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Biochemistry > Microbiology > Flashcards

Microbiology Flashcards

1
Q

What are the 2 themes in microbiology?

A
  1. Understanding basic life processes

•Microbes are excellent models for understanding cellular processes in unicellular and multicellular organisms

  1. Applying that knowledge to the benefit of humans

•Microbes play important roles in medicine, agriculture, and industry

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2
Q

What is the importance of microorganisms?

A
  • Oldest form of life
  • Largest mass of living material on Earth
  • Carry out major processes for biogeochemical cycles
  • Can live in places unsuitable for other organisms
  • Other life forms require microbes to survive
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3
Q

What is a cell?

A

A dynamic entity that forms the fundamental unit of life

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4
Q

Name the 4 elements of a microbial structure

A

•Cytoplasmic (cell) membrane
Barrier that separates the inside of the cell from the outside environment

•Cytoplasm
Aqueous mixture of macromolecules, ions, and ribosome

•Ribosomes
Protein-synthesizing structures

Cell wall
Present in most microbes; confers structural strength

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5
Q

Name a few differences between Eukaryotes and Prokaryotes

A

•Prokaryotes

  • No membrane-enclosed organelles, no nucleus
  • Generally smaller than eukaryotic cells

•Eukaryotes

  • DNA enclosed in a membrane-bound nucleus
  • Cells are generally larger and more complex
  • Contain organelles
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6
Q

Define genome and describe DNA in Eukaryotes

A

•Genome

•A cell’s full complement of genes

•Eukaryotic DNA is linear and found within the nucleus

  • Associated with proteins that help in folding of the DNA
  • Usually more than one chromosome
  • Typically two copies of each chromosome
  • During cell division, nucleus divides by mitosis
  • During sexual reproduction, the genome is halved by meiosis
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7
Q

Describe the DNA of prokaryotes

A
  • Prokaryotic cells generally have a single, circular DNA molecule called a chromosome
  • DNA aggregates to form the nucleoid region (Figure 1.2a)
  • Prokaryotes also may have small amounts of extrachromosomal DNA called plasmids that confer special properties (e.g., antibiotic resistance)
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8
Q

What is the difference between a Escherichia coli genome and a human cell?

A
  • Escherichia coli genome
  • 4.64 million base pairs
  • 4,300 genes
  • Human cell
  • 1,000✕ more DNA per cell than E. coli
  • 7✕ more genes than E. coli
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9
Q

What are the 6 characteristics of living cells?

A
  • Metabolism: chemical transformation of nutrients
  • Reproduction: generation of two cells from one
  • Differentiation: synthesis of new substances or structures that modify the cell (only in some microbes)
  • Communication: generation of, and response to, chemical signals (only in some microbes)
  • Movement: via self-propulsion, many forms in microbes
  • Evolution: genetic changes in cells that are transferred to offspring
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10
Q

What drives evolution?

Name some things that ALL cell have and SOME cells have

A
  1. Variation

2.

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11
Q

How do cells carry out chemical reactions?

A

•Enzymes: protein catalysts of the cell that accelerate chemical reactions

  • Cells store and process information that is eventually passed on to offspring during reproduction through DNA (deoxyribonucleic acid) and evolution
  • Transcription: DNA produces RNA

•Translation: RNA makes protein

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12
Q

What can cell growth be defined as? (Think of the big picture)

A

•The link between cells as machines and cells as coding devices

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13
Q

What were the first cells? (Trick Question)

A
  • First self-replicating entities may not have been cells
  • Last universal common ancestor (LUCA): common ancestral cell from which all cells descended
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14
Q

How old is the Earth?

When did the first cells come about?

How long was the world anoxic?

When was the world microbial?

A

Earth is 4.6 billion years old

•First cells appeared between 3.8 and 3.9 billion years ago

•The atmosphere was anoxic until ~2 billion years ago

  • Metabolisms were exclusively anaerobic until evolution of oxygen-producing phototrophs
  • Life was exclusively microbial until ~1 billion years ago
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15
Q

What are the similarities between Archaea and Prokaryotes?

A

Achaea are a prokaryote. The have similarity in structures and functions.

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16
Q

What are the differences between Evolution and a Phylogeny?

A

•Evolution

•The process of change over time that results in new varieties and species of organisms

•Phylogeny

  • Evolutionary relationships between organisms
  • Relationships can be deduced by comparing genetic information in the different specimens (Figure 1.6a)
  • Ribosomal RNA (rRNA) is excellent for determining phylogeny
  • Relationships visualized on a phylogenetic tree
17
Q

What are the three distinct lineages of cells called domains?

Are Archaea and Bacteria related?

A
  • Bacteria (prokaryotic)
  • Archaea (prokaryotic)

Eukarya (eukaryotic

NO not related

18
Q

What 2 domains did LUCA introduce?

What 2 domains did Archaea form?

A

•From the last universal common ancestor (LUCA), evolution proceeded to form two domains

  • Bacteria
  • Archaea

•Archaea later diverged to form two domains

  • Archaea
  • Eukarya
19
Q

Define the following: microbial communities, habitat, ecosystem, microbial ecology

A
  • Microorganisms exist in nature in populations of interacting assemblages called microbial communities (Figure 1.7)
  • The environment in which a microbial population lives is its habitat
  • Ecosystem refers to all living organisms plus physical and chemical constituents of their environment
  • Microbial ecology is the study of microbes in their natural environment
20
Q

How is diversity and abundances of microbes are controlled?

A
  • Diversity and abundances of microbes are controlled by resources (nutrients) and environmental conditions (e.g., temp, pH, O2)
  • The activities of microbial communities can affect the chemical and physical properties of their habitats
21
Q

What environments are microbes found?

A
  • Microbes are found in almost every environment imaginable
  • Extremophiles are Bacteria and Archaea that can grow in extremely harsh environments
  • Very hot or very cold
  • Very acidic or very caustic
  • Very salty or very osmotically stressing
  • Very high pressure
22
Q

Where are microbial cells found?

A
  • Global estimate is 5 ✕ 1030 cells
  • Most microbial cells are found in oceanic and terrestrial subsurfaces
  • Microbial biomass is significant, and cells are key reservoirs of essential nutrients (e.g., C, P, N)
23
Q

What sickness is caused my microbial organisms?

A

Pnemonia

24
Q

What are the positive and negaive impacts of using microbials in Agriculture?

A

•Positive impacts

  • Nitrogen-fixing bacteria
  • Cellulose-degrading microbes in the rumen
  • Regeneration of nutrients in soil and water

•Negative impacts

•Diseases in plants and animals

25
Q

What do Rhigobium bacteria require?

What is Lehemoglobin?

A

Rhigobium bacteria require nitrogen and anaerobic conditions.

Oxygen scavengers.

26
Q

In the body where are there high numbers of microorganisms?

A
  • Colon and oral cavity
  • Positive impacts
  • Synthesize vitamins and other nutrients
  • Compete with pathogens for space and resources
27
Q

How is the intestinal tract selective?

A

The intestinal tract has variable pH’s

28
Q

What are the positive and negative impacts of having micribials in food?

A
  • Microorganisms and food
  • Negative impacts
  • Microorganisms can cause food spoilage; for many foods, methods of preservation are needed
  • Positive impacts (Figure 1.11)
  • Microbial transformations (typically fermentations) yield
  • Dairy products (e.g., cheeses, yogurt, buttermilk)
  • Other food products (e.g., sauerkraut, pickles, leavened breads, beer)

Biochemistry (8 decks)

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