Genetics u Genetics is the branch of science

Genetics

u Genetics is the branch of science heredity that studies _____. Heredity u ____ is the passing of traits from parents to offspring.

Gregor Mendel monastery his research in the _____ Austria u Born in 1822 in _____ u Wanted to figure out why some traits _______ showed up more often then others u Studied garden _____ pea plants u Did

Why Pea Plants? Self u ____ Pollinating _____ -has both male and female reproductive structures on the same plant true____ breeding – Able to grow ____ plants. Plants self pollinated therefore were exactly like the parent. Cross _____-pollen Pollination u _____ from one plant fertilizes the ovule of a different plant wind or _____ insects – Carried by _______

feature Characteristic - A _____ that forms in a population. has different _______ u Mendel studied only one pea characteristic at a time. Traits u _______ - are different forms of a characteristic – _____ Dominant or ______ recessive

Pea Plant Traits Mendel Studied

Mendel’s First Experiments • Mendel crossed pea plants to study seven different characteristics. • Mendel got similar results for each cross. One trait was always present in the first generation, and the other trait seemed to disappear. • Mendel called the trait that appeared the dominant trait. The trait that seemed to fade into the background was called the recessive trait.

Dominant Trait first in the trait that is always ______ organism. u. A u Dominant alleles are symbolized with capital _____ letters

Recessive Trait masked or hidden in the _____ presence of a dominant trait. u Is u Recessive alleles are symbolized with lowercase _____ letters Ratio u _______ - relationship between two different numbers that is often expressed as a fraction.

Traits and Inheritance u ____-Instructions Gene traits for inherited – One from each _____ parent u _____-different Alleles Phenotype u _____-an forms of a gene organism’s appearance Genotype u _____-an organism’s genetic makeup

Homozygous u ________ an organism that two dominant or two _______ recessive has _____ Purebred alleles. ______ example: if T = tall and t = short then TT or tt Heterozygous u ________ an organism has dominant AND a both a _____ recessive hybrid ______ allele. _____ example: if T = tall and t = short then Tt

Heredity In Plants Reading 1. The passing of characteristics from parents to offspring is known as heredity ______ 2. The scientific study of heredity is called _____ genetics 3. The offspring of two purebred plants with contrasting traits is called a hybrid _______ dominant trait will occur more often 4. A _____ recessive then a ______ trait.

More About Gregor Mendel Reading 1. How long was the experiment expected to last? The experiment was expected to last seven years. 2. Why use pea plants? Because they were able to self-pollinate and were easy to grow.

3. Why was the F 1 generation referred to as being hybrid tall? There was one dominant and one recessive allele. The recessive allele is hidden.

Chapter 5 Section 2

1. 2. 3. In _____ asexual reproduction, only one parent cell is needed for reproduction. sexual In _____ reproduction, two parent cells join together to form a new individual. 46 Human body cells have ___ chromosomes.

4. 5. 6. sex cells Human _____ have only 23 ___ chromosomes-half the usually number. Male sex cells are called sperm _____. Female sex cells are called ____. egg Meiosis _____produces new sex cells with half the usual number of chromosomes Genes are located on _____.

7. 8. 9. 10. Sex chromosomes ________ carry genes that determine whether the offspring is male or female. 2 X Females have _____ chromosomes. 1 X Males 1 Y have _____ chromosome and ____ chromosome. THINK! Explain the difference between sex cells and sex chromosomes.

10. THINK! Explain the difference between sex cells and sex chromosomes. u Each sex cell (egg or sperm) contains half of all the chromosomes, including one sex chromosome. The sex chromosome genes are what determine whether an offspring will be male or female.

Punnett Squares

DNA are made of ______ u Genes must be able to supply instructions _____ for cell processes and building cell structures for ____ Watson and ______ u ____ Crick build models of DNA. They conclude that DNA resembles a twisted ladder shape known as a double ______ helix _____ u The structure of DNA can be compared to a _______ u Chromosomes

Incomplete Dominance _____ is when a trait appears to blend together but each allele has his own degree of influence. u ______

u Many things in your environment also influence how you grow and develop – Example: amount of food

Chapter 6 Section 2

Proteins u ______ messenger act as a chemical How tall you are Eye color Mutations u _____ occur when there is a change in the order of bases in a organism’s DNA u The three possible consequences to changes in DNA include: an improvement – __________________ no change at all a harmful change – _________

u. A ____ mutagen is anything that can cause a mutation in DNA Sickle Cell Anemia u _________ is a disease that affects red blood cells counseling provides _____ information and counseling to couples who wish to have children but are worried that they might pass children a disease on to their ____ u Genetic