communicable diseases - biology revision

Question 1

what is the definition of health from the WHO (world health organisation)?

Answer 1

health is a state of complete physical, mental and social wellbeing and not merely the absence of disease or infirmity.

Question 2

what are communicable diseases?

Answer 2

• can be passed from one person to another
• caused by pathogens
• most common in underdeveloped countries
• develops quickly
• medication often needed
• such as chicken pox, malaria, flu, ebola, measles, mumps

Question 3

what are non-communicable diseases?

Answer 3

• cannot be passed from one person to another
• caused by lifestyle
• more common in developed countries
• often chronic, lasts a long time, progresses slowly
• treated with lifestyle changes
• examples are cardiovascular disease, diabetes and non infectious diseases in the respiratory system

Question 4

what is a pathogen?

Answer 4

a disease causing organsim

Question 5

what are the four different pathogens?

Answer 5

• bacteria
• viruses
• fungi
• protist

Question 6

what are animals, plants, fungi and protists?

Answer 6

eukaryotic cells, meaning they have nucleuses

Question 7

what are the cell structures and their functions in a eukaryotic cells?

Answer 7

cell membrane - controls which substances can enter and leave the cell

cytoplasm - where chemical reactions occur

mitochondria - where aerobic respiration occurs

ribosomes - protein synthesis occurs

nucleus - contains DNA which controls cell activity

Question 8

what are the cell structures and functions in a prokaryotic cell?

Answer 8

cell membranes - controls which substances can enter and leave the cell

cytoplasm - where chemical reactions occur

mitochondria - where aerobic respiration occurs

ribosomes - protein synthesis occurs

nucleus - contains DNA which controls cell activity

cell wall - protects the cell

plasmid - circular DNA structures

pila - hair like structures which attach to other bacterial cells

capsules - protects the cell when its engulfed, helps keep its moisture and helps to stick it to surfaces and nutrients

flagella - helps the cell swim

Question 9

what are bacteria cells?

Answer 9

prokaryotic cells, which means they have no nucleus

Question 10

what pathogen isn’t a cell?

Answer 10

viruses

Question 11

describe a bacteria cell

Answer 11

includes cell wall, cell membrane, DNA and cytoplasm

• very small cells which reproduce rapidly in your body
• can make you feel ill as they produce toxins that damage your cells and tissues

Question 12

describe viruses

Answer 12

• only contain dna ( sometimes)
• they live in cells and reproduce rapidly
• eventually burst, releasing the virus, damaging the cell and making you feel ill

Question 13

describe protists

Answer 13

• cell wall (sometimes), cell membrane, nucleus, DNA, chloroplasts (sometimes) and cytoplasm
• eukaryotic cells
• some are parasites which live on an organism causing damage
• they are transferred by something that doesn’t get the disease e.g. an insect

Question 14

describe fungi

Answer 14

• contain cell wall, cell membrane, nucleus, cytoplasm
• some have a body made up of thread like structures which penetrate the skin and the surface of plants causing disease

Question 15

what are the defence barriers against disease in the body?

Answer 15

eyes - tears contain an enzyme called lysozyme which destroys bacteria

nostrils - contains hairs and mucus which trap organisms

air passages - contain cilia which remove disease organisms trapped in mucus

stomach - the stomach releases hydrochloric acid which killed bacteria in food

the skin - the skin acts as a barrier, preventing disease from entering the body

Question 16

what is an STI?

Answer 16

a sexually transmitted infection

Question 17

what are examples of an STI?

Answer 17

HIV, AIDS, HPV, chlamydia, gonorrhea, syphilis, hepatitis etc.

Question 18

what is the most common STI?

Answer 18

chlamydia, which is a bacterial disease
1 in 10 twenty five year olds get it

Question 19

what are the symptoms of chlamydia in men?

Answer 19

• pain when peeing
• 50% of men have no symptoms

Question 20

what are the symptoms of chlamydia in women?

Answer 20

• pain when peeing
• irregular periods
• 80% of women have no symptoms
• can result in infertility in the long term

Question 21

what is the treatment for chlamydia?

Answer 21

antibiotics

Question 22

what is HIV?

Answer 22

human immunodeficiency virus

Question 23

how does HIV effect your body?

Answer 23

HIV attacks white blood cells
l
some people experience flu like symptoms, or none at all
l
usually, there would then be no symptoms for several years
l
during this time HIV can be controlled with antiretroviral drugs, stopping the virus from replicating
l
eventually HIV destroys the white blood cells, turning into AIDS
l
you are then more vulnerable to pathogens that the body would normally fight off and this can lead to death

Question 24

how is HIV spread?

Answer 24

• infected bodily fluids
• sharing needles
• unprotected sex

Question 25

what do antiretroviral drugs do?

Answer 25

the stop the cells from replicating

Question 26

what are preventions of pregnancy (contraceptives)?

Answer 26

- using a condom (a barrier method) - using birth control (hormonal method)

Question 27

what are advantages of hormonal methods of contraceptive?

Answer 27

- it prevents pregnancy - works at all times

Question 28

what are disadvantages of hormonal methods of contraceptive?

Answer 28

- acne - headaches - mood swings - doesn't protect against STI's

Question 29

what time of contraceptive provides protection against STI's?

Answer 29

the only one is a condom

Question 31

what are the stages in developing new medicines?

Answer 31

first is discovery - researchers target a disease and develop ideas for treatments until they find potential treatments next is development - after it's discovered, it is vital that its checked for safety, effectiveness and dosage. it's important to test drugs marketed to pregnant women etc. then, preclinical testing: phase 1: computer modelling and testing in cells phase 2: testing on animals then clinical trials: testing on humans phase 1: test the drugs on a small number of healthy people for safety phase 2: testing people with the illness, at low doses, to check for effectiveness and safety phase 3: continued testing on a large number of people then the medicine is declared safe, doctors will be allowed to use it. clinical trials will still continue as every patient who takes it will be monitored.