organisation

• Cells


  Fundamental units of life, each designed to perform specialised functions through a process called DIFFERENTIATION
• Differentiation


  1. Specialised cells combine to form TISSUES

  2. Tissues group to create ORGANS

  3. Multiple organs work together to form ORGAN SYSTEMS within larger multicellular organisms
• Tissue


  A group of cells with similar structures and function that work together to carry out specific jobs
• Tissues in mammals


  • Muscular tissue: Responsible for movement by contracting and relaxing
  • Glandular tissue: Produces and releases substances like enzymes and hormones
  • Epithelial tissue: Covers the surfaces of the body, such as the inside of the gut
• Organ


  Complex structures composed of different tissues, each contributing to the organ's overall function
• Organ


  • The HEART is an organ that contains muscular tissue for PUMPING BLOOD around the body
• Organ system


  A group of ORGANS working together to perform complex functions for the organism's survival
• Organ system


  • The CIRCULATORY SYSTEM is an example of an organ system
• Enzymes


  BIOLOGICAL CATALYSTS—they speed up reactions without being consumed or altered
• Enzymes are produced by living organisms to regulate chemical reactions
• Enzymes


  Large PROTEINS composed of amino acid chains. These proteins fold into UNIQUE SHAPES that are crucial for their function
• Active site


  Shape that fits substances known as SUBSTRATES
• Enzymes are SPECIFIC which means one type of enzyme will only fit one type of substrate
• Enzyme catalysis


  1. Substrate binds to active site

  2. Substrate breaks up to form products

  3. Specificity ensures precision in biological processes
• Lock and key model

  Explains enzyme specificity, although the more accurate 'INDUCED FIT' model acknowledges that the enzyme's active site changes slightly to secure the substrate
• As temperature increases


  The rate of enzyme controlled reactions increases up to a certain point. This is because the enzyme and substrates move around faster meaning there are MORE COLLISIONS per second.

  • The rate is the fastest at the OPTIMUM TEMPERATURE.
  • As the temperature increases past the optimum, the rate DECREASES. This is because the enzymes DENATURE causing the active site to change shape.
• This is because the enzyme and substrates move around faster meaning there are MORE COLLISIONS per second
• Optimum temperature


  The temperature at which the rate of enzyme controlled reactions is the fastest
• As temperature increases past the optimum

  The rate DECREASES because the enzymes DENATURE causing the active site to change shape
• Optimum pH


  The pH at which enzymes work the best
• As the pH increases or decreases from the optimum

  The rate of enzyme controlled reactions DECREASES because enzymes DENATURE causing the active site to change shape
• Enzyme optimum pH


  • Most enzymes in the human body have an optimum pH of 7, but there are some which have different ones, like PEPSIN which works best in acidic conditions (pH 2) found in the stomach
• • All enzymes have an OPTIMUM pH that they work the best in
  • As the pH increases or decreases from the optimum, the rate of reaction DECREASES. This is because enzymes DENATURE causing the active site to change shape.
  • Most enzymes in the human body have an optimum pH of 7, but there are some which have different ones.
  • The enzyme PEPSIN, for instance, works best in acidic conditions (pH 2) found in the stomach, which shows the importance of the optimum pH for enzyme activity.
• • DIGESTIVE ENZYMES are crucial in breaking down large molecules like STARCH, PROTEINS, and FATS into smaller, soluble molecules. This allows them to be absorbed into the bloodstream.
• • CARBOHYDRASES break down carbohydrates into simple sugars.
  • PROTEASES convert proteins into amino acids.
  • LIPASES break down lipids into glycerol and fatty acids.
• • AMYLASE: A type of carbohydrase enzyme that breaks down STARCH into maltose (a simple sugar).
  • PEPSIN: A type of protease enzyme that is produced in the STOMACH. It has a LOW OPTIMUM pH. The hydrochloric acid in the stomach provides a low pH for the pepsin to work at a faster rate. Pepsin breaks down PROTEINS into AMINO ACIDS.
• TRIACETATE: An example of a substrate that can be broken down by triacetate hydrolase. Triacetate hydrolase converts it into three separate molecules of acetic acid.
• • Some products of digestion are used to synthesise new carbohydrates, proteins, and lipids.
  • Other products are utilised in other ways, e.g. glucose is used in respiration to release energy.
• • Digestive enzymes are key in breaking down food into absorbable nutrients.
  • These enzymes are produced by specialised cells in various digestive system GLANDS and the gut lining.
• The Mouth

  • Teeth CHEW the food
  • SALIVARY GLANDS in the mouth secrete AMYLASE enzyme in saliva to begin carbohydrate digestion.
• The Mouth

  • Teeth CHEW the food
  • SALIVARY GLANDS in the mouth secrete AMYLASE enzyme in saliva to begin carbohydrate digestion.
• Oesophagus

  • A tube that connects the mouth to the stomach
• The Stomach

  • Has muscular walls that churn food into smaller pieces
  • It produces PEPSIN, a type of protease enzyme to break down PROTEINS
  • It produces HYDROCHLORIC ACID to KILL BACTERIA and to provide the optimum pH for the pepsin to work in
• The Liver

  • Produces BILE, crucial for NEUTRALISINGstomach acid and EMULSIFYING FATS into smaller droplets
  • The bile is STORED in the GALL BLADDER.
• The Pancreas

  • It produces PROTEASE, CARBOHYDRASE, and LIPASE.
• The Small Intestine

  • It produces PROTEASE, CARBOHYDRASE, and LIPASE.
  • This is where digestion is completed, where the broken down nutrients are ABSORBED into the bloodstream.
• The Large Intestine

  • The large intestine absorbs EXCESS WATERfrom digested food.
  • Waste is eventually moved to the RECTUM as faeces and exits the body through the ANUS.
• mouth

  oesophagus

  stomach

  liver

  pancreas

  small intestine

  large intestine

  anus
• The circulatory system is an ORGAN SYSTEMthat transports many substances including FOODand OXYGEN around the body, so that they can be received by cells.

  It also transports WASTE SUBSTANCES out of cells so that they can be excreted.

   

  It is mainly made out of BLOOD, BLOOD VESSELSand THE HEART.
• 4 components of blood

  1. red blood cells
  2. platelets
  3. plasma
  4. white blood cells