Download Name Period Chapter 12 Genetics Lesson 1: The Genetic Code

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Period _________________________
Chapter 12 Genetics
Lesson 1: The Genetic Code
What Forms the Genetic Code?
1.
James ____________________ and Francis _______________________published the structure of DNA in 1953.
a. DNA contains the genetic information for cells to make __________________.
b. Proteins ________________ a variety of ________________ from eye color to an organism’s ability to digest
food.
2.
Structure of DNA:
a. Parents pass traits to their children through ____________________________________.
i. Chromosomes are made of __________________ and ___________________________.
ii. Chromosomes are located in the cell’s __________________________.
b. DNA’s structure is described as a “double helix” because it is formed like a twisted ladder.
i. The sides of the ladder are made of _______________ and _______________________molecules.
ii. The rungs of the ladder are made of __________________________ __________________.
1. Adenine
3. Thymine
2. Cytosine
4. Guanine
3.
Chromosome, Genes and DNA
a. Gene: _________________________ ________ __________________ that codes for a protein.
i. A gene can be made of series of ______________________.
ii. Each gene is located at a specific _____________ on a ___________________________.
b. DNA: contains many genes and are unique to an individual organism.
i. DNA is found in all cells of your body except red blood cells.
c. Chromosomes are made of both ________________ and ______________________.
gene
DNA
chromosome
Nitrogen bases
4. Order of the nitrogen bases:
a. The order of the nitrogen bases along a gene forms a ___________ ______________ that specifies what
type of __________________will be produced.
b. Proteins are made of _________________________ _____________________.
c.
A group of _______ DNA bases codes for one _________________ ________________.
How does DNA copy itself?
1. When you need new cells, an existing cell __________________ into ______ ___________ ________________.
2. Before the cell divides it must make a ________________ ________ _______________ so that each new cell has a set.
3. DNA replication: process in which an __________________ copy of a ___________ strand is formed in a ______ ______.
a. The _____ ____________ of the DNA molecule __________________ and ________________.
b. ______________ _____________ in the nucleus _____________ ____ with bases on each half of the DNA molecule.
c. The _______________ _________ ______ _____________________ in each new DNA molecule are _______________ to
the order in the original DNA molecule.
Lesson 2: What is Heredity?
1.
What did Mendel observe?
a. Gregor Mendel is known as the Father of Genetics.
b. He was a priest in the mid-nineteenth century.
c. Mendel observes various traits found in pea plants.
d. Heredity: passing on of physical characteristics, or traits, from parent to offspring.
e. Mendel’s Experiments:
1) His experiments form the foundation of ________________, the study of heredity.
2) In plants, the female reproductive organ, the _________________, produces ___________ cells.
The male reproductive organ, the ____________________, produces________________, or sperm.
When these 2 sex cells unite a new organism begins to grow.
3) Fertilization is the _____________ of ____ __________ ___________ (egg and sperm).
4) Mendel crossed different purebred plants to study their traits.
5) A purebred, is the offspring of many generations that show the _________ __________ _____ _________.
2.
How do alleles affect inheritance?
a. Genes: ________________ _____ ___________________ that control inheritance traits.
b. Alleles are the _____________________ ______________ of a gene. (Ex. Blue, brown, or green eyes)
c. Each pea plant inherits ______ _______________for a trait, one from the egg cell and one from the pollen.
d. Some alleles are dominant (this trait will _____________ ___________ ________ when this allele is present).
*Dominant allele is indicated with a _______________ letter.
e. Some alleles are recessive (this trait is ______________ when the dominant allele is present).
*Recessive allele is indicated with a _____________ ______________ letter.
f. A hybrid is an organism that has ___________ _______________________ alleles for a trait. (A brown eyed
allele and a blue eyed allele).
Lesson 3: Probability and Heredity
How is probability related to inheritance?
1. Probability is the ________________ that describes ______ ____________ it is that an ____________ ________ _________.
2. The laws of probability predict what is ____________ _________ _______________, not what will occur.
3. Each event is ______________________ _____ ____________________. If there is a 1 in 2 chance that when you flip a
coin it will be heads, then each time you flip the coin there is a 1 in 2 chance.
4. Mendel recognized that the laws of probability applied to heredity.
What are Phenotype and Genotype?
1. Phenotype is the _____________________ _________________________, or visible traits of an organism.
2. Genotype is the ___________________ __________________ ______, or alleles, of an organism.
3. Homozygous refers to organisms that ______ _____________________ ___________ for a trait. (two brown eyed
alleles)
4. Heterozygous refers to organism that has ______ __________________ _____________ for a trait. ( one brown
and one blue eyed allele)
Lesson 4: Chromosomes and Inheritance
Chromosomes and inheritance:
1. Walter Sutton studied grasshoppers to discover how sex cells (eggs and sperm) form.
2. He hypothesized that chromosomes are the key to understanding how offspring have traits similar to
those of their parents.
3. He discovered that grasshopper sex cells have ½ of the number of chromosomes found in grasshopper
body cells.
4. He found that when the egg and sperm joined the grasshopper had a complete set of chromosomes
(24) and that the chromosomes worked in pairs.
5. Sutton realized that paired alleles are carried on paired chromosomes.
6. Chromosome Theory of Inheritance: genes pass from parents to their offspring on chromosomes.
7. Genes are joined together on chromosomes.
Meiosis: process by which the ________________of chromosomes is ________________ in ________ as _______
_______________ form.
1.
2.
3.
4.
5.
6.
7.
Chromosomes duplicate themselves. (46 + 46= 92)
Chromosome pairs line up in center of cells.
The pairs move to opposite ends of the cell.
2 cells form. (46 chromosomes in each-****still too many)
In each cell, the chromosomes move to the center again.
The chromatids separate and move to opposite ends of cell.
Each cell divides, creating 4 sex cells. (each now has 23 chromosomes)
Comparing Sexual and Asexual reproduction:
Sexual Reproduction
Asexual Reproduction
1. 2 parents
2. Combination of physical characteristics
3. Offspring have characteristics of
both parents. (variation)
4. Meiosis
1. 1 parent
2. Exact characteristics of parent
3. Offspring is identical to parent. (no
variation)
4. Mitosis