biology

• due to the presence of calcium ions, thrombokinase converts prothrombin to insoluble fibrin threads to form a fibrin mesh which creates a scab
• platelets are involved in the formation of a blood clot as they stick to the damaged area of the vessel wall and release chemicals that attract more platelets to the site of injury
• after smoking, toxic substances is breathed in and into the lungs. Mucus is then secreted to catch these substances which is supposed to be sweeped away by the cilia cell. However the toxic substance that was breathed in cause the cilia cell and the epithelium to be paralysed. Thus, the mucus is then remained on the epithelium which creates a blockage from the airway which makes it difficult to breathe.
• the main function of the respiratory system is gas exchange between the body tissues and the external environment
• deamination is the process by which amino groups are removed from amino acids and converted to urea
• hepatic portal vein- Transport blood rich in glucose and amino acids from small intestine to liver
• urea is produced during deamination
• assimilation is the process where some of the absorbed food substances are converted into new cytoplasm or used to provide energy
• emulsification is the breaking down of fats into tiny fat droplets
• digestion is the process where food molecules are broken down into smaller soluble molecules that can be absorbed into the body cells
• aerobic respiration:

  oxygen + glucose -> carbon dioxide + large amt of energy

  anaerobic respiration:

  glucose -> lactic acid + small amt of energy
• ingestion -> digestion -> absorption -> assimilation -> egestion
• wilting occurs when the rate of transpiration exceeds the rate of water absorption by the roots, plant cells lose their turgidity and the whole plant wilts
• transpiration refers to the loss of water vapour from the aerial parts of a plant, especially through the stomata on the underside of leaf.
• Deamination is the process by which amino groups are removed from amino acids and converted to urea which will will be released thru urine
• denaturation is the change in the three dimensional structure of an enzyme or any other soluble proteins, cause by heat or chemicals such as alkali or acids
• catalyst is a substance that can speeds up chemical reaction, without itself being chemically changes at the end of the reaction.
• Enzymes are proteins that function as biological catalysts. They catalyse or speeds up rate of chemical reactions. They remain chemically unchanged at the end of the reaction
• enzymes have specific active sites where substrates bind to them
• substrate is the reactant molecule that combines with an enzyme to form an enzyme-substrate complex
• the shape of the active site determines what type of substrate it can combine with
• active site is the part of an enzyme where the substrate binds to it
• lock and key model states that the shape of the active site matches exactly with the shape of the substrate
• an enzyme has one active site but many substrate binding sites
• lock and key model - enzyme has a fixed structure which fits perfectly with its substrate
• plant cells contains nucleus, cell membrane, cytoplasm, big singular vacuole, chloroplast, cell wall, mitochondrion, and ribosomes
• animal cells contain nucleus, cell membrane, cytoplasm, small but many vacuole, mitochondrion, and ribosomes
• nucleus controls all cell activities
• cell membrane separates inside from outside
• cytoplasm is where chemical reactions take place
• vacuoles store water, waste products, pigments, and food
• vacuoles are used to store water or waste products
• mitochondria produces energy through respiration
• ribosome makes proteins
• mitochondria are the powerhouse of the cell
• chromatin is made up of DNA and protein
• mitochondria produce energy through respiration
• chloroplasts produce glucose during photosynthesis
• plant cells have cell wall made up of cellulose which gives them support and strength
• ribosomes make proteins