Lecture 2- Structures of prokaryote

Question 1

what are proteins made of?

Answer 1

polypeptides

Question 2

what are polypeptides?

Answer 2

a long polymer of amino acids joined by peptide bonds

Question 3

what are the functions of proteins?

Answer 3

enzymes
transport proteins
structural proteins

Question 4

what is the function of enzymes?

Answer 4

catalyze chemical reactions

Question 5

what is the function of transport proteins?

Answer 5

move other molecules across membranes into a cell

Question 6

what is the function of structural proteins?

Answer 6

help determine shape of the cell
involved in cell diffusion

Question 7

what is the cytoplasm of the prokaryote?

Answer 7

material bounded by plasma/ cytoplasmic membrane

Question 8

what is the nucleoid?

Answer 8

region that contains the genome (DNA)

Question 9

what is a typical genome?

Answer 9

single circular double stranded DNA, may have 1 or more plasmids

Question 10

what is a plasmid?

Answer 10

smaller circular double stranded DNA
self replicating and carry non essential genes (selective advantage. ex. genes for antibiotic resistance)

Question 11

what does DNA do?

Answer 11

carries genetic information of all living cells.
polymer of deoxyribonucleotides

Question 12

what is the protoplast?

Answer 12

plasma membrane and everything within [macromolecules (amino acids, nucleotides…), soluble proteins, DNA + RNA (nucleoid)

Question 13

function of ribosomes?

Answer 13

site of protein synthesis

Question 14

what does a 70S ribosome have in it?

Answer 14

30S subunit
50S subunit

Question 15

what is the 30S subunit? what is it made of?

Answer 15

small subunit
made of protein and 16S rRNA

Question 16

what is the 50S subunit? what is it made of?

Answer 16

large subunit
made of protein and 23S rRNA and 5S rRNA

Question 17

where are ribosomes in the cell?

Answer 17

cytoplasm (can be plasma associated ribosomes but only when they are to be exported from protein synthesis)
rough endoplasmic reticulum

Question 18

what are 3 cell surface structures?

Answer 18

capsules and slime layers
fimbriae
pili

Question 19

what are capsules and slime layers made of? what is the structure of it?

Answer 19

protein layers/ polysaccharides
can be thick or thin, rigid or flexible

Question 20

what is the function of capsules and slime layers?

Answer 20

assist in attachment to surfaces, protect against phagocytosis and resist desiccation

Question 21

what is fimbriae made of? what type of structures are they?

Answer 21

filamentous protein structures

Question 22

what is the function of fimbriae?

Answer 22

enable organisms to stick to surfaces or form pellicles

Question 23

what is longer, fimbriae or pili?

Answer 23

pili

Question 24

what is pili made of? what type of structures are they?

Answer 24

filamentous protein structures

Question 25

how do pili reproduce?

Answer 25

self replicating

Question 26

what is the function of pili?

Answer 26

assist in surface attachment facilitate genetic exchange between cells (conjunction)

Question 27

what is type IV pili involved in?

Answer 27

twitching motility (how they move)

Question 28

what are cell inclusion bodies?

Answer 28

visible aggregates in cytoplasm

Question 29

what are 3 aggregates?

Answer 29

carbon storage polymers inorganic inclusions magnetosomes

Question 30

what are two examples of carbon storage polymers?

Answer 30

poly- B- hydroxybutyrate (PHB) glycogen granules (polymer of glucose)

Question 31

what is the function of PHB?

Answer 31

lipid storage

Question 32

what are two examples of inorganic inclusions?

Answer 32

polyphosphate granules (volutin) sulfur globules

Question 33

what is the function of polyphosphate granules?

Answer 33

storage of phosphate and energy

Question 34

what is the function of sulfur globules?

Answer 34

storage of sulfur used in energy generation

Question 35

what are magnetosomes?

Answer 35

magnetic inclusions

Question 36

what granules do magnetosomes have inside them?

Answer 36

iron sulfide

Question 37

what does magnetosomes having magnetic properties do?

Answer 37

allows it to orient itself in a magnetic field called magnetotaxis (bacteria migrate along earths magnetic field)

Question 38

where are gas vesicles found?

Answer 38

cytoplasm of prokaryotes

Question 39

how are gas vesicles shaped?

Answer 39

spindle- shaped hollow tubed gas filled structures made of protein

Question 40

are gas vesicles permeable to water?

Answer 40

no, they are impermeable to water, therefore, dont allow water to pass through them

Question 41

what is the function of gas vesicles?

Answer 41

decreasing cell density confer buoyancy in planktonic cells

Question 42

what are endospores highly differentiated?

Answer 42

resistant to heat, harsh chemicals and radiation

Question 43

how do endospores disperse?

Answer 43

wind water animal gut

Question 44

what are endospores produced from?

Answer 44

only by some gram positives

Question 45

what are two examples of endospores?

Answer 45

bacillus clostridium both are anaerobic gram positive rods

Question 46

what is a vegetative cell?

Answer 46

capable of normal growth (metabolically active)

Question 47

what is the process of an endospore going through germination?

Answer 47

vegetative cell (metabolically active) endospore develops in a vegetative mother cell (metabolically inactive) takes 8-10 hours in there mature spore gets released (releases due to lack of nutrients)

Question 48

what are two protective features of the endospore?

Answer 48

layers core

Question 49

what do layers of the endospore protect against?

Answer 49

chemicals enzymes physical damage heat

Question 50

how many membranes do endospores have?

Answer 50

two membranes (permeability barriers against chemicals)

Question 51

what does the core protect against?

Answer 51

heat (because they're dehydrated) Ca-dipicolinic acid small acid soluble proteins DNA damage

Question 52

what are 5 things endospores can resist?

Answer 52

boiling for hours UV and radiation chemical disinfectants desiccation age

Question 53

what is the lifecycle of a spore forming bacterium

Answer 53

stage 1: asymmetric cell division (DNA replicates, identical chromosomes pulled to opposite ends of the cell) stage 2: septation (divides cell into two unequal compartments; forespore (prespore) and mother cell) stage 3: mother cell engulfs the forespore (forespore surrounded by two membranes) stage 4: formation of the cortex (thick layers of peptidoglycan form between the two membranes) stage 5: coat synthesis (protein layers surround the core wall --> spore coat, exosporium) Ca+ and SASP accumulates in the core to stabilize DNA stage 6: endospore matures (core is dehydrated to make it more heat stable) stage 7 mother cell is lysed (mother cell disintegrates, mature spore is released)