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Flashcards in Organisation Deck (43):

What is a tissue?

A group of similar cells that work together to carry out a particular function.


What is the role of muscular tissue?

It contracts to move whatever it’s attached to.


What is the role of glandular tissue?

It makes and secretes chemicals like enzymes and hormones.


What is the role of epithelial tissue?

It covers some parts of the body for example the inside of the gut.


What is an organ?

It is a group of different tissues that work together to perform a certain function.


Which tissues is the stomach made of?

Muscular tissue, glandular tissue, epithelial tissue.


What is an organ system?

It is a group of organs working together to perform a particular function.


What is the function of the digestive system?

It breaks down and absorbs food.


What is the function of the glands e.g. the pancreas and saliva glands?

They produce digestive juices (amylase enzyme in the saliva)


What is the function of the stomach and small intestine?

They digest food.


What is the function of the liver?

It produces bile which neutralises stomach acid and emulsifies fats


What does the small intestine absorb?

It absorbs soluble food molecules. The digested food is absorbed out of digestive system into blood


What does the large intestine absorb?

It’s absorbs excess water from undigested food, leaving faeces.


What is a catalyst?

It is a substance which increases the speed of a reaction, without being changed or used up in the reaction.


What is an examples of a biological catalyst?

Enzymes are biological catalysts As they speed up the useful chemical reactions in the body


How does an enzyme work?

The substrate has to fit into its active site so that the reaction is catalysed. This is also known as the lock and key model of enzyme action


What happens if you change the temperature of the reaction?

It changes the rate of an enzyme catalysed reaction. A higher temperature will increase the rate and the lower temperature will decrease the rate of the reaction.


What happens if the temperature becomes too hot?

Some of the bonds holding the enzyme together will break which changes the shape of the enzymes active site so the substrate won’t fit no more and so the enzyme becomes denatured


What is an enzymes optimum temperature?

The temperature that the enzymes catalyse best at


What happens if you change the PH in the reaction?

If it’s too high or low, the PH interferes with the bonds holding the enzyme together and this changes the shape of the active site and denatures the enzyme


What is the usual optimum pH that enzymes work best at?

It is often neutral pH seven but not always. For example, pepsin breaks down proteins in the stomach and works best at PH2 which means it prefers acidic conditions


How would you calculate the rate of reaction?

Rate s-1 = 1000 / time


What are examples of big molecules?

Starch, proteins, fats. They are too big to pass through the walls of the digestive system so digestive enzymes break down these big molecules


What are big molecules broke down into?

They are broke down into smaller molecules such as sugars.For example, amino acid’s, glycerol and fatty acid’s


Why do molecules need to be small?

They are more easily passed through the walls of the digestive system and are absorbed into the bloodstream easier


What is amylase?

It is an example of carbohydrase. Enzyme that breaks down starch.


Where is amylase created?

The salivary glands, the pancreas, the small intestine.


What is protease?

They convert proteins into amino acid’s


Where are proteases created?

In the stomach, pancreas, Small intestine.


What is lipase?

It converts lipids into glycerol and fatty acid’s


Where are lipases created?

In the pancreas, the Small intestine


What is bile?

It is produced in the liver. It’s stored in the gallbladder before it is released into the small intestine


Why is bile alkaline?

Because it neutralises the acid in the stomach and makes conditions alkaline so that the enzymes can work properly in these conditions


What is the function of the stomach?

It’s pummels food with its muscular walls and it produces the protease enzyme, pepsin.


Why does the stomach produce hydrochloric acid?

To kill bacteria and to give the right PH for the protease enzyme to work


What is the gullet?

The oesophagus. Where food travels before entering the stomach.


What is the function of the rectum?

Whether faeces are stored before they are excreted through the anus


What are faeces made up of?

Mainly indigestible food


How do you prepare the food sample before the food test?

You would break up the food using a pestle and mortar. Can you replace the ground up food into a beaker and add some distilled water. Give the mixture a good stir with a glass rod to dissolve some of the food and filter the solution using a funnel to get rid of the solid bits of food


What is the function of the lungs?

To transport oxygen to blood and remove CO2 from it


How is the alveoli adapted for gas exchange?

-huge SA (75m2)
-moist lining for dissolving gases
-very thin walls
-good blood supply


How can the effectiveness of an exchange surface be maximised?

-thin membrane
-large SA
-animals-lots of blood vessels/ ventilated for air to get in and out


What is the function of the villi?

-covers the small intestine
-increase the SA al digested food is absorbed much more quickly
-a very good blood supply