What is the main function of a gene? / To control the production of proteins in an organism’s cells.
Why are proteins important in the cell? / They help determine the size, shape, and other traits of an organism.
What is DNA? / Deoxyribonucleic Acid; the genetic material that carries information about an organism and is carried from parent to offspring.
Where is DNA found? / On Chromosomes
What is DNA made of? / Nitrogen bases; adenine (A), thymine (T), guanine (G), and cytosine (C)
A & T always pair together; G & C always pair together.
Why are the nitrogen bases important? / These bases make up the DNA “ladder” and are always in a specific order. The order of bases along a gene form a genetic code that determines what kind of protein will be produced.
The bases are grouped in 3 – these groups are called codons and code for certain amino acids. Amino acids are important because they are the building blocks of proteins.
Chagraff’s Rule: # A = #T
# G = #C
Franklin was the first to make an image of DNA using X-Ray Diffraction; determined DNA has a spiral shape
Watson & Crick: Used Chagraff & Franklin’s studies to determine that DNA is in the shape of a twisted ladder and built the first model.
What is protein synthesis? / The production of proteins. During synthesis the cell uses information from a gene on a chromosome to produce a specific protein.
Synthesis takes place on ribosomes in the cytoplasm.
Steps of Protein Synthesis
- Messenger RNA Production
- Messenger RNA attaches to a ribosome
- Transfer RNA attaches to Messenger RNA
- Protein Production Complete
What is RNA? / Ribonucleic Acid; sometimes referred to as a genetic messenger.
Has similar nitrogen bases with the exception of thymine. Instead RNA has uracil (U).
What is messenger RNA? / Copies the coded message from DNA and carries the message into the cytoplasm.
What is transfer RNA? / Carries amino acids and adds them to the growing protein.
What is a mutation? / Any change that occurs in a gene or chromosome.
3 Types of Mutation:
1) Deletion: a base is left out
2) Insertion: an extra base is added
3) Substitution: wrong base is used
- occurs most often
What does a mutation mean for an organism? / Mutations cause a cell to produce an incorrect protein. This results in the organism’s traits being different than what they would have been otherwise.
What are the effects of mutations? / Some mutations can be harmful to an organism, others still can be helpful. There are also some mutations that do not help or hurt an organism. Whether a mutation is harmful or not depends on its environment.