DNA Structure & Chromosomes

Flashcards covering DNA structure, chromosomes, and DNA replication.

DNA (deoxyribonucleic acid) __

Stores genetic information in all cells and is very large.

RNA (ribonucleic acid) __

Is necessary for converting DNA’s information into proteins.

Nucleotides are made of a 5-carbon __

Ribose in RNA and Deoxyribose in DNA

Bases with 1 ring are known as Pyrimidines: __

Thymine (T), Cytosine (C), and Uracil (U)

Bases with 2 rings are known as Purines: __

Adenine (A) and Guanine (G)

DNA is __

2 strands of nucleic acids wrapped around each other in a double helix.

RNA is __

Single stranded nucleic acid

Nucleotides form nucleic acids by the __ reaction

Removing water forms a covalent bond between the phosphate of one nucleotide and the sugar of the second nucleotide.

The backbone of single stranded nucleic acids (RNA) is made of __

Alternating sugar and phosphate.

The backbone of double-stranded nucleic acids (DNA) is made of __

Alternating sugar and phosphate.

Antiparallel strands of DNA __

Run in opposite directions so they lie “head-to-toe” with each other, making a stable double helix.

The terminology of 5' (5-prime) end and 3' (3-prime) end refers to __

The 5' and 3' carbons on the sugar.

In complementary base pairing, the 2-ring purine __

A pairs with T with 2 hydrogen bonds and G pairs with C with 3 hydrogen bonds.

Chromosomes are __

Linear pieces of DNA bound to proteins called histones.

Genes are __

Segments of DNA that is copied into RNA.

DNA is doubled __

By exactly copying the bases to make two DNA strands.

The three steps in the process of DNA replication are __

Initiation, Elongation, and Termination.

During initiation, proteins bind to the origin of replication, which is the __

Point where replication begins.

During initiation, __ unwinds the DNA helix.

An enzyme called helicase.

During elongation, __ adds DNA nucleotides to the 3' end of the newly synthesized polynucleotide strand.

An enzyme called DNA polymerase.

All newly synthesized polynucleotide strands must be initiated by __

A specialized RNA polymerase called primase.

DNA polymerase can only synthesize new strands __

In the 5' to 3' direction.

The leading strand is __

Synthesized continuously toward the replication fork.

The lagging strand is __

Synthesized in the direction away from the replication fork and away from where the DNA helicase unwinds.

The pieces that make up the lagging strand are called __

Okazaki fragments.

In the final stage of DNA replication, __ joins the sugar-phosphate backbones at each nick site.

The enzyme ligase.

A prokaryote has ___

DNA in cytoplasm, circular chromosome, and divides via binary fission.

A eukaryote has __

DNA in nucleus, linear chromosome, and divides by mitosis.

Mutations are __

Changes on the DNA usually involving only 1 to 10 bases.

A missense mutation is __

A change in one DNA base pair that results in the substitution of one amino acid for another in the protein made by a gene.

In a nonsense mutation, __

The altered DNA sequence prematurely signals the cell to stop building a protein.

An insertion __

Changes the number of DNA bases in a gene by adding a piece of DNA.

A deletion __

Changes the number of DNA bases by removing a piece of DNA.

A duplication __

Consists of a piece of DNA that is abnormally copied one or more times.

A frameshift mutation __

Occurs when the addition or loss of DNA bases changes a gene's reading frame.

A repeat expansion __

Short DNA sequences are repeated a number of times in a row.