Module 4 Flashcards
Define the term parasite
- Lives in host
- Gains nutrition from host
- At expense of/harms host (causes disease)
Explain why the human boby’s primary defences do not prevent the entry of Plasmodium into the body
- Mosquito (vector) feeds on blood
- Mosquito pierces skin
Suggest why malaria is much more common in tropical areas than in other parts of the world
- Suitable climate for mosquito (vector)
- More mosquitos live there
- Relatively poor so methods of prevention less effective/ lack of education
Suggest two reasons why governments in parts of the world other than tropical areas, are also becoming increasingly concerned about malaria
- Global warming may result in spread to other parts of the world
- Increased movement of (infected) people
- (non-malaria) countries fund anti-malaria measures via international aid
- Resistance of parasite to drugs/ resistance of mosquito to insecticide
Suggest why erythrocytes that contain Plasmodium are more likely to be destroyed by phagocytosis than healthy erythrocytes
- (different) chemical that attract phagocytes
- cytokines/histamine/interleukin released
Describe the differences between globular and fibrous protein using haemoglobin and collagen as examples
GLOBULAR:
- ball (shaped)/ spherical
- hydrophilic (R-) groups/ regions on outside (of 3-D structure)/ hydrophobic (R-) groups/regions on inside
- form H-bonds with water
- soluble
- haemoglobin carrier/ transports O2/CO2
- haemoglobin contains prosthetic group/ haem/ Fe2+/ iron ion (to allow O2 to be carried)
- (polypeptide chains within) haemoglobin have tertiary strcuture (in a ball shape)
FIBROUS:
- linear/ long (chain)
- chains can form H-bonds with adjacent chains within molecule
- insoluble/ few hydrophilic groups
- strong/ provides strength
- have structural role
- collagen forms part of cartilage/connective tissue/ bronchi/ bronchioles
Describe how the structure of antibodies allows them to perform their function
- 2 light chains and 2 heavy chains / 4 polypeptide chains
- variable region allows binding/ attachement to antigen
- two variable regions allow binding of more than one (of the same) antigen
- variable region on different antibodies allow specificity to different antigens
- constant region allows recognition by/ attachment to/ binding to, (named) phagocytes
- hinge (region) allows flexibility
- disulfide, bonds/bridges, hold polypeptides/ light and heavy cains, together
Describe the process of agglutination
- clump/bind together, many pathogens
- (clump) too large, to enter (host) cell/ cross membrane
- increase likelihood of being consumed by (named) phagocyte/ more can be consumed by phagocyte at once
In a piece of school homework a student wrote:
‘Bacteria can evolve quickly and many are now immune to antibiotics’
Explain why the students use of the word immune was incorrect
- immunity involves/baceteria do not have, lymphocytes/ antibodies/ white blood cells/ an immune system/ memory cells/ plasma cells
- correct term is resistant
- bacteria are unicellular/ only multicellular organisms (can) have an immune system
Why are phagocytes described as a secondary defence?
(involved) after, pathogen, has entered the body
Why is the response involving phagocytes regarded as non-specific?
(phagocytes) able to digest/break down/ engulf/ target/ deal with, a range of/ many different, pathogens
Describe the process by which a pathogen is destroyed after it has become attached to the surface of a phagocyte
- (pathogen) engulfed/ enveloped/ surrounded by cytoplasm (of phagocyte)
- endocytosis/phagocytosis
- (formation) of phagosome/ phagocytic vacuole
- (phago) lysosomes
- (lysosomes/phagosomes) move towards/ fuse with (each other)
- (named) enzyme/ lysins/ hydrogen peroxide/ free radicals (in lysosomes)
- (pathogen) digested/broken down/ hydrolysed
- to amino acid/ sugar/ glucose/ glycerol/fatty acids
or unwanted products removed (by exocytosis) - cytoskeleton involvement in (endocytosis/ movement of vesicles)
Describe how TB is transmitted from one individual to another
- droplets (containing pathogen)
- (released by) coughing/sneezing
- inhaled by (uninfected individual)
Suggest reasons why incidence of TB is higher in low income groups
- overcrowded (living space)
- poorly ventilated (living space)
- poor diet/ malnourished
- poor health
- homelessness
- more likely to consume, meat/milk from infected cattle
- vaccination/medical treatment, more difficult to access
State features of malarial parasite that indicate that it is not a prokaryote
- Nuclues/ nuclei
- membrane bound organelles
- large ribosomes
- no cell wall
Describe how mosquitos transmits malarial parasite to a human
- (mosquito) is a vector
- Plasmodium/ parasite, present in (mosquito), saliva/ salivary gland
- infected mosquito, feeds on/bites, human
- Plasmodium/parasite passed (from saliva) to blood
Suggest reasons why people may be concerned about using insecticides
- Development of insecticide resistance
- might cause unintended health problems in humans
- might harm other/unintended species
- bioaccumulation/biomagnification
Suggest how the effects of insecticide use on a population of mosquitos could be measured and state the steps that should be taken in order to produce valid and reliable results
FIELD INVESTIGATION:
- (sampling) before and after insecticide treatment
- unbiased/ random, sampling of population
- example of sampling technique; sweep net, pond net, light trap
- (sampling in different, times/ weather
- large number of samples taken
- standardised sampling procedures
- preventing counting same individual more than once
- capture-recapture
- calculate mean/ calculate standard deviation/ apply statistical test
LABORATORY INVESTIGATION
- with and without insect exposure
- measuring mosquito survival/ count surviving mosquitos
- controlling one named key variable; exposure time/species of mosquito/stage of mosquito life cycle/ sex of mosquito/ insecticide type
- using a range of insecticide concentrations
- replicates
- calculate mean/ standard deviation/ apply statistical test
- T
- T
- B
- both
- T
Describe the changes in antibody concentration that occur in the patients blood during the primary response
- no antibodies detected before 4 days/antibodies appear at 4 days
- increase then decrease
- figures
- decrease = less steep than increase
- antibody concentration returns to zero at 27 days
Function of the hinge region of an antibody
- flexibility/ binding of more than one antigen
Function of the constant region on an antibody
- attachment/ binding to phagocytes
Function of the variable region on an antibody
- binding/ attachment to antigens
State two differences between primary and secondary immune response
- secondary response, starts earlier/ has shorter delay before resonse
- secondary response, more rapid/ faster
- secondary response, higher/produces more antibodies
