infectious diseases in human

Question 1

diseases

Answer 1

condition that causes the body to function less effectively

Question 2

infectious diseases

Answer 2

-transmissible disease
-caused by disease causing organisms/pathogens

Question 3

non-infectious diseases

Answer 3

-not transmissible
-not caused by pathogens
-may be inherited or caused by factors like malnutrition, environmental [pollution etc] and lifestyle habits [excessive alcohol consumption, smoking etc]

Question 4

sign

Answer 4

can be observed or measured

Question 5

symptom

Answer 5

can be described or felt by the patient

Question 6

how do infectious diseases spread, elaborate

Answer 6

-respiratory droplets in the air; willy cough/sneeze got numerous tiny respirator droplets which may contain pathogens, poor billy breathe would get infected

-direct contact; bloodstream [break in skin], mucous membrane [membrane lining of the eye, nose, mouth], exchange of bodily fluids [eg. STIs like HIV], breastfeeding [eg. hepatitis B, syphilis]

-contaminated food and water; not handled properly/stored [cause food/water borne diseases]

Question 7

how to prevent the spread of infectious diseases

Answer 7

-practice good personal hygiene
-wear mask if sick
-practice hygienic food preparation and storage
-maintain clean water supply

Question 8

structure of bacterial cell

Answer 8

cell wall, cell membrane, ribosomes, DNA, cytoplasm, plasmid, flagellum

Question 9

structure of virus

Answer 9

genetic material [DNA or RNA], protein coat, may have additional lipid bilayer

Question 10

characteristics of virus

Answer 10

-does not have cellular structure
-does not grow, move, feed, respire or excrete
-enters a living cell which acts as a host for reproduction

Question 11

influenza virus [state the cause, signs and symptoms and how it is transmitted]

Answer 11

cause
-influenza virus

signs and symptoms
-high fever, headache, stuffy nose, cough, sore throat, muscle ache

how it is transmitted
-droplets in the air
-when a person touches an object/surface contaminated with the virus then touch their own mouth/nose/eye

Question 12

methods to reduce transmission of influenza virus/pneumococcal disease

Answer 12

-take influenza/pneumococcal vaccine
-avoid coming into close contact with people who have the flu
-if you are sick, cover mouth wear mask
-wash your hands with soap and water
-take antiviral drugs/antibiotics prescribed by dr if sick

Question 13

pneumococcal disease [state the cause, signs and symptoms and how it is transmitted]

Answer 13

cause
-pneumococcus bacteria

signs and symptoms
-fever, headache, vomiting, cough, chest pain, rapid breathing

how it is transmitted
-respiratory droplets

Question 14

vaccines

Answer 14

contains an agent that resembles a pathogen and prevents infectious diseases by stimulating WBC to quickly produce antibodies when pathogen invades

Question 15

how does vaccines work

Answer 15

-vaccine contains an agent that resembles a pathogen
-WBC recognises and binds to antigens on pathogen
-this stimulates WBC to produce antibodies that have a complementary shape to the pathogen
-WBC remain in the blood as memory immune cells
-when pathogen enters body, it can recognise and binds to the pathogens that causes infectious disease and mark them for destruction

Question 16

how does antibiotics work

Answer 16

-inhibit synthesis of bacterial cell wall; bacterial cell walls are weakened->water enters the cell by osmosis->cell expand and burst -> die

-inhibits cell membrane function; break up bacterial cell membrane-> cell no longer protected from its env->any substance can move into the cell, including harmful ones

-inhibits protein synthesis in ribosomes; antibiotics bind to ribosomes->ribosomes cannot take part in protein synthesis-> cell cannot grow

-inhibits enzyme action in cytoplasm; bacteria requires a vitamin (folic acid) for growth, antibiotic inhibit enzyme needed for synthesis of folic acid-> inhibit growth of bacteria

Question 17

antibiotic resistance

Answer 17

-overuse bacteria will naturally select for bacteria that genetically mutate and gain resistance to antibiotics
-the gained resistance give a selective advantage for bacteria survival and they will reproduce such that the subsequent generations will also inherit the antibiotic resistance gene