DNA Structure, Replication, and Gene Expression

Flashcards about the structure of DNA and gene expression

Levene

Identified the structure of the four nucleotides in DNA

Griffith

Discovered transformation; genetic material can be transferred between bacteria, foundation of heredity

Hershey & Chase

Discovered that DNA is the genetic material

Chargaff

Established base-pairing rules: A=T, C=G

Franklin & Wilkins

Produced the 1st x-ray diffraction image of DNA, providing insight into its structure

Watson & Crick

Correctly predicted the structure of DNA, earning a Nobel Prize

Function of DNA

To store genetic information

Structure of DNA

Composed of nucleotides, complementary strands, anti-parallel backbones, purines, pyrimidines, hydrogen bonds, and follows base-pairing rules

Nucleotides

The three parts are: phosphate, ribose sugar, and nitrogen base

Variable part of a nucleotide

Nitrogen base

Constant part of a nucleotide

Phosphate and ribose sugar

Complementary DNA strands

One strand matches the other, fitting together like hands

Anti-parallel DNA

The backbones are parallel but run in opposite directions

DNA backbone

Outside regions of the molecule composed of repeating phosphate groups and 5-carbon sugars

Purines

Category of nucleotide with 2-ringed nitrogenous bases A & G

Pyrimidines

Category of nucleotide with 1-ring nitrogenous bases: T, C, & U

Hydrogen Bonds in DNA

Weak bonds that hold the two strands of DNA together between the nitrogen bases

Base-pairing rules

Adenine double bonds with Thymine, Cytosine triple bonds with Guanine

Central Dogma of Biology

DNA → mRNA → protein; the universal principle that applies to biology and gene expression

Double Helix

Two strands of nucleotides twisted around each other

Nucleotides

Subunits that make up DNA

Deoxyribose

A five-carbon sugar

Hydrogen Bond

Type of weak bond between base pairs that holds the double helix together

Nitrogenous Bases

Four kinds - Adenine, Thymine, Cytosine, Guanine - that form specific pairs

Adenine

One of two purines used as a nitrogenous base in nucleotides

Cytosine

One of two pyrimidines used as a nitrogenous base in nucleotides

Chargaff

Discovered that the amount of adenine always equals the amount of thymine and that guanine always equals cytosine

Ribonucleic acid (RNA)

A molecule made of linked nucleotides

Uracil

A nitrogenous base used in RNA instead of the base thymine found in DNA

Transcription

The process of transferring a gene's instructions for making a protein to an RNA molecule

Translation

The process of reading instructions on an RNA molecule to put together the amino acids that make up a protein

Gene Expression

The entire process by which genes are used to build proteins/traits

Codon

A 3-nucleotide sequence of mRNA

RNA polymerase

Reads DNA & makes mRNA

mRNA

RNA transcript of the gene in DNA, carries the gene recipe to the cytoplasm

tRNA

Link between genetic material (RNA) and amino acids, carries amino acid corresponding to the codon

rRNA

Structural component (along with protein) of ribosomes