Plant and Animal Nutrition

• Nutrition is the process where living organisms get and use food for growth, metabolism, and repair, including nutrient intake, digestion, absorption, and assimilation.
• Nutrients are essential for energy, tissue building and repair, and regulation of bodily functions.
• Nutrition is vital for survival and development in all organisms.
• Plants require nutrients such as carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur for photosynthesis and metabolism.
• Animals obtain essential nutrients like carbohydrates, proteins, fats, vitamins, and minerals by consuming plants or other organisms which supports energy, growth, and tissue repair and overall health.

Plant Nutrition

• Autotrophs produce their own food, storing chemical energy as carbohydrates via photosynthesis.
• Plants, algae, and some bacteria are autotrophs that supply energy and carbon and form the base of food chains.
• Heterotrophs cannot produce their own food, consuming other organisms for energy, and include animals, fungi, many protists, and bacteria.
• Heterotrophs depend on autotrophs for food.
• Life requires a constant energy supply because heterotrophic life would not survive without autotrophs

Autotrophic Nutrition

• Autotrophs create food via photosynthesis and chemosynthesis.
• Photosynthesis is where green plants and organisms use light energy to convert water and carbon dioxide into oxygen and glucose within chloroplasts using chlorophyll.
• Light-dependent reactions occur in the thylakoid membranes where light energy splits water into oxygen, protons, and electrons, making ATP and NADPH for energy storage.
• Light-independent reactions (Calvin Cycle) occur in the stroma, using ATP and NADPH to fix carbon dioxide into glucose through enzymatic reactions.
• Chemosynthesis uses chemical energy from inorganic compounds like hydrogen sulfide(H2S), methane(CH4), or ammonia(NH3), using carbon dioxide or methane as a carbon source.
• Chemosynthesis produces organic matter like glucose.
• Chemosynthetic reactions occur in cold seeps, with microbes forming food webs using methane or hydrogen sulfide.
• Chemosynthetic bacteria communities metabolize metals around sunken ships.

Heterotrophic Plants

• Heterotrophic plants cannot produce their own food or perform photosynthesis, absorbing nutrients and aquiring them from outside.
• Parasitic nutrition involves an organism (parasite) damaging another by feeding on its nutrition.
• Saprophytic nutrition involves saprophytes feeding on decayed and dead organic matter, releasing digestive fluids and absorbing simpler nutrients via cell membranes.
• Holozoic nutrition involves consuming complex foods and processing them internally, absorbing nutrients and expelling undigested substances.

Nutritional Requirements of Plants

• Essential nutrients, including carbohydrates, proteins, fats, vitamins, minerals, and water support energy production, growth, and physiological functions.
• Proteins are required for tissue repair, while vitamins and minerals boost immunity, bone health, and metabolism.
• Macronutrients like nitrogen, phosphorus, potassium, magnesium, sulfur, and calcium are needed in large quantities for growth and development.

Macronutrients and their Roles

• Nitrogen is essential for chlorophyll production, amino acid synthesis, and overall plant growth/metabolism and a deficiency can cause Chlorosis, stunted plant growth, reduce crop yields.

• Phosphorus is key for energy transfer (ATP), nucleic acid synthesis (DNA, RNA), root development, flowering, and fruit production and deficiency can cause stunted growth, reduced flowering, and poor root development.

• Potassium is vital for water balance in cells, enzyme activation, nutrient transport, and regulation of stomatal opening/closing and deficiency can cause stunted leaf scorching, growth, and reduced disease resistance.

• Magnesium is a component of chlorophyll, activates enzymes for energy production and protein synthesis, and deficiency can cause interveinal chlorosis.

• Sulfur is used to synthesize amino acids, proteins, and vitamins, and supports enzyme function and chlorophyll formation and deficiency can cause yellowing of young new leaves stunted growth.

• Calcium strengthens cell walls, crucial for root development and nutrient absorption anddeficiency can cause deformed new growth, blossom end rot in tomatoes peppers and a tip burn in lettuce.

• Micronutrients such as iron, manganese, zinc, copper, boron, molybdenum, and chlorine are needed in small amounts for enzyme function and metabolism.

• Iron use is for chlorophyll synthesis and respiration and Chlorosis (yellowing of young leaves with green veins) can result from a deficiency.

• Manganese supports photosynthesis, nitrogen metabolism, and enzyme activation, and deficiency can cause Mottled chlorosis, necrotic spots on leaves.

• Zinc use is for hormone Production and enzyme function and deficiency can cause Reduced leaf size, shortened internodes (rosetting).

• Copper use is for Photosynthesis, respiration and seed formation and deficiency can cause stunted growth, blue-green leaves, dieback of young shoots

• Boron use if for cell wall formation, flower development and fruit production and deficiency can cause death of terminal buds, brittle leaves, poor flower and fruit development.

• Molybdenum use is for nitrogen fixation and enzyme function can deficiency can cause General chlorosis, nitrogen deficiency symptoms

• Chlorine use is for regulation of osmosis and maintenance of ionic balance in plant cells and deficincey can cause wilting, chlorosis, and necrosis of leaves.

Specialized Absorptive Structures of Plants

• Root hairs are extensions of root's outer epidermal layer, forming specialized epidermal cells and help with water & nutrient absorption, soil interaction for nutrient uptake and stabilization of young seedlings
• Root hair structure includes extensions of the epidermis in the Zone of Maturation, located third zone from the root tip and preceded by the Zone of Cell Division and Zone of Elongation
• Root nodules are knob-like structures on leguminous roots, formed through symbiosis with nitrogen-fixing bacteria like Rhizobium.
• Legume roots develop lateral roots and nitrogen-fixing nodules.
• Indeterminate nodules grow continuously with developmental zones, including: active meristem, infection zone, nitrogen-fixing zone, and senescent zone like peas and clovers
• Determinate nodules stop growth after formation, such as soybean and peanut.

Root Nodule Formation Steps

• When soil nitrogen is low, legumes and rhizobia communicate to form nodules,

• First, flavonoids attract rhizobia after which nod factors from rhizobia cause root hair curling.

• Developmental changes then occur, including membrane depolarization and cell division.

• An infection thread forms, allowing bacteria to enter root cells then rhizobia enter cortex cells and are enclosed in symbiosomes.

• Chemical signals from rhizobia trigger cell division and nodule formation via a calcium-dependent pathway.

• Cytokinin aids in nodule development and bacteroids fix nitrogen inside nodules; vascular tissues form for nutrient exchange

• Nodulation factors include soil nitrogen levels, oxygen sensitivity, plant hormones and environmental conditions

• Mycorrhizae represent symbiotic partnerships between fungi and plant roots for nutrient and water uptake.

• Key functions include enhanced water and nutrient absorption, an increased root system, and improved drought tolerance and nutrient availability in poor soils.

• Ectomycorrhizae form a fungal sheath on the outside of plant roots.

• Endomycorrhizae penetrate into the root tissue.

Routes for the Absorption of Water and Minerals Across Roots

• Symplast and Apoplast are used for the absorption of water and minerals by roots.
• Active absorption is where water enters the cell sap and moves from cell to cell involving protoplasm, called symplast. While Passive absorption involves water moving through the apoplast of the root.
• Apoplast and symplast are two pathways for water and ion movement along with ions from root hair via root cortex to xylem elements.
• Apoplast is the space outside the plasma membrane where water and ions diffuse freely, not involving protoplasm but involves nonliving parts.
• An apoplast pathway moves water through cell walls from root hair to xylem, where the Casparian strip blocks movement beyond the cortex.
• Symplast is a cytoplasmic network of every plant cell interconnected by plasmodesmata and considered the living part of the plant tissue.
• Symplastic pathways enable water and ions move via plasmodesmata, regulating the intake through selective plasma membranes.
• Casparian strip prevents apoplastic flow, directing water into the symplast.

Nutritional Adaptation by Plants

• Plants have nutritional adaptations to survive in different environments, including nitrogen fixation and mycorrhizal symbiosis.
• Nitrogen is an essential macronutrient which plants are unable to use directly in atmospheric nitrogen.
• Symbiotic relationships with nitrogen-fixing bacteria like Rhizobium enable the plant to be able to use nitrogen
• Mycorrhizae involves a symbiosis between Fungi and plants for nutrient and water absorption especially phosphorus.
• Through mycorrhization, plants obtain phosphates, zinc, and copper. Fungi get sugars from roots which are most beneficial in poor soils & increase root surface area, protect against pathogens, & may even produce antibiotics

Animal Nutrition

• Animal nutrition studies food composition & processing by animals including nutrient requirements, metabolism & performance.
• Animals need organic and inorganic nutrients to repair old and generate new tissue.
• Organic nutrients include carbohydrates, proteins, lipids(fats), vitamins, and inorganic nutrients are primarily minerals.
• Proteins are composed of amino acids for tissue repair, growth & enzyme production.
• Carbohydrates are a primary energy source.
• Simple sugars provide fast energy & complex carbohydrates offer sustained energy.
• Lipids provide energy, helps insulation of the body and supports cell structure and include essential omega-3 & omega-6 fatty acids
• Vitamins are coenzymes in metabolic processes.

Main Stages of Food Processing

• Ingestion is the process of taking food into the body
• Digestion is the process of breaking down food into smaller absorbable molecules which can occur mechanically (chewing) or chemically (enzymes).
• Amylase, protease (e.g., pepsin and trypsin), and lipase break down carbohydrates, proteins, and lipids, respectively.
• Active transport requires energy to move nutrients against their concentration gradient.
• Passive diffusion which includes Nutrients move down their concentration gradient without energy.
• Facilitated diffusion which includes Nutrients move down their concentration gradient with the help of transport proteins
• Absorption is nutrients from digested food that are taken up into the bloodstream.
• Elimination is the process of removal of undigested waste from the body.

Organs Involved in Human Digestive System

• Digestion starts in the mouth through mechanical and chemical processes called mastication involving Teeth.
• Enzymes are found in saliva called salivary amylase (ptyalin or alpha-amylase) and lingual lipase to help breakdown food.
• After oral cavity digestion, bolus(partially digested food) is swallowed into the esophagus,
• During swallowing the food moves towards the pharynx is then stopped from entering the trachea by the epiglottis.
• The upper esophageal sphincter acts as a gate, opening when food or liquid approaches and staying closed when not in use.
• Peristalsis allows esophogus contractions that push food the food downward through the diaphragm to the lower espohageal spinchter
• The stomach processes mechanical and chemical digestion to break down into smaller particles for absorption
• Mechanical Digestion occurs via contractions moving food grinding food pylorus until broken down small enough
• Specialized glands secrete enzymes and acids needed. Parietal cells produce hydrochloric acid (HCI) & chief cells secrete pepsinogen Mucous cells release protective mucus & G-cells produce gastrin to acid secretion for help.
• Gastric juice breaks down food into chyme and it's components are hydrochloric acid (HCI), pepsin, gastric lipase and electrolytes.
• Hydrochloric Acid (HCI) that creates an acidic environment to kill harmful microorganisms.
• Pepsin is a digestive enzyme that breaks down proteins by targeting amino acids.
• Gastric Lipase – Initiates the breakdown of fats by targeting triacylglycerides to help degrade proteins, carbohydrates and releases beneficial phytochemicals from food.
• Digestion in the stomach that takes 3 to 4 hours & some nutrients and bioactive compounds absorbed.

Functions of the Pancreas, Liver, and Gallbladder

• Pancreas Aids digestion by producing enzyme-rich juices to help break food down in the small intestine and Also regulates balances blood sugar levels by releasing glucagon.

• Liver Processes blood from the stomach and intestines breaking down nutrients that helps in production of bile.

• Liver also regulates blood clotting, stores glucose, and plays a immune function.

• Gallbladder stores andreleases bile and contracts during meals to deliver bile through biliary helps break down dietary fats. These organs that ensures the process of nutrients digestion is efficient.

• The 20 foot small intestine digests food & absorbs nutrients through villi increasing surface area.

• The small intestine is partitioned unto Three sectiles called the duodenum, jejunum, and ileum, it turns food into liquid, aiding nutrient absorption by delivering digestive juices and delivering bile to break down food.

• Lumen of the small intestine is where villi maximize nutrients.

• Absorption: Utilizing villi (finger-like projections) and microvilli (hair-like structures) in its lining to maximize nutrient and water uptake into the bloodstream.

• Waste Transfer Moving remaining waste the large intestine.

• The five foot long large intestine processes indigestible material after the small intestine as well as absorbs most nutrients.

• Large Intestine also includes the cecum, ascending, transverse, descending, and sigmoid colons and the major functions are detailed below.

• Water and Electrolyte Absorption allows it to absorb nutrients key in solidifying stool absorbing water and nutrients.

• Vitamin Production and Absorption happens in the large Intestine as well.

• feces that are eliminated by propulsion via contractions (descending colon)and elimination of water/salts form feces

• The Rectum` and Anus that are the final components of the digestive tract stores and eliminates the final waste.

• Rectum, being a six inch long container in the large intestine helps stores feces before passing it out.

• Anus is where stool exits the body and secretes mucus to elimate for lubrication.

Conclusion

• Nutrition encompases the intake, ingestion, and absorption of nutrients for overall health and well being.
• Plants harness sunlight and require the presence of macro and micro nutrients for metabolic processes.
• Animals relay on plant consumption for food and nutrition
• There are a number if key stage including ingestion, digestion, absorption and elimination.
• Digestion is an the interconected system aided by the small / large intestine, liver, pancreas etc
• Balance diet rich in carbs, protein and minerals are critical for health and over well being.
• Plant and animal nutritional needs are critical for the earth ecosystem with animals relaying on plants for energy.