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

Cross two heterozygous purple flowers. What will be the results? X Pp Pp

Pp x Pp P p P PP Pp p Pp pp

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

Multiple Alleles

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 blood type AB marries a woman whose genotype is O A man with blood type AB marries a woman whose genotype is O. What blood types will their children have?

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

Caused by 2 recessive alleles Recessive Disorder 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

How does it happen? Affected Genotype: cc

Red blood cells carry oxygen. Sickle Cell Anemia Caused by an abnormal hemoglobin shape which causes the red blood cells to have a crescent shape. Red blood cells carry oxygen.

How does it happen? Affected Genotype: ss

Dominant Disorder 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.

How does it happen? Affected Genotype: HH or Hh

Sex-Linked Disorder Linked to sex chromosomes Recessive Disorders – caused by recessive alleles

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

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

How does it happen? Affected Genotypes: XbXb XbY

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

How does it happen? Affected Genotypes: XhXh XhY

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?

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

What type of Inheritance? What is genotype of Individual I-1? How many generations? What type of Inheritance? What is genotype of Individual I-1?

Genetic Engineering Christopherson

This means that the sequence of the genes within our DNA is known Human Genome Project 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

The complete set of genetic material of an organism Genome The complete set of genetic material of an organism

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

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

Example of Gene Therapy Cystic Fibrosis: Recessive Disorder

A healthy gene for cystic fibrosis is inserted into a vector “vehicle” and then inhaled by an affected individual.

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

Example of Gene Therapy Cystic Fibrosis: Recessive Disorder

A healthy gene for cystic fibrosis is inserted into a vector “vehicle” and then inhaled by an affected individual.

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Example #1: Diabetes and Insulin (Medical)

Example #2: Genetically Modified Food (GMO’s)

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

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

Example III: WHO IS THE CRIMINAL?