M6 Subtopic 2 Flashcards
DNA stands for
Deoxyribonucleic Acid
molecule that carries the genetic instructions for life
DNA
It is made up of nucleotides (4)
Adenine, Thymine, Cytosine, Guanine
Who first discovered the Double Helix structure?
James Watson and Francis Crick in 1953,
DNA is composed of two long strands that coil around each other to form a ________
Double Helix
Each strand of DNA is made up of repeating units called…?
Nucleotides
Each nucleotide consists of three components:
A phosphate group
A sugar molecule (deoxyribose)
A nitrogenous base
The two strands of the DNA double helix are _____________, meaning the sequence of bases on one strand determines the sequence on the other
Complementary
Pairing of the nucleotides?
Adenine - Thymine / Uracil (RNA)
Cytosine - Guanine
describes the flow of genetic information from DNA to RNA to protein.
central dogma of molecular biology
process by which a cell copies its entire genome before cell division, ensuring that each daughter cell receives an identical set of genetic instructions
DNA replication
Steps of DNA replication, transcription, and translation.
Initiation
Elongation
Termination
begins at specific sites on the DNA molecule called origins of replication. Enzymes like helicase unwind the DNA double helix, creating replication forks
Initiation (replication)
DNA polymerase, the enzyme responsible for synthesizing new DNA strands, adds nucleotides to the exposed DNA template strands in a complementary fashion (A-T, C-G). On the leading strand, DNA is synthesized continuously, while on the lagging strand, it is synthesized in short fragments.
Elongation (replication)
In elongation, on the lagging strand, it is synthesized in short fragments called?
Okazaki fragments
It continues until the entire molecule has been copied. Enzymes like ligase seal the gaps between the Okazaki fragments, creating a continuous strand. The result is two identical DNA molecules, each with one old strand and one newly synthesized strand (semi-conservative replication).
Termination (replication)
the process by which the information encoded in a gene’s DNA sequence is transcribed into messenger RNA (mRNA).
Transcription
Where does transcription take place for eukaryotic and prokaryotic cells?
Nucleus (Eukaryotic)
Cytoplasm (Prokaryotic)
RNA polymerase binds to a specific region of the DNA called the promoter, signaling the start of this process.
Initiation (transcription)
RNA polymerase unzips the DNA and adds complementary RNA nucleotides to form an mRNA strand
Elongation (transcription)
It ends when RNA polymerase reaches a terminator sequence, releasing the newly formed mRNA.
Termination (transcription)
The process by which the genetic code carried by mRNA is decoded by ribosomes to synthesize a specific protein.
Translation
Where does translation occur in both eukaryotic and prokaryotic cells?
Cytoplasm
The ribosome assembles around the mRNA, and the first tRNA (transfer RNA) binds to the start codon (AUG) on the mRNA
Initiation (Translation)
The ribosome moves along the mRNA, reading each codon and bringing in the corresponding tRNA with its attached amino acid. The amino acids are linked together to form a polypeptide chain
Elongation (Translation)
When the ribosome reaches a stop codon (UAA, UAG, or UGA), the translation process ends, and the newly synthesized protein is released.
Termination (Translation)
the process by which the instructions in a gene are used to synthesize a functional product, typically a protein.
Gene expression
Eye color is determined by the amount and type of pigment present in the iris.
What is this pigment called?
Melanin
Types of Mutations
Silent
Missense
Nonsense
Frameshift
These mutations change a nucleotide without altering the amino acid sequence of the protein, usually having no effect on the protein’s function
Silent Mutation
These mutations result in a different amino acid being incorporated into the protein, which may affect the protein’s function, depending on the importance of the altered amino acid.
Missense Mutation
These mutations introduce a premature stop codon, leading to the production of a truncated, usually nonfunctional protein.
Nonsense Mutation
Insertions or deletions that shift the reading frame can result in a completely different and often nonfunctional protein.
Frameshift Mutation
Specific sequences of nucleotides within the DNA that encode instructions for building proteins that carry out most functions in a cell.
Genes
The entire set of genetic material in an organism
Genome
