Mitosis

what are some pros of internal fertilization

higher chance of success

what is internal fertilization

it occurs inside organisms and it occurs in most organisms that reproduce sexually

anaphase II

Centromeres divides. Sister chromatids move to the opposite poles of the cells.

How is DNA organized during interphase?

Chromosomes are tightly packed coiled strands

Chromatin

Clusters of DNA, RNA, and proteins in the nucleus of a cell

Interphase

Longest part of cell cycle, when cells grow, develop and duplicate DNA and organelles to prepare for mitosis.

Somatic cell

anything besides your gamies (nerve cells) like nerve cells, ect.

Telophase

last stage of mitosis in which nucleoli reappear. Two new nuclear membranes begin to form, but the cell has not yet completely divided.

When does DNA replicate?

DNA replication occurs in the S phase of the cell cycle.

S Phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

Is there an exchange of genetic material during sexual reproduction?

Yes (Meiosis phase)

what is the use of mitosis in unicellular cells

makes more of the species

Where in the cell is DNA found?

nucleus

Is there an exchange of genetic material?

No

Cytokinesis is the division of the __________.

cytoplasm

What is the function of DNA?

genetic instructions for the development and function of living things.

Humans are diploid and our gametes are _________.

haploid

Homologous chromosomes pair during

prophase I

Chromatin

unpackaged unwound DNA in the nucleus of a cell

what are some pros of internal development

- protection of the young - gets all the nutrients inside the mother

Dipliods

-Diploid cells contain two complete sets (2n) of chromosomes. -Diploid cells reproduce by mitosis making daughter cells that are exact replicas. - example: somatic cells -paired

Spermatogenesis (creation of sperm)

-sperm are awful survivors - higher amount of them more of a chance of fertilization - starts at puberty (around 13) -ends at death -billions of sperm per lifetime

Prophase

-the chromosomes coil up and become visible while the nuclear envelope disappears. -Sister chromatids are present. A centriole forms at each pole and spindle fibers made of microtubules grow out of it. -Short microtubules stick out from the centriole in a star shape known as an aster.

Telophase

1. A new nuclear membrane is forming around chromosomes. 2. The cytoplasm is being divided. 3. The chromosomes unwind and become invisible. 4. The cell plate is completed (plants) 5. The reverse of prophase 6. Spindle fibers break down 7. Two identical nuclei form 8. Division of cleavage furrow appears

Prophase

1. Nuclear membrane begins to fade from view. 2. The spindle begins to form 3. Copied DNA condenses into chromosomes 4. The nucleolus disappears, and the nuclear membrane breaks down

Metaphase

1. Second phase of mitosis, during which the chromosomes line up across the center of the cell. 2. Centromeres of duplicated chromosomes are aligned at plate. Fully formed spindle attach to the sister chromatids from opposite poles

Anaphase

1. The sister chromatids move apart. 2. The chromosomes move towards the poles of the cell. 3. Cell elongates and grows larger

How many cells are formed during sexual reproduction?

4 (Haploid) cells

How many chromosomes do humans have?

46

Chromatids

Bodies of tightly coiled chromatin; visible during cell division. Two chromatids bound at a centromere make a CHROMOSOME.

What happens during the M phase? How long does the cell spend in this phase?

Cell division

Interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases. (Period of normal growth and maintenance. (3 stages)

What is a chromosome?

DNA and (histone) protein arranged in thick filaments visible when cell divides in mitosis and meiosis.

Chromosomes

DNA that is coiled together and condensed into small packages (like DNA suitcases) (each has 23 from mom, 23 from dad). Consists of 2 "sister" chromatids bound at a centromere.

Chromosome

DNA-containing structure that carries genetic material from one generation to another

G2

Final preparation phase. Cell checks for DNA errors and begins to form centrosomes. (Prepares for Mitosis)

G1

In interphase - cell grows rapidly, builds new organelles; also performs regular cell functions

At which stage of mitosis are chromosomes lined up at the equator?

Metaphase

Crossing over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Sister chromatids are formed during __________.

Prophase

Spindle fibers

Special strands of microtubules which grow out of the centrioles, connect to chromosomes at the centromeres, and pull them apart during (anaphase) of mitosis.

S phase

The "synthesis" phase of the cell cycle; the portion of interphase during which DNA is replicated. (doubles each chromosomes)

What is crossing over? During which phase of meiosis does it take place?

The exchange of corresponding segments between non sister chromatids of homologous chromosomes and occurs during prophase of meiosis.

Cell cycle

The stages that take place between the time a eukaryotic cell divides and the time the daughter cells divide. (stages of growth, preparation, and division (Interphase and Mitosis)

What is chromatin?

Thin DNA filaments seen when the cell is not dividing.

What is sexual reproduction?

This is when two organisms exchange sperm and an ovary to fertilize an egg in order to produce a new organism for genetic diversity.

What are homologous chromosomes?

Two chromosomes that belong to a pair. Also called homologs. 23 from each parent. The pairs of chromosomes from that pair up are called homologous chromosomes. A to A and B to B for example.

what is internal development

fetus develops inside mother

what is synapsis.

pairing of homologous chromosomes during the meiosis phase of cell division

what is the use of mitosis multicellular cells

repair and replace dead or old cells (regeneration)

Metaphase

second stage of mitosis in which motor protons pull sister chromatids to the cell's equator

Sister Chromatid

structure that contains identical DNA copies and is formed during DNA replication

G Phase

the cell grows

Cytokinesis

third main stage of the cell cycle, during which the cell's cytoplasm divides, creating a new cell

Centromere (twin centriole pairs)

cell structure that joins two sister chromatids

Telophase

-Chromosomes become indistinct -Daughter cells are forming -Once the chromatids have reached the opposite sides the spindle fibers disappear -The chromosomes unravel -nuclear envelope reappears on the two new nuclei

Hapliods

-Haploid cells have half the number of chromosomes (n) -Example Gametes -Not paired

oogenis

-takes place in the ovaries -at birth females have 500,000 potential eggs - at prophase 1 eggs are paused -puberty (12-13) females have 250,000 potential eggs - a 1 ootid matures every month -this stops at menopause (mid 50 's) -females will only have 500 mature ootids -eggs are better survivors then sperm

Metaphase

1. The chromosomes are lined up located in the middle at the equator of the cell.

Cytokinesis

1.Third main stage of the cell cycle, during which the cell's cytoplasm divides, creating a new cell. 2. The cytoplasm forms a cleavage furrow at the equator to split the cytoplasm. (In plants a cell plate forms at the equator). 3. Part of cell cycle that is the shortest, after mitosis is complete.

How many cells are formed during asexual reproduction?

2 (diploid) cells

How many chromosomes do the daughter cells have at the end of meiosis?

23

What is asexual reproduction?

Reproduces cells, growth and maintenance but doesn't involve fertilization of an egg. (Mitosis)

What does cell reproduction accomplish?

Replaces damaged or lost cells, growth, reproduction and increases genetic diversity.

G2 Phase

The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.

Anaphase

Third phase of mitosis in which sister chromatids are pulled to opposite sides of the cell

Mitosis is the division of the ___________.

eukaryotic cells that occurs when a parent cell divides to produce two identical daughter cells.

Prophase

first stage of mitosis, during which the cell's chromatin condenses into chromosomes

Interphase

first stage of the cell cycle, during which a cell grows, matures, and replicates its DNA

Centromere

holds sister chromatids together.

what is a tetrad

homologous pair formed by synapsis.

Anaphase

third stage of mitosis in which sister chromatids are pulled apart and microtubules, along with motor proteins, move the chromosomes to opposite poles of the cell