Cell division, Eukaryotic Chromosomes, and DNA Packaging

Question 1

What is cell division?

Answer 1

Orderly sequence of events in which cell duplicates its contents and divides in two.

Question 2

What are unicellular and metazoans organisms?

Answer 2

Unicellular (bacteria, yeast, protozoa) generate a complete new organism when they divide. Metazoans also known as multicellular organisms, go through many cell divisions to generate a new organism.

Question 3

What features of cell division are universal?

Answer 3

• Have to faithfully replicate DNA
• Replicated DNA must be accurately distributed to daughter cells
• Most cells also duplicate their other macromolecules and organelles and double in size before they divide

Question 4

What is mitosis?

Answer 4

• When cell divides it splits into a genetically identical cell
• Division of genetic material produces daughter cells
• Accompanied with cytokinesis

Question 5

Which cells needs wear ‘n’ tear, wound repair?

Answer 5

Epithelial cells

Question 6

Eukaryotic Chromosomes

Answer 6

• Multiple linear chromosomes in the nucleus
• Two copies of each
• Mosy eukaryotes have 10-50
• Humans have 46 chromosomes and 23 pairs (2n)
• Complex packaging of DNA

Question 7

DNA packaging in Eukaryotes

Answer 7

-DNA double helix wrapped around histone proteins
- Tightly packed DNA w/ histones
- Chromosome in extended form (most of the time spent in this form/not visible)
- Condensation in preparation for mitosis/meiosis
- Entire mitotic chromosome
(highly condensed and now visible)

Condensation increases

Question 8

Homologous Chromosomes vs Sister Chromosomes

Answer 8

Homologous chromosomes are one chromosome. Sister chromatids are the one parental homolog and the other replicated homolog.