Biology Quarter 2 Exam

welcome 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