VOCABULARY CHAPTER 10

• Gene

• Homologous chromosome

• Gamete

• Haploid

GENES• Segment of DNA on a chromosome that controls the production of proteins

• Each gene plays a role in determining the characteristics or traits of an organism such as: hair color, height, eye color, etc.

HOMOLOGOUS CHROMOSOMES

• Pair of chromosomes that consists of one set of chromosomes from the father and one set from the mother

• Homologous chromosomes will have the same length and the same centromere position and they carry genes that control the same inherited traits

GAMETES•Sex cells that contain half the number of chromosomes

• In humans our egg or sperm cells, which contain 23 chromosomes (unlike the rest of our cells that contain 46 chromosomes)

HAPLOID•A cell with a single set of chromosomes, n

•Gamete cells are haploid cells

VOCABULARY CHAPTER 10

• Fertilization

• Diploid

• Meiosis

• Crossing over

FERTILIZATION• Process of one haploid gamete combining

with another haploid gamete

• Results in a cell containing a total of 2n chromosomes

• Example humans: an egg cell containing 23 chromosomes from female parent and a sperm cell containing 23 chromosomes combine to form a cell with 46 chromosomes

DIPLOID•A cell that contains 2n number of chromosomes

• In humans n=23, so human diploid cells have 2x23 or 46 chromosomes, or say it as 23 pairs of homologous chromosomes

MEIOSIS• Type of cell division that reduces the number of chromosomes, forming gamete cells

• Contains two consecutive cell divisions called meiosis 1 and meiosis 2

• Resulting with four haploid cells

CROSSING OVER• This process of chromosomal segments being exchanged occurs during synapsis when the homologous chromosomes are paired and held tightly together

• Results are new combinations of genes

VOCABULARY CHAPTER 10

•Genetics•Allele•Dominant•Recessive

GENETICS

•Science of heredity

•Mendel – regarded as the father of genetics

ALLELE• An alternative form of a single gene passed from generation to generation

• Example: two forms of a seed trait in pea plants, yellow seed and green seed, each controlled by an allele which are different forms of a single gene

DOMINANT•An allele that can mask another allele in the F1 generation, which means the trait represented by that allele will show over the other trait

•Represented with a capital letter

RECESSIVE

•The form of an individual trait that is masked in the F1 generation

•Represented with a lowercase letter

VOCABULARY CHAPTER 10

• Homozygous

• Heterozygous

• Genotype

• Phenotype

HOMOZYGOUS

•An organism with two of the same alleles for a particular trait

•Example: Homozygous, yellow-seed plants are YY and green-seed plants are yy

HETEROZYGOUS

• An organism with two different alleles for a particular trait

• Example: For seed color trait a heterozygous organism would have Yy alleles, where the dominant trait will be observed

GENOTYPE

• An organisms allele pairs

• Represented by letters

• Example: In the case of plants with yellow seeds, their genotype could be YY or Yy

PHENOTYPE• The observable characteristic or outward expression of an allele pair

• The trait that is expressed or observed

• Example: In pea plants with the genotype of Yy the phenotype will be yellow seeds