Understanding Life Processes

• Distinguishing between living and non-living involves observing movement, growth, and breathing
• Visible movement isn't a definitive characteristic of life
• Invisible molecular movement is essential, as seen in the controversy around viruses
• Living organisms maintain and repair their structures due to environmental effects at the molecular level

What are Life Processes?

• Life processes maintain the body, requiring energy
• Life processes collectively perform maintenance
• Energy comes from outside the body via nutrition
• Additional raw material is needed for growth
• Food sources are typically carbon-based molecules
• Varying external energy sources need to be broken down into a uniform energy source
• Chemical reactions, like oxidising-reducing reactions, are essential break down molecules
• Many organisms use oxygen for cellular needs, acquired through respiration
• Single-celled organisms don't need specific organs for intake or removal due to direct environmental contact
• Multi-cellular organisms require specialised tissues for food and oxygen uptake, and waste removal
• A transportation system is needed to carry food and oxygen
• Waste by-products from energy generation need to be removed via excretion

Nutrition

• Nutrition energy is used during activity and to maintain order in the body
• Additional materials are needed for growth
• Food provides energy and materials
• The general requirement for energy is common in all organisms, but it is fulfilled differently
• Autotrophs use simple food material from inorganic sources like CO2 and water
• Autotrophs include green plants and some bacteria
• Heterotrophs utilize complex substances and break them down into simpler ones, organisms use bio-catalysts called enzymes
• Heterotrophic survival depends directly or indirectly on autotrophs
• Animals and fungi are heterotrophs

Autotrophic Nutrition

• Autotrophs fulfil carbon and energy needs through photosynthesis
• Plants convert substances into stored energy using carbon dioxide and water
• The carbohydrates are synthesised in sunlight and chlorophyll
• Carbohydrates are used for energy
• Unused carbohydrates are stored as starch for future use
• Starch is the internal energy reserve used when the plant needs it
• Glycogen in the body operates similarly to starch in plants, where excess energy from consumed food is stored

Process of Photosynthesis

• Light energy is absorbed by chlorophyll
• Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen occurs
• Carbon dioxide is reduced to carbohydrates
• Desert plants intake carbon dioxide at night and use energy absorbed by chlorophyll during the day
• Microscopic observation shows green dots (chloroplasts) within cells, containing chlorophyll
• Stomata are tiny pores for gaseous exchange, and water loss
• Plants close stomata when carbon dioxide is not needed

Plant Raw Materials

• Water for photosynthesis is taken up from the soil by the roots
• Nitrogen, phosphorus, iron, and magnesium are taken up from the soil
• Nitrogen, phosphorus, iron, and magnesium are used to build their bodies
• Nitrogen is essential for synthesizing proteins and other compounds, taken up as inorganic nitrates, nitrites, or organic compounds prepared by bacteria from atmospheric nitrogen

Heterotrophic Nutrition

• Organisms adapt their nutrition to the environment
• The form of nutrition depends on the type and availability of food
• Nutrition also depends on how food is obtained by the organism
• Some organisms break down food outside the body and then absorb it
• Examples are fungi like bread moulds, yeast, and mushrooms
• Others take in whole material and break it down inside their bodies
• What is taken in and broken down depends on the body design and functioning
• Some other organisms derive nutrition from plants or animals without killing them
• This parasitic nutritive strategy is used by a wide variety of organisms

How Organisms Obtain Nutrition

• The digestive system differs based on food and how it's obtained
• Single-celled organisms may take in food by the entire surface
• As complexity increases, different parts become specialised to perform different functions
• Amoeba intakes food using temporary finger-like extensions, forming a food vacuole
• Substances are broken down into simpler ones which then diffuse into the cytoplasm
• Undigested material is moved to the surface and thrown out, through a process called exocytosis
• Paramoecium takes takes food in at a specific spot
• Food is moved to this spot by the movement of cilia which cover the entire surface of the cell

Nutrition in Human Beings

• The alimentary canal is a long tube from mouth to anus
• In human beings, various regions are specialized to perform different functions

Activity of Digestion

• Teeth crush food into small particles making it easy to swallow
• The food is wetted with saliva to make passage smooth
• Salivary glands secrete saliva, containing enzymes, is secreted to break down complex nutrients in food
• Salivary amylase is an enzyme that breaks down starch into simple sugar
• Muscular tongue moves food around the mouth and throat
• Food moves along the digestive tube processed in each part
• Peristaltic movements contract the gut to push food forward
• The food moves from mouth to the stomach via the oesophagus
• Stomach expands to hold the food
• Muscular stomach walls mix food with digestive juices
• Gastric glands release hydrochloric acid to create an acidic environment
• Protein digesting enzyme called pepsin is also released, and mucous is also released
• Mucus protects the lining of the stomach from the acidic environment

Further Digestion

• Sphincter muscles regulate food exit from the stomach into the small intestine
• The small intestine is the longest part of the alimentary canal, fitted into a compact space by extensive coiling
• The length of the small intestine depends on the type of food eaten which cellulose takes longer to digest so herbivores have longer
• Digestion of carbohydrates, proteins and fats is completed in the small intestine along with secretions from the liver and pancreas
• Bile juice from the liver makes the food alkaline and acts on fats
• Bile salts break down fats into smaller globules, a process known as emulsification
• Pancreas contains enzymes like trypsin and lipase for proteins and emulsified fats
• Walls of the small intestine contain glands that secrete intestinal juice, converting proteins to amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol
• Digested food and nutrients are taken up by the walls of the intestine which the inner lining has finger like villi

More on Digestion

• Villi increase surface area for absorption and absorbed food is taken to cells where it is used for energy
• Unabsorbed food moves to the large intestine for water absorption, and the rest of the waste is removed
• Dental caries causes gradual softening of enamel and dentine
• Caries begins when bacteria produces acids that demineralise the enamel
• Masses of bacteria and food particles stick to the teeth to form dental plaque
• Saliva cannot reach the teeth to neutralise the acid
• Plaque can be removed by brushing teeth after eating

Respiration

• Food provides energy, and organisms use different ways to provide the energy
• Breakdown of glucose leads to carbon dioxide and (with or without oxygen)
• The first step is breaking glucose, a six-carbon molecule, into a three-carbon molecule called pyruvate
• Pyruvate is converted into ethanol and carbon dioxide during fermentation in yeast
• In the absence of air it is called anaerobic respiration
• Breakdown of pyruvate using oxygen takes place in the mitochondria (aerobic respiration)
• The release of energy in aerobic respiration is greater than anaerobic

Energy pathways

• Sometimes muscle cells lack oxygen, and another pathway for the breakdown of pyruvate is taken.
• Pyruvate is converted into lactic acid which is also a three-carbon molecule, causing cramps.
• Energy released during cellular respiration synthesises ATP
• Breaking down ATP gives rise to a fixed amount of energy
• Aerobic organisms intake sufficient oxygen through stomata

ATP

• ATP is the energy currency
• Energy released during respiration makes ATP from ADP and inorganic phosphate
• Endothermic processes use ATP with the terminal phosphate linkage in ATP being broken using water, the energy equivalent to 30.5 kJ/mol is released
• ATP is used in the cells for the contraction of muscles, protein synthesis, conduction of nervous impulses etc.

Gas Exchange

• Plants exchange gases through stomata and large inter-cellular spaces
• The direction of diffusion depends upon environmental conditions and plant needs
• Animals evolved different organs for the uptake of oxygen and for getting rid of carbon dioxide
• Terrestrial animals breathe the O₂ in the atmosphere
• Animals that live in water need to use the O₂ dissolved in water
• Since the amount of dissolved oxygen is fairly low compared to the amount of oxygen in the air, the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms

Respiration

• Terrestrial organisms use O₂ in atmosphere for respiration
• Oxygen is then absorbed by different organs
• In human beings, air passes through the nostrils, filtered and lined with mucus
• Rings of cartilage are present in the throat to ensure the air-passage doesn't collapse
• The passage divides into smaller tubes in the lungs that terminate in balloon-like structures celled alveoli which contain blood vessels

Alveoli and Breathing

• Alveoli provide a surface where gas exchange occurs which our lungs lift our ribs, flatten diaphragm, and increase chest cavity
• Lungs contain a residual volume of air, so there is sufficient time for gas absorption/release
• Respiratory pigments uptake O₂ in lungs and carry it tissues deficient in O₂ before releasing it (haemoglobin) which is present in red blood corpuscles
• Carbon dioxide is soluble in water, so it goes through the blood as a dissolved substance
• Using tobacco directly or any product of tobacco affects speech, heart and organs

Transportation

• Blood transports food, oxygen, and waste materials
• Blood consists of a fluid medium called plasma where cells are suspended
• Liquid plasma transports food, carbon dioxide, and nitrogenous wastes in dissolved form
• Oxygen is carried by red blood corpuscles, and other substances (like salts) go to cells
• Body needs a pumping organ (heart) so blood can reach all the tissues
• A network of tubes (blood vessels) is needed to reach the cells
• A system is vital to repair damage

The Heart and Blood

• The heart is the muscular pump that is as big as a fist. Blood is split into compartments that keeps the oxygen and carbon dioxide separate
• Blood vessels transport O₂ and CO₂, and it needs to reach the tissues so it can function
• Blood passes through two chambers, the atria and right ventricle
• Oxygen-rich blood pumps into left atrium from the lungs
• Blood moves through left and right chambers
• Valves ensure blood doesn't flow backward Oxygen in the blood
• Separation of oxygenated and de-oxygenated blood assists with oxygen supply to birds and mammals because they need energy
• Animals that do not use energy depend on temp for body temperature
• Fishes only travel through the heart once and travels into the body
• Double circulation is twice during others.

Blood Pressure

• The force that blood exerts agains wall is pressure
• Pressure is more arterial. Systolic blood pressure and diastolic
• High blood pressure is caused when contraction. Arterioles construct

Tubes and Blood Vessels

• Arteries in the vessels has to carry blood away from organs
• Arches have vessels from high pressure
• Valves ensure that it goes one side
• Artery divides into smaller and blood vessels contacts all for cells
• Vessels divide by cellular cells called capillaries
• Substances exchange on vessels
• Leakages is known as the platelet vessels that leaks because of blood losses to the system

Plant Transportation

• Blood has platelet cells to make sure blood circulates. Lymph
• Fluid involves transportation. Plasma with proteins escape through interspaces to form fluid
• Extra fluids go to the lymph vessels
• Lymph digest vessels to cells fat to flood

Water and Minerals

• Plants use inorganic and chlorophyll to store their energy. Others for building other plant bodies. Absorbed through rocks for nutrients
• Water for soil and chlorophyll with easily produce water
• When distant in material, they will not have to produce enough energy in plants
• Plants have low energy to make slow systems and work properly
• Move stores for energy, zyle, pholem to other cells to store nutrients

More on Water and Minerals

• Connects water in leaves
• Roots take place from 2 ions
• Move water in root zones.
• Suction for leaves to create water and transpiration with stems

Transportation

• Transpiration pulls mineral from stems to tissues
• Plant need water at night. Stomata helps with transportation of water/minerals from stems to leaves.
• Plants photosynthesise food to other structures.
• Vasilar transports photosyntesis. Also pholem transports substances that carry products.
• Pholem transports amino acids. The root moves things to stems, fruits, and tissues to help them grow
• Translocation happens at companion in all directions.
• Pholem Utilises energy form sugar

Excretion

• Organism gets rid of organic material or gas
• By organic for removal or substance
• Cells diffuse the bad things by cells
• Use surface water to move the energy
• In human beings it removes the kidneys, and urethra

More on Excretion

• Kidney passes for the others
• Urine is to release toxins
• Nitrogen waste from energy
• The cluster helps make blood
• Cluster is kidney is called to the Bowman substance
• Reabsorped for the liquid and for water
• Under nervous for urge to release

Artificial Kidneys

• Artificial kidneys provide aid because of infections of kidney activity
• Remove nitrogen for all the energy
• The pressure helps make vessel to become more stronger
• Tissues and leaves can be lost
• Vacucles can store energy for cell. Energy waste for leaves. Roots can move with nitrogen with wastes.