DNA Structure and Replication

Flashcards covering key vocabulary and concepts related to scientists, DNA structure, and DNA replication.

Frederick Griffith

The first to identify or discover the bacterial transformation

Oswald Avery

discovered that DNA stores and transmits genetic information from one generation of bacteria to the next

Alfred Hershey and Martha Chase

This scientist pair confirmed Avery’s results, convincing many scientists that DNA was the genetic material found in genes, not just viruses and bacteria, but in all living cells

Erwin Chargaff

He discovered that the base pairs A and T are equal to each other, and so are C and G; this is also called Chargaff’s rule

Rosalind Franklin

Her X-ray pattern does not reveal the structure of DNA, but it carries some crucial clues

Maurice Wilkins

He uncovered the structure of DNA; he was involved by giving X-ray diffraction and showing the first crystalline symmetrical patterns of DNA

Watson and Crick

Wilkins help to guide this pair to build a model that explained the specific structure and properties of DNA; they discovered the double helix in 1953

DNA

Deoxyribonucleic Acid

Monomer

A building block molecule that can link with other molecules to form a larger molecule; an example would be the nucleotides because they form DNA and RNA; protein building blocks are amino acids

Parts of a Nucleotide

Phosphate, Carbon Sugar (Deoxyribose), and a Nitrogen Base

Pentose Sugar

Either Deoxyribose or Ribose

Types of Nitrogenous Bases

Adenine, Thymine, Cytosine, Guanine

Purines

2 rings of carbon and nitrogen atoms; Adenine and Guanine

Pyrimidines

1 ring of carbon and nitrogen atoms; Thymine/ Uracil and Cytosine

Base Pair Rule

Adenine can bond only with Thymine (A-T or T-A - 2 Hydrogen bonds); Cytosine can only bond with Guanine (C-G or G-C - 3 Hydrogen bonds)

Unwind (DNA Replication)

Topoisomerase unwinds the coiled strands of DNA

Unzip (DNA Replication)

DNA Helicase “unzips” the strands of DNA, breaking the hydrogen bonds, creating two template (parent) strands for replication

Hold Open (DNA Replication)

Single-strand binding proteins (SSBs) keep strands separated

Base Pairing (DNA Replication)

DNA Polymerase III bonds free nucleotides with complementary nucleotides on each template (parent) strand using base pairing rules

Proofread (DNA Replication)

DNA polymerase I proofreads new strands and backtracks to correct errors

Joining Nucleotides (DNA Replication)

DNA ligase bonds the backbone together

Enzyme

a type of protein that helps to speed up chemical reactions

Topoisomerase

an enzyme that helps to unwind the DNA double helix in DNA replication

Helicase

an enzyme that helps to unzip the DNA strands to prepare them for the addition of nitrogenous bases

Ligase

an enzyme that seals the Okasaki fragments together to make the DNA strand seamless

Bacteriophage

A type of virus that infects and destroys bacteria; it looks a bit like a robot and uses its tail to inject its DNA into a bacterial cell

SSB proteins

These proteins attach to single strands of DNA during copying (replication) to keep them from folding or sticking back together before they are copied

DNA Primase

This is an enzyme that makes a short piece of RNA called a primer; the primer helps the main copying enzyme know where to start building the new DNA strand

DNA Polymerase III

This enzyme adds new DNA pieces to the strand being copied; it works quickly and is the main enzyme that copies most of the DNA

DNA Polymerase I

This enzyme comes in after DNA Polymerase III; it removes the RNA primers and replaces them with real DNA pieces