chapter 7 defense

Question 1

pathogen

Answer 1

disease causing organism.

Question 2

Infectious disease

Answer 2

transmissible disease, spread from one person to another.

Question 3

What are the most common pathogens?

Answer 3

bacteria and viruses

Question 4

Other than bacteria and viruses, what other types of pathogens are there?

Answer 4

fungi and animal parasites

Question 5

Prokaryote

Answer 5

Unicellular organism with simple internal structure i.e. no nucleus.

Question 6

Where is DNA found in prokaryotes?

Answer 6

free in the cytoplasm or in PLASMIDS.

Question 7

Do bacteria have a cell wall?

Do bacteria have a cell membrane?

Answer 7

Yes

Yes.

Question 8

Flagella

Answer 8

thin, whip-like structure to help the cell move.

Question 9

Why does the cytoplasm of a bacteria look granular?

Answer 9

Due to ribosomes.

Question 10

Do bacteria have membranes around organelles like mitochondria or golgi apparatus?

Answer 10

no. They are prokaryotes.

Question 11

Give two uses for bacteria

Answer 11

cheese making, yoghurt and sauerkraut.

Question 12

Where are bacteria found on an average human body?

Answer 12

skin, alimentary canal, armpit,

Question 13

Are all bacteria harmful?

Answer 13

No, many are useful i.e. aid digestion.

Question 14

How are pathogens transmitted? (3)

Answer 14

1. direct and indirect contact
2. disease specific vectors
3. contaminated food and water.

Question 15

The body’s external defence mechanisms against pathogens include features of: (6)

Answer 15

1. skin
2. digestive tract
3. urogenital tract
4. respiratory system
5. the ear
6. the eye.

Question 16

When pathogens enter the body, the non-specific immune responses are:

Answer 16

inflammation and fever.

Question 17

What scale is used to measure the size of a bacteria?

Answer 17

microns, micrometres.

Ave diameter is 0.5 to 2 microns.

Question 18

How can bacteria be studied?

Answer 18

on an agar plate.

Question 19

Virus

Answer 19

An infectious agent (very small - nanometers) consisting of a protein sheath surrounding a core of nucleic acid.
They rely on living things for reproduction.

Question 20

Name two scientists that discovered viruses.

Answer 20

Koch Pasteur

Question 21

Can viruses be seen with a light microscope?

Answer 21

No - they are only measured in nanometres.

Question 22

How are viruses studied?

Answer 22

With an electron microscope.

Question 23

Name the two types of nucleic acids that a virus may contain.
Can they contain both?

Answer 23

DNA or RNA

NO.

Question 24

DNA

Answer 24

deoxyribonucleic acid

Question 25

RNA

Answer 25

ribonucleic acid

Question 26

What chemical surrounds the nucleic acid in a virus?

Answer 26

A protein. | (some have a lipid /fat sheath.

Question 27

Why are viruses not considered living things?

Answer 27

They cannot reproduce.

Question 28

What happens when the newly made viruses leave the cell?

Answer 28

The host cell becomes damaged, changed or die.

Question 29

Bacteriophages

Answer 29

Viruses that infect bacteria and kill them

Question 30

Vector

Answer 30

intermediate hosts | e.g. flies or mosquitoes.

Question 31

What vector was used in the bubonic plague?

Answer 31

fleas, rats.

Question 32

What are the two types of transmission of contact?

Answer 32

direct - touch infected person | indirect- touch object previously touched by infected person

Question 33

Give an example of an infection that is caused by ingestion of food/water.

Answer 33

dysentry typhoid fever salmonella

Question 34

List some body fluids that may cause infection if exchanged

Answer 34

blood, saliva, semen, vaginal secretions

Question 35

HIV

Answer 35

human immunodeficiency virus

Question 36

List 3 diseases that are spread by bodily fluids

Answer 36

HIV Hepatitis B and C.

Question 37

How are droplets spread? (4)

Answer 37

coughing, sneezing, talking, breathing

Question 38

List 4 diseases that are spread by droplets

Answer 38

Ebola, mumps, covid, colds and influenza.

Question 39

If a droplet dries out, are the viruses/bacteria killed?

Answer 39

Not always - many can stay VIABLE for a long time. | Chicken pox and measles are spread this way

Question 40

Vectors (animals) can host a pathogen. Give an example of this.

Answer 40

mosquito - malaria, dengue fever flies , ticks, mites. rabies - bats, dogs African sleeping sickness - tsetse fly.

Question 41

Non specific defences

Answer 41

acts against all pathogens

Question 42

specific defences

Answer 42

acts against a particular pathogen

Question 43

List 7 external defences

Answer 43

``` skin mucous membranes hairs, cilia acid cerumen ```

Question 44

What stops the skin from being a good barrier?

Answer 44

cuts and wounds

Question 45

What openings need special/alternative methods of protection in the skin?

Answer 45

mouth, eyes, vagina, anus.

Question 46

Why does the skin have its own bacteria?

Answer 46

Prevents pathogens from finding space to grow.

Question 47

How does sebum help control pathogens?

Answer 47

It contains oils and fatty acids that kill pathogenic bacteria?

Question 48

How does sweat help control pathogens?

Answer 48

It contains salts and fatty acids that prevent the growth of pathogens

Question 49

Where do you find mucous membranes?

Answer 49

They line the body cavities that open to the exterior.

Question 50

Mucous

Answer 50

A sticky fluid that traps pathogens and help stop them from entering the organism.

Question 51

Where are mucous membranes found?

Answer 51

nasal cavities, digestive, urinary tract, reproductive system.

Question 52

Where are hairs found that help tract pathogens

Answer 52

ears, nasal passages.

Question 53

What percentage of pathogens are trapped by hair and mucous in the nose?

Answer 53

90%

Question 54

Cilia

Answer 54

tiny, hair-like projections found on cells. Found in nose and trachea. May be coughed up.

Question 55

Where are acids used for protection in the body?

Answer 55

stomach, vagina, urine, sweat.