Chapter 12 Key Concepts

Question 1

Bacteria can be classified in two way

Answer 1

Basic shape

Cell walls

Question 2

Shapes

Answer 2

Rod bacilli. Chain of bacilli is streptobacilli 
Spherical cocci
Comma shaped vibrios 
Spiralled spirilla 
Corkscrew spirochaetes

Question 3

Two main types of bacterial cell walls

Answer 3

Gram positive bacteria purple blue MRSA

Gram negative bacteria red E. coli

Question 4

Virus

Answer 4

Non living infectious agents
They are Genetic material (DNA or RNA) surrounded by a protein
All naturally occurring ones are pathogenic
The ultimate parasite

Question 5

Why are virus’ so successful?

Answer 5

Reproduce rapidly

Evolve by developing adaptations to their host

Question 6

What are bacteriophages

Answer 6

Virus that attacks baterica

Take over baterial cells and use them to replicate, destroying the bacteria at the same time

Question 7

Use of bacteriophages

Answer 7

Identify and treat some diseases

Question 8

4 examples of a virus

Answer 8

HIV
Herpes sore complex that causes cold sores
TMV that incfects tobacco plants
Bacteriophages

Question 9

Protista

Answer 9

Eurkaryotes

Small percentage are pathogens. They are parasitic so use people or animals as their host organism

Question 10

Two modes of parasitic pathogen Protista action

Answer 10

Use of vector v
Eg malaria and sleeping sickness

Enter directly into the body through polluted water
Eg amoebic dysentery and Giardia

Question 11

Fungi

Answer 11

Eukaryotes
Often multicellular
Many are Saprophytes so digest dead and decaying matter extracellularly before absorbing nutrients

Others are parasitic living on P&a causing the communicable dieases

Question 12

Adaptations of the fungi that makes them so successful

Answer 12

When they produce they make millions of spores that can spread vast distances so spread rapidly and widely through crop plants

Question 13

Pathogens that damage host tissue directly

Answer 13

Virus
Some Protista
Fungi

Question 14

Paths that make toxins that damage host tissue

Answer 14

Most bacteria

Some fungi make toxins that affect host cells and cause disease

Question 15

Virus mode of action

Answer 15

Attach to host cell
Insert their nucleic acid into the host DNA and the nucleic acid is replicated
Viral proteins are synthesised and assembled
Host cell lysis destroying it when new virus’ burst out and then spread to infect other cells

Question 16

How are symptoms caused?

Answer 16

The damage to the tissue plus the way the body responds

Question 17

Mode of action of the Protista

Answer 17

They take over cells and cause them to lysis when new Protista burst out

Don’t take over cell metabolism. Rather they digest and use cell content to reproduce. Eg plasmodium of malaria

Question 18

Mode of action of the fungi

Answer 18

Digest living cells and destroy them

Question 19

Mode of action of the bacteria

Answer 19

Make toxins or poison that damage the host cells in some way causing disease
Some damage by:
Breaking down csm
Damage or inactive enzymes
Interfere with host cells genetic information so cells can’t divide