nucleus function

Flashcards covering nucleus structure, chromosomes, gene versions, transcription/translation, DNA/RNA, mitosis, the cell cycle, and related concepts.

Nucleus

A membrane-bounded organelle that contains a cell's genetic information, bounded by a double membrane, and contains DNA complexed with histones compacted into chromosomes.

Chromosomes (Humans)

Humans have 22 pairs of chromosomes and 1 set of sex-determining chromosomes.

Haploid

Single-celled organisms that carry a single set of chromosomes (e.g., yeast).

Diploid

Multi-cellular organisms that carry two sets of chromosomes.

Polyploidy

Organisms that carry more than two sets of chromosomes.

Homozygous

A gene that is the same on the different copies of the chromosome.

Heterozygous

A gene with different versions on different copies of a chromosome.

Alleles

Different versions of a gene (or DNA locus).

Genotype

Genetic makeup of a cell or organism.

Phenotype

Observable characteristics of a cell, organism, or trait.

Transcription

Process of copying active DNA into RNA in the nucleus.

Translation

Process of converting RNA into protein in the cytoplasm.

Macromolecules (DNA and RNA)

Related molecules where DNA is double-stranded and holds genetic information, and RNA is a single-stranded copy of parts of the DNA.

RNA

A single stranded copy of parts of the DNA. Has a 2’ OH on the ribose ring and contains uracil (instead of thymine).

Genes

DNA that is transcribed (3-4% in humans).

Non-coding DNA functions

Control functions (promoters, enhancers), Structural roles (telomeres, centromeres), and Unknown functions (introns).

rRNA

Ribosomal RNA; plays a structural/functional role in the ribosome.

tRNA

Transfer RNA; brings amino acids to the growing protein chain during translation.

mRNA

Messenger RNA; an intermediate in the flow of information from DNA to protein.

Transcription

Process where mRNA, tRNA, and rRNA are all transcribed from DNA.

Translation (mRNA)

Process where only mRNA is translated into protein.

Mitosis

Replication of chromosomes and division of the nucleus to give two identical daughter nuclei.

Cytokinesis

Division of the cytoplasm into two daughter cells each containing one nucleus.

Cell Replication

Mitosis + Cytokinesis

Sister Chromatids

Copied chromosomes held together at the centromere in metaphase.

Replication Origin (ARS)

Site where DNA replication begins.

Telomere

Protective cap at the end of a chromosome.

Centromere

Region of a chromosome to which microtubules attach during cell division.

Mitosis Stages

Prophase, Metaphase, Anaphase, Telophase

Cyclins

Proteins whose rising and falling levels regulate the stages of the cell cycle.

Cyclin Dependent Kinases (CDKs)

Proteins that phosphorylate cyclins.