Bio 102 Lab 1 Exam
Based on the fermentation data, what is the growth rate in the second phase?
0.035(h^-1) The specific growth rate (u^max) can be determined from the ln(biomass) vs. time graph. Based on the data, the linear regression of the ln(biomass) vs. time graph is y=0.0358x + 0.4956. The slope (m) represents the specific growth rate, hence the slope (u^max) is 0.035(h^-1)
Based on the fermentation data, what is the value of the coefficient (Y_sx) under anoxic conditions?
0.10 g Dw/g glc You have successfully made a plot, showing that there is indeed a linear relationship between glucose and biomass. Based on the data, the linear regression of the biomass vs. glucose consumed graph is: y = 0.0985 + 0.01. The slope (m) correlates with biomass yield coefficient, and the coefficient (Y^sx) is 0.1 g Dw/g glc
How can we obtain cells for a cell culture?
- We culture stable cell lines - We take them from the animal or plant, making a primary culture - We use stem cells In this case, we will use a stable cell line that comes from a tumor. The advantage of using this kind of cell line is that the undergo limited growth under ideal conditions. Therefore, they can be cultured and used again and again
What is a hybrid
An offspring with parents of two different breeds also called crossing
DNA wound around histones forms a structure that looks like a beaded string. What is this structure called?
Chromatin Chromatin is a complex of DNA and histone proteins that form the chromosomes. To visualize chromatin, think of a long DNA strand wound around small nucleosomes, like a string of beads
What is stained in red?
Chromatin The chromosomes are stained in red
We used different fluorescent dyes to color specific parts of the cell and combined the resulting images. Which part is colored in blue?
Chromosomes In this slide, cells were dyed with three different colors. Chromosomes are blue, microtubules are red and the kinetochores are green
Metabolism can be divided into catabolic and anabolic reactions. How are these connected?
Catabolic reactions generate energy that anabolic reactions use Anabolic reactions utilize the energy generated by catabolic reactions to build big molecules such as DNA or proteins
Cell division is essential for any living organism. For which of these processes is it NOT essential?
Preservation Cell division is the key process in reproduction, tissue renewal, growth and development
What is an allele?
An alternative form of a gene Alleles are variants of the same gene, that are found in the same location on different chromosomes
Recalculate the yields, Y_sx of the anaerobic fermentation (0.10 g DW/g glc) to be in units of cmol/cmol instead of g/g
0.12 cmol DW/cmol glc Formula: Y_sx(cmol/cmol) = Y_sx(g DW/g glc) * Mw(glc)/Mw(biomass) Hence, Ysx = 0.10 g DW/glc * (30/24.6) cmol/g = 0.12 cmol DW/cmol glc
Based on the fermentation data, what is the slope (U_max) for the first growth phase, when pH=7 and temperature= 25 degrees C?
0.125 (h^-1) Specific growth rate correlated with slope from ln(biomass) vs. time. The linear regression equation of that graph is: y = 0.125x - 4.6034 m(slope) = specific growth rate, hence the specific growth rate is 0.125 (h^-1)
Based on the fermentation data, what is the growth rate (u_max) under anoxic conditions?
0.141 h^-1 The specific growht rate (u^max) can be determined from ln(biomass) vs. time graph. Based on the data, the linear regression of the ln(biomass) vs. time graph is: y = 0.1412x - 4.6004. The slope (m) correlates with specific growth rate, and the slope (u^max) is 0.141 (h^-1)
Based on the fermentation data, what is the value of the yield coefficient Y_sx?
0.18 g Dw/g glc You have successfully made a plot, showing that there indeed is a linear relationship between glucose and biomass. Based on the data, the linear regression of the biomass vs. glucose consumed graph is: y= 0.1821x + 0.0095. The slope (m) correlates with biomass yield coefficient, hence the coefficient (Y_sx) is 0.18 g Dw/g glc
What would an estimate of the q_eth of the anaerobic fermentation be?
0.23 g eth/(l*h) An estimate of the volumetric production of ethanol would be maximum ethanol concentration, divided by time. From the fermentation data, we know that the highest ethanol yield is 8.99 g/L at 38.3 h. Hence, the estimate q_eth of the anaerobic fermentation is: 8.99 g eth/L / 38.3 h = 0.23 g eth/(l*h)
Based on the fermentation data, what is the optimal growth rate u^max for the first growth pahse?
0.260(h^-1) The specific growth rate (u^max) can be determined from the ln(biomass) vs. time graph. Based on the data, the linear regression for the ln(biomass) vs. time is: y=0.2605x - 4.6034. The slope (m) correlates with specific growth rate, and the growth rate (u^max) is 0.26(h^-1)
Calculate the yields of CO2 in the anaerobic fermentation. (Remember that the CO2 numbers are calculation of the overall CO2 production. To calculate as a concentration you need to divide with the reactor volume of 1.8 liters)
0.27 cmol CO2/cmol glc You can calculate the yield of carbon dioxide from CO2 vs. glucose consumed. The linear regression of this graph is y = 0.486x + 3E-07. To get the yields of CO2, you must divide the slope (m) with volume of the fermentor. Hence, yields of CO2: 0.48 / 1.8 L = 0.27 cmol CO2/cmol glc
Based on the fermentation data, what is the value of the yield coefficient (Y_seth)?
0.36 g eth/g glc Based on the data, the linear regression of the ethanol vs. glucose consumed graph is: y = 0.3605x - 0.0003. The slope (m) correlates with ethanol yield coefficient, hence the Y_seth is 0.36 (g eth/g glc)
Find the coefficient for substract to ethanol (Y_seth) under anoxic conditions
0.45 g eth/g glc Based on the data, the linear regression of the ethanol vs. glucose consumed graph is: y = 0.45x - 0.00002. The slope (m) correlates with the ethanol yield coefficient, hence the Y_seth is 0.45 (g eth/g glc)
Recalculate the yield, Y_seth of the anaerobic fermentation (0.45 eth/g glc) to be in units of cmol/cmol instead of g/g
0.59 cmol eth/cmol glc If you calculate the yield in terms of cmol instead of g, the following is true: Yseth (cmol eth/cmol glc) = Yseth (g eth/g glc) x Mw(glc) / Mw(eth) Yseth (g eth/g glc) = 0.45 Mw (glc) = 30 g/cmol Mw (eth) = 23 g/cmol Yseth (cmol eth/cmol glc) = 0.45(g eth/g glc) x 30(g/cmol)/23(g/cmol) = 0.59 cmol(eth)/cmol(glc) Y_sx(cmol/cmol) = Y_sx(g DW/g glc) * Mw(glc)/Mw(biomass) Hence, Yseth = 0.45 g eth/g glc * (30/23) cmol/g = 0.59 cmol eth/cmol glc
Calculate all the glucose data into cmol. What is the number of cmol glucose at time = 10.42h and 24.07h?
0.66 and 0.57 Glucose at 10.42h is 19.65 g/L. In cmol: 19.65g/L / 30 cmol/L = 0.66 cmol Glucose at 24.07h is 17.04 g/L. In cmol: 17.04 g/L / 30 cmol/L = 0.57 cmol
What is the net result of one glucose molecule going through the Krebs cycle?
2 ATP molecules 6 CO2 molecules 8 NADH and 2 FADH2 molecules Glucose gets converted to two pyruvate molecules that each enter the Krebs cycle. So, everything you see on the poster is doubled. You will notice that the main products of the Krebs cycle are electron carriers. Electron carriers participate in redox reactions that you can see displayed
From what you learned about glycolysis, what is the ATP yield per each molecule of glucose under low oxygen conditions?
2 ATP molecules from glycolysis When oxygen is very low, the electron transport chain cannot proceed and aerobic respiration stops. Therefore, glucose goes through glycolysis and pyruvate is fermented into lactic acid
(Image) How many daughter cells are produced by each of these processes?
2 for mitosis, 4 for meiosis The end product of mitosis is 2 daughter cells, while meiosis produces 4 daughter cells
Have you noticed the checkpoints in the illustration of the cell cycle? A checkpoint in the cell cycle is a control point where stop and go signals regulate the cycle. How many checkpoints are there in the cell cycle?
3 The first checkpoint is the "start" or "G1 checkpoint" in late G1. The second is the "G2 checkpoint" in late G2. The third is during the "metaphase-to-anaphase transition" in the mitosis (M) phase
In summary, glycolysis breaks down glucose into 2 pyruvate molecules. How many carbon atoms does one molecule of pyruvate contain?
3 carbon atoms
What is the molecular weight of glucose, and ethanol in g/cmol? (hint: you can find the molecular weights of the elements in the theory page)
30 g.cmol and 23 g/cmol You can calculate the molecular weight in cmol, by using the molecular formula in terms of cmol Glucose is CH2O, hence the molecular weight: 12 + 2 + 16 = 30 g/cmol Ethanol is CH3O0.5, hence the molecular weight: 12 + 3 + 8 = 23 g/cmol
From the previous analysis, we found out that the slope (u_max) for the first growth phase is 0.125(h^-1). So what is the doubling time?
5.55(hours) T2 = ln(2)/u Where ln(2) = double population size, u=growth rate, T2=doubling time Doubling time = ln(2)/0.125(h^-1)
What percentage of genetic information is passed on from parents to their offspring?
50% from each parent
We would like to start the fermentor with a biomass concentration of 0.01 DW g/l. For this strain this translates into an OD_600 value of 0.024. The OD_600 of your inoculum is 6.4. The working volume in the bioreactor is 1.8 liters. What volume of the inoculum do you need to add the fermentor?
6.75 ml Use the formula V1 * C1 = V2 *C2 V= volume C= concentration of biomass (OD_600)
Which of the onion root cells is in telophase?
A During telophase, the daughter nuclei are formed. The cell plate, the precursor of the cell wall, also begins to grow, marking the start of cytokinesis
What must a growth media contain?
A carbon- and nitrogen- source, phosphor and trace metals (Ka, Mg, Cu)
Individual chromosomes that are inherited from each of the parents are called
A homologous pair The two chromosomes of a homologous pair are individual chromosomes that were inherited from different parents
The yield of ethanol in cmol for the aerobic fermentation was 0.47 cmol eth/cmol glc, and the volumetric production rate was q_eth = 0.31 g eth(l*h) How would you choose to perform the fermentation if you want to produce ethanol as fast as possible?
Aerobic fermentation, because the volumetric production is highest From our results we can see that the volumetric production rate was highest for the aerobic fermentation. High volumetric production rate is important for high value products
After glycolysis, the pyruvate molecules can follow two different metabolic routes: aerobic and anaerobic respiration. What is the main difference between these?
Anaerobic respiration does not need oxygen to occur and aerobic respiration does Anaerobic respiration can take place in the presence or absence of oxygen. Whereas oxygen is essential for aerobic respiration
The cell on the right side of this slide is currently in
Anaphase I In Anaphase I, spindle microtubules pull the homologous chromosomes apart. The sister chromatids are still attached at the centromere
Individuals with the appropriate number of chromosomes are called euploid, whereas individuals with an error in the number of chromosomes are described as
Aneuploid An aneuploid organism has an abnormality in the number of chromosomes. Aneuploidies include loss of chromosomes (for instance a monosomy, the loss of one chromosome), and also gain of extra chromosomes (for instance, a trisomy)
(picture) Which of the onion root cells is in prophase?
B In prophase, the chromosomes condense and the nucleus starts to disappear
Unicellular organisms such as bacteria depend on asexual reproduction. Why is sexual reproduction so common in higher multicellular organisms such as humans?
Because it creates genetic variation in the population The essence of sexual reproduction is the random selection of half of the diploid chromosome set to make a haploid gamete, followed by fusion of two haploid gametes from two different individuals to produce a diploid cell, the embryo In this way diversity of the offspring is ensured, which is crucial to allow new individuals to be able to adapt to changes in their environment
Which parameters could you use to measure the effect of exercise on cellular respiration in mice?
Blood lactic acid concentration Blood glucose concentration Oxygen consumption These are all parameters that we can use in the lab. Oxygen consumption levels will tell us about the oxidative phosphorylation process
Which protein does the cell need for cell cycle progression?
Both cyclins and cyclin-dependent kinases The cell cycle is regulated mainly by two types of proteins: cyclin-dependent kinases (CDKs) and cyclins In order to be active, CDKs need to be attached to a specific cyclin, forming a cyclin-CDK complex. Therefore, we need both cyclins and cyclin-dependent kinases
Mitosis and meiosis are both involved in reproduction. Asexual reproduction only involves mitosis, while sexual reproduction involves
Both mitosis and meiosis Sexual reproduction requires gametes created by meiosis. The gametes from two organisms are combined, creating a zygote. Mitosis is important for sexual reproduction indirectly. Mitosis allows the zygote to develop into a mature individual
(Four pics of different chromosomes aligned)
C In mitosis, after duplication, homologous chromosomes remain separated. On the contrary, in meiosis they are tightly paired forming what is called a synapsis. This allows crossing over, which is an exchange of chromosomal segments between non-sister homologous chromatids (one maternal and one paternal chromatid). Synapsis and crossover are very important processes in the generation of genetic diversity
What is the molecular formula of glucose, and ethanol in cmol?
CH_20 and CH_3O_0.5 You simply take the molecular formula, and normalize to the number of carbon atoms Glucose is C6H12O6, it becomes CH20 in cmol Ethanol is C2H6O, it becomes CH3O0.5 in cmoll
(another 4 pics of chromosomes aligned)
D In meiosis, in Metaphase I to be exact, homologous chromosomes come together to pair along their entire length. This pairing doesn't occur in mitosis, and is the key step in the creation of haploid daughter cells
Which of the onion root cells is in anaphase?
D In anaphase, the sister chromatids of each chromosome are separated. The daughter chromosomes move to the ends of the cell
(Picture) Which of these batches could be contaminated?
D- The contaminants usually growth very fast, therefore, a high CO2 level, and high biomass relative to product (in this case ethanol) indicates the presence of contaminants
The cell contains two sets of chromosomes (2n). What is the correct name for such cells?
Diploid Any cell with two chromosome sets (2n) is called a diploid cell
What action would you recommend to the point guard?
Drink a maltose sports drink Since maltose is composed of two glucose molecules, this will give the point guard some quick energy. We'll make sure to do that
In some of the cells you can see clear chromosomes while others only contain a red sphere. How can you explain these red spheres?
Due to uncondensed chromosomes The nuclei of cells in interphase are almost uniformly red because the chromatin is all over the nucleus. In the mitotic phase, the chromosomes condense, and we see them as bright red
We are going to need a lot of cells for our experiments. How do we produce new cells?
Duplicate existing cells
What type of cell do you see?
Egg Egg cells are 0.1 mm in size, or equivalent to a dot, which makes them the largest cell in the female body. The egg cell is the most remarkable of human cells; once activated (by fertilization), it can give rise to a complete new individual. The egg has a round shape and nucleus which is surrounded by cell plasma
Most of your cells contain 46 chromosomes. You inherited 23 from your mother and 23 from father. Before the cells divide, each other them condenses into an x-shaped duplicated chromosome, which can be seen with a light microscope. At this stage, what does each of these chromosomes NOT contain?
Exactly four histones At the beginning of cell division, each chromosome consists of two sister chromatids, because they have already been duplicated. Each of these chromatids consists of one DNA helix wrapped around many histone protein complexes. This is the chromatin. Each DNA helix consists of two complementary DNA strands. These two different molecules perfectly fit together like a zipper due to their base pairing. This property of DNA makes it a stable source of the cell's building plans
The union of two gametes from two individual organisms is called
Fertilization Sexual reproduction requires fertilization, the union of two gametes from two individual organisms
Which phase of the cell cycle is represented by number 1 in the diagram?
G1 phase G1 phase is part of interphase. The goal of interphase is to grow by producing proteins and cytoplasmic organelles such as the endoplasmic reticulum. The G1 phase follows the division of the original cell and serves the resulting daughter cells to grow and prepare for the next division
Which checkpoint checks for DNA damage after replication?
G2 checkpoint DNA is replicated in the S phase. Before the cell enters mitosis, DNA has to be checked for any damage at the G2 checkpoint in late G2 phase
Which phase of the cell cycle is represented by number 3?
G2 phase G2 phase is the last part of interphase. In this phase, there is a checkpoint where the cell makes sure everything is ready before it can proceed to the mitotic phase. In particular, the correct replication of the DNA during the S phase is checked
What is the name of the haploid cells that carry the genetic information from each parent?
Gametes Gametes carry 50% of the genetic information from each parent. The human gametes are called sperm and eggs
Ova and sperm are gametes. Unlike somatic cells (the rest of the cells in our body), they only contain a single set of chromosomes, what type of cells do we, therefore, consider them?
Haploid Haploid cells contain only a single set of chromosomes, or a homolog from each pair (n). The letter "n" is used to refer to haploid systems, so 2n refers to diploid systems
(Image) What is the correct description of the daughter cells after meiosis?
Haploid Meiosis produces haploid (n) daughter cells, while mitosis produces diploid cells (2n). This is the most important difference between mitosis and meiosis Haploid means the cell has only one set of chromosomes. In humans, haploid cells have 23 chromosomes, while diploid cells have 46 chromosomes
The first step of glycolysis consumes energy. Two high energy ATP molecules phosphorylate glucose. How do ATP molecules store energy?
High energy bonds between phosphate groups The three-phosphate tail of the ATP molecules is responsible for energy storage. High energy bonds between the phosphate groups break to allow the energy to be utilized
In meiosis a diploid cell divides twice yielding four haploid daughter cells. In meiosis I what separates?
Homologous chromosomes During meiosis I, the homologous chromosome pairs separate. However, the sister chromatids remain together. Thus, the result of the first meiotic division are haploid cells with duplicated chromosomes
Note about Trisomy
Humans have 46 chromosomes In trisomy 13, each cell in the body has three copies of chromosome 13 instead of two copies. This trisomy is characterized by facial dysmorphism, brain malformations, severe psychomotor retardation, and other significant organ defects. Most of the children with trisomy 13 die within the first year of life
Why is the Krebs cycle so important if it only produces 2 ATP molecules?
It produces reducing agents for the electron transport chain Electron carriers are reducing agents. This means that they donate electrons. The Krebs cycle produces 8 NADH and 2 FADH2 molecules that are reducing agents and bring electrons to the electron transport chain
Mitosis can proceed from metaphase to anaphase if all sister chromatids are properly attached to the microtubules (via the kinetochore). Which checkpoint is responsible for checking this?
M checkpoint During the metaphase checkpoint, the cell checks that microtubules of the mitotic spindles are properly attached to the kinetochore. If the cell passes this checkpoint, sister chromatids will begin to separate, leading to the completion of mitosis and cytokinesis
Which experiment would you perform to test what happens under extreme exercise conditions?
Make the mouse run at high speed with low oxygen availability To test extreme conditions we could either make the mouse run at high speed for a long time or at a high speed with low oxygen availability
Based on the slide analysis, what would be the sex of the baby?
Male It will be a boy because you can see chromosome X (orange) and chromosome Y(yellow). Males have one X and Y, they are XY. Females have two chromosome X and no Y, they are XX
Inherited genetic disorders, such as aneuploidy and chromosomal structural rearrangements can arise when chromosomes behave abnormally during
Meiosis Inherited disorders can arise when chromosomes behave abnormally during meiosis
Prior to the fertilization process, higher eukaryotes have to produce reproductive cells (gametes). Through which type of cell division are the reproductive cells produced?
Meiosis Meiosis is the type of cell division that gives place to gametes. Chromosomes are duplicated and then separated into four reproductive cells that have exactly half the number of chromosomes of the parents
We use lily as a model organism to observe the stages for meiosis. Earlier we used acetocarmine as a stain. This stain gives the chromosomes a red color. Now press the "explore" button. Which phase are the cells currently in?
Metaphase I During Metaphase I, the homologous chromosomes are arranged in the center of the cell with the kinetochores facing opposite poles. You can visit the theory page and try to see the differences between metaphases I and II
Which phase are the cells currently in?
Mitosis phase Mitosis is part of the cell cycle process. During mitosis the chromosomes (blue) in the cell nucleus are separated into two identical sets of chromosomes
(Fermentation overview graph) Based on the graph, do you think the yeast cells have ceased to grow?
No, because biomass concentration and CO2 is still increasing The fermentation is not complete, as can be seen by the rise in biomass and CO2 They cannot grow without a substrate, however glucose is not the only substrate for yeast. Where there was no more glucose, the yeast cells started to use the ethanol as substrate. When a microorganism grows on two substrates, one at a time, it is called diauxic growth. Ethanol is not as good a substrate as glucose, and therefore the growth and CO2 increase is lower
Errors in meiosis are the cause of chromosomal abnormalities. Errors that occur when pairs of homologous chromosomes or sister chromatids fail to separate during meiosis are called
Nondisjunction Nondisjunction occurs when pairs of homologous chromosomes or sister chromatids fail to separate during meiosis Nondisjunction can occur during either meiosis I or II
You may have heard that yeast produce ethanol anaerobically (without air). Why do yeast cells produce ethanol under aerobic conditions (with air)?
Overflow of carbon source, makes the yeast convert the excess carbon Even when oxygen is present, S. cerevisiae converts overflow of glucose to ethanol. This way the glucose is made unavailable for other microorganisms. When glucose is limited again, the yeast can digest the ethanol. Also, the ethanol itself is poisonous to most other microorganisms and therefore ethanol also works as a defense mechanism
What is oxygen used for in cellular respiration?
Oxygen is the last electron acceptor in the oxidation of electron carriers In the electron transport chain, electrons are transported from the NADH and FADH2 obtained during glycolysis and the Krebs cycle to oxygen
During interphase, homologous chromosomes are
Replicated Interphase consists of the G1, S, and G2 phases. in the G1 phase cells are focused on growth. In the S phase, the homologous chromosomes are replicated. Finally, in the G2 phase, cells undergo the final preparation for cell division
What phase of the cell cycle is represented by number 2 in the diagram?
S phase DNA synthesis takes place between the two gap phases. DNA is only replicated during the S phase
The correct term to fill in box D is
Sister chromatids A homologous chromosome consists of sister chromatids. Sister chromatids are two copies of one chromosome, closely associated along their lengths
To yield haploid cells, in meiosis II what separates?
Sister chromatids In Meiosis II the connected sister chromatids in the haploid cells, from Meiosis I will be split to form 4 haploid cells
At this stage, the two identical copies of single chromosomes are aligned at the midline of the cell. What is the correct term for these copies of single chromosomes?
Sister chromatids This slide shows an early stage of mitosis (metaphase). At this stage, the copying of the DNA is already done, and the two identical copies of single chromosomes are still attached to each other as sister chromatids. In later stages of mitosis, sister chromatids will separate into individual chromosomes
Fluorescent microscopy can be used to visualize cellular structures in very high contrast. What do fluorescent dyes stain to make this possible?
Specific molecules The fluorescent dyes bind specifically to certain molecules in the cell, such as DNA or microtubules. If you record only the light emitted by this stain, you can produce images with very high contrast
What type of cell do you see?
Sperm Sperm cells are one of the smallest cells in the male body. The sperm cells consist of a head, a midpiece and tail
Which type if cells undergo meiosis?
Sperm cells Meiosis only occurs during the formation of gametes: female egg cells and male sperm cells. Mitosis happens in all other cells
What would happen if organisms produced reproductive cells through mitosis instead of meiosis?
The chromosome number of that species will double with each generation If the reproductive cells were produced using mitosis, they would have two sets of chromosomes (2n). Therefore, the combination of the reproductive cells of the parents combined will produce an embryo with double the number of chromosomes (4n). The number of chromosomes will double every generation. This alteration will usually end up in an abortion or in a syndrome if the offspring survives
What two processes are coupled throughout the ETC that together make up oxidative phosphorylation?
The oxidation of electron carriers and the phosphorylation of ADP Electron carriers are oxidized throughout the electron transport chain and the final step is the phosphorylation of ADP by ATP synthase to produce ATP.
Based on your examination, what is your conclusion?
The poison inhibits cell division You can see that after 24 hours the control cells have divided and the number of cells has increased. Conversely, cells exposed to the poison did not divide much after 24 hours. This demonstrates that the poison inhibits the cell division
Based on the graph, what can you say about the growth of yeast?
The yeast shows diauxic growth The yeast have diauxic growth, meaning that there are two growth phases. In the first glucose is used as substrate, and bio,ass and ethanol is synthesized. When there is no more glucose, the yeast degrade the ethanol it order to survive and keep producing biomass
What is the genotype of an individual?
Their genes Genotype is the genetic makeup of an organism. The genotype is like a construction plan, and the phenotype is the resulting building
What is the phenotype of an individual?
Their observable characteristics
Why do you sterilize the fermentor?
To ensure mono-cultivation of yeast In real life the fermentors are put into a device called an autoclave. Under high pressure, the fermentor is heated up to 121 degrees Celcius. This process usually takes a few hours. After the autoclaves treatment it's important to keep the fermentor sterile
What is the primary reason yeast cells produce ethanol under anoxic (without oxygen) conditions?
To regenerate NAD+, and maintain redox-balance Under anoxic conditions, the cells cannot make oxidative phosphorylation. The yeast therefore rely only on substrate level phosphorylation Glucose + 2NAD+ + 2ADP --> 2Pyruvate + 2NADH + 2ATP
How do we represent dominant and recessive alleles?
Uppercase letters for dominant, lowercase letters for recessive alleles
What is the correct stoichiometric equation?
Y_sc*[CO2] + Y_seth*[eth] + Y_sx*[x] - [Glc] = 0 In the stoichiometric equation, the yield coefficients and the products are positive and the substrates are negative
Set up the carbon balance. Does the carbon balance?
Yes, Y_sc + Y_seth + Y_sx - 1 = 0 The carbon balance in cmol. can be simplified to: Y_sc + Y_seth + Y_sx - 1 = 0 If you do the calculation, we can see that it almost results in zero. There can be many reasons for the carbon not balancing. Yeast also produces many other compounds that are secreted into the media, that we did not test for. Examples are citric acid and pyruvate that are often found in small amounts
Based on the slide analysis, do you think the baby would have any chromosome abnormalities?
Yes, he would have trisomy 13 Under a fluorescence microscope you can evaluate the number of chromosomes that have been colored with a specific fluorochrome. In this case you can see three green spots which refer to the three copies of chromosome 13
Can you explain why the growth rate (u_max) is higher in the aerobic fermentation?
Yes, it is because oxidative phosphorylation yields more energy than substrate level phosphorylation Substrate level phosphorylation only yields 2 ATP per glucose molecule, while oxidative phosphorylation yields about 38 ATP
Yeast cells grow very fast. Which mathematical equation describes their growth?
x(t) = x_0*e^(u*t)