Wake-up Explain the difference between photosynthesis and cell respiration in terms of carbon dioxide. What would happen if there were no nitrogen-fixing bacteria?

EOC Review #4: Genetics, Meiosis, and Biotechnology

Meiosis

A sequence in DNA that codes (has the directions) for a trait. What is a Gene? A sequence in DNA that codes (has the directions) for a trait.

What is a Homologous Pair? A pair of chromosomes with similar genes; one chromosome is from your mom and the other from your dad

Diploid? Formula: 2n n = the number of chromosomes 2 = two chromosomes; homologous pairs are present -Normal number of chromosomes in organisms body cells

Haploid? Formula: n n = the number of chromosomes -Single set of unpaired chromosomes (no homologous pairs) found in gametes.

Reproductive cell; Sex cell Males have sperm and females have eggs What is a Gamete? Reproductive cell; Sex cell Males have sperm and females have eggs

Brief summary of Meiosis Process in which gametes (sex cells) are made Need to split apart the homologous pairs; reduce # of chromosomes by 1/2

DNA is Replicated Homologous Pairs

Homologous Pairs are separated Sister Chromatids are separated Process: Meiosis Homologous Pairs Meiosis I Homologous Pairs are separated Meiosis II Sister Chromatids are separated

Process: Fertilization Combination of the egg an sperm Zygote Homologous Pairs

Meiosis produces four gametes (sex cells) with HALF the number of chromosomes of the original cell

If an organism has 50 chromosomes and it undergoes meiosis, how many chromosomes will be present in the new cells?

Exchange of parts between two paired chromosomes Crossing Over Exchange of parts between two paired chromosomes

Meiosis and Crossing Over

Law of Independent Assortment Homologous chromosomes will separate independently of each other during meiosis

What is the Benefit of Sexual Reproduction/Meiosis? Increases Genetic Variation

Mendelian Genetics

DOMINANT allele: Expressed trait; Capital letter, Always first

Recessive Allele recessive allele: Only expressed if paired with another recessive; Lowercase letter

What is genotype? Combination of alleles; allele letters that code for a trait; GENETIC makeup of gene

a. Homozygous Dominant: Two dominant alleles Types of Genotypes a. Homozygous Dominant: Two dominant alleles BB

b. Homozygous Recessive: Two recessive alleles Types of Genotypes b. Homozygous Recessive: Two recessive alleles bb

c. Heterozygous: One dominant and one recessive allele Types of Genotypes c. Heterozygous: One dominant and one recessive allele Bb

What is phenotype? Physical expression of trait; observable characteristic; physical appearance

Monohybrid Crosses Christopherson

Tool used to predict the genotypes and phenotypes of offspring Punnett Square Tool used to predict the genotypes and phenotypes of offspring

What is Monohybrid Cross? Punnett square using only one trait.

If purple is dominant and white is recessive, cross a purebred (homozygous dominant) purple flower with a white flower. X PP pp

PP x pp p p P Pp Pp P Pp Pp

Example #1 A male that is heterozygous for purple hair is crossed with a orange haired woman. Orange is recessive. What chance to they have in producing a purple haired child? Orange haired child?

Example #3 A couple is heterozygous for the gene for big nose. They are about to have a child and hope that it has a small nose. Do they have a chance? How much of a chance? B = Big nose and b = small nose

Special Crosses: Incomplete Dominance and Codominance

What is Incomplete Dominance? Blending of the dominant and recessive alleles in heterozygous 3rd phenotype

Plant: Snapdragons White: r or R` or W Red: R

Pink: Rr or RR` or RW

What is Codominance? Both dominant and recessive alleles are expressed in heterozygous 3rd phenotype

Chickens: Feather Color Black: B White: b

Black and White: Bb

In snapdragons, red flowers are dominant over white flowers In snapdragons, red flowers are dominant over white flowers. The heterozygous genotype has pink flowers. Cross a homozygous red-flowered plant with a pink flowered plant. What are the chances of producing white flowers? (R = red and r = white)

In certain cattle, hair color can be red (homozygous RR), white (homozygous rr), or roan (a mixture of red and white hairs, heterozygous Rr). When two roan cattle mate, what genotypes and phenotypes of offspring could be obtained?

Multiple Alleles and Sex-linkage

What are Multiple Alleles? Three or more alleles for a particular gene

Example: Blood Types

Different Blood Types in Humans Blood Type A IAIA IAi

Different Blood Types in Humans Blood Type B IBIB IBi

Different Blood Types in Humans Blood Type AB IAIB

Different Blood Types in Humans Blood Type O ii

A man with heterozygous A blood marries a woman that is heterozygous B blood. What blood types will their kids have?

What are Sex-linked Traits? Alleles that are attached to the sex chromosomes

Tricky thing about the Y chromosome The Y chromosome does not hold any alleles

A woman who has hemophilia marries a normal male A woman who has hemophilia marries a normal male. They are worried about their children having hemophilia. Should they worry? Explain.

If a man with normal color vision marries a woman who is a carrier for colorblindness, what is the probability of their having a color-blind son? A color-blind daughter?

Karyotypes Christopherson

There are _________ chromosomes in a typical human body cell.

There are _________ homologous pairs within these cells.

What are Sex Chromosomes? Chromosomes that determine the sex of an organism

Typical Female Sex Chromosomes

Typical Male Sex Chromosomes

Autosomes: Any chromosome that’s not a sex chromosome 22 pairs of Autosomes

What is a Karyotype? Number and appearance of chromosome set

Understanding a Karyotype Homologous pairs Autosomes Sex Chromosomes

Failure of the chromosomes to separate properly during meiosis Nondisjunction Failure of the chromosomes to separate properly during meiosis

1 instead of 2 chromosomes Monosomy Gamete Gamete Mono – One Missing a chromosome 1 instead of 2 chromosomes Zygote

Turners Syndrome XO-Single X chromosome

Having an extra chromosome Trisomy Gamete Gamete Tri – Three Having an extra chromosome 3 instead of 2 chromosomes Zygote

There is an extra 21st chromosome Down Syndrome Aka: Trisomy 21 There is an extra 21st chromosome

Human Genetic Disorders and Pedigrees Christopherson

Diagram showing a family tree and patterns of inheritance. What is a Pedigree??? Diagram showing a family tree and patterns of inheritance.

Recessive Trait or Disorder Traits or disorders caused by 2 recessive alleles

Cystic Fibrosis Disease that causes the body to produce unusually thick, sticky mucus that: Clogs the lungs and leads to lung infections Obstructs the pancreas Stops natural enzymes from helping the body break down and absorb food

Types of Pedigrees: Recessive Present/Affected Genotypes: bb Absent/Unaffected Genotypes: BB or Bb HINT: Recessive Disorders skip generations

Generation I-III was skipped

Sex-Linked Trait/Disorder Traits/disorders linked to sex chromosomes

Inability to see colors in the normal way Color Blindness Inability to see colors in the normal way

Inability of the blood to clot properly Hemophilia Inability of the blood to clot properly

Types of Pedigrees: Sex-linked Present/Affected Genotypes: XbXb or XbY Absent/Unaffected Genotypes: XBXB or XBXb and XBY HINT: Mainly males are affected

Notice the number of males with the trait.

Dominant Trait or Disorder Traits or disorders caused by a dominant allele Affected individuals are homozygous dominant or heterozygous

Huntington’s Disease Causes the break down of brain cells, (neurons) in certain areas of the brain. Causes uncontrolled movements, loss of intellectual faculties, and emotional disturbance.

Types of Pedigrees: Dominant Affected Genotypes: BB or Bb Unaffected Genotypes: bb

What type of inheritance?

What type of inheritance?

What type of inheritance?

Genomes and Genetic Engineering Christopherson

The complete set of genetic material of an organism Genome (Video - 0:28-2:29) The complete set of genetic material of an organism

Human Genome Project (24:42- The sequence of the 3 billion base pairs (A,T,G,C) in human DNA was discovered. This means that the sequence of the genes within our DNA is known

Benefits of the Human Genome Project Improve diagnosis of diseases and help with early detection of genetic disorders

Gene Therapy -Swapping an abnormal gene for a normal one -Repairing an abnormal gene

What is Genetic Engineering? Technology used to change the DNA of organisms to create a new useful result

How is Genetic Engineering possible?

1. Isolate Gene Specific “gene of interest” can be “cut” out of DNA using restriction enzymes

Enzyme produced by bacteria; cut DNA at specific base sequences. Restriction Enzymes Enzyme produced by bacteria; cut DNA at specific base sequences.

2. Place the Gene of Interest into Vector Vector = Vehicle that “carries gene of interest”; Bacteria is the most common.

2. Place the Gene of Interest into Vector a. Cut the plasmid with same restriction enzymes used on gene of interest

2. Place the Gene of Interest into Vector b. DNA Ligase attaches the gene of interest to the cut plasmid

2. Place the Gene of Interest into Vector c. Form Recombinant DNA. A gene from one organism is put into the genome of a different organism.

2. Place the Gene of Interest into Vector d. Recombinant DNA is placed back into bacteria cell through process called TRANSFORMATION

How is genetic engineering possible? Transformation: When a cell takes up and expresses a new piece of genetic material—DNA— in order to change the organism’s traits DNA Protein Trait RNA

3. Make copies of new cell

Transgenic Organism An organism (animals, plants, and bacteria) that has been genetically altered.

Example #1: Diabetes and Insulin (Medical)

Insulin (protein) helps glucose move from our bloodstream to our cells What is Insulin? Insulin (protein) helps glucose move from our bloodstream to our cells Glucose is from food that was consumed

Type 1 Diabetes: The Pancreas does not produce insulin

Diabetics need to take Insulin shots How does someone with Type 1 Diabetes get insulin? Diabetics need to test their blood sugar Diabetics need to take Insulin shots

History of Insulin Production (finish) Gene that makes insulin in humans was inserted into E.coli (Bacteria) which produced synthetic human insulin

Gel Electrophoresis Christopherson

What is Gel Electrophoresis? Process used to separate fragments of DNA using a charge

1st Step in Electrophoresis Prepare the gel Need agarose, mold, and comb

2nd Step in Electrophoresis Prepare the box Need electrophoresis chamber and buffer

3rd Step in Electrophoresis Load DNA into the wells of the gel using a micropipette DNA Well

4th Step in Electrophoresis Run electricity to separate DNA fragments

5th Step in Electrophoresis Stain the gel to see the DNA fragments Analyze results

+ What is the Result? Larger Fragments Well DNA Fragment ___ Shorter Fragments

EXAMPLE I: WHO IS THE CRIMINAL?