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
Ap Bio Mod 27-30
Ap Bio Module 27-30
| Question | Answer |
|---|---|
| P₁ | The original parents in a genetic cross; |
| F₁ | The offspring of the P1 cross; |
| monohybrid cross | A genetic cross that tracks one trait (one gene with two alleles), usually between heterozygous individuals -produces a 3:1 phenotype ratio in the F₂ generation. |
| Critical value | Threshold from chi-square table; if χ² (chi square) > critical value → reject null hypothesis. |
| Null hypothesis | Assumes no difference between observed and expected results. |
| Chi-square (χ²) | Tests if observed data fits expected ratios. |
| Incomplete dominance | when a Heterozygote genotype shows a phenotype that is the blend of the two alleles, - not full dominance. -Ex: Dominant flower color= Red , recessive= white flower color Heterozygous flower color= pink (mixture of the two) |
| Codominance | Both alleles are fully expressed in the heterozygote. Example: Blood type AB → both A and B antigens show. |
| Dihybrid cross | A genetic cross that tracks two traits (two genes), usually heterozygous for both. -Typical F₂ phenotype ratio: 9:3:3:1. |
| 9:3:3:1 ratio (from a dihybrid cross): | 9 → both dominant traits expressed (AABB) 3 → first dominant, second recessive (AAbb) 3 → first recessive, second dominant (aaBB) 1 → both recessive traits (aabb) -Occurs when Both parents are heterozygous for both traits Ex: (AaBb × AaBb). |
| Independent Assortment | Alleles for different genes separate independently during gamete formation. Explains why the 9:3:3:1 ratio appears—traits are inherited separately, not linked. |
| What does this mean in a pedigree? ⬛ | A male affected with a disease |
| What does this mean in a pedigree? ⬜ | A male that is not affected with a disease |
| What does this mean in a pedigree? ⚪ | A female not affected with the disease |
| What does this mean in a pedigree? ⚫ | A female affected with the disease |
| Pleiotropy | One gene affects multiple traits. Example: Sickle-cell allele affects blood shape, oxygen transport, and disease resistance. |
| Epistasis | One gene masks or modifies the expression of another gene. Ex:Mouse coat color: One gene determines fur color (black or brown). A second gene determines whether pigment is produced at all. |
| F₂ | The offspring produced by crossing F₁ individuals with each other. |
| Addition Rule (probability): | P(A or B)=P(A)+P(B)−P(A∩B) -use if problem says what is the probability that "either or happens" or "this or that happens" |
| Multiplication Rule (probability): | P(A and B)=P(A)×P(B) -use if asked "what is the probability that this and this happens" |
| When does 9:3:3:1 happen | -when genes are independently assorted (Mendelian Genetics only!) |
| Sex-linked genes: | Genes located on sex chromosomes (X or Y). Inheritance depends on the sex of the individual. |
| X-linked genes: | Located on the X chromosome. - Since males only 1 X while females have 2 Xs, males are more likely to get the disease as females can be carriers while males either have the disease or don't |
| Y-linked genes: | Located on the Y chromosome. Only males affected. |
| Describe the sex chromosomes provided by each parent during the production of haploid sex cells | Female offspring (XX):Receives one X chromosome from the mother and one X chromosome from the father Male offspring (XY): Receives one X chromosome from the mother and one Y chromosome from the father |
| Are there more X-linked or Y-Linked traits | -there are more X-linked traits so phenotypes usually come from the X chromosome. -Y chromosome has fewer genes than X chromosome so most traits come from the X and not the Y |
| Wild type (+) genotype | The “normal” or most common allele in a population Usually produces the standard phenotype (normal function) -noted as (+) |
| Mutant (c): | A variation of the gene that causes a different phenotype -less common than wild type - noted as "c" |
| SRY gene | Located on the Y chromosome Triggers male development by turning on genes that form testes Without the SRY gene female development occurs |
| How do you identify Y-linked genes on a pedigree? | Only males affected Passed father → son Appears in every generation in male line Females never show it |
| Linked genes | -Genes located on the same chromosome -Tend to be inherited together because they are physically close -The closer the genes, the less likely recombination separates them -Do not assort independently like Mendel’s genes |
| How do linked genes become unlinked form each other? | crossing over occurs during prophase I of meiosis, resulting in genes between homologous pairs switching places -thus one of the genes on one homolog ends up on another chromosome and is thus separated |
| Recombination | The exchange of genetic material between homologous chromosomes during meiosis Produces new combinations of alleles on the same chromosome |
| Recombination frequency (RF): | -Measures how often crossing-over occurs between two genes on the same chromosome -Genes that are closer to each other → lower RF -Genes that are farther apart→ higher RF (up to 50%) |
| Formula for recombination frequency | recombinants/total offspring x100 -used to map gene positons on a chromsome |
| How do you identify the recombinants in a genetics problems | - Look at the most common offspring phenotypes in a cross (they are usually the same as the parents) -Understand that any offspring showing allele combinations different from parents are recombinants -Parents: AB × ab - Recombinants= Ab or aB |
Created by:
KenechukwuIE