Studied by 22 peoplewelcome back, study this on multiple choice and answer with definition u can do true or false if u want but it's lowk a waste of time for me also study HOW TO DO dihybrid crosses, pedigrees, and punnett squares and how to read them, learn more abt mendel too js incase (if u have time) and rlly memorize ur ratios for phenotypes and genotypes (especially for dihybrid crosses) go over codon ciphers as well and use your handouts in class to understand better what the different enzymes do in dna replication and how it looks in a diagram, lastly, look back at ur notes and in class handouts. good luck!!!
Gregor Mendel manipulated the fertilization of peas and studied results of crosses for different traits. Pea flowers are ___-___________ so Mendel was able to control which plants were able to breed by mixing the pollen of a flower with the ___ of another. He prevented cross pollination by removing _______.
7, self-pollinating, egg, anthers
What is the P generation?
The parental generation of a cross
What is the F1 generation?
The offpsring of the parent generation
What is the F2 generation?
The offpsring of the F1 generation
Alleles
The different forms of genes
Trait
A specific characteristic that varies from one individual to another
Gene
Structure or sequence of DNA
The relationship between alleles, genes, and traits
Genes are the “base” of the code for a trait of something and alleles are the different versions and types of it that provide uniqueness to the trait.
Homozygous
2 copies of the SAME allele
Heterozygous
2 different alleles
Genotype
The “code” or genetic makeup of a trait
Phenotype
The physical appearance of a trait
Gametes
Sex cells
Zygotes
Fertilized egg cells
Mendel’s Principle of Heredity
Genes come in pairs and are inherited as distinct units, one from each parent
Mendel’s Principle of Dominance
Some alleles are dominant and some alleles are recessive. The dominant traits mask or hide the recessive and are in capital letters. Recessive traits are in lowercase and hidden but are still there.
Mendel’s Principle of Segregation
Each parent gives one allele to their offspring because alleles separate during gamete formation.
Mendel’s Principle of Independent Assortment
Traits are passed independently from each other. No TWO traits are connected to each other.
Complete Dominance
When the dominant allele complete masks the recessive allele
Co-Dominance
When there are two dominant alleles that both show
Incomplete Dominance
When two different dominant alleles blend.
Multiple Alleles
More than two alleles
allows for more than 2 phenotypes or different variations of a phenotype
Example of Multiple Alleles
Blood Types
Co-dominance
Polygenic Traits
Many genes interact to determine one trait; also allows for many possible phenotypes
Example of Polygenic Traits
Skin, hair, height and eye color
What things influence an organism’s phenotype?
The genotype, allele, and genes
TRUE OR FALSE: When alleles segregate from each other, they join.
False, seperate
Coat color in rabbits is determined by a single gene that has multiple alleles.
False, Polygenic Traits
Probability
the likelihood that a particular event will occur
The principle of independent assortment states that _______ for different traits can segregate independently during the formation of gametes.
alleles
How many recessive alleles for a trait must an organism inherit in order to show that trait?
2
The principles of probability can be used to…
predict the genotype and phenotype of of an offspring of genetic crosses
Pedigrees use the present generation to…
track the flow of traits within a family and determine the past
Squares in Pedigrees
Genetically Male
Circles in Pedigrees
Genetically Female
Horizontal Line in Pedigrees
Mating/married
Break in the middle of a horizontal line in pedigrees
Divorced
Remarried relationships will be on ________ sides in pedigrees
opposite
Adopted offspring will be in ________ in pedigrees
brackets
Vertical Line in pedigrees
Biological children
Pedigrees go in order of birth from…
left to right
Shaded shape pedigrees
Affected trait
Non-shaded shape in pedigrees
Unaffected trait
Slash line on shape in pedigrees
Deceased
Autosomal Recessive Traits
Disorders found when two recessive alleles are present and located on Autosomes (body chromosomes). These traits can skip generations.
Autosomal Dominant Traits
Disorder characterized by dominant alleles located on Autosomes (body chromosomes). They are shown in every generation and usually affects most individuals. Homozygous dominants cannot survive, expressed individuals are heterozygous.
Sex-Linked Traits
AKA X-Linked Traits, Disorders found on the sex chromosomes (determine sex traits). More commonly found in males since they do not have a second X chromosome to mask the trait.
Order you display your genotypic ratio
Homozygous Dominant: Heterozygous : Homozygous Recessive
Order you display your phenotypic ratio
Looks Dominant : Looks Recessive
How would you calculate the percent probability of a genotype or phenotype from a cross?
Multiply by ½
Pedigrees observe the _____types in generations while Punnett squares observe the ____types in generations.
pheno-, geno-
Autosome
The first 22 pairs of chromosomes
Sex chromosomes
The 23rd pair of chromosomes
Sperm
Male gametes
Eggs
Female gametes
Meiosis is ______, not in a cycle.
linear
Meiosis is a _________ division
reduction
Homologous chromosomes
A set of chromosomes (one from the female and one from the male) that serve the same function.
Homologous chromosomes have the same:
length
centromere position
carry genes that control the SAME inherited traits
matching set, one is from mom one is from dad
Sister Chromatids
Identical copies of the same chromosome
Diploid Cell
A cell that contains a both sets of homologous (one from the female and one from the male) chromosomes.
Diploid cells are expressed as…
2N
Haploid Cell
A cell that contains ONE set of chromosomes
Haploid cells are expressed as…
N
Meiosis
The process of making HAPLOID cells (gametes) from a DIPLOID cell
Interphase I
Chromosomes replicate to make sister chromatids
Prophase I
The chromosomes pair with Homologous chromosomes and form a tetrad at the chiasma. Crossing over occurs.
Tetrad
A structure that contains 4 chromatids ( a set of 2 from each parent)
Crossing Over
Exchange of genetic material between chromosomes occurs
Crossing over is important because…
it creates genetic variance by creating new combinations of alleles.
Metaphase I
Homologous chromosomes line up at the equator
Anaphase I
Homologous chromosomes separate
Telophase I
The cell divides creating two haploid cells. Ends with Cytokinesis.
When meiosis II begins, the cells are haploid but have _ copies of sister chromatids.
Two
The second division of Meiosis must occur to…
allow sister chromatids to separate from each other before forming gametes
Prophase II
Sister chromatids prepare to separate
Metaphase II
Sister chromatids line up at the equator
Anaphase II
Sister chromatids separate from each other
Telophase II
The cells divide
Cytokinesis II
4 genetically different, haploid cells are formed
Spermatogenesis
Gamete formation for males. Development of sperm from a diploid cell.
In males meiosis occurs from puberty until
death
Oogenesis
Gamete formation for females. Development of an egg from a diploid cell.
In females meiosis I occurs in the…
fetal stage
In females, meiosis II occurs at
puberty
Nondisjunction
Chromosomes fail to seperate during meiosis, resulting in abnormal chromosome numbers in gamete
Autosomes are paired with _______ chromosomes and are ordered based on ____
homolog, size
Klinefelter Syndrome
Klinefelter syndrome is when a male gets an extra X chromosome resulting from nondisjunction (47,XXY).
Klinefelter syndrome can affect…
Physical and intellectual development. Most commonly, affected individuals are taller than average are unable to father biological children (infertile)
How to write shorthand
# of chromosomes, sex chromosomes, (location of abnormal chromosome)
Turner syndrome
A chromosomal disorder (due to nondisjunction) in which a female is born with only one X chromosome. Written as 45, X.
Symptoms of Turner Syndrome
Short stature, delayed puberty, infertility, heart defects, and certain learning disabilities
Treatment for Turner Syndrome
Treatment involves hormone therapy. Fertility treatment may be necessary for women who want to become pregnant.
Down Syndrome
A chromosomal abnormality characterized by the presence of an extra copy of genetic material on chromosome 21 due to nondisjunction. Written as (47, XY +21).
The effects of the extra copy in Down Syndrome varies differently from…
individual to individual, genetic background, environmental factors, and random chance.
Mitosis (cell cycle)
To make genetically identical copies of diploid cells
Chiasma
Where crossing over occurs
Polar Bodies
Small haploid cells that are formed at the same time as an egg cell during oogenesis, but do not have the ability to be fertilized
AB Blood Type is a universal
recipient
O Blood Type is a universal
donor
Note
Flashcard