First line of defence and plants response to pathogens

Question 1

physical barriers in plants

Answer 1

spines, thorns, tough tissue, thick waxy cuticle, sticky resins, closing of stomata, formation of galls

Question 2

chemical barriers of plants

Answer 2

production of chemicals that can be toxic or repellent in nature, can be produced pre-emptively or in response to a pathogen

Question 3

how to plants stop a pathogen from spreading between cells

Answer 3

plant cell produces polysaccharides that can sttrenthen cell walls, making it harder for the next pathogen to enter the cell, also produce plasmodesmata preventing pathogens from migrating to uninfected cells

Question 4

how do pathogens infect a plant

Answer 4

some bind directly to the plant receptors in the cell membrane, other break down molecules within the plant cell (via enzymes) and then bind to the plant receptors

Question 5

when plants detect a pathogen they do what

Answer 5

trigger a signal transduction inside the plant cell, response might be to turn on and express certain genes inside the cell which results a variety of molecules being produced that can kill a variety of pathogens, some chemicals travel through plasmodestmata serving as alarm signals for uninfected cells, plant may form hypersensitive response

Question 6

hypersenstive response in plant

Answer 6

prevents spread of patjogen by causing cells to undergo apoptosis, e.g resulting in dead tissue, lesions or leaves dropping off

Question 7

what are the two types of immunity in animals

Answer 7

innate immune response (1st and 2nd line of defence) and adaptive immune response (3rd line of defence)

Question 8

what are the characteristics of the innate immune response

Answer 8

non-specifc - same no matter the pathogen and how many times the body has been exposed to the pathigen, protects the body without a need for a lot of prep, contains 1st and 2nd line

Question 9

what are the three types of barriers in the first line of defence

Answer 9

chemical, physical amd microbiological

Question 10

what are the barriers inn the first line of defence

Answer 10

intact skin, ciliated mucous membranes, tears, saliva, stomach and vaginal acidity , urine, expulsion reflexes, normal flora

Question 11

how does intact skin provide a barrier

Answer 11

impermeable thick barrier, all cells on the surface of the body are dead so a pathogen can’t infect them (physical) sweat glands and sebaceous glands secrete sebum, skin is slightly acidic (chemical) normal flora on skin (microbiological)

Question 12

sebum

Answer 12

thick, oily substance that slows the growth of bacteria

Question 13

how do tears provide a barrier

Answer 13

wash away bacteria (physical) and contain lysozomes which cause pathogens ike bacteria to be broken down (chemical)

Question 14

how does saliva act as a barrier

Answer 14

can wash away pathogens with food (physical) and contain enzymes to destroy ppathogens such as bacteria (chemical)

Question 15

how does stomach acidity provide a barrier

Answer 15

highly acidic environment can denature the enzymes of alot of pathogens, digestive enzymes can also damage pathogens

Question 16

how does blood clotting provide a barrier

Answer 16

causes barrier to stop spread of pathogen, prevent entry of pathogen

Question 17

how does urine provide a barrier

Answer 17

slightly acidic, frequently flushed out of bladder

Question 18

expulsion reflexes examples and use

Answer 18

vomiting diarrhoea which remove toxins or pathogenic agents from body

Question 19

how does gut flora provide a barrier

Answer 19

prevent other species of bacteria by outcompeting them for nutrients, adhesion sites annd secrete cehmicals that prevent the growth of pathogenic bacteria

Question 20

how do ciliated mucous membranes provide a barrier

Answer 20

sticky mucous traps pathogens (physical), contains enzyme that breaks down bacteria (chemical), pathogens and substances are swept out of airways by cillia which line the trachea (physical)