Chapter 1 - Biology 2nd Secondary PDF

Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Chapter 1: nutrition and digestion in living organisms What is the meaning of nutrition? Nutrition is the scientific study of food and different methods of nutrition of living organisms Th...

Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Chapter 1: nutrition and digestion in living organisms What is the meaning of nutrition? Nutrition is the scientific study of food and different methods of nutrition of living organisms The importance of nutrition: nutrition is the source of energy and needed for growth and repairing our tissues. Types of nutrition: Autotrophic nutrition Heterotrophic nutrition Autotrophs can make their own food by Heterotrophs obtain their nutrition from themselves EG: green plants and some the bodies of the other organisms either bacteria. green plants or animals. Green plants: can synthesize their food Types of heterotrophic nutrition: “high energy food” such as: (sugar, fats 1) Holozoic nutrition: including and proteins) from simple, low energy carnivores, herbivores, and material (CO2, water and minerals) in omnivores. the presence of the light during 2) Parasitism: such as bilharzia and photosynthesis. orobanche plant. Autotrophic nutrition: 3) Saprophytes: such as some fungi and bacteria. Autotrophic nutrition depends on: A) Absorption of water and salts. B) Photosynthesis. The process of absorption of water and salts occurs at the root region specifically at the root hairs. pg. 1 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Structure of root hair: A tubular out-growth of the epidermal cells. Reaches 4mm long. Lined internally with a thin layer of cytoplasm and that contain the nucleus and a large cell vacuole. The lifespan of this entity does not exceed a few days or weeks. (G.R) Because epidermal cells are constantly lost and regenerated from the zone of elongation. So how does the root hair adapt to their function “absorption of salts and water”: A) Thin walls: to allow the passage of the water and salts. B) Numerous number that protrudes outside: to increase the surface area of the absorption. C) The concentration of the salts in the cell vacuole is more concentrated than that of the soil: To facilitate the movement of water from the soil into the root hair. D) Root hair secrets a viscous fluid: To make it easier for the root hair to move through the soil particles and firmly attach to them, ensuring plants are securely anchored. pg. 2 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Water absorption mechanism Depends on several physical phenomena. the movement of molecules or ions from high concentration gradient Diffusion to low concentration gradient [for the solute] Tea steeping: When you put a tea bag into a cup of hot water, the flavor molecules diffuse from the tea leaves into the water, gradually infusing it with the taste and color of the tea. Permeability The ability of wall/membrane to diffuse the molecules and ions through them. Types of the walls/membranes: Walls/membranes Type permeability Ability of permeability a) Cell wall “cellulose”. Fully permeable. Permeable to water and mineral ions. b) Walls that is covered Completely impermeable. Does not permit water and by suberin “bark of ions to pass through. the trees”, cutin and lignin. c) Plasma membrane. Semi-permeable. (G.R) Selective permeability. Allow specific molecules to (G.R) pass through “water As it has tiny pores, allows molecules and some ions.” to control the passage of And prevent the molecules molecules according to the of the following: amino acid, requirements of the cells. glucose, and large-sized regardless of their: size, molecules. concentration, and charge. pg. 3 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Osmosis The net movement of water from high concentrated water medium to low concentrated water medium [for solvent]. In other words, the water diffuses from low concentrated medium” of solute” to high concentrated medium “of solute”. Osmotic pressure: it’s the pressure that causes the diffusion of water through the semi-permeable membrane from the high conc. Water med. To low conc. Water med. “in other words it means the pressure applied to the pure solvent to prevent the osmosis”. the osmotic pressure increases by increasing the solute’s concertation. Imbibition The ability of some hydrophilic colloidal particles to absorb liquids causes them to swell and increase in volume. colloidal particles such as: cellulose, pectin, and protoplasmic proteins. Note: Protoplasm = cytoplasm + nucleus pg. 4 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 absorption of water from soil to root occurs by two pathways: A) The water enters the epidermis by osmosis since the soil is having higher conc. of water while the cell having low conc. of water so, the water moves from outward to inward, after the water enters the cytoplasm of the cell, it begin to pass from a cell to another “trough the cytoplasm” so this movement is called symplastic pathway. B) The cellulosic cell wall of the root hair absorb the water by imbibition, then the water goes through the intercellular spaces, this movement is called Apoplastic pathway. Both pathways lead the water to the “xylem”. Mineral requirements of the plant: Principal elements “key Essential elements elements” (H, O, C) Macro-nutrients Micro-nutrients: (Hydrogen, Oxygen, 7 elements: 8 elements: Carbon) (Mg, Ca, N, Fe, S, P, K) (Al, Mo, Mn, B, I, Cu, Cl, Zn) (Magnesium, Calcium, (Aluminium, Molybdenum, Nitrogen, Iron, Sulphur, Manganese, Zinc, Boron, Iodine, Phosphorus, Potassium) Chlorine, Cupper) All Mothers Make Zealous, Bright, “Many Cats Nap In Sunny Interesting, Creative, Cakes. Places, Kissing Paws.” They are called trace elements as they are needed with very small ratios “few mg./L” They are called co-enzymes as they act as an activator for the enzymes. Both of the macro and micro-nutrients are absorbed by the root hairs from the soil. ⚠️the deficiency of these elements would lead to: ⚠️ a) disturbance in the plant’s growth. b) no production of flowers and fruits. pg. 5 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Minerals absorption mechanism A) Through the cell wall “cellulosic cell wall”: the process of absorbing the minerals from the soil is occurred by diffusion as: 1. Ions moves from high conc. “soil” To low conc. “cell wall”. 2. also a cation exchange may occurs under a A specific conditions. B B) Through a semi-permeable membrane “plasma membrane”: The membrane pass the required ions and molecules only by the plant, regardless their size, charge or concentration. But what if the plant requests for more of a substance it have it already with high concentration? The plant will have to force them to enter it by something called active transport. Active transport: is the passage of any substance through a membrane against the concentration gradient, as it affords “ATP” for their passage, which is released during the Aerobic respiration. To resolve the confusion between the active transport and the selective permeability: An experiment has been done to an algae called Nitella showing the difference between active transport and selective permeability: Analysis of the graph shows: a. The conc. of different ions in the cell sap of the algae is higher than that of the surrounding water, which means the cell consumes a lot of energy to absorb these ions against the concentration gradient. “Active transport” b. The inc. of the conc. of some ions than the others in the cell indicates that the cell select this ion specifically than the other “selective permeability”. pg. 6 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Sugar and oxygen are essential for absorption of salts by the plant roots (G.R) Since O2 and sugar(C6H12O6) are used in the process of aerobic respiration, to release energy required for the active transport to absorb salts from the soil. Compare between Diffusion “Passive transport” VS Active transport. diffusion Active transport Type of phenomena Non-selective selective Movement according to With the conc. gradient “from against the conc. gradient conc. gradient. high to low” “from low to high” Independence of energy Does not depend on ATP Depend on the ATP Importance of living Does not need living membrane Living membrane is essential membrane example Diffusion of salts between the Absorption of salts from the soil particles soil by the root hair. the key difference is that imbibition is more of a physical absorption of water by non- living materials, whereas osmosis is a biological process involving living cells and their membranes. B) Photosynthesis process. Where does this process occur? Occurs mainly at the green leaves & green herbaceous stems as they having chloroplastids at their chlorenchyma cells. It appears to be a green mass having a convex shape. Under light microscope. While under the electron microscope it seems to be more clear since its composed of: A. Thin double membrane: of a thickness 10nm. B. stroma or matrix: that containing proteinic substance absorb Co2. C. Grana: are disc shaped structure embedded inside the stroma each granum is made of 15 or more discs each disc is called from inside and called thylakoid. pg. 7 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 D. the diameter of each granum is about 0.5 micron and its thickness 0.7 micron. E. Each granum protrudes outside to meet the other granum forming a lamellae. Since they are carrying they pigment responsible for absorbing the light, so the lamellae is to increase the surface area to absorb more light. Types of pigments: Pigments colour Molecular formula Percentage Chlorophyll A Blue green C55H72O5N4Mg 70% Chlorophyll B Yellow green C55H70O6N4Mg Carotenoids” Yellow orange red C40H56 30% xanthophyll, carotene, C40H56O2 lycopene” So that the dominant pigment here is green as it presents 70% of the pigments. “Which give the plant its ability to make the photosynthesis process” We have noticed that the starch granules which is found at the chloroplast resulted from the photosynthesis process, is small in size and numerous in number as, this form of store food is temporary as it will be transformed into a simple sugar form later. Note: Its believed that the Mg which is found at the center of the chlorophyll is the reason for absorbing the sun light. pg. 8 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 The composition of leaf: 1) Epidermis. 2) Mesophyll. 3) Vascular tissue. 1) The epidermis: The upper and lower row of epidermis are composed of one adjacent row of barrel liked shaped cells, each is covered by cutin to prevent the water loss in the form of vapour. →These parenchyma cells don’t have chlorophyll. 2) Mesophyll: Lies below the upper and lower epidermis and composed of: Palisade layer Spongy layer Site Below the upper epidermis Above the lower epidermis “below the palisade” Structure Composed of one or more Irregular shaped cells, loosely arranged & cylindrical elongated cells, cells, having wide intercellular spaces to: Function having a great number of 1. Facilitate the gas exchange. plastids, since it exists in the 2. Having lower amount of plastids upper part to absorb much to help in the photosynthesis possible light. process. 3) Vascular tissue: a. The mid rib contains the main vascular bundle. b. The veins and venules extend through the leaf plate. xylem Phloem Facing the upper Lies towards the epidermis lower epidermis pg. 9 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Mechanism of photosynthesis: The role of the light in the photosynthesis and the source of oxygen evolved during photosynthesis: Neil found that the purple bacteria absorb the light to break down the hydrogen sulphate H2S to produce hydrogen that will be used as source for reducing the Co2 to build up the carbohydrates. sunlight H2S H2 + S So, sunlight 6Co2 + 12H2S C6H12O6 +6H2O+12S Same occasion is for the green plants, light is used to decompose the H2O int hydrogen “which is used to reduce “redox reaction” the Co2 to build up the glucose “ and oxygen. sunlight 6Co2 + 12H2O C6H12O6 +6H2O+6O2 Remarkable note: For your knowledge: Oxidation= loss of 2 hydrogen When an electron at its energy level is stimulated by atoms. an external energy source, such as light, the electron OR absorbs this energy and gets excited, moving to a higher energy level. This is what is referred to as an Oxidation= gain of 1 oxygen excited atom. However, after some time, the electron atom. tends to return to its original energy level. Consequently, the absorbed energy must be released Perfect hacks once again. pg. 10 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Photosynthesis Light dependent reaction Light independent Occurs at: the thylakoids “grana” reaction “dark reaction” of the plastid. or Calvin cycle. Limiting factor: light Occurs at: the stroma of the After light fall on the chloroplast. chloroplast, the electrons Limiting factor: temperature get excited. “which means it can occur After a while the electrons during day and night.” will release the energy “this energy will be used in The products of the light- splitting water molecules dependent reaction are and the formation of ATP” used in the dark reaction. The electron “hydrogen The first stable compound ions” are received on the is formed is PGAL NADP. “The last stage of “phosphoglyceraldehyde”. the electron transport PGAL is used to produce chain” glucose, starch, proteins, so, this electron carrier and fats. will reduce into NADPH2 Formation of water. “Nicotinamide Adenine And the final product will Dinucleotide Phosphate, be starch. reduced form”. The oxygen is produced as a byproduct for the photosynthesis process. Reactions: H2O H2 “2H++2e-” +O2 NADP + H2 NADPH2 ADP + P ATP The products of this reaction: 1) ATP. 2) NADPH2. pg. 11 3) Oxygen. Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Calvin used the chlorella algae for his experiment. He also supplied it with a radioactive carbon (C14) After exposing the algae to a source of light for a few seconds with the radioactive carbon he exposed the algae to a hot alcohol which is used to: a) kill the cells “the protoplasm”. b) also, to stop the biochemical reactions “photosynthesis”. The products formed during the photosynthesis were tested for radioactive carbon (C14) by using Geiger counter. As the photosynthesis took for about 2 seconds, a 3-carbon compound was formed which is called PGAL “PhosphoGlycerALdehyde”. That’s why the glucose is formed in more than one step, activated by enzymes. “The products of the light dependent reaction”. Heterotrophic Nutrition: For that type of living organism that can’t make their own food by themselves. Importance of digestion: Since these living organism gets their own food in the form of organic compound that is: 1) Already made. 2) Complex of proteins, starch, and fats. “Large-sized molecules or polymers” 3) Can’t diffuse through a semi-permeable membrane “insoluble in water”. So, the best way to get the full benefit from it ,is to be broken down into smaller molecules that would be: 1) Chemically simple “monomers or small sized molecules” such as: glucose, amino acid, fatty acids and glycerol”. 2) Soluble in water. 3) Easily absorbed through either: diffusion or active transport. pg. 12  Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 The digestion: is the breaking down or the conversion of large molecules (polymers) into its simplest form (monomers) through hydrolysis “catalysed (activated) by enzymes”. Enzymes: a proteinic substance that have the property of catalyst, as it has the ability to activate a specific reaction. “Without being affected”. The specification of the enzymes depends on its SHAPE, which means that each enzyme has its own specific shape that fits only to its own reactant. “like the key-lock paradox” Enzyme + substrate “reacting molecule”. Enzyme-substrate complex “intermediate Comp.” Product +Enzyme “without any changes” Properties of enzyme: 1) Enzymes may have a reversable effect “which means it can go in both ways, breaking down or recombining”. 2) The type of the enzymes is identified according to their secretion state. Some enzymes are secreted in an active form: such as amylase. Some of them are secreted in an inactive form that need a co enzyme to activate it such as: pepsinogen that needs a co enzyme to activate it into pepsin. 3) Enzymes are affected by temperature & PH value. “Every enzyme has its own PH and degree of temperature that make the enzyme at its max effect.” pg. 13 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 The Digestive System In Human: Its composed of: 1) alimentary canal: “which is a long tube extends from the mouth to anus a convoluted parts (coiled parts)” 2) accessory glands: a. 3 pairs of salivary glands. b. liver. c. pancreas. Parts of the digestive system: 1. Mouth 2. Pharynx 3. Oesophagus 4. Stomach 5. Small intestine 6. Large intestine pg. 14 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 1) Mouth The oral cavity composed of: A) teeth, B) tongue, C) 3 pairs of salivary glands. A) Teeth: distinguished into: Incisors: for cutting food Canines: for tearing the food Premolars and molars: for crushing and grinding. Helps in: 1) mixing food with saliva. 2) Increasing the surface area of the food. 3) Facilitate the food swallowing. B) Tongue: for tasting and moving food C) The 3 pairs of salivary gland: secret the saliva in the mouth cavity: Saliva: Components medium source Site of action Function Mucus PH=7.4 3 pairs of Oral cavity Helps to lubricate and Weak alkaline the salivary swallowing food. Salivary amylase medium. glands Starch+H2O (ptyalin) Hydrolysis “amylase” Maltose “Disaccharide”. (Barley sugar) pg. 15 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 2) Pharynx A common pathway “cavity” for both oesophagus and trachea Transport and regulates the passage of air and food through each oesophagus and trachea. Swallowing is considered as a reflex action, as a response to a stimulus (which is the presence of food in the throat). G.R When the food passes through the mouth, the pharynx plugs the raised “elevated “trachea with the epiglottis, to prevent food from getting into trachea. 3) Oesophagus A 25cm tube parallel to the vertebral column It extends in the neck, chest cavity and penetrate the diaphragm to reach the stomach. Composed of : Components Function Mucus glands Lining the oesophagus and help in sliding food by secreting mucus. Circular Responsible for the peristalsis process “ a series of muscles contraction and relaxations” which aims to deliver the food to the stomach. Oesophagus don’t have a digestive role or function. Peristalsis is series of muscle contractions and relaxations responsible for: a) sliding the food in the alimentary canal b) mixing the food with the digestive juices. c) helps in the absorption of the digested food pg. 16 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 4) Stomach Dilated muscular sac in the abdominal cavity. Separated from the oesophagus by a strong muscle called: cardia or cardiac sphincter. Separate from the small intestine with also a strong muscle called pyloric sphincter. Both sphincters control the passage of food into or out of the stomach. Proteinic nutrients are digested mostly in the stomach by the help of the gastric juice “acidic solution”. organ PH value secretion Function Stomach “1.5-2.5” Pepsinogen Once the pepsinogen is activated into the Strong HCl “act as a pepsin” the active for” the digestion of the acid co-factor” proteinic substance occurs by hydrolysis medium HCl helps in: a) the activation of the pepsinogen into pepsin. b) Killing harmful bacteria. c) Stops the action of ptyalin “amylase”. HCl Pepsinogen pepsin. Pepsin enzyme helps in the protein hydrolysis by breaking down the proteins into a smaller form which is, short peptide chains “peptones”. Since the gastric juices are at its peak in an acidic medium for so how it doesn’t hurt the inner wall of the stomach or in other words how stomach doesn’t digest itself? 1) Since the stomach secretes a mucus lining the inner wall of the stomach to protect it from digestion 2) As the pepsinogen enzyme is secreted in an inactive form and get activated while it is in the stomach lumen “cavity”. pg. 17 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 5) Small Intestine An 8 meters tube, with a diameter starts with 3.5cm and ends with 1.5cm The coils and loops of the small intestine are all connected with a mesenteric membrane. The small intestine dissected into sections: a) Duodenum: Its length is about 25cm. b) Jejunum: Its length is about 2.5m. c) Ileum: Its length is about 3.5m. Duodenum act as an entrance gate as it: a) receives :1) the food from the stomach. 2) the secretions of the pancreas and liver through a common opening. b) secretes the intestinal juices. jejunum is the site at which the food digestion and absorption occurs. ileum is the site at which the absorption primarily occurs and passes the remaining of the food “stools” to the large intestine. The digestive secretions at the S. intestine: a) bile juice, b) pancreatic juice c) intestinal juice. pg. 18 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 PH origins Structure Function Bile juice Nil. gall Nil. Emulsify the fats bladder found to be adhering to the liver Pancreatic pancreas a) NaHCO3 Neutralize the HCl effect and Alkaline medium juice make the medium more alkaline. b) Amylase Hydrolyse starch and glycogen. c) Lipase Hydrolyse the fatty emulsion. d) Trypsinogen The enterokinase is a co- Intestinal specific a) Enterokinase enzyme that activate the juice cells in the enzyme trypsinogen “inactive form” walls of the to trypsin “active form”, That S. intestine have the same effect of pepsin and more powerful “hydrolyse the protein into polypeptides”. b) Polypeptidases A group of enzymes that group break down the polypeptide Alkaline medium chains at a certain bond between the amino acids to release the different amino acids. c) Disaccharides 1) Maltase Hydrolyse the maltose into 2 enzymes: glucose. 2) Sucrase Hydrolyse the sucrose into glucose& fructose. Hydrolyse the lactose into 3) Lactase glucose & galactose. pg. 19 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 2) large intestine A 150cm tube & a diameter of 6cm with constrictions and enlargements Surrounds the S. intestine with a reversed U shape. Dissected into the following sections: a) Caecum (blind pouch): a sac found at the beginning of the large intestine. b) Appendix: extends from the caecum as a small appendage. c) Colon: i. Ascending colon. ii. Transverse colon. iii. Descending colon. d) Rectum: extends downwards the descending colon along the left side of the abdomen. e) Anus: an opening at the end of the rectum and controlled by 2 pairs of anal sphincter muscles. Note: The internal Sphincter is involuntary while the External is voluntary. section Function. The constrictions For increasing the absorption of water and minerals. and enlargements Appendix Nil. caecum Absorption of water and nutrients. colon Rectum A site of faeces or stools “undigested food” aggregation. Anus Opening through which the stools are expelled to the outside. pg. 20 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Absorption: This process can be defined as the transferring of the digested food substances to the blood and lymph stream, through the epithelial cells lining the intestine. This process is done by diffusion and active transport. Occurred by these numerous finger-like projections found at the wall of the intestine and called villi. a) Structure of villus: i. Epithelial layer. ii. Encloses a lacteal vessel. iii. This vessel is surrounded by blood capillaries. iv. Contains microvilli on its top to increase the surface area of absorption. b) Function of villi : is the absorption of nutrients in the intestine greatly to reach about 10m2 “about 5 times of the humans’ surface area.” The Routes of The Digested Food: Blood route Lymph route 1) Carry: water, monosaccharides, 1) Carry fatty acids, glycerol, vitamins (K, E, D, A) “fat-soluble mineral salts, amino acids, and vitamins”. water-soluble vitamins. 2) Starts from the lacteal vessels 2) Starts from the blood capillaries inside the villi and then passes inside the villi, passes its directly to the lymphatic vessels. content to the hepatic portal 3) The lymphatic system carries the vein that pours in the liver. fats, to the superior vena cava at 3) From liver to the hepatic vein the right atrium. that pours in the inferior vena Note: some fats can recombine with cava at the right atrium of the epithelial cells to form fats again heart. and passes to the lacteal late. pg. 21 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Large Intestine And The Defecation Process i. The undigested food passed from the small intestine to the large intestine and the process of water and minerals absorption begin.” Occurred by the help of the convolutions of the L. intestine”. ii. The undigested food become in a semi-solid state, at which the bacteria that lives in the L. intestine, decay it. iii. By the help of : a) mucus secreted from by the L. intestine, b) the contraction of the rectum muscles, c) the relaxation of the 2 pairs anal sphincter muscles “internal & external” this facilitate the expelling of the faeces “stools” outside the body through the anal opening. Enzyme’s Scheme enzyme function PH origins Site of Reactions value action ptyalin/water 1) Ptyalin Salivary Starch maltose 6.7 - 7.0 Mouth Hydrolyse the carbohydrates gland amylase/water 2) Amylase duodenum Starch maltose Pancreas” 6.7 - 7.0 poured in duodenum” 3) Maltase 6.0 - 7.0 maltose maltase/water 2 Glucose 4) Sucrase sucrose sucrase/water glucose + 5.5 - 7.5 Small intestine fructose lactase/water 5) lactase lactose glucose + 6.5 - 7.5 galactose 6) lipase emulsified fats and oils. emulsified fats Hydrolyse the duodenum Pancreas” lipase/water 7.0 - 9.0 poured in duodenum” fatty acids + glycerol. 7) Pepsin proteins 1.5 - 2.5 Stomach Hydrolyse the pepsin or trypsin + water proteins 8) Trypsin 7.5 - 8.5 polypeptides 9) Peptidases Varies Small intestine polypeptides peptidases/water A.A (neutral (Amino Acids) range) pg. 22 Biology 2nd secondary Chapter 1 MR. Bavly Ayman / +201211899128 Co-enzymes Scheme Co-enzyme function reaction HCl Activate the pepsinogen Pepsinogen HCl pepsin enzyme Enterokinase Enterokinase Activate the trypsinogen trypsinogen trypsin enzyme Food metabolism It is the process of which the body gets its benefits from the digested and absorbed nutrients. The food metabolism having two types of processes: aspect anabolism Catabolism Definition Set of metabolic processes processes that involve breaking down that build complex molecules complex molecules into simpler ones to from simpler ones, requiring release energy. energy input. Energy Requires energy input; Energy-releasing reactions; production of energy-consuming reactions. ATP for cellular energy. Example Protein synthesis, nucleic acid Glycolysis (breakdown of glucose), citric synthesis (DNA, RNA), acid cycle, breakdown of fats and proteins, photosynthesis(plants), oxidative phosphorylation (ATP synthesis). muscle growth. pg. 23