Chromosomes Flashcards Preview

MCAT Biology > Chromosomes > Flashcards

Flashcards in Chromosomes Deck (11):
1

what is the purpose of a chromosome

to efficiently package long strands of DNA to be stored between divisions, and moved during divisions

2

histones

Histones are the proteins around which the DNA helix is wrapped when condensed into chromosomes

3

nucleosomes

A nucleosome is a set of 8 histone proteins in a cube shape with DNA coiled around it much like thread around a spool. There is further coiling and supercoiling of the nucleosomes to create the final condensed chromosome

4

chromatin

Chromatin is a general term for DNA + protein. Therefore, chromosomes are made up of chromatin.

5

diploid

A diploid cell has 2n chromosomes. Diploid cells have two copies of each chromosome

6

haploid

a haploid cell has n chromosomes. haploid cells have only one copy of each chromosome

7

homologues

Homologues are two related but non-identical chromosomes—one originating from each parent.

8

sister chromatids

Sister chromatids are the two strands of DNA in a duplicated chromosome attached by a centromere. Assuming no mutations or errors in replication, they are identical as long as crossing over has not occurred.

9

centromere

The centromere is the region of the chromosome that joins the two sister chromatids.

10

kinetochore

The term kinetochore is often used synonymously with centromere, but they are not identical. The centromere is a region on the chromosome and the kinetochore is a specialized group of proteins to which the spindle fibers attach directly during mitosis/meiosis.

11

Where is DNA found in the cell

Nuclear DNA is found in the nucleus and never leaves the nucleus. However, mitochondria also contain DNA—although it is their own unique-lineage circular DNA, NOT nuclear DNA.