DNA Replication & Transcription Vocabulary

Questions and Answers

What is DNA?

A long linear polymer found in the nucleus of a cell (correct)

A type of sugar

A fatty acid

A type of protein

What are nucleosomes?

Beads on a string formed by DNA wound around a protein core of histone molecules.

What is chromatin?

A combination of DNA and protein molecules in the nucleus of a eukaryotic cell.

What is a hydrogen bond?

A chemical bond consisting of a hydrogen atom between two electronegative atoms. Signup and view all the answers

What is a complementary strand?

A newly synthesized strand of RNA or DNA with a base sequence complementary to the template strand. Signup and view all the answers

What is DNA replication?

The process by which DNA is copied in a cell before it divides. Signup and view all the answers

What is the function of DNA helicase?

An enzyme that breaks the hydrogen bonds between bases during DNA replication. Signup and view all the answers

What does DNA polymerase I do?

Removes RNA primers and replaces them with the appropriate nucleotides. Signup and view all the answers

What is DNA polymerase III?

An enzyme that catalyzes the elongation of new DNA at a replication fork. Signup and view all the answers

What is the role of RNA primase?

An enzyme that creates an RNA primer for the initiation of DNA replication. Signup and view all the answers

What does DNA ligase do?

A linking enzyme essential for DNA replication that catalyzes covalent bonding. Signup and view all the answers

What are Okazaki fragments?

Short segments of DNA synthesized away from the replication fork. Signup and view all the answers

What is a replication fork?

A Y-shaped region on a replicating DNA molecule. Signup and view all the answers

What is the origin of replication?

Site where the replication of a DNA molecule begins. Signup and view all the answers

What is the semiconservative model?

Type of DNA replication where the replicated helix consists of one old and one new strand. Signup and view all the answers

What is the leading strand?

The new continuous complementary DNA strand synthesized in the 5' to 3' direction. Signup and view all the answers

What is the lagging strand?

The newly forming daughter strand of DNA that is replicated in a discontinuous fashion. Signup and view all the answers

What is the role of single-strand binding protein?

A protein that binds to unpaired DNA strands during replication. Signup and view all the answers

What is a mutation?

Any event that changes the genetic structure. Signup and view all the answers

What are carcinogens?

Substances and agents that are known to cause cancer. Signup and view all the answers

What is transcription?

The process whereby the DNA sequence in a gene is copied into mRNA. Signup and view all the answers

What is the sense strand?

The DNA strand that is represented on paper, running from 5' to 3'. Signup and view all the answers

What is the antisense strand?

The non-coding strand that serves as a template for mRNA transcribed. Signup and view all the answers

What is a promoter?

Region of DNA that indicates where to bind to make RNA. Signup and view all the answers

What does RNA polymerase do?

Enzyme that links together RNA nucleotides during transcription. Signup and view all the answers

What are transcription factors?

Collection of proteins that mediate the binding of RNA polymerase. Signup and view all the answers

What is a terminator?

A special sequence of nucleotides that marks the end of a gene. Signup and view all the answers

Study Notes

DNA and Its Structure

DNA (Deoxyribonucleic Acid) is a long polymer located in cell nuclei, composed of nucleotides and structured as a double helix.
Nucleosomes are structures formed by DNA coiling around a core of eight histone proteins, resembling "beads on a string."
Chromatin is a complex of DNA and protein fibers that constitutes genetic material in eukaryotic cell nuclei.

Chemical Bonds and Base Pairing

Hydrogen bonds link complementary base pairs in DNA, involving a hydrogen atom between electronegative atoms (such as oxygen or nitrogen).

DNA Replication Process

DNA replication is the biological process in which DNA is duplicated prior to cell division through mechanisms like mitosis and meiosis.
DNA helicase is the enzyme that unwinds the DNA double helix by breaking hydrogen bonds between base pairs.
DNA Polymerase I removes RNA primers and replaces them with nucleotides, while DNA Polymerase III elongates the DNA strand by adding nucleotides.
RNA primase synthesizes a short RNA primer needed for DNA replication initiation.
DNA ligase links DNA fragments together by forming covalent bonds between the growing DNA chain and newly synthesized fragments.

Key Components of DNA Replication

Okazaki fragments are short DNA sequences synthesized on the lagging strand, later joined together to form a continuous strand.
The replication fork is a Y-shaped region where parental DNA strands separate, allowing new strands to form.
The origin of replication is the specific nucleotide sequence that initiates DNA replication.

Models and Mechanisms of DNA Replication

The semiconservative model of replication results in each new double helix containing one old and one new strand.
The leading strand is synthesized continuously in the 5' to 3' direction, while the lagging strand is assembled in a discontinuous manner opposite to the direction of unwinding.

Additional Factors in DNA Replication

Single-strand binding proteins stabilize unpaired DNA strands during replication to prevent them from re-annealing or degrading.
Mutations are changes in the genetic structure that can result from various factors, including exposure to carcinogens which are substances known to cause cancer.

Transcription Process

Transcription converts the DNA sequence of a gene into messenger RNA (mRNA).
The sense strand of DNA is the strand that is transcribed into mRNA and runs from 5' to 3', with thymine replaced by uracil in RNA.
The antisense strand acts as the template for mRNA synthesis and is the non-coding strand during transcription.

Transcriptional Regulation

The promoter region on DNA indicates where RNA polymerase binds to initiate transcription.
RNA polymerase links RNA nucleotides to form a growing mRNA chain based on the DNA template.
Transcription factors are proteins that regulate the binding of RNA polymerase and help start the transcription process.
The terminator is a specific nucleotide sequence that signifies the end of gene transcription.

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Description

Enhance your understanding of key vocabulary related to DNA replication, transcription, and translation with these flashcards. Each term is defined to help solidify your grasp of biochemistry concepts essential for studying genetics.