Untitled Flashcards Set

Chargaff's Rules

Purines (Adenine and Guanine) equal Pyrimidines (Thymine and Cytosine); A=T and G≡C.

Rosalind Franklin

Contributed to the understanding of the helical structure and spacing of nitrogenous bases in DNA.

Type of bonds holding DNA strands together

Hydrogen bonds.

Base Pairing of Guanine and Cytosine

Guanine and Cytosine pair with 3 hydrogen bonds.

Base Pairing of Adenine and Thymine

Adenine and Thymine pair with 2 hydrogen bonds.

Euchromatin

A macromolecule that packages DNA in eukaryotes, characterized by loose packing.

Heterochromatin

Tightly packed form of DNA, largely transcriptionally inactive.

Role of DNA

Serves as genetic material in cells.

Nucleosomes

DNA wrapped around a core of histone proteins.

DNA replication method

Semi-conservative, where half of the DNA strand is conserved in each new strand.

Replication origins

Sites where DNA replication begins, leading to formation of replication forks.

Replication forks appearance

Y-shaped junctions formed during DNA replication.

Priming molecule in DNA replication

DNA polymerase.

Role of telomerase

Adds primers to extend DNA strands and completes Okazaki fragments.

Telomeres

Repeated DNA sequences at the ends of chromosomes.

DNA fixing mistakes

Mainly performed by DNA polymerase via proofreading and homologous recombination.

Proteins involved in DNA replication

DNA polymerase (replication and error correction), DNA ligase (seals Okazaki fragments), DNA helicase (unzips DNA), DNA topoisomerases (relieves tension).

Okazaki fragments

Short DNA segments synthesized on the lagging strand during DNA replication.

Differences between RNA and DNA

RNA contains ribose, includes uracil instead of thymine, and is typically single-stranded.

Functional RNAs

Types include mRNAs (code for proteins), rRNAs (form ribosomes), and tRNAs (adaptors during translation).

RNA polymerase

Enzyme responsible for synthesizing RNA from DNA.

Promoter

Region of DNA that initiates transcription.

Terminator

Region of DNA that signals the end of transcription.

Transcription factors

Proteins that bind to specific DNA sequences to regulate transcription.

Eukaryotic mRNA modifications

5' cap and 3' poly A tail.

Introns in eukaryotic RNA

Non-coding sequences spliced out during RNA processing.

Apoptosis

Pre-programmed cell death.

Mitosis phases

Includes prophase, prometaphase, metaphase, anaphase, telophase, and cytokinesis.

Cell cycle control system

System of checks preventing progression to the next stage of the cell cycle when errors occur.

Germ line vs somatic cells

Germ line cells give rise to gametes, while somatic cells maintain the body's functions.

Meiosis phases

Meiosis consists of Meiosis 1 and Meiosis 2, leading to the formation of haploid cells.

Cancer mutations

Result from mutations in proto-oncogenes or tumor suppressor genes.

Mutation types

Include point mutations, deletions, insertions, silent mutations, nonsense mutations, and frameshifts.

DNA repair mechanisms

Include base excision repair, nucleotide excision repair, mismatch repair, and non-homologous end joining.

Junk DNA

Non-coding DNA that has various regulatory roles, despite being labeled as 'junk.'

Transposons

Mobile genetic elements that can change positions within the genome.

Role of intergenic regions

Regulate gene expression and contribute to genomic evolution.