Term
| What is interphase? What parts of the cel cycle are included in interphase? Know the 4 stages of the cell cycle.... |
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Definition
-Interphase refers to all stages of the cell cycle other than mitosis. During interphase, cellular organelles double in number, the DNA replicates, and protein synthesis occurs. The chromosomes are not visible and the DNA appears as uncoiled chromatin.
G1 stage - first stage in interphase, during which cellular growth and development takes place; precedes DNA synthesis or the S stage .
S-phase - second stage of interphase between G1 and G2; period of DNA replication.
G2 stage - third stage of interphase during which organelle replication and protein synthesis takes place; follows DNA synthesis or the S stage.
--Stages of the cell cycle: Prophase, Metaphase, Anaphase, Telophase |
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Term
| Also know the stages of mitosis and the main events of each |
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Definition
prophase - stage of mitosis in which replicated chromosomes condense; nuclear membrane dissociates; centrioles migrate to the poles of the cell.
metaphase - stage of mitosis in which replicated chromosomes align at the center of the cell.
anaphase - phase of mitosis where sister chromatids separate and daughter chromosomes migrate to opposite poles of the cell.
telophase - mitotic stage where nuclear membrane reforms and the spindle fibers disappear. |
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Term
| During which phase of the cell cycle are chromosomes duplicated? |
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Definition
| During the “s” phase in interphase. |
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Term
| 5. What are chromatids? How many chromatids does a chromosome have before S phase? How many does it have after S phase? |
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Definition
Chromatids- two daughter strands of a replicated chromosome that are joined by a single centromere. They separate during cell division to become individual chromosomes.
In Humans:
Before- 23
After- 46 |
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Term
| 6. Which does crossing over happen in, mitosis or meiosis? |
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Definition
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Term
| What is the spindle? Is it a permanent structure in the cell? What are the little cables called that form the spindle? |
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Definition
| A spindle is an aggregate of microtubules that move chromosomes during cell division. Spindles are not permanent structures in the cell, but they are necessary for cell division. The little cables that form spindle fibers are called microtubules. |
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Term
| . In which phase of mitosis do the chromosomes condense? In which phase are they all lined up on the spindle? In which phase do sister chromatids separate? |
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Definition
| In mitosis chromosomes condense in prophase the first phase in mitosis. Metaphase is when the chromosomes are all lined up on the spindle. The sister chromatids separate during Anaphase. |
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Term
| What do we call sister chromatids as soon as they have separated? |
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Definition
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Term
| What are the names of all 4 stages of mitosis and in what order do they occur? |
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Definition
1.Prophase
2. Metaphase
3. Anaphase
4.Telophase |
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Term
| When skin cells in your arm divide, are they doing mitosis or meiosis? |
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Definition
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Term
| Homologous chromosomes separate in: (choose one: mitosis, or meiosis). |
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Definition
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Term
| Are humans diploid or haploid? What does it mean to be diploid? |
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Definition
| Humans are diploid meaning that they carry the full compliment of chromosome in each cell (2n) one from their mother and one from their father. Homologous copies of each chromosome. |
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Term
| What do we call different forms or versions of the same gene |
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Definition
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Term
| What are gametes? (in other words, which type of cells in our bodies are gametes?) |
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Definition
| Cells that fuse with other cells to form a new organism. In males: sperm, and in females: ovum |
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Term
| 16.- Are gametes diploid or haploid? |
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Definition
| Gametes are haploid and when they fuse they become a diploid organism. |
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Term
| Meiosis results in: (choose one |
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Definition
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Term
| .- There is a separation event in meiosis 1 and again, another separation event in meiosis 2. What separates in meiosis 1, and what separates in meiosis 2? |
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Definition
| In anaphase of meiosis 1 the chromosomes separate but do not split at their centromeres and in anaphase of meiosis 2 the sister chromatids split at their centromeres and separate. Both divisions result in haploid cells being formed |
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Term
| Which division (choose either meiosis 1 or meiosis 2) most closely resembles mitosis |
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Definition
| Meiosis 2 because sister chromatids actually separate at their centromeres, and they both end with cytokinesis while meiosis one ends with interkinesis and a short rest period not involving replication. |
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Term
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Definition
| A locus is the position of a gene on a genetic map, the specific place on a chromosome where the gene is located. In a broad definition it is any chromosomal location that exhibits variation detectable by genetic or molecular analysis. |
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Term
| 2. What is a genotype? What is a phenotype? If I said that my tomato plant produced juicy tomatos, is that a genotype or phenotype? If I said that it had the dominant juicy gene, JJ, is that a genotype or phenotype? |
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Definition
The genotype is the complete genetic makeup of an organism. The term is commonly used in reference to the specific alleles present at just one or a limited number of genetic loci.
The phenotype is the observable characteristics of an organism that are produced by the genotype and its interaction with the environment.
Juicy in this sense would be the phenotype
JJ would be the genotype but the fact that it is juicy is still the phenotype. |
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Term
| 3. Which is completely homozygous: (choose one) a) AaBB b) AaBB c) aaBB d) aaBb e) AaBb |
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Definition
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Term
| 4. If in a plant, B is dominant to b, and that plant is heterozygous at the B locus, does this plant have the dominant or the recessive phenotype? (Hint, first figure out its genotype. It is heterozygous. Then remember what it means to be dominant). |
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Definition
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Term
| 5. Who was the father of genetics? What organism did he do experiments on? (Hint, he was a monk) |
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Definition
| Gregor Johann Mendel was the father of genetics. He was an Augustinian monk. He experimented on garden peas. |
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Term
| 6. If in a cross, we count offspring, and there are lots and lots of them, and all of them, 100%, of the offspring are Aa, what are the parents |
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Definition
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Term
| 7. In a Punnett square, what do we write in all the little boxes inside the square? |
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Definition
Alleles
Remember that gametes have only 1 of each gene. Remember how to draw a P. square. Remember that gametes where you are following 2 linked genes will only come in two types, unless a crossover occurs. Then there are 4 types. |
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Term
| 8. How many different kinds of gametes with respect to the A gene, can an AA individual produce |
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Definition
One only A
How many kinds of gametes can an aa individual produce?
One only a
How many kinds of gametes can an Aa individual produce?
Two one A one a |
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Term
| 1. How many kinds of gametes can this individual produce? AaBbCC? |
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Definition
| Answer: Each gamete has to have one A, one B, and one C. Can have either version of each, but not both. 2 possibilities for A/a, 2 possibilities for B/b, and 1 possibility for C. = 2 X 2 X 1 = 4. Count them: ABC, AbC, aBC, abC. That is 4. |
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Term
| 4. What is a monohybrid cross |
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Definition
| A Monohybrid cross is a cross between parents who are heterozygous at one locus; for example, Bb x Bb (see the Punnett square below). |
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Term
| What is a dihybrid cross? |
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Definition
| A dihybrid cross is a cross between two individuals that differ in two traits. For example: RRyy/rrYY or RRYY/rryy. |
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Term
| 12. What is a test cross? What is it used for (what question are you asking, which the results of the test cross answer?) |
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Definition
| A cross of an individual of unknown genotype, usually expressing the dominant phenotype, with a homozygous recessive individual to determine the unknown genotype. For example you have a plant that is red and tall R-T-both dominant genes and you want to know if it is homozygous dominant or heterozygous dominant. You cross it with a short white plant rrtt if you get all red tall offspring then you know that the unknown was most likely RRTT but if you get some red tall some red short and some white short then you know that the unknown was RrTt |
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Term
| 13. For alleles of genes to assort independently, they must be on different ___ |
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Definition
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Term
| 15. If black fur color in bears is controlled by a dominant allele (B) and brown by its recessive allele (b), give the genotypes of the parents and offspring of a cross of black male and brown female that produce 1/2 black offspring and 1/2 brown offspring. (Hint: a black bear could possibly have one of 2 different genotypes, but the brown bear can only have one. So try both genotypes for the black bear, and cross them both to the brown bear, and see which gives 50% black and 50% brown.) |
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Definition
| The male bear has to be Bb (black) because when mated with a bb (brown) female it would produce 50% Bb (black) and 50% bb (brown) |
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Term
| 16. What is a karyotype? (hint, it involves photography) |
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Definition
| A complete set of all the metaphase chromosomes in a cell consisting of 2 chromatids per chromosome. Species specific arranged by size and position of the centromere. In humans the chromosomes are numbered for easy identification. |
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Term
| 17. Chromosomes that are NOT sex chromosomes are called ____. |
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Definition
| They are called autosomes |
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Term
| 18. Genetic recombination happens more often between two genes on the same chromosome, if those genes are ____. It happens less often if they are _____. |
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Definition
| If the genes are farther away on the chromosome they cross over at a higher rate then if they are closer together. |
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Term
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Definition
The ability of a single gene to have multiple phenotypic effects
Pleiotropy seems to be the main cause of genetic correlations such as how certain eye colors TEND to match certain hair colors or skin colors. This is the most likely reason for association among hair color, eye color, and skin color in humans. A single gene rarely affects only a single trait. |
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Term
| How is codominance different from incomplete dominance? |
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Definition
Codominance: The condition in which an individual heterozygous for a gene exhibits the phenotypes of both homozygotes
Ex. AB blood type. Neither A nor B antigen masks the other but are codominant and offspring produve both A antigen and the B antigen, not something in between, but both of the homozygous parental phenotypes.
Incomplete Dominance: The condition in which neither of two alleles is completely dominant to the other, so that the heterozygote has a phenotypes between the phenotypes of individuals homozygous for either allele involved.
Ex. Red flower (RR) x White flower (WW) = Pink flower (RW) |
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Term
| How is penetrance different from expressivity? |
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Definition
Penetrance: the frequency with which a dominant or homozygous recessive gene is phenotypically expressed within a population
Ex. How many of the offspring are “tall” (tall= 6.0 ft and taller)
Expressivity: the degree to which a particular gene is expressed in the phenotype. A gene with variable expressivity can cause a range of phenotypes.
Ex. What height are they exactly IN the tall region. To what degree of tallness? |
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Term
| What is a hypomorph? A null? |
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Definition
Hypomorph: a mutant with less than the normal amount of some gene product
Null: a null allele an allele whose affect is either an absence of normal gene product at the molecular level or an absence of normal function at the phenotypic level |
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Term
| What is a dominant negative? Hint: think of the 2 cars in the driveway example |
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Definition
A loss-of-function mutation normally results from a dominant negative mutation. It is a mutation whose gene product adversely affects the normal wildtype gene product within the same cell. The mutant product usually interacts with the same elements and results in a protein that is structurally similar to the wild type protein but has a loss of function or some aspect of the function.
This is the 2 cars in the driveway example. IF you have a long, narrow driveway and you park one car in front (representing the normal, dominant gene) and then park another broken down car behind it (representing the mutant, gene) it blocks the function of the working car because you can’t get it out without moving the broken-down car that won’t work. |
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Term
| What are all the reasons that in a cross, you don’t get the “expected” ratio of phenotypes, like 9:3:3:1? (I can think of at least 3 reasons) |
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Definition
Any deviation from the expected ratio is tell sign that two or more genes may be involved to produce that phenotype.
Linked* - If the genes are linked certain phenotypes (the parental strand) are more likely to occur and other phenotypes may not be represented.
Mortality* – Certain genotypic combinations will cause death or non-development in offspring. This group will not be represented in the offspring total or in the sub-groups.
Epistasis* – This may add more ( or less ) phenotypes than anticipated.
Mutations – (always causing problems) may give any of the above mentioned results. |
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Term
| How might you cross two individuals and use the new-fangled genetic markers to follow the offspring of the cross, instead of “traditional” phenotypes? |
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Definition
OK. First: “fangled”- adj. New made; hence, gaudy; showy; vainly decorated.
Genetic markers are often mutations that give a distinguishable phenotype. This makes for an easy and obvious count of the offspring from the cross. (I’m not sure what else to say…I called the prof. here is what we need:)
Go beyond physical and visually perceived phenotype and look to sequencing the genome of the offspring. STS’s (sequence tagged sites) and EST’s (expressed sequence tags) will be very helpful in this task. In order to use these you need to have some type of PCR primers to PCR up a sequence of a desired gene. From these you can make a genetic picture of the phenotype. This is especially useful when you are seeking a specific/desired phenotype.
Example application: corn plant height. PCR DNA of all the babies (!?) and see how the gene for height associates on the genome. By knowing half of the genetic picture you have a good idea of what the other half looks like because of what the parents’ look like. |
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