BIO 1111 - Chapter 9 Study Guide: Cell Cycle, DNA Replication, and Mitosis

Flashcards covering cell types, prokaryotic genetic transfer and division, eukaryotic chromosomes, stages of the cell cycle, and DNA structure and bonding from Page 1 of the Chapter 9-10 study guide.

How does the structure of a prokaryotic cell differ from a eukaryotic cell?

Prokaryotic cells (such as bacteria) lack a membrane-bound nucleus and other membrane-bound organelles, storing DNA as a circular chromosome in a nucleoid region. Eukaryotic cells contain a nucleus with linear chromosomes and membrane-bound organelles (such as mitochondria), and are generally larger and more complex.

What are the primary causes of genetic variation in prokaryotes?

Genetic variation in prokaryotes comes from mutations in DNA and horizontal gene transfer (transformation, transduction, and conjugation).

What is transformation in bacteria?

A mechanism of horizontal gene transfer where bacteria acquire DNA by taking it up directly from the environment.

What is transduction in bacteria?

A mechanism of horizontal gene transfer where DNA is transferred into bacteria by viruses called bacteriophages.

What is conjugation in bacteria?

A mechanism of horizontal gene transfer where DNA is transferred directly between cells, often through a pilus.

What are the sequential events of binary fission in prokaryotes?

The prokaryotic chromosome is copied; the cell grows and the two DNA copies move apart as the membrane elongates; then the membrane and cell wall pinch inward, dividing the cell into two genetically similar daughter cells.

How does a typical eukaryotic chromosome differ from a prokaryotic chromosome?

A typical eukaryotic chromosome is linear, associated with histone proteins, located in the nucleus, and usually present in multiples. A typical prokaryotic chromosome is circular, located in the nucleoid region, and not enclosed in a nucleus.

What are plasmids?

Small circles of DNA found in some prokaryotes in addition to their main circular chromosome.

What are the two major phases of the cell cycle and what occurs during each?

The cell cycle consists of interphase (where the cell grows, performs normal functions, copies DNA, and prepares for division) and the mitotic (M) phase (where mitosis separates duplicated chromosomes into two nuclei and cytokinesis divides the cytoplasm).

What happens during the G1, S, and G2 stages of interphase?

In G1, the cell grows, makes proteins and organelles, and carries out normal functions. In S, DNA replicates so each chromosome consists of two sister chromatids. In G2, the cell grows further, checks/repairs DNA as needed, and prepares machinery for division.

What is the G0 phase of the cell cycle?

A nondividing state that some cells enter instead of proceeding through the active cell cycle.

How did Watson and Crick describe the structure of DNA?

DNA is a double helix consisting of two antiparallel nucleotide strands made of deoxyribose sugar, a phosphate group, and a nitrogenous base. The sugar-phosphate backbones are on the outside, and complementary base pairs (adenine with thymine, guanine with cytosine) are on the inside.

What bonds hold complementary base pairs together in DNA, and how many are between each pair?

Hydrogen bonds hold the bases together: adenine pairs with thymine using two hydrogen bonds, and guanine pairs with cytosine using three hydrogen bonds.

What type of chemical bonds connect the sugar-phosphate backbone within each DNA strand?

Strong covalent phosphodiester bonds connect the sugar-phosphate backbone within each strand.