Life Processes and Maintenance

• Living beings can be identified by actions like running, chewing cud, or shouting.
• Breathing and growth are also evidence of life, but not always reliable.
• Molecular movement is crucial for life, sparking debate about viruses being alive.
• Living organisms maintain well-organized structures at the molecular level and require constant repair due to environmental effects.

Maintenance Processes

• Maintenance processes are essential to prevent damage and breakdown in organisms.
• Energy and raw materials are required.
• Energy is derived from food, which is the transfer of energy from outside to inside and commonly called nutrition.
• Additional raw materials are needed for growth.

Essential substances

• Life on Earth relies on carbon-based molecules.
• These food sources are usually carbon-based.
• Living things require a uniform energy source for molecular movement, maintaining structures, and growth.
• This involves chemical reactions like oxidising-reducing processes, and is commonly achieved using oxygen from the environment in respiration, to break down food for cellular needs.

Single-celled vs Multi-cellular Organisms

• Single-celled organisms don't need specific organs for food intake, gas exchange, or waste removal because their entire surface is in contact with the environment.
• Multi-cellular organisms need specialized tissues for different functions
• A transportation system is needed to deliver food and oxygen.
• Waste by-products need to be discarded through excretion.

Nutrition Defined

• Energy is needed to maintain order internally, even when not doing anything.
• Materials for growth, development, protein synthesis, and other substances are also needed
• Food consumed fulfills these needs.
• Requirement for energy and materials is universal but fulfilled differently across all organisms.
• Autotrophs uses simple food from inorganic sources like carbon dioxide and water.

Autotrophs vs Heterotrophs

• Autotrophs include green plants and some bacteria.
• Heterotrophs utilize complex substances that are broken down into simpler ones with the help of enzymes.
• Heterotrophic survival depends on autotrophs, heterotrophic organisms includes animals and fungi.
• Autotrophic nutrition is fulfilled by photosynthesis in which carbon dioxide and water are converted into carbohydrates.

Photosynthesis

• Photosynthesis requires sunlight and chlorophyll.
• Carbohydrates provide energy.
• Carbohydrates not used immediately are stored as starch in plants and glycogen in animals for later use.
• Photosynthesis involves the absorption of light energy by chlorophyll.
• Water molecules are split into hydrogen and oxygen.
• Carbon dioxide is reduced to carbohydrates.

Plants' Carbon Dioxide Intake

• Stomata are tiny pores on leaf surfaces.
• Stomata allow for large amounts of gaseous exchange for photosynthesis.
• Gas exchange occurs across stems, roots, and leaves.
• Plants close stomata to prevent water loss when carbon dioxide is unneeded preventing carbon dioxide intake.
• Guard cells control the opening and closing of stomata.
• Guard cells swell with water influx, opening the pore.
• Guard cells shrink, closing the pore.
• Terrestrial plants absorb water and materials from the soil through their roots.
• Nitrogen is critical for synthesizing proteins and other compounds.

Heterotrophic Nutrition

• Organisms adapt based on food type and availability.
• Food sources can be stationary, such as grass, or mobile, such as a deer.
• Nutritive strategies vary between organisms.
• Some break down food outside the body before absorbing it, like fungi.
• Others take in and break down whole materials inside their bodies, others derive nutrition without killing.
• Cuscuta, ticks, lice, leeches, and tapeworms use parasitic nutritive strategies.
• Single-celled organisms may take in food through their entire surface.

Human Digestion

• Humans consume food which go through a centralized digestive tract
• Food must be crushed into smaller particles.
• Saliva aids the digestive system.
• Enzymes break down the complex molecules into simpler ones.
• Saliva contains salivary amylase, which breaks down starch into simple sugar.
• Tongue mixes food with saliva. peristaltic movements push food along the gut.
• From mouth, food travels through oesophagus to stomach.
• Stomach expands to store food.

Stomach Digestion

• Stomach is a large organ.
• Stomach help mix food with juices through the muscular walls .
• Gastric glands in the stomach wall release hydrochloric acid, pepsin, and mucus.
• Hydrochloric acid creates an acidic medium for pepsin.
• Pepsin is a protein-digesting enzyme.
• Mucus protects the stomach lining from the acid.
• A sphincter muscle regulates food exit from the stomach into the small intestine.
• Small intestine is the longest part of the alimentary canal in a compact space.
• The length of the small intestine differs among animals according to diet.

Herbivores vs Carnivores Digestion

• Herbivores need a longer small intestine for cellulose digestion.
• Carnivores have a shorter small intestine as meat is easy to digest.
• Small intestine is the main point for Carbohydrates, proteins and fats digestion.
• Enzymes are in the Pancreas and liver.
• Food from the stomach must be made alkaline for pancreatic enzymes to function.
• Bile juice from the liver aids this process and acts on fats.
• Bile salts break down fat globules, similar to how soaps emulsify dirt.

Key Enzymes

• Pancreas secretes pancreatic juice containing trypsin (for proteins) and lipase (for emulsified fats).
• Intestinal juice contains enzymes that convert proteins to amino acids, carbohydrates to glucose, and fats to fatty acids and glycerol.
• The walls of the small intestine has finger-like projections called villi increasing the surface area for absorption.
• Blood vessels in Villi absorb food to cells in the body.
• Unabsorbed food goes into the large intestine, where water is absorbed.
• Waste is removed via the anus, regulated by the anal sphincter.

Dental Caries

• Dental caries causes gradual softening of enamel and dentine.
• It begins when bacteria produce acids from sugars, softening the enamel creating masses of cells and food particles forming plaque and acid.
• Plaque prevents saliva from neutralizing the acid.
• Bacteria can cause inflammation and infection if left untreated.
• Eating various food types requires digestive processing to generate small particles.
• Saliva helps in crushing food with teeth to pass smoothly in the digestion system.
• The food must be wetted to make it pass smooth.

Respiration

• The first step is the break-down of glucose, a six-carbon molecule, into a three-carbon molecule called pyruvate.
• This process takes place in the cytoplasm.
• The pyruvate may be converted into ethanol and carbon dioxide in fermentation which is called anaerobic respiration.
• Breaking down pyruvate using oxygen occurs in the mitochondria which is called aerobic respiration.
• Aerobic organisms require oxygen intake. Plants exchange gases through stomata.
• Oxygen and carbon dioxide are exchanged by diffusion.

ATP

• ATP is energy used in cellular processes.
• It is made from ADP and inorganic phosphate
• In cellular activity this results in 30.5 kJ/mol of released energy
• Similar to a battery providing energy, ATP is used for muscle contraction, protein synthesis, nerve impulses, etc.
• Plants exchange gases through stomata, and large inter-cellular spaces ensure contact with air.

Animal Respiration

• Animals use evolved organs for oxygen uptake and carbon dioxide removal.
• Terrestrial animals breathe atmospheric oxygen.
• Aquatic animals use dissolved oxygen in water and have faster breathing rates.
• Fish take in water to their gills to absorb oxygen.
• Terrestrial organisms absorb oxygen from their blood.
• Different organs increase surface area for respiration.
• exchange of oxygen and carbon dioxide occurs across surfaces.

Human Respiratory System in Brief

• In human beings, air enters through nostrils, filtered by hairs and mucus.
• Air passes through the throat to the lungs.
• Cartilage rings prevent throat collapse.
• Lungs have smaller tubes ending in balloon-like alveoli where gas exchange occurs.
• Alveoli walls have blood vessels
• During breathing, ribs lift, the diaphragm flattens, and the chest cavity expands filling alveoli.
• Blood transports carbon dioxide to alveoli and oxygen to all cells in the body.
• The lungs maintain a residual volume of air for continuous gas exchange.

Hemoglobin

• Respiratory pigments transport oxygen to tissues.
• Hemoglobin, present in red blood cells, has a high affinity for oxygen.
• Carbon dioxide is more soluble in water and is transported in dissolved form in the blood.

Transportation in the Human Body

• Blood transports food, oxygen, and waste materials.
• Blood is a connective tissue with cells suspended in plasma.
• Plasma transports food, carbon dioxide, and nitrogenous wastes in dissolved form.
• Oxygen is carried by red blood corpuscles.
• A pumping organ that is the Heart is needed to push blood, network of tubes, and a repair system is needed.
• Double circulation goes through the heart twice.

Our Heart

• The heart is a muscular organ .
• Different chambers prevent mixing of oxygen-rich and carbon dioxide-rich blood.
• Carbon dioxide-rich blood goes to the lungs, and oxygenated blood returns to the heart to pump it to the body which can be found in 5.11 figure.
• Oxygen-rich blood flows from the lungs to the left atrium and then to the left ventricle, which pumps it to the body.
• De-oxygenated blood comes from the body to the right atrium and then to the right ventricle, which pumps it to the lungs.
• Valves prevent blood from flowing backwards.
• Separation stops oxygenated and deoxygenated blood from mixing.
• Efficient oxygen supply is useful for animals with high energy needs, like birds and mammals.
• Fish have two-chambered hearts with blood pumped to the gills and then to the body and the fish blood cycle is once.

Blood Pressure

• Force exerted by blood against vessel walls is called blood pressure.
• Pressure is greater in arteries than in veins.
• Systolic pressure is during ventricular contraction.
• Diastolic pressure is during ventricular relaxation.
• Normal systolic pressure is about 120 mm of Hg.
• Normal diastolic pressure is about 80 mm of Hg.
• Blood pressure is measured using sphygmomanometer. High is Hypertension.
• Constriction of arterioles causes hypertension and can cause artery rupture.

The Tubes

• Arteries carry blood from the heart.
• High pressure causes the arteries to have thick, elastic walls.
• Veins collect blood and return it to the heart and do not need thick walls and are not at high pressure and have valves to ensure blood flows in one direction.
• Arteries divides into smaller vessels to bring blood to cells called capillaries.
• Capillaries have one-cell thick walls for exchange of materials.
• Capillaries join to form veins.

Platelets & Lymph

• Platelet cells circulate to clot blood at injury sites.
• Lymph/tissue fluid is another transport fluid that contains blood cells to intracellular.
• Lymph fluid transports material and carries absorbed fat, returning excess fluid to blood.
• They absorb carbon dioxide and photosynthesise.
• They require nitrogen, phosphorus and other materials.
• They get raw materials from their roots.
• Energy needs varies in their body.
• Most plants use dead cells in the form of xylem.
• Xylem transport water and other minerals.
• Pholem transfers materials in their system.

Transport

• Xylem tissue are interconnected and form channels for water conduction.
• Roots absorbs the substance.
• Water moves from the soil.
• Transpiration involves water loss from aerial parts, aiding absorption and movement of water and minerals while helping temperature regulation. This occurs during the day when the stomata are open.

Translocation

• Translocation moves photosynthesis products from leaves to other parts, transports amino acids and other substances.
• It delivers storage for seeds and is moved in a up and down motion.
• Unlike xylem it relies on energy. Sucrose is transferred in phloem.
• Pholoem moves in a more efficient way instead of xylem.

Excretion

• Organisms gets rid of wastes.
• Nitrogenous materials need to be transported.
• This takes place in a process called excretion.
• Many organisms use a diffusion from the body to the water.
• More complexed organisms have special functions and organs.

Human Excretion System

• Humans have a system with Kidneys/Ureters/Urinary bladder.
• The kidneys are next to the backbone
• Kidneys passes through the system through the Ureters
• Then goes to the Urinary .The system releases in the Urethra

Urine Production

• Urine removes waste.
• Carbon dioxide and nitrogenous waste.
• Nephrons are filter units.
• Kidneys are vital organs. and requires dialysis.
• A dialysis removes the wast and filters.
• It has similiar functions except re absorption.
• A healthy adults needs 180 L.

Plants Excretion

• Plants uses many different strategies for excretion than those of animals.
• Transpiration removes water. dead trees and shed leaves.
• Many vacuoules/wax is created.
• The plants excretes some waste into the soil.