Term
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Definition
- the division of a diploid (2N) parent cell to form haploid (N) daughter cells
- used for formation of gametes
- Meiosis 1: REDUCTION DIVISION
- the second division is just like mitosis |
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Term
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Definition
- homologous pairs of chromosomes come together
- Anaphase I pairs of chromosomes separate (centromeres do no divide)
- second division is required to separate the chromatids |
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Term
| Homologous pairs of chromosomes have the same... |
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Definition
- Length
- Centromere position
- Genes along their length
- each has a maternal homolog and a paternal homolog |
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Term
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Definition
· Same as interphase in mitosis
· DNA (chromosomes) replication takes place
- Organelle replication takes place
· A store of energy (ATP) builds up
· Centrioles replicate |
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Term
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Definition
· Same as prophase in mitosis, with additions
· Centrioles move apart and spindle starts to form
· Nuclear membrane dissolves
· Chromosomes condense and appear as two chromatids joined by a centromere
· ALSO, homologous chromosomes come together in pairs
· Only occurs in meiosis 1
· Crossing over and recombination occurs at this stage |
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Term
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Definition
· Same as metaphase in mitosis except that chromosomes line up along the equator IN PAIRS
· Spindle is fully formed
· Chromosomes line up along the equator of the cell and attach to spindle fibres by their centromeres |
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Term
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Definition
· Same as anaphase in mitosis: except that:
· Chromatids remain joined at their centromeres
· Instead, homologous pairs separate with one homolog from each pair going to each pole
· A phenomenon known as independent assortment is observed at this stage
· Spindle fibres contract
· Centromeres split and sister chromatids are pulled apart - towards opposite poles of the cell
· It is at this stage that chromatids become chromosomes in their own right |
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Term
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Definition
· Same as in mitosis: except that:
· Chromosomes are still "double structure", i.e. 2 chromatids joined by a centromere, STILL STUCK TOGETHER
· The second division of meiosis is required inn order to separate the chromatids
· The second division of meiosis is basically the same as mitosis
· Two new groups of chromosomes have formed
· New nuclear membranes form
· Cytokinesis occurs
· In a plant cell, a cell plate forms (new cell wall grows from the inside out)
· Plant cells do not have centrioles (but still have spindles |
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Term
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Definition
• Centrioles move apart and spindle starts to form
• Nuclear membrane dissolves
• Chromosomes condense and appear as two chromatids joined by a centromere |
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Term
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Definition
• Spindle is fully-formed
• Chromosomes line up along the equator of the cell and attach to spindle fibres by their centromeres |
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Term
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Definition
• Spindle fibres contract
• Centromeres split and sister chromatids are pulled apart - towards opposite poles of the cell
• It is at this stage that chromatids become chromosomes in their own right |
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Term
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Definition
• Two new groups of chromosomes have formed
• New nuclear membranes form
• Cytokinesis occurs
• In a plant cell, a cell plate forms (new cell wall grows from the inside out)
• Plant cells do not have centrioles (but still have spindles) |
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Term
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Definition
- growth
- maintenance
- repair
- asexual reproduction (budding, hydra)
- cytokinesis - the physical division of the cell
- no nucleus - binary fission |
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Term
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Definition
· DNA (chromosomes) replication takes place
- Organelle replication takes place
· A store of energy (ATP) builds up
· Centrioles replicate |
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Term
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Definition
• Centrioles move apart and spindle starts to form
• Nuclear membrane dissolves
• Chromosomes condense and appear as two chromatids joined by a centromere |
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Term
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Definition
• Spindle is fully-formed
• Chromosomes line up along the equator of the cell and attach to spindle fibres by their centromeres |
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Term
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Definition
• Spindle fibres contract
• Centromeres split and sister chromatids are pulled apart - towards opposite poles of the cell
• It is at this stage that chromatids become chromosomes in their own right |
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Term
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Definition
• Two new groups of chromosomes have formed
• New nuclear membranes form
• Cytokinesis occurs
• In a plant cell, a cell plate forms (new cell wall grows from the inside out)
• Plant cells do not have centrioles (but still have spindles) |
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Term
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Definition
• An example of a genetic cross (breeding experiment) conducted by Mendel
• Tall Pea Plant crossed with a dwarf Pea Plant
(Tall Pea Plant - pure breeding)
ALL offspring were tall
What happened to the dwarf characteristics?
• Cross the tall offspring with each other:
• 3/4 tall offspring
• 1/4 dwarf offspring
• Mendel's 3:1 |
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Term
| Dominant, Recessive, Phenotype, Genotype, Heterozygous |
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Definition
• Dominant: phenotype requiring inheritance of just one copy of the relevant allele
• Recessive: phenotype that can only result from inheritance of two copies of the same allele (one from each parent)
• Phenotype: the physical expression of the genotype
• Genotype: the genetic makeup of the cell/organism
• Heterozygous: two different alleles, eg: Aa |
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Term
| Homozygous, Locus, Pure Breeding, F1 |
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Definition
• Homozygous: two of the same allele, eg: AA or aa
• Locus: the location of a gene on a chromosome
• Pure breeding: homozygous dominant
• F1: first filial generation |
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Term
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Definition
1. All individuals with the dominant phenotype are heterozygous
2. When heterozygous individuals are crossed, a 2:1 ration is obtained
3. When dominant individuals are crossed with recessive individuals, a 1:1 ratio is always obtained |
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Term
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Definition
| A condition in which both alleles of a gene pair in a heterozygote are fully expressed, with neither one being dominant or recessive to the other. |
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Term
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Definition
• A form of intermediate inheritance in which heterozygous alleles are both expressed, resulting in a combined phenotype
• For example, in cross-pollination experiments between red and white snapdragon plants the resulting offspring are pink |
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Term
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Definition
| when one allele determines a phenotype that is more dominant than the other but not completely dominant |
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Term
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Definition
• When there are more than two different alleles available within the population for a particular gene
• For example; the ABO blood grouping gene.
• There are three alleles |
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Term
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Definition
• When genes are situated on one of the sex chromosomes, they are said to be sex-linked
• (When genes are found on one of the autosomes, they are said to be autosomal)
• Refers to the X chromosomes unless otherwise states |
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Term
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Definition
• When genes are found on the same chromosome, they are said to be linked
• When genes are linked the rules of independent assortment do not apply |
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