Bulk Transport -​ Endocytosis: Captures big molecules from the outside and engulfs it into the cell membrane (Goes inside Cell Membrane)  -​ Exocytosis: Uses vesicles to release waste products or big molecules out of the cell (Exits Cell Membrane) -​ Vesicle: Used to temporarily store nutrients and molecules within the cell. Formed from the cell membrane. ​ Types of Endocytosis -​ Phagocytosis: Cell Eating -​ Pinocytosis: Cell Drinking -​ Receptor-Mediated Endocytosis: Uses receptors found on the surface of the cell membrane to capture molecules and is then used to form vesicles or tiny food capsules within the cell. ================================================================ ==== 2.​ Light and Dark Reactions (Photosynthesis) Important Concepts - Light Dependent Reactions ​ Photolysis: ​ Stomata ​ Light Independent Reaction (Calvin Cycle) ​ Carbon Fixation ​ Reduction ​ Regeneration Light Dependent Reactions: ​ Light Dependent Reactions - Reactions in photosynthesis that require sunlight and can only take place in daylight. ​ Photosystems - Structures within the Thylakoid that collect sunlight and convert it into chemical energy. -​ There are 2 Photosystems within a Thylakoid. Photosystem1 and Photosystem2. ​ Electric Transport Chain - A cluster of proteins that transfer electrons through a membrane -​ Similar to Photosystems, there are also 2 Electric Transport Chains (ETC) within the thylakoid. ETC 1 and ETC 2 -​ Light Reactions first take place or begin in Photosystem 2 ​ Procedures in Light Reaction (Brief Summary) 1.​ Sunlight strikes the electrons found in Photosystem 2 2.​ The electrons get excited or energized 3.​ The excited electrons move to Electric Transport Chain 1 4.​ As the electrons travel to ETC 1, they lose energy in the form of ATP (Adenosine Triphosphate) 5.​ From ETC 1 the electrons then travel going to Photosystem 1 6.​ During this process, they lose energy once again. Forming ATP Molecules. 7.​ The electrons get excited or energized one last time ​ While this is happening, Photolysis and NADPH formation is taking place simultaneously  1.​ Water molecules in Photosystem 2 are hit by sunlight, splitting into 2 separate components through a process called Photolysis. 2.​ It is specifically broken down into Hydrogen and Oxygen Molecules with Oxygen being considered a waste product. 3.​ The Oxygen is then released into the environment for us humans to breathe while the cell stores and keeps the Hydrogen molecules. 4.​ Hydrogen from the water is combined with a NADP+ molecule. As a result, a NADPH Molecule is formed. ​ Hydrogen + NADP+ = NADPH Photolysis - The breaking down of water molecules through the use of sunlight. It requires the use of energy. Products of Light Reaction - Oxygen:A waste product of Photolysis NADPH and ATP:Useful Energy molecules it will use in the Dark Reactions ================================================================ ==== Dark Reactions/Calvin Cycle: ​ Dark Reactions/Calvin Cycle - The process of the plant making Sugars/Glucose using Carbon Dioxide, ATP, and NADPH. This process is not entirely dependent on the use of sunlight but occurs during day time. ​ The Calvin Cycle was named after Melvin Calvin ​ Dark Reactions take place in the Stroma  ​ Procedures in Dark Reaction (a brief summary) 1.​ After Light Reactions take place, ATP and NADPH move to the Stroma or cytoplasm of the chloroplast. 2.​ In the Calvin Cycle, Carbon Fixation is the first to occur. This is the process by which Carbon Dioxide enters the leaf through the Stomata and is then converted into Carbohydrates. 3.​ After Carbon Fixation, Reduction is the next step in the Calvin Cycle. It is a process wherein ATP and NADPH are used to supply the Dark Reactions. 4.​ As the ATP and NADPH travel, they lose energy. Becoming less energetic versions of themselves. ​ ATP turns into ADP ​ NADPH turns into NADP+ 5.​ These molecules then travel back to the Thylakoid to be used during the Light Reactions. 6.​ After this, Regeneration is the last and final step to occur in the Calvin Cycle. Leftover hydrogen from the Photolysis process is mixed with Carbon Dioxide and turns into sugar in the form of Glucose. This glucose then moves into the mitochondria, powering the daily activities of the plant and serving as its food. ​ Regeneration - Hydrogen is mixed with carbon dioxide and forms Glucose. ​ Carbon Fixation - Carbon Dioxide from the Atmosphere enters the leaves through the Stomata to be then used by the plant in the Dark Reactions. ​ Reduction - The process by which ATP and NADPH supply the energy for Dark Reaction. Turning ATP →ADP and NADPH NADP+. Less energetic forms of the original. Products of Dark Reactions/Calvin Cycle ​ ADP and NADPH: Used by the plant for the next Light Reaction Process ​ Glucose: A valuable product of Photosynthesis. Becomes the plants food, fueling its daily activities. Light Reactions Dark Reactions Site Where they Take Thylakoids Stroma Place  Requirements/Needed Sunlight and Water (h2o) ATP, NADPH, and Carbon Molecules Dioxide (co2) Useful Products ATP, NADPH Glucose, ADP, NADP+ Waste Products Oxygen (o2) ================================================================ ==== IMPORTANT THINGS TO NOTE: ​ When the airway is blocked, GAS EXCHANGE will stop. ​ Asthma affects Oxygen Absorption. ==================================================================== 3. Cellular Respiration -​ Organisms harvest energy to power up their life processes by breaking down organic molecules from food. -​ Cellular respiration refers to the complex process by which energy in the form of ATP is released from food molecules. -​ Takes place in the Mitochondria (the powerhouse of the cell) -​ Food (Mouth) -> Digestion (glucose, amino acid, and fatty acid are circulated through the different parts of the body in the small intestine) -​ C6H12O6 + 6 O2 -> 6 CO2 + 6 H20 + ATP Glucose Oxygen Carbon Water Energy Dioxide -​ Breathing vs. Respiration: ​ Breathing - A physical process that allows animals and humans to come in contact with gases. ​ Respiration - A chemical process that releases energy from organic compounds gradually converting it into energy that is stored in ATP molecules. A.​ Aerobic Respiration -​ Involves processes that release energy by breaking down molecules in the presence of oxygen. 1.​ Glycolysis -​ Location: Cytoplasm -​ In summary, one glucose molecule (six-carbon compound) is broken down into two pyruvic acid molecules (three-carbon compound) to generate two net ATPs and two NADHs. -​ Step 1 - Phosphate groups from two ATP molecules are transferred to the glucose molecule. (Leaving ATP as ADP) Step 2 - The resulting six-carbon compound (glucose) is broken down into two three-carbon compounds containing phosphate groups (from the 2 ATP). Step 3 - Two NADH molecules are produced (phosphate groups produce hydrogen and proton ions to energize NAD+ turning into NADH) and a phosphate group is transferred to each two three-carbon molecules. Step 4 - The three-carbon compound is converted into three carbon pyruvates producing four ATP molecules. = The Glycolysis stage produces a total of 2 ATP and 2 NADH molecules. 2.​ Krebs Cycle / Citric Acid Cycle -​ Location: Mitochondria -​ This cycle occurs twice because there are two-three carbon pyruvates. -​ Step 1 - Acetyl-CoA combines with a four-carbon compound (oxaloacetate) forming a six-carbon compound. Step 2 - 2 carbon atoms are released from the six-carbon compound, resulting in a four-carbon compound. Step 3 - Along with the carbon molecules, hydrogen ions and protons are released and energizes two molecules of NAD+ resulting in NADH. Step 4 - The four-carbon compound releases a phosphate and a molecule of ADP resulting in a molecule of ATP. Step 5 - The same four-carbon compound releases hydrogen ions and protons that energizes one molecule of NAD+ and FAD+ making NADH and FADH. = The Krebs Cycle produces a total of 8 NADH, 2 FADH, and 2 ATP molecules. 1.​ Electron Transport Chain -​ Location: Inner membrane of the mitochondria  -​ Through the last stage, the cell can now use the energy from NADH and FADH molecules to make more ATP molecules. -​ Step 1 - Electrons carried by NADH and FADH are transferred to electron acceptors/transport chains (where hydrogen enters into the intermembrane space of the mitochondria). Step 2 - As electrons are transferred and go from one electron acceptor to another, oxygen molecules pick up these used electrons at the end of the electron transport chain and combine with protons to produce water as a by-product. Step 3 - Hydrogen collected in the intermembrane space goes through the ATP-producing complex where it meets ADP and a phosphate group producing ATP molecules. = The Electron Transport Chain stage produces a total of 34 ATP molecules. Glycolysis: 2 ATP 2 NADH Krebs Cycle: 8 NADH 2 FADH 2 ATP Electron Transport Chain: 10 NADH x 3 = 30 ATP 2 FADH x 2 = 4 ATP (minus the transport of glycolytic NADH) 38 = 36 ATP ATP - 2 ATP B.​ Anaerobic Respiration -​ Fermentation is an anaerobic respiration involved in the breakdown of pyruvic acid without the use of oxygen. -​ This is an alternative for the Krebs Cycle when the body does not have enough oxygen to push through. ​ In other words, it is an alternative pathway/source of energy. 1.​ Alcoholic Fermentation -​ Ethanol and carbon dioxide are produced from pyruvic acid. -​ Commonly used in baking and brewing industries.  -​ This kind of fermentation occurs in the plant cells, yeast cells, and some microorganisms. Ex. Beer and wine 2.​ Lactic Acid Fermentation -​ Lactic acid is produced from pyruvic acid. ​ “Lactic acid” - a colorless syrupy organic acid formed in sour milk and produced in the muscle tissues during strenuous exercise. -​ Produced in the muscles from pyruvate during active activity when the body cannot supply enough oxygen. -​ This is a temporary energy source when oxygen is not available. Ex. We experience cramps because we lack oxygen in that specific muscle. The Body Systems: The Human Respiratory System Nostrils and Nasal Cavity ​ After air enters through the nostrils it gets filtered through coarse hair with mucus that traps dust and particles. It reaches the nasal cavity, where air is warmed and humidified before it reaches the lungs ​ Entry point of oxygen Mouth and Oral Cavity ​ Serves as an alternate entry point for air if nasal passage are blocked Pharynx ​ Connects the nasal cavity and mouth to the trachea ​ Pathway for both air and food Epiglottis ​ Flap-like structure ​ Prevents food from entering the trachea Larynx (voice box) ​ Connects pharynx to trachea  ​ a hollow, tube-shaped organ in the throat that plays a key role in breathing, producing sound, and protecting the airway. Trachea (windpipe) ​ Wide tube that connects the larynx to the bronchi ​ Made up of 16-20 cartilage rings ​ Helps us breathe even when not in an upright position Lungs ​ The main organ of the respiratory system ​ Spongelike organs located in the chest cavity bounded on the sides by the ribs and bottom by the diaphragm ​ Symmetrical but not completely identical (left lung is smaller to give space for the heart) ​ Divided into lobes (the other may function normally even if the other is injured/diseased) Diaphragm ​ large, dome-shaped muscle located at the base of the chest cavity, separating the thoracic (chest) cavity from the abdominal cavity. It plays a crucial role in the respiratory system by facilitating breathing. Bronchi ​ Pathway of oxygen or the main airway into the lungs ​ Branches into a bronchus ​ 2 bronchi (one for left one for right) ​ Equipped with tiny hairs called cilia) Bronchioles ​ Conduits for air ​ Branching air passages inside the lungs Alveoli ​ Where gas exchange occurs ​ Tiny air sacs located at the end of the bronchioles  ​ They inflate and deflate when we breathe —————————————————————— Gas exchange ​ The biological process by which gases like oxygen (O₂) and carbon dioxide (CO₂) are exchanged between an organism and its environment. It is essential for respiration, which provides energy for cellular processes. ​ I.​ The Body Systems: The Human Digestive System Human Digestive System -​ The human digestive system is involved in the breakdown of food into simpler nutrients to be absorbed by the body. -​ The intake of food from these sources and the processes that convert food substances into living matter are known as nutrition. -​ Functions of Digestive System: 1.​ Ingestion: The intake of food into the body ​ Ways to Ingest - 1) Putting it in your mouth 2) For those who have terminal illnesses, they pour liquid nutrients ​ Any mechanism involving the intake of food. 2.​ Digestion: The breakdown of food to basic building blocks Ex. apple – nutrients ​ burger – protein, fats  ​ Ways to Digest - 1.​ Mechanical Digestion: Physical digestion, grinding, chewing, putting physical effort. 2.​ Chemical Digestion: Involve the use of enzymes to break down food molecules. Ex. Chewing with teeth – Mechanical Chewing with saliva – Chemical (from amusoles to bolus) 3.​ Absorption: Digested food materials are taken into the body cells through the bloodstream. 4.​ Egestion: The removal of undigested food/waste/feces. ​ Ways animals get food - 1.​ Suspension Feeding - Suspension feeders capture food particles suspended in water, filtering them through specialized structures. 2.​ Substrate Feeding - Substrate feeders live on or in their food source, consuming it as they burrow or move. 3.​ Fluid Feeding - Fluid feeders obtain nutrients by sucking or licking fluids from their food source, such as nectar or blood. 4.​ Bulk Feeding - Bulk feeders consume large pieces of food, often tearing or chewing it before ingestion. A.​ Digestive Tract -​ Also known as the Gastrointestinal tract. 1.​ Mouth -​ Mechanical digestion: cuts the food into smaller pieces -​ Types of Teeth: ​ Canine – for grasping and tearing food ​ Incisor – for biting and cutting ​ Premolar – for grinding and crushing ​ Molar – for grinding and crushing -​ Chemical digestion: Amylase (saliva) – enzyme digests starch ​ Tongue – helps push the food down to esophagus 2.​ Epiglottis -​ A flap-like cartilage that covers the larynx to make sure no food particles enter the trachea during the swallowing process. -​ Located behind the tongue and in front of the larynx. 3.​ Esophagus -​ A long muscle that connects the mouth to the stomach & the pharynx (throat to the stomach. -​ The esophageal sphincters prevent the content of the stomach from flowing back into the esophagus/throat. -​ “Peristalsis” – a wave-like projection 4.​ Stomach -​ Functions: ​ Food storage – can stretch to fit 2L of food ​ Disinfect food – HCI = ph2 - kills bacteria ​ Chemical Digestion – ○​ Pepsin - an enzyme that breaks down proteins/digests proteins. -​ The stomach continuously churns, so if you don't eat enough food, peptic ulcer will occur, wherein it starts grinding its own walls. = The stomach kills germs, breaks up food, digests proteins, and stores food. 5.​ Small Intestine -​ Over 6 meters long. -​ Functions: ​ Chemical digestion – major organ of digestion (of nutrients) & absorption through the lining of the small intestine. ​ Breaks down food into protein, starch, and fats. At the same time, absorbing nutrients. -​ Structure: 1.​ Jejunum – absorption of nutrients & water 2.​ Ileum – absorption of nutrients & water 3.​ Duodenum – (first section) mixes with digestive juices from the: pancreas, liver, & gallbladder. 6.​ Pancreas -​ Enzymes or digestive juices produced by the pancreas are secreted into the small intestine. ​ It produces enzymes to digest proteins & carbs. ​ Digestive enzymes: -> Digest proteins -> Digest starch 7.​ Liver -​ Produces bile (stored in the gallbladder) ​ “Bile” - A digestive fluid produced by the liver and stored in the gallbladder. It helps break down fats in the small intestine during digestion. -​ Breaks up fats & acts like detergents to breakup fats. 8.​ Gallbladder -​ Small storage organ located inferior and posterior to the liver. ​ The gallbladder is a small storage organ located beneath and behind the liver. It stores and concentrates bile, releasing it into the small intestine to aid in the digestion of fats. -​ Holds bile produced from the liver. 9.​ Large Intestine -​ The absorption of most water occurs in the large intestine (90% water is reabsorbed). -​ Functions: ​ Reabsorbs water – uses 9 liters of water everyday in digestive juices