Biology slides 10
What is the structure of DNA?
DNA is a double-stranded polymer of nucleotides held together with hydrogen bonds.
What is a chromosome?
A chromosome is a double-stranded DNA molecule that contains coding and noncoding DNA.
What is the collection of all chromosomes in an organism called?
The genome.
What proteins do DNA molecules wrap around?
Positively-charged histone proteins.
What is chromatin?
The hierarchical organization of DNA wrapped around histone proteins.
What are the two types of nucleic acids?
DNA and RNA.
How does DNA pair its nucleotides?
A pairs with T, and C pairs with G.
What is the role of RNA?
RNA serves as a short-term storage and working copy derived from DNA.
What is the Central Dogma of Molecular Biology?
The process by which DNA is transcribed into RNA, which is then translated into protein.
What is transcription?
The process of copying a gene from DNA to produce messenger RNA (mRNA).
What is the role of RNA Polymerase?
RNA Polymerase forms phosphodiester bonds between RNA nucleotides during transcription.
What happens during the elongation phase of transcription?
RNA Polymerase moves along the template strand, synthesizing mRNA in the 5'-3' direction.
What is the PolyA Signal?
A specific sequence that signals the end of transcription in eukaryotes.
What modifications does mRNA undergo before leaving the nucleus?
mRNA undergoes capping, polyadenylation, and splicing.
What is translation?
The process of using mRNA to synthesize proteins with the help of ribosomes and tRNA.
What are codons?
Codons are sequences of three nucleotides in mRNA that correspond to specific amino acids.
How many possible codons are there?
There are 64 possible codons derived from four nucleotides.
What is the genetic code?
The genetic code is a set of rules that defines how nucleotide sequences are translated into amino acids.
What is the significance of gene expression?
Gene expression allows cells to use specific genes, giving them distinct structures and functions.
What are transcription factors?
Proteins that attach to specific DNA sequences to regulate the start of transcription.
What is the template strand in transcription?
The strand of DNA that RNA Polymerase uses as a guide to sythesize mRNA.
What happens to the DNA strands during transcription?
The two strands of DNA separate, and the template strand is used to synthesize mRNA.
What is the direction of RNA synthesis?
RNA is synthesized in the 5' to 3' direction.
What happens to RNA Polymerase after it trascribes the PolyA Signal?
RNA Polymerase detaches from the gene, completing transcription.
What is the role of tRNA in translation?
tRNA molecules read mRNA codons and bring the corresponding amino acids to the ribosome.
What is the function of the ribosome during translation?
The ribosome facilitates the binding of tRNA to mRNA and catalyzes the formation of peptide bonds between amino acids.
What initiates the translation process?
Translation begins when the ribosome attaches to the 5' end of mRNA and locates the first AUG codon.
What is the first amino acid incorporated into a newly synthesized protein?
Methionine (Met) is always the first amino acid in a newly-made protein.
What happens when the ribosome encounters a stop codon?
A release factor protein is recruited, causing the ribosome to disassemble and release the newly synthesized polypeptide.
What are untranslated regions (UTRs) in mRNA?
UTRs are portions of mRNA that come before or after the coding region and are not translated into protein.
What is a mutation?
A mutation is a change in the nucleotide sequence of DNA, which can affect the protein produced.
What are the types of gene mutations?
Gene mutations can be substitutions (silent, missense, nonsense) or insertions/deletions that can cause frameshifts.
What is a silent mutation?
A silent mutation is a substitution that does not change the amino acid sequence of the protein.
What is a missense mutation?
A missense mutation is a substitution that results in a different amino acid being incorporated into the protein.
What is a nonsense mutation?
A nonsense mutation is a substitution that creates a stop codon, prematurely terminating protein synthesis.
What is a frameshift mutation?
A frameshift mutation occurs when nucleotides are inserted or deleted, altering the reading frame of the mRNA.
How does the ribosome read the mRNA?
The ribosome reads codons sequentially and not in an overlapping manner, maintaining a specific reading frame.
What is the significance of the AUG codon?
The AUG codon serves as the start codon for translation, signaling the beginning of protein synthesis.
What is the role of the release factor in translation termination?
The release factor binds to the stop codon in the A site, triggering the disassembly of the ribosome and release of the polypeptide.
How many different proteins can be produced from approximately 22,000 genes?
There are over 1,000,000 different proteins in the body due to post-translational modifications and variations in protein synthesis.
What is the coding region of mRNA?
The coding region of mRNA is the part that is translated into a protein, starting at the AUG codon and ending at a stop codon.
What are the components of the ribosome?
The ribosome is composed of proteins and ribosomal RNA (rRNA).
What does the term 'wild type' refer to in genetics?
Wild type refers to the typical form of a gene or organism as it occurs in nature, without mutations.
What is the significance of the 5' and 3' ends of mRNA?
Translation begins at the 5' end and ends at a stop codon, not at the absolute 3' end of the mRNA.
What is the function of the anticodon in tRNA?
The anticodon in tRNA pairs with the corresponding codon on mRNA during translation.
What is the role of GTP in translation termination?
GTP hydrolysis provides energy for the disassembly of the ribosomal subunits and mRNA after translation.
What happens to tRNA after it has delivered its amino acid?
The tRNA is released from the ribosome after the amino acid has been added to the growing polypeptide chain.
What is the impact of insertions or deletions in the coding region?
Insertions or deletions can lead to frameshift mutations, altering the entire downstream amino acid sequence.