topic 2 - organisation Flashcards
What is a cell?
- Basic building blocks of all living organisms
What is a tissue?
a group of cells with similar structures working together for a specific function
What is an organ?
a group of tissues working together for a specific function e.g. the stomach
What are three examples of tissues?
Muscle tissue - contracts (shortens) to move what it’s attached to. They contain special protein fibres which change their length. They are also packed full of mitochondria, providing the energy needed for contraction. Muscle cells work together to form muscle tissue
Glandular tissue - makes and secretes substances like enzymes and hormones
Epithelial tissue - covers the outside and inside of the stomach
What is an organ system?
A group of organs working together to perform specific functions. e.g. digestive system
What are the three main nutrients food contain?
- Carbohydrates (e.g starch)
- Protein
- Lipids (fats)
What is the main function of the digestive system?
To digest food and absorb the nutrients obtained from digestion
What is the role of the pancreas in the digestive system?
The pancreas releases enzymes which continue the digestion of starch and protein. They also start the digestion of lipids.
What is the role of the stomach in the digestive system?
Produces hydrochloric acid which kills any bacteria present and provides the optimum acidic pH for the protease enzyme to function
What is the role of the small intestine in the digestive system?
- The small intestine is where soluble food molecules are absorbed into the bloodstream by diffusion or active transport.
What is the role of the liver in the digestive system?
- This releases bile which emulsifies lipids and allows the lipase enzyme to work more efficiently.
- Bile also neutralises the acid released from the stomach
What is the role of the large intestine in the digestive system?
Absorbs water from undigested food producing faeces
What is the role of enzymes?
Biological catalysts that speed up the rate of biological reactions without being used up
What is an active site?
The site on an enzyme where the substrate binds
How does the shape of an enzyme affect its function?
Enzymes have a specific active site which is complementary to their substrate
What is metabolism?
The sum of all the reactions in a cell or an organism
What is the lock and key hypothesis of enzyme function?
- Enzymes are specific and will only catalyse particular substrates
- The substrate must fit the active site of the enzyme or it will not catalyse
- After the reaction occurs the enzyme now breaks down the substrate into the products and binds to another substrate
How does temperature affect enzyme action?
- As the temperature increases the enzyme activity also increases. This is because the enzyme and the substrate are moving faster so there are more collisions per second between the substrate and the active site.
- At a certain temperature, the enzyme is working at the fastest possible rate. This is the optimum temperature. At this point, there is the maximum frequency of successful collisions between the substrate and the active site.
- If they go beyond this temperature, the activity of the enzyme rapidly decreases to zero.
- At high temperatures, the enzyme molecule vibrates and the shape of the active site changes.
- Now the substrate no longer fits perfectly into the active site. The active site is denatured
How does pH affect enzyme function?
- The enzyme has an optimum pH where the activity is maximum
- If we make the pH more acidic or more alkaline then the activity drops to zero
- The active site denatures if the conditions are too acidic or too alkaline
What is the role of amylase in the digestive system?
amylase breaks down starch into simple sugars (glucose)
Which organs produce amylase?
salivary glands and pancreas
Where does starch digestion occur?
Mouth + small intestine
What is the role of proteases in the digestive system?
Proteases break down protein into amino acids
Which organs produce proteases?
Pancreas and small intestine