idk Untitled Flashcards Set

Mitosis- cellular division

At the end- 2 identical daughter cells

Only get clones- identical twins

meiosis- chromosome reduction

chromosones- 46 chromosones

23 from mom 23 from dad- baby then when baby is grown creates chromosones

Why people look related

Somatic cells- body cells(not sex cells) except gametes. Mitosis

Gametes- reproductive cells(sex cells) meiosis

Cell cycle

Part 1- interphase- 3 diff parts- (the nucleus is still there/ centrioles/ plasma membrane/ nuclear envelope)

Part 2- mitosis- nucleus divides

Part 3- cytokinesis- entire cell divides

g=growth

Mitosis = nuclear division

Mitosis is used for growth and repair in organisms.

There are 4 stages of Mitosis:

Prophase

Metaphase

Anaphase

Telophase.

Prophase

The nuclear membrane is broken down

Chromatin condenses and is visible as chromosomes

Spindle fiber forms

Anaphase

Sister chromatids separate and move to opposite sides of the cell.

Metaphase

Chromosomes line up in the middle of the cells.

Telophase

Spindle fibers disappear.

Nuclear membrane reforms.

Chromosomes begin to uncoil and return to chromatin form.

CROSSING OVER

Homologous chromosomes are a pair of chromosomes that have different versions of

the same genes

Crossing over is where the DNA is exchanged between the homologous chromosomes making

them genetically different

Homologous

Chromosome

chromosomes

crossover

Recombinant

chromatids

IT ONLY HAPPENS ONCE DURING PROPHASE ONE OF MEOSIS ONE

METAPHASE 1

Shortest phase

Tetrads align on the equator.

Independent assortment occurs - chromosomes separate randomly causing GENETIC

RECOMBINATION

ANAPHASE I

Homologous chromosomes separate and move towards the poles.

Sister chromatids remain attached at their centromeres.

TELOPHASE I

Each pole now has haploid (1n) set of chromosomes.

Cytokinesis occurs and two haploid daughter cells are formed.

METAPHASE II

•Same as Metaphase in mitosis

Chromosomes (not homologs) line up at equator

ANAPHASE II

Same as Anaphase in mitosis

SISTER CHROMATIDS
separate

TELOPHASE II

Same as Telophase in mitosis.

Nuclei and Nucleoli reform, spindle disappears

CYTOKINESIS occurs.

Remember: FOUR HAPLOID
DAUGHTER cells are produced.

Called GAMETES (eggs and sperm)

In Sperm cell fertilizes In egg to form 2n zygote