Life Processes: Nutrition

• LIFE PROCESSES are essential functions organisms perform to maintain life
• Nutrition is the process of obtaining and utilizing food
• Respiration is breaking down food to obtain energy
• Transportation transfers substances from one part of the body to another
• Excretion removes waste materials produced in cells

NUTRITION

• Autotrophic nutrition involves organisms making their own food from simple inorganic materials
• Green plants and autotrophic bacteria are examples
• Heterotrophic nutrition involves organisms that cannot make their own food
• They depend on other organisms for food
• Holozoic nutrition involves consuming and internally digesting complex organic food substances
• Human beings, dogs, cats, and amoeba are examples
• Saprophytic nutrition involves organisms feeding on dead and decaying organic matter
• Fungi, bread molds, yeast, and mushrooms are examples
• Parasitic nutrition involves organisms deriving nutrition from another living organism (host), often harming it
• Lice, leeches, tapeworms, and Cuscuta are examples

PHOTOSYNTHESIS

• Photosynthesis is the process by which plants make their own food from carbon dioxide and water using sunlight energy in the presence of chlorophyll
• Sunlight, carbon dioxide, chlorophyll, and water are the necessary conditions for photosynthesis
• 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6H₂O + 6O₂ is the balanced chemical equation
• Chloroplasts are the site of photosynthesis
• Chlorophyll is present in chloroplasts inside plant cells
• Leaves are green because they contain chloroplasts
• Stomata are tiny pores on the surface of leaves where CO₂ enters
• Guard cells regulate the opening and closing of stomata
• Water is taken up by roots from soil
• Nitrogen, phosphorus, magnesium, and iron are also taken up by roots
• Nitrogen is taken up in the form of nitrates and nitrites
• Food is stored as starch in plants and as glycogen in animals

NUTRITION IN AMOEBA

• An amoeba is a unicellular organism with holozoic nutrition
• It does not have a fixed shape, it uses pseudopodia to ingest food
• Complex substances are broken down into simpler substances in food vacuoles
• Digested food is absorbed in cytoplasm by diffusion
• Undigested food is moved to the cell surface and thrown out

NUTRITION IN PARAMECIUM

• A paramecium is a unicellular organism with a definite shape
• Food is moved to a specific spot by the movement of cilia

NUTRITION IN HUMAN BEINGS

• The alimentary canal is a long tube from the mouth to the anus
• Teeth crush and cut food into small pieces
• Salivary glands secrete saliva containing salivary amylase, which breaks down starch into simple sugars
• Food is pushed into the stomach through the oesophagus by peristaltic movements
• Gastric glands in the stomach create an acidic medium using hydrochloric acid
• Small intestine receives secretions from the liver and pancreas and is the site where fats are emulsified into smaller globules for digestion
• Herbivores have longer small intestines for cellulose digestion, while carnivores have shorter ones because meat is easier to digest

RESPIRATION

• Respiration is the process of releasing energy from food
• Breathing is the physical process of inhaling and exhaling air; energy is not released
• Respiration is a chemical process where food is broken down to produce energy in the form of ATP
• Breathing happens in the lungs; respiration occurs in cells

TYPES OF RESPIRATION

• In cytoplasm, glucose is converted to pyruvate
• Aerobic respiration requires oxygen, produces more energy, and results in complete glucose oxidation and breakdown
• Carbon dioxide and water are the end products, usually occurs in the mitochondria
• Anaerobic respiration does not require oxygen, produces less energy, and results in incomplete glucose oxidation and breakdown
• Carbon dioxide and ethanol or lactic acid are the end products and occurs only in cytoplasm
• Alcoholic fermentation occurs in yeast producing ethanol and carbon dioxide if there's an absence of oxygen
• Lactic acid fermentation happens in our muscle cells and produces lactic acid ,when there's a lack of oxygen
• The buildup of lactic acid in muscles during sudden activity causes cramps

RESPIRATORY SYSTEM IN HUMANS

• Air enters through the nostrils into the nasal passage, which is lined with mucus and hairs for filtration
• The pharynx is a common passage for food and air
• the larynx produces sound and contains vocal cords
• The trachea (windpipe) is supported by rings of cartilage to prevent collapse
• the bronchi connect the trachea to each lung then divides into smaller tubes called bronchioles
• Alveoli are small air sacs in the lungs where exchange of O₂ and CO₂ occurs

CIRCULATION

• The diaphragm is a large, dome-shaped muscle that separates the chest from the abdomen
• Residual volume is the amount of air always remaining in lungs to facilitate gas exchange
• Haemoglobin is a pigment in red blood cells that carries oxygen
• Inhalation involves diaphragm contraction and downward movement, enlargement of the chest cavity, and sucking air into the lungs
• Exhalation involves diaphragm relaxation, upward movement, reduction of the chest cavity, and pushing air out of the lungs

RESPIRATION IN PLANTS

• Exchange of gases occurs through stomata
• Photosynthesis produces oxygen, which is used in respiration, resulting in net O₂ output during the daytime
• Respiration produces carbon dioxide, resulting in net CO₂ output during the night time

CIRCULATORY SYSTEM

• Arteries carry oxygenated blood away from the heart
• Veins carry deoxygenated blood to the heart
• The pulmonary artery carries deoxygenated blood
• The pulmonary vein carries oxygenated blood
• Capillaries help in the exchange of blood

THE HEART

• The heart is a muscular organ with four chambers: right atrium, right ventricle, left atrium, and left ventricle
• The septum separates the heart's chambers and prevents mixing of oxygenated and deoxygenated blood
• Ventricles have thicker walls than atria to withstand high blood pressure
• The vena cava takes deoxygenated blood to the right atrium
• Aorta distributes oxygenated blood to the body from the left ventricle
• Valves are present in veins to prevent backflow of blood
• Birds and mammals have 4 chamber hearts and complete double circulation and are warm blooded
• Amphibians and reptiles have 3 chamber hearts and partial double circulation and are cold blooded
• Fish have 2 chamber hearts and single circulation and are cold blooded
• Blood passes only once through the heart in a complete cycle

COMPONENTS OF BLOOD

• Red blood cells (RBCs) contain haemoglobin and transport oxygen
• White blood cells (WBCs) fight infections and produce antibodies
• Platelets are responsible for blood clotting
• Plasma is the fluid medium that transports food, carbon dioxide, and nitrogenous waste

THE LYMPHATIC SYSTEM

• Lymph is a part of the lymphatic system
• It is formed from leaked components of blood through pores in capillary walls
• Lymph is a colourless fluid containing less protein than blood
• it carries digested and absorbed fat from the intestine
• Drains excess fluid back into the blood.

TRANSPORTATION IN PLANTS

• Xylem transports water and minerals unidirectionally upwards using physical forces
• Phloem transports food, amino acids, and other substances bidirectionally using active transport
• Plants have low energy needs and use slow transport systems because they do not move and have a large proportion of dead cells in many tissues
• Transportation distance can be very large
• Water from soil moves into roots by root pressure, which creates a difference in the concentration of ions
• Transpiration is the loss of water in the form of vapor which helps in absorption and upward movement of water and minerals + temperature regulation

TRANSLOCATION

• The tansfer of food from leaves to other parts of plnt is called translocation
• Phloem traslocates the food made in leaves for delivery to other parts of the plants such as fruits, seeds, and roots.

EXCRETION IN HUMANS

• Excretion is the removal of harmful metabolic wastes from the body
• The excretory system includes the kidneys, ureters, urinary bladder, and urethra
• Kidneys remove nitrogenous waste, such as urea and uric acid, from the blood
• Ureters connect the kidneys with the urinary bladder
• The urinary bladder stores urine and is under nervous control
• The urethra transports urine out of the body
• Nephrons are the structural and functional units of the kidneys, they filters the blood

THE NEPHRON

• The glomerulus is a cluster of blood vessels inside the kidneys
• Bowman's capsule surrounds the glomerulus and collects the filtrate
• Glomerular filtration filters nitrogenous wastes, glucose, water, amino acids, and excessive salts from the blood
• Selective reabsorption reabsorbs essential substances from the filtrate
• Tubular secretion releases urea, extra water, and salts into the tubule
• The amount of water reabsorbed depends on excess amount of water in the body and amount of dissolved waste

ARTIFICIAL KIDNEY

• Used incase of kidney failure
• Removes nitrogenous waste using dialysis
• Uses dialysing solution rich in urea and excess salts to extract them
• Unlike kidney ,has no reabsorption

EXCRETION IN PLANTS

• Oxygen and carbon dioxide diffuse through stomata
• Excess water is removed by transpiration
• Shedding of old leaves and bark
• Plants also secrete some wastes into surrounding soil