Biology Unit 7

Mitosis

A process of cell division where one cell divides to produce two identical daughter cells, ensuring equal genetic material distribution.

Binary Fission

A simple form of asexual reproduction common in prokaryotes where a single cell divides into two, without the formation of mitotic spindles.

Somatic Cells

All body cells produced from a zygote, except for reproductive cells, undergo mitosis for growth and repair.

Zygote

The fertilized egg cell that undergoes mitosis to develop into a multicellular organism.

Plasmid

A small, circular, double-stranded DNA molecule distinct from chromosomal DNA, often carrying genes that confer survival advantages to bacteria.

Chromatin

The complex of DNA and proteins in eukaryotic cells that condenses to form chromosomes during cell division.

Okazaki Fragments

Short, newly synthesized DNA fragments formed on the lagging strand during DNA replication.

Transcription

The process by which the information in a gene is used to synthesize RNA.

Translation

The process of converting the mRNA sequence into a polypeptide chain (protein) at the ribosome.

Codon

A three-nucleotide sequence on mRNA that specifies an amino acid.

Anticodon

A three-nucleotide sequence on tRNA that is complementary to an mRNA codon.

Promoter

A specific DNA sequence where RNA polymerase binds to initiate transcription.

Intron

Non-coding sequences in a gene that are removed during RNA splicing.

Exon

Coding sequences in a gene that are retained after RNA splicing and expressed as proteins.

Chargaff's Rule

In any double-stranded DNA, the amount of adenine (A) equals thymine (T), and the amount of cytosine (C) equals guanine (G).

Frameshift Mutation

A genetic mutation caused by insertions or deletions that shifts the reading frame of the genetic message.

Aneuploidy

An abnormal number of chromosomes in a cell, often resulting from nondisjunction during cell division.

Transposon

A DNA sequence that can change its position within the genome, potentially causing mutations.

Lytic Cycle

The viral reproductive cycle in which the virus takes over the host cell's machinery to replicate and ultimately causes cell lysis.

Lysogenic Cycle

The viral reproductive cycle where the viral DNA integrates into the host's genome and replicates along with it without destroying the host.

Ribozyme

A type of RNA molecule that can act as an enzyme to catalyze biochemical reactions.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during cell division.

Central Dogma of Molecular Biology

The framework describing the flow of genetic information from DNA to RNA to protein.