Mendel and Genetics Flashcards
flower
reproductive organ in most plants
petal
brightly colored, fragrant flower parts that are used to attract pollinators
sepal
leaf-like structure at the bottom of the petals of a flower that supports and strengthens the petals
pistil
female reproductive structure in flowers
stigma
sticky top of the pistil
style
slender neck of the pistil
ovary
bulb-like base of the pistil
ovule
part of the ovary that contains an egg cell
stamen
male reproductive structure in flowers
anther
top of the stamen where pollen cells are made
filament
stalk-like part of the stamen
pollen grain
male gamete in plants
pollination
the movement of pollen from the anther to the stigma
self pollination
the movement of pollen from the anther to the stigma of the same flower
cross pollination
the movement of pollen from the anther to the stigma of a different flower
pollen tube
grows and carries pollen from the stigma to the ovule after pollen lands on the pistil of a flower
**fertilization
the joining of pollen and egg
trait
the physical characteristics of an organism
hereditary
the passing of traits from parents to offspring
genetics
the scientific study of heredity
**fertilization
the joining of sperm and egg to produce a new organism
purebred
an organism that always produces offspring with the same form of a trait as the parent
selection
organisms are chosen for breeding
filial-
LATIN-means “son” or “daughter”
gene
a piece of DNA on a chromosome that affects a specific trait
alleles
the different forms of a gene
dominant
an allele whose trait always shows up in an organism
recessive
an allele whose trait only shows up when two of the alleles are present and is masked when paired with a dominant allele
hybrid
an organism that has two different alleles for a trait
DNA
deoxyribonucleic acid
the molecule that holds genetic information
homozygous
“pure” having two identical alleles at a given location
heterozygous
“hybrid” having two different alleles at a given location
probability
the likelihood that a particular event will occur
Punnett square
a chart that shows all the possible combinations of alleles that can result from a genetic cross
genotype
an organism’s genetic makeup or the actual alleles present
phenotype
an organism’s physical appearance or visible traits
co-dominance
when two different alleles exist, but neither are dominant nor recessive. Both alleles are expressed in the offspring
mixed dominance or blending
when two different alleles exist, but neither are dominant nor recessive.
The traits mix and are expressed as a third trait
multiple alleles
a gene pair for a single trait that has three or more forms of the gene
X-chromosome
female sex chromosome. Females have two X-chormosomes
Y-chromosome
male sex chromosome. Males have one Y-chromosome and one X-chromosome
carrier
an organism that has a recessive gene for a trait but does not exhibit the trait because of a dominant gene that hides it
sex-linked gene
genes that are carried on the X-chromosome
pedigree
a tool that geneticists use to trace the inheritance of traits in huans or other organisms
genetic disorder
an abnormal condition that a person inherits through genes or chromosomes and is present at conception
Cystic Fibrosis
a genetic disorder in which the body produces abnormally thick mucus that fills the lungs making it hard for the infected person to breathe
Sickle Cell Anemia
a genetic disorder that affects the red blood cells causing them to take on an irregular shape during periods when the oxygen level is low
Hemophilia
a sex-linked disorder in which a person’s blood clots very slowly or not at all
Down Syndrome
a genetic disorder caused when the 21st pair of chromosomes does not separate normally during meiosis causing the offspring to have 47 chromosomes.
sex-linked disorder
conditions and disease that are caused by genes on the x chromosome
