Life Processes: Nutrition and Photosynthesis

Life Processes

• Vital functions organisms perform to sustain life include nutrition, respiration, transportation, and excretion.

Types of Organisms

• They are either unicellular (single-celled, like Amoeba) or multicellular (many-celled, like humans and plants).

Types of Nutrition - Autotrophic

• Organisms prepare their own food through autotrophic nutrition.
• In photoautotrophic nutrition, photosynthesis is the method.
• Chemoautotrophic nutrition involves using chemicals to produce energy; sulfur bacteria are an example.

Photosynthesis Process

• Carbon dioxide (CO2), water, sunlight, and chlorophyll are required.
• The balanced chemical reaction is 6CO2 + 6H2O → C6H12O6 + 6O2.
• Plants store glucose as starch, while animals store it as glycogen.
• Light energy absorption by chlorophyll is followed by its conversion into chemical energy.
• Water molecules split into hydrogen and oxygen; carbon dioxide reduces to form carbohydrates.

Stomata in Plants

• Leaves have tiny openings called stomata, essential for gas exchange.
• Stomata facilitate transpiration, which removes excess water as vapor, and allow gas exchange during photosynthesis.
• Guard cells manage the opening and closing of stomata.
• When water enters guard cells, they swell, opening the stomata.

Photosynthesis in Desert Plants

• These plants capture sunlight during the day, converting it into chemical energy, and open stomata at night to take in carbon dioxide due to extreme daytime heat.

Types of Nutrition - Heterotrophic

• Organisms depend on others for food
• The three forms are holozoic, saprophytic, and parasitic.
• Holozoic nutrition involves ingesting solid organic matter, digesting it, and absorbing it internally.
• Saprophytic nutrition involves organisms digesting food externally before absorbing nutrients; bacteria and fungi are examples.
• Parasitic nutrition involves organisms obtaining food from other living organisms; lice and Cuscuta (dodder), a plant lacking chlorophyll, are examples.

Stages of Nutrition

• Consists of ingestion, digestion, absorption, assimilation, and egestion.

Nutrition in Amoeba

• Amoeba is unicellular
• Ingestion occurs when the amoeba engulfs a food particle.
• Digestion is the breakdown of food.
• Absorption is the uptake of nutrients.
• Assimilation is the utilization of nutrients for growth and repair.
• Egestion expels undigested waste.

Nutrition in Humans

• Consists of the alimentary canal and associated organs.
• The alimentary canal includes the mouth, esophagus, stomach, small intestine, and large intestine.
• Associated organs include the pancreas and liver.

Mouth and Buccal Cavity

• Teeth crush food into smaller particles.
• Saliva mixes with food, breaking down complex sugars (starch) into maltose.
• Saliva contains amylase, converting complex sugars into simpler sugars.

Esophagus

• Muscle contraction and relaxation push food downward through involuntary movements

Stomach

• The stomach uses three components for food digestion.
• Hydrochloric acid (HCl) eliminates bacteria and aids digestion.
• Pepsin aids protein digestion.
• Mucus protects the stomach wall from acids; acidity arises from an imbalance of mucus and HCl.

Liver and Pancreas

• The liver secretes bile juice, stored in the gallbladder, which emulsifies fats and increases alkalinity.
• The pancreas secretes enzymes such as trypsin, lipase, and pancreatic amylase.

Enzymes

• Trypsin aids in protein digestion, lipase breaks down emulsified fats, and pancreatic amylase helps digest carbohydrates.

Small Intestine

• Intestinal juices secreted by the walls complete food digestion.
• Absorption occurs with villi, finger-like structures increasing surface area.
• Blood vessels in the villi absorb and transport digested food to body cells.
• This organ is very long at 5 to 7 meters

Large Intestine

• Water gets absorbed from undigested food.
• Solid waste stores in the rectum and removes via the anus.

Why Herbivores Have Longer Intestines

• They eat plants containing cellulose, which requires a longer, more complex digestion process.

Respiration

• It obtains energy (ATP) from food.
• The equation is C6H12O6 + 6O2 -> 6CO2 + 6H2O + Energy (ATP).
• Glucose breaks down into carbon dioxide, water, and ATP.

Differences between Breathing and Respiration

• Breathing involves inhaling and exhaling, taking in oxygen.
• Respiration uses oxygen for a chemical process extracting energy from food and converting it to ATP.

Types of Respiration

• Aerobic respiration occurs with oxygen, breaking down glucose into carbon dioxide and water.
• Anaerobic respiration occurs without oxygen, breaking down glucose into carbon dioxide, ethanol, and lactic acid.

Glucose Breakdown Process

• Present in the cytoplasm, glucose breaks down into pyruvate.
• With oxygen, in the mitochondria, pyruvate turns into carbon dioxide, water, and energy.
• Without oxygen (in yeast), it turns into ethanol, carbon dioxide, and energy.
• With little oxygen (e.g., in muscles), lactic acid and energy form.

Respiration in Humans

• Air travels through the: nasal cavity -> pharynx -> larynx -> trachea -> bronchi -> bronchioles -> alveoli.
• Gaseous exchange occurs in alveoli, each covered with blood vessels.

Alveoli

• They absorb oxygen from incoming air into red blood cells and emit carbon dioxide.
• Walls facilitate gas exchange, a network of blood vessels help that exchange happen, and red blood cells contain hemoglobin binding oxygen.

Respiration in Fish

• They take in oxygen through gills and have a faster breathing rate because there is less oxygen in the water.

Transportation

• Moves substances from one body part to another, involving blood, blood vessels, and the heart.

Blood

• Blood contains blood plasma and blood corpuscles: red blood cells, white blood cells, and platelets.

RBCs

• Red blood cells contain hemoglobin and supply oxygen.

WBCs

• White blood cells protect against infections

Platelets

• They are for blood clotting
• Important functions include: transporting nutrients to body cells, transporting hormones, maintaining body temperature and pH balance and fluid volume, and preventing blood loss.

Blood Vessels

• Arteries, veins, and capillaries facilitate transfer
• Arteries carry blood away from the heart, veins towards the heart, and capillaries link veins and arteries.

Arteries

• They are thick to withstand blood pressure.

Veins

• They have thin walls due to constant, consistent pressure.

Capillaries

• They have no outer or middle layer.

Oxygenated Blood in Blood Vessels

• Arteries carry oxygenated blood (except for the pulmonary artery).
• Veins usually have non-oxygenated blood (except for the pulmonary vein).

Vein Valves

• Contain valves to prevent backflow
• Arteries do not backflow because of high blood pressure.

Summary of Blood Vessels

• Arteries: Away from heart, oxygenated blood, high pressure, and thick walls.
• Veins: Towards the heart, non-oxygenated blood, low pressure, and thin walls.
• Capillaries: Facilitate exchange.

Human Heart: Circulation

• Requires systemic and pulmonary circuits.
• Blood from the lungs goes to the left atrium, then the left ventricle, and then pumps to arteries, vessels, and organs.
• CO2 blood goes to the right side, the right ventricle, and then to the lungs through the pulmonary artery.

Double Circulation

• It pumps in two cycles, in two chambers.

Chamber Functions

• Chambers separate oxygenated and non-oxygenated blood, supply more O2 to body organs, provide efficient supply, and lead to higher energy.

Lymphatic System

• The system has lymph fluid, vessels, and nodes
• Key elements include balancing/regulating, fat transport/digestion, and improved immune cells.

Transportation - Plants

Xylem

• It carries water and minerals.

Phloem

• Constructs and moves foods.

Direction

• Xylem carries in one direction, Phloem transports in two directions

Living Part

• Deals with dead/non-dead parts.
• Xylem helps regulate temperature and excess water.

Translocation

• Movement is up and down.
• Includes 4 cells that perform functions.

Excretion

Elements

• 2 kidneys
• 2 ureters
• Bladder
• Urethra

Kidney

• It excretes waste, regulates balance and fluid, and produces EPO and BPO

Nephron

• Glomerular filtration, reabsorption, and secretion occur.

Artificial

• Plants excrete O2 and CO2 and transport items to vacuoles for storage.