Biology Chapter 10 Flashcards

Mutations and Their Effects

• Mutations can create disease-causing alleles or beneficial alleles.
• Some mutations may have no observable effects on the organism.

DNA Replication

• DNA replication occurs rapidly.
• DNA polymerase generates a small number of mistakes during replication.

Heritability of Mutations

• For mutations to be heritable, they must affect egg cells, the gametes passed to the next generation.

Base Pairing Mutation Example

• A specific example of a base pairing mutation is the pairing of G with T.

Transcription Process

• During transcription, an enzyme aligns with DNA to produce RNA from the genetic information.
• This process involves the zipping of enzymes along the DNA strand.

tRNA and mRNA Interaction

• Distinct types of tRNA carry specific amino acids, translating the mRNA message into a sequenced chain of amino acids.

RNA Processing Steps

• RNA processing initiates with the addition of a guanine nucleotide cap.
• Non-coding segments of RNA are removed and remaining segments are spliced together.
• After processing, mRNA, equipped with a cap and tail, exits the nucleus.

Translation Basics

• During translation, mRNA directs the synthesis of proteins in the cytoplasm.
• tRNA transports specific amino acids, while ribosomal subunits assemble to facilitate translation.

Mechanism of Translation

• A second tRNA brings in another amino acid, facilitating bond formation between amino acids through the ribosome.
• The ribosome shifts, resulting in the release of the first tRNA and the introduction of a new tRNA for amino acid addition.

Protein Processing and Transport

• Ribosomes attach to the rough ER for protein growth and processing.
• Newly formed proteins are packaged into vesicles and sent to the Golgi apparatus for further processing.
• Proteins, such as insulin, are eventually secreted from the cell via the plasma membrane.

Key Events in Transcription

• Transcription results in the creation of RNA based on DNA nucleotide sequences.
• During this phase, non-coding segments are removed, and a cap is added to the RNA.

mRNA Characteristics

• Following RNA processing, mRNA travels from the nucleus to the cytoplasm.
• mRNA includes a modified cap but does not directly bind to amino acids during translation.

Site of Translation

• Translation occurs at ribosomes located in the cell cytoplasm, where mRNA is translated into polypeptides.

Role of DNA in Translation

• DNA does not participate in the translation process; its role is strictly to provide the instructions via RNA transcription.

RNA Processing Completion

• mRNA attaching to ribosomes happens after RNA processing, not during the processing phase.

Gene Expression Initiation

• Transcription is the first step in gene expression, converting DNA segments into RNA.

Structure of RNA

• RNA is a linear polymer characterized by a double helix structure found within the nucleus of a cell.