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Codominance
________: Sometimes youll see an equal expression of both alleles.
female
A(n) ________ with one color blind- X is called a carrier.
Synapsis
________ involves two sets of chromosomes that come together to form a tetrad (a bivalent)
Traits
________ are influenced by one or more of your genes.
haploid
If a cell has only one set of chromosomes, we call it a(n) ________ cell.
new diploid
A parent will contribute a gamete with one set that will be paired with the set from the other parent to produce a(n) ________ cell, or zygote.
sexual reproduction
The mitochondria are always provided by the egg during ________, so mitochondrial inheritance is always through the maternal line, not the male line.
male
A(n) ________ has one X and one Y chromosome.
second meiotic division
The purpose of the ________ is to separate sister chromatids.
Polygenic inheritance
________: In some cases, a trait results from the interaction of many genes.
Punnett squares
________ are used to predict the results of a cross.
Mendel
________ crossed two true- breeding plants with contrasting traits: tall pea plants and short pea plants.
ovule
In plants the mitochondria are provided by the ________ and are maternally inherited.
Meiosis
________ is limited to sex cells in special sex organs called gonads.
Oogenesis
________ produces only one ovum, not four.
cell
A(n) ________ that has two sets of chromosomes is a diploid ________.
same chromosome
Since linked genes are found on the ________, they can not segregate independently.
spermatogenesis
During ________, four sperm cells are produced for each diploid cell.
Nondisjunction
________ can occur in** anaphase I** (meaning chromosomes dont separate when they should), or in anaphase II (meaning chromatids dont separate)
Humans
________ contain 23 pairs of chromosomes.
Non nuclear inheritance
________: Apart from the genetic material held in the nucleus, there is also genetic material in the mitochondria.
Nondisjunction chromosomes
________ failed to separate properly during meiosis.
Diploid
________ organisms usually have two copies of each gene, one on each homologous chromosome.
II
At telophase ________, a nuclear membrane forms around each set of chromosomes and a total of four haploid cells are produced.
anaphase II
During ________, chromatids of each chromosome split at the centromere, and each chromatid is pulled to opposite ends of the cell.
Barr body
A(n) ________ is an X chromosome that is condensed and visible.
sperm cells
If ________ are produced, then meiosis is called spermatogenesis.
Homologous chromosomes
________ are the same size and shape, and contain the same genes.
monohybrid cross
A(n) ________ occurs when two individuals are crossed and one gene is being studied.
Phenotypic plasticity
________ occurs if two individuals with the same genotype have different phenotypes since they are in different environments.
female cell
In every ________, one X chromosome is activated and the other X chromosome is deactivated during embryonic development.
organism
If a(n) ________ has two different alleles for a given trait, the ________ is heterozygous.
X chromosome
The ________ destined to be inactivated is randomly chosen in each cell.
chromosome
Individuals with Down syndrome have three- instead of two- copies of the 21st ________.
Sex cells
________ are haploid.
metaphase II
In ________, chromosomes move toward the metaphase plate.
identical alleles
When an organism has two ________ for a given trait, the organism is homozygous.
X inactivation
________ is the reason it is okay that females have two X chromosomes and males have only one.
Synapsis
________ is followed by crossing- over, the exchange of segments between homologous chromosomes.
females
In males, the gonads are the testes, while in ________ they are the ovaries.
Meiosis
________ is also known as gametogenesis.
Humans
________ have 23 pairs of homologous chromosomes.
homologous chromosomes
The ________ that make up each pair are similar in size and shape and contain the same genes in the same locations.
female
A(n) ________ has two X chromosomes.
Meiosis
________ is the production of gametes.
Homologous chromosomes
________ are two copies or versions of the same chromosome in a diploid cell or organism.
Meiosis
________ is likely to produce sorts of variations than is mitosis, which therefore confers selective advantage on sexually reproducing organisms.
Meiosis
________ actually involves two rounds of cell division: meiosis I and ________ II.
The three principles of genetics
the Law of Dominance, the Law of Segregation, and the Law of Independent Assortment
Mendel crossed two true-breeding plants with contrasting traits
tall pea plants and short pea plants
So far, we have looked at only one trait
tall versus short
Law of Dominance
One trait masks the effects of another trait
Law of Segregation
Each gamete gets only one of the copies of each gene
Law of Independent Assortment
Each pair of homologous chromosomes splits independently, so the alleles of different genes can mix and match
Twenty
two of the pairs of chromosomes are called autosomes
Most sex
linked traits are found on the X chromosome and are more properly referred to as "X-linked."
**Incomplete dominance (**blending inheritance)
In some cases, the traits will blend
Codominance
Sometimes youll see an equal expression of both alleles
Polygenic inheritance
In some cases, a trait results from the interaction of many genes
Non-nuclear inheritance
Apart from the genetic material held in the nucleus, there is also genetic material in the mitochondria
Meiosis actually involves two rounds of cell division
meiosis I and meiosis II
Meiosis I consists of four stages
prophase I, metaphase I, anaphase I, and telophase I
Note 
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