inte sci chemical dig

• Chemical digestion


  Involves enzymes, which are organic catalysts that speed up chemical reactions occurring in living cells
• Substrate


  The substance that the enzyme breaks down
• Products


  The substances that are made
• Digestive enzymes


  • Carbohydrase (amylase) - digests polysaccharides into disaccharides and monosaccharides
  • Protease - digests proteins into amino acids
  • Lipase - digests lipids into fatty acids + glycerol
• Enzymes


  • They are all proteins
  • Each enzyme is specific for the type of chemical reaction it speeds up
  • They are required in small amounts
• Digestion in the mouth

  1. Teeth break food down into smaller pieces

  2. Saliva moistens the food

  3. Salivary amylase begins to digest the starch in the food
• Digestion in the stomach

  1. Muscular walls relax and contract to churn the food

  2. Food is mixed with enzymes, mucus and hydrochloric acid

  3. Pepsin digests proteins into amino acids

  4. Hydrochloric acid provides acidic medium for pepsin

  5. Rennin curdles milk in young mammals
• A peptic ulcer is a hole or 'sore' in the stomach lining, caused by Helicobacter pylori bacteria
• Digestion in the intestines

  1. Duodenum receives chyme from stomach and secretions from gall bladder and pancreas

  2. Bile emulsifies fats

  3. Pancreatic juice contains enzymes like amylase, lipase and trypsin

  4. Pancreatic juice neutralizes stomach acid
• Ileum


  • About 6 metres long with large surface area
  • Has folds, ridges and villi to increase surface area for absorption
• Colon


  Reabsorbs water from faeces into bloodstream
• Absorption


  Process where soluble food molecules move into body fluids and cells through intestinal walls
• Assimilation


  Process of making use of the digested food into the body
• Fate of digested food molecules

  • Monosaccharides (glucose) - taken to liver, used in respiration, excess converted to glycogen or fat
  • Amino acids - taken to liver, used for growth, repair, hormones, enzymes, excess converted to glycogen, fat or urea
  • Fatty acids - carried by lymph to blood, stored as fat, used to form new cell membranes, used for respiration
• Egestion


  Process of removing undigested food from the body as faeces
• What is the main function of enzymes in chemical digestion?

  To break down large molecules into smaller ones that can be absorbed and utilized by the body.
• Which enzyme is responsible for breaking down proteins into smaller peptides?

  Pepsin
• Where is amylase produced in the body?

  Mouth and pancreas
• Which stage of digestion is responsible for breaking down proteins into smaller peptides?

  Stomach
• What is the main function of amylase in the process of digestion?

  To break down carbohydrates into simpler sugars
• In which part of the digestive system do most of the nutrient absorptions take place?

  Small intestine
• Which enzyme breaks down fats into fatty acids and glycerol in the small intestine?

  Lipase
• Which part of the digestive system secretes enzymes into the small intestine?

  Pancreas
• What is the primary function of enzymes in the small intestine?

  To break down carbohydrates, proteins, and fats into smaller molecules that can be absorbed.
• Hardware

  The tangible components of a computer system (the parts of the computer that can be seen and touched)
• Examples of hardware


  • mouse
  • keyboard
  • monitor
  • scanners
• Categories of computer devices

  • Input
  • Output
  • Storage
• Peripheral devices


  Any hardware device connected to and controlled by the central processing unit (CPU)
• Input, output and storage devices are also referred to as peripheral devices
• Input devices


  Any peripheral device that is connected to the computer system that allows the user to send data into the computer system
• Examples of input devices

  • Keyboard
  • Mouse
  • Light Pen
  • Microphone
  • Scanners
  • Barcode Readers
  • Optical Character Reader
  • Optical Mark Reader
• Output devices


  Any peripheral device that is connected to the computer system that allows the user to produce meaningful information (printed or soft copy)
• Examples of output devices

  • Printers (impact and non-impact; types; line, page, laser, inkjet, dot matrix)
  • Plotters
  • Speakers
  • Monitors
  • Multimedia projectors
  • Headphones
• Storage devices


  Devices used to back up information for later use
• Types of computer storage

  • Temporary (primary memory)
  • Permanent (secondary memory)
• Primary memory


  Highly electrical storage with no moving parts, very fast and reliable but needs to be supplemented by secondary storage
• Types of primary memory

  • RAM (Random Access Memory)
  • ROM (Read Only Memory)
• RAM


  The place in a computer where the operating system, application programs, and data in current use are kept so that they can be quickly reached by the computer's processor, but it cannot hold data permanently
• ROM


  Built-in computer memory containing data that normally can only be read, not written to, contains the programming that allows your computer to be "booted up" or regenerated each time you turn it on, the data in ROM is not lost when the computer power is turned off
• Types of Read Only Memory

  • BIOS (Basic Input Output System)
  • PROM (Programmable Read Only Memory)
  • EPROM (Erasable Read Only Memory)
  • EEPROM (Electrically Erasable Programmable Read Only Memory)