Meiosis pop quiz study guide

tetrad

4 chromatid structure formed during prophase I to allow for crossing over

gene

A part of a chromosome that encodes an RNA or protein product in its DNA sequence. Unit of hereditary information.

somatic cells

A somatic cell is any cell of the body except sperm and egg cells. Somatic cells are diploid, meaning that they contain two sets of chromosomes, one inherited from each parent.

difference between: Autosome and sex chromosome

Autosomal chromosomes are chromosomes present in both males and females. Sex chromosomes are unique males and females. Females have XX sex chromosomes and males have XY sex chrosomes.

difference between: Autosomes and sex chromosomes

Autosomal chromosomes are chromosomes present in both males and females. Sex chromosomes are unique males and females. Females have XX sex chromosomes and males have XY sex chrosomes.

homologous chromosomes

Chromosomes with the same length, shape and genes. In sexual reproducers, one member of a homologous pair is paternal and the other is maternal.

Understand the factors that cause genetic variation associated with meiosis.

Crossing over during prophase I - exchange of genetic material between non-sister chromatids Random alignment of chromosomes at metaphase I - spindle fiber contact between paternal and maternal chromosomes is random Which sperm fertilizes the egg is random

difference between: crossing over and random alignment of chromosomes

Crossing over is when non-sister chromatids exchange genetic information during prophase. Random alignment is the increased chance of diversity resulting from what homolog the spindle fibers attach to during metaphase 1 being random

nonsister chromatids

Different chromatids (maternal and paternal) of the same chromosome.

primary spermatocyte

Diploid cell with duplicated DNA that gives rise to the secondary spermatocytes

alleles

Forms of a gene with slightly different DNA sequences; made encode slightly different versions of the gene's product .

fertilization

Fusion of two gametes to form a zygote; part of sexual reproduction

difference between: Gametes and somatic cells

Gametes are haploid sex cells and somatic cells are diploid body cells

secondary oocyte

Haploid cell resulting from the division of the primary oocyte. It has more cytoplasm then the polar bodies. Will give rise to the ovum.

Spermatids

Haploid cells resulting from secondary spermatocytes -- gives rise to the spermatozoa

difference between: Haploid and diploid

Hapoid cells (n) are cells that have half of the normal number of chromosomes (so 23 chromosomes in humans). Diploid cells have the formal number of chromosomes (46 in humans.)

haploid number

Having one of each type of chromosome characteristic of the species.

meiosis I

Homologous chromosomes separate

State the number of chromosomes and homologous pairs of chromosomes found in the somatic cells of humans

Humans have 23 pairs of chromosomes including 22 homologous pairs.

Identify the number of sex chromosomes and autosomes present in humans

Humans have 44 autosomal chromososomes and 2 sex chromosomes.

germ cells

Immature reproductive cell that gives rise to haploid gametes when it divides.

difference between: Meiosis I and Meiosis II

In meiosis 1 homologous chromosomes are separated. In meiosis 2 sister chromatids are separated.

ovum

Mature animal egg

gametes

Mature, haploid reproductive cell; e.g. egg or sperm

Understand the effect that meiosis has on chromosome number.

Meiosis halves the chromosome number - from diploid to haploid

meiosis

Nuclear division process that halves the chromosomes number. Basis of sexual reproduction

difference between: Oogenesis and spermatogenesis

Oogenesis is the formation of egg cells (female sex cells) from germ cells and spermatogenesis is the formation of sperm cells (male sex cells) from germ cells

Explain the relationship between homologous pairs of chromosomes and how they're inherited

Organisms get one homologous chromosome from each parent.

Describe the events that occur in each meiotic phase.

Prophase 1 - homologous chromosomes pair together in tetrads and crossing over occurs, spindle fibers attach to centromeres and nuclear membrane breaks up Metaphase 1 - Homologous chromosomes line up in the middle of the cell (random assortment comes into play here) Anaphase 1 - homologs are pulled away from each other Telophase 1 - 2 haploid nuclei with duplicated chromosomes formed cytokinesis (NO DNA REPLICATION) Prophase 2 - spindle fibers attach to centromeres and nuclear membrane breaks up Metaphase 2 - duplicated chromosomes line up in the center of the cell Anaphase 2 - sister chromatids are pulled apart Telophase 2 - four haploid not identical daughter cell are formed

sexual reproduction

Reproduction mode by which offspring arise from two parents and inherit genes from both.

asexual reproduction

Reproduction mode of eukaryotes by which offspring arise from a single parent only.

Compare mitosis and meiosis; cite similarities and differences.

Similarities - nuclei divide, followed by cytokinesis, Differences - Meiosis produces haploid cells and mitosis produces diploid cells, meiosis has 2 cycles and mitosis only has one, meiosis produces sex cells and mitsois produces body cells

difference between: Non sister chromatids and sister chromatids

Sister chromatids carry the exact same genetic material and are connected by the centromere. Non-sister chromatids do not have the same alleles and/or genetic material and are not connected at the centromere.

Understand the factors that cause cells to reproduce.

Surface area to volume ratio reproduction growth and repair Meiosis happens because organisms need sex cells for sexual reproduction.

prophase I

The chromosomes condense, and the nuclear envelope breaks down. crossing-over occurs.

oogenesis

The production and growth of the ova (egg cells) in the animal ovary.

spermatogenesis

The series of cell divisions in the testis that results in the production of spermatozoa. Produce spermatocytes them spermatids then spermatozoa.

sister chromatids

The two attached DNA molecules of a duplicated eukaryotic chromosome; attaches at the centromere

polar body

Tiny haploid cell produced by unequal cytoplasmic division during egg production

random alignment

When members of a homologous pair line up randomly with respect to maternal or paternal origin during metaphase I of meiosis, thus increasing the genetic diversity of offspring.

Describe the formation of a diploid zygote (fertilization process)

When sperm and egg meet a diploid zygote is formed. The nuclei of the sperm and egg fuse as the random chance of sperm fertilizing egg increases chance of variation in offspring.

chromosome

a structure that consists of DNA and associated proteins; carries part or all of a cell's genetic information.

clone

an organism or cell, or a group of organism or cells, produced asexually from one ancestor or stock, to which they are genetically identical.

Contrast asexual and sexual types of reproduction that occur on the cellular and multicellular organism levels.

asexual types of reproduction - mitosis, binary fission sexual - fertilization (with cells created by meiosis)

paternal chromosomes

chromosomes from a father

maternal chromosomes

chromosomes from a mother

difference between: X and Y chromosomes

females have XX sex chromsomes and males have XY

synapsis

formation of tetrads

crossing over

process by which homologous chromosomes exchange corresponding segments of DNA during prophase I of meiosis.

Primary oocyte

prospective egg cell w duplicated chromosomes -- diploid

meiosis II

sister chromatids separate

sperm

spermatozoa; male gamete