Question

(a) Describe LINES and SINES.

(b) State the genetic and protein components needed for efficient transcription of a gene, and their roles.

(c) Explain the process whereby a nuclear-encoded protein is transported into the chloroplast.

(d) Explain the process of protein folding.

Answer 1

a, Answer:

SINEs are short interspersed nuclear elements, that invade new genomic sites using RNA intermediates. , the transposable elements (TEs) ranging from 100 to 700 base pairs in length, they are class of retro-transposons. SINEs are almost found in all eukaryotes except in Saccharomyces cerevisiae) for at least 34% of the human genome. Non-coding SINEs depends on reverse transcriptase.

LINEs are long interspersed nuclear elements are defined as those elements that essentially encode all the sequences that enable them to move. These insert themselves into regions of the eukaryotic genome that are rich in bases (AT). At (AT) regions this uses its nuclease to cut one strand of the eukaryotic double-stranded DNA by recognizing these hydroxyl groups in Reverse transcriptase and synthesize LINE retro-transposon, where the DNA is cut.

b. Answer: Genetic and protein needed for efficient transcription are:

Enzymes are known to be RNA polymerases build RNA molecules that are complementary to a portion of one strand of the DNA double helix.

RNA molecules are important in many ways during transcription.

These are single stranded and fold into complex structures which are stabilized by internal complementary base-pairing.

These are having a ribose sugar, uracil (U) nucleotides. These are involved in expression of gene coding with in a cell’s DNA. The three molecules are also involved are as follows:

Messenger RNA (mRNA) molecules: These transfer the coding sequences for protein synthesis and are referred as transcripts.

Ribosomal RNA (rRNA) molecules:

These form the core of a cell's ribosome’s where protein synthesis takes place. Transfer RNA (tRNA) molecules: These transfer amino acids to the ribosome’s during protein synthesis.

Cells can be analyzed by the spectrum of mRNA molecules present with-in them; The formed spectrum is called the transcriptome. Whereas each cell in a multicellular organism can carry the same DNA or genome, then its tran-scriptome varies widely according to cell type and its function.

For example, the insulin-producing cells of the pancreas contain transcripts for insulin, but bone cells do not. Therefore bone cells carry the gene for insulin, this gene is not transcribed. Thus, the transcriptome functions may play an important role and as acts catalog of all of the genes that are being expressed in a cell at a particular point in time.

C. Answer:

The proteins in chloroplasts are being encoded by the nuclear genome and synthesized as precursors with N-terminal targets signaling called Transit peptides. The specific import these proteins from the cytosol into chloroplasts. This specific novel method consists of more than a 12 components located inside and around the chloroplast coverage. This includes a pair of GTP-ase receptors, a beta-barrel-type channel across the outer membrane & AAA +/- type motor in the stroma.

The assemblage of individual components into functional sub-complexes and the steps involved in the translocation process are being mapped out. These pathways occurred with initial transport through the endo-membrane system.

There by Protein transport into chloroplasts occurs in a controlled multiple levels have been evolved, it also includes development of two receptor subfamilies, one is for photosynthetic proteins and other is for housekeeping proteins. The expressions (or) function levels of some translocon components are further adjusted according to plastid type used, during developmental stage, and metabolic conditions.

D. Answer: Protein folding process:

In this, protein structure assumes its functional shape or conformation. These molecules are heterogeneous, un-branched chains of amino acids. These molecules by coiling and folding into a specific three-dimensional (3D) shape and perform their biological function.

There are 4 stages of protein folding process:

Primary: Referred to as linear sequence of amino-acid residues in the polypeptide chain.

Secondary: These are developed by formation of hydrogen bonds between atoms in the polypeptide backbone, which folds the chains into either alpha helix (or) beta-sheets.

Tertiary: These are being formed by the folding of the secondary structure sheets (or) helix into one another. This has geometric shape of the protein. These are determined by the interactions and bonding of the amino acid side chains present in the protein.

Quaternary: This structure is formed by folded amino-acid chains in tertiary structures interacting further with each other to give rise to a functional protein like hemoglobin (or) DNA polymerase.

Note: The provided answer is as per my knowledge may be or may not be 100% correct, but definitely relevant to your question thank you so much.