Matched sets of chromosomes provides you with two copies of each gene. Dramactic differences in body and brain cells are due to which genes are “expressed” or activated. Genes make up less than 2% of human DNA. pg 352 8. Define each of the following terms: Conception- when chromosomes of the biological mother and father combine to form a single cell –the fertilized egg or zygote.
Monohybrid inheritance Inheritance in general is the passing of characteristics from parents to offspring, while monohybrid inheritance is the inheritance for a single characteristic/gene. A gene is a length of DNA that occupies a specific position on a chromosome which is called a locus. A particular gene may have more than one form that is slightly different from the others. These different forms of genes are called alleles. Alleles therefore are various molecular forms of a gene for the same trait.
January 11, 2014 Pgs: 250-257 AP Biology Meiosis and Sexual reproduction 1. Differentiate between haploid and diploid cells. Give one example of each cell. The difference between a haploid and a diploid cell is that a diploid is a cell that has two sets of chromosomes. On the other hand, a haploid cell contains only one set of chromosomes.
Meiosis is a type of cell division required for sexual reproduction and produces gametes or spores. During Meiosis I, DNA replication occurs and chromosomes line up on the equator as a homologous pair known as chromatids. At the first stage of Meiosis, Prophase I, DNA of individual chromosomes coils more and more tightly, known as DNA condensation. Sister chromatids then attach to specific sites on the nuclear envelope to bring the homologous pair of chromosomes close together. The sister chromatids line up so they can pair up with its corresponding "sister gene" on the homologous chromosome.
Each parent has a gene pair in each cell for each trait studied. The F1 from a cross of two pure lines contains one allele for the dominant phenotype and one for the recessive phenotype. These two alleles comprise the gene pair. One member of the gene pair segregates into a gamete, thus each gamete only carries one member of the gene pair. Gametes unite at random and irrespective of the other gene pairs involved.
With genetic crossing one will observe the phenotypic, the physical observation, received from the genotype, genetic make-up of organism. Genotypes consist of chromosomes. Chromosomes are found in the cells which organize the structure of DNA and protein. It is a single strand of DNA that contains many genes and other nucleotide sequences. A gene is a region that can be located in the genomic sequence that corresponds to a unit of inheritance; it is instructions that consist of alleles (Wikipedia).
1.What is the Law of Segregation? The Law of Segregation is members of a pair of homologous chromosomes separate during the formation of gametes. 2. What is the Law of Independent Assortment? The Law of Independent Assortment is each member of a pair of homologous chromosomes separated by itself.
What does the Law of Independent Assortment describe? What is the expected phenotypic ratio of a dihybrid cross of two heterozygous parents according to this law? Apply the law to the example given in class of students lining up in pairs and also explain how this contributes to genetic diversity. Independent assortment describes that during gamete formation in an F2 cross, a particular allele for one character can be paired with either allele of another character. An example would be a cross between two plants with two characters, R and Y.
2. Copy the table and match the following terms with their definitions: Gene, traits, chromosome, DNA, Genetics, Asexual reproduction, Meiosis, homozygous, heterozygous, allele, phenotype, genotype Term Definition traits Characteristics passed from parents to offspring chromosomes Thread like structures in the nucleus which carry the genes. allele Alternative forms of a gene Gene A part of a chromosome that carries an instruction homozygous Pure breeding for a characteristic eg: TT for tall DNA Deoxyribonucleic acid Genetics Study of Heredity Phenotype The appearance of an individual Geneotype The alleles an individual has for a particular gene. meiosis Two cell divisions resulting in sex cells that contain half the normal number of chromosomes Asexual Formation of new individuals without the production of reproduction sex cells heterozygoys Hybrid (containing two different alleles) eg: Tt (tall) 3. Answer True or False a) A chromosome is found in the nucleus of a cell.