Bio 102, unit 2 Flashcards
Holds that chromosomes are the structures that physically contain genes.
Chromosome Theory of Inheritance
Proposed Chromosome Theory in 1903.
Walter Sutton & Theordore Boveri
Each matched pair of chromosomes, one obtained from each parent.
Homologues
All chromosome characteristics in the body or a representation of.
Karyotype
Chromosomes that determine gender of the individual; XY in males, XX in females.
Sex chromosomes
All other chromosomes besides sex chromosomes.
Autosomes
A single strand of replicated chromosome.
Chromatid
Specialized region on each chromosomes where both sister chromatids are attached.
Centromere
Structure attached to centromere where fibers from mitotic spindle connect.
Kinetochore
Having two different sex chromosomes, such as XY in human males.
Heterogametic
Heritable change in alleles due to substitution, insertion, or deletion of nucleotides.
Mutation
T/F: Mutations are usually dominant.
F
If mutation is on sex chromosome, the father’s allele will not be passed with the Y chromosome to which gender of offspring?
Male
If an allele is on the X chromosome, female offspring will have the same phenotype as which parent?
Paternal
If an allele is on the X chromosome, male offspring will have the same phenotype as which parent?
Maternal
Inheritance of traits located on the X chromosome.
Sex linkage, or X-linkage
Three Sex-linked Traits in Humans
Baldness, color blindness, hemophilia
Having one or more genes that have no allele counterparts, such as on the X chromosome.
Hemizygous
Inactivated X chromosomes in mammalian females.
Barr bodies
Any cell that is not or will not become a gamete.
Somatic cell
Idea proposed by Mary Lyon that mammalian females inactivate one or the other X chromosome in each somatic cell during early embryogenesis.
Lyon Hypothesis
Type of inheritance in which heterozygotes fully express both alleles.
Co-dominance
Example of co-dominance in humans.
Blood type
Condition where neither allele is dominant over the other. Heterozygous individuals express an intermediate phenotype.
Incomplete Dominance
Genes that have more than two alleles; results from different mutations of the same gene.
Multiple alleles
Expression of one gene masked by expression of another gene.
Epistasis
T/F: Phenotype and pigmentation can be affected by environment.
True
Occurs when a trait is controlled by several gene pairs; usually results in continuous variation.
Polygenic Inheritance
A genotype with multiple phenotypic effects; a single gene effects more than one trait.
Pleiotropy
Example of pleiotropy in humans.
Sickle-cell anemia, produces multiple consequnces
Condition in which inheritance of a particular gene is coupled with that of a specific chromosome.
Linkage
Occurs during meiosis when chromatids exchange parts with other chromatids, resulting in new combinations.
Recombination
Process in which part of a chromatid is physically exchanged with another chromatid; results in new allele combinations.
Crossing-over
Mutation where order of genes is reversed on a chromosome segment.
Inversion
Mutation where a gene is added into an existing sequence.
Insertion
Mutation that produces and extra copy of a chromosome segment without altering number of chromosomes.
Duplication
Mutation where segments of a chromosome are lost or removed.
Deletion
Phases of Mitosis
Prophase, metaphase, anaphase, telophase, interphase
T/F: During mitosis, one round of nuclear division produces two identical cells.
T
Two rounds of sexual division that produces 4 gametes (1n) which are not identical.
Meiosis
Point of contact where two homologous, non-sister chromatids exchange genetic material during crossover in meiosis.
Chiasmata
Condition in which an organism has at least one extra copy of a chromosome.
Polysomy
Condition in which an organism has three copies of a chromosome instead of two.
Trisomy
Condition in which an organism has only one copy of a chromosome instead of two.
Monosomy
Monosomy in which the female has only one X chromosome.
Turner’s Syndrome
Autosomal trisomy 21
Down’s Syndrome
Trisomy in which males have an extra X chromosome, XXY.
Klinefelter Syndrome
Where does meiosis occur?
Testes or ovaries
