Term
| a eukaryotic cell where chromosomes exist in pairs. all human somatic cells are this |
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Definition
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Term
| a cell with only one set of chromosomes |
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Definition
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Term
| what is the diploid chromosome number in humans? |
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Definition
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Term
| which cells does mitosis occur in? |
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Definition
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Term
| which line does meiosis occur in? |
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Definition
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Term
| two individual chromosomes that were inherited from different parents are known as? |
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Definition
homologous pairs
aka homolouges |
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Term
ture/false
homologues are alike and have identical versions of genes at their corresponding loci? |
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Definition
false
they are alike but have different versions of genes at some of the corresponding loci |
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Term
| homologous chromosomes replicate to form sister... |
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Definition
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Term
| i am one of the two identical strands of a new replicated chromosome. what am i? |
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Definition
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Term
| meiosis produces how many gametes and how many chromosomes do they contain? |
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Definition
| meiosis produces 4 gametes and they contain n (diploid) chromosomes |
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Term
| what is the mechanism by which diploid cells produce haploid cells during gamete formation? |
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Definition
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Term
| how many cell divisions does meiosis involve? |
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Definition
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Term
| which meiosis am i? my chromosomes replicate and recombination occurs. homologous chromosomes seperate and produce 2 haploid cells? |
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Definition
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Term
which meiosis is this?
the chromatids seperate producing four haploid gametes? |
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Definition
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Term
meiosis 1 which stage?
chromosome replicate to form pairs of chromatids but chromosomes have not yet condensed |
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Definition
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Term
| in which stage of meiosis one does synapsis occur? |
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Definition
prophase one
here is where the tetrad forms and crossing over takes place at chiasmata |
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Term
| where does synapsis, crossing over at chiasmata and formation of a tetrad occur? |
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Definition
| prophase 1 of meiosis one |
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Term
| what is synapsis and where does it occur? |
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Definition
| synapsis is unique to mieosis. it is the pairing of homologous chromosomes and occurs in prophase 1 in meiosis 1 |
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Term
true of false?
when chromosomes line up on the metaphase plate in metaphase 1 they are still in tetrads? |
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Definition
this is true.
the orientation of each tetrad is random |
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Term
what seperates in Anaphase 1?
sister chromatids or homologous chromosomes? |
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Definition
| homologous chromosomes seprate and move towards oppostie poles but sister chromatids remain attached |
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Term
| in telophase and cytokinesis 1 is DNA replicated? |
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Definition
No DNA is not replicated
two haploid cells form - chromosomes still double pairs of chromatids but they either have maternal or paternal dna |
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Term
| two BB would be known as? |
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Definition
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Term
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Definition
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Term
| in which phase does the nuclei form at opposite poles, cytokenesis occurs and results in four haploid daughter cells (gametes)? |
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Definition
| Meiosis II final phase: Telophase and Cytokinesis |
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Term
| where do meiosis and mitosis occur? |
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Definition
mitosis in somatic body cells
meiosis in the germ line |
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Term
| compare cell divisions in mitosis and meiosis |
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Definition
mitosis - 1 cell division
meiosis - 2 cell divisions |
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Term
| compare the products of mitosis and meiosis |
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Definition
mitosis - 2 identical diploid cells
meiosis - 4 non identical haploid cells |
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Term
| I am also known as reductional division |
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Definition
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Term
| I am also known as equational division |
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Definition
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Term
| In somatic cells, chromosomes occur in... |
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Definition
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Term
| chromosome pairs segregate ...............into gametes |
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Definition
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Term
| different chromosome pairs assort..... |
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Definition
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Term
| where does the chromsome theory og inheritence state the 'inheritable factors' are located? |
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Definition
| specific positions (loci) on chromosomes |
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Term
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Definition
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Term
| where in particular are genes located on a chromosome? |
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Definition
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Term
true or false?
genes can exist in different forms of alles? |
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Definition
| true.. one on each member of a pair of homologous chromosomes |
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Term
| how many alleles do we inherit from each parent? |
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Definition
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Term
| how does chromosome behaviour in meiosis explain Mendels Law of Segregation? |
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Definition
mendels law : 2 forms of alleles present in each parent seperate independantly
meiosis: homologous pairs of chromosomes move to opposite poles in anaphase I |
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Term
| How does chromosome behaviour in meiosis explain Mendel's Law of Independant Assortment? |
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Definition
mendels law: each pair of alleles assorts independantly of each other pair of alleles during gamete formation
meiosis : explained by the random way homologous pairs line up on the metaphase plate during meiosis I |
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Term
learn this Law
Law of segregation - the 2 alleles present in each diploid parent seperate independantly (ie. only one is passed to each progeny) |
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Definition
| This is demonstrated in meiosis I as homologous pairs seperate and move to opposite ends of the poles. |
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Term
Learn this Law too:
Different pairs of alleles assort independantly to produce different combinations in the progeny |
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Definition
| This is demonstrated with the random arrangement of the chromosomes at the metaphase plate in meiosis I |
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Term
what am i defining?
i am the process of genetic recombination that gives rise to new combinations of linked genes |
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Definition
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Term
| which phase does crossing over take place in? |
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Definition
| the pachytene phase of Prophase I |
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Term
| how does the crossing over process begin and what else is involed? |
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Definition
the process begins with synapsis - the pairing of homologous chromosomes
the synaptonemal complex holds the homologous chromosomes together like a zipper in a tetrad. |
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Term
| the formation of what leads to crossing over between homologous chromsomes? |
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Definition
synaptonemal complex
the cross over part is called the chiasma and the crossed over alleles are called the recombinant chromatids |
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Term
| what is the result of crossing over? |
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Definition
| recombinant chromosomes with new combinations of linked genes |
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Term
| name the four sources of genetic variability in sexual life cycles |
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Definition
| mutation, independant assortment, crossing over, random fertilisation of ova by sperm |
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Term
what does this figure signify?
223 8,388,608 |
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Definition
the number of possible combinations of paternal/maternal chromosome types
combinations in offspring is 246 and crossing over adds even more variation |
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