Part 6

the phenotype that is presented 100% of the time

traits that are masked if dominant alleles are also present

are traits Y or y

Organisms that have a pair of identical alleles for a particular gene a pea plant that is YY is homozygous dominant for seed color One that is yy is homozygous recessive for seed color

if the organism has different alleles for a gene one that is Yy is heterozygous

are the three allele pairs so YY, Yy, yy

a handle mathematical tool for predicting the phenotypes of offspring based on the gene types of the parents.

Organisms like humans are diploid, meaning that their cells contain two sets of chromosomes. We call the diploid state 2n, where n represents one set of chromosomes Cell division in a diploid organism is preceded by replication of the genome. the duplicate chromosomes are organized and then separated from one another in a cell division process called mitosis so a cell that is 2n yields two new cells and each is 2n.

The division process that produces gametes. Gamete formation requires two rounds of cell division, including two rounds of nuclear division but with only one round of DNA replication and two pairs of chromosomes are divided into pairs of chromosomes, which are separated into individual chromosomes. The results of this is haploid cells containing only a single chromosome set. SO for each special diploid cell (2n) that undergoes meiosis, four haploid gametes are formed (n + n + n + n)

it looks how a single trait is inherited when two heterozygotes are mated

a cross between parents heterozygous at two specific genes reveal the process of independent assortment the second law of inheritance is the law of independent assortment.

incomplete dominance, Codominance, Epistasis traits that do not follow patterns of inheritance and expression

Incomplete dominance is apparent because the heterozygote exhibits a phenotype that is intermediate between the two homozygous parents. so if C is chestnut color and CR is cream if the gene type is C/CR the color is diluted by the cream making it a totally different color. This is incomplete dominance

sometimes two alleles can exhibit their phenotypes equally in the heterozygote Blood type is determined by a gene that has three alleles i^A, i^B, and i the children of parents who are i^A/i^A and I^B/I^B will be I^A/I^B the i^A/i^A parent is type A, because it exhibits a particular sugar on the surface of its red blood cell and same with i^B/i^B it displays a different sugar. Their children are both type AB and exhibit both sugars. people who have type O blood have neither sugar on their red blood cells and the genotype of people with type O blood is i/i

Inheritance results from interactions among two or more genes is a type of gene interaction in which the phenotype of a trait is the result of one gene’s alleles affecting the alleles of another independently inherited gene. Black coat color dominant over chocolate so B/B or B/b and chocolate labs are b/b but there is a second gene that affects the pigment of the animals coat. the deposition gene has two alleles E and e and E is dominant. Any lab that is homozygous recessive e/e for the deposition gene will be a yellow lab, regardless of the gene type B gene. So the E gene is epistatic on the B gene. its only yellow when the deposition gene is homozygous recessive. so e/e doesnt matter what B is

Is the fundamental constituent of matter that retains the properties of an element Atoms can lose, gain, or share electrons to make a variety of chemical bonds of varying strengths and properties. atoms undergo chemical reactions by gaining or losing electrons to achieve stability. an atoms properties can be inferred by its position on the periodic table, which relates to the number of valence electrons in its outermost shell

the atoms of each element have distinct configurations that give the element unique chemical and physical properties, but all atoms are composed of the same three fundamental particles: protons, neutrons, and electrons Where an element is represented on the periodic table is indicative of its number of protons, valence shell configuration, and chemical and physical properties

the elements that make up the majority of living organism are carbon, hydrogen, oxygen, and nitrogen Every element has its own characteristic identity that determines how it will interact with other elements and these chemical properties depend on the structure of an elements smallest unit, the atom.

Contains three primary types of components: electrons, protons, and neutrons

are negatively charged subatomic particles that move around the center of the atom in regions known as orbitals each orbital can hold two electrons and orbitals group together to make up a shell.

within shells, orbitals are arranged into subshells labeled s,p,d and F where s subshells are closest to the nucleus. the number of orbitals and shells that an element’s atom contains depends on the number of electrons within the atom

Electrons in an atoms’s outermost shell are valence electrons and include the electrons involved in bonding between atoms.

in the center of the atom, the atomic nucleus are subatomic particles without a charge

Subatomic particles that are positive and are also located in an atom’s nucleus