Bases of Life

Double Helix

The form of native DNA referring to its two adjacent polynucleotide strands intertwined into a special shape

Each nucleotide base has

Protruding functional groups (purine/pyrimidine complements) that form hydrogen bonds with their appropriate partner

C-G base pair has functional groups that form

3 hydrogen bonds

A-T base pair has functional groups that form

2 hydrogen bonds

The two things that make up chromosomes

Protein and DNA

DNA has 4 ________, while ________ has 20 different _______

Nucleotides, protein, R-groups

What virus did the Hershey and Chase Blender Experiments use on the bacteria? What two things did the virus contain? What bacteria was affected by the virus?

Bacteriaphage; Protein and DNA; E. Coli

Why was the Hershey and Chase experiment called the Blender Experiment?

Because they put everything in a blender to mix the E. Coli and Bacteriaphage all together

What was the Centrifuge used in the Blender Experiment for?

To separate the part of the virus that got knocked off from the rest of the virus

What parts of the Bacteriaphage got knocked off?

The protein coat

What did they use to label the different parts of the bacteria? Which label got which each part?

They used radioactive isotopes of phosphorus and sulfur; ³²P goes with Phosphorus as the radioactive isotopes for DNA, and ³⁵S goes with Sulfur as the radioactive isotopes for Protein

What is the supernatent and the bacterial pellet?

The Supernatant is the part of the centrifuge containing the protein coats, while the bacterial pellet contained the E. Coli and the DNA from the Virus

What did Whatson and Crick predict? How did their model show this?

They predicted that the specific pairing of complementary bases accounts for the ability of DNA to be copied; Their model showed that when a double helix replicates, each of the two daughter molecules will have one old strand from the parental molecule and one newly created strand

Replications of a chromosomal DNA

begins at particulate sites called origins of replication, short stretches of DNA having a specific sequence of nucleotides

The sugar’s ________ atom is attached to an _______ group at one end of the DNA strand; at the other end, that sugar’s _______ carbon is attached to a _______ group

3; —OH; 5; phosphate

The enzymes that link DNA molecules to a growing daughter strand are called

DNA polymerases

What are Okazaki fragments? What are they linked together by?

the short pieces of the Daughter DNA strand made by DNA polymerase working outward from the forking point is parental DNA; DNA ligase

An organism genotype is

The heritable information contained in the sequence of nucleotide bases in DNA.

A gene

Dispatches instructions in the form of RNA, which in turn programs protein synthesis

Two main stages

Transcription and Translation

Transcription vs Translation

The nucleic acid language of DNA has been rewritten as a sequence of bases of RNA in transcription, while in translation, there is a change in language from the nucleotide sequence of the RNA to the amino acid sequence of the polypeptide.

Triplet Code

A set of 3-nucleotide long “words” specifying the amino acids for polypeptide chains.

Codon

A 3-nucleotide sequence in mRNA that specifies a particular amino acid or polypeptide formation signal; the basic unit of the genetic code.

Genetic Code

The amino acid translocations of each of the nucleotide triplets.

The five elements involved in the formation of a nucleic acid

Carbon, Hydrogen, Oxygen, Nitrogen, and Phosphorus

What is Ribose?

A five carbon sugar with hydroxyl (-OH) functional groups extending from the first, second, third, and fits carbon.

Ribose vs Deoxyribose

Ribose is only found in RNA; Deoxyribose, the sugar that forms when the -OH (hydroxyl) group is absent from the second carbon, is only found in DNA

The second subunit of a nucleotide

A phosphate radical group

Cytosine and Thymine have _____ and are called ______

Smaller, single ring structures; pyrimidines

Cytosine and Thymine have _____ and are called ______

Smaller, single ring structures; pyrimidines

The transcription enzyme RNA polymerase

Moves along the gene, forming a new RNA strand by following the base-pairing rules (U = T)

The promoter nucleotide sequence

Acts as a binding site for RNA polymerase and determines where transcription starts.

The terminator

Signals the end of a gene

What kind of RNA encodes amino acid sequences? Why are they called that?

Messenger RNA because it conveys genetic messages from DNA to the translation machinery of the cell.

Introns

Internal, noncoding regions of a gene that do not become part of the final messenger RNA molecule and therefore not expressed

Exons

Coding regions of a gene that are expressed

RNA Splicing

The removal of introns and joining of exons in eukaryotic RNA, forming an mRNA molecules with a continuous coding sequence; occurs before mRNA leaves the nucleus

What is the Function of a tRNA molecule? What are the two steps?

It’s to transfer amino acids from the Cytoplasmic Pool to a growing polypeptide in a ribosome; 1. Pick up the appropriate codons in the mRNA. 2. Recognize the Appropriate Codons in the mRNA.

Where are anticodons found? What are they?

Found on a tRNA molecule; specific sequences of three nucleotides that are complementary to a codon triplet of mRNA.

Ribosomes and what they consist of

Structures in the Cytoplasm that coordinate the functioning of mRNA and tRNA and catalyze the synthesis of Polypeptides. They consist of large and small subunits each made of proteins and ribosomal RNA (rRNA).

Stages of Translation

Initiation, Elongation, and Termination

Initiation

Brings together the mRNA, and tRNA bearing the first amino acid, and the two subunits of a ribosome.

Elongation

adds amino acids to a polypeptide chain

When does Elongation stop?

When a stop codon reaches the ribosome’s A-site

DNA Ligase

The glue for connecting the Okasagi Fragments

DNA polymerase

The Enzyme that catalyses the synthesis of DNA molecules

RNA Polymerase

The Enzyme that catalyzes chemical reactions that synthesizes RNA from a DNA Template

AUG is the only condon

That doesn’t start a the A-site of the EPA; all the others start at the A site

When finding the amino acids on a tRNA molecule, you look up

The mRNA codon

For an mRNA molecule, the 5’ side is the _______ and the 3’ side is the ________

Ifee’s Guanine Sequence; Poly A tail (multiple adenine nucleotides)

Reasons for 5’ CAP and 3’ Poly a Tale

Protection from degradation, Aiding the exit of he mature mRNA out through the nuclear pore, loved in the formation of the mRNA ribosomal complex

RNA Primers are used in the

Initiation of synthesizing a strand of DNA

Nonsense Mutation

When a sequence gives rise to a stop codon rather than a codon specifying an amino acid

Leading strands are assembled ____________________ a replication fork,

while lagging strands are assembled ___________________ the replication fork.

toward; away from

A geneticist found that a particular mutation had no effect on the polypeptide encoded by a gene. This mutation probably involved

Substitution of one nucleotide

DNA polymerase’s limitations include

Must add DNA nucleotides to the 3’ end of an existing strand

DNA cloning

The production of many identical copies of a target segment of DNA

Vector

Gene carrier

Clones

Population of genetically identical cells

Gene cloning

When DNA cloning involves a gene-carrying segment of DNA

Restriction Enzyme

A bacterial enzyme that cuts up foreign DNA (at specific DNA sequence called restriction sites)

Restriction fragments

Molecules of DNA produced from a longer DNA molecule cut up by a restriction enzyme

Reverse Transcriptase

A viral enzyme that can synthesize DNA from a RNA template

Yeast cells

Are often better than bacteria at synthesizing and secreting eukaryotic proteins

A vaccine

Is a harmless variant (mutant) or derivative of a pathogen — usually a bacterium or virus — that is used to stimulate the immune system to mount a lasting defuse against that pathogen, thereby preventing diseases