Life Processes: Nutrition

• Life processes are essential for survival.
• This chapter will cover nutrition, respiration, transportation, and excretion.

Nutrition

• Nutrition is the process of obtaining food and utilizing its energy.
• Two types of nutrition: autotrophic and heterotrophic

Autotrophic Nutrition

• Organisms that make their own food, like plants.

Heterotrophic Nutrition

• Organisms that depend on others for nutrition, like humans.
• Three types of heterotrophic nutrition: holozoic, saprophytic, and parasitic.

Holozoic Nutrition

• Organisms ingest solid food and digest it internally; humans follow this.

Saprophytic Nutrition

• Organisms feed on dead and decaying matter, digesting food externally.
  • Examples include bread mold, mushrooms, and yeast.

Parasitic Nutrition

• Organisms derive nutrition from a host without killing it.
  • Examples include tapeworms and lice.

Photosynthesis

• Plants use photosynthesis to produce their own food.
• Key reactants: carbon dioxide, water, chlorophyll, and sunlight.
• Products: glucose, oxygen, and water.
• Plants store energy as starch, while humans store it as glycogen.

Steps of Photosynthesis

• Absorption of light energy by chlorophyll.
• Conversion of light energy into chemical energy and splitting of water molecules.
• Reduction of carbon dioxide to carbohydrates.

Guard Cells

• Guard cells control the opening and closing of stomata.
• Stomata regulate gas exchange in plants.
• Stomata open when guard cells have water and close when they don't

Nutrition in Amoeba

• Amoeba follows holozoic nutrition.
• Five steps: ingestion, digestion, absorption, assimilation, and egestion.

Human Digestive System

• Human nutrition involves several organs and enzymes.
• Teeth crush food, and saliva contains salivary amylase which breaks down complex sugars into simpler sugars like maltose.
• The esophagus transports food to the stomach via peristaltic movements.
• The stomach contains hydrochloric acid, mucus, and pepsin, which aids in protein digestion.
• The liver produces bile juice, which is stored in the gallbladder.
• Bile juice emulsifies fats and makes food alkaline.
• The pancreas secretes pancreatic juice, which contains trypsin (breaks down proteins), lipase (breaks down fats), and pancreatic amylase (digests carbohydrates).
• The small intestine, also known as "chota don," is where final digestion occurs.
• Villi in the small intestine absorb digested food into the blood vessels.
• The large intestine absorbs water, and waste is excreted through the anus.

Respiration

• Respiration is the process of burning food in cells with oxygen to release energy.
• Breathing is a physical process involving inhaling and exhaling, while respiration is a biochemical process.
• Breathing occurs in organs like the lungs, while respiration occurs in every cell.

Types of Respiration

• Aerobic respiration: requires oxygen; produces carbon dioxide, water, and energy.
• Anaerobic respiration: does not require oxygen.
  • In the absence of oxygen, glucose is converted into ethanol, carbon dioxide, and energy.
  • With limited oxygen, lactic acid is produced, causing muscle cramps.

Respiratory System

• Air enters through the nasal passage or mouth.
• The pharynx connects the nasal passage to the larynx (voice box).
• Air travels down the trachea, which divides into bronchi.
• Bronchi further divide into bronchioles, which end in alveoli sacs.
• The rib cage protects the lungs, and the diaphragm aids in breathing.
• The diaphragm is curved and flattens when we inhale.

Gas Exchange in Alveoli

• Alveoli are surrounded by blood vessels.
• Oxygen diffuses from the alveoli into the blood, while carbon dioxide diffuses from the blood into the alveoli.
• Hemoglobin in red blood cells carries oxygen and carbon dioxide.
• Hemoglobin has a high affinity for oxygen.

Transportation

• Transportation involves the movement of substances.
• Three main components: blood, blood vessels, and the heart.
• Blood is a fluid containing platelets, plasma, red blood cells, and white blood cells.
  • Platelets aid in blood clotting.
  • Plasma is the fluid part of the blood.
  • Red blood cells contain hemoglobin.
  • White blood cells provide immunity.

Blood Vessels

• Three types of blood vessels: arteries, veins, and capillaries.
• Arteries carry blood away from the heart, usually oxygenated, except for the pulmonary artery.
• Veins carry blood towards the heart, usually deoxygenated, except for the pulmonary vein.
• Capillaries connect arteries and veins.
• Arteries have thick walls to withstand high pressure.
• Veins have thinner walls and contain valves to prevent backflow.

Heart

• The heart pumps blood throughout the body.
• The heart has four chambers: two atria (or auricles) and two ventricles.
• Oxygenated blood from the lungs enters the left atrium via the pulmonary vein, then flows to the left ventricle.
• The aorta carries oxygenated blood to the body.
• Deoxygenated blood from the body enters the right atrium via the vena cava, then flows to the right ventricle.
• The pulmonary artery carries deoxygenated blood to the lungs.
• Atrial walls are thinner than ventricular walls because ventricles need to pump blood with more force.
• The septum separates the left and right sides of the heart.

Double Circulation

• Blood passes through the heart twice in one complete cycle.
• Pulmonary circuit: blood travels from the heart to the lungs and back.
• Systemic circuit: blood travels from the heart to the body and back.
• Double circulation prevents the mixing of oxygenated and deoxygenated blood, allowing for more efficient blood pumping and increased energy.

Transportation in Plants

• Two main components: xylem and phloem.
• Xylem transports water and minerals unidirectionally from the roots to the rest of the plant.
• Phloem transports food bidirectionally throughout the plant.
• Phloem cells are mainly living, while xylem cells are mainly dead.

Excretion in Humans

• Excretion is the removal of waste products from the body.
• The aorta brings blood from the heart, which then divides into renal arteries leading to the kidneys.
• Kidneys filter the blood, and waste products enter the ureters.
• Ureters transport waste to the urinary bladder, where it is stored.
• Urine is excreted through the urethra.

Nephron

• Nephrons are the functional units of the kidney.
• Blood enters the Bowman's capsule for filtration.
• The glomerulus filters out waste products and returns blood to the body.
• Selective reabsorption occurs, where useful substances are reabsorbed into the blood.
• Tubular secretion occurs, where waste products are collected in a tubule.

Steps of the waste process

• Glomerular filtration: initial filtration of blood.
• Selective reabsorption: reabsorption of useful substances into the blood.
• Tubular secretion: collection of waste products in tubules.
• Urine is formed and transported to the urinary bladder for excretion.

Excretion in Plants

• Plants excrete gases, such as oxygen.
• Transpiration releases water.
• Plants release resins and gums.
• Waste can also be excreted into the soil.