Ch 3 Prokaryotic Cells Flashcards

1
Q

Describe the plasma membrane

A

The structure of plasma membranes for the bacterial cells follows the fluid mosaic model. It includes a bilayer that contains mainly phospholipids formed by ester linkages and proteins. The phospholipids also have straight chains. The plasma membranes of archaea can either be a bilayer of phospholipids or a lipid monolayer. The membrane phospholipids are formed with ether linkages and have branched chains.

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2
Q

What is the function of the plasma membrane?

A

Controls which molecules can enter or leave the cell. It is selectively permeable.

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3
Q

How are Archaeal plasma membranes different than both Bacterial and Eukaryotic plasma membranes?

A

Bacterial and eukaryotic plasma membranes contain a phospholipid bilayer formed with ester linkages. The phospholipids in this membrane also contain straight chains in proteins. Contrastingly, archaeal plasma membranes can be either a bilayer of phospholipids or a lipid monolayer. Their phospholipids are formed with ether linkages and unlike bacterial and eukaryotic plasma membranes, they have branched chains.

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4
Q

Describe the cell wall

A

In bacterial cell walls, the major component is called peptidoglycan. In archeal cell walls, the major component is pseudopeptidoglycan.

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5
Q

What is the function of the cell wall?

A

It protects the cell from harsh conditions in the outside environment.

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6
Q

Describe the glycocalyx

A

It is a sugar coat made up of glycoproteins and glycolipids. It is found in a few prokaryotes, and it can either be a capsule layer or slime layer.

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7
Q

What is the function of the glycocalyx?

A

It helps cells adhere to surfaces and assists in forming biofilms.

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8
Q

What is the capsule layer of the glycocalyx?

A

An organized layer outside the cell wall that is made up of proteins or polysaccharides.

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9
Q

What is the slime layer of the glycocalyx?

A

A layer composed of polysaccharides, glycolipids, or glycoproteins that is loosely attached to the cell wall.

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10
Q

What is the S layer?

A

It is a type of structure in the cell envelope that is found outside the cell wall in bacteria. In archaea, this layer is the cell wall. The S layer is made up of a mix of glycoproteins and structural proteins.

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11
Q

What is the function of the S layer?

A

possibly play roles in many functions of various prokaryotic cells. For instance, helping a cell combat osmotic pressure.

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12
Q

What are fimbriae?

A

They are short proteins that project from the cell surface. There are hundreds of them on a cell.

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13
Q

What is the function of fimbriae?

A

These projections allow a cell to attach itself to other cells and surfaces.

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14
Q

What are pili?

A

longer and less numerous than fimbriae
- proteins that also help the attachment of a cell to surfaces.

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15
Q

What are F/conjugation/sex pili?

A

crucial for the transfer of DNA among two bacterial cells

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16
Q

What are flagella?

A

Spiral filaments that are outward extensions of the cell. They are stiff and made up of flagellin protein subunits. They move by spinning in solution.

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17
Q

What is the function of flagella?

A

They help cells move in aqueous environments.

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18
Q

What is monotrichous?

A

A cell with one flagella at one side of the cell.

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19
Q

What is amphitrichous?

A

A cell with one flagellum at each end

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20
Q

What is lophotrichous?

A

A cell that contains multiple flagella at one end.

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21
Q

What is petrichous?

A

A cell that has flagella all around its surface

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22
Q

What is a gram + cell wall?

A

made up of multiple layers of peptidoglycan that have teichoic acids embedded into them and reach beyond them. Some can also produce a waxy mycolic acid layer
- simply structured cell wall

23
Q

What is a gram - cell wall?

A

They have a thinner layer of peptidoglycan. Their inner membrane is a plasma membrane with phospholipids and membrane proteins. The outer membrane of gram-negative cells contains lipopolysaccharide (LPS), porin, and an O antigen.

24
Q

What is simple diffusion?

A

The movement of molecules from areas of higher concentrations to areas of lower concentration. They move along the concentration gradient.

25
Q

What is facilitated diffusion?

A

Channels or carriers aid the movement of large and charged molecules across the membrane.

26
Q

What is osmosis?

A

The diffusion of water

27
Q

What is hypertonic?

A

occurs when the solute concentration outside a cell is higher than inside the cell. When this happens, water responds by moving out of the cell. The cell shrinks

28
Q

What is hypotonic?

A

when the solute concentration inside the cell is higher than the outside of the cell. As a result, water moves into the cell causing it to swell.

29
Q

What is isotonic?

A

when the solute concentrations inside the cell and outside the cell are equal. This results in no net movement of water.

30
Q

What is active transport?

A

Requires ATP/energy to move molecules against the concentration gradient.

31
Q

What is group translocation?

A

A molecule is chemically modified as it moves into the cell against its concentration gradient. They are modified so they do not need transport against a troublesome concentration gradient.

32
Q

What is a cytoplasm?

A

It is made up of dissolved chemicals that are needed for growth and water. It is a gel-like substance that is contained in a plasma membrane.

33
Q

What is the function of the cytoplasm?

A

It suspends and supports the organelles inside the cell.

34
Q

What is the nucleoid?

A

Is found in prokaryotic cells and is a condensed area of DNA. This region is concentrated with prokaryotic DNA and DNA-associated proteins.

35
Q

What is the function of the nucleoid?

A

contains nucleoid associating proteins that are involved in assisting the packaging and organization of the chromosome

36
Q

What type of nucleic acid do prokaryotes use for their genome?nucleotides? How is it packaged in the cell?

A

DNA, they are packaged by the nucleoid-associated proteins found in the nucleoid.

37
Q

What are plasmids?

A

Double stranded DNA molecules that are small, and circular. It is DNA that is not included in the chromosome. These molecules are important to the survival of an organism.

38
Q

What is the function of a plasmid?

A

They carry genes that provide advantageous traits. For instance, antibiotic resistance.

39
Q

What is the ribosome?

A

They are made up of proteins and ribosomal RNA. Prokaryotic ribosomes are located in the cytoplasm and are called 70S ribosomes due to their size. Bacterial and archaeal ribosomes are the same size, but they have different proteins and rRNA molecules. The archaeal ribosomes are also more similar to eukaryotic ribosomes rather than bacterial.

40
Q

What is the function of a ribosome?

A

These organisms are responsible for the synthesis of proteins.

41
Q

What type of ribosomes (e.g. size) do prokaryotes have? What are the sizes of the large and small subunits?

A

70S ribosomes that contain a 50S large subunit and a 30S small subunit.

42
Q

What are inclusions?

A

Structures in the cytoplasm of prokaryotic cells. They are clumps of stored nutrients and certain materials that are found inside the cell.

43
Q

What are the functions of inclusions?

A

The storage place of excess nutrients and materials in a prokaryotic cell.

44
Q

What are some examples of inclusions?

A

Volutin granules
Sulfur granules
Gas vacuoles

45
Q

What are endospores?

A

Structure of bacteria that can survive environmental conditions that could have originally killed the bacteria.

46
Q

What are the functions of endospores?

A

When cells are in a dormant state, they help protect the bacterial genome from harmful environmental conditions.

47
Q

What type of bacteria produce endospores?

A

Those in the genera Bacillus and Clostridium

48
Q

Under what conditions are endospores produced?

A

They are produced when the environmental conditions are unfavorable for bacterial cells in a dormant state.

49
Q

What is a vegetative cell?

A

one that is able to do its metabolic activities and fulfill its normal functions.

50
Q

What are the steps involved in the creation of endospores?

A

1) DNA replicates
2) Membranes form around the DNA
3) Forespore forms additional membranes
4) protective cortex forms around the spore
5) protein coat forms around the cortex
6) spore is released

51
Q

What is periplasm?

A

It is a gel-like matrix that is located in the periplasmic space between the plasma membrane and the peptidoglycan cell wall.

52
Q

What is LPS?

A

Lipid A, a core polysaccharide, and an O side chain In infections involving gram-negative bacteria, lipopolysaccharide works as an endotoxin as it aids to symptoms such as septic shock and fever.

53
Q

What is a acid fast (genus mycobacterium)?

A

Since Myobacteriaceae have a waxy mycolic acid layer on the external surface of their cell walls, they are considered acid-fast bacteria. This signifies that they require acid-fast stains for microscopy. These stains are more effective at penetrating the waxy layer.

54
Q

What are mycoplasmas?

A

They are very small prokaryotic single-celled organisms that lack a cell wall. Due to their lack of a cell wall, they are unaffected by certain antibiotics. Mycoplasmas are often responsible for respiratory infections.