DNA Structure and Function

Study Notes

Genes are composed of DNA, a chemical that contains genetic material passed down through generations.
DNA is found in the nucleus of almost every cell in the human body, except for red blood cells.

DNA is a unique code that defines every structure and function in an organism, and is passed down from generation to generation.
Each species has its own unique DNA, while individuals within a species have fine variations of the existing DNA.

Ribonucleic acid (RNA): a complementary copy of DNA that carries genetic messages from the nucleus to the cytoplasm.
Karyotype: the arrangement of a complete set of chromosomes in pairs of decreasing size.
Bivalent chromosome: a chromosome with two identical strands, formed during DNA replication, often represented by an 'X' shape.
Chromatid: a single strand of a bivalent chromosome.
Genetic code: the sequence of nucleotides in DNA that is inherited from parents.
Uracil: one of the four nitrogen bases of RNA.
Transcription: the formation of complementary RNA from DNA.

Each cell in the human body (except red blood cells) contains 46 chromosomes, made up of DNA molecules tightly wound around proteins.
Chromosomes are often referred to by numbers according to their size, with the largest pair being number 1.
The last two chromosomes determine the sex of an individual, with human females having two X chromosomes and males having one X and one Y chromosome.
A single chromosome equals a molecule of DNA, and chromosomes can be single or bivalent.

If all the unwound DNA in a single cell were laid out, it would be approximately 2 meters long.

Genes are made of a chemical called DNA, which is the genetic material passed down through generations.
DNA is found in the nucleus of almost every cell in the human body, except for red blood cells.
DNA acts as a blueprint for every structure and function in an organism, containing a unique code that can be passed down to offspring.

Ribonucleic acid (RNA) is a complementary copy of DNA that carries the genetic message from the nucleus to the cytoplasm.
Karyotype refers to the arrangement of a complete set of chromosomes in pairs of decreasing size.
A bivalent chromosome is a pair of identical chromosomes (visualized as an 'X' shape) formed during DNA replication.
A chromatid is a single strand of a bivalent chromosome.
The genetic code refers to the sequence of nucleotides found in DNA that is inherited from parents.
Uracil is one of the four nitrogen bases of RNA.

Each cell in the human body (except red blood cells) contains 46 chromosomes, which are made up of DNA molecules tightly wound around proteins.
Chromosomes are paired and referred to by numbers according to their size, with the largest pair being number 1.
The last two chromosomes determine the sex of an individual, with human females having two X chromosomes and males having one X and one Y chromosome.
A simple equation to understand the relationship between DNA and chromosomes is: A single chromosome = a molecule of DNA.
Chromosomes can be single or bivalent, with each strand of a bivalent chromosome called a chromatid.