Bio exam 4 (RNA)

What are the differences between DNA and RNA?

• Sugar: DNA contains deoxyribose; RNA contains ribose.

• Bases: DNA uses thymine (T); RNA replaces it with uracil (U).

• Structure: DNA is typically double-stranded; RNA is usually single-stranded.

What are the three types of RNA, which direction is it synthesized?

• mRNA (Messenger)

• tRNA (Transfer)

• rRNA (Ribosomal)

Synthesized in the 3’ to 5’ direction

What does mRNA do, what is its structure

• mRNA (Messenger): Carries the genetic "blueprint" from DNA to the ribosome.

structure: single stranded nucleus acid

What does tRNA do, what is its structure

tRNA (Transfer): Delivers specific amino acids to the ribosome based on the mRNA code.

structure: nucleotide single stranded rna chain that folds into a 2d clover shape

What does rRNA do, what’s its structure

rRNA (Ribosomal): Forms the physical structure of the ribosome and catalyzes protein synthesis

Structure: folded single strand of rna

What’s the process of transcription

Process: Copying a DNA segment into RNA.

What enzymes are involved in transcription

Enzyme: RNA Polymerase is the primary enzyme responsible

Inputs and outputs of transcription

Inputs: DNA Template, RNA Polymerase, nucleoside triphosphates (ATP, CTP, GTP, UTP), Transcription Factors

Outputs: RNA Transcript (mRNA, tRNA, or rRNA), Pyrophosphate

Location of transcription

Nucleus of eukaryotic cells

What is rna processing and what does it result in

RNA processing is "pre-mRNA" is modified before leaving the nucleus. This results in a mature mRNA through:

1. Splicing: Removing non-coding sequences (introns) and joining coding sequences (exons).

2. 5' Cap: Adding a protective modified guanine cap.

3. Poly-A Tail: Adding a string of adenine nucleotides to the 3' end for stability

Location, definition, and Role of Codons in transcription

• Definition: A sequence of three consecutive nucleotides on the mRNA strand.

• Role: Each codon specifies one particular amino acid (or a start/stop signal) to be added to the polypeptide chain.

• Location: They are found along the length of the mRNA molecule and are "read" by ribosomes in the cytoplasm.

What is dna polymerase and its roles

enzyme responsible for DNA replication, which occurs before a cell divides.

• Primary Function: It "reads" an existing DNA strand and assembles a new, complementary strand of DNA.

• Key Role: Ensuring that genetic information is accurately copied so that each new daughter cell receives a complete set of instructions.

What is rna polymerase and its roles

This enzyme is the central player in transcription, the first step of gene expression.

• Primary Function: It binds to a specific gene on the DNA and uses it as a template to build a strand of messenger RNA (mRNA).

• Key Role: It "transcribes" the genetic code from the permanent DNA storage into a portable RNA format that can be used by the ribosome to build proteins.