1. Genetics: The Science of Heredity
The DNA Connection
Genetics: The Science of Heredity

2. The Genetic Code Genes control the function of proteins.
A gene is a section of a DNA molecule that contains info to code for one specific protein.
Proteins help determine the size, shape, color, etc. of organisms.
Chromosomes are composed of DNA.
DNA is made of phosphate groups, deoxyribose (sugar), and nitrogen bases (adenine, thymine, cytosine, and guanine).

3. The Genetic Code Genes Made up of a series of bases in a row.
The bases are arranged in a specific order.
Each gene is located at a specific place on a chromosome for every organism in a specific species.

4. The Genetic Code
Genes contain the code that determines the structure of a protein.
The order of nitrogen bases along a gene forms a genetic code that specifies what type of protein will be produced.
Proteins are long chain molecules made of amino acids.

5. Nitrogen Bases (Genes)
The Genetic Code
Nitrogen Bases (Genes)
Amino Acids
Proteins
A group of 3 DNA bases codes for one specific amino acid (CODON)
Amino Acids are the building blocks of proteins (they make proteins).
The order of the codons determines the order in which amino acids form proteins.
Code for…
Which build…

6. The Genetic Code

7. Protein Synthesis
During PROTEIN SYNTHESIS, the cell uses information from a gene on a chromosome to produce specific proteins.
Protein synthesis happens in the ribosomes in the cytoplasm of a cell.

8. DNA vs. RNA RNA DNA Double stranded Single stranded
The sugar is DEOXYRIBOSE
Nitrogen Bases are: adenine, thymine, cytosine, and guanine
Single stranded
The sugar is RIBOSE
Nitrogen Bases are: adenine, uracil (instead of thymine), cytosine, and guanine.

9. The Role of RNA
Messenger RNA copies the coded message from the DNA in the nucleus, and carries the message to the ribosome.
Transfer RNA carries amino acids to the ribosomes and adds them to growing proteins.

10. Steps of Protein Synthesis
Messenger RNA (mRNA) production (transcription)
Takes place in the nucleus
DNA is “unzipped” between base pairs, and RNA is matched up.
Messenger RNA leaves nucleus and attaches to the Ribosomes.
Production of protein takes place here.
Transfer RNA attaches to Messenger RNA.
tRNA carries specific amino acids to the ribosome.
By matching the codons and adding amino acids, the tRNA and mRNA build proteins.
The protein grows until the ribosome reaches a stop codon on the RNA.

11. Steps of Protein Synthesis
DNA
Messenger RNA
Transfer RNA
Amino Acids
Proteins

12. The Role of RNA DISSCUSSION STOP POINT
Does this strand come from DNA or RNA? Explain your answer.

13. Mutations A mutation is any change in a gene or chromosome.
Mutations cause cells to produce incorrect proteins during protein synthesis.

14. Types of Mutations
Mutations that can occur during replication include:
Substitution: single base may be changed to another base
Deletion: one or more may be removed from a section of DNA
Some mutations occur when chromosomes don’t separate correctly during meiosis.
Too many chromosomes or too few can be in a cell.

15. Effects of Mutations
Can be harmful if it reduces the organism’s chance of survival and reproduction.
Can be helpful if it improves an organism’s chances for survival and reproduction.