Quiz Replication

Genotype

Genetic information.

Phenotype

Observable traits or characteristics resulting from the interaction of genotype and environment.

DNA

Can be copied quickly and accurately and can be passed down from generations.

Antiparallel

Refers to the opposite orientation of the two strands of DNA.

Semi-conservative replication

Process in which half of the DNA molecule is conserved in each new copy.

Template DNA

The original DNA strands that serve as a pattern for replication.

Deoxyribonucleic triphosphates (dNTPs)

The building blocks that come together during DNA replication.

Phosphodiester bond

The bond formed between the sugar of one nucleotide and the phosphate of another during DNA replication.

Helicase

Enzyme that unzips the DNA double helix to allow replication.

Gyrase

Enzyme that prevents DNA from twisting too tightly during replication.

Primase

Enzyme that lays down a short piece of RNA primer for replication to begin.

DNA polymerase

Enzyme that adds deoxyribonucleotides to build a new strand of DNA.

Ligase

Enzyme that seals gaps between newly replicated pieces of DNA.

Telomerase

Enzyme that replicates the ends of chromosomes (telomeres).

Origins of replication

Specific spots where DNA replication begins.

Single-stranded-binding proteins

Proteins that keep the two strands of DNA apart during replication.

Bidirectional replication

DNA replication that proceeds in both directions away from the origin.

Okazaki fragments

Short pieces of DNA formed during the replication of the lagging strand.

Exonuclease activity

The process of cutting out incorrect bases added by DNA polymerase during proofreading.

Mismatch repair

The process by which enzymes correct errors missed during proofreading.

Non-coding DNA

DNA that does not encode for proteins, such as telomeres.

Histones

Proteins around which DNA is tightly wrapped to form nucleosomes.

Theta replication

The shape that a bacterial chromosome takes on during replication, forming a bubble with one origin.

Rolling circle replication

Type of replication where a broken strand provides a free OH tail to start replication.

D-loop replication

Replication mechanism that creates a displaced single strand as helicase opens the double-stranded molecule.

3’ end

The end of a DNA strand that has a hydroxyl group and is crucial for nucleotide bonding during replication.

5’ end

The end of a DNA strand opposite the 3’ end that has a phosphate group.

DNA replication speed

The rate of DNA synthesis; approximately 2000 bases per minute in bacteria.

Leading strand

The DNA strand synthesized continuously in the same direction as the replication fork.

Lagging strand

The DNA strand synthesized discontinuously in short pieces opposite to the direction of the replication fork.

RNA primers

Short sequences of RNA that provide a starting point for DNA synthesis.

Telomeres

Repeated sequences of non-coding DNA at the ends of linear chromosomes.

Apoptosis

Programmed cell death that can occur when chromosomes become too short.

Nucleosomes

Structures formed by DNA wrapped around histone proteins.

16S rRNA

A component of the ribosome that helps in protein synthesis.

Chromosomes

Structures that contain an organism's DNA.

dNTPs

The building blocks of DNA used during the replication process.

Proofreading

The ability of DNA polymerase to correct mistakes made during DNA synthesis.

Gyrase in eukaryotes

Referred to as topoisomerases, which help relieve stress during DNA replication.

Replication fork

The Y-shaped region where the DNA is split into two strands for replication.

Replication in Eukaryotes

Involves multiple DNA polymerases and origins of replication.

Histone chaperones

Proteins that assist in disassembling and reassembling nucleosomes during DNA replication.

Hydroxyl group

The functional group present on the 3’ end of DNA that allows for the attachment of dNTPs.

Gene expression regulation

Control of the timing and amount of gene product produced.

Covalent bonds

Strong bonds formed between atoms, critical in maintaining the structure of DNA.

Exponential growth of DNA

Refers to the doubling of DNA sequences during replication.

Transcription

The process by which DNA is copied into RNA.

Translation

The process by which RNA is used to synthesize proteins.

Cell cycle

The series of phases that a cell goes through as it grows and divides.

Genetic diversity

The total number of genetic characteristics in a species.

Hershey and Chase

1952 proved DNA is the genetic material, not proteins

Chargaff

~ 1950 noticed a consistent pattern in DNA across species involving base pair amounts

Chargaff’s Rules

A pairs with T, and G pairs with C

Rosaline Franklin and Maurice Wilkins

1952 used -ray crystallography to study the physical shape of DNA

Photo 51

Rosalind Franklin’s photo, X-shaped pattern strong evidence for DNA as a helix

controversy

Watson and Crick used Rosalind’s work without her knowledge or permission, gave them a major piece of evidence to finalize their model. Rosalind did not get full credit

Watson and Crick

1953 proposed the Double Helix model of DNA—published it in Nature, won the 1962 Nobel Peace Prize (w/out Rosalind, she passed away)

Parts of a nucleotide

a phosphate group, a pentose sugar, and a nitrogenous base

purines

Adenine and guanine

pyridimines

thymine and cytosine

sugar phosphate backbone

sides of the ladder made of alternating sugar and phosphate molecules

how are nitrogenous bases held together?

hydrogen bonds

shape of DNA

double helix

antiparallel

DNA strands run in opposite directions (5’ - 3’ or 3’ - 5’) —essential for how DNA is copied and later read by the cell

where is DNA located?

nucleus

chromomes

DNA tightly wound and packaged into structures called chromosomes