Question

1.What sequence upstream of AUG in prokaryotic mRNA facilitates recruitment of the 30S ribosomal subunit by base pairing with 16S ribosomal RNA?
A. The Pribnow box
B. The Shine Dalgarno sequence

C. The TATA box

D. The -35 region

E. A stop codon

2.What is the role of the Shine-Delgarno sequence in prokaryotic mRNAs?

1. It specifies the site of translation initiation - ?
2. It specifies the site of polyA addition
3. RNA splicing
4. RNA export
5. It specifies the site of translation termination

3.The molecule below is represented by which abbreviation?

1. AMP
2. ATP
3. GDP
4. UMP
5. GMP

4.The primary structure of a protein specifies

1. its overall three-dimensional structure
2. its linear sequence of amino acids
3. the phi and psi angles for each amino acid
4. the number of each type of amino acid (percent composition)
5. the level of simplicity of the structure

5.Which of the following statements about DNA synthesis in eukaryotes is correct?

1. Synthesis of linear chromosomes leads to telomere shortening in somatic cells
2. Unwinding of DNA by helicases is facilitated by positive supercoils
3. DNA synthesis is initiated at a single origin of replication
4. The daughter strands are synthesised in a 3’-5’ direction
5. Activation of an origin of replication generates a single replication fork

6.The following features are common to all living organisms, except

A.biomolecules.
B. membrane bound organelles
C. RNA molecules

D. DNA sequences

E. metabolic pathways

7.The following features are common to all living organisms, except

A.biomolecules.
B. membrane bound organelles
C. RNA molecules

D. DNA sequences

E. metabolic pathways

8.Vacuoles are important organelles in plant cells that function to

1. fix CO2
2. fix nitrogen
3. regulate osmotic pressure within the cytosol
4. provide energy to plant cells at night
5. provide energy to plant cells in the light

9.Which of the following macromolecules is not found in membranes?

1. Lipids
2. Proteins
3. Carbohydrates
4. Nucleic acids
5. None of the above

10.Cholesterol

1. increases the fluidity of biological membranes
2. decreases the fluidity of biological membranes and hinders transport
3. restricts the movement of phospholipids at 37 °C and impedes solidification at lower temperatures
4. does not play any role in biological membranes
5. none of the above

Answer 1

Q1) In prokaryotes mRNA has a shino-dalgarno sequence upstream of the first codon that forms base pairing with the 16s rRNA of 30S subunit.

Therefore the correct option is option B.

Q2) Shine-Dalgarno sequence in prokaryotic mRNAs serve the main function of binding the mRNA with the ribosome so that the first codon gets properly positioned for initiation of protein synthesis. Therefore the correct option is option A.

Q3) No molecule is provided.

Q4) Primary structure of proteins represents the linear sequence of aminoacids in a polypeptide or protein. The foldings and other complex structures are asociated with the higher order structures like secondary or tertiarry structures. therefore the correct option is option B.

Q5) DNA helicase assisted unwinding of DNA is facililitated by negative supercoiling (which tend to relax te double helix) and there are mutiple origins of replication in eukaryotes that too associated with multiple replication forks. DNA is always synthesized in 5' - 3' direction. However in eukaryotes, there is a replication end problem where the linear DNA is not able to fully synthesize its ends (telomeres) and thus telomere shortening occurs after every replication.

Hence the correct option is option A.

Q6) out of the given options, biomolecules, RNA, DNA and metabolic pathways occur in all organisms, but the membrane bound organelles are present only in eukaryotes and absent in prokaryotes. Therefore the correct option is option B.

Q7) is same to that of Q6.

Q8) Vacuoles are the plant organelles that regulate the osmotic pressue inside the cells to maintian the shape of the cell. Therefore the correct option is option C.

Q9) Out of the given options, lipids, proteins, cholesterol and carbohyrates are present in a cell membrane. However, nucliec acids are not present in membranes.

Therefore the correct response is nucliec acids.

Q10) the correct option is option C.

Cholesterol raises the melting point of biomembranes and thus stabilizes them at high temperatures and at low temperatures, it intercalates between the phospolipids and prevents them from solidification.

Thank you