Glossary:
Living organisms are made of cells. Some organisms are only one cell big.
Tissues are made of a group of specialised cells. They work together to carry out a role. �
These are larger structures within an organism, made up of different tissues, that carry out a particular role, or roles.
A living thing is called an organism. They can be as simple as a single cell, or complex, and made up of complex organ systems.
These are biological catalysts that speed up reactions. They are made of protein, and have a specific shape.
This the molecule/s that are broken down, or built up, by an enzyme. Each substrate binds to a specific enzyme due to its shape.
These are special structures that secrete enzymes in digestion.
This is the system that is involved in getting Oxygen into the body via the lungs.
This is the system that distributes blood around the body. The blood is pumped by the heart, and sent around the body in blood vessels.
This is the term used to describe the diseases caused by Malignant tumours (made by uncontrolled cell growth). �
Levels of Organisation within a living organism
Organelles → Cells → Tissues → Organs → Organ systems
*Single celled organisms do not have tissues/organs.
Enzymes
These proteins carry out very special roles in chemical reactions. They allow for molecules to be made, or broken down. As seen below every enzyme works with a specific substrate/s. The substrate/s binds to the ACTIVE SITE, forming an Enzyme-substrate complex. We call this specific matching the “lock and Key” hypothesis.
Enzyme performance�Enzyme’s are fussy, and work�best under certain conditions.�Factors that can effect the�structure of an enzyme (pH or�Temperature) can cause the�active site to change. If this happens the substrate cannot bind properly (if at all), and therefore the reaction can’t happen. When this happens we say the enzyme has become denatured.
Students need to know how to measure the rate of an enzyme driven reaction. It’s calculated by monitoring the change in a specific substrate, divided by the time taken for the change.
B2: Organisation
Food tests
Gas exchange
In the lungs you’ll find tiny air sacs called�Alveoli. This air sacs inflate with air�when you inhale. Oxygen from inside the �alveoli will then diffuse into the blood�(down a concentration gradient), and�Carbon Dioxide will diffuse out of the�blood and into the air.
The Heart
Your heart is a muscular bag that�carries out one job, and that is�to pump blood around the body.�It is a double pump, in that it sends�blood to the lungs to collect Oxygen,�before it comes back to the heart�ready to be sent all across the body. �It contains Valves to prevent backflow..�
Blood Vessels
Arteries carry blood�from the heart under�great pressure.�Veins carry blood back�to the heart under less�pressure. They have�valves to prevent backflow.�Capillaries are the site of�substance exchange. They �have very thin walls to�help with diffusion.
Digestive system
Students need to know the role�of each organ in the digestive�system.
This includes how they are�involved in either the mechanical,�or chemical (via enzymes)�breakdown of foods.
Key info includes pH of stomach (2),�and the pH of the small intestine (6-7). The pH �effects the performance of the enzymes in the organ.
B2: Organisation
Blood
Blood is a mixture that contains:�
Plasma – This is the liquid part of the blood that all cells are suspended in. It also carries dissolved nutrients, and CO2.
Red Blood Cells – These cells carry Oxygen around the body. They contain Haemoglobin to help them do this.
White blood cells – These make up your immune system, and protect us from disease.
Platelets – These are essential in helping your blood to clot when you have a cut.�
Faulty heart…
If CHD has led to a faulty heart then options are available to treat the conditions.
Sometimes the heart naturally wears, and valves degrade. These can be replaced with Biological (from other humans, or animals), or Mechanical Valves. This is less drastic than a whole heart transplant, however it is still major surgery.
Non-Communicable Diseases
Diseases that are not caused by pathogens (bacteria/Virus/Fungi), and cannot be transferred from one person to another are called Non-communicable. These include Asthma, Cancer, and CHD. None of these diseases can be caught from another person.
Many non-communicable diseases can be linked to your lifestyle. Where certain actions can increase your chance of developing the diseases. These include smoking, drinking alcohol, a poor diet.
Non-communicable, lifestyle diseases, are the fastest growing diseases in the developed world.
CHD – Coronary Heart Disease
This is a disease where the arteries that supply the heart itself with blood start to build up layers of fat. The layers of fat narrow the lumen that blood can flow through, restricting the amount of blood reaching the heart muscle. This can stop the heart muscle getting the Oxygen and nutrients it needs.
This can be prevented by eating less fatty�foods. However, if CHD occurs it can be�treated by:-
Statins – These lower (bad –LDL) Cholesterol,�which stops the build up of fats.
Stents – This requires surgery. A wire mesh is �put into the blood artery, widening the lumen.
B2: Organisation