one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
They are alternative forms, each arising from a different mutation
a molecule that encodes all the information needed to sustain life
How much ( approx ) genes does DNA have
A portion of DNA whose sequence of nucleotides (A< and T) encodes a protein
How is DNA in eukaryotes packaged
They are divided among multiple chromosomes
They are long strands of DNA ( in its condensed form) with associated proteins
contain two sets of chromosomes, with one set inherited from each parent
The human genome consists of how many chromosomes
chromosomes that are the same for both sexes ( somatic cells)
The single pair of chromosomes that determines whether a person is male or female
A female is designated with what sex chromosome
a person with two (2) X chromosomes :XX
A male is designated with what sex chromosome
has (1) X and (1) Y : XY
An analogy to the human genome stored on DNA is that of instructions stored in a book:
.The book (genome) would contain 23 chapters (chromosomes);
.Each chapter contains 48 to 250 million letters (A,C,G,T) without spaces;
.Hence, the book contains over 3.2 billion letters total;
.The book fits into a cell nucleus the size of a pinpoint;
.At least one copy of the book (all 23 chapters) is contained in most cells of our body. The only exception in humans is found in mature red blood cells which become enucleated during development and therefore lack a genome.
are similar but not identical. Each carries the same genes in the same order, but the alleles for each trait may not be the same. In garden peas, for example, the gene for pod colour on the maternal chromosome might be the yellow allele; the gene on the homologous paternal chromosome might be the green allele.
They look alike and have the same sequence of genes in the same position, but may or may not carry the same alleles (translation/ version of the gene)
How many alleles of each gene does each person inherit
2 allele for each gene, since homolog comes from a different parent
An analogy for the 2 alleles for each gene
are comparable to two brownie recipes in a cell may be exactly the the same , slightly different or very different from each other.
with the exception of identical twins , everyone inherits a unique combination of alleles for all the genes in the human genome.
a specialized form of cell division that occurs in diploid cells and give rise to haploid cells
each containing 1 set of of chromosomes ( n=23)
each contain 2 sets of chromosomes in each cell. 2n =46
What pairs of chromosomes are not homologous
The sex chromosomes X and Y
A gene’s LOCUS
Is its physical place on the chromosome
Haploid cells in humans/ sex cells
1. egg cells
2. sperm cells
They are the cells that convey chromosomes from one generation to the next
unites the gametes from 2 parents
Describe the relationships among chromosomes, DNA, genes, and alleles.
Chromosomes contain tightly packed DNA and associated proteins. DNA are the strands of genetic material that contains genes, sequences of nucleotides that code for amino acids. Those genes come in varieties called alleles.
How do meiosis, fertilization, diploid cells, and haploid cells interact in a sexual life cycle?
Meiosis in the adult organism creates the haploid gamete cells that combine during fertilization to form the diploid zygote cell. That cell undergoes mitosis to make the cells that are necessary for growth into the adult form.