Term
| How many genes do humans have? |
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Definition
|
|
Term
| What is the relationship between gene number and genome size? |
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Definition
|
|
Term
| All eukaryotes have at least _____ chromosomes? |
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Definition
|
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Term
| Where does DNA replication occur in eukaryotes? |
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Definition
| At one of the multiple origins of replication |
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Term
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Definition
| The chromosomes of a genome |
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Term
| How many chromosomes do humans have? |
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Definition
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Term
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Definition
|
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Term
| What are sister chromatids? |
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Definition
| Both copies of the chromosome held together at the centromere |
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Term
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Definition
| The point at which two sister chromatids are held together |
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Term
| What are the four types of centromere position? |
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Definition
| Meta, submeta, acro and telo |
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Term
| Where is the centromere on a metacentric chromosome? |
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Definition
|
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Term
| Where is the centromere on a submetacetric chromosome |
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Definition
| Just above or below the middle |
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Term
| Where is the centromere on an acrocentric chromosome? |
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Definition
|
|
Term
| Where is the centromere on a telocentric chromosome? |
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Definition
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Term
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Definition
| The ends of each chromosome that have repeat A's, G's and T's |
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Term
| Which is the shorter arm of a chromatid? |
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Definition
|
|
Term
| Which is the longer arm of the chromatid? |
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Definition
|
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Term
| What are the two functions of telomeres? |
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Definition
| Solve the end replication problem and allow the cell to distinguish the end of a chromosome |
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|
Term
| What is the end replication problem? |
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Definition
| DNA polymerase does not know where the end of the chromosome is so it replicates some of the telomere until it realises it has finished repliaction |
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Term
| What happens as a result of the end replication problem? |
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Definition
| The telomeres get shorter and shorter |
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Term
| Which enzyme prevents chromosome shortening? |
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Definition
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Term
| Why is telomerase usually turned off in somatic cells? |
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Definition
| To cause the cells to die after a while so cancer can not develop |
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|
Term
| Which organisms lives longer due to the presence of telomerase? |
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Definition
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Term
|
Definition
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Term
|
Definition
| Proteins that DNA is wrapped around to keep it condensed in the nucleus |
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Term
| How many times is DNA wrapped around one histone? |
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Definition
|
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Term
| What are the four types of unusual chromosome? |
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Definition
| Minichromosomes, Beta, Holocentric and Polytene |
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Term
|
Definition
| Short, gene dense chromosomes |
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Term
| Which organism has minichromosomes? |
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Definition
|
|
Term
| What are Beta chromosomes? |
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Definition
|
|
Term
| What are holocentric chromosomes? |
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Definition
| Chromosomes with multiple kinetochores |
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|
Term
| What are polytene chromosomes? |
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Definition
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Term
| Where are polytene chromosomes found in the Drosophila? |
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Definition
|
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Term
| How are polytene chromosomes formed? |
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Definition
| Repeated replication of homologous chromosomes without division |
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Term
|
Definition
| The banding pattern on polytene chromsomes |
|
|
Term
| What is the chromocentre? |
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Definition
| The piece of DNA that holds the polytene chromosome together |
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|
Term
| What have polytene chromosomes been used for? |
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Definition
| Providing detail for mapping chromosomes |
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Term
|
Definition
| The division of cells to produce 2 genetically identical daughter cells |
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Term
| What four things is mitosis required for? |
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Definition
| Embryonic development, replacement of skin, wound healing and the production of reticulocytes |
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Term
| Uncontrolled mitosis leads to what? |
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Definition
|
|
Term
| What are the five stages of mitosis? |
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Definition
| Prophase, Prometaphase, metaphase, anaphase and telophase |
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Term
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Definition
| The protein structure at the center of centromeres that allow spindle fibres to attach |
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Term
|
Definition
| Microtubules that create an axis for mitosis |
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|
Term
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Definition
| A cytoplasmic organelle with nine groups that divide to form the mitotic spindle |
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Term
|
Definition
| The region of the cytoplasm that contain the two centrioles |
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|
Term
| During mitosis, what happens during the interphase of G2? |
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Definition
|
|
Term
| During mitosis, what happens during prophase? |
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Definition
| Chromosomes condense and centrioles divide and move apart |
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|
Term
| During mitosis, what happens during prometaphase? |
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Definition
| Chromosomes form chromatids, centrioles reach opposite poles and spindle fibres attach to the kinetchore |
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|
Term
| During mitosis, what happens during metaphase? |
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Definition
| Centromeres aline along the metaphase plate |
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|
Term
| During mitosis, what happens during anaphase? |
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Definition
| Centromeres divide and each daughter chromosome is pulled to each pole |
|
|
Term
| During mitosis, what happens during telophase? |
|
Definition
| Nuclear envelope reforms and chromosome reforms |
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|
Term
| During mitosis, what happens during cytokinesis? |
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Definition
|
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Term
|
Definition
| The production of four haploid gamete cells from one diploid somatic cell |
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|
Term
| What are the two phases of meiosis? |
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Definition
|
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Term
| What are the names of the five stages in the prophase of meiosis one? |
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Definition
| Leptonema, zygonema, pachynema, diplonema and diakinesis |
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Term
| In meiosis one, what happens during the leptotene phase of prophase? |
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Definition
| Duplicated chromosomes condense |
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Term
| In meiosis one, what happens during the zygotene phase of prophase? |
|
Definition
| Bivalents form and synapsis begins |
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|
Term
| In meiosis one, what happens during the pachytene phase of prophase? |
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Definition
|
|
Term
| In meiosis one, what happens during the diplotene phase of prophase? |
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Definition
| Formation of a visible chiasmata and disapearence of synaptonemal complexes |
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|
Term
| In meiosis one, what happens during the diakinesis phase of prophase? |
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Definition
| Nuclear membrane fragments |
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|
Term
| How often does crossing over occur? |
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Definition
| At least once on each chromosome |
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|
Term
| Which organism does not do crossing over? |
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Definition
|
|
Term
| What is the synaptonemal complex? |
|
Definition
| A zipper that forms between the two chromosomes to aid crossing over |
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|
Term
| In meiosis one, what happens during metaphase? |
|
Definition
| Alignment of tetrads on metaphase plate |
|
|
Term
| In meiosis one, what happens during anaphase? |
|
Definition
|
|
Term
| In meiosis one, what happens during telophase? |
|
Definition
| Nuclear membrane forms around dyads and cell division |
|
|
Term
| How does meiosis one differ from meiosis two? |
|
Definition
| No DNA replication and no crossing over |
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|
Term
| What happens between meioisis one and meiosis two? |
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Definition
| Short interphase or straight into meioisis two |
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|
Term
| In meiosis two, what happens during prophase? |
|
Definition
| Nuclear membrane breaks down |
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|
Term
| In meiosis two, what happens during prometaphase? |
|
Definition
|
|
Term
| In meiosis two, what happens during metaphase? |
|
Definition
| Alignment of dyads on metaphase plate |
|
|
Term
| In meiosis two, what happens during anaphase? |
|
Definition
| Division of centromeres and migration of each monad to each pole |
|
|
Term
| In meiosis two, what happens during telophase? |
|
Definition
| Formation of nuclear membrane |
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|
Term
| In meiosis two, what happens during cytokinesis? |
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Definition
|
|
Term
| How do spermatogenesis and oogenesis differ? |
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Definition
| Spermatogenesis produces four haploid cells continuously but in oogenesis only one egg is produced and all eggs are stopped at prophase one in the fetus |
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|
Term
| What happens when disjunction occurs during meioisis? |
|
Definition
|
|
Term
|
Definition
| Chromosome number is not an exact multiple of the haploid number |
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|
Term
|
Definition
| Three copies of a chromosome rather than two |
|
|
Term
| A trisomy at chromsome 8 causes what? |
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Definition
|
|
Term
| A trisomy at chromsome 12 causes what? |
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Definition
|
|
Term
| A trisomy at chromsome 18 causes what? |
|
Definition
|
|
Term
| A trisomy at chromsome 13 causes what? |
|
Definition
|
|
Term
| A trisomy at chromsome 21 causes what? |
|
Definition
|
|
Term
| What are the five differences between meiosis and mitosis? |
|
Definition
1)Meiosis is a reductional division
2)Meiosis produces genetic variation
3)Meiosis has two nuclear divisions
4)Meiosis can only occur in diploid cells
5)Meiosis can only occur in gamete producing cells |
|
|
Term
| Why can assexual reproduction happen twice as fast? |
|
Definition
| All of the individuals can produce offspring |
|
|
Term
| What is the advantage of sex? |
|
Definition
| Produces variation which allows the population to survive better when environmental changes occur |
|
|
Term
| Which strain of yeast has a faster growth in harsher conditions, sexual or assexual? |
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Definition
|
|
Term
| What is the Protenor Mode of Sex Determination? |
|
Definition
| Males have 13 chromosomes with one X chromosome and females have 14 chromosomes with two X chromosomes and so sperms produce either 7 chromosomes or six |
|
|
Term
| What is the Lygaeus Mode of Sex Determination? |
|
Definition
| Females have 12 autosomes with two X and males have 12 autosomes with one X chromosome and one Y chromosomes and the sperm produce 6 autosomes with either an X or a Y |
|
|
Term
| What is the heterogametic sex? |
|
Definition
| The sex that produces one of each sex chromosome |
|
|
Term
| What is the homogametic sex? |
|
Definition
| The sex that produces two of the same sex chromsome |
|
|
Term
| How do we distinguish between homgametic and heterogametic males? |
|
Definition
|
|
Term
| How do we distinguish between homgametic and heterogametic females? |
|
Definition
|
|
Term
| What is caused by the genotype XXY? |
|
Definition
|
|
Term
| What genotype causes Klinefelters syndrome? |
|
Definition
|
|
Term
| What is caused by the genotype XO? |
|
Definition
|
|
Term
| What is the genotype that causes Turners Syndrome? |
|
Definition
|
|
Term
| What did Turners and Klinefelters syndrome prove? |
|
Definition
| That the Y chromosome determined maleness |
|
|
Term
| Where did the Y chromosome originate? |
|
Definition
| As a full size chromosomal pair with the X chromosome |
|
|
Term
| What does the Y chromosome code for? |
|
Definition
| 26 male fertility proteins |
|
|
Term
| What does PARs stand for? |
|
Definition
|
|
Term
| What do the PARs on the Y chromosome do? |
|
Definition
| Synapse with the X chromsome |
|
|
Term
|
Definition
|
|
Term
| What does the MSY on the Y chromosome do? |
|
Definition
| It doesn't synapse with the X chromsome |
|
|
Term
| What does the SRY on the Y chromosome do? |
|
Definition
| Produces TDF that creates the testis in the embryo |
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|
Term
|
Definition
|
|
Term
|
Definition
| Testis determining factor |
|
|
Term
| What environmental factor can affect sex determination in some reptiles? |
|
Definition
|
|
Term
| How can temperature affect sex determination? |
|
Definition
| It controls enzymes and inhibitors involved in making males and females |
|
|
Term
| What is dosage compensation? |
|
Definition
| The removal of one X chromosome in females |
|
|
Term
| What are inactivates X chromosomes called? |
|
Definition
|
|
Term
| Why does dosage compensation occur? |
|
Definition
| So that the female does not get twice the dose of her X chromsome |
|
|
Term
| What are the two examples of X-Mosacism in humans? |
|
Definition
| Anhidrotic Ectodermal Dysplasia and Red/Green Colour blindness |
|
|
Term
| What is Anhidrotic Ectodermal Dysplasia? |
|
Definition
| X-linked mutation that causes the absence of sweat glands |
|
|
Term
|
Definition
| The belief that inactivation of the X-Chromosome is random at an early point in development and then all cells have the same number of activated X-chromosomes |
|
|
Term
| What specifically deactivates the X-Chromosome? |
|
Definition
| The X-inactivation centre |
|
|
Term
| What two non-coding RNA transcripts are produced from the XIC? |
|
Definition
|
|
Term
|
Definition
| Coats one X Chromosome to cause it condense into heterochromatin |
|
|
Term
|
Definition
| Densely compacted inactivated X-chromosome |
|
|
Term
| What percentage of genes of the inactivated X-chromosome escape inactivation? |
|
Definition
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