Biology - Online Test
Q1.
Assertion: UAA codon is a termination codon.
Reason: If in a mRNA, a termination codon is present, the protein synthesis stops abruptly whether the protein synthesis is complete or not.
Answer : Option C
Explaination / Solution:
UAA of mRNA do not code for any amino acids so it is a termination codon. If termination codon is present on mRNA, the protein synthesis stops abruptly at that point.
Q2. The yellowish coloured milk secreted from the breast shortly after birth of the baby is called
Answer : Option B
Explaination / Solution:
After parturition, mammary glands start producing milk. The yellowish coloured milk is called colostrums. This milk contains antibodies that provide immunity to newly born baby.
Q3. Assertion: Replication and transcription occur in the nucleus but translation occurs in the cytoplasm.
Reason: mRNA is transferred from the nucleus into the cytoplasm where ribosomes and amino acids are available for protein synthesis.
Reason: mRNA is transferred from the nucleus into the cytoplasm where ribosomes and amino acids are available for protein synthesis.
Answer : Option B
Explaination / Solution:
Synthesis of RNA from DNA is called transcription and it occurs in the nucleus of eukaryotic cells.
DNA replication occurs in the cytoplasm of prokaryotes and in the nucleus of eukaryotes. Regardless of where DNA replication occurs, the basic process is the same.
Synthesis of protein from RNA is called translation and it occurs in the cytoplasm of eukaryotic cells.
messenger RNA (mRNA) is a molecule in cells that carries codes from the DNA in the nucleus to the sites of protein synthesis in the cytoplasma (ribosome) where they can be joined together in specific order to make a specific protein.
Q4. Mother’s milk during initial days of lactation is rich in …….. Antibodies.
Answer : Option C
Explaination / Solution:
After the birth of child, lactation starts in the mammary glands. The milk released in initial few days is called colostrum. Colostrum contains IgA antibodies that provide immunity to disease.
Q5. Transcription is the coping of genetic information form DNA to mRNA and translation is the formation of polypeptide chain according to code to form protein. Which one follows the other?
Answer : Option C
Explaination / Solution:
In central dogma, transcription is the copying of genetic information present on a DNA to mRNA. This mRNA is used as template to produce protein by the process of translation. Thus, translation is always followed by transcription.
Q6. Several memory ducts joins to form wider memory ampulla which is connected to
Answer : Option B
Explaination / Solution:
Several memory ducts join to form wider memory ampulla which is connected to lactiferous ducts through which milk is sucked out.
Q7. Number of nitrogenous bases in a Codon is
Answer : Option A
Explaination / Solution:
A codon is a sequence of 3 nitrogenous bases located on mRNA that will pair up with the anticodon of tRNA to make the polypeptide (protein) I. 64 codons can be obtained from four nitrogenous bases if arranged in group of 3.
Q8. At the end of pregnancy, expulsion or delivery of foetus takes place due to
Answer : Option A
Explaination / Solution:
Expulsion or delivery of foetus takes place due to vigorous contraction of uterus at the end of pregnancy. Oxytocin hormone released from pituitary glands causes stronger contraction to cause expulsion of foetus.
Q9. If 30 percent of an organism’s DNA is thymine, then
Answer : Option C
Explaination / Solution:
Thymine and Adenine bond with each other so, they are equal in number. Sum of cytosine and guanine is equal to 100-60=40 percent. So, percentage of guanine is 40/2= 20 percent.
Q10. Pseudo dormancy differs from normal pregnancy in
Answer : Option D
Explaination / Solution:
Pseudo dormancy differs from normal pregnancy in absence of foetus in the uterus. Developmental change in endometrium, and development of ovum occurs during menstrual cycles.
