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Questions and Answers

What is DNA Helicase responsible for?

Transporting amino acids

Connecting Okazaki fragments

Unwinding and unzipping the double helix (correct)

Adding new nucleotides

What do Single Stranded Binding proteins do?

They keep the DNA strands separate during replication.

What does RNA Primase add to each strand of DNA?

RNA Primer

What does DNA Polymerase do?

Adds new nucleotides to the 3' end of the new strand. Signup and view all the answers

What characterizes the Leading Strand?

It is built continuously with nucleotides added to the 3' end. Signup and view all the answers

What are Okazaki Fragments?

Segments synthesized discontinuously on the lagging strand. Signup and view all the answers

What is the direction of elongation for the Lagging Strand?

Away from the replication fork. Signup and view all the answers

What is the function of DNA Ligase?

To connect the Okazaki Fragments. Signup and view all the answers

How is RNA structured compared to DNA?

It is single stranded with alternating chains of phosphate and sugar. Signup and view all the answers

What type of sugar does RNA contain?

Ribose Signup and view all the answers

What are the nitrogen bases for RNA?

Adenine, Guanine, Cytosine, Uracil Signup and view all the answers

What is the role of Messenger RNA?

Directs the synthesis of specific proteins. Signup and view all the answers

What do Ribosomal RNA and proteins form?

Ribosomes Signup and view all the answers

What is the function of Transfer RNA?

Transport amino acids to the ribosome. Signup and view all the answers

In Transcription, DNA unzips, and only one side acts as a template, forming ____

mRNA Signup and view all the answers

What regulates RNA synthesis?

RNA Polymerase Signup and view all the answers

What binds temporarily to the DNA strand during transcription?

Complementary Nucleotide Signup and view all the answers

What are Exons?

Coding sequences that remain in the final mRNA. Signup and view all the answers

Processed mRNA carries the appropriate coding sequence and ____ the nucleus.

leaves Signup and view all the answers

What happens to the DNA strands after transcription?

They zip back together. Signup and view all the answers

Where are the instructions for Protein Synthesis encoded?

In the DNA. Signup and view all the answers

_ amino acids are used to make proteins, so DNA must provide for _ different codes.

Twenty Signup and view all the answers

What is a Codon?

Every three bases on mRNA that codes for one amino acid. Signup and view all the answers

What happens to mRNA after it is synthesized?

It moves out of the nucleus to the ribosome in the cytoplasm. Signup and view all the answers

What attaches to the ribosome's 5' end?

mRNA Signup and view all the answers

What do tRNA molecules do?

Act as interpreters of the mRNA codon sequence. Signup and view all the answers

What is an Anticodon?

A series of three bases on tRNA. Signup and view all the answers

Study Notes

DNA Structure and Replication

DNA Helicase: Enzyme that unwinds and unzips the double helix by breaking hydrogen bonds between strands.
Single Stranded Binding Proteins: Stabilize separated DNA strands during replication to prevent reannealing.
RNA Primase: Synthesizes a short RNA primer for DNA replication initiation on both strands.
DNA Polymerase: Enzyme that adds new nucleotides to the 3' end of a growing DNA strand.
Leading Strand: Synthesized continuously toward the replication fork, with nucleotides added to the 3' end.
Lagging Strand: Synthesized discontinuously away from the replication fork, forming Okazaki fragments.
Okazaki Fragments: Short segments of DNA on the lagging strand that are joined later.
DNA Ligase: Enzyme that connects Okazaki fragments, completing the lagging strand.

RNA Composition and Function

RNA: Single-stranded nucleic acid with a structure similar to DNA but contains ribose and uracil instead of thymine.
Ribose: Sugar component in RNA, differing from deoxyribose in DNA.
Nitrogen Bases in RNA: Include adenine, guanine, cytosine, and uracil.

Types of RNA

Messenger RNA (mRNA): Long strands of RNA that carry genetic information from DNA to the ribosome for protein synthesis.
Ribosomal RNA (rRNA): Forms the core component of ribosomes, facilitating protein synthesis in the cytoplasm.
Transfer RNA (tRNA): Smaller RNA molecules that transport amino acids to the ribosome, crucial for assembling proteins.

Transcription Process

Transcription: DNA unzips, and one strand serves as a template to synthesize mRNA.
RNA Polymerase: The enzyme responsible for synthesizing RNA from the DNA template during transcription.
Complementary Nucleotide: Binds to the DNA strand during transcription to form mRNA.
Introns and Exons: Introns are non-coding sequences removed during RNA processing; exons are the coding sequences that remain in the final mRNA.

mRNA Processing and Translation

Processed mRNA: Carries the coding sequence for protein synthesis and exits the nucleus into the cytoplasm.
Protein Synthesis: Instructions encoded in DNA dictate the formation of proteins.
Amino Acids: There are twenty different amino acids that make up proteins, requiring twenty different codes.
Codon: A sequence of three bases on mRNA that encodes a specific amino acid.
Anticodon: A series of three bases on tRNA that base-pairs with the corresponding mRNA codon during translation.
Ribosome Attachment: The 5' end of mRNA attaches to the ribosome to initiate protein synthesis.