DNA packaging and RNA Flashcards
What are histones and their role in DNA packaging?
Histones are proteins found in the nucleus. DNA wraps around 8 histone proteins to form a nucleosome, which is the basic unit of chromatin.
What is chromatin?
Chromatin is a chain formed with nucleosomes connected by linker DNA. It packages DNA to fit into the nucleus and regulates gene expression.
How does chromatin become chromosomes?
Chromatin condenses into chromatids, and when the cell is ready to divide, chromatids fully condense to form chromosomes.
What are the types of RNA and their functions?
mRNA (Messenger RNA): Carries genetic instructions from DNA in the nucleus to ribosomes in the cytoplasm.
rRNA (Ribosomal RNA): Combines with proteins to form ribosomes, where protein synthesis occurs.
tRNA (Transfer RNA): Delivers amino acids to ribosomes for protein assembly.
miRNA/siRNA (Micro/Small Interfering RNA): Regulates gene expression by degrading or blocking mRNA.
What happens when DNA is tightly vs. loosely packed?
Tightly packed DNA: Difficult to express genes, often found in inactive regions.
Loosely packed DNA: Easier for gene expression, commonly seen in active regions.
Why is DNA packaging important in cell division?
DNA needs to be packaged into chromosomes to ensure organized and accurate division of genetic material during cell division.
What does the term “unpackaging” mean in gene expression?
Unpacking DNA is necessary for gene expression processes like transcription and replication, allowing genes to be accessible.
