immunity

Question 1

what is the structure of bacteria?

Answer 1

• single celled prokaryotes
• cytoplasm that lacks membrane-bound organelles
• no nucleus - single circular bacterial chromosome (free in cytoplasm)
• cell wall contains glycoprotein peptidoglycan
• loops of DNA - plasmids

Question 2

what is the function of capsules in a bacteria cell?

Answer 2

protect bacteria from drying out and from attack by cells of the immune system of the host organism

Question 3

what is the function of the flagellum in a bacteria cell?

Answer 3

for movement

Question 4

what is the function of pili in bacteria cells?

Answer 4

enable the bacteria to attach to other cells or surfaces

Question 5

what is the structure of viruses?

Answer 5

• non cellular infectious particles
• nucleic acid core
• protein coat ‘capsid’
• do not have plasma membrane, cytoplasm or ribosomes
• envelope (outer layer)
• proteins inside capsid
• attachment proteins

Question 6

what are infectious diseases caused by?

Answer 6

pathogens

Question 6

what is the function of attachment proteins?

Answer 6

enables virus to attach itself to a host cell

Question 7

what are types of pathogens?

Answer 7

bacteria, some fungi and all viruses

Question 8

what are T cells?

Answer 8

type of white blood cell involved with specific immune response

Question 9

when are T cells activated?

Answer 9

when they encounter and bind to their specific antigen on the surface of an antigen presenting cell

Question 10

what do T helper cells do?

Answer 10

release chemical signalling molecules that help to activate B cells

Question 11

what do T killer cells do?

Answer 11

bind to and destroy infected cells displaying the relevant specific antigen

Question 12

what do T memory cells do?

Answer 12

they remain in the blood and enable a faster specific immune response if the same pathogen is encountered again in the future

Question 13

what are B cells?

Answer 13

second type of white blood fell in the specific immune response

Question 14

where are B cells found?

Answer 14

bone marrow

Question 15

what do B cells have on their cell surface membrane?

Answer 15

antibody receptors

Question 16

when do B cells bind to the antigen?

Answer 16

if the corresponding antigen enters the body, B cells with the correct cell surface antibodies recognise and bind to it —-> antigen - antibody complex

Question 17

how does the B cell divide?

Answer 17

mitosis

Question 18

what does the cell division of the B cells produce?

Answer 18

many clones of the original activated B cell

Question 19

what are the two types of B cells?

Answer 19

• memory cells
• plasma cells

Question 20

function of plasma cells?

Answer 20

produce specific antibodies to combat non-self antigens

Question 21

function of memory cells?

Answer 21

remain in blood to allow a faster immune response to the same pathogen in the future

Question 22

what are the entry routes of pathogens?

Answer 22

• broken skin
• the digestive system
• the respiratory system
• mucosal surfaces

Question 23

what are barriers to infection?

Answer 23

• skin
• microorganisms of gut and skin
• stomach acid
• lysozyme

Question 24

how does stomach acid create a barrier for infection?

Answer 24

hydrochloric acid creates an acidic environment that is unfavourable to bacteria