Bio content paper 1 Flashcards
What is blood and what are its components?
a tissue consisting of plasma, in which the red blood cells, white blood cells and platelets are suspended.
What is the function of the blood plasma?
Mostly water with dissolved substances within it (e.g. distributing carbon dioxide, digested food molecules, urea and hormones; distributing heat)
Makes up 55% of the blood compared to other components
What is the function of the red blood cell?
Transports oxygen for use in aerobic respiration to release energy
What is the function of the white blood cell?
Ingests pathogens and produces antibodies to kill/prevent disease
What s the function of the plate
stop bleeding by blood clotting
Where in the lungs does gaseous exchange take place?
The alveoli
How are red blood cells adapted to their function?
- Contain reg pigment haemoglobin (gives colour) - which binds to oxygen to make oxyhemoglobin to carry oxygen to cells
- They have no nucleus - so they can pack in more haemoglobin.
- They are small and flexible so that they can fit through narrow blood capillaries.
- They have a biconcave shape - to maximise their surface area for oxygen absorption.
- They are thin, so there is only a short distance for the oxygen to diffuse to reach the centre of the cell
How are white blood cells adapted to their function?
Part of immune system
Phagocytes - engulf and destroy pathogens that enter the blood, by the process of phagocytosis. They have an elongated shape that can change and that allows them to engulf pathogens easier
Lymphocytes - produce soluble proteins called antibodies which bind to the protein antigen on pathogens, killing them
How are platelets adapted to their function?
- they have proteins on their surface that enable them to stick to breaks in a blood vessel and clump together (forming scab at wound to prevent infection/reduce blood loss)
- they secrete proteins that result in a series of chemical reactions that make blood clot, which plugs a wound
They are cell fragments
Label the blood
Please note the size of different components and that all other components are dissolved within the blood plasma
How are cancers caused?
Cancer is caused as a result of mutations in the DNA of cells that lead to uncontrolled growth and division – this can result in the formation of a tumour (a mass of cells)
What are benign tumours?
growths of abnormal cells which are contained in one area, usually within a membrane (no direct risk of death)
they do not invade other parts of the body
THEY ARE NOT CANCERS
What are malignant tumour cells?
They invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours - risk of death
THEY ARE CANCERS
What are some examples of lifestyle risk factors of cancers?
- obesity (bowel, liver, kidney)
- smoking (lung, mouth, throat, stomach)
- exposure to UV radiation (skin)
- viral infection (cervical, liver)
As well as lifestyle risk factors of cancers, there are (…) risk factors
genetic (e.g. faulty genes)
What are antibiotics?
They are medicines that help to cure bacterial disease by killing infective bacteria inside the body
What is important to keep in mind when treating bacterial diseases with antibiotics?
It is important that specific bacteria should be treated by specific antibiotics
How antibiotics been useful since their discovery?
The use of antibiotics has greatly reduced deaths from infectious bacterial diseases
What is currently an issue that is concern about the use of antibiotics?
The (recent) emergence of strains resistant to antibiotics is of great concern
Why can’t antibiotics be used to treat viruses (e.g. Measles)?
Antibiotics cannot kill viral pathogens.
What are painkillers?
They are used to treat the symptoms of disease but do not kill pathogens
this may be similar for other medicines
Why is it difficult to develop drugs that kill viruses?
Because the drugs also (often) damage the body’s tissues.
Where were drugs traditionally extracted from?
from plants and microorganisms
Where does digitalis come from??
foxgloves
What type of drug is digitalis?
heart drug (treats heart disease)
Where does aspirin come from?
willow
What type of drug is aspirin?
a painkiller
Who discovered penicillin?
Alexander Fleming
Where did penicillin come from (when it was discovered)?
the Penicillium mould
What type of drug is penicillin?
an antibiotic
How are most new drugs synthesised?
by chemists in the pharmaceutical industry
Where may the starting point for the discovery of drugs still be today?
a chemical extracted from a plant
Why do new medical drugs have to be tested and trailed before being used?
to check that they are safe and effective
What are new drugs extensively tested for?
for toxicity, efficacy and dose
Just need to state base terms, but likely in exam question, you would have to expand
What are the stages to the development of new drugs?
- pre-clinical testing
- clinical testing (healthy volunteers)
- clinical testing (patients)
- production
What is pre-clinical testing?
testing done in a laboratory using cells, tissues and live animals (e.g. mice)
In clinical testing, are healthy volunteers or patients tested first? Why is this?
healthy volunteers
as the effects of a drug (e.g. too high toxicity/dose) could be a lot more damaging to an ill patient
What is toxicity?
how safe the drug is/what the side effects are
What is dose?
how much of the drug should be taken and how often
What is efficacy?
whether the drug works
What sorts of doses of the drug are given at the start of the clinical trial?
Very low doses
If the drug is found to be safe, what happens next?
further clinical trials are carried out to find the optimum dose for the drug.
What is a placebo, and why is it used in clinical trials?
Placebo - a substance that looks like the real drug but doesn’t do anything
They are used to make sure the drug actually works, and people don’t just think it does
What is a double-blind trial and why is it used?
When neither the doctors or the volunteers know who is receiving the real drug and who is receiving the placebo
to avoid bias
The results of testing and trials are only published when?
after scrutiny by peer review
Describe what testing must happen before a new drug can be distributed? (6 marks)
- pre-clinical trials (in lab) of new drug on cells/tissues/animals
- to test toxicity, dosage and efficacy
- to monitor safety/side effects
- and only then do trials to find the optimum dosage and test for efficacy
- double blind trial and use of placebo
- which does not contain new drug (only replicates appearance)
- random allocation of patients to groups
- so no one knows who has placebo or new drug (not researches nor volunteers/patients know)
- to make sure drug actually works
- peer review of data
- to avoid false claims
- manufactured and distributed only after this
During exercise the human body reacts to the (…) for energy.
increased demand
3 things
What increases during exercise?
- heart rate
- breathing rate
- breath volume
Why do the heart rate, breathing rate and breath volume increase during exercise?
to supply the muscles with more oxygenated blood
What happens if insufficient oxygen is supplied to the body?
If insufficient oxygen is supplied, anaerobic respiration takes place in muscles.
The incomplete oxidation of glucose causes a build up of lactic acid and creates an oxygen debt.
During long periods of vigorous activity muscles become fatigued and stop contracting efficiently due to the lactic acid build up.
What is oxygen debt?
the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells
From where to where is lactic acid transported to be converted back to glucose?
Blood flowing through the muscles transports the lactic acid to the liver where it is converted back into glucose