Defence Against Disease

• AProteins
• BPhospholipids
• CCarbohydrates
• DNucleic acids

• AIncreased number of T-lymphocytes.
• BLarge numbers of antibodies are released.
• CLarge numbers of antigens are released.
• DIncreased number of B-lymphocytes.

• ASexual intercourse
• BBlood donation
• CSharing of needles used by intravenous drug users
• DFrom mother to child across the placenta
• EAirborne droplets from coughing

True or false?

True or false?

• Phagocyte membrane extends out
• Endocytosis
• Vacuole formation
• Enzymatic digestion

• AObserved: Resistance to an antibiotic appears soon after an antibiotic is first used. Explanation: Bacteria respond to a new antibiotic by developing resistance.
• BObserved: Resistance to an antibiotic appears soon after an antibiotic is first used. Explanation: Bacteria with alleles that provide resistance to the antibiotic survive treatment and pass on their alleles.
• CObserved: Bacteria with alleles that provide resistance to the antibiotic survive treatment and pass on their alleles. Explanation: The frequency of resistant alleles increases in a bacterial population.
• DObserved: Antibiotic resistance in bacteria is on the increase in hospitals. Explanation: Patients in hospitals are more susceptible to infection than the general population.

• AA disease that can cross the species barrier from animal to human.
• BA disease that only affects humans.
• CA disease caused by a virus that infects only birds.
• DA disease that is transmitted by a vector.

• AIt occurs immediately upon first exposure to an antigen and produces a large amount of antibodies.
• BIt occurs slowly upon first exposure to an antigen and leads to the production of memory cells.
• CIt occurs rapidly upon second exposure to an antigen and produces a large amount of antibodies.
• DIt is a non-specific response involving phagocytes.

• AProthrombin → Thrombin → Fibrin → Fibrinogen
• BClotting factors → Thrombin → Fibrinogen → Fibrin
• CFibrin → Fibrinogen → Thrombin → Clotting factors
• DClotting factors → Thrombin → Fibrin → Fibrinogen

• APhagocytes
• BAntibody production by plasma cells
• CSkin
• DMucous membranes

• AAvoiding prescription of antibiotics for non-serious or non-bacterial infections
• BMaintaining high standards of hygiene in the hospital environment
• CMinimising use of antibiotics for routine treatment of animals in agriculture
• DDevelopment of new types of antibiotic
• EIncreasing the use of broad-spectrum antibiotics

True or false?

• AThey engulf and digest pathogens.
• BThey produce antibodies immediately upon first exposure to an antigen.
• CThey remain in the blood and allow a faster immune response to the same pathogen in the future.
• DThey present antigens to T-helper cells.

• APeople infected with HIV will always show symptoms immediately.
• BPeople infected with HIV can be completely cured with antibiotics.
• CPeople infected with HIV may live for many years after infection.
• DHIV is transmitted by a vector.

• AT-helper cell activation → B cell activation → clonal expansion → antibody production
• BB cell activation → T-helper cell activation → clonal expansion → antibody production
• CClonal expansion → T-helper cell activation → B cell activation → antibody production
• DAntibody production → B cell activation → T-helper cell activation → clonal expansion

• AImmunity acquired through natural infection.
• BProtection of the entire population when a large enough percentage is vaccinated.
• CImmunity passed from mother to child.
• DImmunity produced by antibiotics.

• AViruses are too small for antibiotics to target.
• BViruses have no metabolism or cell structure and use host cell mechanisms.
• CViruses have a protein coat that antibiotics cannot penetrate.
• DViruses are living cells that are resistant to antibiotics.

• ATuberculosis
• BAthlete's foot
• CMalaria
• DCancer

• AThey produce antibodies.
• BThey engulf pathogens.
• CThey activate B cells and stimulate them to divide.
• DThey directly kill infected cells.

• AIt is specific to a particular antigen.
• BIt responds the same way to any non-self antigen.
• CIt produces memory cells.
• DIt involves antibody production by plasma cells.

• AVaccines contain live pathogens that cause disease.
• BVaccines induce immunity by introducing antigens without causing disease.
• CVaccines provide immediate immunity without memory cells.
• DVaccines are only effective against bacterial diseases.

True or false?

• ATo engulf pathogens.
• BTo directly kill pathogens.
• CTo bind to specific antigens and neutralise or agglutinate pathogens.
• DTo produce memory cells.

• AIt is slower and produces fewer antibodies than the primary response.
• BIt is faster and produces more antibodies than the primary response.
• CIt occurs only after vaccination.
• DIt is non-specific.

• AMalaria
• BCOVID-19
• CCholera
• DAthlete's foot

• Clotting factors stimulate the release of thrombin
• Thrombin catalyses the conversion of fibrinogen to fibrin
• Fibrin forms a mesh that traps platelets and blood cells
• Exposure to air hardens the mesh to form a scab

• ANeutralisation of toxins
• BAgglutination of bacteria
• CIncreased susceptibility to phagocytosis
• DDirect destruction of viruses by enzymes
• EProduction of memory cells

• AAntigen presentation → T-helper activation → B-cell activation → clonal expansion → antibody production
• BB-cell activation → T-helper activation → antigen presentation → clonal expansion → antibody production
• CClonal expansion → antigen presentation → T-helper activation → B-cell activation → antibody production
• DAntigen presentation → B-cell activation → T-helper activation → clonal expansion → antibody production

• ASexual intercourse
• BSharing needles for intravenous drug use
• CFrom mother to child across the placenta
• DCasual contact such as hugging
• EBlood donation

Thrombin catalyses the conversion of the soluble protein ____ into ____, which is insoluble.

HIV is a ____ virus, meaning it uses the enzyme reverse transcriptase to produce DNA from its RNA genome.

Mucus contains ____ enzymes which have antibacterial properties.

Zoonotic diseases are those which can cross the species barrier from ____ to ____.

• A168.3 %
• B201.9 %
• C185.1 %
• D151.5 %

• A-47.5 %
• B-52.8 %
• C-58.1 %
• D-42.2 %

• A151.5 %
• B201.9 %
• C168.3 %
• D185.1 %

• A47.5 %
• B58.1 %
• C63.4 %
• D52.8 %