The interaction of selection and inbreeding in determining the incidence of autosomal recessive diseases. Consider a gene in which recessive mutations occur at a rate of 10^-5. Assume a selective disadvantage S of 0.4 in homozygotes for the recessive allele. Would q be expected to rise, fall, or remain unchanged during the first 10 generations after the cessation of inbreeding, Briefly justify your answer. What numerical value would q approach after thousands of generations with no inbreeding?

#Question id: 10198

#Unit 6. System Physiology – Plant

The response of photosynthesis to light in a C3 plant some given effect shows in dark as well as in the light, which of the following effect is not true?

#Question id: 10199

#Unit 6. System Physiology – Plant

Some differences is found between plants that normally grow in full sunlight and those that grow in the shade given below;

  COLUMN A                                                              COLUMN B

  A- SHADED PLANTS                          i-  Light compensation points range from 10 to 20 μmol m–2 s–1

  B- SUN PLANTS                                 ii-  low light Compensation point and have lower maximum photosynthetic rates

                                                               iii-  Light compensation points range from 1 to 5 μmol m–2 s–1

                                                               iv-  the respiration rates in plants are very low

                                                                v-  Plants CO2 assimilation take place very late

Match the correct combination of column A with the column B;

#Question id: 10200

#Unit 6. System Physiology – Plant

Following are some facts regarding C3 and C4 Plants

a.) In C4 plants the reduction is caused by the additional energy requirements such as 1 ATP per CO2 from C3 plants

b.) C4 leaves are exposed to low O2 concentrations, the quantum yields for CO2 fixation remain constant while C3 leaves are exposed to low O2 concentrations quantum yield increases

c.) C3 leaves are exposed to low O2 concentrations, photorespiration is maximized

d.) Plant with the C4 metabolism need more rubisco than C3 plants to achieve a given rate of Photosynthesis

Which of the following combination would be correct?

#Question id: 10201

#Unit 6. System Physiology – Plant

Chloroplasts orientation in Algae is controlled by

#Question id: 10202

#Unit 6. System Physiology – Plant

What will happen if C4 leaves are exposed to low O2 concentrations?

#Question id: 10203

#Unit 6. System Physiology – Plant

Light-response curves of photosynthetic carbon fixation in sun and shade plants. Typically, shade plants have a low light compensation point and have lower maximum photosynthetic rates than sun plants this is because respiration rates in shade plants are very low; which of the following graph is correct?