Topic 2- Organisation Flashcards
Define cells.
Cells are the basic building blocks that make up all living organisms.
What does a specialised cell do?
It carries out a particular function.
Define differentiation.
It is the process by which cells become specialised for a particular job.
When does differentiation occur?
It occurs during the development of a multicellular organism.
What does specialised cells form?
It form tissues, which form organs, which form organs systems.
What do large multicellular organisms have?
They have different systems inside them for exchanging and transporting materials.
Define a tissue.
It is a group of similar cells that work together to carry out a particular function. It includes more than one type of cell.
Give 3 examples of tissues in mammals.
- Muscular tissue
- Glandular tissue
- Epithelial tissue
Give the function of a muscular tissue.
It contracts (shortens) to move whatever it’s attached to.
Give the function of a glandular tissue.
It makes and secretes chemicals like enzymes and hormones.
Give the function of an epithelial tissue.
It covers some parts of the body, e.g. the inside of the gut.
Define an organ.
It is a group of different tissues that work together to perform a certain function.
Give 3 tissues which the stomach is made up of.
- Muscular tissue
- Glandular tissue
- Epithelial tissue
Give the function of muscular tissue within the stomach.
It moves the stomach wall to churn up the food.
Give the function of glandular tissue within the stomach.
It makes digestive juices to digest food.
Give the function of epithelial tissue within the stomach.
It covers the outside and inside of the stomach.
Define an organ system.
It is a group of organs working together to perform a particular function.
Give examples of 5 organs which makes up the digestive system.
- Glands (e.g. the pancreas and salivary glands)
- Stomach
- Liver
- Small intestine
- Large intestine
Give the function of glands in the digestive system.
It produces digestive juices.
Give the function of the stomach in the digestive system.
The stomach and small intestine, digest food.
Give the function of the liver in the digestive system.
Produces bile
Give the function of the small intestine in the digestive system.
Absorbs soluble food molecules
Give the function of the large intestine in the digestive system.
Absorbs water from undigested food, leaving faeces.
What are enzymes?
They act as biological catalyst.
Why do we have enzymes?
To speed up the useful chemical reactions in the body.
Define a catalyst.
It is a substance which increases the speed of a reaction, without being changed or used up in the reaction.
What are proteins made up of?
Chains of amino acids
What do chemical reactions usually involve?
It involves things either being split apart or joined together.
What does every enzyme must have to function properly?
An active site with a unique shape that fits onto the substance involved in a reaction.
Why do enzymes only catalyse one specific reaction?
The substrate has to fit into its active sites.
What happens if the substrate doesn’t match the enzyme’s active site?
The reaction won’t be catalysed.
What is the substrate?
It is the substance that an enzyme acts on.
Name the diagram which gives the simplified version of how enzymes work.
‘lock and key’ model of enzyme action
What does the active site do when the substrate binds to it?
The active site changes shape a little as the substrate binds to it to get a tighter fit.
How is the ‘induced fit’ model of enzyme action shown?
When a substrate binds to an enzyme active site.
How can you change the rate of an enzyme- catalysed reaction?
By changing the temperature
What happens to the enzymes when the temperature is too hot? (1)
Some of the bonds holding the enzymes together break.
What happens to the enzymes when the temperature is too hot? (2)
This changes the shape of the enzyme’s active site, so the substrate won’t fit any more. The enzyme is said to be denatured.
What is essential for all enzymes to have in order to work efficiently?
An optimum temperature that they work best at.
Give another factor which affects enzymes.
pH
What happens to the enzymes if the pH is too high or too low?
The pH interferes with the bonds holding the enzyme together.
What consequence does it have on the enzyme if the pH is too high or too low?
This changes the shape of the active site and denatures the enzyme.
What do all enzymes must have in order to work efficiently? (2)
An optimum pH that they work best at.
What is the optimum pH for most enzymes?
pH 7
What is pepsin?
It is an enzyme used to break down proteins in the stomach (protease).
What does the pH of pepsin mean?
It means it’s well-suited to the acidic conditions there.
What is the right pH for pepsin?
pH 2
What breaks down big molecules?
Digestive enzymes
Give 3 examples of big molecules broken down by digestive enzymes.
- Starch
- Lipids
- Proteins
What is the problem with big molecules?
Too big to pass through the walls of the digestive system.
Give 4 examples of smaller molecules.
- Sugars (e.g. glucose and maltose)
- Amino acids
- Glycerol
- Fatty acids
Why are smaller, soluble molecules able to be absorbed into the bloodstream?
They can pass easily though the walls of the digestive system.
Give 3 locations of where amylase enzymes are used.
- Salivary glands
- Pancreas
- Small intestine
Give the function of amylase.
Breaks down starch
What is amylase an example of?
Carbohydrase
What is starch?
A carbohydrate
What is starch broken down into by amylase?
Maltose and other sugars, e.g. dextrins
Give 3 locations for protease enzymes.
- Stomach (it’s called pepsin there)
- Pancreas
- Small intestine
Give the function of protease.
Breaks down proteins
What are proteins broken down into by protease?
Amino acids
Give 2 locations for lipase enzymes.
- Pancreas
2. Small intestine
Give the function of lipase.
Breaks down lipids
What are lipids broken down into by lipase enzymes?
Glycerol and fatty acids
What is some of the glucose (a carbohydrate) that’s made used for?
Respiration
What can the products of the broken down molecules be used for?
To make new carbohydrates, proteins and lipids.
Where is bile produced?
Liver
Where is bile stored?
In the gall bladder
Where is the bile released after being stored in the gall bladder?
Into the small intestine
What is the problem with hydrochloric acid for enzymes in the small intestine?
It makes the pH too acidic for enzymes in the small intestines to work properly.
What is bile?
It is alkaline- it neutralises the acid and makes conditions alkaline.
What conditions do enzymes work best at in the small intestine?
Alkaline conditions
What does bile do?
It emulsifies fat.
What does it mean to emulsify fat?
Break the fats into tiny droplets.
Why is it really useful to emulsify fat?
It gives a much bigger SA of fat for the enzymes lipase to work one- which makes digestion faster.
What are enzymes in the digestive system produced by?
Specialised cells in glands and in the gut lining.
Give the function of salivary glands.
These produce amylase enzyme in the saliva.
What does the liver produce?
Bile
What does bile do? (2)
Neutralises stomach acid and emulsifies fats.
Give the function of gall bladder.
To store bile before it’s released into the small intestine.
Give the function of large intestine.
It is where excess water is absorbed from the food.
What are faeces made up of?
Made up mainly of indigestible food.
Give the function of rectum.
It is where the faeces are stored before they go through the anus.
What does the stomach produce?
- Protease enzyme (pepsin)
2. Hydrochloric acid
Give the function of the stomach.
Pummels the food with its muscular walls.
Give 2 reasons why hydrochloric acid is produced in the stomach.
- To kill bacteria
2. To give the right pH for the protease enzyme to work (pH 2- acidic)
What enzymes does the pancreas release?
- Protease enzymes
- Amylase enzymes
- Lipase enzymes
What does the pancreas do with the enzymes?
Releases them into the small intestine.
What enzymes does the small intestine produce?
- Protease enzymes
- Amylase enzymes
- Lipase enzymes
Why does the small intestine release enzymes?
To complete digestion.
What is the role of the small intestine?
It is where the digested food is absorbed out of the digestive system into the blood.
Give another name for gullet.
Oesophagus
Where is the thorax?
Top part of your body.
What is the thorax separated by?
From the lower part of the body by the diaphragm.
Describe what the lungs look like.
They are like big pink sponges.
What are the lungs protected by?
Ribcage
What are the lungs surrounded by?
Pleural membranes
Where does the air you breathe in go through?
The trachea
What does the trachea split into?
This splits into two tubes called bronchi (each one is a bronchus), one going to each lung.
What does the bronchi split into?
It split into progressively smaller tubes called bronchioles.
Where does the bronchioles end up at?
Small bags called alveoli.
Where does gas exchange take place in the lungs?
In alveoli
What does the lung contain?
Millions and millions of little air sacs called alveoli.
What are alveoli surrounded by?
A network of blood capillaries.
What is the circulatory system made up of?
- Heart
- Blood vessels
- Blood
What do humans have? (circulatory system)
A double circulatory system- two circuits joined together.
What is deoxygenated blood?
Blood without oxygen
Give the function of the right ventricle.
Pumps deoxygenated blood to the lungs to take in oxygen. The blood then returns to the heart.
Give the function of a left ventricle.
It pumps oxygenated blood around all the other organs of the body.
What does the blood do when it gets at the body cells?
It gives up its oxygen and the deoxygenated blood returns to the heart to be pumped out to the lungs again.
What is the heart?
A pumping organs that keeps the blood flowing around the body.
What are the walls of the heart mostly made of?
Muscle tissue
What does the heart have?
Valves
Give the function of a valve?
To make sure that blood flows in the right direction- they prevent it flowing backwards.
Give 4 chambers the heart has.
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
What does the heart also need to function?
Its own supply of oxygenated blood.
How does the heart get all the oxygenated blood it needs?
By arteries called coronary arteries.
How is the resting heart rate controlled?
By a group of cells in the right atrium that act as a pacemaker.
What do pacemaker cells produce?
A small electrical impulse which spreads to the surrounding muscle cells, causing them to contract.
Why do some people use artificial pacemakers?
To control heartbeat if the natural pacemaker cells don’t work properly.
In which circumstances do people need artificial pacemakers?
If the patient has an irregular heartbeat.