Genetics ch.12 Flashcards
genetics
scientific study of hereditary
trait
specific characteristic of an individual
hybrid
offspring of crosses between parents with different traits
gene
sequence of DNA that codes for a protein and determines a trait
allele
different form of a gene
principle of dominance
Mendel’s second conclusion, which states some alleles are dominant and sone are recessive
segregation
separation of alleles during gamete formation
gamete
sex cell
What are four reasons why pea plants are important to study?
they are self pollinating, have different easily recognizable traits, had male and female parts, and are easy plants to take care of
How did Mendel cross-pollinate flowers?
Mendel took pollen from one plant and put in onto another plant
probability
likelihood that a particular event will occur
homozygous
two identical alleles for a certain gene
heterozygous
two different alleles for a certain gene
phenotype
physical characteristics of an organism
genotype
genetic of an organism
Punnett Square
diagram that can be used to predict the genotype and phenotype combinations of a genetic cross
independent assortment
one of Mendel’s principles that states that genes for different traits can segregate independently during the formation of gametes
incomplete dominance
Situation in which one allele is not completely dominant over another allele
Codominance
A condition in which neither of two alleles of a gene is dominant or recessive.
multiple alleles
three or more forms of a gene that code for a single trait
three or more forms of a gene that code for a single trait
traits controlled by two or more genes
multifactorial
Referring to a phenotypic character that is influenced by multiple genes and environmental factors.
Genome
the complete instructions for making an organism, consisting of all the genetic material in that organism’s chromosomes
Karyotype
A display of the chromosome pairs of a cell arranged by size and shape.
sex chromosomes
Chromosomes that determine the sex of an individual
Autosomes
Any chromosome that is not a sex chromosome
sex-linked gene
gene located on a sex chromosome
Pedigree
A diagram that shows the occurrence of a genetic trait in several generations of a family.
Name 4 ways Mendel’s work is unique
he completed his work in a short amount of time, he developed three principles of inheritance, he created F1 and F2 generations and continued to study, and he discovered the formation of gametes.
Name 4 ways the pea plant is important to the study of genetics
The pea plant is important to study in genetics because they have easily identifiable traits, they are easy to grow, they are self-pollinating, and produce offspring with similar traits.
What is the difference between the Law of segregation and the Law of Independent assortment?
The law of segregation states that every individual possesses two alleles and only one allele is passed on to the offspring. Whereas the law of independent assortment states that the inheritance of one pair of genes is independent of the inheritance of another pair.
How did Mendel control the mating of pea plants?
- male parts removed
- pollen from other plants placed on female carpel
3.seeds collected and planted to give F1 generation
What is the difference between a gene and an allele? Give an example of each
A gene is a section of DNA that encodes to make a certain trait like how a mother has blond hair and so does the child whereas an allele is just a variant form of a gene an example of this is the color in flowers.
monohybrid cross
A cross between individuals that involves one pair of contrasting traits
dihydrid cross
crossing organisms differing in two characters
Codominant cross
With codominance, a cross between organisms with two different phenotypes produces offspring with a third phenotype in which both of the parental traits appear together.
X-linked crosses
crosses that involve traits on the X chromosome
What is an example of a polygenic trait?
height, skin color, weight
The different forms of a gene are called
allele
Gregor Mendel removed the male parts from the flowers of some plants in order to
control self pollination
If an pea plant alleles for height are tt, what is true of its parents
Both parents were heterozygous
When you flip a coin, what is the probability of it being tails?
50%
A heterozygous tall pea plant is crossed with a short plant. The probability that an offspring plant will be tall is
25%
Organisms that have two identical alleles for a particular trait are said to be
homozygous
What principle states that during gamete formation genes for two different traits will separate without influencing each other’s inheritance?
Mendel’s law of independent assortment
Gregor Mendel’s principles apply to
traits in plants and animals
A breed of chickens shows codominance for feather color. One allele codes for black feathers, another codes for white feathers. The feathers of heterozygous chicken’s of this breed will be
speckled
Variations in human skin color, weight, and height are examples of ______ and can result in a bell curve pattern of inheritance
polygenic traits
What percentage of human sperm cells carry an X chromosome
50%
A human female inherits
an X chromosome from their father, and the other X chromosome from their mother
How many chromosomes are shown in a normal human karyotype?
46 chromosomes
If a couple had three children all girls what is the probability they will have a boy?
50%
A female whos father was colorblind marries a normal male. What is the probability that their child will be colorblind?
50%
A white flower crossed with a red flower producing a pink flower is an example of
incomplete dominance
Which combination of sex chromosomes results in a male human being?
1 X and 1 Y chromsome
