IB Biology HL: C3.2 Defense Against Disease

phagocyte

white blood cells that engulfs and digest pathogens

pathogen

any organism (or virus) that cause disease

plasma cell

produce many copies of the specific antibody to help prevent pathogen from surviving; B-cell under mitosis to form →

memory cell

B-cells undergo mitosis to form → . remain in bloodstream after infection left, ensures a rapid response if pathogen/antigen encountered again later. results in long term immunity against pathogens with that antigen

zoonosis

infectious diseases that can transfer from other species to humans. varied modes of transmission

herd immunity

the resistance to the spread of an infectious disease within a population. based on pre-existing immunity of high proportion of individuals, as a result of previous infection or vaccination

pandemic

an epidemic that has spread over multiple countries or continents

epidemic

when an infectious disease affects a large number of people within a community, population, or region

what are vaccines?

it is either antigens or nucleic acids (DNA or RNA sequence) that code for an antigen

how do vaccines work?

stimulate adaptive immune response to a particular disease causing pathogen (the goal is to artificially (body still does the work) cause the body to do the same thing it would normally do if it was exposed to a pathogen) causes body to form memory cells to fight with if infection comes back

does getting a vaccine mean you won’t get infected?

NO, it just reduces the risk and the possible severity

Do antibiotics work on BACTERIA?

YES, it can kill bacteria inside the body without causing harm to human cells. targets the process of bacterial DNA replication, transcription, translation, ribosome function, and cell wall formation

do antibiotics work on VIRUSES?

NO, viruses use the chemical process of the host, instead of having a metabolism of their own. it is inappropriate for doctors to prescribe antibiotics to treat viral infections and it contributes to the overuse of antibiotics and increases in antibiotic resistance in bacteria

do antibiotics work on HUMAN CELLS?

NO, because cell function would be harmed

what does HIV cause?

AIDS

what cell is attacked in HIV?

infects and kills CD4 cells (HELPER T LYMPHOCYTES), this limits immune system’s ability to produce antibodies and fight infections.

what are the transmissions of HIV?

SHARING OF BODILY FLUIDS

1. vaginal or anal sexual intercourse

2. blood transfusion of infected blood/blood products

3. sharing of hypodermic needles

4. across placenta from mother to fetus

5. from mother to baby during birth process through cut or tears

6. breastmilk

what was the specific viral cause of COVID-19?

zoonoses: first animal to human (bats)

what is the transmission of COIVD-19?

human to human (primarily through air)

when would you use percent difference?

used to COMPARE 2 values

percent difference formula

=(final -initial) / average x 100

when would you use percent change?

to measure CHANGE over time

Percent Change formula

= (final -initial) / initial. x100

what are the BENEFITS of vaccines?

• protection for individual from infection and its harmful effects

• protection for a community through herd immunity

• total eradication of a disease (ie. small pox)

• reduced economic burden of healthcare for sick

• prevention of pandemics and epidemics with sufficient cooperation

what are the RISKS of vaccines?

• some people are allergic to them

• mercury was once used as a preservative

• some multiple-jabs may overload the immune system of some people

• there are often minor side effects

what are the 2 clotting reactions?

(reactant) ——-(catalyst)——> (product)

1. prothrombin ———-prothrombinase——> thrombin

2. fibrinogen ———-thrombin——> fibrin

what are some characteristics of primary, innate, non-specific defense mechanisms?

• physical and chemical barriers, and phagocytes

• does NOT change over lifetime

• a non-specific response to abroad range of pathogens

the 4 different primary, innate, non-specific defense mechanisms?

1. phagocyte

2. skin

3. mucus membrane

4. blood clotting

skin

physical barrier which prevents pathogens entering the body (chemical barrier). include sebaceous glands and mutualistic bacteria

sebaceous glands (skin)

in skin, secrete lactic acid and fatty acids which creates acidic conditions → prevents growth of most pathogenic bacteria

mutualistic bateria (skin)

prevent growth of pathogens (competitive exclusion)

mucus membrane

soft areas of skin that are kept soft with mucus, do NOT form a strong physical barrier.

but they do produce lysosomes enzymes. pathogens become trapped in mucus lysosome kill bacteria by damaging the bacteria cell wall

blood clotting

prevents loss of blood and entry of pathogens. creates scab