Unit 2: The Cell



Unit 4: Heredity

Standard B-4: The student will demonstrate an understanding of the molecular basis of heredity.

This unit is all about HEREDITY. It will be comprised of two parts:

Part I: Meiosis and Genetics Part II: DNA and Genetic Technology

I. Chromosomes I. DNA

II. Meiosis II. DNA to Protein

III. Mendelian Genetics III. Mutations & Genetic Engineering

Unit 4, Part 1 Test: _________ Unit 4, Part 2 Test: __________

DNA, Genes, and Chromosomes

Objectives:

Summarize the relationship among DNA, genes, and chromosomes.

Recall the basic structure of chromosomes and genes.

Illustrate or interpret an illustration of the relationship of a chromosome, DNA, and genes using words or diagrams.

Vocabulary Words:

Define the following vocabulary words in the space provided.

1. Chromosome

2. DNA

3. Gene

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What are genes?

Genes are located on ________________ in the cell’s _______________. Chromosomes are long threads of ________ tightly coiled.

Each organism must inherit a single copy of every gene from both of its ____________.

When an organism produces its own gametes, those 2 sets of genes must be separated from

each other so that each gamete contains just one set of __________.

Chromosomes and Information

Objectives:

Explain how DNA functions as the code of life and the blueprint for proteins.

Compare autosomes and sex chromosomes.

Differentiate between body cells and gametes.

Compare haploid cells and diploid cells.

Vocabulary Words:

Define the following vocabulary words in the space provided.

1. Somatic cell

2. Gamete

3. Homologous chromosome

4. Autosome

5. Sex chromosome

6. Diploid

7. Haploid

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How many chromosomes do organisms have?

|Organism |Body Cell (2n) |Sex Cells (n) |

|Fruit fly |8 |4 |

|Garden pea |14 |7 |

|Corn |20 |10 |

|Tomato |24 |12 |

|Leopard Frog |26 |13 |

|Apple |34 |17 |

|Human |46 |23 |

|Chimpanzee |48 |24 |

|Dog |78 |39 |

|Adder’s tongue fern |1260 |630 |

Diploid vs. Haploid

Cells can either have a full set of chromosomes ( _________) or half a set of chromosomes (___________). The __________ number is always an even number.

|Diploid Cells |Haploid Cells |

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| |Represented by “N”. |

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|Cells that have both sets of homologous chromosomes. | |

| |In humans, the haploid number is 23. |

| |N = 23 |

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|Found in body cells, called somatic cells. | |

| |Undergo the process of Meiosis |

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Meiosis

Objectives:

Summarize the phases of meiosis I and meiosis II.

Illustrate and interpret scientific diagrams of the phases of meiosis.

Compare meiosis I and meiosis II.

Compare mitosis and meiosis with regard to processes and outcomes.

Explain the effect of crossing over on the genetic variation in daughter cells.

Vocabulary Words:

Define the following vocabulary words in the space provided.

1. Meiosis

2. Gametogenesis

3. Sperm

4. Egg

5. Polar body

6. Zygote

Read page 173 in your textbook and answer the following questions.

1. What is the difference between homologous chromosomes and sister chromatids? ______________________________________________________________________________________________________________________________________________________

2. What connects two sister chromatids? ____________________________________________

3. How are sister chromatids made? ________________________________________________

4. When are homologous chromosomes divided? _____________________________________

5. When are sister chromatids divided? _____________________________________________

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Now, let’s look at pages 174-175 in your textbook.

Haploid gametes (________ and _______) are produced from diploid cells through a process called ______________.

• 2N ( N

• A process of reduction division in which the number of _____________ per cell is cut in half through the __________ of homologous chromosomes.

• There are 2 distinct phases: ______________ and _______________

• Look at figure 6.5 in your textbook.

In the space below, list the phases of Meiosis in order from the beginning.

What happens during each phase?

Interphase Prophase I

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Metaphase I Anaphase I Telophase I

Prophase II Metaphase II Anaphase II Telophase II

Read page 176 in your textbook and answer the following questions.

1. What is the end result of meiosis? ________________________________________________

2. What is gametogenesis? _______________________________________________________

3. What is the female gamete? ____________ Male? _____________

4. How many sperm are formed? __________________

5. How many eggs are formed? _________________ What else is formed? _________________

Gamete Formation

The process of making sperm is called ___________________________. Each time this happens, 4 sperm are made. Each sperm is not genetically identical.

The process of making an egg is called ____________________. Each time this happens, 1 egg and 3 polar bodies are formed.

Males are born with _________________ that turn into ______________ once puberty happens.

Females are born with _______________ that turn into _____________ once puberty happens.

In males, this process will continue his entire lifetime.

In females, this process will continue until she goes through menopause. This happens later in life, and means that females can no longer get pregnant.

In females, if an egg does not get fertilized, a woman has to get rid of it. The way she gets rid of it is through ________________. This happens once a month from puberty until menopause.

|Mitosis |Meiosis |

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Mendelian Genetics

Objectives:

Predict inherited traits by using the principles of Mendelian Genetics.

Identify traits as homozygous or heterozygous, dominant or recessive.

Infer the possible genotypes and phenotypes of offspring.

Illustrate monohybrid and dihybrid crosses.

Summarize the Mendelian concepts of independent assortment, segregation and dominance.

Compare the genotypes and phenotypes of offspring to their parents.

Vocabulary Words:

Define the following vocabulary words in the space provided.

1. Trait

2. Genetics

3. Purebred

4. Cross

5. Law of segregation

6. Gene

7. Allele

8. Homozygous

9. Heterozygous

10. Genome

11. Genotype

12. Phenotype

13. Dominant

14. Recessive

15. Punnett square

16. Monohybrid square

17. Testcross

18. Dihybrid cross

19. Law of independent assortment

20. Probability

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Genetics is the study of HEREDITY.

When Gregor Mendel studied pea plants in the 1800s, he knew nothing about genetics. Today, genetics is a big field of science. Every day we are learning more about how genes work. The hope is that one day we will have enough knowledge and technology to diagnose, treat, prevent, and even cure certain genetic disorders.

Read pages 177-179, and complete the following:

1. _______ are the distinguishing characteristics that make each organism a little different.

2. We study heredity through the field of ___________.

3. The Father of Genetics, __________ ________, was actually a ___________, not a biologist who bred thousands of plants, carefully counting and recording his results.

4. Mendel didn’t know anything about chromosomes and meiosis, however he correctly ___________ the results of meiosis long before chromosomes were discovered.

5. Mendel worked in the garden at a __________, where he was a monk.

6. Mendel made three key choices about his experiments. They were: _____________________, _________________, and ____________________________________________________.

7. Why did Mendel choose to work on pea plants? ____________________________________

8. In nature, pea plants self-pollinate because they contain both male and female parts. If allowed to self-pollinate enough times, the line of pea plants would become uniform, or ____________.

9. How did Mendel cross-pollinate two different pea plants? ______________________________________________________________________________________________________________________________________________________

10. How many traits did Mendel decide to observe in his experiments? _________ Why did he chose these traits only? ________________________________________________________

11. In genetics, when two organisms mate, we call it a ________________.

12. Look at Figure 6.9 on page 178. Why did the white flower not appear in the F1 generation? __________________________________________________________________________________________________ Why did it reappear in the F2 generation? ______________________________________________________________________________________________________________________________________________________

13. Mendel drew three conclusions about heredity through his experiments. What were they?

a.

b.

c.

*Letters B and C, collectively are called Mendel’s first law or __________________________.

Read pages 180-182, and complete the following.

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Match the following words with their definition to the right.

_____ homozygous a. the allele that is always expressed

_____ gene b. refers to the physical characteristics

of the offspring (tall or short)

_____ heterozygous

c. two of these make up a gene

_____ allele

d. the allele that is always masked

_____ dominant

e. all of an organisms genes

_____ genotype

f. refers to the actual genes an

_____ recessive organism has (TT or Tt)

_____ phenotype g. two alleles that are the same; TT or tt

_____ genome h. a piece of DNA that codes

for a protein

i. two alleles that are different; Tt

The Law (Principle) of Dominance states:

For each genotype, indicate whether it is homozygous or heterozygous.

AA __________ TT __________ Tt __________

Pp __________ pp __________ Gg __________

Ss __________ yy ___________ Rr __________

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For each of the genotypes below determine what phenotypes would be possible. 

|Purple flowers are dominant to white flowers. |Yellow peas are dominant to green peas. |

|PP __________________ |YY ________________ |

|Pp __________________ |Yy ________________ |

|pp __________________ |yy ________________ |

|Round seeds are dominant to wrinkled seeds. | |

|RR __________________ |Tall plants are dominant to short plants. |

|Rr __________________ |TT _________________ |

|rr __________________ |Tt _________________ |

| |tt __________________ |

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For each of the phenotypes, list the possible genotypes. Remember to use the letter of the dominant trait.

|Green pods are dominant to yellow pods. |Smooth pods are dominant to wrinkled pods. |

|____ green pods |_____ smooth |

|____ green pods |_____ smooth |

|____ yellow pods |_____ wrinkled |

The Law (Principle) of Segregation states:

The Law (Principle) of Independent Assortment States:

This law holds true unless genes are _________, meaning they are close together on the same chromosome and tend to be inherited together. The principles of Mendelian Genetics can be used to predict the inherited traits of offspring. A ____________ ___________ can be used to predict the probable genetic combinations in the offspring that result from different parental allele combinations that are independently assorted.

There are two types of crosses we will discuss in biology: __________ and ___________

|Monohybrid Cross |Dihybrid Cross |

|TT x tt |TTRr x ttRR |

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Let’s practice some Punnett Squares.

Exceptions to Mendelian Genetics

Objectives:

Describe patterns of inheritance in sex-linked traits.

Describe different types of allele interactions.

Explain how linkage maps can be used to estimate distance between genes.

Vocabulary Words:

Define the following vocabulary words in the space provided.

1. Sex-linked genes

2. Incomplete dominance

3. Codominance

4. Polygenic trait

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Read pages 200-203 and complete the following about Chromosomes & Phenotype

1. Gene expression is often related to whether a gene is located on an _________________ or on a __________ _______________.

2. _________ ______________ determines an organism’s sex but ________________ do not play a direct role in sex determination.

3. Many human genetic disorders are also caused by _____________ __________________

4. The genes that affect your hair texture are ___________ genes.

5. Many human ______________ _____________ are caused by autosomal genes.

6. Is a carrier homozygous or heterozygous? _______________

7. _________________________ genetic disorders are far less common than recessive disorders.

8. The expression of __________ on the __________ chromosomes differs from the expression of ____________ genes.

9. Genes located on the sex chromosomes are _______ _________ genes.

10. Genes on the _______ chromosome are responsible for the development of male offspring. The ______ chromosome has much more influence over _____________.

Read pages 204-207 and complete the following on the Complex Patterns of Inheritance

1. __________________ __________________ occurs when a heterozygous phenotype is somewhere between the two homozygous phenotypes. Give an example and describe the cross

2. Alleles show _____________________ in which both traits are fully and separately expressed. ______ and ______ blood types are an example of _____________________.

3. This trait is also considered a ____________ ____________ trait.

4. A pair of co-dominant alleles or multiple alleles can produce ______ different phenotypes.

5. Traits produced by two or more genes are called ___________ traits. What are two examples?

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Read pages 210 - 214 and complete the following on Gene Linkage

1. If genes are considered to be linked, it means that they were ___________ together on the same chromosome.

2. Both _________ and ___________ can be carriers of an autosomal disorder

3. Only ____________ can be carriers of _________ __________ disorders.

4. An example of a historical sex-linked disorder is called _________________

5. Which offspring would have the hemophilia and which would be the carrier?

6. An example of a sex-linked trait is ________ ________ colorblindness.

Unit 4, Part 1 Test

DNA vs. RNA

Objectives:

Compare DNA and RNA.

Recognize the chemical names of the DNA and RNA molecules.

Identify the three parts of a nucleotide.

Interpret an illustration of a nucleotide.

Interpret an illustration of a DNA and a RNA molecule.

Vocabulary Words:

Define the following vocabulary words in the space provided.

1. Bacteriophage

2. Nucleotide

3. Double helix

4. Base pairing rules

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Discovery of DNA

The scientist ____________ ____________ did a series of experiments on bacteria that caused the sickness ____________.

He discovered a process called ____________.

Did he know exactly what was transforming?

In 1944, ___________ _____________ repeated Griffiths work.

He wanted to determine which molecule in the bacteria was actually transforming. He discovered that __________ was the transforming principle that Griffith had noticed.

Conclusive evidence that DNA was the transforming principle came in 1952 from two American biologists, ____________ ___________ and _____________ _____________. They studied ___________, which are viruses that affect bacteria by taken over their DNA.

Structure of DNA

DNA stands for _________________ _______________.

The picture to the right is a ___________. It is composed of

3 parts:

The only difference between nucleotides within a DNA molecule are its nitrogen-containing bases. Therefore, there can be _______ different nucleotides within DNA.

DNA has to be responsible for three things in living things:

1.

2.

3.

The backbone of the DNA molecule is formed by ___________ and __________. The “rungs” of the DNA molecule are composed of the ____________ __________.

What do you notice about the arrangement of the DNA molecule that makes it a uniform width?

The bonds found within the DNA molecule are different. Label the bonds in the picture to the right.

Scientists Who’s Work Contributed to the Identifying the Structure of DNA

_____________ ______________ discovered that in any sample of DNA, the amount of ___________ = __________ and the amount of ____________ = ______________. This is known as the rules of base pairing. Because of this, the DNA molecule always maintains a uniform __________.

In the early 1950s, ______________ ____________ used x-ray diffraction to get information about the structure of DNA. She suggested it was __________ in nature.

_____________ ______________ and ______________ _______________ built the first model of DNA. They used Franklin’s pictures to help them construct it. They ultimately discovered that DNA was actually a __________ __________.

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In the space below, sketch a DNA molecule. Make it 3 bases in length.

Structure of RNA

RNA stands for _______________ ________________.

The picture to the right is a ___________. It is composed of

3 parts:

The only difference between nucleotides within a RNA molecule are its nitrogen-containing bases. Therefore, there can be _______ different nucleotides within RNA.

What do you immediately notice as a difference between the bases of RNA and DNA?

The rules of base-pairing still apply in RNA:

___________ = _____________

____________ = ____________

RNA is single stranded instead of double stranded like DNA.

There are three types of RNA:

1.

2.

3.

RNA is made from DNA in a process called _____________.

Let’s Compare DNA and RNA

|DNA |RNA |

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DNA Replication and Protein Synthesis

Objectives:

Summarize the role of DNA as the code of life.

Summarize the process of DNA replication.

Interpret illustrations of the processes of transcription, translation, and protein synthesis.

Compare the processes of transcription and translation.

Sequence the steps of transcription and translation.

Explain the significance of each step to the overall process of protein synthesis.

Vocabulary Words:

Define the following vocabulary words in the space provided.

1. Replication

2. DNA polymerase

3. Central dogma

4. RNA

5. Transcription

6. RNA polymerase

7. Messenger RNA (mRNA)

8. Ribosomal RNA (rRNA)

9. Transfer RNA (tRNA)

10. Translation

11. Codon

12. Stop codon

13. Start codon

14. Anticodon

15. Peptide bond

DNA Replication

The double helix structure explains how _________________can occur.

The two strands of DNA are _______________. This means one strand can be used to make a __________ of the other strand.

Before a cell can fully divide, the ________ must first be copied:

The two strand of the DNA ___________.

Two new complementary strands are made via ________ __________.

This occurs during ___ phase of the cell cycle.

In ________ DNA replication starts at one point in the chromosome and proceeds in two directions until the entire chromosome is replication.

In __________, DNA replication starts at hundreds of places along the chromosome and proceeds in either direction until the entire chromosome is copied.

Enzymes first “________” the old strands of DNA.

This process involves a lot of proteins/enzymes.

The primary enzyme involved is _____ ___________.

PRACTICE/REVIEW

1. What would be the complimentary DNA strand to the following nucleotide sequence?

A T C C G A T T A G G C C C A T A C G

2. What is the first step in DNA replication?

3. What enzyme matches the bases of free nucleotides to the bass on the parent strand?

4. If the DNA double helix were a twisted ladder, what would the sides be composed of?

5. If the DNA double helix were a twisted ladder, what would the rungs be composed of?

6. Fill in the following chart.

|Nucleotide Base |Abbreviation |Complementary Base |

| |T | |

| |C | |

| |A | |

| |G | |

In living things, there is a one-way flow of information from DNA ( Proteins. This is called Central Dogma. Proteins are made in essentially two main steps:

➢ Transcription

➢ Translation

Transcription

___________ is the process of copying DNA into RNA.

So that translation can happen next. It happens in the _________ of eukaryotes and the ____________ of prokaryotes. Wherever the ______ is. The enzyme _______ ________ binds to DNA at promoter regions & separates the strands. It then uses one strand of DNA as a _________ to make RNA. The RNA made is actually _________. Uses base-paring: A=U G=C

Transcribe the following DNA strands:

A – G – G – T – A – C – C – C – G – A – A – T – T - T

G – G – C – C – A – A – T – T – A – A – T – T – G – C

Once the mRNA is formed, it will leave the nucleus (of a eukaryote) and go the ribosome, where the second part of protein synthesis takes place, ______________.

Translation

Proteins are made (____________) by joining amino acids into long chains called ___________.

This is called ____________ _____________.

The language of mRNA is called the ___________ ____________.

Comprised of the letters A, U, C and G

Every combination of three letters is called a _________.

The genetic code (one is example is show to the right) is read _______ letters at a time. These _____ letters are referred to as a ________.

Underline the codons in the following strand of mRNA: UCGCACGGU

What amino acids do those codons code for? ____________ ------- ___________ ------___________

The bonds that link amino acids together are called ________ ________.

How many possible codons are there in the genetic code? ___________

What is the “Start Codon”? ____________ What amino acid is it? _________________

What are the 3 “Stop Codons”? ________, ___________, ________

Figure out the amino acid sequence coded for by the following DNA: TACGCATGGAAT

How does translation actually occur?

There are many steps to the actual process of translation. The process of translation actually One major molecule in this occurs on the _________.: process is the ________ molecule:

➢ mRNA is made from ________

➢ mRNA comes out of the __________ and attaches to a ____________.

➢ __________ brings in an ____________ that is complementary to the mRNA codon sequences. With each __________ is the _________ _________ that the mRNA codon codes for.

*Codon is AUG, the anticodon is UAC bringing methionine with it to attach to mRNA.

➢ __________ chain grows until it reaches a stop codon.

Mutations & Genetic Engineering

Objectives:

Compare the consequences of mutations in body cells with those in gametes.

Recall the causes of mutations.

Classify mutations as resulting from sex cell or somatic cell alterations.

Classify mutations as genetic or chromosomal.

Interpret a pedigree with regard to the nature of specific traits within a family.

Exemplify ways that introduce new genetic characteristics into an organism or a population.

Recognize types of genetic engineering and selective breeding.

Summarize the purposes of the various types of genetic engineering and selective breeding.

Compare selective breeding and hybridization.

Summarize the benefits & drawbacks of the types of genetic engineering & selective breeding.

Vocabulary Words:

Define the following vocabulary words in the space provided.

1. Mutation

2. Point mutation

3. Frameshift mutation

4. Mutagen

5. Clone

6. Genetic engineering

7. Recombinant DNA

8. Transgenic

9. Genomics

10. Human Genome Project

11. Gene therapy

12. Artificial selection (selective breeding)

MUTATIONS

In the space below, write an example of a mistake that you have made in your life.

________________________________________________________________________________________________________________________________________________________________

Mistakes are common. Some turn out good while others turn out not so good. Mutations are the same. Some mutations result in a negative aspect, while others turn out to be advantageous to the organism.

Mutation:

Mutations can occur in many ways:

□

□

□

Mutations may or may not be passed to offspring. It depends on the type of cell.

|Mutations in Gametes |Mutations in Somatic Cells |

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There are two types of mutations: _____________ mutations and __________________ mutations

Gene Mutations

The two types of Gene Mutations are Point and Frameshift.

Chromosomal Mutations

The four types of Chromosomal Mutations are Deletion, Duplication, Inversion and Translocation.

Nondisjunction is when homologous chromosomes fail to separate during meiosis. ___________ ______________ may arise from mutations in sex cells (gametes).

Are all mutations bad?

In some cases mutations are ______________ to

organisms. ________________ ______________ are

changes that may be useful to organisms in different

changing environments. These mutations result in

phenotypes that are favored by natural selection and

increase in population. An example may be

______________________________________.

Pedigrees

By examining a ____________, geneticists can identify the likelihood of an individual inheriting a genetic disorder. It is a chart constructed to show the ___________ pattern of a disorder within a family over multiple generations.

Why are there not more mutations?

______________ are factors such as radiation, chemicals, UV light, etc. that can cause changes in DNA. Some are natural and others are man-made.

Genetic Engineering

Since ALL living things use _______ as their genetic material, it is possible to __________ DNA from one species to another, either through a cross if the organisms are of the same species, or through ____________ _________ if the organisms are dissimilar.

____________ ______________ is the process of ___________ specific genes in an organism in order to ensure that the organism ______________ a desired trait.

Genetic engineering is accomplished by taking specific genes from one organism and placing them _______ another organism.

Genetic engineering can only occur when scientists know __________ where particular genes for particular traits occur on specific chromosomes.

○ A ______ ______ shows the relative location of each known gene on a chromosome.

○ __________ refers to all the genetic material in an organism. The Human Genome Project that _________ the DNA sequence of human genes is useful in ____________ genes for specific traits.

In __________, an identical copy of a gene or an entire organism is produced. Cloning brings ___________ such as organ transplants or saving endangered species, but it may also result in an organism with genetic disorders or health problems.

In______ ________, scientists insert a normal gene into an absent or ________ gene. Once

inserted the normal gene begins to produce the ________ protein or enzyme, eliminating the

cause of the __________. However, gene therapy has had limited success because the host often rejects the injected genetic material.

_______ _______ are undifferentiated cells that have the potential to become specialized in

structure or function. Primarily found in _________, they are also found all over the adult

human body (for example bone marrow) but may be harder to isolate. Therapy using stem

cells can replace tissue that is deficient due to disease or damage.

Results of genetic engineering may include:

○ Plants that manufacture natural insecticides, are higher in protein, or spoil more slowly.

○ Animals that are bigger, are faster growing, or are resistant to disease.

○ Bacteria that produce hormones such as human insulin or human growth hormone.

○ In humans, it is theoretically possible to transplant copies of normal genes into the cells of

people suffering from genetically carried diseases such a Tay-Sachs disease, cystic fibrosis,

and sickle-cell anemia.

Selective Breeding

____________ __________ is the method of ___________ selecting and breeding only organisms with a desired trait to produce the next generation. Almost all domesticated animals and most crop plants are the result of selective breeding.

Once the breeder has successfully produced offspring with the desired set of characteristics, _____________ (crossing individuals who are closely related) continues.

○ The drawback to this method is that ____________ gene defects often show up more

frequently after several generations of inbreeding.

_______________, which is another form of selective breeding, is the choosing and breeding organisms that show strong expression for two different traits in order to produce offspring that express both traits.

Recombinant DNA

___________ ____________ is taking the genes out of one organism and placing them in the genome of another in order for that organism to express that gene. This method is often ________ than selective breeding and only requires ______ generation. Also, the results are more predictable.

Genetically Modified Foods

___________ __________ foods are foods that have been ___________ altered. Foods that are NOT genetically modified are considered _____________, meaning they are natural.

One good thing about GM foods is:

A bad thing about GM foods is:

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Standard B-4: The student will demonstrate an understanding of the molecular basis of heredity.

Indicator B – 4.2: Summarize the relationship among DNA, genes, and chromosomes.

A gene is a section of _______ in a specific region of a specific chromosome.

Genes code for specific _________ to be produced, which cause specific characteristics in living things.

There are ________ and __________ forms of a gene.

Each chromosome consists of hundreds of __________ determining the many proteins for an individual organism.

Standard B-4: The student will demonstrate an understanding of the molecular basis of heredity.

Indicator B – 4.3: Explain how DNA functions as the code of life and the blueprint for proteins.

The picture to the left shows all the chromosomes in a human. It is called a ______________.

There are two types of chromosomes:

__________________ and _______ _________________

What is the difference between the two types of chromosomes?

Humans have ____ chromosomes.

____ from the male parent and ___ from the female parent

Each set of chromosomes is _____________. This means that each of the _____ chromosomes from the male parent will “match” up with each of the ____ chromosomes from the female parent. They are considered _____________ ____________.

The picture to the left is of ____________ _______________ because _____________________________________________

____________________________________________________________________________________________________.

Is there any correlation between an organisms size and its number of chromosomes? _______

Do animals have more chromosomes than plants? ___________

Is the diploid number always an even number? ___________

Sex Chromosomes and Sex Determination

1. In humans, sex is determined by which two chromosomes? _______ _____________

2. Are these chromosomes homologous? __________

3. Which pair are they? ________________

4. What percent of sperm carry the X chromosome? _________

5. What percent of egg carry the X chromosome? _________

6. What percent of sperm carry the Y chromosome? _________

7. If you have XX, the offspring will be ______________.

8. If you have XY, the offspring will be ________________.

9. Which parent determines the gender of the offspring? ___________

Standard B-4: The student will demonstrate an understanding of the molecular basis of heredity.

Indicator B – 4.5: Summarize the characteristics of the phases of meiosis I & meiosis II.

Why Meiosis?

Gametes don’t actually divide.

________________ and _______________ will divide.

The diploid number is a species remains the same.

Meiosis reduces 2N to N, then N + N = 2N.

Crossing over happens during ___________________.

This is when chromosomes exchange pieces of DNA in

order to create variety among offspring.

Standard B-4: The student will demonstrate an understanding of the molecular basis of heredity.

Indicator B – 4.6: Predict inherited traits by using the principles of Mendelian genetics (including segregation, independent assortment, and dominance).

Look at the picture to the left. Within a chromosome, DNA is found. On that DNA, there are different genes. Each chromosome has certain genes that are found only on that chromosome. Since you have two sets of chromosomes, one set of those genes came from your mother, while the other set came from your father. The combination of those genes determines what the organism looks like.

Genotype refers to the actual genes involved.

Phenotype refers to the physical trait of the organism, or, in other words, what those genes make the organism look like.

For example, if the genotype is Tt, the offspring will be tall.

“Tt” is called the genotype and “tall” would be the phenotype. Using this information, complete the following.

Standard B-4: The student will demonstrate an understanding of the molecular basis of heredity.

Indicator B – 4.7: Summarize the chromosome theory of inheritance and relate that theory

to Gregor Mendel’s principles of genetics.

Standard B-4: The student will demonstrate an understanding of the molecular basis of heredity.

Indicator B – [pic] |-"tuvwº»½¾Úß[?]

' ôéÞÐÀ³¨›‘‡zmzbRÞRD:‡‘:h*,¬OJ[?]QJ[?]^J[?]h¢K&h¢K&5?OJ[?]QJ[?]^J[?]-h¢K&h¢K&5?>*[pic]OJ[?]QJ[?]^J[?]ht[pic]e5?OJ[?]QJ[?]^J[?]h¢K&ht[pic]eOJ[?]QJ[?]^J[?]h¢K&h¢K&OJ[?]QJ[?]^J[?]h¢K&OJ[?]QJ[?]^J[?]ht[pic]eOJ[?]QJ[?]^J[?]h*,¬ht[pic]eOJ[?]QJ[?]^J[?]h*,¬OJ[?]QJ[?]\?^J[?]h4.1: Compare DNA and RNA in terms of structure, nucleotides, & base pairs.

Standard B-4: The student will demonstrate an understanding of the molecular basis of heredity.

Indicator B – 4.3 : Explain how DNA functions as the code of life and the blueprint for proteins.

Indicator B – 4.4: Summarize the basic process involved in protein synthesis.

Standard B-4: The student will demonstrate an understanding of the molecular basis of heredity.

Indicator B – 4.8: Compare the consequences of mutations in body cells with those in gametes.

Indicator B – 4.9: Exemplify ways that introduce new genetic characteristics into an organism or

a population by applying the principles of modern genetics.

Monosomy or Trisomy Disorders

Klinefelter’s Syndrome in males

Turner Syndrome in females

Down Syndrome in males or females

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