Biology: definitions

• Mast cell


  Involved with the inflammatory response, triggers the release of histamine and serotonin in response to perceived threat
• Mast cells


  • Not found in blood circulation, found stationary in the tissues
• Inflammatory response


  Produces histamine
• Phagocytes


  White blood cells produced continuously in the bone marrow, responsible for removing dead cells and invasive microorganisms by phagocytosis and engulfing them and digesting them with their hydrolytic enzymes
• Types of phagocytes


  • Neutrophils
  • Macrophages
• Neutrophils


  • Travel throughout the body and often leave the body by squeezing through the capillary walls to patrol the body tissues during infection, released in large numbers from their stores, quite short-lived
• Macrophages


  • Larger than neutrophils, long-lived cells, move into organs like the lungs, liver, spleen, kidney and lymph nodes
• Basophils


  Similar to mast cells except they circulate in the bloodstream, release histamine in the inflammation response in response to an allergen, release heparin to prevent unnecessary blood clotting, release serotonin which makes capillary walls more leaky during infection
• Eosinophils


  Can carry out phagocytosis but they specialize in the destruction of parasites like parasitic worms, involved in counteracting the inflammation response
• Natural killer cells


  Constantly patrol the body searching for abnormal cells which may have been infected with a virus or mutated with the possibility of becoming cancerous, will immediately kill any abnormal cell it finds, not selective about their target
• Blood group types


  • A (I^A I^A or I^A I)
  • B (I^B I^B or I^B I)
  • AB (I^A I^B)
  • O (I I)
• A and B blood groups are co-dominant, O is recessive
• Glycolysis


  turns 1 glucose into 2 pyruvate. phosphate from hydrolysis of atp added to glucose. when 1 phosphate added, glucose phosphate formed. when 2 phosphate added, hexose phosphate is fromed. Hexose biphosphate splits into 2, forming triose phosphate (3c sugar and 1 phosphate group). both Triose phosphates are dehydrogenatedz removing 2 hydrogen each. hydrogen is combined with coenzyme NAD, which forms reduced NAD. 2 atp are formed from substrate level phosphorylation. pyruvate is formed
• Link reaction


  Pyruvate is taken from the cytoplasm after glycolysis and is actively transported into mitochondrial matrix. Pyruvate is dehydrogenated and decarboxylated. This from acetate. Acetate forms actilecoenzyme a when combined with Coenzyme a. Hydrogen from Pyruvate is combined with NAD to form reduced NAD
• How is ATP synthesized?

  ADP is combined with one phosphate (pi) by condensation reaction to form atp. happens with enzyme ATP synthase.

  ADP + pi---> ATP
• How is ATP used to produce energy?

  A phosphate bond in ATP is broken, releasing energy. Bond is broken by hydrolysis.

  ATP---> pi +ADP + energy
• Structure of ATP


  - Three joint phosphate molecules.

  - ribose attached to phosphate

  -Adenine attached to phosphate
• Describe resting potential


  -cell is polarised

  - More negative inside than outside

  - sodium and potassium channels are closed

  - sodium-potassium pump brings 3 sodium out and 2 potassium in.

  -Resting potential is at -70mV
• Describe action potential


  - Cell is depolarised

  - inside is more positive than outside

  - potential goes from -70mV, to +30mV

  - sodium channels open, sodium enters and caused impulse
• Describe repolarisation


  - sodium channels close

  - Potassium channels open

  - inside becomes negative again, repolarised

  - Potassium channels close, very slow, so too much potassium moves out of cell

  - inside cell becomes too negative (hyperpolarised)

  - sodium-Potassium pump repolarises cell again by taking out 3 sodium and pumping in 2 potassium.

  ​
• Krebs cycle


  Acetylecoenzyme A is 2c compound, combines with 4c compound to make 6c compound. Coenzyme A reused in link reaction to collect more acetate.

  6c compound turned into 5c, then 4c compound. Done by dehydrogenation (loses 8H) and decarboxylation (loses 2co²)

  3 pairs of H combine with NAD to form 3 reduced NAD.

  1 pair on H combines with FAD to form 1 reduced FAD.

  1 ATP molecule made with each turn of the cycle.
• Oxidative phosphorylation


  Takes place in mitochondrial cristae.

  Reduced FAD and NAD from krebs cycle, release protons and electrons. NAD and FAD are reused in glycolysis/link reaction/krebs cycle

  Electrons pass down ETCwhich releases H. Energy is used to pump protons/H into inner membrane. But it is impermeable which causes a build up, and a gradient. H diffuses down the gradient into ATP synthase enzymes and into the matrix.

  Flow of H is called proton motor force. Causes energy to be released which is used to combine ADP with phosphate. Oxygen combined with protons and electrons to form H2O.
• Sources of carbs, protein, lipids, vitamins, minerals, water and fibre

  Bread, rice, pasta

  Fish, eggs, beans, meat

  Butter, oil, seeds, nut

  Fruit, vegetables, fortified cereal

  Meat, cheese, milk, fruit, vegetables

  Water, soup

  Whole grain foods, raw vegetables
• Role of carbs, protein, lipid, vitamins, minerals, water, fibre

  Carbs- Main energy source

  Protein- Growth and repair

  Lipid- Energy reserve, nerve impulses, cussions organs

  Vitamins- fights infection, regulates hormones, heals wounds

  Minerals- regulate water balance, nerve function, building bone materials

  Water- removes waste, bowel movement,

  Fibre- Digestion
• Mouth


  food is chewed and mixed with saliva (mechanical and chemical digestion)
• Oesophagus


  Tube connecting the mouth to the stomach
• Stomach


  large muscular sac that continues the mechanical (stomach contracts) and chemical digestion (acid and enzymes: pepsin/protease enzymes) of food
• Liver


  produces bile which emulsifies fat and neutralizes acid
• Gal bladder


  stores bile salts produced by liver
• Pancreas


  Produces enzymes to neutralize acid. Also produces insulin
• small intestine


  Tube containing Duodenum and ileum which completes digestion and absorbs nutrients from food.
• large intestine


  Lpng tube that absorbs water and forms feces
• Rectum


  Stores feces till it leaves body through anus
• Duodenum


  Begins breaking down nutrients to be absorbed
• Iluem


  Has folds (villi) to increase surface area for digestion and absorption
• Carb digestion, amylase


  Salivary amylase, starch substrate, produces maltose, enzyme secreted through saliva in mouth, takes place in neutral conditions

  Pancreatic amylase- Starch substrate, produces maltose, secreted from Pancreas into Duodenum, tales place in alkaline conditions
• Carb digestion, maltase


  Substrate is maltose, produces alpha glucose. Enzyme secreted in ileum. Enzyme works at alkaline conditions. Maltose is broken down by maltase (from ileum) to form Alpha-glucose
• Protein digestion, pepsin


  Protein broken down by pepsin to form smaller polypeptides. Pepsin in stomach, needs acidic conditions (PH 2)
• Protein digestion, Trypsin


  Trypsin breaks small polypeptides to form dipeptides. Trypsin produced in Pancreas, to Duodenum. Requires alkaline conditions
• Protein digestion, dipeptidases


  Dipeptidases break dibeptides to form amino acids. Enzyme is in ileum. works in alkaline conditions