Penicillin is produced by P. chrysogenum in a fed-batch culture with the intermittent addition of glucose solution to the culture medium. The initial culture volume at quasi-steady state is V0 = 500 l, and glucose-containing nutrient solution is added with a flow rate of F = 50 l/h. Glucose concentration in the feed solution and initial cell concentration are S0 = 300 g/l and X0 = 20 g/l, respectively. The kinetic and yield coefficients of the organism are mm = 0.2 h-1 , KS = 0.5 g/l, and YX/S = 0.3 g dw/g glucose. Determine the concentration of cells at quasi-steady state when t = 10 h.

#Question id: 4319

#SCPH28 | Zoology

Why are BRCA1 and BRCA2 considered to be tumor-suppressor genes?

#Question id: 15219

#SCPH01 Biochemistry

#Question id: 12758

#SCPH06 I Botany

Refer to the following experiment, which is designed to test the co evolutionary relationships among an unpalatable butterfly (the  monarch),  a  palatable  butterfly  (the  viceroy),  and  a  butterfly  predator  (the  jay).  Monarch butterflies are reared on three diets: milkweed (their natural food), cabbage, and cabbage treated with an extract from milkweed leaves. Viceroy butterflies, mimics of monarchs, also are reared on three diets: willows (their natural food), cabbage, and cabbage treated with an extract from milkweed leaves. In trial 1 of the first experiment, adult butterflies reared on a particular diet are presented one at a  time  at  1-hour  intervals  to  jays  and  the  jays  are  allowed  to  feed.  Each jay is  fed  until  it refuses to eat the butterfly presented, but no more than 12 butterflies are presented to a jay during a particular test. Five birds are used for each test; therefore, up to 60 butterflies can be consumed for each diet test. The observer records the actual number of butterflies  eaten. In trial 2, the experiment is repeated 2 weeks later. In the second experiment, the butterflies are reared on the same diets as in experiment 1. However, when they are offered to jays, some jays receive a monarch  reared  on  milkweed  before  being  offered  the  butterflies  reared  on  the  experimental  diets;  the  other  group  of jays is  first given a viceroy reared on willow before being  offered the butterflies reared on the experimental diets. The initial butterfly offered is included in the total number eaten, but no more than 12 butterflies are presented to each jay.

The experimental design and the data indicate which of the following about the jays? 

#Question id: 3443

#SCPH28 | Zoology

The evolution of mating systems is most likely affected by

#Question id: 10524

#SCPH06 I Botany

Members of the Poaceae family, which includes all of the cereal crops, use benzoxazinoids, these alkaloids shows;

a) Alkaloids are derived from the tryptophan as constitutively produced defensive secondary metabolites

b) These benzoxazinoids such as DIBOA and its derivative DIMBOA are usually stored in the peroxisome

c) Upon damage, the inactive glycosides are hydrolyzed, generating glucosinolate, which are toxic not only to insect herbivores but also against pathogens

d) DIBOA and DIMBOA perform insecticidal and pesticidal activities

e) It can be inactivated by hydroxylation and N-glycosylation reactions

Which of the following combination is correct about benzoxazinoids alkaloids?