Term
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Definition
| Unit of heredity. (Sequence of Nucleotides that codes for a single polypeptide.) |
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Term
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Definition
| A gene's specific physical location on a specific chromosome. |
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Term
| How do mutations lead to genetic variability? |
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Definition
| Small changes in DNA lead to the production of different proteins. |
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Term
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Definition
Different versions of a gene.
Example: Tongue Rolling v. Flat Tongues |
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Term
| What is the difference between a diploid and a haploid chromosome? |
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Definition
A diploid chromosome is 2 chromosome sets joined together by a centromere (2n). DNA replication has occured.
A haploid chromosome is only one chromosome set (1n).
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Term
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Definition
Pair of chromosomes which carry all the same genes in the same loci. (These genes are found NOWHERE else).
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Term
| What are the 2 functions of Meiosis? |
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Definition
1. Turn diploid chromosomes into haploid chromosomes.
2. Promote genetic diversity. |
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Term
| What happens during Prophase I? |
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Definition
Chromosomes condense. Homologous pairs come together locus to locus (synapsis). Crossing over may occur.
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Term
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Definition
Reciprocal exchange between homologous pairs.
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Term
| What happens during Metaphase I? |
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Definition
Homologous pairs line up along the metaphase plate (along the equator).
[image] |
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Term
| What happens during Anaphase I? |
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Definition
Homologous pairs separate and the chromosomes migrate toward the poles.
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Term
| What happens during Telophase I and Cytokinesis? |
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Definition
The cell is transformed from a diploid cell into a haploid cell as the homologous pairs are separated into 2 separate cells.
[image] |
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Term
| What is Independent Assortment and when does it occur? |
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Definition
Independent Assortment happens during Metaphase I. During this phase, the chromosomes can line up in any order... it's simply luck.
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Term
| What is the formula for calculating the number of different combinations which can occur through independent assortment alone? |
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Definition
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Term
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Definition
Meiosis II is just like mitosis, but 2 haploid cells divide into 4 haploid cells. Because of crossing over and indepentent assortment, the cells are not identical.
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Term
| Explain nondisjuction and when it occurs. |
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Definition
Nondisjuction is when chromosomes fail to separate. This can occur during Anaphase I between homologous pairs or Anaphase II between sister chromatids.
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Term
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Definition
Condition in which the Zygote has an abnormal number of chromosomes due to nondisjunction (2n+1 or 2n-1).
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Term
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Definition
Another reproduction method aside from sexual reproduction. In this case, an unfertilized egg produces an individual through mitosis; however, no evolution can occur because there is no oppurtunity for crossing over and independent assortment.
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Term
| Explain Mendel's Law of Segregation |
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Definition
Each gene pair segrgates during gamete formation, so each gamete receives only one copy of the gene.
AKA Meiosis |
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Term
| Describe the 3 Different Genotypes |
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Definition
Homozygous Dominant: 2 Copies of the dominant allele present (RR).
Homozygous Recessive: 2 copies of the recessive allele present (rr).
Heterozygous: One copy of the dominant and recessive allele present (Rr). |
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Term
| What is the typical phenotypic ratio for a monohybrid cross? |
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Definition
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Term
| What is the typical phenotypic ratio for a dihybrid cross? |
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Definition
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Term
| Describe Mendel's Law of Independent Assortment. |
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Definition
| Which allele of a gene pair goes into a particular gamete is indendent of where the alleles of another gene pair go. This happens during Metaphase I. |
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Term
| Define incomplete dominance. |
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Definition
In the heterozygote, neither allele can be fully expressed.
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Term
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Definition
In the heterozygote, both alleles are fully expressed.
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Term
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Definition
One gene influences the expression of another gene at a different locus.
[image] |
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Term
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Definition
Genes on the same chromosome that tend to be inherited together.
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Term
| What is the typical phenotypic ratio for linked genes? |
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Definition
| 3:1 because there is only one homologous pair. |
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Term
| What are some of the mechanisms of gene expression? |
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Definition
| Promoters, Repressors, Activators, Alternative Splicing. |
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Term
| What are the 2 types of chromosomes animals have? |
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Definition
| Autosomal and sex chromosomes. |
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Term
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Definition
| Sex-determining Region on the Y chromosome, tells the body to make gonads instead of ovaries. |
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Term
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Definition
Genes which are found exclusively on either the X or the Y chromosome.
Males are hemizygous.
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Term
| What did T.H. Morgan's work with fruit flies (Drosophilia melanogaster) support? |
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Definition
| That crossing over was occuring. |
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Term
| What is the equation for the Recombination Frequency? |
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Definition
Number of Recombinants
Total of Offspring
391/2300=0.17=17% Chance of crossing over taking place, and that the genes are 17 map units apart. |
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Term
| Are farther apart or closer together gene more likely to cross over? |
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Definition
Farther apart genes are more
likely to cross over because there's more spots for breakage between them.
In fact, if the genes are really far apart they begin to ac
t
a
s i
f the
y are on different chromosomes. |
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Term
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Definition
A Localized Group of Individuals of the same species that can interact and interbreed sucessfully.
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Term
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Definition
The genetic make-up of a population. Sum total of all the alleles in the population.
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Term
| What allows a population to be in equilibrium? |
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Definition
| If the frequency of alleles does not change from one generation to the next. |
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Term
F1 Generation: AA 320 Aa 160 aa 20
Determine if this population is in equilibrium. |
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Definition
Genotype#|Gen.Freq|Loci #A|Loci #a
AA 320 | 320/500=.64 | 640 | 0
Aa 160 | 160/500=.32 | 160 | 160
aa 20 | 20/500=.04 | 0 | 40
500 | 500/500=1.00 | 800+200=1000
Freq of A allele: 800/1000= .8
Freq of a allele 200/1000= .2
F2 : AA .64 Aa .32 aa .04
Same as F1 |
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