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Protein synthesis
What is the process of transcription in protein synthesis?
Transcription is the process where DNA is transcribed to produce an mRNA molecule.
Where does transcription occur in the cell?
Transcription occurs in the nucleus of the cell.
What is mRNA?
mRNA, or messenger RNA, is a single-stranded RNA molecule that transfers genetic information from DNA to the cytoplasm.
What enzyme is required for the production of mRNA during transcription?
RNA polymerase.
What happens to the DNA molecule during transcription?
Part of the DNA unwinds and the hydrogen bonds between complementary base pairs break.
What is the template strand of DNA?
The strand of DNA that is transcribed to form the mRNA molecule.
How do free RNA nucleotides pair during transcription?
They pair with exposed complementary bases on the template strand of the DNA.
What happens to the mRNA molecule after it is transcribed?
It leaves the nucleus through a pore in the nuclear envelope.
Why can't DNA travel out of the nucleus?
DNA is too large to fit through the pores in the nuclear envelope.
What mechanism governs gene expression in cells?
Cells can switch certain genes on or off to match requirements; this is called gene expression.
What is the role of ribosomes in translation?
Ribosomes are the site where mRNA is translated into a polypeptide.
What is a codon?
A codon is a sequence of three mRNA bases that corresponds to one amino acid.
What is the role of tRNA in translation?
tRNA brings specific amino acids to the ribosome and pairs with mRNA codons.
What is the significance of stop codons in translation?
Stop codons signal the end of translation, indicating that the polypeptide chain is complete.
What does the genetic code refer to?
The genetic code refers to the sequence of nucleotide bases in DNA that determines the sequence of amino acids in proteins.
How many different amino acids are there that cells use to construct proteins?
There are 20 different amino acids.
What is the term for a change in the sequence of bases in a DNA molecule?
A gene mutation.
What are point mutations?
Point mutations are alterations of a single base in the DNA sequence.
Can mutations occur randomly?
Yes, mutations can occur randomly and are often copying errors that take place during DNA replication.
What is sickle cell disease caused by?
A single point mutation that alters the amino acid sequence in the hemoglobin polypeptide.
What is the genetic code's nature concerning overlaps?
The genetic code is non-overlapping; each base is read only once.
How many different codons can be formed with four nucleotide bases?
64 different codons (4^3 = 64).
Why is the genetic code described as degenerate?
Because multiple codons can code for the same amino acid.
What is the primary location for translation in the cell?
Translation occurs in the cytoplasm.
What happens to the polypeptide chain during translation?
It elongates as tRNA molecules bring amino acids to the ribosome.
What type of bond forms between amino acids during synthesis of a polypeptide?
A peptide bond.
What is the energy source for the translation process?
ATP,
In which cellular process are amino acids covalently bonded together?
Translation.
What is the analogy used for understanding transcription and translation?
Transcription and translation are likened to converting between languages.
What ensures that DNA and RNA have complementary sequences?
Complementary base pairing rules.
Which nucleotide in RNA replaces thymine from DNA?
Uracil (U).
What does the process of transcription entail?
Conversion of DNA sequence into an mRNA sequence.
How does the ribosome function during translation?
The ribosome moves along the mRNA, facilitating the binding of tRNA to codons.
What is the implication of the mutation in sickle cell disease?
The mutation leads to the production of abnormal hemoglobin, causing red blood cells to become sickle-shaped.
What can happen in the cell due to mutations in gametes?
They can lead to heritable genetic conditions.
How are mRNA codons determined?
They are determined by the template strand's DNA sequence.
What does the term 'messenger' refer to in mRNA?
It carries genetic messages from the DNA to the cytoplasm.
What is the basic structure of rRNA?
rRNA is a component of ribosomes, formed by a large and small subunit.
What are the functions of amino acids in metabolism?
They participate in the building of proteins, which are essential for various cellular functions.
What is an example of a start codon?
AUG, which codes for methionine.
What role does each triplet of bases on a DNA strand play?
Each triplet codes for a specific amino acid.
What happens during the elongation phase of translation?
tRNA molecules bring amino acids together and form peptide bonds.
Where do the steps of protein synthesis occur?
Transcription occurs in the nucleus and translation occurs in the cytoplasm.
Identify the two main types of mutations.
Point mutations and frameshift mutations.
What occurs if a mutation takes place in a normal somatic cell?
It is generally not inherited by offspring.
Which genetic disorder is the result of a single point mutation in hemoglobin?
Sickle cell disease.
What is the outcome of the sickle cell mutation in hemoglobin's structure?
It modifies the shape and function of red blood cells.
Why are some mutations considered beneficial?
They can provide an advantage in survival or reproduction.
What is included in the definition of a codon?
A codon consists of three consecutive bases on mRNA.
Who articulated the universal nature of the genetic code?
It signifies that nearly all organisms employ the same genetic code.
What is one key feature of the genetic code?
It is degenerate, meaning multiple codons can specify the same amino acid.
What change occurs due to mutations on the DNA level?
They can lead to changes in the sequence of amino acids in proteins.
Why can mutations in gametes be inherited?
They can be passed to offspring during reproduction.
How do mutations influence evolutionary processes?
They generate genetic variation, which can be acted upon by natural selection.
What must occur when the ribosome reaches a stop codon?
Translation ceases, and the newly formed polypeptide is released.
What does the stability of DNA imply about gene expression?
It enables reliable templates for transcription across generations.
What is a key difference between DNA and RNA?
RNA contains uracil instead of thymine.
What can point mutations lead to in a hemoglobin molecule?
They can alter the properties and functionality of hemoglobin, as seen in sickle cell disease.
Why are mutations important to genetic engineering?
They facilitate the transfer of genes between species due to the universal genetic code.
During which phase does DNA replication occur prior to transcription?
S phase of interphase.
What can be an effect of sickle cell anemia on the human body?
It can cause pain, fatigue, and reduced oxygen delivery to tissues.
What does ATP provide during the translation process?
The energy required for peptide bond formation.
What does the term 'universal' signify in relation to the genetic code?
It indicates that the same triplet codes for the same amino acids across different organisms.
