Biology Chapter: DNA Transformation Experiments

A complex of proteins that coordinates the replication of both the leading and lagging strands of DNA, ensuring that both strands are synthesized simultaneously.

The direction in which the replisome moves along the DNA during replication, following the direction of the replication fork.

A mechanism used by DNA polymerase to correct errors during DNA replication by removing and replacing incorrectly incorporated nucleotides.

A DNA repair mechanism that removes bulky DNA damage caused by various agents like radiation or specific chemicals.

The ability of DNA polymerase to only add nucleotides to the 3' end of a growing DNA strand.

The process of creating a new DNA molecule that is identical to the original DNA molecule. Semi-conservative replication is where each new DNA molecule consists of one original strand and one newly synthesized strand.

When the DNA density is intermediate after one replication round, it suggests that each new DNA molecule has one old (heavy) strand and one new (light) strand. This supports the semi-conservative model.

A specific sequence of DNA where replication begins. It's like the starting point for copying the DNA.

Prokaryotes have a single origin of replication, while eukaryotes have multiple origins of replication, allowing for more efficient replication of their larger genomes.

A protein complex that recognizes and binds to the origin of replication, initiating the replication process in eukaryotes.

Enzymes that unwind the DNA double helix at the origin of replication, making the DNA strands accessible for copying.

Enzymes that synthesize new DNA strands using the existing strands as templates. They add new nucleotides onto the growing DNA chain.

The process of replicating DNA is generally faster in eukaryotes due to the presence of multiple origins of replication. This allows for more efficient copying of the larger eukaryotic genomes.

A protein that binds to single-stranded DNA, preventing it from rejoining after being separated by helicase.

A type of nucleotide specifically used in DNA synthesis that provides the building blocks for the new DNA strand. It contains deoxyribose sugar, a phosphate group, and one of the four nitrogenous bases (adenine, guanine, cytosine, or thymine).

The way DNA polymerase adds nucleotides to a growing DNA strand, always in the 5' to 3' direction.

The addition of a new nucleotide to the growing DNA strand involves forming a phosphodiester bond between the 5' phosphate group of the incoming nucleotide and the 3' hydroxyl group of the last nucleotide on the strand.

The existing strand of DNA that serves as a template for the new strand to be synthesized during DNA replication.

A permanent change in the DNA sequence that can be passed on to offspring. It's the source of genetic diversity and evolution.

A DNA repair mechanism that removes damaged or incorrect nucleotides and replaces them with the correct ones.

The problem that arises when DNA polymerase cannot create a new DNA strand without a primer at the end of a linear chromosome, leading to shortening of the chromosome.

Specialized DNA sequences at the ends of chromosomes in eukaryotes that protect against the loss of important genetic information during replication.

The enzyme that adds repetitive DNA sequences to the ends of telomeres in germ cells, preventing the shortening of chromosomes.

The process by which mistakes or damage in DNA can become permanent changes in the genetic code.

The shortening of chromosomes during replication due to the lack of a primer at the end, leading to the loss of genetic material.

The specialized DNA sequences at the ends of chromosomes that help protect against the loss of important genetic information during replication, but they don't prevent shortening completely.

Composed of DNA and proteins, chromosomes contain genetic information tightly packed into structures. There are two main types: euchromatin and heterochromatin.

A type of chromatin where DNA is less tightly packed, allowing genes to be accessed and transcribed. Think of it as 'active' DNA.

A type of chromatin where DNA is tightly packed, making genes inaccessible for transcription. Think of it as 'inactive' DNA.

Basic units of chromatin, resembling beads on a string. They are made of DNA wrapped around proteins called histones.

The process of copying DNA into RNA, allowing for gene expression and protein production.

Acetylation of histone proteins loosens the DNA packaging, making genes more accessible for transcription and increasing gene expression.

Methylation of histone proteins tightens the DNA packaging, making genes less accessible for transcription and decreasing gene expression.

Epigenetics refers to changes in gene expression caused by mechanisms other than alterations in the DNA sequence itself, like methylation. These modifications can be influenced by environmental factors and can be inherited.

The 3' end of a DNA strand has a hydroxyl group (OH), while the 5' end has a phosphate group.

DNA polymerases can only add nucleotides to the 3' end of a growing DNA strand because the phosphate group on the 5' end is too electronically dense for the enzyme to add nucleotides.