Biology Chapter 7 DNA Structure and Replication

DNA

Deoxyribonucleic acid, a complex molecule containing the genetic information that makes up the chromosomes

chromosome

A single, large DNA molecule wrapped around proteins.

located in the nuclei of most eukaryotic cells

double helix

The spiral structure formed by two strands of DNA nucleotides bound together

DNA profile

A visual representation of a person's unique DNA sequence

DNA replication

The natural process by which cells make an identical copy of a DNA molecule

complementary

Fitting together; two strands of DNA are said to be complementary in the A-T & G-C

DNA polymerase

An enzyme that reads the sequence of DNA strand and helps to add complementary nucleotides to form a new strand during DNA replication

semi-conservative

DNA replication is said to be semiconservative because each newly made DNA molecule has one original and one new stand of DNA

PCR

A lab technique used to replicate, and this amplify, a specific DNA segment

genome

One complete set of genetic instructions encoded in the DNA of an organism

STR

Section of a chromosome in which DNA sequences are repeated

gel electrophoresis

A lab technique that separates fragments of DNA by size

nucleotide

Monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

deoxyribose

A five-carbon sugar that is a component of DNA nucleotides

5' carbon

Carbon atom in ribose/dexoxyribose in which the phosphate group is bonded to

1' carbon

Carbon in ribose/deoxyribose in which the nitrogenous base is bonded to

3' carbon

Carbon in ribose/deoxyribose that is bonded to a hydroxyl (-OH) group that DNA polymerase uses to bond a nucleotide to an elongating DNA molecule

antiparallel

The opposite arrangement of the sugar-phosphate backbones in a DNA double helix, subunits run in opposite directions

right-handed helix

Form of most DNA in cells

purines

Nitrogenous bases that have a double ring of carbon and nitrogen atoms such as adenine and guanine

pyrimidines

Nitrogenous bases that have a single ring of carbon and nitrogen atoms, such as cytosine and thymine

Okazaki fragments

DNA fragments that are synthesized in short stretches on the lagging strand

ligase

An enzyme that connects two fragments of DNA to make a single fragment

primer

Short segment of RNA that initiates replication by DNA polymerase

hydrogen bonds

The force of attraction that holds the water molecules together and the separate strands of a DNA double helix together