BIO- UNIT 3 Flashcards
what are the applications of PCR and gel electrophoresis?
DNA profiling. PCR is used to make more copies of the specific DNA. Gel electrophoresis is used to determine whether the samples of DNA are from the same host by experimenting.
are all genes synthesized continuously?
Some genes are transcripted continuously, meaning that it happens all the time as cells need than all the time.
One example is ATP synthase. Since all cells need energy all the time, the. the body needs to keep forming ATP synthase.
Some genes do not need transcription all the time. One example is insulin. The body does not need to regulate blood glucose levels all the time, only when it is too low or too high.
what is gene expression?
Gene expression is where information carried by a gene leads to observable traits (phenotypes) for an organism.
does base sequence determine the observable traits of an organism?
no. This is because observable traits are determined by the sequences of amino acids in a particular polypeptide.
what does the mRNA do and what does it make?
mRNA carries genetic information from the DNA that is synthesized through transcription into RNA. Afterwards, the mRNA is sent to the ribosome. Then, through translation, it forms amino acids that form proteins.
what are genes?
a segment of DNA that contains the instructions for the synthesis of RNA molecules and proteins.
what is coding DNA?
When a segment of DNA is transcribed into RNA and then translated into proteins or polypeptides
what is non-coding DNA?
A section of the DNA that does not code for proteins.
some examples:
introns- do not carry instructions for protein synthesis, therefore need to be removed before the final maturation of mRNA
telomeres- structures that form at the end of chromosomes
base sequences used in the regulation of gene expression (promoters, enhancers, silencers)
rRNA
tRNA
what are exons?
Opposite of introns, they carry instructions for protein synthesis (translation in the ribosome)
exons- express instructions for protein synthesis
introns- interrupt the process (must be removed)
What is post-transcriptional modification? What are the post-transcriptional modifications for the RNA?
Modifications are made after DNA transcribes into primary RNA. Primary RNA (before moving out of the nucleus) needs to mature into mature mRNA before moving through the cytoplasm and into the ribosome.
Examples:
five prime caps are formed at the 5’ end
poly (A) tails are formed at the 3’ end
introns are removed through RNA splicing
Describe RNA splicing, five prime caps synthesis, and Poly-A tails synthesis.
- introns are removed from the primary RNA by enzymes called spliceosomes, as they cannot create a protein with the right sequence.
- Five-prime caps are formed: creates a specialized cap at the 5’, and a tail at 3’. At the 5’ end, a modified nucleotide is added as a cap (it prevents the degradation of mRNA and gives the starting point of translation at the ribosomes).
- Poly (A) Tails are formed at the 3’ end: between 100 to 200 adenine nucleotides are added at the tail. Also prevents degradation and makes mRNA more stable
what is the strand of DNA where RNA polymerase travels on to form RNA called?
the template strand or antisense strand.
explain transcription
- RNA polymerase begins its journey at the promoter sequence by binding to the DNA at this region.
- RNA polymerase reads the DNA template strand (anti-sense strand)- where the addition of RNA nucleotides occurs, in the 3’ to 5’ direction and adds 5’ to 3’.
- RNA polymerase adds bases based on the complementary base pairing (A and U, C and G)
- After the RNA polymerase reaches the terminator region, the RNA polymerase is detached from the template (anti-sense) strand. The addition of RNA nucleotides is stopped, and transcription ends.
- primary RNA is synthesized
Describe the condensation reaction in saccharides.
When saccharides combine to form disaccharides and polysaccharides, a condensation reaction occurs. An H2O molecule leaves as the saccharides form a glycosidic bond,
what is mRNA, tRNA, and rRNA?
mRNA: messenger RNA that carries the information needed for protein synthesis to the ribosome. travels from the nucleus through the cytoplasm and into the ribosome
tRNA: transfer RNA, non-coding DNA, located in the cytoplasm, adds amino acids to the growing chain that eventually becomes protein or polypeptides.
rRNA: ribosomal RNA combines with ribosomal proteins to synthesize cytoplasmic ribosomes
what is RNA splicing?
RNA splicing is where the primary RNA’s introns are removed by the spliceosomes. Only the exons will remain afterward.
what is a codon?
A codon is a sequence of 3 consecutive nucleotides that codes for a specific amino acid.
what is an anti-codon?
An anti-codon is a sequence of 3 consecutive nucleotides on a tRNA that attaches to the complementary codons of the mRNA during protein synthesis.
