Unit 5 Study Guide

Nucleotides

Building blocks of DNA, composed of a deoxyribose sugar, a phosphate group, and a nitrogenous base.

DNA Backbone

Made of alternating 5-carbon sugar (deoxyribose) and phosphate groups.

Complementary Base Pairing

A pairs with T (2 hydrogen bonds); C pairs with G (3 hydrogen bonds).

Purines vs. Pyrimidines

Purines: Adenine (A) and Guanine (G) (double-ringed structures); Pyrimidines: Cytosine (C) and Thymine (T) (single-ringed structures).

Phosphodiester Bonds

Covalent bonds linking nucleotides in the DNA backbone.

Hydrogen Bonds

Hold complementary bases together in a DNA molecule.

Gene

A segment of DNA that codes for a protein.

Double Helix

The structure of DNA, allowing for compact storage and stable transmission of genetic information.

Transcription

The process of creating an mRNA copy of a DNA sequence.

Translation

The process of converting mRNA into a protein.

Mutation

A change in the DNA sequence.

Substitution Mutation

A mutation where one nucleotide is replaced with another.

Silent Mutation

A type of substitution mutation that results in no change in the amino acid sequence.

Missense Mutation

A mutation that changes one amino acid in a protein, potentially altering its function.

Nonsense Mutation

A mutation that creates a stop codon, leading to a shortened protein.

Frameshift Mutation

A mutation caused by insertion or deletion of nucleotides, shifting the reading frame.

tRNA

Transfer RNA, which brings amino acids to the ribosome during protein synthesis.

Ribosome

The cellular structure that reads mRNA and facilitates the synthesis of proteins.

Anticodons

Sequences on tRNA that are complementary to mRNA codons.

Amino Acids

The building blocks of proteins linked together during translation.

mRNA

Messenger RNA, which carries genetic information from DNA to the ribosome for protein synthesis.

rRNA

Ribosomal RNA, which is a structural component of ribosomes and plays a crucial role in protein synthesis.

tRNA

Transfer RNA, which delivers amino acids to the ribosome based on the sequence of codons on the mRNA.

snRNA

Small nuclear RNA, involved in the process of splicing and modification of pre-mRNA in the nucleus.

siRNA

Small interfering RNA, a type of RNA that can silence gene expression by targeting mRNA for degradation.