What determines which genes are expressed in which cells?
Broadly speaking, we can say that a cell’s gene expression pattern is determined by information from both inside and outside the cell. Examples of information from inside the cell: the proteins it inherited from its mother cell, whether its DNA is damaged, and how much ATP it has.
Where are transcription factors located in the cell?
Nuclear localization In eukaryotes, transcription factors (like most proteins) are transcribed in the nucleus but are then translated in the cell’s cytoplasm. Many proteins that are active in the nucleus contain nuclear localization signals that direct them to the nucleus.
How is a gene transcribed?
Transcription is the first step in gene expression. It involves copying a gene’s DNA sequence to make an RNA molecule. Transcription is performed by enzymes called RNA polymerases, which link nucleotides to form an RNA strand (using a DNA strand as a template).
What determines where on the DNA molecule transcription begins and where it ends?
What determines where on the DNA molecule transcription begins and where it ends? Transcription begins at a gene’s promoter, a specific sequence of DNA that acts as a “start” signal for a gene that is to be transcribed. Transcription ends at a sequence of bases that acts as a “stop” signal.
What determines which DNA strand is the template?
The RNA polymerase first attaches to the double helix of DNA and works with proteins called transcription factors to determine what information needs transcribing. The RNA polymerase and transcription factors bind to this DNA strand, called the template strand.
What is the difference between template strand and coding strand?
Template strand contains the same nucleotide sequence as the tRNA. Coding strand contains the complementary nucleotide sequence as the tRNA. Template strand is made up of complementary nucleotide sequence as the mRNA. Coding strand contains the same nucleotide sequence to mRNA, except thymine.
What is template and coding strand?
Hint: The template strand of DNA serves as a template for synthesis of a complementary RNA transcript. The other strand, the coding strand, is similar to the RNA transcript in sequence, besides that it has uracil (U) bases in the region of thymine (T) bases. The coding strand is also said as the sense strand.
Do both strands of DNA code for genes?
Both strands of DNA can encode genes (though the coding sequence of one gene will always be on one strand). Anti-codons refer to segments of tRNA molecules, not parts of a gene.
What is antisense DNA strand?
Antisense is the non-coding DNA strand of a gene. A cell uses antisense DNA strand as a template for producing messenger RNA (mRNA) that directs the synthesis of a protein. These two mRNAs can interact to form a double-stranded structure that cannot be used to direct protein synthesis.
What is a DNA sense strand?
In genetics, a sense strand, or coding strand, is the segment within double-stranded DNA that carries the translatable code in the 5′ to 3′ direction, and which is complementary to the antisense strand of DNA, or template strand, which does not carry the translatable code in the 5′ to 3′ direction.
What are the codes for DNA?
Genetic Code A, C, G, and T are the “letters” of the DNA code; they stand for the chemicals adenine (A), cytosine (C), guanine (G), and thymine (T), respectively, that make up the nucleotide bases of DNA.
Where is your entire DNA code found?
cell nucleus
Why is DNA called the code of life?
DNA is often referred to as the code of life because it is just that: a code containing instructions on how to build various proteins. Other proteins work to protect and maintain the cell’s structure, move cargo around within the cell, or even help cells communicate with and signal to other cells.
What is an example of genetic code?
The genetic code is the set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins (amino acid sequences) by living cells. For example, in humans, protein synthesis in mitochondria relies on a genetic code that varies from the canonical code.
Is gene silencing permanent?
While genome editing technologies, such as CRISPR, “permanently” modify a gene, “temporary” silencing of genes at the mRNA level by siRNAs is desirable in many diseases and would have fewer associated off-target effects. Unlike small-molecule inhibitors or antibodies, siRNAs can act at the specific gene level (3).
What is a silent mutation example?
Silent mutations are base substitutions that result in no change of the amino acid or amino acid functionality when the altered messenger RNA (mRNA) is translated. For example, if the codon AAA is altered to become AAG, the same amino acid – lysine – will be incorporated into the peptide chain.