Chapter 14: Terms
Chapter 14 flashcards
| Dominant allele | When one allele is expressed over the other alleles present. |
| Generative nucleus | Nucleus in the immature male gametophyte that will later divide by mitosis to produce two sperm cells. |
| Genes | Hereditary units consisting of a sequence of DNA that occupies a specific location on a chromosome (locus) and determines a particular characteristic in an organism. Genes undergo mutation when their DNA sequence changes. |
| Genotype | Genetic composition of an organism, including chromosomes of the nucleus and the DNA in chloroplasts and mitochondria. |
| Heritability | Measurement of a quantitative trait that passes from parent to offspring and is measured in high and low; high being similar between parent and offspring and low being dissimilar between parent and offspring. |
| Heterozygote | Plant with two different alleles of a particular gene and giving rise to varying offspring; offspring are generally more vigorous than offspring from homozygote. |
| Homozygote | Plant with identical alleles of a particular gene; gives rise to identical, or nearly identical, offspring. |
| Integument | Cells that form the ovary wall. Nucellus cells on the interior of the ovule wall develop into megaspore mother cells. |
| Linkage | When two genes are on the same chromosome. |
| Locus | Location on a chromosome where a particular gene is found. |
| Megaspornatium | Place in the ovary where the female gametophyte will be formed. |
| Mendel’s First Law — the law of segregation | Principle that during gamete formation each member of the allelic pair separates from the other member to form the genetic constitution of the gamete; e.g., Ss diploid produces S and s gametes. |
| Mendel’s Second Law — the law of independent assortment | Principle that during gamete formation the segregation of the alleles of one allelic pair is independent of the segregation of the alleles of another allelic pair. |
| Microsporangium | Place in the anther where the male gametophyte will be formed. |
| Phenotype | Physical appearance of an organism; expressed as Phenotype = Genotype + Environment |
| Punnett square | Simple database used to visualize the types of zygotes and their expected frequency that form from male and female gametes. |
| Qualitative differences | Large differences that can easily be seen or measured in qualitative terms; e.g. fruit color. |
| Quantitative differences | Small differences that are measured numerically; e.g. yield in kg/ha. Can be influenced by the environment. |
| Recessive allele | Allele(s) that are not expressed if a dominant allele is present; will be expressed if there is no dominant allele. |
| Suspensor | Produced by multiple mitotic cell divisions of the embryo’s basal cell; the suspensor anchors the apical cell of the embryo to the ovule wall. |
| Synergid cells | Cells flanking the egg cell in the mature female gametophyte. |
| Tube nucleus, or vegetative nucleus | Nucleus in the male gametophyte that is associated with pollen tube growth. |
