CHAPTER 5: HEREDITY
OBJECTIVE: Students will reconize how biological traits are passed on to successive generations.
SECTION 1 Vocabulary: MENDAL AND HIS PEAS
* HEREDITY- the passing of genetic traits from parents to offspring.
* DOMINANT TRAIT- the trait observed in the first generation when parents that have different traits are bred.
* RECESSIVE TRAIT- the trait that reappears in the second generation after disappearing in the first generation when parents with different.
EXAMPLES OF THE VOCABULARY
* An example of heredity is when flowers cross and self-pollinate. Cross- pollinating is when flower pollen is carried by the wind to another flower. Self-pollinate is when the anther of a flower is pu
SECTION 1 Summary: MENDAL AND HIS PEAS
- Gregor Mendel, a scientist that studies plants, made carefully planned experiments using pea plants that could self-pollinate
- When parents with different traits are bred, dominant traits are always present in the first generation. Recessive traits are not visible in the first generation but reappear in the second generation.
- Mendel found a 3:1 ratio of dominant-to-recessive traits in the second generation.
SECTION 1 Vocabulary: MENDAL AND HIS PEAS
* HEREDITY- the passing of genetic traits from parents to offspring.
* DOMINANT TRAIT- the trait observed in the first generation when parents that have different traits are bred.
* RECESSIVE TRAIT- the trait that reappears in the second generation after disappearing in the first generation when parents with different.
EXAMPLES OF THE VOCABULARY
* An example of heredity is when flowers cross and self-pollinate. Cross- pollinating is when flower pollen is carried by the wind to another flower. Self-pollinate is when the anther of a flower is pu
SECTION 1 Summary: MENDAL AND HIS PEAS
- Gregor Mendel, a scientist that studies plants, made carefully planned experiments using pea plants that could self-pollinate
- When parents with different traits are bred, dominant traits are always present in the first generation. Recessive traits are not visible in the first generation but reappear in the second generation.
- Mendel found a 3:1 ratio of dominant-to-recessive traits in the second generation.
CHROMOSOMES
Each cell in your body has 46 chromosomes, except for your sex chromosomes. Your sex chromosomes only have 23 so that they can mate up with either a sperm or egg to produce a zygote.
SECTION 2 Vocabulary: TRAITS AND INHERITANCE
* ALLELE- one of the alternative forms of a gene that governs a characteristic; such as your hair color.
* PHENOTYPE- an organism's appearence or other detectable characteristic
* GENOTYPE- the entire genetic makeup of an organism; also the combination of genes for one or more specific traits.
* PUNNETT SQUARES- a square is used to organize all the possible combinations of offspring from paticular parents.
* PROBABILITY- the mathmatical chance that something will happen.
* INCOMPLETE DOMINANCE- when two traits do not blend together, but each each allele has its own degree of influence.
SECTION 2 Summary: TRAITS AND INHERITANCE
- Instructions for an inhereited trait are called genes. For each gene, there are two alleles, for one inherited from each parent. Both alleles make up an organism's genotype. Phenotype is an organism's appearence.
- Incomplete dominance occurs when one allele is not completely dominant over the other.
- Some genes influence more than one trait.
- Sometimes one gene influences more than one trait. And sometimes, a trait influences more than one gene.
* ALLELE- one of the alternative forms of a gene that governs a characteristic; such as your hair color.
* PHENOTYPE- an organism's appearence or other detectable characteristic
* GENOTYPE- the entire genetic makeup of an organism; also the combination of genes for one or more specific traits.
* PUNNETT SQUARES- a square is used to organize all the possible combinations of offspring from paticular parents.
* PROBABILITY- the mathmatical chance that something will happen.
* INCOMPLETE DOMINANCE- when two traits do not blend together, but each each allele has its own degree of influence.
SECTION 2 Summary: TRAITS AND INHERITANCE
- Instructions for an inhereited trait are called genes. For each gene, there are two alleles, for one inherited from each parent. Both alleles make up an organism's genotype. Phenotype is an organism's appearence.
- Incomplete dominance occurs when one allele is not completely dominant over the other.
- Some genes influence more than one trait.
- Sometimes one gene influences more than one trait. And sometimes, a trait influences more than one gene.
PUNNET SQUARE
A punnet square is a diagram you use to show all the possible characteristics of a organism. For example, this punnet square shows the possible outcomes for the color of the plant. There is a possibility that the plant can be green or yellow, or a combination of both.
SECTION 3 Vocabulary: MEIOSIS
* MITOSIS- a process of cell division that forms two new nuclei, each of which has the same number of chromosomes.
* CHROMOSOMES- in of the structures in the nucleus that are made of DNA and protein
* MEIOSIS- a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which result in the production of sex cells.
* SEX-LINKED DISORDERS- the genes of certain disorders.
* PEDIGREE- a diagram that shows the occurance of a genetic in several generations of a family.
SECTION 3 Summary: MEIOSIS
- In mitosis, chromosomes are copied once, and then the nucleus divides once. In meiosis, chromosomes are copied once and then the nucleus divides twice.
- The process if meiosis produces sex cells, which have half the number of chromosomes. These halves combine during reproduction.
- In humans, females have two X chromosomes. So each egg contains one X chromosome. Males have both an X and a Y chromosome. So each sperm cell contains either a X or a Y chromosome.
- Sex-linked disorders occur in males, more often than females. Color-blindness and hemophilia are examples of sex-linked disorders.
* MITOSIS- a process of cell division that forms two new nuclei, each of which has the same number of chromosomes.
* CHROMOSOMES- in of the structures in the nucleus that are made of DNA and protein
* MEIOSIS- a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which result in the production of sex cells.
* SEX-LINKED DISORDERS- the genes of certain disorders.
* PEDIGREE- a diagram that shows the occurance of a genetic in several generations of a family.
SECTION 3 Summary: MEIOSIS
- In mitosis, chromosomes are copied once, and then the nucleus divides once. In meiosis, chromosomes are copied once and then the nucleus divides twice.
- The process if meiosis produces sex cells, which have half the number of chromosomes. These halves combine during reproduction.
- In humans, females have two X chromosomes. So each egg contains one X chromosome. Males have both an X and a Y chromosome. So each sperm cell contains either a X or a Y chromosome.
- Sex-linked disorders occur in males, more often than females. Color-blindness and hemophilia are examples of sex-linked disorders.
MEIOSIS
The process of meiosis is the process of the copying of cells with half the usual chromosomes. Each sex cells receives half of the homologous pair. Homologous chromosomes are the chromosomes the same sequence of genes and the same structure. When the sex chromosomes are combined, they have 46 chromosomes.