Download App

Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYMolecular Basis of Inheritance4 Marks
Question
Describe the process of translation during protein synthesis
✓

Answer

→ Prokaryotic Translation involves following step.
(i) Activation of amino acid
(ii) Formation of polypeptide chain
→ Activation of amino acid
→ In the presence of aminoacyl tRNA Synthatare (Enzyme), a specific amino acid reacts with ATP
→ Amino acid + ATP + Enzyme $\xrightarrow{ Mg ^{2+}}$ Amino acid amp Enzyme (complex) + PPi
→ In aminoacylation of tRNA, the a.acid AMP - E (complex) reacts with uncharged t-RNA.
→ Amino acid - AMP (complex) - Enzyme + t-RNA → Amino acid (Charged) - t-RNA + Enzyme + PPi
→ Formation of Polypeptide chain
→ The cellular factory responsible for synthesising proteins is the ribosome.
→ The ribosome consists of structural RNAs and about 80 different proteins.
→ In its inactive state, it exists as two subunits; a large subunit and a small subunit.
→ When the small subunit encounters an mRNA, the process of translation of the mRNA to protein begins.
→ There are two sites in the large subunit, for subsequent amino acids to bind to and thus, be close enough to each other for the formation of a peptide bond.
→ The ribosome also acts as a catalyst (23S rRNA in bacteria is the enzyme - ribozyme) for the formation of peptide bond.
→ A translational unit in mRNA is the sequence of RNA that is flanked by the start codon (AUG) and the stop codon and codes for a
polypeptide.
→ An mRNA also has some additional sequences that are not traslated and the referred as untranslated regions (UTR). The UTRs are present at both 5'-end (before start codon) and at 3'- end (after stop codon). They arerequired for efficient translation process
→ Translation has 3 steps
• Initiation
→ For initiation, the ribosome binds to the mRNA at the start codon (AUG) that is recognised only by the initiator tRNA.
• Elongation
→ The ribosome proceeds to the elongation phase of protein synthesis. During this stage, complexes composed of an amino acid linked to tRNA, sequentially bind to the appropriate codon in mRNA by forming complementary base pairs with the tRNA anticodon.
→ The ribosome moves from codon to codon along the mRNA.
→ Amino acids are added one by one, translated into Polypeptide sequences dictated by DNA and represented by mRNA.
• Termination
→ At the end, a release factor binds to the stop codon, termination translation and releasing the complete polypeptide from the ribosome.
Image

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Case study (4 Marks)" from Molecular Basis of Inheritance→Molecular Basis of Inheritance — all question types→BIOLOGY STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

Explain structure and working of biogas plant with diagram.
→
Explain bioreactor with diagram.
→
Read the following and answer any four questions from (i) to (v) given below:

Over population causes number of family problems. Strategies like birth control methods help to control population explosion. Natural methods of birth control do not involve medications or devices to prevent pregnancy, but rather rely on behavioural practices and/ or making observations about menstrual cycle.

  1. Which method helps in contraception by temporary absence of sex?
  1. Coitus interruptus.
  2. Withdrawal method.
  3. Rhythm method.
  4. Lactational amenorrhea method.
  1. Assertion: The effectiveness of coitus interruptus method is limited.

Reason: Some sperms may pass into vagina before ejaculation.

  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
  1. Why is lactational amenorrhea effective for about 4-5 months after parturition?
  1. Ovulation occurs on about the 14th day of menstruation.
  2. Ovulation does not occur during intense lactation.
  3. This method inhibits mobility of sperms.
  4. Both (b) and (c).
  1. Which fact is not the basis of periodic absence method of birth control?
  1. Ovum remains alive for about 1-2 days.
  2. Ovulation occurs on about 14th day of menstruation.
  3. Sperms survive for about 3 days.
  4. Alteration in uterine endometrium.
  1. On which days of menstrual cycle should coitus be avoided to prevent fertilisation?
  1. 10-17
  2. 6-13
  3. 1-5
  4. 15-28
→
Explain any two X-linked recessive disorder?
→
What is spermatogenesis? Briefly describe the process of spermatogenesis.###Explain the process of spermatogenesis. (Diagram is not required)###According to spermatogenesis (i) Development of sperm from primary spermatocytes. Explain it. (ii) Role of hormones which secreting from pituitary gland (iii) Structure of sperm (Diagram is not necessary)
→
Why are vectors needed for replication of DNA during rDNA technology?
→
Write a note Lac operon
→
Read the following and answer any four questions from (i) to (v) given below:

Medical termination of pregnancy is termination of pregnancy before the fetus become viable. To reduce the incidence of illegal abortion and consequent maternal mortality, MTP Amendment Act, 2017 was enacted by the government of India. About 40-50 million MTPs are done in a year all over the world.

  1. Abortion can be safely done for about ______ weeks of pregnancy.
  1. 4
  2. 12
  3. 8-10
  4. 15-18
  1. How is MTP helpful in decreasing human population?
  1. By aborting normal female fetus.
  2. By aborting normal female fetus.
  3. By getting rid of unwanted pregnancies.
  4. None of these.
  1. Select an incorrect statement for MTP.
  1. Second trimester abortions are more risky than first trimester.
  2. It is being misused to abort normal female fetus.
  3. It helps to get rid of unwanted pregnancies.
  4. Child detected with congenital heart disease cannot be aborted.
  1. MTP was legalised by Government of India in:
  1. 1971
  2. 1982
  3. 1973
  4. 1991
  1. Assertion: MTPs are safe during first trimester of pregnancy.

Reason: After first trimester, fetus become intimately associated with the maternal tissues.

  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
→
Explain the inheritance of one gene by Punnett Square ?
→
Read the following and answer any four questions from (i) to (v) given below:

Siddharth is a chain smoker. He got into this habit in early adolescence due to peer pressure and gradually got addicted to this habit. Its now almost 20 years he is into the habit of smoking. Since few months he is experiencing pain in chest, shortness of breath, wheezing and chronic cough with phlegm. He seeked advice of a medical practitioner who diagnosed him with lung cancer. Based on the above information, answer the following questions.

  1. What do you think is the possible carcinogen responsible for Siddharth's lung cancer?
  1. Nitrosamines
  2. Benzo(a)pyrene
  3. Hydrazine
  4. All of these
  1. How is lung cancer diagnosed?
  1. Computerised tomography scan
  2. Sputum cytolog
  3. Biopsy of lung tissue
  4. All of these
  1. From which of the following type of cancer is Siddharth suffering from?
  1. Sarcoma
  2. Carcinoma
  3. Lymphoma
  4. Leukemia
  1. Select the correct statement.
  1. Surgery, radiotherapy and chemotherapy can be used to treat lung cancer.
  2. Chemotherapy involves the exposure of cancerous parts to X rays which destroy rapidly growing cancer cells.
  3. Surgical removal of lung cancer tissue is suggested at advanced stage 4.
  4. Monoclonal antibodies can effectively treat lung cancer and can cure it completely.
  1. Assertion: Lung cancer if not treated at an early stage can spread to other initial organs of the body.

Reason: Cancer cell have uncontrolled proliferation and ability to invade new sites (metastasis).

  1. Both assertion and reason are true and reason is the correct explanation of assertion.
  2. Both assertion and reason are true but reason is not the correct explanation of assertion.
  3. Assertion is true but reason is false.
  4. Both assertion and reason are false
→