DNA Structure & DNA Fingerprinting

Flashcards covering DNA structure, replication, chromosomal organization, and DNA fingerprinting techniques based on lecture notes.

DNA

The genetic material found in all living organisms, characterized by a double helix (twisted ladder) structure.

X-Ray Crystallography

The technique used by Rosalind Franklin and Maurice Wilkins in 1952 to demonstrate that DNA had a helical shape.

Prokaryotic DNA Location

DNA situated directly in the cytoplasm of the cell.

Eukaryotic DNA Location

DNA located in the nucleus, separated from the rest of the cell by a nuclear envelope.

Nucleotide

The building block of DNA consisting of three parts: a phosphate, a sugar, and a base.

DNA Bases

The four types of bases in DNA: Adenine, Guanine, Cytosine, and Thymine.

Complementary Base Pairing

$A-T$ pairs together and $C-G$ pairs together.

Sugar-Phosphate Backbone

The structural framework of DNA to which the four bases are bound.

Antiparallel

The directionality of DNA where each strand is in the opposite direction and they meet in the middle.

Chromatin

The uncondensed form of DNA and protein, often described as “noodles,” available for protein synthesis in the nucleus.

Chromosomes

Tightly wound DNA and protein carrying gene info that form after replication in interphase to prepare for cell division.

Homologous pairs

A pair of related chromosomes where one copy is from the mother and one copy is from the father; humans have 23 pairs.

Diploid ($2n$)

An organism or cell containing two sets of chromosomes, which characterizes human body cells.

Haploid ($1n$)

An organism or cell containing one set of chromosomes, such as human gametes (sperm and egg cells).

DNA Helicase

The enzyme that “unzips” the DNA strand during replication.

Semi-conservative replication

The process of DNA replication where each side of the original strand serves as a template, resulting in a new strand that is half new and half old.

DNA Fingerprinting (RFLP)

Also known as Restriction Fragment Length Polymorphism, it involves analyzing DNA fragments from different people to look for matches using gel electrophoresis.

Restriction Enzymes

Re-usable tools that make specific cuts in DNA, such as EcoRI, BamHI, and HindIII.

Sticky ends

DNA fragments with unpaired bases at the ends, produced by restriction enzymes like BamHI, HindIII, and EcoRI.

Blunt ends

DNA fragments produced by restriction enzymes like Alul and Haelll that do not have unpaired bases.

Gel Electrophoresis

A method to separate DNA fragments on an agarose gel where size/length determines distance; small pieces run farther than large pieces.

Micropipette First Stop

The position of the micropipette plunger used for drawing liquid into the tip.

Micropipette Second Stop

The position of the micropipette plunger pressed all the way down to push liquid out.