Meiosis

What is meiosis

Form of eukaryotic cell division that is a process that produces haploid gametes

What does the male produce

Four viable sperm

How do starfish reproduce

Fragmentation

Where does meiosis take place

Gametes of an organism

Identify the different types of sexual life cycles

Haploid, diploid, life cycles and alternation of generations

What does the female produce

One viable egg and three nonfunctioning polar bodies

What is the process that produces haploid gametes

Sexual reproduction

Why does interphase not occur in meiosis II

1) Because DNA was already replicated 2) normal cell metabolism and activity 3) protein synthesis (proteins are made)

Explain the Diploid life cycle

1) organisms spend majority of their lives as diploid adults 2) when they are ready to reproduce, they undergo meiosis and produce haploid gametes 3) then the gametes unite in fertilization and form a diploid zygote 4) the zygote develops into a diploid adult that repeats the life cycle

Explain the Haploid life cycle

1) simplest life cycle 2) found in many single called organisms 3) organisms spend majority of their life as haploid gametes 4) quickly undergoes meiosis to produce more haploid gametes that repeat the life cycle

How many chromosomes can an egg/ sperm have

23

How many chromosomes do people have

46

how many chromosomes does gametes have

46

Compare and contrast asexual and sexual reproduction

Asexual reproduction involves one parent and produces offspring that are genetically identical to each other and to the parent. Sexual reproduction involves two parents and produces an offspring that are genetically unique.

What happens at the end of meiosis

At the end of meiosis the individual gamete cell divided into four cells

When does meiosis I begin

Begins after DNA replicates during interphase

What are the three types of asexual reproduction

Binary fission, fragmentation, and budding

How does yeast produce

Budding

Explain why does sexual reproduction result in a genetically unique off spring

Due to independent assortment and crossing-over during meiosis and random Union of gametes during fertilization

What is crossing over

Exchange of genetic material between non-sister chromatids of homologous chromosomes which results in the new combinations of genes on each chromosome

Is asexual reproduction fast or slow

Fast

What does asexual reproduction involve

Involves one parent and produces offspring that are genetically identical to each other and to the parent. It involves two parents and produces offspring that are genetically unique.

What does meiosis ensure

Meiosis ensures that all living organisms will maintain both Genetic diversity and Genetic Integrity

Difference between meiosis and mitosis

Meiosis:

Do the cells turn into gametes at the end of meiosis ?

No

What doe sexual reproduction result in

Offspring that are genetically unique

What are the organisms that have the life cycle with alternating generations

Plants, algae, and some protists

Explain the phases of meiosis I

Prophase I: The nuclear envelope begins to break down, and the chromosomes condense. Centrioles start moving to opposite poles of the cell, and a spindle begins to form. Importantly, homologous chromosomes pair up, which is unique to prophase I. In prophase of mitosis and meiosis II, homologous chromosomes do not form pairs in this way. During prophase I, crossing-over occurs (see below). 2. Metaphase I: Spindle fibers attach to the paired homologous chromosomes. The paired chromosomes line up along the equator of the cell. This occurs only in metaphase I. In metaphase of mitosis and meiosis II, it is sister chromatids that line up along the equator of the cell. 3. Anaphase I: Spindle fibers shorten, and the chromosomes of each homologous pair start to separate from each other. One chromosome of each pair moves toward one pole of the cell, and the other chromosome moves toward the opposite pole. 4. Telophase I and Cytokinesis: The spindle breaks down, and new nuclear membranes form. The cytoplasm of the cell divides, and two haploid daughter cells result. The daughter cells each have a random assortment of chromosomes, with one from each homologous pair. Both daughter cells go on to meiosis II.

Explain the phases of meiosis II

Prophase II: The nuclear envelope breaks down and the spindle begins to form in each haploid daughter cell from meiosis I. The centrioles also start to separate. 2. Metaphase II: Spindle fibers line up the sister chromatids of each chromosome along the equator of the cell. 3. Anaphase II: Sister chromatids separate and move to opposite poles. 4. Telophase II and Cytokinesis: The spindle breaks down, and new nuclear membranes form. The cytoplasm of each cell divides, and four haploid cells result. Each cell has a unique combination of chromosomes.

What happens in interphase in meiosis

Protein photosynthesis; DNA replication; normal cell metabolism and activity

What is a gamete

Reproductive cells

What is reproduction

The process by which organisms give rise to offspring

What is fertilization

The process where two gametes unite

What is a life cycle

The sequence of stages an organism goes through one generation to the next.

What happens to organisms that have a lifecycle its alternating generations

They switch back and forth between diploid and haploid stages

Why does sexual reproduction lead to variation in an offspring

This variation is due to independent assortment and crossing-over during meiosis and random Union of gametes during fertilization.

What does sexual reproduction have the potential to produce

Tremendous variation in offspring

True of false: Organisms that reproduce sexually can have different types of life cycles, such as haploid or diploid life cycles

True

How many parents does sexual reproduction have

Two

During meiosis gamete (sex) cells what does it undergo

Undergoes "cell division", maintains DNA, but reduces the chromosome amount to 23

When does budding occur

When a parent cell forms a bubble-like bud. The bud stays attached to the parent cell while it grows and develops. When the bud fully develops it breaks away from the parent cell and forms a new organism.

When does binary fission occur

When a parent cell splits into two identical daughter cells of the same size

When does fragmentation occurs

When a parent organism breaks into fragments, or pieces, and each fragment develops into a new organism.

Define zygote and how many chromosomes does it have

Zygote-fertilized cell #- 46

What is meiosis

a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell.

What is asexual reproduction

a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only

What is cell division

the division of a cell into two daughter cells with the same genetic material.

What is oogenesis

the production or development of an ovum.

What is spermatogenesis

the production or development of mature spermatozoa.