Genetik
Codominance-
The phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate ways.
polygenic inheritance-
Occurs when one characteristic is controlled by two or more genes.
Incomplete dominance-
The phenotype of heterozygotes is intermediate between the phenotype of individual homozygous for either allele.
Law of segregation-
Alleles for a single gene segregates during meiosis
Helicase-
An enzyme that untwists the double helix of DNA at replication forks, separating the two strands and making them available as template strands
Okazi fragments-
Short segment of DNA, synthesized away from the replication fork on a template strand during DNA replication.
DNA polymerase-
An enzyme that catalyzes the elongation of new DNA by the addition of nucleotide to the 3- end of an already existing chain.
Centromers
A region of duplicated chromosomes where the sister chromatids are most closely attached to each other. Microtubules of the mitotic spindle attach to structures on the chromosome. Required for proper segregation.
Meiosis-
Essential for sexual reproduction. A process where a single cell divides twice to produce four cells containing half the original amount of genetic information. Recombination of genetic material occurs here. There is meiosis I and II
Gametes-
the four haploid cells produced at the end of meiosis.
Prophase I-
The first stage of mitosis in which the chromatin condenses into discrete chromosomes visible with a light microscope. The mitotic spindle begins to form and the nucleolus disappears but the nucleus stays intact. Here crossing over occurs.
Genetic variation-
Differences among individuals in the composition of their genes or other DNA sequences.
Genetic variation sources-
Mutation, recombination, independent assortment, fertilization, gene flow.
Mutation-
Change in the DNA sequence of an organism.
Recombination-
Rearrangement of DNA sequences by breaking and rejoining chromosomes or chromosome segments.
Fertilization-
The union of two gametes.
Why don't genetic variations change the phenotype-
Many mutations occur in non-coding DNA or are silent mutations.
Natural selection-
Individuals that have a certain inherited trait will survive and reproduce at a higher rate than other individuals of the trait. For example the giraffe's long neck.
Clinical heterogeneity-
Mutations in the same gene can lead to different clinical diseases or symptoms.
Monogenic inheritance (One)-
A single gene inheritance. A single trait or disorder that is controlled by a single gene. Follow Mendelian rules
Multifactor inheritance (many)-
Multifactor inheritance (many)- Polygenic and environmental factors. A trait or disorder from multiple genes and environmental factors. Does not follow Mendelian rules.
Continuous replication-
occurs in the leading strand, DNA polymerase adds nucleotides continuously in the 5’ -3’ direction toward the replication fork. Only one RNA primer is needed
Discontinuous replications-
Discontinuous replications- Occurs on the lagging strand that goes away from the replication fork, replication occurs in short fragments (okazaki fragments) and these are later joined by the enzyme DNA ligase. Multiple RNA primers are needed.
RNA primers-
RNA primers- Initiate DNA synthesis
Chiasmata-
Chiasmata- Physical sites where crossing over occurs between homologous chromosomes. This becomes visible during prophase I.
What are the chromosomal makeup of each daughter cell after telophase and meiosis-
The cells are haploid and the chromosomes are each composed of two chromatids.
Hardy equilibrium conditions-
Hardy equilibrium conditions- No mutations, random mating, no gene flow, no genetic drift and no natural selections.
Sexual selections
Individuals with certain inherited characteristics are more likely to obtain mated than other individuals of the same sex. There is intrasexual and intersexual.
Intersexual-
One sex chooses based on the traits in the other sex.
Intrasexual-
competition between same sex
Bottleneck effect
a type of a Genetic drift, occurs when the size of the population is reduced by natural disasters or human actions.
Epistasis-
A type of gene interactions in which the phenotype expression of one gen alters another one.
Pleiotropy-
one single gene that can have multiple effects
DNA primase-
Catalyzes the synthesis of short RNA molecules used as primers for DNA polymerase
DNA polymerase III-
Responsible for bacterial chromosomal DNA replication.
Prometaphase-
second stage of mitosis, the nuclear envelope fragments and the spindle microtubules attach to kinetochores of the chromosomes.
Metaphase-
Third stage of mitosis, the spindle is complete and the chromosomes attached to microtubules at their kinetochores are all aligned at the metaphase plate.
Anaphase-
Fourth stage of mitosis, chromatids of each chromosome have separated, the daughter chromosomes are moving to the poles of the cell.
Telophase-
Fifth stage of mitosis daughter nuclei are forming and cytokinesis has begun.
Independent assortment-
Homologous chromosome pairs line up randomly during metaphase I, and each pair's orientation is independent.
Homologous pair-
Pair of chromosomes of the same length. Here homologous chromosomes that carry information for the same trait pair up during prophase I. Have one pair from each parent.
Autosomal chromosomes
are the 22 numbered pairs humans have
Meiosis I-
The first division of cell division. Separates homologous chromosomes and ends with 2 haploid cells.
Meiosis II-
Second division of cell division. Separates sister chromatids and ends with four different haploid cells which results in haploid daughter cells with genetic variations.
Meiosis vs mitosis-
Homologous chromosome pairs in meiosis but not in mitosis.
What is the relationship between recombination frequency and physical disaster between genes on chromosomes-
The closer the two genes are the lower the recombination frequency.
Gene flow-
the transfer of alleles from one population to another. This results in the movement of fertile individuals of their gametes. Example pollen from a population of flowers is carried by the wind to another population of flowers nearby, resulting in new alleles in this population.
Gene pool-
The combination of all the genes present in a population or species. This can happen in any population, for example in birds the gene pool includes all the alleles for all the traits present in the bird.
Mutation types-
Detection, duplication, inversion, translation.
Hereditary material-
Can be copied, can hold information, can acquire mutations.
Founder effect-
when a part of a population leaves and starts a new population.
Allele frequency-
a measure on how a common an allele are in a population.
Genetic drift-
random change in the allele frequency that happens by chance
Mitosis-
A process of nuclear division in eukaryotic cells. Somatic cells are divided here.
RNA splicing-
Introns are cut out from the primary mRNA transcript and exons are joined to make mature mRNA.
Missense mutations-
change the amino acid sequence and we get a change in the protein.
Sister chromatics-
One half of a duplicated chromosome. Two sister chromosomes are identical copies of each other.
Codon and anticodon-
Codon is the set of 3 mRNA bases and anticodon is a set of 3 bases on tRNA.
Allele-
A version of an gene, you inherit one from each parent
Phenotype-
Observable traits.
Adaptive evolution-
When a population changes over time because some traits help individuals survive and reproduce better.