Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

35 Cards in this Set

  • Front
  • Back

What is the Definition of a Genome?

The complete haploid genetic information of a cell or organism, DNA that contains that information

-Human genome = 3.2 billion bp

Eukaryotic Chromosomes

Chromosomes: DNA and proteins

DNA stretched out = 2 meters long

DNA must be packaged to fit inside nucleus of cell

What are the three elements of a chromosome?

Telomere: Caps on tails of DNA

Replication Origin: Can be multiple

Centromere: heterochromatic region where kinetochore assembles. Links sister chromatids in the middle of the X where they link

DNA packaging

46 chromosomes total

22 from father

22 from mother

2 sex chromosomes

Chromosomes are made from chromatin.


2 copies, diploid, "homologous chromosomes"


DNA wraps around histone for a "bead on a string" model.

Compacts DNA X3.

Histone located in center with two wraps of DNA arround it.

Negative charge DNA attracted to pos of histone

Nucleosome Structure

"Beads on a string" form of chromatin

Core histones of nucleosome (200 pb of DNA)

Nuclease digests linker DNA which releases nucleosome. (11 nm).

Dissociation into octameric histone core,

146-nucleotide-pair double helix.

Histone core dissociated into H2A, H2B, H3 and H4 (X2 of all)

The 30 nm fiber

Nucleosome units made into 30 nm fiber. Compaction X7

Structure hard to determine, DNA may be altered when extracted

Requires Histone 1 (H1). Attaches to DNA to link histone cores together (compaction)

- creates zig-zag model

Final stage of condensation

Occurs at mitosis

DNA is compacted 10,000 X original DNA strand

Ends as 1400 nm in length compared to original 2 nm of naked DNA

What is Heterochromatin?

Type of compaction:

- Highly compact and transcriptionally inactive

- localized regions in nondividing cells (centromeres and telomeres)

What is Euchromatin?

Type of compaction:

- Less condensed, capable of gene transcription

- Located in most regions of non-dividing cells

(Turn into heterochromatin once divided)

Histone Tail

Histones not perfectly circular due to tail

Modification usually on N-terminus.


- Acetylation

- Phosphorylation

- Methylation

- Ubiquitination


Species that is diploid, Members of a pair of chromosomes

One from Mother

One from Father

Contain same genes but different alleles

Mitotic Cell Division

- Cell divides to produce two new cells, genetically identical

-Mother: Daughter + Daughter

The Cell Cycle of Mitosis

1. Interphase ( G1, S, G2)

2. Mitosis:

- Prophase

- Prometaphase

- Metaphase

- Anaphase

- Telophase

- Cytokinesis


Sorting process, each daughter cells gets correct number/ type of chromosomes

Mitotic Spindle

Responsible for organizing and sorting the chromosomes


Microtubule organizing center

-Come from mitotic spindle

What are the different microtubules?




Prophase and Prometaphase

Chromosomes condense

Nuclear envelope breaks down

Mitotic spindle forms

centrosomes move apart. go to two poles

Spindle fibers interact with sister chromatids

Kinetochores on sister attach to kinetochore on poles


Chromosomes are aligned along metaphase plate


Chromosomes segregate to opposite poles


Chromosomes at opposite poles. Membrane forms


Cell divides (Different for plants/ animals)

- Animals: Cleavage furrows

- Plants: Cell wall forms in center of cell. Expands toward edges until it divides


Sexual reproduction. Requires fertilization event. Two haploid gamates unite to create diploid cell called zygote.

-Meiosis: Process by which haploid cells are produced from cell originally diploid

Mitosis vs Meiosis

Mitosis: Chromosomes singly line up at the metaphase plate.

Meosis: Pair before lining up at the metaphase plate


Diploid cell: two haploid gamates unite


Homologous pairs of sister chromatids. lying side by side to form bivalent (tetrad).

Process called synapsis

Crossing Over

Physical exchange between homologous within a bivalent

Required for correct segregation of homologous in most species

Increases genetic variation

Chiasma: Cytologically observable site of crossover in bivalent

Haploid Dominant Species

Multicellular organism is haploid

Many fungi and protists

Diploid Dominant Species

Most animal species

Haploid gametes are a specialized type of cell

Name a few chromosomal mutations

Deletions: segments missing

Duplications: Section occurs 2 or more times in a row

Inversions: Self-explanatory

Translocations: One segment becomes attached to another chromosome


Alternation in number of particular chromosomes

Total number not an exact multiple of a set


Normal 2 copies of a chromosome plus a 3rd

2n + 1, Trisomy 21


Missing one of normal copies of a chromosome

2n - 1, XO