Complete Biology Study Notes — Second Partial (Sections 3.1 to 3.6)

A comprehensive set of flashcards covering the critical concepts, processes, and terminology related to the biochemical structure of DNA and RNA, their functions, and related biological processes including replication, transcription, translation, and types of mutations.

What does DNA stand for and what is its primary function?

Deoxyribonucleic Acid; it stores genetic information in living organisms.

What does RNA stand for and what role does it play in protein synthesis?

Ribonucleic Acid; it carries and translates genetic instructions for protein synthesis.

What are the components of a nucleotide?

One phosphate group, one pentose sugar, and one nitrogenous base.

What is the sugar found in DNA and RNA?

DNA has deoxyribose sugar; RNA has ribose sugar.

What are the nitrogenous bases in DNA?

Adenine (A), Thymine (T), Cytosine (C), Guanine (G).

What are the nitrogenous bases in RNA?

Adenine (A), Uracil (U), Cytosine (C), Guanine (G).

What base pairing rule applies to DNA?

Adenine pairs with Thymine; Cytosine pairs with Guanine.

What base pairing rule applies to RNA?

Adenine pairs with Uracil; Cytosine pairs with Guanine.

What are purines and pyrimidines?

Purines are nitrogenous bases with two rings (Adenine and Guanine); Pyrimidines have one ring (Cytosine, Thymine, and Uracil).

Who were the three scientists key in discovering the structure of DNA?

Rosalind Franklin, James Watson, and Francis Crick.

What did Rosalind Franklin contribute to the discovery of DNA structure?

She used X-ray diffraction to obtain Photograph 51, showing DNA had a helical shape.

What is the double helix model of DNA?

DNA consists of two antiparallel strands twisted around each other, with a sugar-phosphate backbone and nitrogenous bases inside.

What is the purpose of DNA replication?

To produce an exact copy of DNA before cell division.

What does semiconservative replication mean?

Each new DNA molecule contains one original parent strand and one newly synthesized strand.

What are the three stages of DNA replication?

Initiation, Elongation, and Termination.

What enzyme unzips DNA during replication?

Helicase.

What are Okazaki fragments?

Short DNA segments synthesized discontinuously on the lagging strand.

What is the function of RNA polymerase during transcription?

It reads the DNA strand and forms complementary RNA nucleotides.

What is a codon?

A sequence of three nitrogenous bases on mRNA that codes for one amino acid.

What is an anticodon?

The complementary three-base sequence on tRNA.

What is the start codon and what does it signify?

AUG; it codes for methionine and signals the beginning of translation.

What are stop codons?

UAA, UAG, UGA; they signal the end of protein synthesis.

What is the difference between replication, transcription, and translation?

Replication makes DNA, transcription makes mRNA, and translation makes protein.

What are gene or point mutations?

Mutations affecting one or a few nucleotides.

What is a substitution mutation?

One base is replaced by another.

What happens during an insertion mutation?

One or more bases are added to the DNA sequence.

What happens during a deletion mutation?

One or more bases are removed from the DNA sequence.

What are chromosomal mutations?

Mutations that affect the structure of chromosomes.

Name the four types of chromosomal mutations.

Deletion, Duplication, Inversion, Translocation.

What is aneuploidy?

A condition involving extra or missing chromosomes.