Chapter 11 Study Guide

What is the difference between mitosis and meiosis?

lls divide and reproduce in two ways: mitosis and meiosis. Mitosis is a process of cell division that results in two genetically identical daughter cells developing from a single parent cell. Meiosis, on the other hand, is the division 13 of a germ cell (such as sperm and egg) involving two fissions of the nucleus and giving rise to four gametes, or sex cells, each possessing half the number of chromosomes of the original cell.

What is a hybrid?

A hybrid is a offspring of crosses between parents with different traits

What are linked genes?

Genes that are inherited together with the other gene(s) as they are located on the same chromosome.

What does homozygous mean?

Homozygous refers to having identical alleles for a single trait. An allele is a form of a gene.

Why did Mendel choose pea plants to study genetics?

Mendel chose pea plants bc they can produce many offspring, they have traits that come only in 2 forms, and crosses between the plants can be controlled easily.

What is the P generation?

The "p" stands for parental. Parental generation is the first generation involving two individuals that are mated to foresee or analyze the genotypes of their offspring.

What happened to the F1 generation when Gregor Mendel crossed a tall pea plant with a short plant?

The F1 generation inherited one allele from each parent.

What is the F1 generation?

The F1 generation is the first generation of offspring produced by a set of parents. The 'F' in F1 stands for 'filial.' So in short, F1 means 'first filial generation'.

What is the F2 generation?

The F2 generation is the result of a cross between two F1 individuals (from F1 generation).

What is the end result of meiosis?

The end result is haploid cells

What is the principle of segregation?

The principle of segregation states that during gamete formation, the alleles for each gene segregate from each other, so that each gamete carries only one allele for each gene

Explain what is happening in this image.

it is crossing over

What symbol represents the number of chromosomes in a gamete?

"N" represents the number of chromosomes in a gamete.

What happens to the F1 generation generation if a heterozygous tall pea plant is crossed with a homozygous short pea plant?

50% of the F1 generation will be (Tt) yields tall plants which and 50% will be (tt) which yields short plants.

What are gametes?

A Gamete is a mature haploid male or female germ cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote. Example- egg and sperm

What are diploids?

A diploid cell is a cell that contains two sets of chromosomes. One set of chromosomes is donated from each parent.

What are regulatory genes?

A regulatory gene is any gene that REGULATES control over the expression of another gene. A regulatory gene may "silence" another gene from expressing its dominant trait.

What is a tetrad?

A tetrad is a structure containing 4 chromatids that form during meiosis

Using the Punnett Square above, what can you tell about the offspring of this cross?

All have inherited the tall trait.

What are alleles?

Alleles are different forms of a gene. They can be dominant or recessive. Some characteristics, such as eye color and the shape of the earlobe, are controlled by a single gene.

Explain how allowing the generation F1 to self- pollinate in producing the F2 generation allowed Mendel to reach his conclusion about inheritance.

Allowing the F1 pea plant to self pollinate caused the recessive phenotype to reappear in the F2 generation. Self-pollination of the F1 plants also allowed the 3:1 phenotype ratios to occur, supporting Mendel‛s theory. Self pollination showed that traits controlled by the recessive alleles could reappear in the F2 generation.

What are phenotypes?

An individual's phenotype consists of the traits we can observe. These can include features of appearance, behavior, metabolism, or anything else we can detect.

What are genotypes?

As the name suggests, a person's genotype refers to the types of genes he or she has for a particular inheritable trait.

If a pea plant‛s alleles for height are tt, what could be said about the parents?

Both carried the tt recessive allele. They both had heterogeneous alleles for height (Tt)

What are chromatids?

Chromatids are 1 of 2 identical "sister" parts of a duplicated chromosome.

When do chromosomes form tetrads?

Chromosomes form Tetrads during meiosis in Prophase I.

What is codominance?

Codominance occurs when both phenotypes produced by both alleles are clearly expressed. Such as when a red flower crosses with a white flower and instead of having either white or red flowers the flowers are white with red spots.

What are daughter cells?

Daughter cells are cells that are produced as a part of the process of cell division. Depending on whether cells are dividing in mitosis or meiosis, the daughters can be genetically identical to the parent cell or they may be different.

Which principle explains why a female bison and male bison that are both heterozygous for normal skin pigmentation (Aa) produce an albino offspring (aa).

Dominance and segregation explain why the heterozygous (Aa) parents can have an albino offspring.

How are gametes produced?

Gametes are produced by a type of cell division called meiosis. They are haploid, meaning that they contain only one set of chromosomes. When the haploid male and female gametes unite in a process called fertilization, they form what is called a zygote. The zygote is diploid and contains two sets of chromosomes.

What is a gamete?

Gametes are reproductive cells (sex cells) that unite during sexual reproduction to form a new cell called a zygote. Male gametes are sperm and female gametes are ova (eggs). Gametes are produced by a type of cell division called meiosis. They are haploid, meaning that they contain only one set of chromosomes.

What are gene maps?

Gene maps are a graphic representation of the order of genes within chromosomes by means of detailed analysis of the DNA. They are based on the frequencies of crossing over

What are haploids?

Haploid describes a cell that contains a single set of chromosomes. The term haploid can also refer to the number of chromosomes in egg or sperm cells, which are also called gametes.

Why did Gregor Mendel remove the male parts of flowers of some plants?

He removed the male parts to control the crosses between plants.

What does heterozygous mean?

Heterozygous refers to having two different alleles for a single trait

Explain why Thomas Hunt Morgan used fruit flies in his studies.

Hunt Morgan used fruit flies in his experiment bc fruit flies produce large numbers of offspring.

Explain how a trait might seem to "disappear" for a generation, and then "reappear" in the following generation.

If all of the individuals in a generation receive one dominant allele and one recessive allele, then they would all show the dominant trait. If they are bred, then they will pass on the dominant allele to some of their offspring and the recessive allele to the others. Offspring receiving 2 recessive alleles will show the recessive trait, so it will reappear.

What is incomplete dominance?

Incomplete dominance is occurs when one allele is not completely dominant over the other allele. In incomplete dominance, the heterozygous phenotype lies somewhere between the 2 homozygous phenotypes

What is independent assortment?

Independent assortment is a basic principle of genetics developed by a monk named Gregor Mendel in the 1860's. Mendel formulated this principle after discovering another principle now known as Mendel's law of segregation.

How many alleles for the height gene does a pea plant gamete have?

It has 2 alleles.

How is meiosis I different from mitosis?

Meiosis I produces 2 haploid daughter cells, but mitosis produces 2 diploid daughter cells.

What is meiosis?

Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of genetic information. These cells are our sex cells - sperm in males, eggs in females

What are multiple alleles?

Multiple alleles have more than 2 variations of a gene. An example of multiple alleles is human blood types. People can have A, B, AB or O blood types.

Looking at the Punnett Square above, what can be said about the relationship between pea shape and pea color?

Pea shape and pea color are independent of each other, they are assorted independently

What are polygenic traits?

Polygenic traits are traits that are said to be dominated by 2 or more genes. Polygenic traits often show a wide range of phenotypes. The variety of skin color in humans comes about partially bc more than 4 different genes control this trait

Explain the principle of independent assortment?

The Principle of Independent Assortment describes how different genes independently separate from one another when reproductive cells develop

Explain why short plants reappeared in the F2 generation if in the P generation, a tall plant was crossed with a short plant.

The allele for both heights segregated when the F1 plants made gametes.

A tall plant (TT) is crossed with a short plant (tt). If the tall F1 pea plants are allowed to self pollinate, the offspring what will happen?

The offspring could be tall or short. See explanation below:

How can the principles of probability be used?

The principle of probability can be used to predict the traits of offspring of genetic crosses

Use the Punnett square above to answer this question. If a pea plant that is heterozygous for round, yellow peas (RrYy) is crossed with a pea plant that is homozygous for round peas but is heterozygous for yellow peas (RRYy), how many different PHENOTYPES are their offspring expected to show?

There will only be 2 phenotypes bc all are going to be round (they are all RR or Rr which yields round shape) There is no rr which yield wrinkled shape. The only variant will be if they are yellow or green (YY and Yy yield yellow and yy yield green).

If a breed of chicken show codominance for feather color, one allele codes for black feathers and another for white feathers, what will the feathers of heterozygous chickens of this breed be?

They will be speckled bc of codominance. Neither the black or white dominates

What can you apply Mendel‛s principle of genetics to?

You can apply Mendel‛s principles to all organisms

What happens to 2 genes if they are on the same chromosome and rarely assort independently?

You can infer that they are probably close together.