Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Bio Day 15
Biology Day 15: Meiosis
| Term | Definition |
|---|---|
| Why sexual reproduction happens: | Evolutionary leap forward Each of the cells going to be reproduced |
| Recombination of genes: | both sides (both donors of DNA) change up their genes - take the genes in their bodies and mixes them up |
| Eukaryotic cells have the possibility of reproducing sexually - | their daughter cells can change their DNA (so every single daughter cell has unique DNA) |
| Asexual reproduction is fast and efficient - issue: | if anything appears that can attack the asexually reproducing colony - whole colony can be wiped out No genetic material |
| Homologous: | Chromosomes come in pairs - are coding for the same parts, the gene themselves are not identical, one from mom, one from dad (both code for color of eyes, but one is blue and one is brown) |
| Sex chromosomes: | are either X or Y (Y is if its missing a whole part of its chromosome) |
| X genes are: | full things (physical body parts), as long as there is a X gene the fetus can grow |
| Y genes are | fine - only to turn into a boy - if it is not there the fetus is fine All fetuses are female until the Y gene comes in |
| Gene: | a segment of DNA that codes for a trait |
| Allele: | version of a gene If it is not a sex chromosome it is an autosomal chromosome |
| Autosomal chromosome: | 22 numbered pairs of chromosomes found in humans, excluding the sex chromosomes (X and Y). 1-22, are involved in carrying genetic information for traits and conditions that are not related to sex determination. |
| Haploid: | 1 copy of each chromosome |
| Diploid: | 2 copies of each chromosome (of every gene) (1 copy from each biological parent) Our autosomal cells (everything outside of our sex cells) are diploid Our sex cells are haploid - need to join together to have a two copy human being |
| Meiosis is different from mitosis since: | in mitosis the sister chromatids are exact copies and are pulled apart so that they match while in meiosis everything is randomized In meiosis, the copies from mom and dad lineup with each other at first, meiosis happens twice |
| In meiosis 1, | the copies from mom goes to a different cell then where the dad copies go (everything doesn't split up in even cell (one could be all from mom) |
| In meiosis 2, | everything is randomly separated - however they line up in the metaphase plate is how they pull apart |
| In meiosis prophase is the most | important part: due to genetic recombination - important for sexual reproduction |
| In prophase 1 | mom and dad copied DNA line up to each other - they line up together and form Chiasmata (crossing over) - have created four fully unique chromosomes - there is a random combination of mom and dad - |
| Chiasmata: | (crossing over) they're going to touch each other, whatever touches is going to exchange (change their DNA/genetic recombination) - are fully interchanged - are held very tightly together |
| since the chromosomes do not cross over in the exact same spots, they are | completely different things - Each chromatid is now fully unique - they still code for the exact same gene, but the alleles are different |
| in Prophase 1 what happens: | chiasma is formed and chromosomes cross over |
| in Metaphase 1 what happens: | they randomly line up on the fake equator in a tetrad - two chromosomes line up on top of eachother |
| Tetrad: | a group set of four - the chromosome copy one from mom, the one from dad |
| in Anaphase 1 what happens: | the tetrads are separated and the homologs stay together - still has a diploid cell but no longer have 1 from mom and 1 from dad |
| telophase/cytokinesis: | cell divides |
| After telophase/cytokinesis | : mitosis basically happens again but with the only difference that each gene is not specifically from mom and dad and are randomly combined |
| In mitosis: | have 46 separate chromatids pulled to either side |
| In meiosis: | there are 23 pairs pulled to either side |
| In meiosis 2: | they separate into four separate cells and become haploid cells |
| Interphase: | uncondensed chromosome replicate in parent cell |
| Prophase 1: | spindle fibers start to show up, (not sister chromatids) homologous chromosomes, have the centromere and kinetochore, chiasmata forms and has the synapses - forms a tetrad |
| Early prophase 1: | chromosome condense, spindle apparatus forms, nuclear envelope begins to break down. Synapsis pairing of homologous chromosomes. |
| Late prophase 1: | chiasmata (cross over points) are visible. Nuclear envelope broken down. |
| Synapsis: | sister chromatids are held tightly together |
| Homologous chromosomes: | chromosomes are approximately the same size and have the same type of gene in the same location one from mom and one from dad |
| Metaphase 1: | movement of bivalents to metaphase plate is complete has 23 homologous tetrads together, forms diploid cells Four little X’s |
| Anaphase 1: | homologs move to the opposite poles of the spindle apparatus A full X are pulled on each side |
| Telophase 1: | homologs are at opposite poles; spindle apparatus disassembles |
| cytokinesis 1: | cell divides; chromosome number is reduced. chromosomes gather at the poles of the cells. |
| Part two of meiosis is: | mitosis |
| For all living things that undergo sexual reproduction, the male side: | makes four cells that are going to be used, the female makes 1 cell and the other three are basically tossed In humans they are called polar bodies - never turn into mature eggs |
| Prophase 2: | a new spindle apparatus reforms - around the chromosomes |
| Metaphase 2: | chromosomes are lined up at the middle of the spindle apparatus - metaphase plate |
| Anaphase 2: | sister chromatids separate, move to the opposite poles of the spindle apparatus |
| Telophase 2: | daughter chromosomes are at opposite poles; spindle apparatus disassembles |
| Cytokinesis 2: | 2l divides; chromosome number is unchanged |
| Cohesin: | proteins that form a complex that seals sister chromatids together at their centromeres until anaphase II of meiosis |
| mitosis differences | 1 cell division - Has the same number of chromosomes in daughter cells compared to parent cells - Is doubled: daughter cells are diploid - Are identical |
| Mitosis role in organism life: | : asexual reproduction in some eukaryotes; cell division for growth, replacement of cells, and wound healing |
| Meiosis differences: | 2 cell divisions - Has half of the number of chromosomes in daughter cells compared to parent cells - Is quadrupled: daughter cells are haploid Chiasmata can happen multiple times on same chromosome |
| Meiosis role in organism life: | halving of chromosome number in cells that will produce gametes |
| Meiosis happens: | to get genetic variation - Are not identical - causes extreme genetic variation Why eukaryotes has more specie diversity than prokaryotes |
| Sickle Cell anemia and cystic fibrosis: | is dependent on dominant or recessive gene - Common allele means you don't have it, no name means you have it - Carriers of sickle cell anemia are immune to malaria and the flu |
| Dominant gene: | regardless of how many copies you have, you’ll have it - (having brown eyes is dominant to blue eyes) - a gene variant that expresses itself more strongly than other versions of the same gene, even when paired with a recessive allele. |
| Recessive gene: | you need two copies to get it - a gene whose effect is masked by the presence of a dominant gene in the same pair of alleles |
| Independent assortment: | alleles separate without caring what other genes are doing - not 100% true, such as the gene for red hair that takes freckles with it |
| Recombination: | alleles from mom and dad are mixed up then separated in chromatids - everything is mixed up, a good thing - 100% true |
| Random fertilization: | there is no specific choice for one sperm vs another - also not 100% true, the egg will be able to pick which sperm is chosen |
| When meiosis goes wrong: | is horrible due to pulling chromosomes apart - causes aneuploidy, down syndrome, and no Y chromosome - baby only survives in chromosome 21 & 13 and without a Y chromosome |
| Aneuploidy: | an incorrect number of genes - most common cause of spontaneous abortions (miscarriages) (If there is no X gene it will cause a miscarriage) An issue like aneuploidy causes 20-40% of all pregnancies |
| Chromosome 21 & 13 can cause down syndrome: | when we are creating daughter cells and are separating 1 of the chromosomes don’t go to other side, 1 will miss a cell while the other has 2 |
| Has an extra copy, in down syndrome it changes multiple things like | : brain features, height, facial features, etc Could not have a Y chromosome (will be XX and the other one is Xnothing) - not really harmful |
| Sexual life cycles: | involve a dynamic interplay of meiosis, fertilization, and the alternation between haploid and diploid stages in an organism's life |
| Haploid life cycle: | have a single set of genes Ex plants, and lesser animals |
| Diploid life cycle: | create gametes that fertilize (are only sex cells that turn into one thing) |
| Alternation of generations: | half of the time they are haploid or diploid have both haploid and diploid multicellular organisms as part of their life cycle. Ex: fern plants, are a haploid being - under the fern, an inch height, are a diploid being |
| Gametophytes: | a multicellular haploid life-cycle stage that produces gametes The haploid multicellular plants that produce gametes from specialized cells. |
| Sporophyte: | forms after the zygote undergoes many rounds of mitosis and gives rise to a diploid multicellular plant. Specialized cells of the sporophyte will undergo meiosis and produce haploid spores. - will subsequently develop into the gametophytes |
| Spore: | haploid cell that can produce a haploid multicellular organism or can fuse with another spore to form a diploid cell |
| Bivalent chromatids: | having four chromatids |
| Gametes: | Sexual reproduction requires the union of these two specialized cells, each of which contains one set of chromosomes. |
| Zygote: | fertilized egg that contains two sets of chromosomes. - formed by the union of 2 gametes |
| Somatic cell: | all the cells of a multicellular organism except the gametes or reproductive cells |
| Meiosis G1 phase (the “first gap phase”): | is focused on cell growth. |
| Meiosis S phase—the second phase of interphase: | the cell copies or replicates the DNA of the chromosomes. - Each chromosome is replicated to produce 2 identical copies—sister chromatids that are held together at the centromere by cohesin proteins, - hold chromatids together - anaphase II. |
| meiosis G2 phase (the “second gap phase”: | the cell undergoes the final preparations for meiosis. |
| Interkinesis: | (also, interphase II) brief period of rest between meiosis I and meiosis II |
| synaptonemal complex: | lattice of proteins between the homologous chromosomes, supports the exchange of chromosomal segments between homologous non sister chromatids—a process called crossing over |
| reduction division | : nuclear division that produces daughter nuclei each having one-half as many chromosome sets as the parental nucleus; meiosis I is a reduction division |
| Metaphase plate: | —roughly in the midline of the cell, |
| Life cycles: | the sequence of events in the development of an organism and the production of cells that produce offspring |
| Fertilization: | union of two haploid cells from two individual organisms the joining of two haploid gametes, restores the diploid condition. |
| Germ cells: | specialized diploid cells that are produced within the gonads (such as the testes and ovaries). |
| Mitosis is important for | growth, and for repair to damage, and to replace worn out cells - makes body and skin cells |
| Nondisjunction: | when a cell receives too many or too few chromosomes in the separation |
| Meiosis is a reduction revision because: | the starting cell has 46 chromosomes and the ending cells (gametes, sperm and egg cells) has 23 chromosomes |
Created by:
Katepop10