Bio Cell Divison 12

Front 1

What is mitosis

Back 1

Reproduction of body cells, or somatic cells. In mitosis, exact copy of the parent cell is made. occurs in all cells except 'sex'cells

Front 2

What is meiosis

Back 2

Reproduction of sex cells, or gametes

Front 3

What is the main molecule responsible for

storing instructions and is the 'recipe' for

the human body?

Back 3

DNA

Front 4

What is replication?

Back 4

During cell division, these instructions must be

copied and passed on to the new cells. This is accomplished through the process of replication.

Front 5

What does each cell in a body have?

Back 5

A complete set of DNA

Front 6

What form is DNA in for most of the time?

Back 6

chromatin..., long thin, strands of DNA.

During cell division, these strands will coil up forming shorter, thicker structures called chromosomes.

Front 7

How do chromosomes start out?

Back 7

The chromosome starts out single stranded but during replication it forms 2 chromatids called

sister chromatids joined together by a

centromere.

Front 8

How many chromosomes in a mosquito, pea plant, sunflower, dog, and human?

Back 8

a mosquito has 6 chromosomesa pea plant has 14

a sunflower, 34

a human being, 46

and a dog, 78.

Front 9

What is a gene and what does it contain?

Back 9

A gene is a section of a chromosome that controls a specific characteristic. Carries instructions to build a protein

Front 10

What is meiosis - detail

Back 10

­ reproduction of sex cells the goal is not to create an exact copy of the parent cell's DNA, but a half copy.

Front 11

What is a diploid

Back 11

diploid (2n) = the number of chromosomes in a somatic cell

Front 12

what is a haploid

Back 12

haploid (n) = the number of chromosomes in a gamete

Front 13

What the G1 phase

Back 13

G1 phase: rapid growthand metabolism

Front 14

What is the S phase

Back 14

S phase: DNA synthesisand replication

Front 15

What is the G2 phase

Back 15

G2 phase: centriolesreplicate; cell preparesfor division

Front 16

What is prophase?

Back 16

The nucleolus fades and chromatin condenses into chromosomes.

• Centrioles migrate to opposite ends of the cell

and microtubules (spindle fibers) form between

them.

Front 17

What is metaphase?

Back 17

• Spindle fibers attach to the centromeres

• the chromosomes are lined up in the middle

of the cell. There is a separate spindle fiber for each

chromosome.

Front 18

What is anaphase?

Back 18

Spindle fibers shorten

• the centromeres separate and the

chromosomes are pulled apart sending 1

chromatid to each end of the cell. (end of cell =

pole)

Front 19

What is telophase?

Back 19

• The chromatids arrive at the poles

• the spindle fibers disappear

•a nuclear membrane forms around each group of chromatids

Front 20

What is cytokineses

Back 20

The separation of the cytoplasm and the formation of 2 new daughter cells.

Front 21

What is meiosis?

Back 21

is the cell division that occurs in reproductive cells to produce gametes (sperm and ovum).

Front 22

What is spermatogenesis and oogenesis?

Back 22

In a process called spermatogenesis, 4 sperm cells (spermatozoa) are made (males)and in a process called

oogenesis, 1 egg cell (ovum) is made (female)

Front 23

Why only one EGG (ovum) produced not 4?

Back 23

During Meiosis I, the cytoplasm is not divided equally to the two daughter cells. Thus only 1

viable cell result. The other cell is called the

polar body. The 1 viable cell undergoes Meiosis II and again the cytoplasm is unequally divided so only 1

viable cell (ovum or egg) is produced. The purpose of the unequal division is to

provide the 1 viable egg with enough

nutrients to support the developing zygote

after fertilization.

Front 24

What is Meiosis I and II?

Back 24

Meiosis I : the number of chromosomes is divided in half, creating two haploid cells.• Meiosis II: (similar to mitosis) results in two more cells, (for a total of four) that are all haploid

Front 25

What is interphase in meiosis?

Back 25

Interphase is the same in reproductive cells as in body cells.

Thecell grows and prepares for division. Before meiosis begins, the chromosomes replicate

forming Homologous chromosomes

Front 26

What is prophase I?

Back 26

Homologous chromosomes (ie: the pairs carrying the same genes) pair up. During this process, crossing over of genes may occur, where sections of the chromosomes are exchanged. This allows for genetic variation.

Front 27

What is metaphase I?

Back 27

Homologous chromosomes align at the equator of the cell. The centrioles migrate to the poles,

and the spindle forms.

Front 28

What is a tetrad?

Back 28

When two homologous chromosomes are aligned at the equator, they are called a tetrad.

Front 29

What is independent assortment?

Back 29

The homologous pairs are randomly oriented along the equator. This is called independent assortment and it allows for genetic variation.

Front 30

What is anaphase I?

Back 30

The chromosomes are drawn to opposite poles. However, the sister chromatids do not separate.

instead, one whole chromosome from each

homologous pair is drawn to each pole.

Front 31

Whats telophase I?

Back 31

Chromosomes reach the poles of the cell.

Front 32

Prophase II?

Back 32

The haploid cells from Meiosis I prepare to

divide. Centrioles replicate.

Front 33

Metaphase II?

Back 33

Centrioles migrate to the poles, the spindle

forms, and the chromosomes align at equator.

Front 34

Anaphase II?

Back 34

Sister chromatids separate at the centromere,

and are drawn along the spindle to the poles.

Front 35

Telophase II?

Back 35

Chromatids reach the poles of the cells.

Front 36

Cytokinesis II?

Back 36

The cell divides. The end result is four daughter

cells, all of which are haploid.