Question

1. By mistake, sterile distilled water is used as an intravenous (IV) solution. The Na+ concentration in water is 0% and the Na+ concentration intracellular (inside the red blood cell) is 0.9%. Is this a problem?

A. No, the sodium ions will diffuse out of the cells, creating equilibrium

B. Yes, the cells will swell and burst

C. No, the cells will remain unchanged

D. Yes, the cells will remain unchanged, but the patient will not receive necessary medications and fluids

2. The genetic information is coded in DNA by:

A. the pattern of sugar and phosphate molecules

B. the sequence of the histone proteins

C. the double helix and its nucleosome pattern

D. the nucleotide sequence

3.Which statement about translation is wrong? (2 points)

A.	Translation is initiated with a start codon and ends with a stop codon

B.	Translation takes place in the cytoplasm at the ribosome

C.	A transfer RNA binds a specific amino acid

D.	The anticodon of the transfer RNA is complementary to the messenger RNA codon

E.	The codons bind to the anticodons forming a polynucleotide molecule

Please show some simple explanation.

Answer 1

1.B.Yes,the cells will swell and burst

Most biological membranes are more permeable to water than to ions or other solutes,and water moves across them by osmosis from a solution of lower solute concentration to one of higher solute conventration.Cell swells when placed in hypotonic solutions.

2.D.The nucleotide sequence

Genetic code is the arrangement of nucleotides in the polynucleotide chain of a chromosome,it governs the transmission of genetic information to proteins.i.e.determines the sequence of amino acids in the polypeptide chain making up each protein synthesized by the cell.Genetic information is coded in DNA by means of four bases:two purines(adenine and guanine)and two pyrimidines (thymine and cytosine).

3.D.The anticodon of the transfer RNA is complementary to the messanger RNA codon

Each anticodon on tRNA matches up with a codon on the mRNA.In this way,amino acids are assembled in the correct order dictated by the mRNA code.The ability of tRNA to match codons with appropriate amino acids is codon recognition.

When the cell is ready to have its genetic code translated into polypeptides,it first has to be prepared with all the essential amino acids.There are 20 different amino acids involved in making proteins.Proteins can only be made correctly when the amino acids are assembled in the right order.The job of tRNA is to match up the amino acids with the correct codons in the mRNA strand.