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
Genetics, BIO 303
Midterm #1. Bio 303 - Genetics. Cal Poly San Luis Obispo.
| Question | Answer |
|---|---|
| When in interprhase is DNA replicated? | S Phase |
| Def: Centromere | A condensed or constricted region which establishes the general appearance of each chromosome. |
| What two periods of Interphase does DNA not replicate? | G1 and G2 |
| What is the haploid number of humans? | 23 |
| What is the diploid number of humans? | 46 |
| What is meant by reductive division in Meiosis? | -Takes cells from being 2n to 1n. -Takes either mom or dad genes. -Reduces amount of information of info in gametes by half -Gametes are "n" each |
| What is the difference between metaphase in mitosis and meiosis? | Mitosis: Individual chromosomes align at the metaphase plate Meiosis: Homologous pairs align at the metaphase plate |
| Stages of Meiosis | Interphse Prophase I Metaphase I Anaphase I Telophase I Prophase II Metaphase II Anaphase II Telophase II |
| Meiosis: Prophase I, Metaphase I, Anaphase I, Telophase I | Prophase: Chromosomes condense, synapsis of homologous chromosomes, crossing over. Metaphse: Tetrads migrate to metaphase plate. Anaphase: Homologs separate and begin moving to opp sides Telophase: Chromosomes move to opp sides, then cell separates |
| What is a tetrad? | Consists of two homologous chromosomes, with each homolog consisting of two sister chromatids. |
| What occurs in interphase? | Interphase: Chromosomes replicate in parent cells, in uncondensed state |
| Mitosis: Prophase, Metaphase, Anaphase, Telophase | Prophase: Chromosomes condense. Metaphase: Chromosomes are at middle of cell Anaphase: Sister chromatids separate. Pulled to opposites sides. Telophase: The nuclear envelope re-forms |
| What is ploidy? | The number of each type of chromosome present; equivalent to the number of haploid chromosomes sets present. |
| What are the end products of meiosis and mitosis? | Mitosis: 2 identical daughter cells Meiosis: produces 4 gametes |
| Def: Centriole, kinetochore | Centriole: One of the two cylindrical bodies that are found as part of the centrosome. Kinetochore: The protein structure on chromosomes where the spindle fibers attach during division to pull the chromosomes apart. |
| What is a "test cross"? | an organism expressing the dominant phenotype is crossed to a homozygous recessive individual; this allows determination of the genotype of the dominant organism. |
| What is the principle of segregation? | in the formation of gametes, the two copies of the gene separate (segregate) in such a way that each gamete is equally likely to contain either copy of the gene. |
| Principle of Independent Assortment | during gamete formation, segregation of any pair of genes is independent of the segregation of other pairs. (Also, some affect of recombination/crossing over.) |
| Probability - Sum Law | probability of a specific subset of possible events occurring is equal to the sum of the probabilities of each event when considered independently |
| Probability - Product Law | probability of 2 or more events occurring simultaneously is equal to the product of their individual probabilities |
| How do you know when to multiple probabilities or sum them? | And - multiply Or - sum |
| What is complete dominance? | Heterozygote looks like homozygote. |
| What is incomplete dominance? | Where both phenotypes are expressed |
| Haplodiploid | females diploid and males haploid |
| Sex-influenced inheritance is.... | where sex influences expression of phenotype. The trait shows up in both, but with different phenotypic expression |
| Penetrance | Measure of the percentage of individuals of a given genotype that manifest the expected phenotype. |
| Epistasis is? | A specific form of gene interaction in which alleles of one gene mask the phenotypic effect |
| Homogametic sex DEF | all gametes have some chromosome complement (XX or ZZ) |
| Heterogametic sex | Gametes can have different chromosome complements (XY or ZW) |
| When do the X and Y segregate themselves in Meiosis? | Anaphase I |
| Are the X and Y homologs? | NO |
| What is a pseudoautosomal region? | A region present in the human Y chromosome that is also represented on the X chromosome. Genes in this region of the Y chromosome have a pattern of inheritance that is indistinguishable from genes on autosomes. |
| What is genomic imprinting | Identical mutations (deletions) yield different phenotypes depending on which parent donated |
| Imprinting... | Turning a gene on or off |
| Extranucleur inheritnace | phenotype is caused at least in part by genes in mitochondrian or chloroplasts |
| In meiosis, when do the X and Y chromosomes pair? | Prophase |
| Dosage compensation | A genetic mechanism that equalizes the levels of expressive genes at loci on the X chromosome. |
| What is the result of dosage compensation? | a random inactivation of one X chromosome, leading to Barr Body formation |
| What are the two possibilities for dosage compensation? | 1) Turn off one X in females 2) Turn UP the X in males |
| Number of Barr Bodies = | Number of X chromosomes - 1 |
| All mammalian females (except XO) are mosaics for _____ _______ alleles | heterozygous X-linked |
| Nondisjunction | Failure of chromosomes to separate at anaphase |
| Aueuploidy | change in the number of individual chromosomes |
| Polyploidy | More than two complete sets of chromosomes |
| Autosomal monosomy is not lethal. True or false? | FALSE. It IS lethal |
| Are homozygous deletions always lethal? | YES |
| Are heterozygous deletions always lethal? | Not always |
| Translocation | Chromosomal segments are swapped |
| The effect of indipendant assortment is countered by _____ which is countered by _____. | Linkage Recombination |
| The farther two genes are on a chromosome, there is more or less likelhood that recombination will take place? | More |
| Completely linked genes behave as ____ ____. | One unit |
| Genes on the same chromosome show what kind of linkage? | Complete (due to crossing over) |
| Crossing over, with weak enough linkage, may actually look like _____ ______. | Independent assortment |
| Crossing over results in ______. | Recombination |
| ONe crossover between a pair of chromosomes leads to two _____ ____. | Recombinant chromatids |
| Recombinant frequency is the ____ of recombinant gametes. | SUM |
| Highest percentage of recombinant gametes you can get is | 50% |
| The closer that two genes are together, the more _____ they are linked. | Tightly |
| Closer together = more or less crossing over | LESS |
| What can reduce the amount of crossing over? | The presence of a centromere |
| What does percent recombination measure? | The proportion of meiosis in which crossing over happened between two genes. It also measures the distance between 2 genes on a chromosome |
| By determining the frequency of recombination, we can do what? | Map the genome. Map where a gene is on the chromosomes. |
| Polyploidy is | more than two complete sets of chromosomes |
| Nondisjunction is? | Failure of chromosomes to separate at anaphase. |
| What is allopolyploidy? What is the source? What are the effects? | Chromosome sets derived from two different species Source: hybridization between related species Effects: F! hybrids allodiploid and sterile. Allotetraploids can be fertile. |
Created by:
ahypnaro
Popular Biology sets