- There are approximately 23,000 genes in the human genome.
- Genes are the units of instruction that the cells of the human body use to carry out their functions.
- There are over 200 different types of cells in the human body (for example, muscle cells, liver cells, and nerve cells).
- A genome is the complete collection of hereditary information for an individual organism. In cellular life forms, the hereditary information exists as DNA.
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- A chromosome, by definition, is a threadlike strand of DNA in a cell nucleus that carries genes.
- Human cells have 23 pairs of nuclear chromosomes. A chromosome is made up of a DNA molecule that contains genes.
- There are 24 distinct human chromosomes out of which 22 are autosomal chromosomes and the remaining two are sex-determining chromosomes.
- Every individual has two sets of the 22 chromosomes, X chromosome from the mother and an X or a Y chromosome from the father.
- Chromosomes are in the nucleus.
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- Living organisms are a product of genes that they inherit and enviromental factors that have acted on them.
- A gene is a section of DNA.
- The DNA molecule is made up of base pairs. Genes are sections of these.
- A human gene may be 3,000 base pairs long of a chromosome.
- Each gene is a code specifying a particulat combination of amino acids, that will make a specific protein.
- Different versions of a gene is called an allele.
- If yu have a brown eyes allele from one parent and a blue eye allele from the ther parent. The blue allele will not show.
- It takes 8 hours for 1 of your cells to completely copy it's DNA.
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- Humans have 23 pairs of chromosmes.
- Your gender is controlled by pair 23 called the sex chromosome.
- They are represented by X AND Y.
- XX represents girl.
- XY represents boy.
- The possible genders for parents would be XY or XX.
- Punnett square:
F X X
T X XX XX
E Y YX YX
50% chance of a boy
50% chance of a girl
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- A different version of a gene is called an allele.
- One allele is always dominent
- One allele is always recessive
- If you inherit a dominent allele you will have his characteristic
- If you inherit a recessive allele it will only show affect if both parents have it.
- Dominent alleles with a capital letter
- Recessive alleles with a lower letter.
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