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Biology 🫀🩸🧬 🩺 > Microorganisms: the Bacteria kingdom > Flashcards

Microorganisms: the Bacteria kingdom Flashcards

Link TO: DNA AND VIRUSES. NOMENCLATURE FOR SPECIES!!!!!

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1
Q

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

A
  1. Unicellular
  2. Prokaryotic
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2
Q

Where are they found?

A

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

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3
Q

MAIN Structure of bacteria

How big are they? Numbers of them?

A

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

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4
Q

MAIN Structure

Describe a prokaryote

A

simpler cells structure, no nuclear membrane or membrane bound organelles

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5
Q

MAIN Structure

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

A
  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.
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6
Q

Structure: other bacteria

Name an anatomical property of other bacteria involved in DNA.

A

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

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7
Q

Structure: other bacteria

Name a characteristic that surrounds them.

A

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

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8
Q

OTHER bacteria

Name a characteristic of bacteria that enables motility.

A

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

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9
Q

OTHER bacteria

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

A

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

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10
Q

What do autotrophic bacteria contain?

A

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

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11
Q

FUNCTIONS

Function of the pillus

A
  • Transfer of plasmids from one bacterium to another (sex pilli in a process called conjugation)
  • Attaches cells/bacteria to each other
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12
Q

FUNCTIONS

Function of the cell wall

A

To protect the bacterium

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13
Q

Function of the circular DNA

A
  • codes genes for needed proteins
  • controls the cell
  • contains hereditary information
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14
Q

Function of the flagellum

A

motility

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15
Q

function of the cell membrane

A

selective permeability

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16
Q

function of the mucous layer

A
  • protects bacteria from drying out
  • allows bacteria to stick together to form colonies
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17
Q

function of the ribosome

A

site of protein synthesis

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18
Q

function of the plasmid

A
  • special genes (extrachromosomal DNA)
  • Antibiotic resistant genes in them
  • ## can have many copies
19
Q

How are bacteria classified?

A
  1. shape
  2. amount of peptidoglycan in walls
20
Q

CLASSIFICATION

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

A

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.

21
Q

CLASSIFICATION

What shapes and forms can bacteria take?

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

They can form chains or clusters

22
Q

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

A

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

23
Q

Nutrition

explain how autotrophic bacteria produce nutrients

A

-> 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.

24
Q

Nutrition

What are most bacteria?

A

heterotrophic – rely on other organisms for their nutrients.

25
Q

heterortophic bact.

Describe saprophytic bacteria

A

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

26
Q

heterotophic bact.

Describe mutualistic bacteria

A

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.

27
Q

parasitic

A

feed on living organisms, often causing disease (pathogenic)

28
Q

Differentiate between parasitic and pathogenic

A

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

29
Q

REPRODUCTION

In what three ways do bacteria reproduce?

A
  1. Asexually through binary fission if conditions are favourable.
  2. Producing endospores (asexual in unfavourable conditions)
  3. Sexually (conjugation)
30
Q

REPRODUCTION

Describe the process of binary fission.

Is this mitosis?

A
  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

31
Q

REPRODUCTION

Describe reproduction in unfavourable conditions

A
  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.
32
Q

REPRODUCTION

Describe conjugation.

A
  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.

33
Q

Pathogenic Bacteria

A
34
Q

Pathogenic Bacteria

Describe bacteria which cause plant disease.

A
  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.
35
Q

Pathogenic Bacteria

What effect do bacteria have on the animal kingdom?

A

Both effects on the quality of life and mortality.

36
Q

Pathogenic Bacteria

How do bacteria cause disease in humans?

A
  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
37
Q

TREATMENT

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

A

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

38
Q

TREATMENT

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

A

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

39
Q

ANTIBIOTICS

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

A
  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).
40
Q

ANTIBIOTICS

Can resistance in bacteria go away over time?

A

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

41
Q

ANTIBIOTICS

How are antibiotics synthesised?

A

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.

42
Q

ANTIBIOTICS

Explain the effects on humans of drug-resistant bacteria.

A
  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).
43
Q

BENEFICIAL BACTERIA

Explain the importance of intestinal bacteria.

A
  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.

44
Q

BENEFICIAL BACTERIA

Describe Lactobacillus rhamnosus

A
  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)

Biology 🫀🩸🧬 🩺 (5 decks)

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