Genetics Test Flashcards
Study “Mitosis and Meiosis” deck
Seriously. Do it.
What is non-disjunction?
The failure of homologous chromosomes to move to opposite poles of the cell during meiosis; results in an abnormal number of chromosomes in the daughter cells
What is monosomy?
A chromosomal abnormality in which there is a single chromosome in place of a homologous pair
What is trisomy?
A chromosomal abnormality in which there are three homologous chromosomes in place of a homologous pair
What is Klinefelter’s?
A genetic disorder where the individual has two X and one Y chromosome, causing males to usually be sterile and exhibit some feminine body characteristics
What is Down Syndrome?
A chromosomal abnormality in which an individual three copies of chromosome number 21, causing developmental and intellectual disabilities
What is Turner Syndrome?
A genetic disorder in which a female has only one X chromosome and no Y, meaning she’s missing an X chromosome; do not mature sexually and are sterile
What is a karyotype?
The chromosomes of an individual that have been sorted and arranged according to size and shape; they can show genetic disorders in individuals
What is a true-breeding organism?
An organism that produces offspring that are genetically identical for one or more traits
What is a hybrid?
The offspring of two different true-breeding plants
What did Mendel do?
Mendel crossed pure breeds of plants to study what the offspring of those plants would be genetically. He discovered the first generation the dominant trait would win out completely then he discovered in the F2 generation that there would roughly be a ratio of 3 to 1 meaning for every three dominant traits there would be one recessive trait
What is an allele?
A specific form of a gene
What is homozygous?
Two of the same allele, whether dominant or recessive
What is heterozygous?
Two different alleles
What is a genotype?
The genetic makeup of an individual
What is a phenotype?
An individuals outward appearance with respect to a specific characteristic
What is a dominant allele?
The allele that, if present, is always expressed
What is a recessive allele?
The allele that is expressed only if it is not in the presence of the dominant allele
What is a trait?
A particular version of a characteristic that is inherited
What is a gene?
a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring
What is a punnett square?
A diagram that summarizes every possible combination of each allele from each parent; a tool for determining the probability of a single offspring having a particular genotype
What is a monohybrid cross used for?
Used to compare with the offspring would look like when you compare only one trait
What is a dihybrid cross used for?
Comparing two different traits
(If two dogs produce an offspring, and one has grey fur one has black fur one has a long tail and one has a Short tail, use the information of which you know is dominant and which is recessive to determine what the phenotypes and genotypes would be of the offspring)
What is incomplete dominance?
Heterozygous individuals have an intermediate phenotype (the colors are blended together to form a third color) neither are dominant because neither mask the other
What is co-dominance?
Both alleles are expressed fully to produce an offspring with a third mixed phenotype (a black rooster and a white rooster form a black and white rooster)
What are multiple alleles?
There are more than two alleles for the treat making it a combo of codominant and dominant genetic traits (like blood types)
What is a test cross?
A cross used to determine the genotype of an individual expressing a dominant trait (whether hetero or homo)
What is a pedigree?
A diagram of an individuals ancestors used in human genetics to analyze Mendelian inheritance of a certain trait; shows connections between parents and offspring, sex, and the presence or absence of a trait
What does sex-linked mean?
Describes an allele that is found on one of the sex chromosome, X or Y, and when passed onto offspring is expressed; always recessive
Describe how X-linked disorders affect each gender
If found on the X chromosome, a female has two X’s. Makes only have one (XY). The male will express the recessive allele from the mother no matter what because the Y cannot mask the effects of the allele. A female must inherit the gene from the mother and the father for it to appear, making women less susceptible
What is DNA made of? (3 things)
A sugar phosphate basebone intertwining in a double helix. Nitrogen containing base pairs spread throughout: Adenine, Guanine (purines), Thymine and Cytosine (pyrimidines) each opposing on opposite sides (T always bonds/opposites A; G always bonds with C). Between the base pairs is Hydrogen bonds, A-T makes 2 H bonds and G-C makes 3 bonds
What is DNA?
The genetic code or sequence that provides instructions on how to build proteins
What are proteins?
Long chains of amino acids that perform specific tasks for the cell or organism; they are often enzymes or structural proteins
