Ch.8 - DNA: The Code of Life
Standards covered in this chapter:
7.LS3.1 - Hypothesize that the impact of structural changes to genes (i.e., mutations) located on chromosomes may result in harmful, beneficial, or neutral effects to the structure and function of the organism.
7.LS3.3 - Predict the probability of individual dominant and recessive alleles to be transmitted from each parent to offspring during sexual reproduction and represent the phenotypic and genotypic patterns using ratios.
Important Vocabulary:
DNA Replication - Before a cell divides, the process in which DNA copies itself.
Mutation - any change in the DNA of a gene or a chromosome.
Cancer - A disease in which some body cells grow and divide uncontrollably, damaging the parts of the body around them.
Tumor - a mass of rapidly dividing cells that can damage surrounding tissue.
Chemotherapy - the use of drugs to treat diseases such as cancer.
Sex chromosomes - a pair of chromosomes carrying genes that determine whether a person is male or female.
Sex-linked gene - a gene that is carried on a sex chromosome.
Carrier - a person who has one recessive allele and one dominant allele for a trait.
Messenger RNA - type of RNA that carries copies of instructions for the assembly of amino acids into proteins from DNA to ribosomes into the cytoplasm.
Transfer RNA - carries amino acids to the ribosome and adds them to the growing protein.
Summary
The order of the nitrogen bases along a gene forms a genetic code that specifies what type of protein will be produced. During protein synthesis, the cell uses information from a gene on a chromosome to produce a specific protein. Mutations can cause a cell to produce an incorrect protein during protein synthesis. This may result in abnormal traits. Cancer begins when mutations disrupt the normal cell cycle, causing cells to divide in an uncontrolled way. Human traits may be controlled by single genes with two alleles, by single genes with multiple alleles, or by many genes that act together. Sex chromosomes carry genes that determine whether a person is male or female as well as other traits.
Genetic mutations are caused by any change in the DNA of a gene or a chromosome.
Cancer is a disease caused by body cells growing and dividing uncontrollably.
