Microorganisms: the Bacteria kingdom

Question 1

Are bacteria…
1. Unicellular or multicellular
2. Prokaryotic or eukaryotic

Answer 1

1. Unicellular
2. Prokaryotic

Question 2

Where are they found?

Answer 2

Everywhere: soil, water, air,soil, on/in other living organisms. They are ubiquitous.
Can be harmful or beneficial

Question 3

MAIN Structure of bacteria

How big are they? Numbers of them?

Answer 3

They are the smallest cellular organisms (0,5 to 5 micrometers) and are the most abundant.

Question 4

MAIN Structure

Describe a prokaryote

Answer 4

simpler cells structure, no nuclear membrane or membrane bound organelles

Question 5

MAIN Structure

List the 5 main components of bacteria and relate each to their functions.

Answer 5

1. A cell wall made of a mixture of proteins and sugars (peptidoglycan). Strong and flexible to protect the cell. gram +: a lot, gram - (a little)
2. A cell membrane below the cell wall to control the exit/entry of substances.
3. The cytoplasm contains granules of glycogen and lipids to store energy for the cell.
4. Ribosomes for making proteins.
5. One double stranded circle of DNA (bacterial circular chromosome) in the cytoplasm. Found in a viscous region called the nucleoid.

Question 6

Structure: other bacteria

Name an anatomical property of other bacteria involved in DNA.

Answer 6

Plasmids: extra small pieces of extrachromosomal DNA. Plasmids contain different DNA to the main bacterial DNA and are important in genetic engineering.

Question 7

Structure: other bacteria

Name a characteristic that surrounds them.

Answer 7

Mucous surround some,
1. preventing them from drying out
2. helps them adhere to each other to form colonies

Question 8

OTHER bacteria

Name a characteristic of bacteria that enables motility.

Answer 8

Flagella (one or more) enable them to move. They can move away from unfavourable stimulus like dryness and favourable stimulus like light or oxygen.

Question 9

OTHER bacteria

Name a bacteria characteristic that enable them to attach to each other.

Answer 9

1-100s protein rods projecting from the surface of the bacteria called pili enable them to attach cells together or to surfaces.

Question 10

What do autotrophic bacteria contain?

Answer 10

Cyanobacteria may contain thylakoids containing chlorophyll and other pigments for photosynthesis.

Question 11

FUNCTIONS

Function of the pillus

Answer 11

• Transfer of plasmids from one bacterium to another (sex pilli in a process called conjugation)
• Attaches cells/bacteria to each other

Question 12

FUNCTIONS

Function of the cell wall

Answer 12

To protect the bacterium

Question 13

Function of the circular DNA

Answer 13

• codes genes for needed proteins
• controls the cell
• contains hereditary information

Question 14

Function of the flagellum

Answer 14

motility

Question 15

function of the cell membrane

Answer 15

selective permeability

Question 16

function of the mucous layer

Answer 16

• protects bacteria from drying out
• allows bacteria to stick together to form colonies

Question 17

function of the ribosome

Answer 17

site of protein synthesis

Question 18

function of the plasmid

Answer 18

• special genes (extrachromosomal DNA)
• Antibiotic resistant genes in them
• ## can have many copies

Question 19

How are bacteria classified?

Answer 19

1. shape
2. amount of peptidoglycan in walls

Question 20

CLASSIFICATION

Differentiate between gram-negative and gram-positive bacteria. What is the function of this testing?

Answer 20

gram +: more peptidoglycan in walls, stain purple (more, darker)
gram - : less peptidoglycan in walls, stain pink

-> to select the appropriate antibiotic depending on the bacteria and to name them.

Question 21

CLASSIFICATION

What shapes and forms can bacteria take?

Answer 21

1. spherical (cocci)
2. rod-shaped (bacilli)
3. spiral (spirilla)
4. comma shaped (vibrios)

They can form chains or clusters

Question 22

What are the three categories of nutrition heterotophic bacterial organisms can have?

Answer 22

saprophytic: breaks down dead organic matter ie.decomposers
mutualistic: benefit another organism
parasitic: can cause disease ie. pathogens

Question 23

Nutrition

explain how autotrophic bacteria produce nutrients

Answer 23

-> make own nutrients
- some use light (photosynthesis)
- some use chemosynthesis (sulphur, hydrogen sulphide gad, methane gas. Some make atmospheric nitrogen available to plants and thus form part of the Nitrogen Cycle. Nitrogen fixing is NOT decomposing.

Question 24

Nutrition

What are most bacteria?

Answer 24

heterotrophic – rely on other organisms for their nutrients.

Question 25

# heterortophic bact. Describe saprophytic bacteria

Answer 25

These bacteria obtain nutrients from dead matter -- decomposers. They are responsible with fungi, for decaying and recycling organic material in the soil.

Question 26

# heterotophic bact. Describe mutualistic bacteria

Answer 26

Live with another organism and get food from it and help it. bacteria living on skin, protecting from pathogens. 100 trillion in gut help get nutrients from waste. bacteria in the gut of horses produce ce;lulase, enabling them to digest cellulose.

Question 27

parasitic

Answer 27

feed on living organisms, often causing disease (pathogenic)

Question 28

Differentiate between parasitic and pathogenic

Answer 28

parasitic: lives in/on another organism and derives nutrients from the host. They don't always cause disease. pathogenic: cause disease

Question 29

# REPRODUCTION In what three ways do bacteria reproduce?

Answer 29

1. Asexually through binary fission if conditions are favourable. 2. Producing endospores (asexual in unfavourable conditions) 3. Sexually (conjugation)

Question 30

# REPRODUCTION Describe the process of binary fission. | Is this mitosis?

Answer 30

1. The nuclear material duplicates 2. The DNA is segregated and a septum forms 3. The cell splits into two, forming two indetical daughter cells. occurs very rapidly: every 20 mins -- 10 000 000 in 15 mins | Not mitosis: similar, but true stages not followed

Question 31

# REPRODUCTION Describe reproduction in unfavourable conditions

Answer 31

1. the original cell metabolism and DNA is replicated 2. cytoplasm membrane pinches making a forespore 3. Vegetative DNA starts to disintegrate as the cytoplasmic membrane engulfs the forespore in a second membrane 4. A cortex of calcium is deposited. 5. the spore coat forms 6. endospore matures and original cell lyses releasing the endospores.

Question 32

# REPRODUCTION Describe conjugation.

Answer 32

1. a bridge is formes between the two bacteria by the sex pili 2. genetic material is exchanged 3. they seperate and divide into two daughter cells each. no true sexual reproduction as there is gamete formation or fusion.

Question 33

# Pathogenic Bacteria

Question 34

# Pathogenic Bacteria Describe bacteria which cause plant disease.

Answer 34

1. Not great in number. 2. Enter hosts through holes, gaps and wounds. 3. Agrobacterium tumefaciens which causes the formation of tumours in over 140 species of plants.

Question 35

# Pathogenic Bacteria What effect do bacteria have on the animal kingdom?

Answer 35

Both effects on the quality of life and mortality.

Question 36

# Pathogenic Bacteria How do bacteria cause disease in humans?

Answer 36

1. Destroy body tissues (eg. Streptococcus which secretes enzymes that digest host cells thereby allowing for further invasion). FLESH EATING BACTERIA 2. By producing toxins, which are made from proteins. EXOtoxins are produced by gram positive bacteria and are secreted into surroundng environment. Eg. Tetanus 3. BY producing toxins, which are made from lipids and carbohydrates. ENDOtoxins are released from the surface of gram-negative bacteria into the host's cells when the bacteria die and cause fevers (body fights using WBCs), body aches and weakness. Eg. Escherichia. Coli

Question 37

# TREATMENT How are bacteria mostly treated and how were they first discovered?

Answer 37

-> antibiotics -> Accidentally discovered in 1929 by Alexander Fleming who noticed death of bacteria aroud a fungus in an old bacteria plate: penicillum notatum.

Question 38

# TREATMENT Why does penicillin not affect human cells but kills bacterial cells?

Answer 38

Target specifical to prokaryotic cells (bacteria) not eukaryotic cells (human).

Question 39

# ANTIBIOTICS In what ways are bacteria becoming more multi-drug resistant?

Answer 39

1. Don't finish taking them: only weakest have been killed, a few are naturally resistant. Then, these continue to grow and reproduce, creating an antibitoic resistant strain, thus not being able to be killed. 2. Overprescription of antibiotics: become more exposed to the antibiotics, more of a chance to become resistant every time. 3. Giving huge amounts to livestock (bacteria on them, surroudnign area resistant).

Question 40

# ANTIBIOTICS Can resistance in bacteria go away over time?

Answer 40

yes, thanks to selective pressure being diminished, energy used.

Question 41

# ANTIBIOTICS How are antibiotics synthesised?

Answer 41

By culturing the bacteria/fungi that secrete them and then filtering the antibiotic out of the culture meidium. Then chemically modified in a laboratory for effectiveness and fewer side effects.

Question 42

# ANTIBIOTICS Explain the effects on humans of drug-resistant bacteria.

Answer 42

1. Spreading globally, threatening our ability to resist infection: pneumonia, gonohrrea and blood poisoning are less effectively treated. 2. Heading for a post-antibiotic era (\common infections can once again kill).

Question 43

# BENEFICIAL BACTERIA Explain the importance of intestinal bacteria.

Answer 43

1. Produces Vit K (without, blood disorders) EG. E coli 2. Probiotics are beneficial bacteria that are gained through food: a. able to resist digestion. by gastric juices as they live in the colon and need to get there alive b. They help us digest our food c. They keep pathogenic bacteria and fungi levels low thanks to competition d. Taking an antibiotic can kill them too, leaving you feeling sick and unable to digest food.

Question 44

# BENEFICIAL BACTERIA Describe Lactobacillus rhamnosus

Answer 44

1. Reduces the risk of diarrhoea amd reduces the time of acute cases. does this by competing with pathogens and by enhancing the immune system's response to intestinal pathogens. 2. Produces the enzyme lactase which reduces lactose intolerance 3. Used to treat rotavirus (diarrhoea)