Transcript CHP 7 - Unit3Biology

UNIT THREE
BIOLOGY
AREA OF STUDY #2: DETECTING &
RESPONDING
EXAM REVISION LECTURE
CHP 7: INFECTION & DISEASE
CHP 7 TOPIC 1: DEFINING DISEASE
The term disease refers to any change that impairs the functioning of an
individual in some way. That is, it harms the individual.
CHP 7 TOPIC 1: DEFINING DISEASE/ TRANSMISSION
Infectious Disease
Chapter 7 - Disease Causing Organisms
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CHP 7 TOPIC 1: DEFINING DISEASE/ TRANSMISSION
Transmission of Disease
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CHP 7 TOPIC 1: DEFINING DISEASE/ TRANSMISSION
Contact Transmission
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CHP 7 TOPIC 1: DEFINING DISEASE/ TRANSMISSION
Vehicle Transmission
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CHP 7 TOPIC 1: DEFINING DISEASE/ TRANSMISSION
Vector Transmission
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Topic CHP 7.1 Questions:
1. Do all pathogens that enter an organism cause disease? Yes / No
2. Do all pathogens that enter an organisms of different species cause the same disease? Yes / No
3. Is a broken arm by definition, a disease? Yes/ No
4. Is cystic fibrosis and infectious disease? Yes/ No
5. What kind of microscope would you need to use to identify the presence of:
– Bacteria:_______________
– Fungus: ________________
– Viriods: ________________
– Protozoan: _____________
6. How does a ‘vector’ differ from a ‘host’? _____________________________________
________________________________________________________________
7. What is the likely method of transmission of infection of the following:
– Prions: _________________
– Influenza: _______________
– E. coli: _________________
/12 Marks
CHP 7 TOPIC 2: SUMMARY OF DISEASE CAUSING ORGANISMS
Organism
or Agent
Structural
Characteristics
Fungi
Unicellular or multicellular
organisms. Consist of
eukaryotic cells. Cell walls
composed of chitin.
(original source of
penicillin)
Yeasts: unicellular fungi.
Cells have nuclei.
Reproduce by budding.
Candida albicans causes thrush
Moulds: multicellular fungi.
Can invade tissue by
hyphae.
Many plant diseases: Dutch Elm
disease; rust diseases; ringworm
(not a worm!), athletes foot.
Unicellular (animal like
protists- ingest food).
Eukaryotes
Amoebas: single celled
organisms which move by
the use of pseudopodia.
Amoebic dysentery – intestinal
infection
Protozoa
Sub Groups
Apicomplexans: spore
forming parasitic protozoa
Worms
Multicellular, eukaryotic,
specialised for the parasitic
way of life. Mouthparts
may be modified to form
hooks; digestive systems a
re simple; generally
produce numerous
offspring
Examples of Diseases
Plasmodium causes malaria
Nematoda worms (round
worm, hookworm, pin
worm)
Trichinosis causes an often fatal
disease in which worms invade
muscle tissue. Elephantiasis –
worms block lymph vessels
(Flatworms) Flukes and
tapeworms
Schistosoma is a parasite of
human blood. Intestinal
tapeworms pain, discomfort and
increased appetite
Organism or
Structural Characteristics
Sub Groups
Examples of Diseases
CHP
7
TOPIC
2:
SUMMARY
OF
DISEASE
CAUSING
ORGANISMS
Agent
Prion
Protein molecule
-
Viroid
A short strand of RNA with
no protein coat
-
Virus
Nucleic acid surrounded by a DNA viruses. They may
protein coat. Some are
contain single or double
enveloped in a modified
stranded DNA molecules
membrane
Bacteria
Prokaryotic cells, they lack
membrane bound
organelles. Contain a single
round chromosome (and
many plasmids)
BSE (mad cows disease),
Creutzfeldt-Jacob disease
Smallpox, cowpox,
herpes, and warts.
Common cause of sore
throats.
RNA Viruses. They are
usually single stranded;
some contain two RNA
strands
Polio hepatitis, influenza
and colds., aids, Ebola,
measles, mumps
Cocci: spherical bacteria
Staphylococcus aureus
causes skin and wound
sores. Streptococcus
causes sore throat
Bacilli: rod shaped bacteria Diphtheria, leprosy,
tuberculosis
Spirilla: spiral shaped
bacteria
Gram Positive/ Gram
Syphilis, lyme disease
Topic CHP 7.2 Questions:
1. Circle which of the following would be classified as living:
HIV
E. coli
a Prion
plasmodium
yeast
2. True/ False: viroids are the smallest known infectious particles
3. List two virus sub groups: _______________ & _________________________
4. Name one protozoan that causes disease in mammals: ____________________
5. True / False: penicilin is affective against bacteria and fungi but not virus’
6. Which of the following are prokaryotic: (circle)
E. coli
E. epidermis
HIV
Plasmodium
Yeast
CHP 7 TOPIC 3: CHARACTERISTICS OF DISEASE CAUSING PRIONS
Prion Diseases
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CHP 7 TOPIC 3: CHARACTERISTICS OF DISEASE CAUSING PRIONS
• prions are unique in that they are both contagious and hereditary
• they are also resistant to sterilization
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Topic CHP 7.3 Questions:
Prions
1. Which of the following is a possible source of prion disease:
a) Infected brains
b) Infected intestines
c) Contaminated water
2. Which of the following is a possible cause of prion disease:
a)
b)
c)
Infection carried by a vector
Infection caused by a parasite
Genetic mutation
3. Prions are infectious proteins. How do they cause disease: _________________________
_________________________________________________________________________
4. True / False: prions can be destroyed or deactivated by heating or cooling
5. True / False: prions have an incubation period up to ten years
6. Name one disease caused by prion infection: _______________________
CHP 7 TOPIC 4: CHARACTERISTICS OF DISEASE CAUSING BACTERIA
Bacteria- Kingdom Monera
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CHP 7 TOPIC 4: CHARACTERISTICS OF DISEASE CAUSING BACTERIA
Gram Stains
•
1984, bacteriologist, Joachim Gram developed the gram stain
•
Gram stain distinguishes between two main groups of bacteria
•
Important stain to help identify which drugs are useful
•
Gram Positive bacteria take up the violet colour of the stain
– Gram + have a cell wall layer of teichoic acid
– Are particularly susceptible to penicillin and sulphonamide
drugs
Gram Negative bacteria fail to take up the stain and by default
stain pink
– Gram – have no teichoic acid in their walls and smaller
amounts of disaccharides and amino acids
– Outer layer of lipid compounds enables these bacteria to
resist penicillin and other drugs
– Also makes phagocytosis of the bacteria very difficult
– Effective drugs include streptomycin, tetracycline
•
– S. empidermis: gram negative (susceptible to penicillin)
– S. ecoli: gram negative (resistant to penicillin)
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Topic CHP 7.4 Questions:
Bacteria
1. Which of the following is a possible source of bacterial disease:
a)
b)
c)
d)
Infected brains
Infected intestines
Contaminated water
All of the above
2. True / False: all bacteria are pathonogenic
3. True / False: all bacteria contain DNA
4. The cell wall of bacteria is made out of:
a)
b)
c)
d)
e)
Chitin
Cellulose
Protein
Nofninidea
Carbohydrates, lipids and amino acids
5. Three basic shapes of bacteria include: __________________, ________________ &
_____________________
6. Most bacteria have a casing around the outside of the cell wall called a : c_________
7. Two organelles (not including cell membrane) present in some bacteria include:
________________, _______________
8. How many chromosomes does each bacterial cell have? 1, 3, more than 3
CHP 7 TOPIC 5: CHARACTERISTICS OF VIRUS’
Viruses
• Viruses are the smallest known reproducing things.
• A virus comprises of DNA or RNA surrounded by one or more coats of
protein.
• The significant feature about viruses is that they cannot reproduce outside a
cell – they need to enter a host cell to reproduce.
• Most viruses are only able to invade one host although some have a host
range
• Are intracellular parasites to animal, plants, fungi, protists and bacteria
BACTERIAPHAGE
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CHP 7 TOPIC 5: CHARACTERISTICS OF VIRUS’
How Do Viruses Affect a Host Cell?
•
Viruses must enter a host cell to reproduce.
•
They use components of the host cell as a source of energy and material to make new viruses
and ultimately destroy the host cell.
•
When a virus infects a cell, its protein coat becomes attached to the cell wall and its DNA is
injected into the cell.
•
The viral DNA ‘takes over’ the cell and uses energy from the mitochondria and material within
the cell to make new viral protein coats and viral DNA.
•
The new parts are then assembled into new viruses and in a matter of hours, hundreds of new
viruses are produced.
Chapter 7 - Disease Causing Organisms
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CHP 7 TOPIC 5: CHARACTERISTICS OF VIRUS’
Viral Pathogens
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CHP 7 TOPIC 5: CHARACTERISTICS OF VIRUS’
The Structure of HIV
True / False
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Topic CHP 7.5 Questions:
Virus
1. Which of the following is a possible source of viral disease:
a)
b)
c)
d)
Infected brains
Infected intestines
Contaminated water
All of the above
2. True / False: all virus’ are pathonogenic
3. True / False: all virus’ contain either DNA or RNA
4. True / False: viruses are obligate intracellular parasites
5. The cell wall/ coat of virus is made out of:
a)
b)
c)
d)
e)
Chitin
Cellulose
Protein
Nofninidea
Carbohydrates, lipids and amino acids
6. Why are viruses hard to attack and destroy? _____________________________________
7. True/. False: Bacteriophages are attacked by viruses
8. What name is given to the protein coat of a virus? a _______________
CHP 7 TOPIC 6: CHARACTERISTICS OF DISEASE CAUSING PROTOZOANS
Protozoans
CHP 7 TOPIC 6: CHARACTERISTICS OF DISEASE CAUSING PROTOZOANS
Malaria
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CHP 7 TOPIC 6: CHARACTERISTICS OF DISEASE CAUSING PROTOZOANS
Malaria
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Topic CHP 7.5 Questions:
Protozoans
1. Which of the following is the most likely source of disease caused protozoans:
a) Cooked meat/ fish
b) Contaminated water
c) Airborn infection
2. True / False: all protozoan’s are pathonogenic
3. True / False: all protozoans contain both DNA & RNA
4. True / False: disease causing protozoans are obligate intracellular parasites
5. True/. False: mosquiotos cause the disease known as malaria
6. True/ False: humans are the primary host for plasmodium
7. What name is given to the protective capsule used by some protozoans to avoid being
destroyed by a host: ______________________________
CHP 7 TOPIC 7: CHARACTERISTICS OF DISEASE CAUSING: OTHER
Fungal& Disease
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CHP 7 TOPIC 7: CHARACTERISTICS OF DISEASE CAUSING: OTHER
Multicellular Parasites
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CHP 7 TOPIC 7: CHARACTERISTICS OF DISEASE CAUSING: OTHER
Insect Parasites
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CHP 7 TOPIC 7: CHARACTERISTICS OF DISEASE CAUSING: OTHER
Parasitic Ticks & Mites
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CHP 7 TOPIC 7: CHARACTERISTICS OF DISEASE CAUSING: OTHER
Parasitic Roundworm
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CHP 7 TOPIC 7: CHARACTERISTICS OF DISEASE CAUSING: OTHER
Parasitic Flatworms
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CHP 7 TOPIC 3: CHARACTERISTICS OF DISEASE CAUSING ORGANISMS
How do Pathogens infect and affect?
1.
Must cause damage to the host (generally one or a combination of the following)
•
Invasion of tissue (the pathogen reproduces in and spreads through body tissue , causing
breakdown of tissue/ cell death): i.e. enzymes of bacteria
•
Production of toxins: exotoxins in bacteria; endotoxins
•
Inhibits normal cell function such as metabolism, growth and repair
•
Consumes nutrients (i.e. parasites)
•
Produces damaging proteins (prions and viruses)
•
Body’s own reactions – fever, inflammation and swelling – necessary but harmful!
CHP 7: CHARACTERISTICS OF DISEASE CAUSING ORGANISMS
Key Terms:
Parasite: organism that lives on or in another organism and feeds from it , usually without killing it.
Endoparasite: parasatistic organism that lives inside the host
Ectoparasite: parasatistic organism that lives/ feeds on the outside of the host
Host: organism or cell that a parasite lives in or on.
Primary Host: in which mature parasite lives its adult stage (final host) before passing on eggs
Intermediate Host: a host necessary for completion of life cycle (not adult form of parasite- site of asexual
reproduction)
Vector: an insect or animal that carries a pathogenic organism from one host to another
Exotoxins: toxins secreted (including bacteria) into the surrounding medium
Endotoxins: toxins produced by an organism and released only when the organism disintegrates
Fungicides: chemicals that kill fungi
Alfa toxin: a toxin produced by fungus that may be responsible for some cancers
Pathogen: organism able to cause disease in a host
CHP 7 TOPIC 7: CHARACTERISTICS OF DISEASE CAUSING: OTHER
Antiseptics and Disinfectants:
• antiseptics are used to kill pathogens on the skin
•Disinfectants are used to kill pathogens on an object
•Both work by interfering with cell structures and functions
Antibiotics and Antimicrobials
• Antibiotics were originally produced naturally by microorganisms, but some can now be made
synthetically. They are active against other microorganisms
• antimicrobial agents are chemicals used to inhibit growth of bacteria. They interfere with
bacterial cell walls, cell membranes and protein and nucleic acid synthesis
•Fungicides and Antifungicides
Hard to develop because of strong similarities in cellular functions between the host and the
pathogen
Antivirals
• Hard to treat viruses without harming host cells
• inhibiting the synthesis of RNA and DNA in retroviruses has been particularly successful
•Interferons are antiviral (natural!)
Antiprotozoan and Anthelminthic Drugs
Very little research in this area
Topic CHP 7.7 Questions:
Prions
1. Which of the following is a possible source of parasitic infection:
a) Cooked food
b) Contaminated water
c) Uncooked fish
2. List two examples of Fungi: __________________ & ________________________
3. The cell wall of fungi is made of:
a)
b)
c)
d)
e)
Chitin
Cellulose
Protein
Nofninidea
Carbohydrates, lipids and amino acids
4. True / False: fungi are autotrophic
5. True / False: fungal infection is called mycosis
6. A parasite that feeds off the outside of its host is called an _______________ parasite
7. Name three adaptations that may be employed by parasites:
1. _____________________________________
2. _____________________________________
3. _____________________________________