Flashcards in Cell Organisation Deck (30):
What is a tissue?
A tissue is a group of similar cells that work together to carry out a particular function. (it can contain more than one type of cell.)
Explain what is meant by the term organ system.
An organ system is group of organs working together to perform a particular function.
Why can enzymes be described as biological catalysts?
As enzymes reduce the need for high temperatures and we only have enzymes to speed up the useful chemical reactions in the body.
Why do enzymes only usually catalyse one reaction?
For an enzyme to work, the substrate has to fit into its active site. If the substrate doesn't match the enzyme's active site, then the reaction won't be catalysed.
What does it mean when an enzyme has been denatured?
I f the reaction gets too hot, some of the bonds holding the enzyme together real. This changes the shape of the enzymes active site, so the substrate won't fit any more. This enzyme is said to be denatured.
Describe how you could investigate the effect of pH on the rate of amylase activity.
The enzyme amylase catalyses the breakdown of starch to maltose. It is easy to detect starch using iodine solution - if starch is present, the iodine solution will change from browny-orange to blue-black. This is how you can investigate how pH affects amylase activity.
List the three places where amylase is made in the human body.
-The small intestine
What is the role of lipase?
Lipases convert Lipids into Glycerol and Fatty acids.
Where is bile stored?
Stored in the gall bladder before its released to the small intestine.
Name the solution that you would use to test for the presence of lipids in a food sample.
Name the tubes that split off the trachea.
Explain the role that alveoli play in gas exchange.
Removes Carbon dioxide from the blood through diffusion to be breathed out.
Explain why the circulatory system in humans is described as a 'double circulatory sytem'
Because it is two circuits joined together.
-the right ventricle pumps deoxygenated blood to the lungs to take in oxygen. The blood the returns to the heart.
-the left ventricle pumps oxygenated blood around all the other organs of the body. The blood gives up its oxygen at the body cells and the oxygenated blood returns to the heart to be pumped out to the lungs again.
Why does the heart have valves?
The heart has valves to male sure that blood flows in the right direction - they prevent it flowing backwards.
Name the four chambers of the heart.
How is the resting heart rate controlled in a healthy heart?
Your resting heart rate it controlled by a group of cells in the right atrium wall that act as a pacemaker.
These cells produce a small electrical impulse which spreads to the surrounding muscle cells, causing them to contract.
How are arteries adapted to carry blood away from the heart?
The walls are thick compared to the size of the hole down the middle (lumen)
They contain thick layers of muscle to make them strong, and elastic fibres to allow them to stretch and spring back.
Why do red blood cells not have a nucleus?
Because it allows for more room to carry oxygen.
Give two advantages and disadvantages of statins.
Statins can reduce risk of strokes, coronary heart disease and heart attacks.
Reduce the amount of 'bad' cholesterol, statins increases the amount of beneficial cholesterol in blood stream.
Statins are a long term drug must be taken regularly - risk someone could forget to take them.
negative side-effects (kidney failure, liver damage and memory loss)
What is the difference between biological and mechanical replacement heart valves?
taken from other humans or mammals.
What is meant by a non-communicable disease?
Non communicable diseases are those that cannot spread between people or between animals and people. They generally last for a long time and get worse slowly. e.g: Asthma, cancer and coronary heart disease.
What is meant by a risk factor of a disease?
Risk factors are things that are linked to an increase in the likelihood that a person will develop a certain disease during their lifetime. They done guarantee that someone will get the disease.
Which type of tumour is cancerous?
Malignant - Tumour grows and spreads to neighbouring healthy tissue. Cells can breakout and spread to other parts of the body by travelling in the bloodstream. The Malignant sells the invade healthy tissues elsewhere in the body and form secondary tumours. Malignant tumours are dangerous and can be fatal - they are cancers.
List the tissues that make up a leaf.
-Palisade mesophyll tissue.
-Spongy mesophyll tissue.
Explain how the structure of the upper epidermal tissue in a leaf is related to its function.
It covers the entire plants, and is transparent which allows light to pass through it to the palisade.
What is the function of phloem?
Transport food substances (mainly dissolved sugars) made in the leaves to the rest of the plant for immediate use or for storage.
What is transpiration?
Transpiration is the loss of water from the plant.
List the four main things that affect transpiration.
How could you measure the rate of transpiration?
Measuring the uptake of water by a plant. This is because you can assume that water uptake by the plant is directly related to water loss by the leaves (transpiration)