Organisation Flashcards
What are cells?
Cells are the basic unit of life - they make up all living things
What are tissues?
A tissue is a group of specialised cells with a similar structure and function. They can be made of more than one type of cell. Examples include muscular tissue or epithelial tissue.
What are organs?
Organs are formed from a number of different tissues, working together to produce a specific function. An examples is the stomach, which has muscular tissue and epithelial tissue.
What are organ systems?
Organs are organised into organ systems, which work together to perform a certain function. The stomach is part of the digestive system, along with organs such as the liver and small intestine.
Which glands produce digestive juices to break down food?
Salivary glands and the pancreas
What function does stomach acid serve?
The stomach produces hydrochloric acid to kill bacteria and to provide the optimum pH for the protease enzyme to work.
Where are small soluble molecules absorbed in the digestive system?
The small intestine.
What organ produces bile and where is it stored?
The liver produces bile and it is stored in the gall bladder
What does the large intestine do?
Absorbs water from undigested food to produce faeces. This passes out of your body through the rectum and anus.
What are enzymes?
Proteins that are biological catalysts (a substance that increases the rate of reaction without being used up)
How do enzymes work?
Each enzyme has its own uniquely shaped active site where the substrate binds. They can both break up large molecules and join small ones.
What factors affect enzyme function?
pH and temperature.
How does temperature affect enzymes?
○ The rate of reaction increases with an increase in temperature up to this optimum, but above this temperature it rapidly decreases and eventually the reaction stops.
○ When the temperature becomes too hot, the bonds in the structure will break
○ This changes the shape of the active site, so the substrate can no longer fit in
○ The enzyme is said to be denatured and can no longer work
What do carbohydrases do?
convert carbohydrates into simple sugars. Example: Amylase - breaks starch down to maltose
What do proteases do?
convert proteins into amino acids. Example: pepsin which is produced in the stomach
What do lipases do?
convert lipids into fatty acids and glycerol.
What is the test for sugars?
Benedict’s test for sugars (turns brick red)
What is the test for starch?
Iodine test for starch (turns blue-black)
What is the test for protein?
Biuret test for protein (turns purple)
What is the function of bile?
Neutralises stomach acid and emulsifies fat in to small droplets, so there is a larger surface area for lipases to act on.
Is the human circulatory system double or single?
Double
1: Deoxygenated blood flows into the right atrium and then into the right ventricle
which pumps it to the lungs to undergo gaseous exchange
2: Oxygenated blood flows into the left atrium and then into the left ventricle
which pumps oxygenated blood around the body”
How many chambers are in the heart?
Four - two atria and two ventricles
What are the function of valves?
make sure blood does not flow backwards