Chapter 11

Section 1


Objectives:

• Describe Griffith's experiments and conclusion.
• Describe Avery's experiments and conclusion.
• Explain how experiments with viral DNA further supported Avery's conclusion.

1. Describe Griffith's experiments and conclusion.

He injected four mice with four different strains of bacteria. One strain was pneumonia, one strain was harmless, one strain was heated pneumonia, and the last one was a mixture of the heated pneumonia strain and the harmless bacteria. The strain of pneumonia and the mixture of the heated pneumonia and the harmless bacteria killed the mice. The harmless strain alone, and the heated pneumonia had no affect on the mouse. 

2. Describe Avery's experiments and conclusion.

Avery treated Griffith's mixture of the heat treated pneumonia and the harmless bacteria with protein-destroying enzymes. Bacterial colonies in the mixture were still transformed. Then he treated the mixture with DNA-destroying enzymes. The colonies failed to transform. He concluded that DNA was the genetic material of the cell. 

3. Explain how experiments with viral DNA further supported Avery's conclusion.

Two scientists, Hershey and Chase, knew that the bacteriophage (phage) had two basic components: DNA inside, and the proteins were on the outside. They conducted the following experiment:

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Section 2

Objectives:

• Identify the building blocks of DNA.
• Describe DNA's structure and the rules for base pairing in DNA. 

1. Identify the building blocks of DNA.

Nucleotides are really the building blocks of DNA. They are monomers that make nucleic acid polymers. Each nucleotide has three parts: 

1. Deoxyribose, a ring shaped sugar.
2. A phosphate group.
3. A nitrogenous base.

2. Describe DNA's structure and the rules for base pairing in DNA. 

DNA is a double-helix made up of nitrogenous bases. The rules of base pairings are so:

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Section 3


Objectives:

• Explain how the template mechanism is important in DNA replication.
• Describe the process of DNA replication.

1. Explain how the template mechanism is important in DNA replication.

The template mechanism is important because it provided a basis for how the DNA molecule replicates.

2. Describe the process of DNA replication.

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Section 4


Objectives:

• Explain the "one gene–one polypeptide" hypothesis.
• Trace the information flow from DNA to protein.
• Describe how amino acids are coded.

1.  Explain the "one gene–one polypeptide" hypothesis.
The function of an individual gene is to dictate the production of a specific protein.


2. Trace the information flow from DNA to protein.
DNA first must convert into RNA, or ribose nucleic acid. RNA is slightly different than DNA, because it has uracil instead of thymine, and its sugar is ribose, not deoxyribose. After the DNA is converted to RNA, it goes through a process called transcription, when a DNA template is used to produce a single-stranded RNA molecule. After the RNA is transcribed, nucleic acid information is converted to amino acid information. 


3. Describe how amino acids are coded.
They are coded using the triplet code.

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Section 5


Objectives:

• Describe the process of DNA transcription.
• Explain how an RNA message is edited.
• Describe how RNA is translated to a protein.
• Summarize protein synthesis. 

1. Describe the process of DNA transcription.

Messenger RNA (mRNA) is transcribed to the DNA template. It is similar to the process of DNA replication, but only one of the DNA strands is used as a template. Then, the DNA strands separate at the location of transcription. Finally, RNA nucleotides pair up with DNA nucleotides using a transcription enzyme called RNA polymerase.


2. Explain how an RNA message is edited.
Introns are removed from the RNA, and the exons are joined together, right before it leaves the nucleus. It produces a mRNA molecule with a continuous coding sequence. It is now ready for translation. 


3. Describe how RNA is translated to a protein.

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4. Summarize protein synthesis.
DNA is a template, which controls the transcription of the mRNA. The mRNA show the order of amino acids in a polypeptide, which is constructed with the help of tRNA and rRNA. Lastly, the proteins control the function of the cell.  


Section 6


Objectives:

• Describe the types of mutations that can affect genes.
• Explain what can cause a mutation.

1. Describe the types of mutations that can affect genes.
There are two types of mutations that can affect genes: substitutions and insertions/deletions. A substitution is when a base or nucleotide is switched to another. It may affect a protein. An insertion/deletion is when either an extra base is added or removed. This is mutation is more harmful, because of errors made in chromosome crossovers.


2. Explain what can cause a mutation.
DNA replication or when errors are made in chromosome crossovers. There are also environmental factors, such as radiation, that can cause mutations.

Chapter 10

Section 1


Objectives:

• Compare and contrast the blending hypothesis and the particulate hypothesis of inheritance.
• Describe the methods Mendel used in his plant-breeding experiments.

1. Compare and contrast the blending hypothesis and the particulate hypothesis of inheritance.

Both the blending hypothesis and the particulate hypothesis believe that traits are inherited from the parents. In the blending hypothesis, scientists believed that different traits from parents would blend to create the offspring traits. For example, if a red flower was crossed with a white flower, the offspring would be pink, and so would its offspring. The particulate hypothesis believed that parents pass traits that are "separate and distinct factors" to their offspring , which are "responsible for inherited traits". Mendel thought that these factors would be the same generation after generation.

2. Describe the methods Mendel used in his plant-breeding experiments.
He bred pea plants for seven years. One of his methods included tying a little cloth bag around the flowers that way pollen from other plants couldn't fertilize it. He also crossed true-breeding plants to test the particulate hypothesis.

Section 2


Objectives:

• Explain Mendel's principle of segregation.
• Describe how probability applies to genetics.
• Contrast genotype and phenotype.
• Explain Mendel's principle of independent assortment.

1. Explain Mendel's principle of segregation.

"Two alleles for a character segregate during the formation of gametes, so that each gamete carries only one allele for each character. The union of gametes during fertilization reforms allele pairs in the offspring"

2. Describe how probability applies to genetics.

You can use probability to "predict particular outcomes if you know the genetic make-up of both parents".

3. Contrast genotype and phenotype.

A phenotype is an observable trait, while a genotype is the "genetic make-up,or combination of alleles".

4. Explain Mendel's principle of independent assortment.

It states that during gamete formation in an F2 cross, a particular allele for one character can be paired with either allele of another character.

Section 3

Objectives:

• Describe how alleles interact in intermediate inheritance.
• Describe inheritance patterns involving multiple alleles.
• Explain how polygenic inheritance can result in a wide range of phenotypes.
• Describe how environmental conditions affect phenotype expression.

1. Describe how alleles interact in intermediate inheritance.
In some organisms, neither allele is dominant. This pattern doesn't support the blending theory, because parent phenotypes can reappear in the F2 generation.

2. Describe inheritance patterns involving multiple alleles.
One pattern involving multiple inheritance is codominance. Codominance is when the heterozygote expresses both traits. It shows the traits of both alleles.

3. Explain how polygenic inheritance can result in a wide range of phenotypes.
Polygenic inheritance is when two or more genes affect a single trait. The more genes that affect a single character, the more possible phenotypes.

4. Describe how environmental conditions affect phenotype expression.
Temperature, nutrition, exercise, illnesses, and exposure to sunlight are environmental factor that could affect phenotype expression.

Section 4


Objectives:

• Summarize the chromosome theory of inheritance.
• Explain how genetic linkage provides exceptions to Mendel's principle of assortment.

1. Summarize the chromosome theory of inheritance.

Genes are located on chromosomes, and the behavior of chromosomes during meiosis or fertilization accounts for the inheritance patterns.

2. Explain how genetic linkage provides exceptions to Mendel's principle of assortment.

If two genes are on the same chromosome, they will not be separated, or assorted, and therefore there will be less variation.

Section 5

Objectives:

• Explain how sex-linked genes produce different inheritance patterns in males and females.
• Explain why most sex-linked disorders are more common in males.

1. Explain how sex-linked genes produce different inheritance patterns in males and females.
Sex-linked genes are located on the X chromosome, so females carry two copies of the gene for the trait, and males carry one.

2. Explain why most sex-linked disorders are more common in males.

Sex-linked disorders are more common in males because if the male receives a trait just from the mother, then he will have the disorder. In females, they must receive the trait from both their parents, which is rare.

9.5 and 9.6

Section 5


Objectives:

• Describe how homologous chromosomes are alike and how they differ.
• Contrast haploid and diploid cells.
• Summarize the process of meiosis.

1. Describe how homologous chromosomes are alike and how they differ.

Homologous chromosomes are similar in the fact that they carry the same sequence of genes controlling the same characteristics. One difference is that they have different forms of the same gene. One might have the traits for brown eyes and the other for blue.

2. Contrast haploid and diploid cells.

Diploid cells carry two homologous sets of chromosomes (the exceptions are egg and sperm). A cell with a single set of chromosomes is a haploid cell. They are produced through meiosis. 

3. Summarize the process of meiosis.

Interphase 1: The cell duplicates the DNA.

Prophase 1: Proteins cause the homologous chromosomes to stick together (tetrads). Tetrads attach to the spindle . Sister chromatids in the tetrads exchange genetic information (crossing over).

Metaphase 1: Tetrads move across the middle and line up across the spindle. 

Anaphase 1: Homologous chromosomes separate and move to opposite sides of the spindle.

Telophase 1 and Cytokinesis: The nuclear envelope reforms as chromosomes are in opposite poles, and the cell starts to separate.

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Prophase 2: A spindle forms, attaches to centromeres, and chromosomes are moved to the middle of the cell.

Metaphase 2: Chromosomes line up in the middle, attached to the spindle.

Anaphase 2: Sister chromatids separate and move to opposite ends.

Telophase 2 and Cytokineis: Chromatids arrive at the ends, and the cells are split one more time.

Section 6

Objectives:

• Describe how chromosome assortment during meiosis contributes to genetic variation.
• Explain how crossing over contributes to genetic variation.
• Compare and contrast mitosis and meiosis. 

1. Describe how chromosome assortment during meiosis contributes to genetic variation.

The way chromosomes line up is at random, so the assortment that ends up in cells is completely by chance.  Four combinations are possible for each chromosome, but there are 8 million combinations for the entire cell.

2. Explain how crossing over contributes to genetic variation.

Crossing over can produce a new chromosome that contains new combination of genetic material from different parents. 

3. Compare and contrast mitosis and meiosis.