Bacterial Cell Structure

Question 1

Phospholipids are composed of

Answer 1

A polar head (glycerol and phosphate group)
2 fatty acid tails (Non-polar)

Question 2

The purpose of phospholipids

Answer 2

Make up the lipid bilayer which is the major lipid component of the membrane

Question 3

Hapanoids

Answer 3

Maintains membrane homeoviscosity in bacteria

Question 4

Facilitated diffusion

Answer 4

Spontaneous passive transport pf molecules or ions across a membrane with specific integral proteins

Question 5

Active transport

Answer 5

Movement of ions or molecules across a cell membrane into a region of higher concentration with the assistance of enzymes requiring energy

Question 6

Respiration (Electron Transport System): proton gradients

Answer 6

The energy-released pumps released pumps hydrogen out of matrix space. The gradient created by this drives hydrogen back through the membrane, through ATP synthase. As this happens, the enzymatic activity of ATP synthase synthesizes ATP from ADP

Question 7

Photosynthesis

Answer 7

Light goes through the ETC to split water as a source of electrons to produce oxygen

Question 8

Ion gradients as driving force for co-transport

Answer 8

When driving ions and molecules pair up and move in the same direction

Question 9

Environmental sensing and signal transduction

Answer 9

The process by which a cell responds to substances molecule move in outside the cell through signaling molecules found in the surface and inside the cell

Question 10

Cytoplasm

Answer 10

Water, Macromolecules (proteins, DNA, RNA), Molecular building blocks and metabolites (AA, nuclei acids, sugars), Inorganic ions (K+,Na+, Cl-)

Question 11

Nucleoid

Answer 11

Biggest structure in a cell and holds all the genetic information in a bacterial cell

Question 12

How do cations (Mg^2+, K+, Na+) help tightly pack DNA?

Answer 12

They associate with the phosphate groups to neutralize the charge

Question 13

How do small positive charged proteins help to tightly pack DNA?

Answer 13

They act as scaffolding for the bacteria to wrap around which also neutralizes the charge

Question 14

How do topoisomerases help tightly pack DNA?

Answer 14

They preform supercoiling

Question 15

Is the nucleoid an organell?

Answer 15

Not membrane-bound so no

Question 16

Polyhydroxybutyrate

Answer 16

Used for carbon storage

Question 17

Cyanophycin

Answer 17

Used for nitrogen storage

Question 18

Volutin

Answer 18

Used for phosphorus storage

Question 19

Where are sulfur globules observed?

Answer 19

Thiomargarita namibiensis

Question 20

What do sulfur globules consist of?

Answer 20

Elemental sulfur

Question 21

Gas vesicles

Answer 21

Provide buoyancy to the cells allowing the cells to regulate their position in a water column in response to light or nutrient levels

Question 22

Carboxysomes

Answer 22

Contains RuBisCO which is involved in the conversion of inorganic carbon into organic matter during photosynthesis

Question 23

O2 competes with CO2 for RuBisCO

Answer 23

Ensures an oxygen-free environment for carbon fixation

Question 24

O2 fixation produces 2-phosphoglycolate

Answer 24

Inhibits some of the other enzymes involved in photosynthesis: accumulation is toxic

Question 25

Is Carboxysome protein encased?

Answer 25

Yes they are likely a precursor to the organelles in eukaryotes

Question 26

Are magnetosomes organelles?

Answer 26

Yes which is rare in bacterial cells

Question 27

What do magnetosomes do?

Answer 27

Cause cells to align with magnetic fields and is believed to allow these bacteria to navigate with respect to Earth’s magnetic field

Question 28

Bacterial cell wall

Answer 28

Protects bacterial cell from changes in osmotic pressure and mechanical/sheer forces and give bacterial their shape

Question 29

What is the structure of the bacterial cell wall?

Answer 29

A NAM (N-Acetylmuramic acid) and a NAG (N-Acetylglucosamine) bonded wth an peptide chain attached to the NAM subunit

Question 30

What is a Monodermic cell?

Answer 30

A one-cell membrane with a thick peptidoglycan external layer to cell membrane

Question 31

What color does a Monodermic cell stain in gram staining?

Answer 31

Purple/violet because it is gram-positive

Question 32

What are some distinguishing characteristics of monodermic cells?

Answer 32

teichoic acid and lipoteichoic acid (adds strength and rigidity to the cell wall)

Question 33

What is a Didermic cell?

Answer 33

two cell membranes (inner and outer) with a thin peptidoglycan layer positioned in the periplasmic space (between the two membranes)

Question 34

What color are Didermic cells when they are gram stained?

Answer 34

Pink because they are gram-negative

Question 35

What distinguishing characteristics are there for Didermic cells?

Answer 35

Lipopolysaccharides on the outer layer of the outer membrane

Question 36

Why do Didermic cells have two phospholipid bilayers?

Answer 36

Shields peptidoglycan from hist immune system and from lysozyme

Question 37

Filament

Answer 37

Extends outward from the cell in a helical structure

Question 38

What is the purpose of the filament in the Flagella

Answer 38

Acts like a screw propeller

Question 39

Hook

Answer 39

A curved adaptor that is comprised of FlgE

Question 40

What is the purpose of a hook on a flagellum?

Answer 40

Forms the transition from the basal body to the filament

Question 41

Basal body

Answer 41

Constructed as a series of disks stacked on top of eachother

Question 42

What is the purpose of the basal body in the flagellum?

Answer 42

Anchors the flagella in the cell envelope and interfaces with the motor that drives rotation

Question 43

Motor

Answer 43

in the plasma membrane and looks like a thread spool for the bottom

Question 44

What is the purpose of the motor in the flagellum?

Answer 44

Converts energy from the proton motive force to drive rotation of the filaments

Question 45

Monotrichous

Answer 45

Single flagella at one end

Question 46

trichous

Answer 46

hair

Question 47

Lophotrichous

Answer 47

Multiple flagella located at one or both ends

Question 48

lopho

Answer 48

tuft/crested

Question 49

Peritrichous

Answer 49

multiple flagella spread all over the surface of the cell

Question 50

Internal flagella

Answer 50

keep the flagellar filament shielded inside the periplasm (spirochetes)

Question 51

Bacterial specialized external structure

Answer 51

Pilus/fimbria

Question 52

Composition of Pilus/fimbria

Answer 52

Pilin protein subunits

Question 53

What is the primary role of pilus/fimbriae?

Answer 53

Adhesion

Question 54

What is the secondary role of pilus/fimbria?

Answer 54

Movement: twitching motility and conjugation

Question 55

What are capsules composed of?

Answer 55

Polysaccharides

Question 56

What are the roles of capsules?

Answer 56

A shield from the immune system
Retain water to prevent desiccation
Adherence to surfaces: Biofilms

Question 57

What are surface arrays (S layers)?

Answer 57

A regular, crystalline-like layer of protein that serves as a suit of armor

Question 58

Where are S-layers found?

Answer 58

Many bacteria (both G+, G- and archeons)

Question 59

What do S-layers protect the cell from?

Answer 59

Infection by bacteriophages
Blocking penetration by predatory bacteria
Shielding the cell from attack by a host’s immune system

Question 60

What are S-layers made of?

Answer 60

acidic and hydrophobic amino acids (some covalently attached to sugars)

Question 61

Where are S-layers located?

Answer 61

Anchored to the outer layer of a cell (peptidoglycan in G+, lipopolysaccharides in G-, plasma membrane in acheons that lack a rigid cell wall)