saccharomyces

Question 1

what is saccharomyces cervisiae?

Answer 1

a species of budding yeast

Question 2

how many chromosomes does S. Cerevisiae have?

Answer 2

16, relatively big genome

Question 3

what does S. cerevisiae do?

Answer 3

utilize carbohydrates producing ethanol and other by-products

Question 4

what are the cell cycle characteristics of S. cerevisiae?

Answer 4

produces both haploid and diploid cells

Question 5

what phase do S. cerevisiae haploid and diploids go under when there aren’t enough nutrients?

Answer 5

stationary phase

Question 6

how are stationary phase cells distinct from non-stationary?

Answer 6

round, bright, and contain much higher levels of storage carbohydrates than proliferating cells

Question 7

what are the two mating types of haploid cells in S. cervisiae?

Answer 7

a or alpha
mating type a produce a pheromone ‘a factor’
mating type alpha produce a pheromone ‘alpha factor’

Question 8

what is a shmoo?

Answer 8

the result of S. cervisiae haploid cells growing towards each other in the G1 phase, soon forming a diploid

Question 9

what happens to diploid cells when they are running low on nitrogen?

Answer 9

they will undergo meiosis and spore formation

Question 10

what is an ascus?

Answer 10

the result of four haploid spores – greater resistance to environmental factors than stationary phase cells

Question 11

what are the 4 morphogenic aspects of the yeast cell cycle?

Answer 11

1. bud site selection
2. polarity
3. pattern
4. rate of growth

Question 12

where does budding/growth occur in the yeast?

Answer 12

on yeast’s cell wall, where new cell material is being synthesized and cell wall remodeling enzymes are delivered

Question 13

what type of metabolism does S. cerevisiae use?

Answer 13

carbon metabolism

Question 14

how are compounds required for carbon metabolism, transported through the phospholipid membrane?

Answer 14

yeast secretes invertase or galactosidase to break up disaccharides, which causes the carbohydrates to undergo extracellular hydrolysis

Question 15

what is the importance of maltose in yeast?

Answer 15

important for bread-making and brewing. serves as an important carbon source for yeast

Question 16

how is maltose transported across the membrane?

Answer 16

actively transported and then hydrolyzed via alpha-glucosidase (maltase) into two glucose molecules. glucose is then catabolized via the glycolytic pathway

Question 17

how is sucrose metabolized via carbon metabolism?

Answer 17

hydrolyzed into fructose and glucose by Sc by an enzyme called invertase

Question 18

what happens if sucrose is hydrolyzed in the periplasmic space of Sc?

Answer 18

results in the formation of hexoses which can easily be taken up by hexose transporters

Question 19

Are glucose and hexoses further catabolized?

Answer 19

yes, they’re further catabolized into pyruvate via glycolysis. no net oxidation.

Question 20

what makes up the cell wall of Sc?

Answer 20

glucans (50% of the cell wall), mannoproteins (40% of the cell wall), and chitins (10% of the remaining cell wall)

Question 21

what are the cell wall layers of Sc?

Answer 21

homogenous inner layer (plasma membrane), and a fibrillar outer layer implanted in the inner layer

Question 22

what is Aspergillus oryzae?

Answer 22

a mold mainly used in East Asian cuisine to ferment soybeans, make soy sauce, miso, and break down rice starches into sugars for making sake. secretes a selection of amylases that extracellularly degrade starch.

Question 23

Aspergillus oryzae overall reaction in fermentation

Answer 23

starch converted to glucose using amylase

Question 24

what are the three categories of amylase species?

Answer 24

1. endomylase
2. exomylase
3. debranching enzyme consisting of a whole family of amylases

Question 25

what type of fungi is Aspergillus oryzae?

Answer 25

filamentous fungi

Question 26

conidium

Answer 26

a spore that is produced asexually by A.oryzae fungi at the tip of a specialized hypha that is capable of growing into a multicellular organism

Question 27

germ tube

Answer 27

what the conidium swells into if conditions are right.

Question 28

hyphae

Answer 28

what the germ tube forms into. individual sections that are partitioned by septa and constitute multicellular filamentous fungii

Question 29

what is the function/location of the pore?

Answer 29

the pore is located in the middle of each septum and is responsible for communication between cells

Question 30

function of woronin bodies?

Answer 30

plug the pore if one cell is killed or damaged. Woronin bodies are grouped near the septum

Question 31

spitzenkorper

Answer 31

accumulates and secretes vesicles containing secretory enzymes

Question 32

where is the spitzenkorper located

Answer 32

present in the hyphal tip region

Question 33

how are high levels of amylase in Aspergillus oryzae maintained?

Answer 33

The secretion vesicle is endocytosed immediately after fusion with the cell membrane and immediately recycled for incorporation into new secretion vesicles

Question 34

what is conidiophore?

Answer 34

a special cell that produces conidium to spread the mold (A. oryzae)

Question 35

process of spreading conidium?

Answer 35

nutrients are passed up the hyphae and up into the budding conidia. when conditions are right the conidium prepares to germinate

Question 36

what do vacuoles do in the process of spreading the mold?

Answer 36

appear and grow as conidium begin to swell, aiding in the physical extrusion of the cytoplasm at the tips of the germ tubes

Question 37

Other molds (3)

Answer 37

1. Geotrichum candidum 2. Penicillium candidum 3. Penicillium roqueforti

Question 38

Geotrichum candidum

Answer 38

rapid growing mold that prevents unwanted mold growth in moist cheeses. Geo15 is mild and Geo17 is very mild

Question 39

Penicillium candidum

Answer 39

produces a fuzzy white mold on the surface of bloomy rind cheeses including brie, camembert, coulommiers, and french goat cheeses

Question 40

penicillium roqueforti

Answer 40

creates the colored veins and surfaces and is a major contributor to the flavor in blue cheeses including gorgonzola, roquefort, and stilton. colors are grey, green, and blue.

Question 41

what do traditional fermentations usually rely on?

Answer 41

a mix of yeast, mold, LAB, and AAB

Question 42

which bacteria are located on the surfaces of food, and which ones are on the inside?

Answer 42

mold and AAB are usually on the surface, while LAB and yeasts are internal

Question 43

what is sake?

Answer 43

a traditional japanese alcoholic drink. also known as japanese rice wine

Question 44

what is the ABV % of sake?

Answer 44

18-20%

Question 45

how is sake made?

Answer 45

koji converts starches in rice into sugars. yeast is also used.

Question 46

what is fukuyama pot vinegar

Answer 46

a traditional Japanese rice vinegar

Question 47

how is fukuyama pot vinegar made?

Answer 47

rice and koji are added without additional microorganisms to a loosely capped large pot and laid in an open-air field

Question 48

what are the reaction steps in the production of Fukuyama Pot Vinegar?

Answer 48

1. Saccharification 2. Alcoholic fermentation 3. Acetic Acid fermentation 4. Lactic acid fermentation

Question 49

What is kefir?

Answer 49

a fermented milk beverage

Question 50

what kind of fermentation produces kefir?

Answer 50

inoculated fermentation. to produce this beverage, milk is inoculated with kefir grains that harbor LAB, AAB, and yeast (and sometimes molds)

Question 51

what are two examples of traditional fermented products?

Answer 51

Kefir and Fukuyama pot vinegar

Question 52

what do kefir grains consist of?

Answer 52

water and water-insoluble kefiran that is an extracellular polysaccharide that is produced by the LAB

Question 53

what type of fermentation are milk kefir grains usually used in to start a culture?

Answer 53

via back slopping

Question 54

what is kefiran?

Answer 54

a heteropolysaccharide composed by equal proportions of glucose and galactose and is mainly produced by Lactobacillus kefiranofaciens

Question 55

what additional species o helps with greater production of kefiran?

Answer 55

saccharomyces sp. | shows the importance of symbiotic relationships between yeast and bacteria

Question 56

what LAB are involved in kefir?

Answer 56

lactobacillus, lactococcus, streptococcus, and leuconostoc

Question 57

what are LAB responsible for in kefir

Answer 57

increasing the acidification

Question 58

what yeasts are generally included in kefir?

Answer 58

Saccharomyces, Kazachstania, Kluyveromyces, Torulaspora, Pichia, Lachancea, and Yarrowia

Question 59

are AAB found in kefir?

Answer 59

occasionally, but if there is presence of AAB there is no effect on the quality of the kefir

Question 60

why is it important to be careful about what you read about probiotics?

Answer 60

a lot of fake news on what probiotics due, such as curing cancer.

Question 61

what are the advantages of probiotics?

Answer 61

1. antimicrobial properties 2. anti carcinogenic properties 3. improves lactose tolerance 4. lowers cholesterol 5. improves GI system