What is not true of homologous chromosomes?

Both chromosomes come from one parent

What is true of homologous chromosomes?

They contain the same amount of DNA and have the same genes along their length

How many homologous pairs does the parent cell of a diploid cell with 12 chromosomes have?

6

How many sister chromatids does the parent cell of a diploid cell with 12 chromosomes have?

24

How many chromosomes does the parent cell of a diploid cell with 12 chromosomes contain after interphase?

12

At which point in the parent cell of a diploid cell with 12 chromosomes does DNA replication occur?

S phase during inyerphase

Is interphase part of either mitosis or meiosis?

No

Homologous chromosomes pair occurs during

Meiosis 1

Homologouschromosomes separate each other during

Meiosis 1

Crossing over occurs during

Meiosis 1

Independent assortment occurs during

Meiosis 1

Sister chromatids separate from each other during

Mitosis and meiosis 2

Two processes that lead to genetic variation during meiosis are

Crossing over and independent assortment

Protists have prokaryotic or eukaryotic cells?

Eukaryotic

What structure is responsible for moving the chromosomes into a new arrangement?

Spindle fibers

How does the chromosomal content compare to the parent cell at G1 that you started with?

It is identical to the parent cell

Interphase in an Onion

Prophase in an Onion

Metaphase in an Onion

Anaphase in an Onion

Telophase in an Onion

Interphase

G1, G2, S phase (DNA Replication)

Prophase in Mitosis

Chromosomes condense, centrosomes radiate microtubules and migrate to opposite poles, microtubules attach to chromosomes

Metaphase in Mitosis

Chromosomes align in center of cell

Anaphase in Mitosis

Sister chromatids (which become individual chromosomes when the centromere splits) separate and travel to opposite poles

Telophase in Mitosis

Nuclear envelope re-forms and chromosomes decondense

Meiosis

The germ cells in humans give rise to gametes through this, and create genetically unique daughter cells

Mitosis

Body cells reproduce through this, and create genetically identical daughter cells, aesexual reproduction

Cytokinesis

The full split of the two new cells

Sexual Reproduction

Organisms produce haploid cells called gametes (egg or sperm), each parent contributes one set of chromosomes in their egg or sperm, haploid gametes fuse during fertilization

First Step in Prophase 1 of Meiosis 1

Chromosomes first become visible as thin threads, DNA replication is already complete

Second Step in Prophase 1 of Meiosis 1

Homologous chromosomes continue to condense and undergo synapsis (gene for gene pairing)

Third Step in Prophase 1 of Meiosis 1

Each pair of homologous chromosomes forms a bivalent, each chromosome consists of two sister chromatids

Fourth Step of Prophase 1 of Meiosis 1

The chromosomes continue to shorten and thicken and the chiasmata between non-sister chromatids become apparent (crossing over)

Fifth Step of Prophase 1 of Meiosis 1

The nuclear envelope begins to break down

Prophase 1 (later phase) of Meiosis 1

Chiasmata present, spindles attach to kinetochores on chrmosomes

Metaphase 1 of Meiosis 1

Homologous pairs line up in center of cell, with bivalents oriented randomly with respect to each other

Anaphase 1 of Meiosis 1

Homologous chromosomes separate, but sister chromatids do not separate

Telephase 1 of Meiosis 1

Daughter cells are ready to move into prophase 2

Meiosis 2

Same as mitosis, ends with 4 different combinations of chromosomes