Biology Paper 1 Flashcards
What are chromosomes made of?
DNA molecules
Each chromosomes carries a large number of genes
What does the nucleus of a cell contain?
Chromosomes
In body cells why are the chromosomes normally found in quadrets?
They arn’t they are found in pairs
What is the cell cycle?
A series of stages of which a cell divides in two, where genetic info is doubled into two identical cells
What happens before mitosis? (include this in an answer about mitisis)
1st stage)
The cell increases in size
The subcelluar structures (such as mitrochondria) divide
The DNA is then duplicated which formes an X- shaped chromosome.
What is special about the X-shaped chromosome?
Each arm is identical to the other so that both daughter cells will be geneticly identical
What are the stages of mitosis
Second stage)
The chromosomes line up in the middle of the cell and cell fibres pull them apart. A membrane then formes around each set of chromosomes (this is the nuclei of each new daughter cell
Third stage)
Finaly the cytoplasm and the cell membrane divides
How similar are two daughter cells after mitosis?
They are geneticly identical also with the parent cell
Where do you find a lot of mitosis?
In multicelluar organisms as it is important to replace dead/old cells ect
What is a stem cell?
An undifferentiated cell of an organism which still has the ability to specilise
What can stem cells from embryos do?
They can be cloned and can be made to differentiate (specilise) in almost any cell
What can stem cells from adults do?
What about from bone marrow?
They have alreay differentialated and can therefore only specilise to be where they were taken from
(From spec) they can form many different types of cells including blood cells
What can stem cells from the meristem do?
They can differentiate into any plant cell throught the life of the plant
(It never looses the ability to differentiate)
What may stem cell’s be able to treat?
Diabetes, paralysis
What happens in therapeutic cloning?
An embryo is produced with the same genes as the patient. These cells may be used for medical treatment as they won’t be rejected by the patients body
What are the disadvantages of stem cell treatments?
There could be a risk of catching a virus if the cells grown in the lab got contaminated
It may go against religious and ethical views
What may a stem cell from a meristem be used for?
To produce a clone of the plant which it came from quickly and economicly
Rare species may be cloned to protect them from going extinct
Crops and plants with special features may be cloned (eg needed for making medicine) can be made quickly
(My idea) may be used for economic purposes pf mass trowing of cash crops
What is an organ system?
Give an example?
A group of organs that work together to perform a specific function
Digestive system
Describe an enzyme?
It has an active side (which is specific to a specific type of molecule) which binds to the molecule (a substrate) and causes it to break up into different bits
What happens to enzymes as temprature increases?
The enzyme will have more kinetic eneergy and therefore will move faster which may lead to an increase in the rate if reaction however if the temprature increases further (about 40º) then the enzyme’s active side may become deformed. This means that the enzyme has becoem denatured and it will now no longer be able to catalys reactions
What is coronary heart disease?
Coronary heart disease is when layers of fatty acids build up insode the coronary arteries, narrowing them. This reduces blood flow through the coronary arteries resulting to a lack of blood and oxygen for the heart muscle
What do stents do?
They are a wired cage that can be inserted into a valve. They will keep the valve wide open to allow blood to go through
What is statin?
Whta does it do?
A drug
It reduced blood cholesterol which slows down the build up of fatty acids in the coronary arteries
What are falty valves?
Valves that can’t open fully or they may leak blood back through them
What may faulty valves lead to?
This could lead to a backflow of blood which may mean that other parts of the body arn’t getting enough blood as the blood circulation is less efficent
How may a faulty valve be fixed?
Biological or mechanical methods such as transplants from a pig or a transplant of a mechanical man made valve
How may heart failure be fixed?
Through transplant
This may also be done for lungs
It could be a transplant of a natual heart from someone who recently died or an mechanical heart
What may a mechanical heart be used for?
To keep someone wlove if a donar heart cannot be found
To help the heart to rest (being used as an aid to recovery)
What are the disadvantages of a mechanical heart?
They can’t be relied on forever. They can only keep a patient alive for a certian amount of time
What are the advantages of treating cardiovascalin diseased using drugs?
They are effective
They increase the amount of “good” cholesteral in your blood
Some studdies show that stain may also help prevent some other diseases
What are the advantages of treating cardiovascalin diseased using transplants
It is effective
You will be getting a new healthy heart.
You only need to do it once (hopefuly)
What are the advantages of treating cardiovascalin diseased using mechanical devices?
It’s effective
Only have to do it once (hopefuly)
How may different types of diseases interact with each other?
A phycical disease that prohibits movement could cause a metal disease like depression
A virus could trigger cancer
Problems woth the immune system may mean that a person is more lilkley to suffer from an infectios disease
Immune reactions may cause an allergie such as sking rashes or asthma
What is health?
The metal and phycicals wellbeing of a person
What may effect a persons health?
Diet Lifestyle Stress Non communical diseases Communical diseases
What is the lock and key theory?
The substrate binds to the active side of an enzyme which then breaks it into smaller pieces
