Organisation 1 Flashcards
Cell organisation, The digestive system.
What are cells?
The basic building blocks of all living organisms.
What is a tissue?
A group of cells with similar structure and function.
What is an organ?
A group of tissues performing specific functions.
What do organ systems work together to form?
Organisms.
What do specialised cells do?
Carry out a particular function.
What do specialised cells form?
Tissues, which form organs, which form organ systems.
Give examples of tissues in mammals.
-Muscular tissue
-Glandular tissue
-Epithelial tissue
What does muscular tissue do?
Contract to move whatever it’s attached to.
What does glandular tissue do?
Makes and secretes chemicals like enzymes and hormones.
What does epithelial tissue do?
Cover some parts of the body, e.g. the inside of the gut.
What is an organ system?
A group of organs working together to perform a particular function.
How is the stomach (organ) adapted for its role in digestion?
It is made up of three types of tissue:
-Muscular tissue
-Glandular tissue
-Epithelial tissue
What is the function of muscular tissue in the stomach?
It contracts, causing the wall of the stomach to move and churn up food.
What is the function of glandular tissue in the stomach?
Secretes acid and enzymes (in digestive juices) which help to break down food chemically in the stomach cavity.
What is the function of epithelial tissue in the stomach?
To cover and protect the outside and the inside of the stomach.
How much longer is the stomach than an epithelial cell?
Over 1000x longer.
Epithelial cells are less than 0.1mm in length.
What is the digestive system?
An example of an organ system in which several organs work together to digest and absorb food.
Give an example of an organ system.
The digestive system.
The respiratory system.
The circulatory system.
The urinary system .
What organs is the digestive system made up of?
-Salivary glands
-Oesophagus (gullet)
-The liver
-The gall bladder
-The stomach
-The pancreas
-The small intestine
-The large intestine
-The rectum
What is the role of glands in the digestive system?
To produce digestive juices containing digestive enzymes
Which glands are involved in the digestive system?
-Salivary glands
-Pancreas
What is the role of the stomach?
To digest food
What is the role of the large intestine?
To absorb water from undigested food, leaving faeces.
Knowledge of enzymes relates to…
Metabolism
Why do chemical reactions need to be carefully controlled?
(inside organisms)
So that organisms get the right amount of substances.
Why is raising the temperature inside of a living creature not an effective way of increasing the rate of the chemical reactions occurring in it?
-Raising the temperature would increase the rate of unwanted reactions, not just the useful ones.
-If temperature becomes too high inside a living creature, it’s cells start to become damaged.
What are enzymes?
Large proteins that act as biological catalysts.
What is a catalyst?
A substance which increases the speed of a reaction without being changed or used up in the reaction.
What do enzymes reduce the need for?
High temperatures?
What do enzymes speed up?
ONLY USEFUL chemical reactions in the body.
What are enzymes made up of?
They are large proteins, so are made up of chains of amino acids.
These chains are folded into unique shapes, allowing enzymes to catalyse specific reactions.
Enzymes catalyse specific reactions in living organisms due to what?
The shape of their active site.
If the substrate doesn’t match the enzyme’s active site, then…
the reaction won’t be catalysed.
What is the name for the substance that an enzyme acts on?
The substrate
Lock and key theory
A simplified model used to explain enzyme action.
Explain why enzymes have an optimum pH.
If the pH is too high or low, it can interfere with the bonds holding the enzyme together.
This changes the shape of the active site and denatures the enzyme.
What happens if enzymes become denatured?
The substrate will not bond to the active site (as the active site is no longer complementary) and so the reaction will not be catalysed.
Explain why enzymes have an optimum temperature.
If the temperature is too high, some of the bonds holding the enzyme together break.
This changes the shape of the active site and denatures the enzyme.
When the enzyme is most active, it it at its…
-Optimum temperature
or
-Optimum pH