Biology

Codon

A codon is a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis.

Tetrads

A four-part structure that forms during prophase I of meiosis and consists of two homologous chromosomes, each composed of two identical chromatids.

Autosomes

An autosome is a chromosome that is not an allosome (i.e., not a sex chromosome). Autosomes appear in pairs whose members have the same form but differ from other pairs in a diploid cell, whereas members of an allosome pair may differ from one another and thereby determine sex.

Chromosomes

Chromosomes are the things that make organisms what they are. They carry all of the information used to help a cell grow, thrive, and reproduce. Chromosomes are made up of DNA. Segments of DNA in specific patterns are called genes.

Diploid cell & haploid cell

Diploid cells have two homologous copies of each chromosome.Haploid describes a cell that contains a single set of chromosomes.

Chromatids

Either of the two strands formed when a chromosome duplicates itself as part of the early stages of cell division. The chromatids are joined together by a single centromere and later separate to become individual chromosomes

Helicase

Helicases are enzymes that bind and may even remodel nucleic acid or nucleic acid protein complexes. There are DNA and RNA helicases.

Histones & non- histones

Histones help maintain the shape of DNA and they aid in a tight packing. Non-histones are proteins that controls the spots on the DNA.

Karyotypes

Most living things have chromosomes, or units of genetic information, in their cells. The number and appearance of chromosomes vary among species. A karyotype is the number, size, and shape of chromosomes in an organism.

Binary Fission

Prokaryotic fission, which is binary fission, is a form of asexual reproduction and cell division used by all prokaryotes.

Purine and pyrimidines

Purine is a substituted derivative of this, especially the bases adenine and guanine present in DNA and RNA. A pyrimidine is while both of the purines (adenine and guanine) are present in RNA and DNA, the pyrimidine composition of RNA and DNA differs slightly. Cytosine is present in both RNA and DNA. However, whereas DNA contains thymine, RNA contains uracil.

Homologous chromosomes

The 22 pairs of homologous chromosomes contain the same genes but code for different traits in their allelic forms since one was inherited from the mother and one from the father. So humans have two homologous chromosome sets in each cells, meaning humans are diploid organisms.

Centromere

The centromere is the part of a chromosome that links sister chromatids. During mitosis, spindle fibers attach to the centromere via the kinetochore.

Cytokinesis- Cleavage furrow/cell plate

The division of the cytoplasm and the plasma membrane following the division of the nucleus resulting into two cells, each having its own nucleus and cytoplasm surrounded by a plasma membrane.

Sex chromosomes

a chromosome, differing in shape or function from other chromosomes, that determines the sex of an individual.

Nucleic acids

a complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain.

Nucleotides

a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.

Nitrogen containing bases

a nitrogen-containing organic compound that has the chemical properties of a base, especially a pyrimidine or purine.

Anticodon

a sequence of three nucleotides in a region of transfer RNA that recognizes a complementary coding triplet of nucleotides in messenger RNA during translation by the ribosomes in protein biosynthesis.

Spindle Fibers- kinetochore & polar fibers

a spindle-shaped structure, composed of microtubules, that forms near the cell nucleus during mitosis or meiosis and, as it divides, draws the chromosomes to opposite poles of the cell. large multiprotein complexes that bind the centromeres of the chromosomes to the microtubules of the mitotic spindle during metaphase in the cell cycle. Polar fibers are Chromosomes are attached to kinetochore microtubules via a multiprotein complex called the kinetochore. Polar microtubules interdigitate at the spindle midzone and push the spindle poles apart via motor proteins. Astral microtubules anchor the spindle poles to the cell membrane.