Life Processes and Nutrition

Life Processes

• Life processes are all the processes necessary for a living organism to survive, including:
  • Nutrition
  • Respiration
  • Transportation/Circulation
  • Excretion

Nutrition

• Nutrition is the process of obtaining food and utilizing the energy from it
• Two types of nutrition:
  • Autotrophic: Organisms produce their own food, such as plants
  • Heterotrophic: Organisms depend on other organisms for food, such as humans
• Types of heterotrophic nutrition:
  • Holozoic: Organisms consume solid food and digest it inside their body (humans)
  • Saprophytic: Organisms feed on dead and decaying matter and digest it externally (bread mold, mushroom, yeast)
  • Parasitic: Organisms derive nutrition from a host without killing them (tapeworm, lice)
• Plants obtain nutrition through photosynthesis, where carbon dioxide and water are converted to glucose and oxygen using sunlight and chlorophyll.
• Plants store energy as starch; humans store energy as glycogen.

Photosynthesis

• Photosynthesis has three main stages:
  • Absorption of light energy by chlorophyll
  • Converting light energy into chemical energy and splitting water molecules
  • Reducing carbon dioxide to carbohydrates

Guard Cells

• Guard cells are bean-shaped cells controlling the opening and closing of stomata on plant leaves.
• When guard cells gain water, they swell and open stomata.
• When guard cells lose water, they shrink and close stomata.
• Stomata allow for gas exchange in plants.

Amoeba Nutrition

• Amoeba demonstrates holozoic nutrition with five steps:
  • Ingestion: Taking food into the body
  • Digestion: Breaking down food inside the body
  • Absorption: Taking in digested nutrients
  • Assimilation: Utilizing digested nutrients
  • Egestion: Removing waste products

Human Nutrition

• Digestion begins in the mouth with teeth crushing food.
• Saliva contains salivary amylase breaking down complex sugars to simpler sugars (maltose).
• Food moves from the mouth to the esophagus through peristaltic movements.
• The esophagus delivers food to the stomach, a J-shaped organ for chemical digestion.
• Stomach components:
  • Hydrochloric acid: Acidifies food
  • Mucus: Protects stomach walls
  • Pepsin: Breaks down protein
• Food leaves the stomach, entering the small intestine after passing the liver and pancreas.
• Liver secretes bile juice, stored in the gallbladder.
• Bile's functions:
  • Emulsifying fats: Breaking fats into smaller droplets
  • Making food alkaline
• Pancreas secretes pancreatic juice with these enzymes:
  • Trypsin: Digests proteins
  • Lipase: Digests fats
  • Pancreatic amylase: Digests carbohydrates
• Final digestion in the small intestine, nutrients absorbed into the bloodstream through villi.
• Small intestine, also called the "small don," is 5-7 meters long.
• Large intestine absorbs water and eliminates waste through the anus.

Respiration

• Respiration differs from breathing. Breathing is the physical process of inhaling and exhaling oxygen. Respiration is the biochemical breakdown of food (glucose) within cells, using oxygen to release energy.
• Respiration occurs in every body cell.
• Types of respiration:
  • Aerobic: Respiration requiring oxygen.
  • Anaerobic: Respiration not requiring oxygen.

Aerobic vs Anaerobic Respiration

Human Respiratory System

• Respiratory system organs:
  • Nasal passage: Air entry point
  • Pharynx: Passageway for food and air
  • Larynx: Voice box
  • Trachea: Windpipe
  • Bronchi: Two tubes branching from the trachea
  • Bronchioles: Small tubes branching from bronchi
  • Alveoli: Tiny air sacs at the end of bronchioles for gas exchange
• Rib cage and diaphragm aid breathing.
• The diaphragm is a dome-shaped muscle contracting to flatten during inhalation, relaxing to dome during exhalation.
• During inhalation, the diaphragm contracts, increasing chest cavity volume, pulling air into the lungs. During exhalation, the diaphragm relaxes, decreasing chest cavity volume, expelling air.
• Gas exchange in alveoli:
  • Deoxygenated, carbon dioxide-rich blood in surrounding capillaries.
  • Oxygen from inhaled air diffuses into the blood; carbon dioxide diffuses from the blood to be exhaled.
  • Hemoglobin in red blood cells binds oxygen.

Transportation/Circulation

• Transportation is the movement of substances within the body, using blood, blood vessels, and the heart.
• Blood contains:
  • Plasma (water)
  • Platelets: Blood clotting
  • Blood cells:
    • Red blood cells (RBCs): Transport oxygen
    • White blood cells (WBCs): Fight infection, maintain immunity
• Blood vessels:
  • Arteries: Carry blood away from the heart
  • Veins: Carry blood towards the heart
  • Capillaries: Connect arteries and veins, forming a network
• Exceptions:
  • Pulmonary artery: Carries deoxygenated blood from the heart to the lungs.
  • Pulmonary vein: Carries oxygenated blood from the lungs to the heart.
• Arteries have thicker walls to withstand higher blood pressure; veins have valves preventing backflow.
• Heart chambers:
  • Two atria (thin walls, less forceful pumping)
  • Two ventricles (thick walls, stronger pumping)
  • Septum separates right and left sides, preventing blood mixing.

Heart Circulation

• Complete circulatory system with two circuits:
  • Pulmonary circuit: Blood to lungs and back to the heart, picking up oxygen and releasing carbon dioxide.
  • Systemic circuit: Blood to the rest of the body and back to the heart, delivering oxygen and collecting carbon dioxide.
• Oxygenated blood flows back to the heart, then to the rest of the body, collecting carbon dioxide, before returning to the heart to start the cycle again.

Importance of Double Circulation

• Double circulation prevents mixing of oxygenated and deoxygenated blood, leading to more efficient oxygen delivery.

Transportation in Plants

• Plants transport water and nutrients using vascular tissues:
  • Xylem: Transports water and minerals up from roots
  • Phloem: Transports food (sugars) throughout the plant, from leaves to needed areas.
• Xylem flow is unidirectional (upwards); phloem flow is bi-directional, as needed for sugar transport.
• Xylem cells are mostly dead; phloem cells are mainly living.

Excretion

• Excretion removes waste from the body.
• Excretory organs:
  • Kidneys: Filter wastes from blood, producing urine
  • Lungs: Exhale carbon dioxide
  • Skin: Expels sweat (salts and excess water)
  • Liver: Produces bile, breaking down fats and eliminating waste.

Human Excretory System

• The excretory system removes nitrogenous waste, excess water, and other waste from the body.
• Kidneys filter blood and produce urine.
• Bean-shaped kidneys; renal artery brings blood for filtering, renal vein carries filtered blood away.
• Urine travels from kidneys through ureters to urinary bladder, then expelled through the urethra.

Excretion in Humans

• The body filters blood through kidneys
• Waste products are collected in the urinary bladder
• The bladder stores urine until it is excreted through the urethra

The Nephron

• Nephrons are the functional units of the kidneys (millions per kidney)
• Blood filtration, nutrient reabsorption, and waste collection happen in the nephron.
• Three stages of urine formation:
  • Glomerular filtration
  • Selective reabsorption
  • Tubular secretion

Excretion in Plants

• Plants release oxygen during photosynthesis.
• Excess water is released through transpiration from leaves.
• Waste products are stored in roots and stems.
• Some plants secrete gums and resins (used in rubber manufacturing).

Explore the essential life processes that sustain living organisms, focusing on nutrition. Understand the differences between autotrophic and heterotrophic nutrition, including various types such as holozoic, saprophytic, and parasitic. This quiz delves into how plants obtain nutrition through photosynthesis and the implications for various life forms.