Stuff I forget Flashcards
What are 3 differences between mammals and birds?
-birds have feathers, wings and 2 legs
Where would you find stem cells in the plant?
meristem (tips of roots and shoots)
What part of the neurone is long and what insulates it?
- axon
- insulated by myelin sheath
What is meant by ‘hormone’?
-chemical messengers carried by blood
Why is it important that homeostasis is maintained?
metabolism only operates in a narrow range of temperatures and pH and also needs nutrients and water in the correct amounts
What is negative feedback?
any change in from INTERNAL OPTIMAL conditions, causes the body to compensate by causing an opposing change
What sort of tissue is the Iris?
It is a muscle
Do light waves continue in the same direction in the light?
no, the cornea refracts the light
What happens if PROTEIN is present in the urine?
problems with ULTRAFILTRATION
What gland releases ADH?
pituitary gland
What does the collecting duct do?
- carries urine to the ureter
- some water is selectively reabsorbed here
What does benedict’s test do?
Test for glucose
Why does the tubule have a rich blood supply?
As SELECTIVE REABSORPTION happens here
Why does a dialysis machine need ideal concentrations of dissolved substances?
- contains equal concentration of glucose and salts that should not be removed from the blood (no net diffusion)
- It contains no urea and so urea will diffuse from a high concentration in the blood out into the dialysis fluid which is then disposed of
Why do dialysis and blood need to flow counter current each other?
to maintain a concentration gradient for diffusion of urea across the whole membrane
What immunoussay?
- diagnosis of diseases such as HIV, Chlamydia and Malaria
- using radioactive labels of fluorescent dyes ATTATCHED to monoclonal antibodies to attach to specific antigens
How could you tell how EXTENSIVE a malaria infection was?
-use monoclonal antibodies to detect plasmodium
What organ produces Lymphocytes B that make antibodies?
The spleen
How can monoclonal antibodies treat cancer?
- diagnose tumours using tumour markers
- stop cancer growth
- directly deliver drugs to treat tumour
- encourage the immune system to attack the tumour
What is the makeup of a virus?
DNA and a protein coat
Why is a virus not considered a living cell?
It cannot reproduce alone
Why do you need a vaccine regularly?
- as virus mutates, DIFFERENT antigens
- DIFFERENT antibodies needed
What do white blood cells to combat microbes?
- Phagocytes engulf microbes
- lymphocytes produce antibodies
- lymphocytes produce antitoxins which counteract toxins released by microbes
Why do we seal the petri dish with tape?
-to prevent contamination by bacteria
What is the process when waster products are removed by the kidney?
Excretion
Why is it important to avoid blood clot during dialysis?
prevent blockage
How do LYMPHOCYTES kill microbes?
- A lymphocytes recognises the antigen of an invading organism
- The antigen on the foreign cell CAUSES lymphocyte to MULTIPLY into clone cells
- then they SECRETE a lot of antibodies SPECIFIC to the antigen into the BLOODSTREAM
- The antibodies attach to the antigens on the microbes
- kill them for them or allow them to be engulfed by pathogens.
How does a vaccine produce memory cells?
the vaccine causes the IMMUNE SYSTEM to produce COMPLEMANTARY antibodies
- The antibodies target the antigen and ATTACH THEMSELVES to it in order to create memory cells.
- These will quickly respond to the antigen if it is encountered again
How do you have immunity after a vaccine?
- (After an antigen is encountered) memory cells REMAIN in the body
- Produced QUICKLY , LARGER numbers of antibodies if the same antigen is encountered again
- (hopefully destroying microbes BEFORE SYMPTOMS are felt) THIS IS IMMUNITY
3 Arguments AGAINST animal testing?
- Animals are killed or kept in captivity
- it is very expensive
- some substances tested may never be used for anything useful
What is the process of developing new medicines?
- tested using computer models and skin cells grown using human stem cells in the laboratory.
- tested on animals
- tested on healthy volunteers to check that they are safe.
What are 4 uses of monoclonal antibodies?
• diagnosis of diseases including Chlamydia and HIV
• tissue typing for transplants
• supporting chemotherapy for cancers
- Pregnancy testing
How are MONOCLONAL antibodies produced?
1-An antigen is injected into a mouse.
2-The mouse NATURALLY produces lymphocytes, which produce antibodies SPECIFIC to the antigen.
3- Spleen cells are fused with human cancerous white blood cells (MYELOMA CELLS) to form hybridoma cells which DIVIDE INDEFINITELY.
5-These hybridoma cells DIVIDE and produce MILLIONS of monoclonal antibodies SPECIFIC to the original antigen.
What is Continuous variation?
Controlled by more than one gene and environmental factors such as height and weight.
What is discontinuous variation?
Usually controlled by one gene
- so individuals fit clearly into discrete groups such as eye
colour, blood type.
What is variation caused by?
- Genetic factors: characteristics that are caused by genes, inherited from parental DNA
- Environmental Factors : characteristics that change due to the environment
What does cystic fibrosis do?
- a genetically inherited disease
- causes thick sticky mucus that block bronchioles in the lungs
What happens if environmental change is too quick?
If environmental change is too quick for species to adapt by natural selection extinction
may occur.
What were the aims oh the Human Genome Project?
- working out the order or sequence of all the three billion base pairs in the human genome
- identifying all the genes
- developing faster methods for sequencing DNA
How will the Human Genome Project help medicine?
allow scientists to develop new ways of treating or diagnosing illnesses, especially genetic disorders and cancer
What is an alien species?
An organism introduced into a country in which it does not normally live.
What are the steps of genetic profiling
- Cutting DNA into pieces
- which are then separated into bands
What do the order of bases do?
forms a code for making proteins
What does the triplet code do?
Each triplet code identifies for a particular amino acid.
-amino acids link together to form proteins
What is a disadvantage of genetic Profiling?
- ownership issues
- privacy issues
