Topic 2- Organisation

    Cards (96)

    • cells
      basic functional and structural units in a living organism
    • Tissue
      A group of cells of similar structure working together to form a particular function
    • Organs
      made from a group of different tissues working together to form a particular function
    • organ system
      made from a group of organs with related functions, working together to perform functions in the organism
    • Role of the stomach
      To start protein digestion
    • Protein digestion in the stomach
      1. Stomach produces proteases like pepsin
      2. Proteases digest proteins into amino acids
    • Hydrochloric acid
      • Aids protein digestion
      • Helps proteins unravel so enzymes can break bonds holding amino acids together
      • Inhibits many microorganisms that may be present in food, reducing chance of infection
      • Acid produced by glandular tissue in the stomach
    • Digestive system
      A number of organs that break down large insoluble molecules into smaller, soluble food molecules to provide the body with nutrients
    • Three types of tissue found in the stomach are muscular, epithelial and glandular. These tissues work together to allow the stomach to carry out its role
    • Digestive system
      An example of an organ system in which several organs work together to digest and absorb food
    • Digestion
      1. Large, insoluble molecules in food (such as starch, proteins) are broken down into smaller, soluble molecules
      2. Smaller, soluble molecules (such as glucose and amino acids) are absorbed into the bloodstream and delivered to cells in the body
    • Small soluble molecules

      Used either to provide cells with energy (via respiration), or with materials with which they can build other molecules to grow, repair and function
    • Alimentary canal

      • teeth are responsible for mechanical digestion
      • The oesophagus pushes the bolus towards the stomach by peristalsis
      • the stomach will break down food by churning and digest protein using protease
      • Hydrochloric acid will kill bacteria and create an acidic pH
    • Alimentary canal (2)

      • Digestion is completed in the duodenum
      • soluble food molecules are absorbed in the ileum due to the presence of villi
      • Water is absorbed in the colon and faeces is formed
      • Stored in rectum before leaving through anus
    • Accessory organs+functions
      • salivary glands- secrete amylase for starch digestion
      • pancreas- produces various digestive enzymes in an alkaline fluid
      • gall bladder- where bile is stored
      • Liver- where Bile is produced for the emulsification of lipids+ increase in pH
    • Mouth

      Where mechanical digestion takes place
    • Mechanical digestion in the mouth
      1. Teeth chew food to break it into smaller pieces
      2. Increase surface area to volume ratio
      3. Amylase enzymes in saliva start digesting starch into maltose
    • Bolus formation
      1. Tongue shapes food into a ball
      2. Saliva lubricates the bolus so it can be swallowed easily
    • Oesophagus
      • Tube that connects the mouth to the stomach
      • Wave-like contractions push the food bolus down without relying on gravity
    • Stomach
      • Food is mechanically digested by churning actions
      • Protease enzymes start to chemically digest proteins
      • Hydrochloric acid kills bacteria and provides optimum pH for protease enzymes
    • Small intestine

      • Duodenum is where food from the stomach finishes being digested by enzymes produced here and from the pancreas
      • pH is slightly alkaline (around 8-9)
      • Ileum is where absorption of digested food molecules takes place, it is long and lined with villi to increase surface area
    • Large intestine

      • Water is absorbed from remaining material in the colon to produce faeces
      • Faeces is stored in the rectum and removed through the anus
    • Pancreas
      • Produces amylase, protease and lipase enzymes
      • Secretes enzymes in an alkaline fluid into the duodenum to raise the pH of fluid coming out of the stomach
    • Liver
      • Produces bile to emulsify fats (mechanical digestion)
      • Breaks down amino acids not used to make proteins (deamination) which produces urea
    • Gall bladder
      Stores bile to release into the duodenum as required
    • Digestive system
      organs
      A) salivary glands
      B) stomach
      C) bile duct
      D) large intestine
      E) rectum
      F) anus
      G) appendix
      H) small intestine
      I) pancreas
      J) gall bladder
      K) liver
      L) oesophagus
      M) mouth
    • Large intestine
      Home to hundreds of species of bacteria
    • Microbial ecosystem (microbiota, gut flora)

      Bacteria that play an essential role in human digestion of food
    • Role of gut microbiota in human digestion

      1. Breaking down substances we can't digest (like cellulose)
      2. Supplying essential nutrients
      3. Synthesising vitamin K
      4. Providing competition with any harmful bacteria to restrict their growth
    • Taking antibiotics

      Can disrupt the gut microbiota
    • Disrupting the gut microbiota
      Can cause short-term problems with digestion
    • enzyme- biological catalyst
    • Enzymes
      Lock& Key model (bottom labels are unscientific)
      A) Enzyme
      B) Lock
      C) Active site
      D) Substrate
      E) Key
    • Enzyme specificity
      can only catalyse reactions with the correct shaped substrate
    • Metabolism
      The sum of all the reactions happening in a cell or organism, in which molecules are synthesised (made) or broken down
    • Enzymes& metabolism

      • They speed up chemical reactions in cells, allowing reactions to occur at much faster speeds than they would without enzymes at relatively low temperatures (such as human body temperature)
      • They temporarily bind to the active site of an enzyme, which leads to a chemical reaction and the formation of a product(s) which are released
      • They remain unchanged at the end of a reaction, and they work very quickly
    • How temperature affects enzymes

      • As temperature increases so does kinetic energy, which means more substrate complexes are formed
      • the temperature with the highest rate of reaction is the optimum temperature
      • When the temperature is high enough to break the bonds in the amino acids- enzyme denatures and loses its shape
    • Optimum pH for most enzymes
      • pH 7
      • Some enzymes produced in acidic conditions have lower optimum pH (pH 2)
      • Some enzymes produced in alkaline conditions have higher optimum pH (pH 8 or 9)
    • If pH is too high or too low
      Bonds that hold the amino acid chain together to make up the protein can be destroyed
    • Bonds that hold the amino acid chain together being destroyed
      Changes the shape of the active site